JP7669705B2 - Transparent laminate film, transparent laminate film with protective film, and face shield - Google Patents

Description

This disclosure relates to a transparent laminate film, a transparent laminate film with a protective film, and a face shield.

Face shields that prevent droplets of saliva and other fluids caused by sneezing or coughing from adhering to the face of the person they are facing have been known (see, for example, Patent Document 1). Patent Document 1 discloses a face shield that is made up of a shield part that is placed in front of the wearer's face and a frame that holds the shield part.

Registered Utility Model No. 3227450

However, such face shields may also be worn by employees at event venues. In such cases, the face shield may be required to have a stylish design to liven up the event. Also, event participants may paint their faces to enhance the sense of unity at the event venue. In such cases, ink or the like is often applied directly to the faces of the participants, which takes time to form the design on the face, and may require even more effort to remove the paint after the event has ended. For this reason, there is a demand for face shields that can improve their design.

Face shields are also used in medical settings. For example, in medical settings where strict management of epidemic prevention equipment is required, it is desirable to clearly display information on the face shield indicating the wearer's affiliation, the date and time when the epidemic prevention equipment was first used, etc.

This disclosure has been made in consideration of these points, and aims to provide a transparent laminate film, a transparent laminate film with a protective film, and a face shield that can improve design or clearly display text or symbol information.

The transparent laminate film according to one embodiment is a transparent laminate film having a front surface and a back surface, and is provided with at least a core layer and a printed layer covering a portion of the front surface side or a portion of the back surface side of the core layer, and in the area where the printed layer is not provided, the luminous reflectance Y value is 0.0% or more and 2.0% or less.

In one embodiment of the transparent laminate film, in the area where the printed layer is not provided, the reflectance of light having a wavelength of 550 nm may be 2% or less, and the total light transmittance may be 90% or more.

In one embodiment of the transparent laminate film, in the area where the printed layer is not provided, the transmittance in the ultraviolet range of wavelengths of 380 nm or less may be 1% or less.

In one embodiment of the transparent laminate film, the core layer may contain polyethylene terephthalate.

In one embodiment, the transparent laminate film further includes a front-side antireflection layer provided on one side of the core layer and constituting the front side, and a back-side antireflection layer provided on the other side of the core layer and constituting the back side, and the printed layer may be provided between the core layer and the front-side antireflection layer.

In one embodiment, the transparent laminate film further includes a front-side antireflection layer provided on one side of the core layer and constituting the front side, and a back-side antireflection layer provided on the other side of the core layer and constituting the back side, and the printed layer may be provided between the core layer and the back-side antireflection layer.

In one embodiment of the transparent laminate film, the transparent laminate film may further include a first transparent adhesive layer that bonds the front-side antireflection layer and the core layer, and a second transparent adhesive layer that bonds the core layer and the rear-side antireflection layer.

In one embodiment of the transparent laminate film, the first transparent adhesive layer and the second transparent adhesive layer may each contain an acrylic adhesive.

The transparent laminate film according to one embodiment includes a front-side antireflection layer constituting the front surface, a back-side antireflection layer constituting the back surface, and a printed layer provided between the front-side antireflection layer and the back-side antireflection layer and covering a portion of the front-side antireflection layer, and has a luminous reflectance Y value of 0.0% or more and 2.0% or less in the region where the printed layer is not provided.

In one embodiment of the transparent laminate film, in the area where the printed layer is not provided, the reflectance of light having a wavelength of 550 nm may be 2% or less, and the total light transmittance may be 90% or more.

In one embodiment of the transparent laminate film, in the area where the printed layer is not provided, the transmittance in the ultraviolet range of wavelengths of 380 nm or less may be 1% or less.

In one embodiment of the transparent laminate film, the front-side antireflection layer may have a front-side antireflection functional layer and a front-side transparent substrate layer arranged in that order from the front side to the back side, and the back-side antireflection layer may have a back-side antireflection functional layer and a back-side transparent substrate layer arranged in that order from the back side to the front side.

In one embodiment of the transparent laminate film, the front-side antireflection functional layer may be a coating layer coated on the front-side transparent substrate layer, and the back-side antireflection functional layer may be a coating layer coated on the back-side transparent substrate layer.

In one embodiment of the transparent laminate film, the front-side antireflection functional layer and the back-side antireflection functional layer may each be made of a cured product of an ionizing radiation curable resin composition.

In one embodiment of the transparent laminate film, the ionizing radiation curable resin composition may contain a (meth)acrylate compound.

In one embodiment of the transparent laminate film, the front-side antireflection layer includes a front-side refraction layer and a front-side hard coat layer arranged in this order from the front side to the back side, and the back-side antireflection layer may include a back-side refraction layer and a back-side hard coat layer arranged in this order from the back side to the front side.

In one embodiment of the transparent laminate film, the front hard coat layer may be a coating layer coated on the front transparent substrate layer, the front refractive layer may be a coating layer coated on the front hard coat layer, the rear hard coat layer may be a coating layer coated on the rear transparent substrate layer, and the rear refractive layer may be a coating layer coated on the rear hard coat layer.

In one embodiment of the transparent laminate film, the surface refractive layer may include a surface low refractive index layer and a surface high refractive index layer arranged in that order from the surface to the back surface, and the back surface refractive layer may include a back surface low refractive index layer and a back surface high refractive index layer arranged in that order from the back surface to the surface.

In one embodiment of the transparent laminate film, the surface high refractive index layer may include a first surface high refractive index layer and a second surface high refractive index layer arranged in order from the surface to the back surface, and the back surface high refractive index layer may include a first back surface high refractive index layer and a second back surface high refractive index layer arranged in order from the back surface to the surface.

In one embodiment of the transparent laminate film, the refractive index of the first surface high refractive index layer may be higher than the refractive index of the second surface high refractive index layer, and the refractive index of the first back surface high refractive index layer may be higher than the refractive index of the second back surface high refractive index layer.

In one embodiment of the transparent laminate film, the front transparent substrate layer and the back transparent substrate layer may contain triacetyl cellulose or polyethylene terephthalate.

In one embodiment of the transparent laminate film, one of the front transparent substrate layer and the back transparent substrate layer may contain triacetyl cellulose, and the other may contain polyester.

In one embodiment of the transparent laminate film, the front transparent substrate layer and the back transparent substrate layer may each contain polyester.

In one embodiment, the transparent laminate film may have a thickness of 40 μm or more and 500 μm or less.

The transparent laminate film according to one embodiment may have a restoring function.

The transparent laminate film according to one embodiment may be used in a face shield to protect the wearer's face.

The transparent laminate film with protective film according to one embodiment is a transparent laminate film with protective film, comprising a transparent laminate film according to one embodiment, a surface protective film that protects the surface of the transparent laminate film, and a back protective film that protects the back surface of the transparent laminate film.

A face shield according to one embodiment is a face shield that protects the face of a wearer, and includes a holding member that is worn by the wearer, and a transparent laminate film according to one embodiment that is attached to the holding member and covers at least a portion of the wearer's face.

In one embodiment of the face shield, the printed layer may be positioned so as to overlap the cheek of the wearer when viewed from the front.

In one embodiment of the face shield, when the wearer is wearing the face shield, the distance between the wearer's nose and the retaining member may be 100 mm or less.

In one embodiment of the face shield, the retaining member may have a pair of temple portions that come into contact with the wearer's ears, a front portion that connects the pair of temple portions together, and a pair of pad portions that extend downward from the front portion and come into contact with the wearer's nose.

In one embodiment of the face shield, the retaining member may have a band that circumferentially covers the wearer's head.

In one embodiment of the face shield, the retaining member has a chin pad that contacts the wearer's chin and a pair of hooks that are connected to the chin pad and hooked onto the wearer's ears, and the transparent laminate film may cover at least the wearer's mouth.

According to the present disclosure, it is possible to improve the design of transparent laminate films and face shields, or to clearly display text or symbol information on transparent laminate films and face shields.

FIG. 1 is a perspective view showing a face shield according to the present embodiment. FIG. 2 is a top view showing the face shield according to the present embodiment. FIG. 3 is a front view showing the shield portion of the face shield according to the present embodiment. FIG. 4A is a cross-sectional view showing an example of a layer structure of a transparent laminate film with a protective film according to the present embodiment. FIG. 4B is a cross-sectional view showing an example of the layer structure of the protective film-attached transparent laminate film according to the present embodiment. FIG. 4C is a cross-sectional view showing an example of a layer structure of the protective film-attached transparent laminate film according to the present embodiment. FIG. 4D is a cross-sectional view showing an example of the layer structure of the protective film-attached transparent laminate film according to the present embodiment. FIG. 4E is a cross-sectional view showing an example of a layer structure of the protective film-attached transparent laminate film according to the present embodiment. FIG. 4F is a cross-sectional view showing an example of the layer structure of the protective film-attached transparent laminate film according to the present embodiment. FIG. 4G is a cross-sectional view showing an example of the layer structure of the protective film-attached transparent laminate film according to the present embodiment. FIG. 4H is a cross-sectional view showing an example of the layer structure of the protective film-attached transparent laminate film according to the present embodiment. FIG. 4I is a cross-sectional view showing an example of the layer structure of the protective film-attached transparent laminate film according to the present embodiment. FIG. 4J is a cross-sectional view showing an example of a layer structure of the protective film-attached transparent laminate film according to the present embodiment. FIG. 5 is a perspective view showing a modification of the face shield according to the present embodiment. FIG. 6 is a perspective view showing a modification of the face shield according to the present embodiment. FIG. 7 is a perspective view showing another example of use of the transparent laminate film according to the present embodiment. FIG. 8 is a front view showing the transparent laminate film of FIG.

An embodiment will be described below with reference to the drawings. Figures 1 to 4J are diagrams showing an embodiment. Each of the figures shown below is a schematic diagram. Therefore, the size and shape of each part are appropriately exaggerated to facilitate understanding. In addition, appropriate modifications can be made without departing from the technical concept. In each of the figures shown below, the same parts are given the same reference numerals, and some detailed explanations may be omitted. In addition, the numerical values such as dimensions of each member and the material names described in this specification are examples of an embodiment, and are not limited to these, and can be selected and used as appropriate. In this specification, terms that specify shapes or geometric conditions, such as parallel, orthogonal, and perpendicular, are intended to include substantially the same state in addition to their strict meanings.

1 to 3, a face shield 10 including a transparent laminate film 30 according to the present embodiment will be described. The face shield 10 is for protecting the face F of a wearer H.

1 and 2, the face shield 10 comprises a retaining member 20 worn by a wearer H, and a shield portion 30A (transparent laminate film 30) attached to the retaining member 20 and covering the face F of the wearer H. Of these, the retaining member 20 has a pair of temple portions 21 that come into contact with the ears E of the wearer H, a front portion 22 that connects the pair of temple portions 21 to each other, and a pair of pad portions 23 that extend downward from the front portion 22 and come into contact with the nose N of the wearer H. In this embodiment, the retaining member 20 is of the so-called eyeglass frame type.

As shown in FIG. 2, this type of holding member 20 holds the shield portion 30A so that when the wearer H wears the face shield 10, a desired gap is formed between the wearer H's nose N, mouth, etc. and the shield portion 30A.

When the wearer H wears the face shield 10, the distance D1 (see FIG. 2) between the nose N of the wearer H and the shield part 30A is preferably 100 mm or less, more preferably 3 mm or more and 100 mm or less, and even more preferably 5 mm or more and 100 mm or less. By making the distance D1 3 mm or more, it is possible to prevent the transparent laminate film 30 constituting the shield part 30A from coming into contact with the face F of the wearer H when the wearer H moves his/her head. Therefore, even when the wearer H wears the face shield 10, the wearer H can concentrate on his/her work without feeling stress. In addition, by making the distance D1 100 mm or less, it is possible to prevent the transparent laminate film 30 constituting the shield part 30A from coming into contact with surrounding structures or other people when the wearer H moves his/her head. In addition, by making the distance D1 100 mm or less, it is possible to prevent the weight of the face shield 10 from becoming too large. Therefore, even when the wearer H is wearing the face shield 10, the wearer H can concentrate on his/her work without feeling stressed. Furthermore, by setting the distance D1 to 100 mm or less, droplets of saliva, etc., caused by the wearer H sneezing or coughing can be effectively prevented from landing on the face of another person, and droplets of saliva, etc., caused by another person sneezing or coughing can be effectively prevented from landing on the wearer H's face.

There are no restrictions on the material of the retaining member 20, but from the standpoint of flexibility, light weight, ease of procurement, etc., it is desirable for the retaining member 20 to be made of resin. The resin material used for the retaining member 20 can be selected from resin materials that are generally used.

The shield part 30A serves to prevent droplets of saliva, etc., caused by sneezing or coughing by the wearer H from adhering to the face of another person, and droplets of saliva, etc., caused by sneezing or coughing by another person from adhering to the face F of the wearer H. This shield part 30A is composed of a transparent laminated film 30. In this embodiment, the shield part 30A covers the entire face F of the wearer H. The shape of the shield part 30A is arbitrary, and the shield part 30A may have a rectangular shape, a rectangular shape with rounded corners, an elliptical shape, etc. From the viewpoint of preventing droplets from scattering, it is preferable that the size of the shield part 30A is a certain size or more, and it is preferable that the size is a square of 10 cm square or more. In addition, from the viewpoint of not interfering with the movement of the wearer H, it is preferable that the size is a square of 40 cm square or less.

In this embodiment, the shield part 30A (transparent laminate film 30) has a printed layer 33. As shown in FIG. 3, the printed layer 33 is provided at a position overlapping the cheek C of the wearer H in front view. This allows the observer to have the impression that the characters or the like displayed by the printed layer 33 are printed directly on the face F. In this case, when the shield part 30A is removed from the holding member 20, it is preferable that the printed layer 33 is provided in an area with a length L from the central axis CL of the shield part 30A of 100 mm or less. This allows the printed layer 33 to overlap the cheek C of the wearer H when the wearer H wears the face shield 10. The printed layer 33 may display information such as characters, figures, marks, and other patterns and letters. In the illustrated example, the printed layer 33 displays a star-shaped, moon-shaped, or flower-shaped pattern. It is also preferable that the printed layer 33 is provided at a position that does not overlap the eyes of the wearer H in front view.

This shield part 30A may be attached to the holding member 20 via an attachment member (not shown). Alternatively, although not shown, for example, an engaging part such as a protrusion may be provided on the holding member 20, and an engaged part such as a through hole may be provided on the shield part 30A. Then, the engaged part may engage with the engaging part, thereby attaching the shield part 30A to the holding member 20.

