JP6515407B2 - Window film and method of manufacturing window film - Google Patents

Description

  The present invention relates to a window film and a method of manufacturing a window film.

  Window film is an adhesive film that is applied to window glass of automobiles, buildings, etc. for the purpose of UV cut in sunlight, protection of privacy, crime prevention, prevention of scattering of glass, decoration, etc. There is.

  As such a window film, what equips the surface of a base material with a hard-coat layer in order to improve the abrasion resistance of a film and the ease of handling is known.

  For example, a shatterproof film is disclosed in which a pressure-sensitive adhesive layer, a substrate, and a hard coat layer are laminated in this order (see, for example, Patent Document 1).

JP, 2009-255351, A

A film having a hard coat property is wound in a roll and stored after being coated with a hard coat layer from the viewpoint of productivity and handleability. However, when a film having a hard coat layer is wound in a roll, there is a problem that the hard coat layer and another layer adjacent to the hard coat layer stick and it can not be wound up well. . The other layer adjacent to the hard coat layer is, for example, a release sheet laminated on the pressure-sensitive adhesive layer of the window film. In addition, in the process of manufacturing a window film, a film in the form of a hard coat film, in which a hard coat layer is formed on a substrate film, may be wound in a roll. In this case, the other layer adjacent to the hard coat layer is a base film.
The anti-scattering film disclosed in Patent Document 1 also has room for improvement on the prevention of sticking between the hard coat layer and another layer adjacent to the hard coat layer.

Then, as a result of the present inventors earnestly examining the above-mentioned problem, in a window film provided with a hard court layer on one side of a substrate film and having an adhesive layer on the other side of the substrate film, It was found that a window film in which the sticking of the hard coat layer is effectively prevented can be obtained by blending the hydrophobized silica sol with the hard coat layer forming material forming the hard coat layer, and the present invention was completed. It is a thing.
That is, according to the present invention, for example, even when a film having a hard coat layer is wound in a roll, a window film in which sticking of the hard coat layer is effectively prevented, and sticking of the hard coat layer It is an object of the present invention to provide a method of manufacturing a window film in which sticking is effectively prevented.

The present invention is as follows.
[1] A hard coat layer is laminated on one side of a substrate film,
It is a window film provided with an adhesive layer containing a UV absorber on the other side of the substrate film,
The hard coat layer comprises a cured product of a hard coat layer-forming material containing at least (A) an energy ray-curable resin and (B) a hydrophobized silica sol,
The compounding amount of the (B) hydrophobized silica sol is in the range of 0.1 to 25 parts by weight in terms of solid content with respect to 100 parts by weight of the (A) energy ray-curable resin,
A window film characterized in that (B) the hydrophobized silica sol is unevenly distributed on the surface side of the hard coat layer after curing the hard coat layer-forming material opposite to the base film.
[2] The window film according to [1], wherein the hard coat layer-forming material further contains (C) a leveling agent.
[3] The (C) leveling agent comprises silicone, silicone-modified acrylic, polyether-modified polydimethylsiloxane, polyetherester-modified hydroxyl group-containing polydimethylsiloxane, polyester-modified hydroxyl group-containing polydimethylsiloxane, polyether-modified polydimethylsiloxane The window film according to the above [2], which is at least one selected from the group consisting of
[4] The compounding amount of the (C) leveling agent is a value within the range of 0.045 to 5 parts by weight in terms of solid content with respect to 100 parts by weight of the (A) energy ray-curable resin The window film according to the above [2] or [3].
[5] The window film according to any one of [1] to [4], wherein the average particle diameter of the (B) hydrophobized silica sol is a value within the range of 10 to 100 nm.
[6] The contact angle of water measured according to JIS R 3257 with respect to the coating film when the (B) hydrophobized silica sol is a coating film is a value of 100 ° or more [1] Window film as described in any one of-[5].
[ 7 ] The transmittance of ultraviolet light having a wavelength of 300 to 380 nm measured according to JIS A 5759 of the window film is less than 3%, any one of the above [1] to [ 6 ] Window film described in
[ 8 ] The window film according to any one of claims 1 to 7 , wherein a haze measured according to JIS K 7136: 2000 of the window film is 1.0% or less.
[ 9 ] The arithmetic average roughness Ra measured in accordance with JIS B 0601-1994 on the surface of the hard coat layer is a value within the range of 1.5 to 5 nm [1] The window film according to any one of [ 8 ] to [ 8 ].
[ 10 ] Any one of the above [1] to [ 9 ] is characterized in that the dynamic friction force between the hard coat layer and the base film measured according to JIS K 7125 is 15 N or less. Window film described in
[ 11 ] A method for producing a window film, wherein a hard coat layer is laminated on one side of a substrate film, and an adhesive layer is provided on the other side of the substrate film,
The manufacturing method of the window film characterized by including following process (1)-(3).
(1) A step of forming a hard coat layer forming material containing at least (A) energy ray curable resin and (B) hydrophobized silica sol on one side of the base film (2) forming the hard coat layer material is cured, the (B) hydrophobic silica sol, of the hard coat layer-forming material wherein the hard coat layer after curing, and wherein the substrate film is unevenly distributed on the opposite surface of the ( B) A step of forming a hard coat layer in which the amount of the hydrophobized silica sol is in the range of 0.1 to 25 parts by weight in terms of solid content with respect to 100 parts by weight of the (A) energy ray-curable resin (3) A step of forming a pressure-sensitive adhesive layer containing a UV absorber on the other side of the base film

According to the present invention, it is possible to provide a window film in which sticking of the hard coat layer is effectively prevented.
According to the present invention, it is possible to provide a method of manufacturing a window film in which sticking of the hard coat layer is effectively prevented.