Transparent laminate film with protective film Next, a transparent laminate film 60 with a protective film according to the present embodiment will be described. Figures 4A to 4J show an example of a layer structure of the transparent laminate film 60 with a protective film. As shown in Figures 4A to 4J, the transparent laminate film 60 with a protective film includes the transparent laminate film 30 according to the present embodiment, a surface protective film 61 that protects the surface 301 of the transparent laminate film 30, and a back surface protective film 62 that protects the back surface 302 of the transparent laminate film 30.

Among these, the surface protective film 61 and the back protective film 62 serve to prevent the surface 301 and the back surface 302 of the transparent laminate film 30 from being scratched, and to prevent the surface 301 and the back surface 302 from being contaminated by foreign matter. The surface protective film 61 and the back protective film 62 are each detachably attached to the transparent laminate film 30. The surface protective film 61 and the back protective film 62 each include a bonding layer (not shown), and may be attached to the transparent laminate film 30 by this bonding layer. The adhesive strength of the bonding layer may be, for example, about 0.05 N/25 mm or more and 5 N/25 mm or less. When using the face shield 10 described above, the surface protective film 61 and the back protective film 62 are each peeled off from the transparent laminate film 30. The material of the surface protective film 61 and the back protective film 62 may be, for example, a film made of a polyester resin or a polyolefin such as polyethylene or polypropylene.

Transparent Laminate Film Next, the transparent laminate film 30 according to the present embodiment will be described. As described above, the transparent laminate film 30 may be used in the face shield 10 that protects the face F of the wearer H. As shown in FIG. 4A to FIG. 4H, the transparent laminate film 30 has a front surface 301 and a back surface 302, and at least includes a core layer 32 and a printed layer 33 that covers a part of the surface 301 side of the core layer 32 or a part of the surface 302 side of the core layer 32. The transparent laminate film 30 also includes a front surface antireflection layer 40 that is provided on one side of the core layer 32 and constitutes the front surface 301, and a back surface antireflection layer 50 that is provided on the other side of the core layer 32 and constitutes the back surface 302. Furthermore, the transparent laminate film 30 may further include a first transparent adhesive layer 31a that bonds the front surface antireflection layer 40 and the core layer 32, and a second transparent adhesive layer 31b that bonds the core layer 32 and the back surface antireflection layer 50.

Specifically, as shown in Figures 4A, 4C, and 4E, the transparent laminate film 30 includes, in this order from the front surface 301 to the back surface 302, a front surface antireflection layer 40, a first transparent adhesive layer 31a, a printing layer 33, a core layer 32, a second transparent adhesive layer 31b, and a back surface antireflection layer 50. In this case, in the transparent laminate film 30, the front surface antireflection layer 40 is exposed outward from the front surface 301 side. Also, in the transparent laminate film 30, the back surface antireflection layer 50 is exposed outward from the back surface 302 side.

As shown in Figures 4B, 4D, and 4F, the transparent laminate film 30 includes, in this order from the front surface 301 to the back surface 302, a front surface antireflection layer 40, a first transparent adhesive layer 31a, a core layer 32, a printing layer 33, a second transparent adhesive layer 31b, and a back surface antireflection layer 50. Even in this case, in the transparent laminate film 30, the front surface antireflection layer 40 is exposed outward from the front surface 301 side. In addition, in the transparent laminate film 30, the back surface antireflection layer 50 is exposed outward from the back surface 302 side.

As shown in FIG. 4G, the transparent laminate film 30 includes, in this order from the front surface 301 to the back surface 302, a front surface antireflection layer 40, a printing layer 33, a first transparent adhesive layer 31a, a core layer 32, a second transparent adhesive layer 31b, and a back surface antireflection layer 50. Even in this case, in the transparent laminate film 30, the front surface antireflection layer 40 is exposed outward from the front surface 301 side. In addition, in the transparent laminate film 30, the back surface antireflection layer 50 is exposed outward from the back surface 302 side.

As shown in FIG. 4H, the transparent laminate film 30 includes, in this order from the front surface 301 to the back surface 302, a front surface antireflection layer 40, a first transparent adhesive layer 31a, a core layer 32, a second transparent adhesive layer 31b, a printing layer 33, and a back surface antireflection layer 50. Even in this case, in the transparent laminate film 30, the front surface antireflection layer 40 is exposed outward from the front surface 301 side. In addition, in the transparent laminate film 30, the back surface antireflection layer 50 is exposed outward from the back surface 302 side.

As shown in Figures 4A to 4H, the front-surface antireflection layer 40 has a front-surface antireflection functional layer 41 and a front-surface transparent substrate layer 42 arranged in order from the front surface 301 to the back surface 302. The front-surface antireflection functional layer 41 also includes a front-surface refraction layer 43 and a front-surface hard coat layer 44 arranged in order from the front surface 301 to the back surface 302. Here, as shown in Figures 4C to 4F, the front-surface refraction layer 43 may include a front-surface low-refractive index layer 45 and a front-surface high-refractive index layer 46 arranged in order from the front surface 301 to the back surface 302. As shown in Figures 4E and 4F, the front-surface high-refractive index layer 46 may include a first front-surface high-refractive index layer 47 and a second front-surface high-refractive index layer 48 arranged in order from the front surface 301 to the back surface 302. In the example shown in Figures 4G and 4H, the front-surface antireflection layer 40 has a front-surface antireflection functional layer 41 and a front-surface transparent substrate layer 42, and the front-surface antireflection functional layer 41 includes a front-surface refraction layer 43 and a front-surface hard coat layer 44. In this case, although not shown, in the front-surface antireflection layer 40, as shown in Figures 4C to 4F, the front-surface refraction layer 43 may include a front-surface low-refractive-index layer 45 or the like.

4A to 4H, the back surface antireflection layer 50 has a back surface antireflection functional layer 51 and a back surface transparent substrate layer 52 arranged in order from the back surface 302 to the front surface 301. The back surface antireflection functional layer 51 also includes a back surface refraction layer 53 and a back surface hard coat layer 54 arranged in order from the back surface 302 to the front surface 301. Here, as shown in FIGS. 4C to 4F, the back surface refraction layer 53 may include a back surface low refractive index layer 55 and a back surface high refractive index layer 56 arranged in order from the back surface 302 to the front surface 301. As shown in FIGS. 4E and 4F, the back surface high refractive index layer 56 may include a first back surface high refractive index layer 57 and a second back surface high refractive index layer 58 arranged in order from the back surface 302 to the front surface 301. In the example shown in Figures 4G and 4H, the back surface antireflection layer 50 has a back surface antireflection functional layer 51 and a back surface transparent substrate layer 52, and the back surface antireflection functional layer 51 includes a back surface refraction layer 53 and a back surface hard coat layer 54. In this case, although not shown, in the back surface antireflection layer 50, as shown in Figures 4C to 4F, the back surface refraction layer 53 may include a back surface low refractive index layer 55 or the like.

As shown in Figures 4I and 4J, the transparent laminate film 30 may not include the core layer 32. Specifically, as shown in Figure 4I, the transparent laminate film 30 may include a front surface antireflection layer 40, a printing layer 33, a transparent adhesive layer 31, and a back surface antireflection layer 50 in this order from the front surface 301 to the back surface 302. Even in this case, in the transparent laminate film 30, the front surface antireflection layer 40 is exposed outward from the front surface 301 side. In addition, in the transparent laminate film 30, the back surface antireflection layer 50 is exposed outward from the back surface 302 side.

Also, as shown in FIG. 4J, the transparent laminate film 30 may include a front-side antireflection layer 40, a transparent adhesive layer 31, a printing layer 33, and a back-side antireflection layer 50, in this order from the front side 301 to the back side 302. Even in this case, in the transparent laminate film 30, the front-side antireflection layer 40 is exposed outward from the front side 301 side. In addition, in the transparent laminate film 30, the back-side antireflection layer 50 is exposed outward from the back side 302 side.

In the example shown in FIG. 4I and FIG. 4J, the front-side antireflection layer 40 has a front-side antireflection functional layer 41 and a front-side transparent substrate layer 42, and the front-side antireflection functional layer 41 includes a front-side refraction layer 43 and a front-side hard coat layer 44. The back-side antireflection layer 50 has a back-side antireflection functional layer 51 and a back-side transparent substrate layer 52, and the back-side antireflection functional layer 51 includes a back-side refraction layer 53 and a back-side hard coat layer 54. In this case, although not shown, in the front-side antireflection layer 40, as shown in FIG. 4C to FIG. 4F, the front-side refraction layer 43 may include a front-side low refractive index layer 45, etc., and in the back-side antireflection layer 50, the back-side refraction layer 53 may include a back-side low refractive index layer 55, etc.

As described above, the front-side antireflection layer 40 may have a basic configuration having a front-side high refractive index layer 46 and a front-side low refractive index layer 45 on the front-side transparent substrate layer 42. Also, as described above, the back-side antireflection layer 50 may have a basic configuration having a back-side high refractive index layer 56 and a back-side low refractive index layer 55 on the back-side transparent substrate layer 52. The front-side high refractive index layer 46 (back-side high refractive index layer 56) and the front-side low refractive index layer 45 (back-side low refractive index layer 55) play a role in providing an antireflection function by optical interference function.

The front-surface anti-reflection layer 40 (rear-surface anti-reflection layer 50) may be provided with an anti-reflection function by optical interference of three or more layers by further providing a medium refractive index layer, but it is not preferable from the viewpoint of cost-effectiveness to have too many layers. Therefore, it is preferable that the front-surface anti-reflection layer 40 (rear-surface anti-reflection layer 50) of this embodiment is provided with an anti-reflection function by optical interference of two layers, the front-surface high refractive index layer 46 (rear-surface high refractive index layer 56) and the front-surface low refractive index layer 45 (rear-surface low refractive index layer 55). In addition, the front-surface anti-reflection layer 40 (rear-surface anti-reflection layer 50) may be provided with an anti-reflection function by optical interference of three layers, the medium refractive index layer, the high refractive index layer, and the low refractive index layer, by making the front-surface hard coat layer 44 (rear hard coat layer 54) a medium refractive index layer.

Each layer of the transparent laminate film 30 is described below.

<Front-side antireflection layer and rear-side antireflection layer>
The surface antireflection layer 40 is a layer for suppressing reflection of light incident from the surface 301 side of the transparent laminate film 30. By providing the transparent laminate film 30 with the surface antireflection layer 40, it is possible to suppress reflection of light on the surface 301 of the transparent laminate film 30. This makes it possible to improve the visibility of the face F of the wearer H when, for example, viewing the wearer H wearing the face shield 10. This makes it possible to improve the visibility of the mouth of the wearer H, and facilitate smooth communication between the wearer H and others.

On the other hand, the back surface antireflection layer 50 is a layer for suppressing reflection of light incident mainly from the back surface 302 side of the transparent laminate film 30. By providing the transparent laminate film 30 with the back surface antireflection layer 50, it is possible to suppress reflection of light on the back surface 302 of the transparent laminate film 30. This makes it possible to suppress, for example, discomfort or fatigue felt by a wearer H wearing the face shield 10 due to light reflected on the back surface 302 of the transparent laminate film 30. In addition, the back surface antireflection layer 50 not only suppresses reflection of light incident from the back surface 302 side, but also suppresses reflection of light incident from the front surface 301 side.

As described above, the front-side antireflection layer 40 has the front-side antireflection functional layer 41 and the front-side transparent substrate layer 42. As described above, the back-side antireflection layer 50 has the back-side antireflection functional layer 51 and the back-side transparent substrate layer 52. Here, the front-side transparent substrate layer 42 and the back-side transparent substrate layer 52 will be described first. The front-side antireflection layer 40 and the back-side antireflection layer 50 may have a configuration other than the layer configuration described above, and may each be composed of a resin film. For example, the front-side antireflection layer 40 and the back-side antireflection layer 50 may each use a low-reflection film (FG-10MR1, manufactured by Sharp Corporation). The front-side antireflection layer 40 and the back-side antireflection layer 50 may also have a structure in which irregularities are formed on the surface of the resin provided on the transparent substrate, which is generally known as a moth eye. In this case, a primer layer for improving adhesion may be provided between the transparent substrate and the resin surface. The resin with irregularities may be provided only on one side of the transparent substrate, or may be provided on both sides.

[Front transparent substrate layer and rear transparent substrate layer]
The front transparent substrate layer 42 and the back transparent substrate layer 52 are layers that support, for example, the front antireflection functional layer 41 and the back antireflection functional layer 51, and increase the overall strength of the front antireflection layer 40 and the back antireflection layer 50. The material of the front transparent substrate layer 42 and the back transparent substrate layer 52 is not particularly limited as long as it is a transparent material that is used as a substrate for a general film, but from the viewpoints of material cost, productivity, etc., preferably a plastic film, a plastic sheet, etc. can be appropriately selected depending on the application.

Examples of the plastic film or sheet include those made of various synthetic resins. Examples of the synthetic resin include cellulose resins such as triacetyl cellulose resin (TAC), diacetyl cellulose, acetate butyrate cellulose, and cellophane; polyester resins such as polyethylene terephthalate resin (PET), polybutylene terephthalate resin, polyethylene naphthalate-isophthalate copolymer resin, and polyester-based thermoplastic elastomer; polyolefin resins such as low-density polyethylene resin (including linear low-density polyethylene resin), medium-density polyethylene resin, high-density polyethylene resin, ethylene-α-olefin copolymer, polypropylene resin, polymethylpentene resin, polybutene resin, ethylene-propylene copolymer, propylene-butene copolymer, olefin-based thermoplastic elastomer, and mixtures thereof; acrylic resins such as poly(methyl (meth)acrylate resin, poly(ethyl (meth)acrylate resin, and poly(butyl (meth)acrylate resin); polyamide resins such as nylon 6 or nylon 66; polystyrene resin; polycarbonate resin; polyarylate resin; and polyimide resin. The material of the front transparent substrate layer 42 and the back transparent substrate layer 52 may be a cycloolefin polymer (COP) resin or a cycloolefin copolymer (COC) resin.

The front transparent substrate layer 42 and the back transparent substrate layer 52 can be made of the above-mentioned plastic films and plastic sheets, either alone or in a mixture of two or more of them. From the viewpoints of flexibility, toughness, transparency, etc., however, cellulose resin and polyester resin are more preferable as the materials for the front transparent substrate layer 42 and the back transparent substrate layer 52. From the viewpoints of flexibility, toughness, transparency, etc., the front transparent substrate layer 42 and the back transparent substrate layer 52 preferably contain triacetyl cellulose and polyethylene terephthalate.

There is no particular limit to the thickness of the front transparent substrate layer 42 and the back transparent substrate layer 52, and the thickness is appropriately selected according to the application. The thickness of the front transparent substrate layer 42 and the back transparent substrate layer 52 may be about 5 μm or more and 130 μm or less, and is preferably 10 μm or more and 100 μm or less in consideration of durability and handling. The thickness of each layer can be calculated by measuring the thickness at 20 points from an image of a cross section taken using, for example, a scanning electron microscope (SEM), a transmission electron microscope (TEM), or a scanning transmission electron microscope (STEM), and calculating the average value of the values at the 20 points. When the film thickness to be measured is on the order of μm, it is preferable to use SEM, and when it is on the order of nm, it is preferable to use TEM or STEM. In the case of SEM, it is preferable to set the acceleration voltage to 1 kV or more and 10 kV or less, and the magnification to 1000 times or more and 7000 times or less, and in the case of TEM or STEM, it is preferable to set the acceleration voltage to 10 kV or more and 30 kV or less, and the magnification to 50,000 times or more and 300,000 times or less. The thickness of each layer described below can be measured in the same manner as the thickness of the front transparent substrate layer 42 and the back transparent substrate layer 52.

[Front-surface antireflection functional layer and rear-surface antireflection functional layer]
Next, a description will be given of the front-side antireflection layer 41 and the back-side antireflection layer 51. The front-side antireflection layer 41 and the back-side antireflection layer 51 serve to impart a function of suppressing light reflection to the front-side antireflection layer 40 and the back-side antireflection layer 50, respectively.

The front-side antireflection functional layer 41 may be a coating layer coated on the front-side transparent substrate layer 42, and the back-side antireflection functional layer 51 may be a coating layer coated on the back-side transparent substrate layer 52. In this way, since the front-side antireflection functional layer 41 and the back-side antireflection functional layer 51 are coating layers, the thicknesses of the front-side antireflection functional layer 41 and the back-side antireflection functional layer 51 can be easily controlled, and the desired functions such as the light reflectance and total light transmittance of the transparent laminate film 30 can be easily controlled.

The front-side antireflection functional layer 41 and the back-side antireflection functional layer 51 are preferably made of a cured material containing an acrylic monomer. This makes it possible to form a front-side antireflection functional layer 41 and a back-side antireflection functional layer 51 that are highly uniform even when processed in a short time.

Here, the front-side antireflection functional layer 41 includes the front-side refraction layer 43 and the front-side hard coat layer 44, as described above. Also, the rear-side antireflection functional layer 51 includes the rear-side refraction layer 53 and the rear-side hard coat layer 54, as described above. The front-side hard coat layer 44 may be a coating layer coated on the front-side transparent substrate layer 42, and the front-side refraction layer 43 may be a coating layer coated on the front-side hard coat layer 44. Also, the rear-side hard coat layer 54 may be a coating layer coated on the rear-side transparent substrate layer 52, and the rear-side refraction layer 53 may be a coating layer coated on the rear-side hard coat layer 54. In this way, since the front-side refraction layer 43, the front-side hard coat layer 44, the rear-side refraction layer 53, and the rear-side hard coat layer 54 are coating layers, the thickness of each layer can be easily controlled, and the desired functions such as the light reflectance and total light transmittance of the transparent laminated film 30, and in some cases, the color can be easily controlled.

Next, the front surface hard coat layer 44 and the back surface hard coat layer 54 will be described.

{Front hard coat layer and rear hard coat layer}
The front hard coat layer 44 and the back hard coat layer 54 serve to improve the scratch resistance of the front antireflection layer 40 and the back antireflection layer 50. Here, the hard coat refers to a layer that exhibits a hardness of "H" or more in the pencil hardness test specified in JIS K5600-5-4:1999. The front hard coat layer 44 and the back hard coat layer 54 can be formed, for example, from a hard coat layer coating liquid containing a curable resin composition. Examples of the curable resin composition include a thermosetting resin composition or an ionizing radiation curable resin composition, and from the viewpoint of scratch resistance, an ionizing radiation curable resin composition is preferred.

A thermosetting resin composition is a composition that contains at least a thermosetting resin, and is a resin composition that hardens when heated. Examples of thermosetting resins include acrylic resins, urethane resins, phenolic resins, urea melamine resins, epoxy resins, unsaturated polyester resins, and silicone resins. In a thermosetting resin composition, a curing agent is added to these hardenable resins as necessary.

The ionizing radiation curable resin composition is a composition containing a compound having an ionizing radiation curable functional group (hereinafter, also referred to as "ionizing radiation curable compound"). Examples of the ionizing radiation curable functional group include ethylenically unsaturated bond groups such as (meth)acryloyl groups, vinyl groups, and allyl groups, as well as epoxy groups and oxetanyl groups. As the ionizing radiation curable compound, a compound having an ethylenically unsaturated bond group is preferred, a compound having two or more ethylenically unsaturated bond groups is more preferred, and among them, a polyfunctional (meth)acrylate compound having two or more ethylenically unsaturated bond groups is even more preferred. As the polyfunctional (meth)acrylate compound, either a monomer or an oligomer can be used. Note that, ionizing radiation means electromagnetic waves or charged particle beams that have an energy quantum capable of polymerizing or crosslinking molecules, and usually ultraviolet rays (UV) or electron beams (EB) are used, but other types of electromagnetic waves such as X-rays and gamma rays, charged particle beams such as alpha rays, and ion beams can also be used.

Among the polyfunctional (meth)acrylate compounds, examples of bifunctional (meth)acrylate monomers include ethylene glycol di(meth)acrylate, bisphenol A tetraethoxy diacrylate, bisphenol A tetrapropoxy diacrylate, and 1,6-hexanediol diacrylate. Examples of trifunctional or higher (meth)acrylate monomers include trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol tetra(meth)acrylate, and isocyanuric acid-modified tri(meth)acrylate. The above (meth)acrylate monomers may have a part of the molecular skeleton modified, and those modified with ethylene oxide, propylene oxide, caprolactone, isocyanuric acid, alkyl, cyclic alkyl, aromatic, bisphenol, and the like may also be used.

In addition, examples of the polyfunctional (meth)acrylate oligomer include acrylate polymers such as urethane (meth)acrylate, epoxy (meth)acrylate, polyester (meth)acrylate, and polyether (meth)acrylate. Urethane (meth)acrylate can be obtained, for example, by reacting a polyhydric alcohol and an organic diisocyanate with a hydroxy (meth)acrylate. In addition, preferred epoxy (meth)acrylates are (meth)acrylates obtained by reacting a trifunctional or higher aromatic epoxy resin, alicyclic epoxy resin, aliphatic epoxy resin, or the like with (meth)acrylic acid, (meth)acrylates obtained by reacting a bifunctional or higher aromatic epoxy resin, alicyclic epoxy resin, aliphatic epoxy resin, or the like with a polybasic acid and (meth)acrylic acid, and (meth)acrylates obtained by reacting a bifunctional or higher aromatic epoxy resin, alicyclic epoxy resin, aliphatic epoxy resin, or the like with a phenol and (meth)acrylic acid. The above ionizing radiation curable compounds can be used alone or in combination of two or more.

When the ionizing radiation curable compound is an ultraviolet curable compound, the ionizing radiation curable composition preferably contains additives such as a photopolymerization initiator and a photopolymerization accelerator. The photopolymerization initiator may be one or more selected from acetophenone, benzophenone, α-hydroxyalkylphenone, Michler's ketone, benzoin, benzyl methyl ketal, benzoyl benzoate, α-acyloxime ester, thioxanthones, etc. These photopolymerization initiators preferably have a melting point of 100°C or higher. By setting the melting point of the photopolymerization initiator to 100°C or higher, it is possible to prevent the residual photopolymerization initiator from sublimating due to the heat during the transparent conductive film formation or crystallization process, thereby preventing the reduction in resistance of the transparent conductive film from being impaired. The same applies when using a photopolymerization initiator in the high refractive index layer and low refractive index layer described later. In addition, the photopolymerization accelerator can reduce polymerization inhibition caused by air during curing and increase the curing speed, and examples of such accelerators include one or more selected from p-dimethylaminobenzoic acid isoamyl ester, p-dimethylaminobenzoic acid ethyl ester, etc.

The thickness of the front hard coat layer 44 and the back hard coat layer 54 is preferably in the range of 0.1 μm to 100 μm, and more preferably in the range of 0.8 μm to 20 μm. If the thickness of the front hard coat layer 44 and the back hard coat layer 54 are each within the above range, sufficient hard coat performance is obtained, and the layer is less likely to break when subjected to external impact without cracking.

The refractive index of the front hard coat layer 44 and the back hard coat layer 54 is preferably smaller than that of the front high refractive index layer 46 and the back high refractive index layer 56, more preferably 1.45 to 1.70, and even more preferably 1.45 to 1.60. If the refractive index of the front hard coat layer 44 and the back hard coat layer 54 is in such a range, the front hard coat layer 44 and the back hard coat layer 54 each play the role of a medium refractive index layer. This enables the interference action of the three layers of the front hard coat layer 44, the front high refractive index layer 46, and the front low refractive index layer 45, and the interference action of the three layers of the back hard coat layer 54, the back high refractive index layer 56, and the back low refractive index layer 55. Therefore, light reflection can be effectively suppressed. In addition, from the viewpoint of suppressing interference fringes, it is preferable to reduce the difference between the refractive index of the front hard coat layer 44 and the back hard coat layer 54 and the refractive index of the front transparent substrate layer 42 and the back transparent substrate layer 52.

Methods for imparting the role of a medium refractive index layer to the front hard coat layer 44 and the back hard coat layer 54 include mixing a resin with a high refractive index into the hard coat layer coating solution and mixing particles with a high refractive index. When particles with a high refractive index are mixed, whitening or coating defects may occur due to aggregation of the particles, so the former method (mixing a resin with a high refractive index) is preferred. Examples of resins with a high refractive index include the above-mentioned thermosetting resins or ionizing radiation curable compounds into which groups containing sulfur, phosphorus, or bromine, or aromatic rings, etc. are introduced. As particles with a high refractive index, the same high refractive index particles as those used in the front high refractive index layer 46 and the back high refractive index layer 56 described later can be used.

The refractive index of each layer, such as the front hard coat layer 44 and the back hard coat layer 54, can be calculated, for example, by fitting the reflection spectrum measured by a reflectance photometer to the reflection spectrum calculated from an optical model of a multilayer thin film using Fresnel coefficients.

The front hard coat layer 44 and the back hard coat layer 54 can be formed by preparing a coating solution for forming a hard coat layer using the above-mentioned curable resin composition, additives such as an ultraviolet absorber and a leveling agent, which are blended as necessary, and a diluting solvent, applying the coating solution onto a transparent substrate by a conventionally known coating method, drying, and curing by irradiating with ionizing radiation as necessary.

{Front and rear refraction layers}
Next, the front refraction layer 43 and the rear refraction layer 53 will be described. The front refraction layer 43 and the rear refraction layer 53 play a role in reducing the light reflectance of the front antireflection layer 40 and the rear antireflection layer 50. As described above, the front refraction layer 43 includes the front low refraction layer 45 and the front high refraction layer 46. Also, as described above, the rear refraction layer 53 includes the rear low refraction layer 55 and the rear high refraction layer 56. Here, the front low refraction layer 45 and the rear low refraction layer 55 will be described first. Note that, as shown in FIG. 4A, FIG. 4B, etc., when the front refraction layer 43 and the rear refraction layer 53 are each composed of a single layer, the front refraction layer 43 may be composed only of the front low refraction layer 45, and the rear refraction layer 53 may be composed only of the rear low refraction layer 55.

(Front low refractive index layer and rear low refractive index layer)
The front surface low refractive index layer 45 and the rear surface low refractive index layer 55 are layers provided on the front surface high refractive index layer 46 and the rear surface high refractive index layer 56, and play a role of reducing the light reflectance of the front surface antireflection layer 40 and the rear surface antireflection layer 50 by interference action using the difference in refractive index between the front surface high refractive index layer 46 and the rear surface high refractive index layer 56. In order to make the front surface antireflection layer 40 and the rear surface antireflection layer 50 have an ultra-low reflectance, the front surface low refractive index layer 45 and the rear surface low refractive index layer 55 preferably have a refractive index of 1.26 to 1.40, more preferably 1.28 to 1.38, and even more preferably 1.30 to 1.32. The lower the refractive index of the front surface low refractive index layer 45 and the rear surface low refractive index layer 55, the lower the refractive index of the front surface antireflection layer 40 and the rear surface antireflection layer 50 can be without increasing the refractive index of the front surface high refractive index layer 46 and the rear surface high refractive index layer 56 so much. On the other hand, if the refractive index of the front surface low refractive index layer 45 and the back surface low refractive index layer 55 is too low, the strength of the front surface low refractive index layer 45 and the back surface low refractive index layer 55 tends to decrease. Therefore, by setting the refractive index of the front surface low refractive index layer 45 and the back surface low refractive index layer 55 to the above range, respectively, the amount of high refractive index particles added to the front surface high refractive index layer 46 and the back surface high refractive index layer 56 described later can be reduced while maintaining the strength of the front surface low refractive index layer 45 and the back surface low refractive index layer 55, which is preferable in terms of suppressing color and whitening. In addition, the thickness of the front surface low refractive index layer 45 and the back surface low refractive index layer 55 is preferably 80 nm or more and 120 nm, more preferably 85 nm or more and 110 nm, and even more preferably 90 nm or more and 105 nm. In addition, the front surface low refractive index layer 45 and the back surface low refractive index layer 55 may be formed of a plurality of layers each satisfying the above refractive index range, but from the viewpoint of cost-effectiveness, two layers or less are preferable, and a single layer is more preferable.

The methods for forming the front low refractive index layer 45 and the back low refractive index layer 55 can be broadly divided into wet methods and dry methods. Wet methods include a method of forming the layer by a sol-gel method using metal alkoxides or the like, a method of forming the layer by coating a resin with a low refractive index such as fluororesin, and a method of forming the layer by coating a coating liquid for forming a low refractive index layer in which low refractive index particles are contained in a resin composition. Dry methods include a method of selecting particles having a desired refractive index from the low refractive index particles described below and forming the layer by a physical vapor deposition method or a chemical vapor deposition method. The wet method is superior in terms of production efficiency, and in this embodiment, it is preferable to form the layer by using a coating liquid for forming a low refractive index layer in which low refractive index particles are contained in a resin composition among the wet methods.

Low refractive index particles are preferably used to lower the refractive index, i.e., to improve anti-reflection properties. They can be inorganic, such as silica or magnesium fluoride, or organic, without any restrictions. However, from the viewpoint of further improving anti-reflection properties and ensuring good surface hardness, particles that themselves have a void structure are preferably used.