It is the figure which demonstrated typically the window film which concerns on one Embodiment of this invention. It is the figure which demonstrated typically the window film which concerns on one Embodiment of this invention. It is a figure for demonstrating the hard-coat layer in which the surface contains a hydrophilic silica sol.

<< Window Film >>
First Embodiment
In one embodiment, the present invention is a window film having a hard coat layer laminated on one side of a substrate film and a pressure-sensitive adhesive layer containing a UV absorber on the other side of the substrate film. The hard coat layer is made of a cured product of a hard coat layer forming material containing at least (A) an energy ray curable resin and (B) a hydrophobized silica sol, and the (B) hydrophobized silica sol is the hard disc The present invention provides a window film characterized in that the hard coat layer after curing the coat layer forming material is unevenly distributed on the surface side opposite to the base film.
Hereinafter, the window film of the present embodiment will be described in detail with reference to the drawings as appropriate.

FIG. 1 is a cross-sectional view schematically showing an embodiment of a window film according to the present invention. However, the window film according to the present invention is not limited to those shown here.
In the window film 1 shown here, the hard coat layer 12 is laminated on one side of the base film 10, and the pressure-sensitive adhesive layer 14 is laminated on the other side of the base film 10. The hard coat layer 12 is laminated on the surface 10 a of the substrate film 10, and the pressure-sensitive adhesive layer 14 is laminated on the surface 10 b of the substrate film 10. The hydrophobized silica sol 16 is unevenly distributed on the surface side of the hard coat layer 12 opposite to the side on which the base film 10 is laminated. A release sheet 18 is laminated on the surface 14 b of the pressure-sensitive adhesive layer 14.
Hereinafter, the window film of the present embodiment will be specifically described.

1. Hard coat layer forming material (1) (A) energy ray curable resin (1) -1. Type The hard coat layer-forming material (A) The type of energy ray-curable resin is not particularly limited, can be selected from conventionally known ones, and energy ray-curable monomers, oligomers or compositions containing them Etc.
Examples of energy ray curable monomers include polyfunctional (meth) acrylates, and examples of energy ray curable oligomers include urethane (meth) acrylates, polyester (meth) acrylates, polyether (meth) acrylates, silicone (meth) acrylates, etc. Be
As polyfunctional (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, ethylene glycol di (meth) acrylate, Propylene glycol di (meth) acrylate, hexanediol di (meth) acrylate, trimethylolethane tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, and pentaerythritol tetra (meth) acrylate Etc., pentapentaerythritol multifunctional (meth) acrylate, dipentaerythritol penta (meth) acrylate, and dipentaerythritol such as dipentaerythritol hexa (meth) acrylate Functional (meth) acrylate, glycerol tri (meth) acrylate, triallyl (meth) acrylate.
Among these, pentaerythritol multifunctional (meth) acrylate or dipentaerythritol multifunctional (meth) acrylate is more preferable because it can impart appropriate hardness to the hard coat layer.

It is also preferable that the polyfunctional (meth) acrylate contains a polyfunctional (meth) acrylate of an EO (ethylene oxide) or PO (propylene oxide) addition type.
EO (ethylene oxide) or PO (propylene oxide) addition type polyfunctional (meth) acrylate is a compound obtained by esterification of an EO or PO addition type polyhydric alcohol with acrylic acid, and more specifically And EO or PO modified glycerol triacrylate, EO or PO modified trimethylolpropane acrylate, EO or PO modified pentaerythritol tetraacrylate, EO or PO modified dipentaerythritol hexaacrylate and the like.
Among them, EO or PO modified dipentaerythritol hexaacrylate, or EO or PO modified trimethylolpropane tetraacrylate because it is possible to prevent cracks and cracks in the hard coat layer by giving the hard coat layer appropriate flexibility. Is more preferred.

  In addition, in the EO or PO addition type polyfunctional (meth) acrylate, in order to impart appropriate flexibility to the hard coat layer, 6 to 18 moles of EO or PO added per 1 mol of such polyfunctional (meth) acrylate are The value is preferably in the range, and more preferably 8 to 16 moles.

(1) -2. In addition, the (A) energy ray-curable resin constituting the hard coat layer forming material is (a1) a polyfunctional (meth) acrylate compound, and (a2) an ethylene oxide or propylene oxide addition type polyfunctional (meth) The weight ratio of the acrylate compound to the (a1) polyfunctional (meth) acrylate compound and (a2) ethylene oxide or propylene oxide addition type polyfunctional (meth) acrylate compound is 100: 0 to 20 It is preferable that the value is in the range of 80:80.
The reason for this is that the hard coat layer-forming material is a polyfunctional (meth) acrylate compound which has a relatively high hardness by energy ray irradiation, and an ethylene oxide or propylene oxide addition type having a relatively high flexibility even by the energy ray irradiation. It is because the hardness of a hard-coat layer can be easily adjusted by containing the polyfunctional compound of the above at a predetermined content.
That is, when the content weight ratio of the (a1) polyfunctional (meth) acrylate compound is less than 20, the abrasion resistance of the hard coat layer after curing may be reduced.
Therefore, the content weight ratio of (a1) polyfunctional (meth) acrylate compound to (a2) ethylene oxide or propylene oxide addition type polyfunctional (meth) acrylate compound is within the range of 95: 5 to 30:70. It is more preferable that it is, and it is further more preferable that it is a value within the range of 90:10 to 50:50.