Particles that have a structure with voids themselves have fine voids inside, and because they are filled with a gas such as air with a refractive index of 1.0, their own refractive index is low. Examples of such void-containing particles include inorganic or organic porous particles and hollow particles, such as porous silica, hollow silica particles, and porous polymer particles and hollow polymer particles using acrylic resin. A preferred example of an inorganic particle is a silica particle with voids prepared using the technology disclosed in JP-A-2001-233611. A preferred example of an organic particle is a hollow polymer particle prepared using the technology disclosed in JP-A-2002-80503. The above-mentioned silica or porous silica with voids has a refractive index in the range of 1.18 to 1.44, which is lower than that of general silica particles, which have a refractive index of about 1.45, and is therefore preferable from the viewpoint of achieving a low refractive index of the front surface low refractive index layer 45 and the back surface low refractive index layer 55.

The hollow silica particles are particles that have the function of lowering the refractive index of the front low refractive index layer 45 and the back low refractive index layer 55 while maintaining the coating strength of the layers. The hollow silica particles used in this embodiment are silica particles with a structure having a cavity inside. The hollow silica particles are silica particles whose refractive index decreases in inverse proportion to the occupancy rate of the internal cavity compared to the inherent refractive index of the silica particles (refractive index n = about 1.45). Therefore, the refractive index of the hollow silica particles as a whole is 1.18 or more and 1.44 or less.

The hollow silica particles are not particularly limited, but examples thereof include particles that have an outer shell and are porous or hollow inside, such as silica particles prepared using the techniques disclosed in JP-A-6-330606, JP-A-7-013137, JP-A-7-133105, and JP-A-2001-233611.

The average particle diameter of the primary particles of the low refractive index particles is preferably 5 nm or more and 200 nm or less, more preferably 5 nm or more and 100 nm or less, and even more preferably 10 nm or more and 80 nm or less. If the average particle diameter of the primary particles is within the above range, the transparency of the front surface low refractive index layer 45 and the back surface low refractive index layer 55 is not impaired, and a good particle dispersion state is obtained. In particular, hollow particles are used as low refractive index particles, and the average particle diameter of the hollow particles is 70 nm or more and 80 nm or less, and it is preferable in that it can increase the porosity and reduce the refractive index while maintaining an outer shell thickness that does not cause insufficient strength, and also has an excellent balance with the ideal thickness (about 100 nm) of the front surface low refractive index layer 45 and the back surface low refractive index layer 55 for reducing reflectance.

The low refractive index particles used in this embodiment are preferably surface-treated. As the surface treatment of the low refractive index particles, surface treatment using a silane coupling agent is more preferable, and among these, surface treatment using a silane coupling agent having a (meth)acryloyl group is preferable. By subjecting the low refractive index particles to a surface treatment, the affinity with the binder resin described below is improved, the particles are uniformly dispersed, and the particles are less likely to aggregate with each other, so that the decrease in transparency of the front low refractive index layer 45 and the back low refractive index layer 55 due to the increase in particle size caused by aggregation, the applicability of the layer-forming composition, and the decrease in the coating strength of the composition are suppressed.

In addition, when the silane coupling agent has a (meth)acryloyl group, the silane coupling agent has ionizing radiation curing properties and therefore easily reacts with the binder resin described below, so that the low refractive index particles are well fixed to the binder resin in the coating film of the layer-forming composition. That is, the low refractive index particles function as a crosslinking agent in the binder resin. This provides a tightening effect for the entire coating film, and makes it possible to impart excellent surface hardness to the front low refractive index layer 45 and the back low refractive index layer 55 while retaining the inherent flexibility of the binder resin. Therefore, the front low refractive index layer 45 and the back low refractive index layer 55 deform by making use of their own flexibility, and therefore have the ability to absorb and restore external impacts, thereby suppressing the occurrence of scratches and providing a high surface hardness with excellent scratch resistance.

Examples of silane coupling agents that are preferably used in the surface treatment of low refractive index particles include 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropyltriethoxysilane, 3-(meth)acryloxypropylmethyldimethoxysilane, 3-(meth)acryloxypropylmethyldiethoxysilane, 2-(meth)acryloxypropyltrimethoxysilane, and 2-(meth)acryloxypropyltriethoxysilane.

The content of low refractive index particles in the front low refractive index layer 45 and the back low refractive index layer 55 is preferably 10 parts by mass or more and 250 parts by mass or less, more preferably 50 parts by mass or more and 200 parts by mass or less, and even more preferably 100 parts by mass or more and 180 parts by mass or less, relative to 100 parts by mass of the resin of the front low refractive index layer 45 and the back low refractive index layer 55, respectively. If the content of low refractive index particles is within the above range, good anti-reflection properties and surface hardness can be obtained. In addition, the proportion of hollow particles and/or porous particles in the total low refractive index particles contained in the front low refractive index layer 45 and the back low refractive index layer 55 is preferably 70% by mass or more, more preferably 80% by mass or more, and even more preferably 80% by mass or more and 95% by mass or less, respectively.

The resin composition contained in the layer-forming coating liquid can be a curable resin composition. As the curable resin composition, the same as those exemplified in the description of the front hard coat layer 44 and the back hard coat layer 54 can be used, and an ionizing radiation curable resin composition is preferable. In addition, as the resin composition, a fluorine-containing polymer or a fluorine monomer that exhibits a low refractive index by itself is also preferably used. A fluorine-containing polymer is a polymer of a polymerizable compound that contains at least a fluorine atom in the molecule, and is preferable in that it can impart antifouling properties and slip properties. The fluorine-containing polymer is preferably one that has a reactive group in the molecule and functions as a curable resin composition, and more preferably one that has an ionizing radiation curable reactive group and functions as an ionizing radiation curable resin composition.

As the fluorine-containing polymer, one that contains silicon together with fluorine is preferred in order not only to repel dirt on the surface of the low refractive index layer, but also to impart wipeability to the repelled dirt. For example, a silicone-containing vinylidene fluoride copolymer in which a silicone component is contained in a copolymer is preferably mentioned. In this case, examples of the silicone component include (poly)dimethylsiloxane, (poly)diethylsiloxane, (poly)diphenylsiloxane, (poly)methylphenylsiloxane, alkyl-modified (poly)dimethylsiloxane, azo-group-containing (poly)dimethylsiloxane, dimethylsilicone, phenylmethylsilicone, alkyl-aralkyl-modified silicone, fluorosilicone, polyether-modified silicone, fatty acid ester-modified silicone, methyl hydrogen silicone, silanol-group-containing silicone, alkoxy-group-containing silicone, phenol-group-containing silicone, methacryl-modified silicone, acrylic-modified silicone, amino-modified silicone, carboxylic acid-modified silicone, carbinol-modified silicone, epoxy-modified silicone, mercapto-modified silicone, fluorine-modified silicone, polyether-modified silicone, etc. Among them, those having a dimethylsiloxane structure are preferred.

The front low refractive index layer 45 and the back low refractive index layer 55 can be formed, for example, by preparing a layer-forming coating liquid using low refractive index particles, a resin composition, additives such as an ultraviolet absorber and a leveling agent that are blended as necessary, and a diluting solvent, and then coating the coating liquid onto the front high refractive index layer 46 or the back high refractive index layer 56 by a conventionally known coating method, drying, and curing by irradiation with ionizing radiation as necessary.

(Front high refractive index layer and rear high refractive index layer)
The front surface high refractive index layer 46 and the back surface high refractive index layer 56 serve to reduce the light reflectance of the front surface antireflection layer 40 and the back surface antireflection layer 50 through an interference effect, utilizing the difference in refractive index between the front surface low refractive index layer 45 and the back surface low refractive index layer 55. The front surface high refractive index layer 46 and the back surface high refractive index layer 56 can each be formed from a layer-forming coating liquid containing, for example, a curable resin composition and high refractive index particles.

It is preferable that the refractive index of the surface high refractive index layer 46 and the back surface high refractive index layer 56 is high from the viewpoint of making the surface antireflection layer 40 and the back surface antireflection layer 50 ultra-low reflectance, but a large amount of high refractive index particles is required to increase the refractive index, which leads to aggregation of the high refractive index particles and causes whitening. For this reason, the refractive index is preferably 1.55 to 1.85, and more preferably 1.56 to 1.70. In addition, the thickness of the surface high refractive index layer 46 and the back surface high refractive index layer 56 is preferably 200 nm or less, and more preferably 50 nm or more and 180 nm or less. In addition, when the surface high refractive index layer 46 and the back surface high refractive index layer 56 each have a two-layer structure described later, it is preferable that the total thickness of the two layers satisfies the above value. In addition, the surface high refractive index layer 46 and the back surface high refractive index layer 56 may be formed from multiple layers that satisfy the above refractive index range, but from the viewpoint of cost-effectiveness, two layers or less are preferable, and a single layer is more preferable.

Examples of high refractive index particles include antimony pentoxide (1.79), zinc oxide (1.90), titanium oxide (2.3 to 2.7), cerium oxide (1.95), tin-doped indium oxide (1.95 to 2.00), antimony-doped tin oxide (1.75 to 1.85), yttrium oxide (1.87), and zirconium oxide (2.10). The numbers in parentheses indicate the refractive index of the material of each particle. Among these high refractive index particles, those with a refractive index of more than 2.0 are preferred from the viewpoint of achieving the above-mentioned suitable refractive index with a small amount of addition. In addition, conductive high refractive index particles such as antimony pentoxide, tin-doped indium oxide (ITO), and antimony-doped tin oxide (ATO) have free electrons whose plasma frequency is in the near-infrared range, and due to the plasma oscillation of the free electrons, some light in the visible light range is absorbed or reflected, making it difficult to suppress the color. For this reason, it is preferable that the high refractive index particles are non-conductive. From the above, titanium oxide and zirconium oxide are preferred among the high refractive index particles exemplified above, and zirconium oxide is the most suitable from the viewpoint of high durability and stability such as light resistance. If it is desired to impart antistatic properties to the front-surface antireflection layer 40 and the back-surface antireflection layer 50, it is preferable to form the front-surface high refractive index layer 46 and the back-surface high refractive index layer 56 into a two-layer structure as described below, and to include conductive high refractive index particles in one of the layers.

The average particle size of the primary particles of the high refractive index particles is preferably 5 nm or more and 200 nm or less, more preferably 5 nm or more and 100 nm or less, and even more preferably 10 nm or more and 80 nm or less. The average particle size of the primary particles of the high refractive index particles and the low refractive index particles described later can be calculated by the following operations (1) to (3).
(1) A surface image of the particles themselves or a dispersion of the particles is coated on a transparent substrate and then dried, and the surface image is taken by SEM, TEM, or STEM.
(2) Randomly extract 10 particles from the surface image, measure the major and minor axes of each particle, and calculate the particle diameter of each particle from the average of the major and minor axes. Note that the major axis is the longest axis on the screen, and the minor axis is the distance between the two points where a line segment perpendicular to the midpoint of the line segment constituting the major axis intersects with the particle.
(3) The same procedure is repeated five times for capturing images of different screens of the same sample, and the value obtained by averaging the particle sizes of a total of 50 particles is regarded as the average particle size.
In addition, when calculating the average particle size of particles, if the calculated average particle size is on the order of μm, it is preferable to use SEM, and if the calculated average particle size is on the order of nm, it is preferable to use TEM or STEM. In the case of SEM, the acceleration voltage is preferably 1 kV to 10 kV and the magnification is preferably 1000 times to 7000 times, and in the case of TEM or STEM, the acceleration voltage is preferably 10 kV to 30 kV and the magnification is preferably 50,000 times to 300,000 times.

From the viewpoint of achieving a balance between increasing the refractive index, suppressing color tone, and suppressing whitening, the content of the high refractive index particles is preferably 30 parts by mass or more and 400 parts by mass or less, more preferably 50 parts by mass or more and 200 parts by mass or less, and even more preferably 80 parts by mass or more and 150 parts by mass or less, relative to 100 parts by mass of the curable resin composition.

The front high refractive index layer 46 and the rear high refractive index layer 56 are preferably dispersion stabilized to suppress excessive aggregation of the high refractive index particles. For example, a means of dispersion stabilization is to add another high refractive index particle having a smaller surface charge than the base high refractive index particle. This allows the base high refractive index particles to gather around the other high refractive index particles in an appropriate amount, suppressing excessive aggregation of the base high refractive index particles. Other means of dispersion stabilization are to use surface-treated high refractive index particles or to add a dispersant to the layer-forming coating liquid.

The curable resin composition for forming the front surface high refractive index layer 46 and the back surface high refractive index layer 56 may be
The same materials as those exemplified in the explanation of the front hard coat layer 44 and the back hard coat layer 54 can be used, and an ionizing radiation curable resin composition is preferable. In order to obtain the above-mentioned refractive index without adding an excessive amount of high refractive index particles, it is preferable to use a curable resin composition with a high refractive index. The refractive index of the curable resin composition is preferably about 1.54 to 1.70.

Here, as described above, the surface high refractive index layer 46 may include a first surface high refractive index layer 47 and a second surface high refractive index layer 48. In this case, it is preferable that the refractive index of the first surface high refractive index layer 47 is higher than that of the second surface high refractive index layer 48. This makes it possible to increase the refractive index difference between the surface high refractive index layer 46 and the surface low refractive index layer 45, reduce the reflectance of the surface anti-reflection layer 40, and reduce the refractive index difference between the surface high refractive index layer 46 and the surface hard coat layer 44, thereby suppressing the occurrence of interference fringes.

As described above, the back surface high refractive index layer 56 may include a first back surface high refractive index layer 57 and a second back surface high refractive index layer 58. In this case, similar to the front surface high refractive index layer 46, it is preferable that the refractive index of the first back surface high refractive index layer 57 is higher than that of the second back surface high refractive index layer 58. This makes it possible to increase the refractive index difference between the back surface high refractive index layer 56 and the back surface low refractive index layer 55, reduce the reflectance of the back surface antireflection layer 50, and reduce the refractive index difference between the back surface high refractive index layer 56 and the back surface hard coat layer 54, thereby suppressing the occurrence of interference fringes.

In addition, when the surface high refractive index layer 46 and the backside high refractive index layer 56 are each made of two layers, the refractive index of the first surface high refractive index layer 47 and the first backside high refractive index layer 57 is preferably 1.60 or more and 1.85 or less, and the refractive index of the second surface high refractive index layer 48 and the second backside high refractive index layer 58 is preferably 1.55 or more and 1.70 or less. Furthermore, in the above two-layer structure, it is preferable that one layer contains conductive high refractive index particles and the other layer contains non-conductive high refractive index particles, and that the thickness of the layer containing conductive high refractive index particles is < the thickness of the layer containing non-conductive high refractive index particles. By adopting this structure, it is possible to impart antistatic properties while suppressing the amount of conductive high refractive index particles added, which may cause coloring. In addition, the conductive high refractive index particles are preferable in that they can be networked within the layer to impart antistatic properties with a small amount of addition, and thus suppress coloring and whitening.

The front high refractive index layer 46 and the back high refractive index layer 56 can be formed by preparing a layer-forming coating solution using high refractive index particles, a curable resin composition, additives such as an ultraviolet absorber and a leveling agent, which are blended as necessary, and a diluting solvent, applying the coating solution onto the front hard coat layer 44 or the back hard coat layer 54 by a conventionally known coating method, drying, and curing by irradiation with ionizing radiation as necessary.

[Transparent adhesive layer, first transparent adhesive layer and second transparent adhesive layer]
The transparent adhesive layers, such as the transparent adhesive layer 31, the first transparent adhesive layer 31a, and the second transparent adhesive layer 31b, are layers for bonding the front-surface antireflection layer 40, the back-surface antireflection layer 50, the core layer 32, and the like to each other. Here, the "transparent adhesive layer" in this specification is a concept including a transparent adhesive layer. The transparent adhesive layer can be formed using various substances that are generally used as adhesives. Examples include acrylic adhesives, urethane adhesives, olefin adhesives, rubber adhesives, silicone adhesives, and polyester adhesives. Acrylic adhesives that have high transparency and can increase adhesive strength are preferred.

Each of the above adhesives can contain various functionalizing agents, stabilizers, etc., to the extent that transparency is not impaired. Also, a tackifier can be added to increase adhesive strength. Also, a crosslinking agent such as isocyanate, epoxy, or a compound containing a double bond can be used to create a crosslinked structure in accordance with each resin.

The transparent adhesive layer can also be formed using an adhesive (OCA, Optical Clear Adhesive) that has a release film laminated on both sides. Commercially available products can also be used, such as the optically transparent adhesive sheet LUCIACS series (manufactured by Nitto Denko Corporation), highly transparent double-sided tape 5400A series (manufactured by Sekisui Chemical Co., Ltd.), optical adhesive sheet Opteria series (manufactured by Lintec Corporation), SANCUARY series (manufactured by San-A Kaken Co., Ltd.), optically transparent adhesive OAD series (manufactured by Toyo Hozai Co., Ltd.), optical coreless double-sided tape RA series (manufactured by Sumiron Co., Ltd.), and Panaclean series PD-S1 (manufactured by Panac Corporation). The adhesive strength of these adhesives is generally 10 N/25 mm or more.

The thickness of the transparent adhesive layer is not particularly limited, but is preferably, for example, 2 μm or more and 200 μm or less. If the thickness of the transparent adhesive layer is 2 μm or more, the front-surface antireflection layer 40 and the back-surface antireflection layer 50 can be reliably bonded, and if the thickness of the transparent adhesive layer is 200 μm or less, transparency (light transmittance) can be maintained. It is more preferable that the lower limit of the thickness of the transparent adhesive layer is 5 μm or more, 10 μm or more, or 15 μm or more, and it is more preferable that the upper limit is 150 μm or less, 160 μm or less, or 170 μm or less.

The method for forming the transparent adhesive layer is not particularly limited, and any known method used in the manufacture of adhesive tapes and the like can be used. Specifically, the transparent adhesive layer can be formed by any method, such as a method in which a coating of an adhesive composition in which each component forming the transparent adhesive layer is dissolved or dispersed in an appropriate organic solvent or water is applied to the surface of the substrate, followed by drying and curing; a method in which each component forming the transparent adhesive layer, a double bond-containing monomer, an oligomer, a crosslinking agent, etc. are applied to the substrate without a solvent, followed by crosslinking with radiation or the like; or an extrusion lamination method.

When using OCA, a transparent adhesive layer can be formed by peeling off the release film on the light release side of the OCA and attaching the adhesive surface to a substrate.

[Core layer]
The core layer 32 plays a role in supporting the front-surface antireflection layer 40 and the back-surface antireflection layer 50. The core layer 32 preferably contains polyethylene terephthalate. Note that the material of the core layer 32 may be the same as the material of the front-surface transparent substrate layer 42 and the back-surface transparent substrate layer 52 described above.

There are no particular limitations on the thickness of the core layer 32, and it is selected appropriately depending on the application. The thickness of the core layer 32 may be about 5 μm or more and 130 μm or less, and considering durability, handling, etc., it is preferable that the thickness is 10 μm or more and 100 μm or less.

[Printed layer]
The printed layer 33 is a layer on which a pattern or the like is printed, and is a layer for improving the design of the transparent laminate film 30. The printed layer 33 may be an ink composition obtained by adjusting an ink composition by adding one or more of ordinary ink vehicles as the main component, optionally adding one or more of plasticizers, stabilizers, antioxidants, light stabilizers, ultraviolet absorbers, curing agents, crosslinking agents, lubricants, antistatic agents, fillers, and other additives as necessary, and further adding a colorant such as a dye or pigment, and thoroughly kneading with a solvent, a diluent, and the like. Examples of such ink vehicles include linseed oil, tung oil, soybean oil, hydrocarbon oil, rosin, rosin ester, rosin-modified resin, shellac, alkyd resin, phenolic resin, maleic acid resin, natural resin, hydrocarbon resin, polyvinyl chloride resin, polyacetic acid resin, polystyrene resin, polyvinyl butyral resin, acrylic or methacrylic resin, polyamide resin, polyester resin, polyurethane resin, epoxy resin, urea resin, melamine resin, aminoalkyd resin, nitrocellulose, ethylcellulose, chlorinated rubber, cyclized rubber, and others, and one or more of these may be used in combination. The printing method may be gravure printing, letterpress printing, screen printing, transfer printing, flexographic printing, inkjet printing, or other printing methods.

The transparent laminate film 30 described above preferably has a thickness of 60 μm or more and 500 μm or less. By making the transparent laminate film 30 thicker than 60 μm, the stiffness and strength required to maintain the shape of the shield portion 30A can be obtained, and therefore droplets of the wearer H's saliva, etc. can be effectively prevented from adhering to the face of another person, and droplets of another person's saliva, etc. can be effectively prevented from adhering to the face of the wearer H. In addition, by making the transparent laminate film 30 thicker than 500 μm, the transparency of the transparent laminate film 30 can be improved.

The transparent laminate film 30 described above preferably has a restoring function. This allows the transparent laminate film 30 to restore to a flat shape when folded or rolled. Here, the restoring function means a function that allows an object (transparent laminate film 30) to restore to a flat shape without forming creases even after the object is bent for a certain period of time.

In the above-mentioned transparent laminate film 30, in the region where the printed layer 33 is not provided, the visual reflectance Y value is preferably 0.0% or more and 2.0% or less, and 0.1% or more and 1.0% or less. In the region where the printed layer 33 is not provided, the visual reflectance Y value is 0.0% or more and 2.0% or less, so that the region where the printed layer 33 is not provided in the transparent laminate film 30 can be made inconspicuous and the printed layer 33 can be made conspicuous. In this way, by making the region where the printed layer 33 is not provided inconspicuous, the observer who views the printed layer 33 can be given the impression that the character formed by the printed layer 33 is floating in the air. In addition, depending on the angle at which the observer views the printed layer 33, the observer can be given the impression that the character is directly printed on the face F. The face shield 10 according to this embodiment can display a design different from the conventional one. Therefore, the design of the face shield can be improved.

The luminous reflectance Y value can be measured by the following method. First, light is irradiated onto the front surface 301 or rear surface 302 of the transparent laminate film 30 so that the angle of incidence is 5°. Then, the luminous reflectance Y value can be measured based on the specularly reflected light of the incident light. Here, in this specification, the luminous reflectance Y value refers to the luminous reflectance Y value of the CIE 1931 standard color system.

In addition, in the area where the printed layer 33 is not provided, the transparent laminate film 30 preferably has a reflectance of 2% or less for light with a wavelength of 550 nm, and a total light transmittance (JIS K7361-1:1997) of 90% or more. Furthermore, the transparent laminate film 30 more preferably has a total light transmittance of 92% or more. Furthermore, the transparent laminate film 30 preferably has a haze (JIS K7136:2000) of 3.0% or less, more preferably 2.5% or less, and even more preferably 2.0% or less.

The transparent laminate film 30 described above preferably has a transmittance of 1% or less in the ultraviolet region with a wavelength of 380 nm or less in the area where the printed layer 33 is not provided. This makes it possible to prevent the wearer H from getting sunburned even if the wearer H wearing the face shield 10 works in an environment exposed to direct sunlight.

In the above-mentioned transparent laminate film 30, the arithmetic mean roughness Ra (JIS B0601:1994) of the front surface 301 and the back surface 302 is preferably 10 nm or less, and more preferably 1 nm or more and 8 nm or less. In addition, the ten-point mean roughness Rz (JIS B0601:1994) of the front surface 301 and the back surface 302 is preferably 160 nm or less, and more preferably 50 nm or more and 155 nm or less. If Ra and Rz are in the above ranges, the film has smoothness and improved scratch resistance.

Next, a method for producing the transparent laminate film, the transparent laminate film with a protective film, and the face shield according to the present embodiment will be described. First, a method for producing the transparent laminate film 30 will be described.

First, the surface antireflection layer 40 is prepared. In this case, for example, a resin film constituting the surface transparent substrate layer 42 is first prepared. Next, a coating liquid for forming a hard coat layer is applied onto the resin film, dried and irradiated with ultraviolet light to form a surface hard coat layer 44. Next, a coating liquid for forming a high refractive index layer is applied onto this surface hard coat layer 44, dried and irradiated with ultraviolet light to form a surface high refractive index layer 46. Next, a coating liquid for forming a low refractive index layer is applied onto this surface high refractive index layer 46, dried and irradiated with ultraviolet light to form a surface low refractive index layer 45. In this manner, the surface antireflection layer 40 can be obtained.

The back surface antireflection layer 50 is also prepared. In this case, for example, first, a resin film constituting the back surface transparent substrate layer 52 is prepared. Next, a coating liquid for forming a hard coat layer is applied onto the resin film, dried and irradiated with ultraviolet light to form a back surface hard coat layer 54. Next, a coating liquid for forming a high refractive index layer is applied onto this back surface hard coat layer 54, dried and irradiated with ultraviolet light to form a back surface high refractive index layer 56. Next, a coating liquid for forming a low refractive index layer is applied onto this back surface high refractive index layer 56, dried and irradiated with ultraviolet light to form a back surface low refractive index layer 55. In this manner, the back surface antireflection layer 50 can be obtained.

Furthermore, a core layer 32 having a printed layer 33 is prepared. In this case, for example, a polyethylene terephthalate film is first prepared as the core layer 32. Next, the printed layer 33 is formed on the core layer 32 by, for example, gravure printing.

Then, the front surface antireflection layer 40 and the core layer 32 are bonded to each other via the first transparent adhesive layer 31a, and the core layer 32 and the rear surface antireflection layer 50 are bonded to each other via the second transparent adhesive layer 31b to produce the transparent laminate film 30. In this manner, the transparent laminate film 30 can be produced.

Next, a surface protective film 61 is attached to the surface 301 of the obtained transparent laminate film 30, and a back protective film 62 is attached to the back surface 302. At this time, the surface protective film 61 and the back protective film 62 may each include a bonding layer not shown, and be attached to the transparent laminate film 30 by this bonding layer. In this manner, the transparent laminate film 60 with a protective film can be produced. Note that the surface protective film 61 and the back protective film 62 may be attached separately to the surface antireflection layer 40 and the back antireflection layer 50, respectively, before the surface antireflection layer 40 and the back antireflection layer 50 are bonded to each other via the transparent adhesive layer 31.

Next, the face shield 10 is made.

In this case, the transparent laminate film 60 with the protective film is first processed into a predetermined shape. In this case, the transparent laminate film 60 with the protective film may be processed by punching using a die, cutting using a drill, or laser processing using a laser. From the viewpoint of processing speed and productivity, it is preferable that the transparent laminate film 60 with the protective film is processed by punching.

Next, the front protective film 61 and the back protective film 62 are removed from the transparent laminate film 60 with protective film that has been processed into a predetermined shape. This results in the transparent laminate film 30 that has been processed into a predetermined shape.

Next, the transparent laminate film 30 processed into a predetermined shape is attached to the holding member 20 to obtain the face shield 10 shown in Figure 1.

As described above, according to the present embodiment, the transparent laminate film 30 includes at least the core layer 32 and the printing layer 33 that is provided on one surface of the core layer 32 and covers a part of the core layer 32. In addition, in the area where the printing layer 33 is not provided, the luminous reflectance Y value is 0.0% or more and 2.0% or less. As a result, in the transparent laminate film 30, the area where the printing layer 33 is not provided can be made inconspicuous, and the printing layer 33 can be made conspicuous. In this way, by making the area where the printing layer 33 is not provided inconspicuous, it is possible to give the observer who views the printing layer 33 the impression that the character or the like formed by the printing layer 33 is floating in the air. In addition, in the area where the printing layer 33 is not provided, the luminous reflectance Y value is 0.0% or more and 2.0% or less, it is possible to suppress the printing layer 33 from becoming difficult to see due to reflected light. Furthermore, depending on the angle at which the observer views the printing layer 33, it is possible to give the observer the impression that the character or the like is directly printed on the face F. The face shield 10 according to this embodiment can display a design different from conventional designs. This improves the design of the face shield 10. In addition, because the printed layer 33 can be made to stand out, text and symbol information can be clearly displayed on the face shield 10.

In addition, according to this embodiment, the transparent laminate film 30 has a reflectance of 2% or less for light with a wavelength of 550 nm in areas where the printed layer 33 is not provided, and a total light transmittance of 90% or more. This makes it possible to make the areas where the printed layer 33 is not provided even less noticeable. It also improves the visibility of the face F of the wearer H.

In addition, according to this embodiment, in the area where the printing layer 33 is not provided, the transmittance of ultraviolet light with a wavelength of 380 nm or less is 1% or less. This makes it possible to prevent the wearer H from getting sunburned even if the wearer H wearing the face shield 10 works in an environment where he or she is exposed to direct sunlight.

Furthermore, according to this embodiment, the core layer 32 contains polyethylene terephthalate. This can improve the transparency of the core layer 32.