(1) -3. (D) Photoinitiator In the hard coat layer-forming material of the present invention, when ultraviolet rays are used as energy rays, it is preferable to contain (D) a photopolymerization initiator.
The reason for this is that the hard coat layer can be efficiently formed when the hard coat layer forming material is irradiated with ultraviolet light by containing a photopolymerization initiator.
Here, the photopolymerization initiator refers to a compound that generates radical species by irradiation of active energy rays such as ultraviolet rays.
As the photopolymerization initiator, for example, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2-hydroxy-1- {4- [4- (2-hydroxy-2-methylpropionyl) Benzyl] phenyl} -2-methylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropanone-1-one, 4- (2 -Hydroxye X) phenyl-2- (hydroxy-2-propyl) ketone, benzophenone, p-phenyl benzophenone, 4, 4-diethylamino benzophenone, dichloro benzophenone, 2-methyl anthraquinone, 2-ethyl anthraquinone, 2-tertiary butyl anthraquinone, 2 -Aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyl dimethyl ketal, acetophenone dimethyl ketal, p-dimethylamine benzoate, oligo [2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl] propan-1-one], etc. may be mentioned, and one of these may be used alone, or two or more It may be used in combination.
In addition, as content in the case of containing (D) a photoinitiator, it is preferable to set it as the value within the range of 0.2-20 weight part with respect to 100 weight part of (A) energy ray curable resin. The value is more preferably in the range of 0.5 to 15 parts by weight, and still more preferably in the range of 1 to 13 parts by weight.

(2) (B) Hydrophobized silica sol (2) -1. Type The hard coat layer-forming material further comprises (B) a hydrophobized silica sol.
Here, as a kind of silica sol, a sol of silica fine particles using an alkoxysilane compound, a chlorosilane compound or the like as a raw material can be mentioned.
The alkoxysilane compound is not particularly limited as long as it is a silicon compound having a hydrolyzable alkoxyl group, and for example, a compound represented by General Formula (1) can be mentioned.
R ¹ _n Si (OR ² ) _4-n (1)
(Wherein R ¹ is a hydrogen atom or a nonhydrolyzable group, specifically an alkyl group, a substituted alkyl group (substituent: halogen atom, epoxy group, (meth) acryloyloxy group etc.), an alkenyl group, R ² represents an aryl group or an aralkyl group, and R ² represents a lower alkyl group, n is an integer of 0 to 2, and when R ¹ and OR ² are each plural, plural R ¹ may be the same or different And two or more OR ² may be the same or different.)

  Further, as the alkoxysilane compound represented by the general formula (1), tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, tetraisopropoxysilane, tetra-n-butoxysilane, tetraisobutoxysilane, tetra -Sec-butoxysilane, tetra-tert-butoxysilane, trimethoxysilane hydride, triethoxysilane hydride, tripropoxysilane hydride, methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltriisopropoxysilane, ethyl Trimethoxysilane, Ethyltriethoxysilane, Propyltriethoxysilane, Butyltrimethoxysilane, Phenyltrimethoxysilane, Phenyltriethoxysilane, γ-Acryloyloxypeptides Pilltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, dimethyldimethoxysilane, methylphenyldimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, divinyldimethoxysilane, divinyldiethoxysilane, etc. One or more kinds thereof Combinations are preferred.

In this case, an inorganic silica-based cured product can be obtained by completely hydrolyzing a compound wherein n is 0 or n is 1 to 2 and R ¹ is a hydrogen atom as an alkoxysilane compound, and partial hydrolysis leads to a polyorgano. A siloxane-based cured product or a mixed system cured product of an inorganic silica-based and a polyorganosiloxane-based can be obtained.
On the other hand, in a compound in which n is 1 to 2 and R ¹ is a nonhydrolyzable group, a polyorganosiloxane-based cured product is obtained by partial or complete hydrolysis since it has a nonhydrolyzable group.
Examples of chlorosilane compounds include ethyldichlorosilane, ethyltrichlorosilane, dimethyldichlorosilane, trichlorosilane, trimethylchlorosilane, dimethyldichlorosilane, methyltrichlorosilane and the like.

The silica sol is a dispersion of silica fine particles in water or an organic solvent in a sol state.
Such organic solvents are not particularly limited, and methanol, ethanol, isopropanol, ethylene glycol, n-propyl cellosolve, methyl ethyl ketone, methyl isobutyl ketone, dimethyl acetamide, propylene glycol monomethyl ether, cyclohexane, benzene, toluene and the like can be used relatively. Particularly preferred are methyl isobutyl ketone having a high boiling point and propylene glycol monomethyl ether.

In addition, the silica sol according to the present invention is characterized in that it is a hydrophobized silica sol in which a part or all of silanol groups on the surface of a silica particle is treated with a surface modifier having a hydrophobic group.
Here, as a surface modifier, the silane coupling agent which has a functional group which can react with respect to the silanol group on the surface of a silica particle, and a hydrophobic group is mentioned.
More specifically, as a hydrophobized silica sol, for example, SIRPGM15WT% -E26 manufactured by CIK Nanotech Inc. may be mentioned.