In addition, according to this embodiment, the transparent laminate film 30 is provided on one side of the core layer 32 and further includes a front surface antireflection layer 40 constituting the front surface 301, and a rear surface antireflection layer 50 provided on the other side of the core layer 32 and constituting the rear surface 302. This makes it possible to suppress the reflection of light incident from the front surface 301 side of the transparent laminate film 30 and the reflection of light incident from the rear surface 302 side of the transparent laminate film 30. That is, while improving the visibility when the transparent laminate film 30 is viewed from the front surface 301 side, it is possible to improve the visibility when the transparent laminate film 30 is viewed from the rear surface 302 side. This makes it possible to improve the visibility of the face F of the wearer H when, for example, a wearer H wearing the face shield 10 is viewed. Therefore, it is possible to improve the visibility of the mouth of the wearer H, and to facilitate smooth communication between the wearer H and others. In addition, for example, a wearer H wearing a face shield 10 having a shield portion 30A made from a transparent laminate film 30 can be prevented from feeling discomfort or fatigue due to light reflected on the back surface 302 of the transparent laminate film 30.

In addition, the transparent laminate film 30 described above can provide the following effects.
No deterioration occurs even after 100 alcohol wipes and disinfection.
Letters written with oil-based ink can be easily wiped off.
Even when rubbed with an H pencil 100 times, the surface is prevented from being scratched.
Adherent fingerprints can be wiped off without leaving any traces.
The fact that the above-mentioned effects can be achieved will be explained in the examples described later.

In addition, according to this embodiment, the transparent laminate film 30 further includes a first transparent adhesive layer 31a that bonds the front-surface antireflection layer 40 and the core layer 32, and a second transparent adhesive layer 31b that bonds the core layer 32 and the back-surface antireflection layer 50. This makes it easy to produce a transparent laminate film 30 that includes the core layer 32 located between the front-surface antireflection layer 40 and the back-surface antireflection layer 50.

In addition, according to this embodiment, the first transparent adhesive layer 31a and the second transparent adhesive layer 31b each contain an acrylic adhesive. As a result, when a transparent laminate film 30 is produced that includes a front-side antireflection layer 40 constituting the front surface 301, a rear-side antireflection layer 50 constituting the rear surface 302, and a core layer 32, it is possible to obtain a transparent laminate film 30 that maintains transparency and has good optical properties.

According to this embodiment, the front-side antireflection layer 40 has a front-side antireflection functional layer 41 and a front-side transparent substrate layer 42 arranged in this order from the front side 301 to the back side 302. The back-side antireflection layer 50 has a back-side antireflection functional layer 51 and a back-side transparent substrate layer 52 arranged in this order from the back side 302 to the front side 301. This makes it possible to increase the overall strength of the front-side antireflection layer 40 and the back-side antireflection layer 50 while imparting the function of suppressing light reflection to the front-side antireflection layer 40 and the back-side antireflection layer 50.

In addition, according to this embodiment, the front-side antireflection functional layer 41 is a coating layer coated on the front-side transparent substrate layer 42, and the back-side antireflection functional layer 51 is a coating layer coated on the back-side transparent substrate layer 52. In this way, since the front-side antireflection functional layer 41 and the back-side antireflection functional layer 51 are coating layers, the thicknesses of the front-side antireflection functional layer 41 and the back-side antireflection functional layer 51 can be easily controlled, and desired functions such as the light reflectance and total light transmittance of the transparent laminate film 30 can be easily controlled.

In addition, according to this embodiment, the front-side antireflection functional layer 41 and the back-side antireflection functional layer 51 are each made of a cured material containing an acrylic monomer. This makes it possible to form a front-side antireflection functional layer 41 and a back-side antireflection functional layer 51 that are highly uniform even with short processing times. In addition, it is possible to achieve both high hardness and good optical performance.

According to this embodiment, the front-side antireflection layer 41 includes a front-side refraction layer 43 and a front-side hard coat layer 44 arranged in this order from the front side 301 to the back side 302. The back-side antireflection layer 51 includes a back-side refraction layer 53 and a back-side hard coat layer 54 arranged in this order from the back side 302 to the front side 301. This can improve the scratch resistance of the front-side antireflection layer 40 and the back-side antireflection layer 50 while reducing the light reflectance of the front-side antireflection layer 40 and the back-side antireflection layer 50.

According to this embodiment, the front hard coat layer 44 is a coating layer coated on the front transparent substrate layer 42, the front refraction layer 43 is a coating layer coated on the front hard coat layer 44, the back hard coat layer 54 is a coating layer coated on the back transparent substrate layer 52, and the back refraction layer 53 is a coating layer coated on the back hard coat layer 54. In this way, since the front refraction layer 43, the front hard coat layer 44, the back refraction layer 53, and the back hard coat layer 54 are coating layers, the thickness of each layer can be easily controlled, and the desired functions such as the light reflectance and total light transmittance of the transparent laminate film 30 can be easily controlled.

According to this embodiment, the surface refraction layer 43 includes a surface low refractive index layer 45 and a surface high refractive index layer 46 arranged in order from the surface 301 to the back surface 302. The back surface refraction layer 53 includes a back surface low refractive index layer 55 and a back surface high refractive index layer 56 arranged in order from the back surface 302 to the surface 301. This makes it possible to more effectively reduce the light reflectance of the surface antireflection layer 40 and the back surface antireflection layer 50 by interference using the difference in refractive index between the surface low refractive index layer 45 and the surface high refractive index layer 46, and the difference in refractive index between the back surface low refractive index layer 55 and the back surface high refractive index layer 56.

According to this embodiment, the surface high refractive index layer 46 includes a first surface high refractive index layer 47 and a second surface high refractive index layer 48 arranged in order from the surface 301 to the back surface 302. The back surface high refractive index layer 56 includes a first back surface high refractive index layer 57 and a second back surface high refractive index layer 58 arranged in order from the back surface 302 to the surface 301. This makes it possible to more effectively reduce the light reflectance of the surface antireflection layer 40 and the back surface antireflection layer 50 by interference using the difference in refractive index between the surface low refractive index layer 45 and the surface high refractive index layer 46, and the difference in refractive index between the back surface low refractive index layer 55 and the back surface high refractive index layer 56.

In addition, according to this embodiment, the refractive index of the first surface high refractive index layer 47 is higher than that of the second surface high refractive index layer 48. In addition, the refractive index of the first back surface high refractive index layer 57 is higher than that of the second back surface high refractive index layer 58. This makes it possible to increase the refractive index difference between the surface high refractive index layer 46 and the surface low refractive index layer 45, reduce the reflectance of the front surface antireflection layer 40, and reduce the refractive index difference between the surface high refractive index layer 46 and the front surface hard coat layer 44, thereby suppressing the occurrence of interference fringes. In addition, the refractive index difference between the back surface high refractive index layer 56 and the back surface low refractive index layer 55 can be increased, the reflectance of the back surface antireflection layer 50 can be reduced, and the refractive index difference between the back surface high refractive index layer 56 and the back surface hard coat layer 54 can be reduced, thereby suppressing the occurrence of interference fringes.

In addition, according to this embodiment, the front transparent substrate layer 42 and the back transparent substrate layer 52 contain triacetyl cellulose or polyethylene terephthalate. This can improve the transparency of the front transparent substrate layer 42 and the back transparent substrate layer 52. In addition, when the front transparent substrate layer 42 and the back transparent substrate layer 52 contain triacetyl cellulose, the flexibility of the front transparent substrate layer 42 and the back transparent substrate layer 52 can also be effectively improved. Therefore, when the shield part 30A made from the transparent laminated film 30 is folded, it is possible to suppress the occurrence of creases, scratches, etc. in the shield part 30A. In addition, even if the size of the shield part 30A is increased, it is possible to suppress the occurrence of creases, scratches, etc. in the shield part 30A. Therefore, since the front transparent substrate layer 42 and the back transparent substrate layer 52 contain triacetyl cellulose, it is possible to easily produce a large-sized shield part 30A.

In addition, according to this embodiment, the transparent laminate film 30 has a restoring function. As a result, even if the transparent laminate film 30 is folded or rolled, the transparent laminate film 30 can be restored to a flat shape without causing creases or scratches on the transparent laminate film 30.

Furthermore, according to this embodiment, the transparent laminate film 30 is used in a face shield 10 that protects the face F of the wearer H. This makes it possible to easily obtain a face shield 10 that can improve the visibility of the face F of the wearer H while suppressing the wearer H from feeling uncomfortable or tired. Furthermore, as described above, the face shield 10 according to this embodiment can display a design different from conventional designs, thereby improving the design of the face shield.

Furthermore, according to this embodiment, the transparent laminate film 60 with protective film includes the transparent laminate film 30 according to this embodiment, a surface protective film 61 that protects the surface 301 of the transparent laminate film 30, and a back protective film 62 that protects the back surface 302 of the transparent laminate film 30. This makes it possible to prevent the surface 301 and back surface 302 of the transparent laminate film 30 from being scratched when the transparent laminate film 30 is processed. In addition, it makes it possible to prevent the surface 301 and back surface 302 from being contaminated by foreign matter or the like when the transparent laminate film 30 is shipped and transported.

In the above embodiment, the holding member 20 of the face shield 10 is a so-called eyeglass frame type, but the present invention is not limited to this. For example, the holding member 20 may be a so-called hair band type or headband type. In this case, as shown in FIG. 5, the holding member 20 may have a band 25 that circumferentially covers the head of the wearer H. The material of the band 25 may be an elastic body such as rubber, in addition to resin or cardboard. Furthermore, the holding member 20 may have a protective member 26 that is attached to the band 25 and abuts against the forehead of the wearer H. It is preferable that the protective member 26 contains a material having cushioning properties such as sponge. This can prevent the wearer H wearing the face shield 10 from feeling uncomfortable. In the illustrated example, the band 25 covers only a part of the head of the wearer H, but the band 25 may cover the entire circumference of the head of the wearer H.

In the above-described embodiment, the shield part 30A covers the entire face F of the wearer H, but the present invention is not limited to this. For example, as shown in FIG. 6, the shield part 30A (transparent laminate film 30) may cover only a part of the face F of the wearer H. In this case, the holding member 20 may have a chin pad 27 that abuts against the chin J of the wearer H, and a pair of hook parts 28 (only one of which is shown in FIG. 6) that are connected to the chin pad 27 and hooked on the ears E of the wearer H. The material of the chin pad 27 may be resin, cardboard, or the like. The hook parts 28 may be a string-like member, and the material of the hook parts 28 may be an elastic body such as rubber. In this modified example, the shield part 30A covers the mouth M and nose N of the wearer H. This can prevent droplets of saliva and other fluids from sneezing or coughing from landing on the face of others, and can improve visibility of the mouth of the wearer H, facilitating smooth communication between the wearer H and others. Note that the shield part 30A may cover only the area near the mouth M of the wearer H, without covering the nose N.

In the above-mentioned embodiment, the transparent laminate film 30 is used in a face shield 10 that protects the face F of the wearer H, but the present invention is not limited to this. For example, as shown in FIG. 7, the transparent laminate film 30 may be attached to a pair of temple parts 21 as an accessory. In this case, as shown in FIG. 8, a pair of through holes 35 may be formed in the transparent laminate film 30, and the temple parts 21 may be inserted into the through holes 35 to attach the transparent laminate film 30 to the temple parts 21. In this modification, the width (horizontal distance in FIG. 8) of the transparent laminate film 30 may be about 50 mm, and the length (vertical distance in FIG. 8) may be about 200 mm.

Next, we will describe a specific example of the above embodiment.

Example 1
First, the transparent laminated film 30 shown in FIG. 4A was produced. At this time, the surface antireflection layer 40 was produced first. When producing the surface antireflection layer 40, a triacetyl cellulose film (refractive index 1.49) having a thickness of 60 μm was prepared as the surface transparent substrate layer 42. Next, a hard coat layer forming coating liquid having the following formulation was applied on the triacetyl cellulose film, dried and irradiated with ultraviolet light to form a surface hard coat layer 44 having a thickness of 10 μm, a refractive index of 1.54, and a pencil hardness of 2H. Next, a high refractive index layer forming coating liquid having the following formulation was applied on the surface hard coat layer 44, dried and irradiated with ultraviolet light to form a surface high refractive index layer 46 having a thickness of 150 nm and a refractive index of 1.63. Next, a low refractive index layer forming coating liquid having the following formulation was applied on the surface high refractive index layer 46, dried and irradiated with ultraviolet light to form a surface low refractive index layer 45 having a thickness of 100 nm and a refractive index of 1.30, thereby obtaining a surface antireflection layer 40.

<Preparation of Coating Solution for Forming Hard Coat Layer>
1.6 parts by mass of photopolymerization initiator (BASF, Irgacure 127, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methylpropionyl)benzyl]phenyl}-2-methylpropan-1-one) and 58.3 parts by mass of dilution solvent (methyl isobutyl ketone / cyclohexanone = 8/2) were added and stirred until there was no residue left. 20 parts by mass of photocurable resin (Arakawa Chemical, Beam Set 577) and 20 parts by mass of high refractive index resin (DIC, Polylight RX-4800) were added and stirred until there was no residue left. Finally, 0.1 parts by mass of leveling agent (Dainichiseika Chemicals, Seikabeam 10-28 (MB)) was added and stirred to prepare a coating solution for forming a hard coat layer.

<Preparation of Coating Solution for Forming High Refractive Index Layer>
0.1 parts by mass of photopolymerization initiator (manufactured by BASF, Irgacure 127) and 92.6 parts by mass of dilution solvent (methyl isobutyl ketone / cyclohexanone / methyl ethyl ketone = 4 / 2 / 4) were added and stirred until there was no residue left. 1.25 parts by mass of photocurable resin (manufactured by Arakawa Chemical Co., Ltd., Beam Set 577) were added thereto and stirred until there was no residue left. Furthermore, 6 parts by mass of zirconium oxide (manufactured by Sumitomo Osaka Cement Co., Ltd., MZ-230X, solid content 32.5 mass%, average primary particle size 15 to 50 nm) and 0.05 parts by mass of leveling agent (manufactured by Dainichiseika Chemicals Co., Ltd., Seikabeam 10-28 (MB)) were added and stirred, respectively, to prepare a coating liquid for forming a high refractive index layer.

<Preparation of Coating Solution for Forming Low Refractive Index Layer>
0.2 parts by mass of photopolymerization initiator (manufactured by BASF, Irgacure 127) and 91.1 parts by mass of dilution solvent (MIBK/AN=7/3) were added and stirred until there was no remaining residue. 1.0 parts by mass of photocurable resin (manufactured by Nippon Kayaku Co., Ltd., KAYARAD-PET-30), 7.6 parts by mass of hollow silica particles (solid content 20% by mass, average primary particle diameter 60 nm), and 0.1 parts by mass of leveling agent (manufactured by Dainichiseika Chemicals Co., Ltd., Seikabeam 10-28 (MB)) were added and stirred to prepare a coating liquid for forming a low refractive index layer.