(2) -2. Degree of Hydrophobicity The degree of hydrophobicity of the silica sol was determined by coating the silica sol on a PET film, removing the solvent to prepare a silica sol coating film, and measuring the contact angle of water to the coating film. The measurement method of the contact angle of water with respect to the coating film of silica sol can be calculated by preparing a silica sol coating film as specifically described in Example 1, and measuring the contact angle of water.
More specifically, it is preferable to set the contact angle of water to the coating film when the silica sol is a coating film to a value of 100 ° or more.
That is, if the contact angle of water measured according to JIS R 3257 to the coating of silica sol is a value of 100 ° or more, it can be judged that the surface of silica sol is hydrophobic.
By configuring in this manner, sticking and blocking of the hard coat layer can be effectively prevented.
Here, referring to FIG. 1, more specifically, when the hard coat layer-forming material is applied to the surface of a substrate and cured, the hydrophobized silica sol 16 of the present invention is otherwise It is believed that the phase separation with the components occurs, and the distribution is largely localized on the surface side opposite to the substrate surface 10, and the proportion near the substrate surface and in the hard coat layer is low.
Therefore, the addition of a small amount of hydrophobized silica sol can impart an appropriate surface roughness to the surface of the hard coat layer, so that the hard coat is obtained even when the film having the hard coat layer is rolled up. Layer sticking can be effectively prevented. In addition, even when films having a hard coat layer overlap and time passes, it is possible to prevent blocking (pressure bonding) of the films from occurring.
That is, it can be understood that a window film with high transparency can be obtained because the effects of predetermined adhesion resistance and blocking resistance (sometimes referred to as antiblocking) can be exhibited with a relatively small amount of addition. Be done.
When the contact angle of water with respect to the coating of the hydrophobized silica sol becomes excessively high, the adhesion may be reduced when forming the adhesive layer or the printing layer on the hard coat layer, and therefore the coating of the hydrophobized silica sol It is more preferable to set the contact angle of water to the membrane to a value within the range of 100 to 130 °.
On the other hand, when the contact angle of water to the coating of the silica sol becomes a value less than 100 ° and the hydrophilicity becomes high, as shown in FIG. 3, the silica sol 19 is not unevenly distributed only on the surface side opposite to the base film. It has been confirmed that the hard coat layer is dispersed in the whole.
Therefore, it is understood that a relatively large amount of silica sol needs to be blended in order to impart a predetermined surface roughness to the hard coat layer.

(2) -3. Average Particle Size The average particle size of the hydrophobized silica sol according to the present invention is preferably 10 to 100 nm.
By this configuration, the transparency of the window film can be maintained or effectively improved.
When the average particle diameter of the hydrophobized silica sol is less than 10 nm, it becomes difficult to obtain a predetermined surface roughness, and in particular, with a small amount of formulation, it is difficult to prevent the occurrence of sticking and blocking of the hard coat layer. It may be
On the other hand, when the average particle diameter of the hydrophobized silica sol exceeds 100 nm, the optical properties of the window film may be excessively lowered.
Therefore, the average particle diameter of the hydrophobized silica sol is more preferably in the range of 10 to 50 nm, and still more preferably in the range of 15 to 40 nm.
The average particle size of the silica sol is the particle size (median diameter D50) at an integrated value of 50% in the volume-based particle size distribution determined using a laser diffraction confusion type particle size distribution analyzer, and means the average primary particle size. Do.

(2) -4. Compounding Amount Further, the compounding amount of the hydrophobized silica sol is preferably a value in the range of 0.3 to 55 parts by weight in terms of solid content with respect to 100 parts by weight of the (A) energy ray-curable resin.
By such a configuration, despite the addition of a relatively small amount, the hard coat layer can be effectively localized on the surface side, and the transparency of the window film can be effectively improved.
When the amount of the hydrophobized silica sol is less than 0.3 parts by weight, it may be difficult to exhibit the effect of preventing sticking and blocking of the hard coat layer.
On the other hand, when the content of the hydrophobized silica sol exceeds 55 parts by weight, the adhesion and scratch resistance of the film may be excessively reduced.
Further, as described above, the hydrophobized silica sol tends to be unevenly distributed on the surface side opposite to the substrate surface in the hard coat layer, so the compounding amount of hydrophobized silica sol is (A) 100 parts by weight of the energy ray curable resin. On the other hand, when it is in the range of 0.3 to 25 parts by weight in terms of solid content, even if the blending amount of the hydrophobized silica sol is relatively small, the sticking resistance effect and the blocking resistance effect are effectively developed. In addition to transparency, the film can be suitably used as a window film for which transparency is required.
Accordingly, the compounding amount of the hydrophobized silica sol is more preferably a value within the range of 0.1 to 25 parts by weight in terms of solid content with respect to 100 parts by weight of the (A) energy ray curable resin. A value within the range of 15 parts by weight is more preferable, a value within the range of 0.1 to 7.0 parts by weight is particularly preferable, and a value within the range of 0.1 to 4.0 parts by weight Is particularly preferred.

(2) -5. Distribution The (B) hydrophobized silica sol according to the present invention is unevenly distributed on the surface side of the hard coat layer after curing the hard coat layer-forming material opposite to the base film. The state of uneven distribution of the hydrophobized silica sol can be confirmed by photographing the cross section of the hard coat layer with a scanning electron microscope (SEM) or the like.
The “hydrophobicized silica sol is“ localized on the surface side of the hard coat layer after curing the hard coat layer-forming material on the surface opposite to the base film ”” means that the hydrophobized silica sol in the hard coat layer is The distribution is not uniform, and the distribution of the hydrophobized silica sol on the surface side (surface layer portion) opposite to the base film in the hard coat layer is hydrophobic on at least the inner side (middle layer portion etc.) of the hard coat layer than the surface layer. It is a state in which the distribution of the oxidized silica sol is enhanced.

  The presence of the hydrophobized silica sol corresponds to the total amount (100 atom%) of carbon atoms, oxygen atoms, and silicon atoms measured by XPS analysis in the depth direction in the region from the outermost surface of the window film to the position of 5 nm. It can confirm by measuring a silicon atom concentration. This is effective when it is understood that silicon atoms measured by XPS analysis in the depth direction reflect the abundance ratio of silica sol in the region from the outermost surface of the hard coat layer to the position of 5 nm, for example, As in the window film of the present embodiment, the hard coat layer-forming material does not contain a silicon atom-containing leveling agent. In such a case, in the region from the outermost surface of the hard coat layer to the position of 5 nm, silicon is used with respect to the total amount (100 atom%) of carbon atoms, oxygen atoms, and silicon atoms measured by XPS analysis in the depth direction. The atomic concentration is preferably in the range of 0.5 to 5.0 atom%, more preferably in the range of 1.0 to 4.5 atom%, and in the range of 3.0 to 4.2 atom%. More preferably, the value is By setting the silicon atom concentration to the above value, a window film excellent in sticking resistance can be obtained.

(3) Other Additives In addition, other additives can be included as appropriate as long as the effects of the present invention are not impaired.
Examples of other additives include antioxidants, ultraviolet light absorbers, antistatic agents, polymerization accelerators, polymerization inhibitors, infrared light absorbers, plasticizers, and dilution solvents.
In addition, it is preferable to generally make content of an other additive into the value within the range of 0.01-5 weight part with respect to 100 weight part of (A) energy ray cured resin, and 0.02-3 weight It is more preferable to set the value within the range of part, and it is further preferable to set the value within the range of 0.05 to 2 parts by weight.

(4) Thickness Moreover, it is preferable to make thickness of the hard-coat layer 12 illustrated in FIG. 1 into the value within the range of 0.5-10 micrometers.
The reason is that when the thickness of the hard coat layer is less than 0.5 μm, the abrasion resistance may be significantly reduced.
On the other hand, when the thickness of the hard coat layer exceeds 10 μm, the curl may be increased.
Accordingly, the thickness of the hard coat layer is more preferably in the range of 0.5 to 5 μm, and still more preferably in the range of 1.0 to 4 μm.

2. Base Film (1) Type As the resin used for the base film 10 illustrated in FIGS. 1 (a) to 1 (b), those having excellent flexibility and transparency are preferable, and polyethylene terephthalate and polybutylene terephthalate are preferable. , Polyester films such as polyethylene naphthalate, polycarbonate film, polyethylene film, polypropylene film, cellophane, diacetyl cellulose film, triacetyl cellulose film, acetyl cellulose butyrate film, polyvinyl chloride film, polyvinylidene chloride film, polyvinyl alcohol film, ethylene -Vinyl acetate copolymer film, polystyrene film, polymethyl pentene film, polysulfone film, polyetheretherketone film, polyether Le sulfone film, polyether imide film, a polyimide film, a fluororesin film, a polyamide film, an acrylic resin film, polyurethane resin film, norbornene resin film, other plastic films such as cycloolefin resin film.
Among these, it is preferable to use a transparent resin film made of polyethylene terephthalate or polycarbonate because of its excellent transparency and versatility.

(2) Thickness Moreover, it is preferable to make thickness of the base film 10 illustrated in FIG. 1 into the value within the range of 15-250 micrometers.
The reason for this is that when the thickness of the substrate film is less than 15 μm, the handleability is significantly reduced, for example, wrinkles easily occur. On the other hand, when the thickness of the substrate film exceeds 250 μm, the handleability is increased. In particular, it may be difficult to make it roll-shaped.
Therefore, it is more preferable to set the thickness of the base film to a value within the range of 25 to 125 μm, because the balance between the mechanical strength and the light transmittance is better.

(3) Primer layer Although not shown, by providing a primer layer on the surface of the base film, the adhesion between the base film and the hard coat layer is improved to further improve the scratch resistance of the hard coat layer. be able to.
Here, as a constituent material of a primer layer, urethane resin, an acrylic resin, an epoxy resin, polyester resin, a silicone resin etc. 1 type individually or in combination of 2 or more types is mentioned.

Moreover, it is preferable to make thickness of a primer layer into the value within the range of 0.01-20 micrometers.
The reason for this is that when the thickness of the primer layer is less than 0.01 μm, the primer effect may not be exhibited. On the other hand, when the thickness of the primer layer exceeds 20 μm, the light transmittance may be reduced when the window film is formed.
Therefore, it is more preferable to set the thickness of the primer layer to a value within the range of 0.1 to 15 μm, because the balance between the primer effect and the light transmittance is better.

3. Properties of Hard Coat Layer (1) Surface Roughness of Hard Coat Layer In addition, the arithmetic average roughness (Ra) measured in accordance with JIS B 0601-1994 on the surface of the hard coat layer 12 illustrated in FIG. 1 Is preferably in the range of 1.5 to 5 nm.
By this configuration, fine unevenness can be obtained on the surface of the obtained hard coat layer, and sticking and blocking of the hard coat layer can be suitably prevented.
When the arithmetic average roughness (Ra) is less than 1.5 nm, the hard coat layer may stick to another layer adjacent to the hard coat layer when the film having the hard coat layer is wound up or stacked. May be difficult to prevent.
On the other hand, when the arithmetic mean roughness (Ra) becomes a value exceeding 5 nm, the light transmittance may be significantly reduced.
Therefore, the arithmetic average roughness (Ra) on the surface of the hard coat layer is more preferably in the range of 2.0 to 4 nm, and is preferably in the range of 2.5 to 3.5 nm. More preferable.

(2) Dynamic Friction Force of Hard Coat Layer Further, the dynamic friction force between the hard coat layer and the base film to be measured according to JIS K 7125 is preferably 15 N or less, and 12 N or less. Is more preferable, and 7 N or less is more preferable. The reason for this is to prevent the hard coat layer from sticking to the adjacent layer when the film having the hard coat layer is wound up or stacked when the dynamic friction force has a value exceeding 15 N. May be difficult.

  When the dynamic friction force is measured as described in Example 1, which will be described later, in accordance with JIS K 7125, the dynamic friction force does not occur between the hard coat layer and the base film under the condition that zipping does not occur. It is preferable to use a measurement value of

  Here, “zipping” is a phenomenon also referred to as “stick slip”, and is considered to be a phenomenon that occurs when the value of kinetic friction between films is too high when kinetic friction is measured. In the state of the zipping, for example, even if a force is applied to cause the film A to slide on the film B, the films A and B stick and hardly slip, and the value of the kinetic friction measured accordingly increases. After that, when the film A is continuously applied to slide on the film B, the adhesion between the film A and the film B is released and slips out, and the value of the dynamic friction force measured is reduced at a stretch. . When the measurement is continued, the sliding of the film A on the film B repeats stopping and advancing, and the value of the dynamic friction force measured also repeats rising and falling. When the dynamic friction force is measured, if it does not show a constant value and the value fluctuates up and down, it can be considered that zipping has occurred (the number of waveforms at this time should be 10 or more) preferable.).