Next, the back surface antireflection layer 50 was prepared. When preparing the back surface antireflection layer 50, first, a triacetyl cellulose film (refractive index 1.49) having a thickness of 60 μm was prepared as the back surface transparent substrate layer 52. Next, the hard coat layer forming coating liquid of the above formulation was applied onto the triacetyl cellulose film, dried and irradiated with ultraviolet light to form a back surface hard coat layer 54 having a thickness of 10 μm, a refractive index of 1.54, and a pencil hardness of 2H. Next, the high refractive index layer forming coating liquid of the above formulation was applied onto this back surface hard coat layer 54, dried and irradiated with ultraviolet light to form a back surface high refractive index layer 56 having a thickness of 150 nm and a refractive index of 1.63. Next, the low refractive index layer forming coating liquid of the above formulation was applied onto this back surface high refractive index layer 56, dried and irradiated with ultraviolet light to form a back surface low refractive index layer 55 having a thickness of 100 nm and a refractive index of 1.30, thereby obtaining the back surface antireflection layer 50.

In parallel with the production of the front-side antireflection layer 40 and the back-side antireflection layer 50, a 12 μm-thick polyethylene terephthalate film (refractive index 1.58-1.70) on which the printing layer 33 was formed was prepared as the printing layer 33 and the core layer 32.

Next, the front-surface antireflection layer 40 and the core layer 32 on which the printed layer 33 was formed were bonded together via a first transparent adhesive layer 31a (Panaclean series PD-S1, manufactured by Panac Corporation, thickness 25 μm), and the core layer 32 on which the printed layer 33 was formed and the rear-surface antireflection layer 50 were bonded together via a second transparent adhesive layer 31b (Panaclean series PD-S1, manufactured by Panac Corporation, thickness 25 μm) to produce a transparent laminate film 30. The layer structure of the obtained transparent laminate film 30 is as follows.
Low flex/High flex/Hard coat/TAC/Adhesive/Printed/PET/Adhesive/TAC/Hard coat/High flex/Low flex In the above, "low flex" means a low refractive index layer on the front surface or a low refractive index layer on the back surface (same below). "High flex" means a high refractive index layer on the front surface or a high refractive index layer on the back surface (same below). "Hard coat" means a hard coat layer on the front surface or a hard coat layer on the back surface (same below). "TAC" means a triacetyl cellulose film (same below). "Adhesive" means a transparent adhesive layer (same below). "Printed" means a printed layer (same below). "PET" means a polyethylene terephthalate film (same below).

(1) Reflectance Measurement Test Next, a reflectance measurement test was performed on the transparent laminate film 30.

At this time, first, a sample of 20 mm x 20 mm size was cut out from an area of the obtained transparent laminate film 30 where the printing layer 33 was not provided. Next, light was irradiated onto the surface of the sample so that the angle of incidence was 85° (a surface parallel to the film surface is considered to be 0°; the same applies below). Then, a spectrophotometer (V-7100, manufactured by JASCO Corporation) was used to calculate the luminous reflectance Y value from the reflection spectrum. At this time, the wavelengths of light were set to 450 nm, 550 nm, and 650 nm, and light was irradiated onto the surface of the sample for each wavelength. Then, the reflection spectrum of the light was measured using a spectrophotometer (V-7100, manufactured by JASCO Corporation), and the reflectance of the light at each wavelength was calculated.

(2) Design Evaluation Test In addition, a design evaluation test of the face shield 10 was conducted.

First, the face shield 10 shown in FIG. 1 was produced using the obtained transparent laminate film 30. Next, the printed layer 33 of the face shield 10 was observed, and the design of the face shield was evaluated.

(3) Transmittance Measurement Test The transparent laminate film 30 was subjected to a transmittance measurement test.

First, a sample measuring 20 mm x 20 mm was cut out from the obtained transparent laminate film 30. Next, light was irradiated onto the surface of the sample at an incident angle of 85°. The wavelengths of the light were 450 nm, 550 nm, and 650 nm, and the surface of the sample was irradiated with light of each wavelength. Then, the light transmission spectrum was measured using a spectrophotometer (V-7100, manufactured by JASCO Corporation), and the light transmittance at each wavelength was calculated.

(4) Wearability Evaluation Test A wearability evaluation test of the face shield 10 was also carried out.

First, the obtained transparent laminate film 30 was used to produce the face shield 10 shown in FIG. 1. Next, five experimenters were randomly selected from men and women aged 22 or older. The five selected experimenters then performed office work while wearing the face shield 10. After that, the five experimenters who had performed office work for one hour were interviewed about whether or not they had any impression of wearing the face shield 10.

(5) Visibility Evaluation Test Also, a visibility evaluation test of the face shield 10 was conducted.

First, the face shield 10 shown in FIG. 1 was produced using the obtained transparent laminate film 30. Next, five experimenters were randomly selected from men and women aged 22 years or older. The visibility of the facial expressions of the five experimenters wearing the face shield 10 was then confirmed. In this case, the experimenters' facial expressions were observed from a distance of about 1 to 2 m from the experimenter in a typical indoor environment illuminated by fluorescent lights. In addition, the observer observed the experimenter's facial expression while moving about 20° left and right around the surface 301 of the face shield 10 from a position facing the experimenter directly.

(6) Drop Strength Evaluation Test A drop strength evaluation test of the face shield 10 was also conducted.

First, the face shield 10 shown in FIG. 1 was produced using the obtained transparent laminate film 30. Next, a drop test was performed on the face shield 10. First, one of the temple portions 21 of the holding member 20 of the face shield 10 was pinched, and the face shield 10 was lifted up so that the temple portion 21 was 170 mm above the ground. The face shield 10 was then allowed to freely fall to the ground. In this manner, the drop test was performed on the face shield 10. Then, this drop test was repeated 10 times to check whether there was any change in the appearance of the face shield 10.

(7) Scratch Resistance Evaluation Test Also, a scratch resistance evaluation test of the transparent laminate film 30 was carried out.

First, the obtained transparent laminate film 30 was pinched with fingers to leave a fingerprint on the transparent laminate film 30. Next, the fingerprint was wiped off with Kimwipe S-200 (product name). The fingerprint was wiped off with Kimwipe S-200 in a dry state without impregnating the Kimwipe S-200 with any chemicals such as alcohol. This test was repeated three times to check whether the transparent laminate film 30 had any scratches after the fingerprints were wiped off. In each test, the fingerprint was left in the same position by pinching approximately the same part of the transparent laminate film 30 with fingers.

In addition, when the transparent laminate film 30 was rubbed with a pencil, it was confirmed whether the transparent laminate film 30 was scratched or not. At this time, the core of a pencil with hardness H was pushed out by about 5 mm, and the bottom surface of the core was flattened by rubbing with sandpaper. Next, the pencil was rubbed against the transparent laminate film 30 while tilting the pencil against the surface 301 so that the angle between the bottom surface of the core and the surface 301 of the transparent laminate film 30 was about 45°. In addition, when the pencil was rubbed against the transparent laminate film 30, the pencil was rubbed against the transparent laminate film 30 so that the pencil moved a distance of about 3 cm and the amount of indentation of the surface 301 of the face shield 10 was about 5 mm to about 10 mm. Then, such a test was repeated 100 times, and it was confirmed whether the transparent laminate film 30 was scratched or not after the pencil was rubbed.

(8) Alcohol Resistance Evaluation Test Also, an alcohol resistance evaluation test of the transparent laminate film 30 was carried out.

First, the surface 301 of the transparent laminate film 30 was wiped with Kimwipe S-200 (product name) sufficiently saturated with ethanol. The surface 301 of the transparent laminate film 30 was wiped so that the Kimwipe S-200 came into contact with the edge surface located between the surface 301 and the back surface 302 of the transparent laminate film 30. This test was then repeated 100 times to check whether there was any change in the appearance of the transparent laminate film 30.

(9) Droplet Prevention Functionality Evaluation Test Also, a splash prevention functionality evaluation test of the transparent laminate film 30 was carried out.

First, an alcohol spray bottle (capacity 30 ml) was filled with colored ink (Shachihata refill ink (XLR-20N red 20 ml for Capless 9 and X stampers)). Next, an A3 piece of paper was attached to the wall. Next, the experimenter wearing a face shield 10 faced the wall at a distance of 50 cm. Next, a spray was placed between the experimenter's mouth and the face shield 10 so that the nozzle of the spray faced the wall. After that, the colored ink was sprayed from the spray. After spraying, it was confirmed whether the colored ink had adhered to the paper attached to the wall.

(10) UV Transmittance Measurement Test Also, a UV transmittance measurement test of the transparent laminate film 30 was carried out.

In this case, the UV transmittance measurement test was carried out in the same manner as the transmittance measurement test described above, except that the wavelength of the irradiated light was 380 nm.

(11) Antifouling Property Evaluation Test Also, an antifouling property evaluation test of the transparent laminate film 30 was carried out.

At this time, first, a line is drawn on the surface 301 of the obtained transparent laminate film 30 with an oil-based marker,
Immediately afterwards, the fingerprints were wiped off with Kimwipe S-200 (trade name). At this time, the Kimwipe S-200 was not impregnated with any chemical such as alcohol, and the fingerprints were wiped off with the dry Kimwipe S-200.

Example 2
A commercially available low-reflection film (manufactured by Sharp Corporation, FG-10MR1) was used, and the low-reflection film and the core layer 32 on which the printed layer 33 was formed were bonded to each other via a first transparent adhesive layer 31a (manufactured by Panac Corporation, Panaclean series PD-S1, thickness 25 μm). A commercially available low-reflection film (manufactured by Sharp Corporation, FG-10MR1) was bonded to the surface of the core layer 32 on which the low-reflection film was not bonded via a second transparent adhesive layer 31b (manufactured by Panac Corporation, Panaclean series PD-S1, thickness 25 μm). The same procedures as in Example 1 were performed except that a reflectance measurement test, a design evaluation test, a transmittance measurement test, a wearability evaluation test, a visibility evaluation test, a drop strength evaluation test, a scratch resistance evaluation test, an alcohol resistance evaluation test, a splash prevention functionality evaluation test, a UV transmittance measurement test, and an antifouling evaluation test were performed.

Here, a cross section of the low-reflection film of Example 2 was analyzed with an SEM, and it was found to have a three-layer structure consisting of a 187 μm thick resin layer and two resin layers, each 2 to 3 μm thick and with irregularities on the surface side, stacked on top and bottom.

(Comparative Example 1)
A reflectance measurement test, a design evaluation test, a transmittance measurement test, a wearability evaluation test, a visibility evaluation test, a drop strength evaluation test, a scratch resistance evaluation test, an alcohol resistance evaluation test, a splash prevention functionality evaluation test, a UV transmittance measurement test, and an antifouling evaluation test were performed in the same manner as in Example 1, except that a commercially available transparent film (YF-800L (product name) manufactured by Yamamoto Kogaku Co., Ltd.) and a core layer on which a printed layer was formed were adhered to each other via a transparent adhesive layer (Panac Clean Series PD-S1 manufactured by Panac Corporation, thickness 25 μm).

Here, when the cross section of the transparent laminate film of Comparative Example 1 was analyzed by SEM, it was found to have a three-layer structure with a 150 μm-thick resin layer and a 3 μm-thick resin layer laminated on top and bottom.

(Comparative Example 2)
A reflectance measurement test, a design evaluation test, a transmittance measurement test, a wearability evaluation test, a visibility evaluation test, a drop strength evaluation test, a scratch resistance evaluation test, an alcohol resistance evaluation test, a splash prevention functionality evaluation test, a UV transmittance measurement test, and an antifouling evaluation test were performed in the same manner as in Example 1, except that a commercially available low-reflection film (FG-10MR1, manufactured by Sharp Corporation) and a core layer on which a printed layer was formed were bonded to each other via a transparent adhesive layer (Panaclean series PD-S1, manufactured by Panac Corporation, thickness 25 μm).

The above results are shown in Tables 1 to 4. Table 1 shows the results of the reflectance measurement test and the design evaluation test. Table 2 shows the results of the transmittance measurement test. Table 3 shows the results of the wearability evaluation test, the visibility evaluation test, and the drop strength evaluation test. Table 4 shows the results of the scratch resistance evaluation test, the alcohol resistance evaluation test, and the splash prevention functionality evaluation test. Table 5 shows the results of the UV transmittance measurement test and the antifouling evaluation test.

In the design column of Table 1 above, "○" means that the areas of the transparent laminate film 30 of the face shield 10 where the printed layer 33 was not provided were not noticeable, and the printed layer 33 was noticeable. "△" means that depending on the angle at which the face shield is viewed and the surrounding lighting environment, the areas where the printed layer was not provided stood out, and the printed layer was not noticeable. Also, "×" means that the areas of the transparent laminate film of the face shield where the printed layer was not provided were noticeable, and the printed layer was not noticeable.

In the column for the wearability evaluation test in Table 3 above, "○" means that the wearer's reflection in the transparent laminate film 30 is not visible, and there is no impression that a face shield is being worn. "△" means that, depending on factors such as the surrounding lighting environment or the direction of the wearer's face, the wearer's reflection in the transparent laminate film is visible, but not always, and the wearer sometimes has the impression that a face shield is being worn, resulting in a slight feeling of fatigue. "×" means that the wearer's reflection in the transparent laminate film is visible, which interferes with work, and the wearer has the impression that a face shield is being worn, resulting in a feeling of fatigue.

In the visibility evaluation test column in Table 3 above, "○" means that the wearer's facial expression could be clearly seen. "△" means that depending on the angle at which the wearer is viewed, the observer is reflected in the transparent laminate film, making it difficult to see the wearer's facial expression. "×" means that regardless of the angle at which the wearer is viewed, the observer is reflected in the transparent laminate film, making it difficult to see the wearer's facial expression.

Furthermore, in the drop strength evaluation test column in Table 3 above, "○" means that no deformation or damage was found in the transparent laminate film of the face shield.

In the "Fingerprints" column of the scratch resistance evaluation test in Table 4 above, "○" means that the fingerprints could be wiped off without causing scratches on the transparent laminate film. Also, "×" means that scratches were caused on the transparent laminate film when the fingerprints were wiped off, and the transparent laminate film took on a cloudy white appearance due to the fine scratches.

In the "Pencil" column of the scratch resistance evaluation test in Table 4 above, "○" means that no scratches were made on the transparent laminate film. "△" means that light scratches were made on the transparent laminate film. Furthermore, "×" means that dark scratches were made on the transparent laminate film, deteriorating the appearance of the transparent laminate film.

In addition, in the alcohol resistance evaluation test column in Table 4 above, "○" means that there was no change in the appearance of the transparent laminate film. Also, "×" means that the transparent laminate film was discolored and its appearance was deteriorated.

In addition, in the column for the splash prevention functionality evaluation test in Table 4 above, "○" means that no colored ink was found to adhere to the paper. Also, "×" means that colored ink was found to adhere to the paper.