  Since the zipping means that the value of the dynamic friction force between the films is high, the combination of the hard coat layer and the base film is described in Example 1 described later according to JIS K 7125. When dynamic friction force is measured like this, it is preferable to set it as the combination which does not produce a zipping. With such a configuration, it is possible to make a window film in which sticking of the hard coat layer is more effectively prevented.

4. Pressure-Sensitive Adhesive Layer The pressure-sensitive adhesive layer-forming material is composed of, for example, a pressure-sensitive adhesive and a UV absorber.
The thickness of the pressure-sensitive adhesive layer 14 illustrated in FIG. 1 is, for example, 5 to 100 μm, and for example, 10 to 60 μm.

(1) Pressure-sensitive adhesive In the window film of the present embodiment, a pressure-sensitive adhesive layer for sticking to an adherend such as window glass is formed on the surface of the base film on which the hard coat layer is not formed. be able to. The pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer is preferably a window film pressure-sensitive adhesive suitable for window film applications, and, for example, an acrylic pressure-sensitive adhesive, a urethane-based pressure-sensitive adhesive and a silicone pressure-sensitive adhesive are preferably used.

(2) UV Absorber In the window film of the present embodiment, the pressure-sensitive adhesive layer contains a UV absorber.
As a UV absorber, for example, 2- (2′-hydroxy-3 ′, 5′-di-tert-butylphenyl) -5-chlorobenzotriazole, 2- (2′-hydroxy-3′-tert-butyl -5'-Methylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-3'-tert-amyl-5'-isobutylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-) 2'-hydroxyphenyl such as 3'-isobutyl-5'-methylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-3'-isobutyl-5'-propylphenyl) -5-chlorobenzotriazole 2- (2′-hydroxy-3 ′, 5′-di-tert-butylphenyl) benzotriazole, 2-chlorobenzotriazole ultraviolet absorber; 2- (2'-hydroxy-5'-methylphenyl) benzotriazole, etc. 2'-hydroxyphenylbenzotriazole-based ultraviolet light absorbers; 2,2'-dihydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4,4 2,2'-dihydroxybenzophenone-based ultraviolet absorbers such as '-dimethoxybenzophenone and 2,2', 4,4'-tetrahydroxybenzophenone; 2 such as 2-hydroxy-4-methoxybenzophenone and 2,4-dihydroxybenzophenone -Hydroxy benzophenone type ultraviolet absorbers; salicylic acid ester type ultraviolet absorbers such as phenyl salicylate and 4-tert-butyl-phenyl-salicylate; 2-ethyl-hexyl-2-cyano-3,3-diphenyl acrylate, ethyl-2- Cyano-3,3-diphenylacry Cyanoacrylate-based ultraviolet absorbers such as octyl-2-cyano-3,3-diphenylacrylate; 2- (4,6-bis (2,4-dimethylphenyl) -1,3,5-triazine-2 -Yl) -5-hydroxyphenyl, 2- (2,4-dihydroxyphenyl) -4,6-bis- (2,4-dimethylphenyl) -1,3-5-triazine, 2,4-bis [2 Triazine-based ultraviolet absorbers such as -hydroxy-4-butoxyphenyl] -6- (2,4-dibutoxyphenyl) -1,3,5-triazine, tris (hydroxyphenyl) triazine, etc .; an acryloyl group or a benzotriazole skeleton The reaction type ultraviolet absorber etc. which introduce | transduced the methacryloyl group are mentioned. The content of the ultraviolet absorber is, for example, 0.5 to 20 parts by mass, for example, 1 to 10 parts by mass, with respect to 100 parts by mass of the solid content in the pressure-sensitive adhesive composition.

5. Release Sheet In the window film of the present embodiment, a release sheet 18 is further provided on the pressure-sensitive adhesive layer. Examples of the release sheet include those obtained by applying a release agent such as silicone to various plastic films such as polyethylene terephthalate and polypropylene. The thickness of the release sheet is not particularly limited, but is usually about 20 to 150 μm.

6. Characteristics of Window Film (1) UV Transmittance of Window Film According to JIS A 5759 of the window film 1 of the present embodiment, the UV transmittance measured is preferably less than 3%, and less than 1%. It is more preferable that
The reason for this is that the window film can shield the ultraviolet ray more effectively when the value of the ultraviolet ray transmittance is less than 3%.

(2) Haze of Window Film The haze measured according to JIS K 7136: 2000 of the window film 1 of this embodiment should have a value close to that of the substrate film alone and a value of 1.0% or less. Is preferred.
By being configured in this manner, a window film having excellent transparency can be obtained.
When such haze reaches a value exceeding 1.0%, the image seen through the window film may appear to be blurred.
The haze is preferably 1.0% or less, more preferably 0.7% or less, and still more preferably 0.5% or less.
In the window film of the present embodiment, since the hydrophobized silica sol is unevenly distributed on the surface side of the hard coat layer after curing the hard coat layer forming material opposite to the base film, the rise of haze is caused. Can be effectively prevented while the hard coat layer is stuck.

Second Embodiment
In the window film of the second embodiment, a hard coat layer is laminated on one side of a substrate film, an adhesive layer is laminated on the other side of the substrate film, and the adhesive layer is a UV absorber. It is a window film containing, Comprising: The said hard-coat layer consists of hardened | cured material of the hard-coat layer formation material containing at least (A) energy beam curable resin, and (B) hydrophobization silica sol, and said (B) hydrophobicity The silica sol is unevenly distributed on the surface side of the hardcoat layer after curing the hardcoat layer-forming material opposite to the base film, and the hardcoat layer-forming material further comprises (C) leveling Containing the agent.
That is, the window film of the second embodiment is different from the window film of the first embodiment in that the hard coat layer-forming material further contains (C) a leveling agent.
Hereinafter, although the window film of 2nd Embodiment is demonstrated, description is abbreviate | omitted about the point which is common in the window film of the said 1st Embodiment.

(C) Leveling agent (1) -1. Configuration In the window film of the second embodiment, the hard coat layer-forming material contains (C) a leveling agent. It is preferable that the said leveling agent is (C) silicone type leveling agent.
When the hard coat layer-forming material contains (C) a silicone-based leveling agent, carbon atoms, oxygen atoms, and the like measured by XPS analysis in the depth direction in the region from the outermost surface of the hard coat layer to a position of 5 nm. The silicon atom concentration is preferably in the range of 0.2 to 5.0 atom% with respect to the total amount (100 atom%) of silicon atoms.
Generally, it is known that a leveling agent can suppress distortion and repelling of a coating film with respect to a base film by being unevenly distributed in many in the hard coat layer formation material in the outermost surface side.

  FIG. 2: is sectional drawing which shows typically one Embodiment of the window film of 2nd Embodiment. As shown in FIG. 2, in the hard coat layer, as described above, the hydrophobized silica sol is localized on the surface side opposite to the substrate surface, and the silicone-based leveling agent covers the hydrophobized silica sol most. By uneven distribution on the surface in a predetermined amount range, a window film excellent in sticking resistance, blocking resistance and leveling performance can be obtained by the interaction of the hydrophobized silica sol and the silicone-based leveling agent.

  More specifically, as illustrated in FIG. 2, in the hard coat layer, the silicone-based leveling agent is unevenly distributed in the ultrathin film state 17 so as to cover the hydrophobized silica sol in the region farthest from the substrate. Is understood.

Therefore, in the region from the outermost surface of the window film to the position of 5 nm, the silicon atom concentration is 0 with respect to the total amount (100 atom%) of carbon atoms, oxygen atoms, and silicon atoms measured by XPS analysis in the depth direction. By specifying that the value is in the range of 2 to 5.0 atom%, by efficiently controlling the leveling agent present on the outermost surface, the leveling performance, the sticking resistance, and the blocking resistance can be obtained. Can be effectively improved.
That is, when the silicon atom concentration has a value of less than 0.2 atom%, when the hard coat layer forming material is applied, the leveling agent can not form a thin film on the outermost surface of the hard coat layer forming material. However, it may be difficult to form a uniform thin film with distortion and repelling.
On the other hand, when the silicon atom concentration reaches a value exceeding 5.0 atom%, the surface energy of the hard coat surface is reduced, so when forming an adhesive layer or a print layer on the hard coat layer, such an adhesive layer In some cases, the adhesion of the
Therefore, the silicon element concentration in the region from the outermost surface of the window film to the position of 5 nm is more preferably in the range of 1.0 to 5.0 atom%, and in the range of 2.0 to 4.5 atom% It is further preferable to set the value of
In addition, the silicon atom concentration by the elemental analysis measurement of XPS means the silicon atom concentration in each depth measured by the XPS analysis of the depth direction in the whole hard-coat layer.

(1) -2. Type (C) As silicone-based leveling agent, silicone, silicone-modified acrylic, polyether-modified polydimethylsiloxane, polyetherester-modified hydroxyl group-containing polydimethylsiloxane, polyester-modified hydroxyl group-containing polydimethylsiloxane, polyether-modified polydimethylsiloxane It is preferable that it is at least one selected from the group consisting of
The reason for this is that if the leveling agent is such a kind, it becomes easy to make the silicon atom concentration in the leveling agent thin film 17 on the surface of the hard coat layer a value within the above range, and the surface smoothing required for the leveling agent When the adhesive layer or the printing layer is formed on the hard coat layer, the adhesion to the adhesive layer or the like can be improved in a well-balanced manner.
Among the silicone-based leveling agents described above, it is particularly preferable to include a silicone-based leveling agent having a polyether chain.
The reason for this is that if the silicone-based leveling agent is a silicone-based leveling agent having a polyether chain, the printed layer is less likely to be repelled, the leveling property on coating can be ensured, and the slipperiness when winding the substrate Can be easily maintained.
Further, among the above-mentioned silicone-based leveling agents, it is more preferable to include a reactive silicone-based leveling agent having a vinyl group or the like.
The reason for this is that if the silicone leveling agent is a reactive leveling agent, it reacts with the energy ray curable resin and a stronger leveling agent thin film can be formed, so that, for example, the leveling when incorporated in an image display device or the like It is because the contamination etc. which originate in an agent can be reduced.
In addition, about the fluorine-type leveling agent generally made useful as a leveling agent,
In the present invention, although repelling can be suppressed effectively, it is confirmed that the synergetic effect by the silicone-based leveling agent and the hydrophobized silica sol is not expressed because of high water repellency.