In the stain resistance evaluation test column in Table 5 above, "○" means that the lines disappeared after wiping. Also, "×" means that the oil-based ink could not be wiped off and the lines remained clearly.

As a result, as shown in Table 1, the transparent laminate film according to Comparative Example 1 had a visual reflectance Y value of 8.6%, and the transparent laminate film according to Comparative Example 2 had a visual reflectance Y value of 3.7%. In contrast, the transparent laminate film 30 according to Example 1 had a visual reflectance Y value of 0.6%, and the transparent laminate film 30 according to Example 2 had a visual reflectance Y value of 0.7%. In this way, the transparent laminate films 30 according to Examples 1 and 2 were able to reduce the visual reflectance Y value. This shows that the transparent laminate film 30 can make areas where the printing layer 33 is not provided less noticeable.

Also, as shown in Table 1, the transparent laminate film according to Comparative Example 1 had a reflectance of 8.6% for light with a wavelength of 550 nm, and the transparent laminate film according to Comparative Example 2 had a reflectance of 3.6% for light with a wavelength of 550 nm. In contrast, the transparent laminate film 30 according to Example 1 had a reflectance of 0.6% for light with a wavelength of 550 nm, and the transparent laminate film 30 according to Example 2 had a reflectance of 0.7% for light with a wavelength of 550 nm. In this way, the transparent laminate film 30 according to Examples 1 and 2 was able to reduce the reflectance of light with a wavelength of 550 nm. In addition, the transparent laminate film 30 according to Examples 1 and 2 had a reflectance of 0.8% and 0.7% for light with a wavelength of 450 nm, and a reflectance of 1.0% and 0.6% for light with a wavelength of 650 nm, respectively. In this way, the transparent laminate film 30 according to Examples 1 and 2 was able to reduce the reflectance of light in the cases where the wavelengths of light were 450 nm, 550 nm, and 650 nm. For this reason, it was found that the transparent laminate film 30 according to this embodiment can reduce the light reflectance.

As shown in Table 1, in the face shield according to Comparative Example 1, the areas where the printed layer was not provided were noticeable, and the printed layer was not noticeable. In addition, in the face shield according to Comparative Example 1, depending on the angle at which the face shield was viewed and the surrounding lighting environment, the areas where the printed layer was not provided were noticeable, and the printed layer was not easily noticeable. In contrast, in the face shields according to Examples 1 and 2, the areas where the printed layer 33 was not provided were not noticeable, and the printed layer 33 was able to stand out. In this way, it was found that the face shields 10 according to Examples 1 and 2 can display a design different from conventional designs, and can improve the design of the face shield.

Furthermore, as shown in Table 2, in the transparent laminate films of Comparative Example 1 and Comparative Example 2, when the light wavelength was 450 nm, the light transmittance was 87.7% and 93.7%, when the light wavelength was 550 nm, the light transmittance was 89.2% and 95.4%, and when the light wavelength was 650 nm, the light transmittance was 90.8% and 96.7%.
In contrast, in the transparent laminate film 30 according to Example 1 and Example 2, when the wavelength of light was 450 nm, the light transmittance was 94.7% and 96.4%, when the wavelength of light was 550 nm, the light transmittance was 97.3% and 98.3%, and when the wavelength of light was 650 nm, the light transmittance was 97.8% and 99.6%. Therefore, it was found that the transparent laminate film 30 according to the present embodiment can improve the light transmittance.

As shown in Table 3, in the wearability evaluation test, the transparent laminate film according to Comparative Example 1 showed a reflection of the wearer on the transparent laminate film, which hindered work and gave the impression that the wearer was wearing a face shield, resulting in a feeling of fatigue. In addition, the transparent laminate film according to Comparative Example 2 showed that the wearer's reflection on the transparent laminate film, etc., was visible, although not always, due to factors such as the surrounding lighting environment or the direction of the wearer's face, and sometimes gave the impression that the wearer was wearing a face shield, resulting in a weak but tired feeling. On the other hand, in Examples 1 and 2, the wearer's reflection on the transparent laminate film 30 was not visible, and the wearer did not have the impression that the face shield was being worn. In this way, the transparent laminate film 30 according to Examples 1 and 2 was able to reduce the reflection of the wearer on the transparent laminate film 30, and was able to suppress the wearer wearing the face shield 10 from feeling tired.

As shown in Table 3, in the visibility evaluation test, in the transparent laminate film of Comparative Example 1, the observer was reflected in the transparent laminate film, preventing confirmation of the wearer's facial expression regardless of the angle at which the wearer was viewed. In addition, in the transparent laminate film of Comparative Example 2, depending on the angle at which the wearer was viewed, the observer was reflected in the transparent laminate film, preventing confirmation of the wearer's facial expression. On the other hand, in the transparent laminate film 30 of Examples 1 and 2, the wearer's facial expression could be clearly confirmed.

Furthermore, as shown in Table 3, in the drop strength evaluation test, no deformation or scratches were found in the transparent laminate film 30 of the face shield 10 of Examples 1 and 2. In this way, it was found that the transparent laminate film etc. of the present embodiment can suppress a decrease in drop strength compared to conventional transparent laminate films.

Furthermore, as shown in Table 4, in the scratch resistance evaluation test, in the transparent laminate film 30 of Example 1, fingerprints could be wiped off without causing scratches on the transparent laminate film 30. In addition, in the transparent laminate film 30 of Example 1, when a pencil was rubbed against the transparent laminate film 30, no scratches were caused on the transparent laminate film 30. In this way, in the transparent laminate film 30 of Example 1, it was possible to suppress a decrease in the scratch resistance of the transparent laminate film 30.

In addition, as shown in Table 4, in the alcohol resistance evaluation test, the transparent laminate film 30 of Example 1 did not undergo any change in appearance. In this way, the transparent laminate film 30 of Example 1 was able to prevent the deterioration of the alcohol scratch resistance of the transparent laminate film 30.

Furthermore, as shown in Table 4, in the splash prevention functionality evaluation test, the face shields 10 according to Examples 1 and 2 were also able to prevent splashes of a certain size in front of the wearer H of the face shield 10.

Furthermore, as shown in Table 5, the transparent laminate film 30 according to Example 1 had a UV transmittance of 0.1%. In this way, the transparent laminate film 30 according to Example 1 was able to reduce the UV transmittance. This means that the wearer H can be made less susceptible to sunburn even when the wearer H is outdoors in an environment where he or she is exposed to direct sunlight.

Furthermore, as shown in Table 5, in the stain resistance evaluation test, the transparent laminate film 30 of Example 1 was able to wipe off the oil-based ink, and the lines disappeared after wiping. In this way, the transparent laminate film 30 of Example 1 was able to easily remove the oil-based ink that is difficult to remove. As a result, even if dirt adheres to the face shield 10, the dirt can be easily wiped off from the face shield 10, and the face shield 10 can be easily restored to a clean state.

The components disclosed in the above embodiments may be combined as needed. Alternatively, some components may be deleted from all the components shown in the above embodiments.

LIST OF SYMBOLS 10 Face shield 20 Holding member 21 Temple portion 22 Front portion 23 Pad portion 25 Band 27 Chin pad 28 Hook portion 30 Transparent laminated film 31a First transparent adhesive layer 31b Second transparent adhesive layer 32 Core layer 33 Printed layer 40 Front surface anti-reflection layer 41 Front surface anti-reflection functional layer 42 Front surface transparent substrate layer 43 Front surface refraction layer 44 Front surface hard coat layer 45 Front surface low refractive index layer 46 Front surface high refractive index layer 47 First front surface high refractive index layer 48 Second front surface high refractive index layer 50 Rear surface anti-reflection layer 51 Rear surface anti-reflection functional layer 52 Rear surface transparent substrate layer 53 Rear surface refraction layer 54 Rear surface hard coat layer 55 Rear surface low refractive index layer 56 Rear surface high refractive index layer 57 First rear surface high refractive index layer 58 Second rear surface high refractive index layer 60 Transparent laminated film with protective film 61: Surface protective film 62: Back protective film 301: Surface 302: Back C: Cheek E: Ear F: Face H: Wearer J: Chin M: Mouth N: Nose

Claims (30)

A transparent laminate film having a front surface and a back surface,
A core layer ;
a printing layer covering a part of the front surface or a part of the back surface of the core layer ;
a surface antireflection layer provided on one side of the core layer and constituting the surface;
a back surface antireflection layer provided on the other side of the core layer and constituting the back surface ;
In the region where the printing layer is not provided, the luminous reflectance Y value is 0.0% or more and 2.0% or less,
the printing layer is provided between the core layer and the front-surface antireflection layer or between the core layer and the rear-surface antireflection layer,
the front-surface antireflection layer includes a front-surface antireflection functional layer and a front-surface transparent substrate layer disposed in this order from the front surface to the back surface,
The back surface antireflection layer is a transparent laminate film having a back surface antireflection functional layer and a back surface transparent substrate layer arranged in this order from the back surface to the front surface . The transparent laminate film according to claim 1, in which the reflectance of light having a wavelength of 550 nm is 2% or less and the total light transmittance is 90% or more in the area where the printed layer is not provided. The transparent laminate film according to claim 1 or 2, in which the transmittance of ultraviolet light having a wavelength of 380 nm or less in the area where the printed layer is not provided is 1% or less. The transparent laminate film according to any one of claims 1 to 3, wherein the core layer contains polyethylene terephthalate. a first transparent adhesive layer that adheres the front-surface antireflection layer and the core layer;
The transparent laminate film according to claim 1 , further comprising a second transparent adhesive layer that bonds the core layer and the back surface antireflection layer. The transparent laminate film according to claim 5 , wherein the first transparent adhesive layer and the second transparent adhesive layer each contain an acrylic adhesive. A surface antireflection layer constituting the surface;
A back surface antireflection layer constituting a back surface;
a printed layer provided between the front-surface antireflection layer and the back-surface antireflection layer and covering a part of the front-surface antireflection layer,
In the region where the printing layer is not provided, the luminous reflectance Y value is 0.0% or more and 2.0% or less,
the front-surface antireflection layer includes a front-surface antireflection functional layer and a front-surface transparent substrate layer disposed in this order from the front surface to the back surface,
The back surface antireflection layer is a transparent laminate film having a back surface antireflection functional layer and a back surface transparent substrate layer arranged in this order from the back surface to the front surface . 8. The transparent laminate film according to claim 7 , wherein in an area where the printed layer is not provided, the reflectance of light having a wavelength of 550 nm is 2% or less, and the total light transmittance is 90% or more. 9. The transparent laminate film according to claim 7 , wherein the transmittance of ultraviolet light having a wavelength of 380 nm or less in an area where the printed layer is not provided is 1% or less . the front-surface antireflection functional layer is a coating layer coated on the front-surface transparent substrate layer,
The transparent laminate film according to claim 1 , wherein the rear surface antireflection functional layer is a coating layer coated on the rear surface transparent substrate layer. The transparent laminate film according to claim 1 , wherein the front-surface antireflection functional layer and the back-surface antireflection functional layer are each made of a cured product of an ionizing radiation curable resin composition. The transparent laminate film according to claim 11 , wherein the ionizing radiation curable resin composition contains a (meth)acrylate compound. The front-surface antireflection functional layer includes a front-surface refraction layer and a front-surface hard coat layer arranged in this order from the front surface to the back surface,
The transparent laminate film according to claim 1 , wherein the back surface antireflection functional layer includes a back surface refraction layer and a back surface hard coat layer arranged in this order from the back surface to the front surface. the surface hard coat layer is a coating layer coated on the surface transparent substrate layer,
the surface refractive layer is a coating layer coated on the surface hard coat layer,
the back surface hard coat layer is a coating layer coated on the back surface transparent substrate layer,
The transparent laminate film according to claim 13 , wherein the rear surface refraction layer is a coating layer coated on the rear surface hard coat layer. the surface refractive layer includes a surface low refractive index layer and a surface high refractive index layer arranged in this order from the surface to the back surface,
The transparent laminate film according to claim 13 or 14 , wherein the back surface refractive layer includes a back surface low refractive index layer and a back surface high refractive index layer arranged in this order from the back surface to the front surface. the surface high refractive index layer includes a first surface high refractive index layer and a second surface high refractive index layer arranged in this order from the surface to the back surface,
The transparent laminate film according to claim 15 , wherein the back surface high refractive index layer includes a first back surface high refractive index layer and a second back surface high refractive index layer arranged in this order from the back surface to the front surface. the refractive index of the first surface high refractive index layer is higher than the refractive index of the second surface high refractive index layer;
The transparent laminate film according to claim 16 , wherein the refractive index of the first back surface high refractive index layer is higher than the refractive index of the second back surface high refractive index layer. The transparent laminate film according to claim 17 , wherein the front transparent substrate layer and the back transparent substrate layer contain triacetyl cellulose or polyethylene terephthalate. The transparent laminate film according to claim 17 , wherein one of the front transparent substrate layer and the back transparent substrate layer contains triacetyl cellulose, and the other contains polyester. The transparent laminate film according to claim 17 , wherein the front transparent substrate layer and the back transparent substrate layer each contain polyester. The transparent laminate film according to any one of claims 1 to 20 , having a thickness of 40 µm or more and 500 µm or less. The transparent laminate film according to any one of claims 1 to 21 , which has a restoring function. The transparent laminate film according to any one of claims 1 to 22 , which is used for a face shield for protecting the face of a wearer. A transparent laminate film according to any one of claims 1 to 23 ,
a surface protection film for protecting the surface of the transparent laminate film;
A transparent laminate film with a protective film, comprising a back surface protective film that protects the back surface of the transparent laminate film. In a face shield that protects the wearer's face,
A holding member attached to the wearer;
A face shield comprising: a transparent laminate film according to any one of claims 1 to 24 attached to the retaining member and covering at least a portion of the face of the wearer. The face shield according to claim 25 , wherein the printed layer is positioned to overlap the cheek of the wearer when viewed from the front. 27. The face shield according to claim 25 , wherein when the wearer wears the face shield, a distance between the wearer's nose and the holding member is 100 mm or less. 28. The face shield according to any one of claims 25 to 27, wherein the retaining member has a pair of temple portions that abut against the wearer's ears, a front portion that connects the pair of temple portions to each other, and a pair of pad portions that extend downward from the front portion and abut against the wearer's nose. 28. A face shield as claimed in any one of claims 25 to 27 , wherein the retaining member comprises a band that circumferentially wraps around the wearer's head. 28. The face shield according to claim 25, wherein the retaining member has a chin pad that abuts against the chin of the wearer and a pair of hook portions that are connected to the chin pad and hooked onto the wearer's ears , and the transparent laminate film covers at least the wearer's mouth.