(1) -3. Blending Amount Further, it is preferable to further blend the (C) leveling agent at a value within the range of 0.045 to 5 parts by weight with respect to 100 parts by weight of the (A) energy ray-curable resin.
The reason for this is that when the adhesive layer or the printing layer is formed on the hard coat layer, the adhesion with the adhesive layer or the like can be improved by setting the leveling agent to a value within such a range. It is because it can.
More specifically, when the blending amount of the leveling agent is less than 0.045 parts by weight, the uneven distribution of the leveling agent on the outermost surface of the substrate is insufficient, and the coating film of the hard coat layer forming material is distorted, It is because it may become difficult to form a uniform coating film with repelling.
On the other hand, when the compounding amount of the leveling agent exceeds 5 parts by weight, the leveling agent is localized beyond the leveling effect, the surface energy of the hard coat surface is reduced, and the adhesive layer or printing is carried out When the layer is formed, even if the adhesive layer or the like is laminated, the adhesive layer or the like may be subsequently detached.
Therefore, it is more preferable to set the compounding amount of (D) leveling agent to a value within the range of 0.05 to 3 parts by weight, and more preferably to a value within the range of 0.05 to 2 parts by weight, 0 It is particularly preferable to set the value within the range of 0.55 to 0.5 parts by weight.

<< Method of manufacturing window film >>
First Embodiment
In one embodiment, the present invention
A method for producing a window film comprising a hard coat layer laminated on one side of a substrate film and an adhesive layer on the other side of the substrate film, which comprises the following steps (1) to (3) The present invention provides a method of manufacturing a window film characterized by
(1) A step of forming a hard coat layer forming material containing at least (A) energy ray curable resin and (B) hydrophobized silica sol on one side of the base film (2) forming the hard coat layer A hard coat layer in which the material is cured and the (B) hydrophobized silica sol is unevenly distributed on the surface side of the hard coat layer after curing the hard coat layer forming material opposite to the base film. (3) forming an adhesive layer containing a UV absorber on the other side of the base film

The window film manufacturing method of the present embodiment can be suitably used as the window film manufacturing method of the first embodiment. In addition, the manufacturing method of the window film of this invention is not limited to the manufacturing method of the window film demonstrated below.
Hereinafter, the base film and the hard coat layer to be used can be the same as the contents of the window film of the first embodiment, and therefore, the matters related to the method of manufacturing the window film will be mainly described.

Step (1-1): Preparation Step of Hard Coat Layer-Forming Material Step 1-1 prepares a hard coat layer-forming material containing at least (A) an energy ray-curable resin and (B) a hydrophobized silica sol. It is a process.
More specifically, it is a step of uniformly mixing the above-mentioned hard coat layer forming material and a dilution solvent.
Examples of the solvent include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, pentyl alcohol, ethyl cellosolve, benzene, toluene, xylene, ethyl benzene, cyclohexane, ethyl cyclohexane, ethyl acetate, Examples include butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, tetrahydrofuran, propylene monomethyl ether, water and the like, and two or more solvents may be combined.
In particular, propylene monomethyl ether, toluene, methyl ethyl ketone, ethyl acetate, n-butyl acetate, cyclohexanone, methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, since energy ray curable resins such as acrylic monomers can be easily dissolved. It is preferable to use n-butyl alcohol, isobutyl alcohol, pentyl alcohol and the like.
In addition, about the structure of a predetermined | prescribed hard-coat layer forming material, since it is as having already described, it abbreviate | omits.

Step (1-2): Coating Step of Hardcoat Layer-Forming Material on Base Film Step 1-2 is a step of coating the hardcoat layer-forming material on one side of the base film.
More specifically, the base film 10 is prepared, and the hard coat layer forming material prepared in the step (1) is placed on the hard coat layer in a thickness range of 0.5 to 10 μm after curing. It is the process of coating so that it may become the value of.
In addition, it does not restrict | limit in particular about the coating method of a hard-coat layer formation material, For example, the well-known method, for example, the bar coat method, the gravure coat method, the knife coat method, the roll coat method, the blade coat method, the die coat method etc. Can be used.

Step (2): Hardening of Hardcoat Layer Forming Material and Hardcoat Layer Forming Step 2 is curing the above-mentioned hardcoat layer forming material, and (B) the hydrophobized silica sol is the substrate film of the hardcoat layer It is a process of forming a hard coat layer unevenly distributed on the opposite surface side.
More specifically, it is preferable that the coated material of the hard coat layer forming material obtained by evaporating the solvent after the drying step be irradiated with an energy ray such as an ultraviolet ray or an electron beam to be cured.
When implemented in this manner, the hard coat layer can be formed rapidly, and can be firmly adhered to the base film.
Further, the hydrophobized silica sol can be effectively localized on the surface side opposite to the base film of the hard coat layer.
When the hard coat layer forming material contains a silicone-based leveling agent, the silicone-based leveling agent can be further localized on the outermost surface, and the silicon atom concentration on the outermost surface is at a position 5 nm from the outermost surface of the window film. In the region, the silicon atom concentration is adjusted within the range of 0.2 to 5.0 atom% with respect to the total amount (100 atom%) of carbon atoms, oxygen atoms, and silicon atoms measured by XPS analysis in the depth direction Becomes easy.
Therefore, the mechanical strength of the hard coat layer can be improved, and sticking and blocking of the hard coat layer can be effectively prevented, and when an adhesive layer or a printing layer is formed on the hard coat layer, Adhesiveness with such a printing layer etc. can be improved.

Moreover, in forming a hard-coat layer, when irradiating an ultraviolet-ray, for example, it is preferable to make the irradiation amount (integrated light quantity) with respect to a hard-coat layer formation material into the value within the range of 100-1000 mJ / cm < ² >.
The reason for this is that when the UV irradiation amount is less than 100 mJ / cm ² , curing of the hard coat layer may be insufficient.
On the other hand, if the UV irradiation amount exceeds 1000 mJ / cm ² , the hard coat layer and the base film may be deteriorated by the ultraviolet light.
In addition, there is no restriction | limiting in particular about the kind of energy-beam irradiation apparatus to be used, For example, the ultraviolet irradiation apparatus using a high pressure mercury lamp, a xenon lamp, a metal halide lamp, a fusion H lamp etc. etc. can be used.

Step (3): Step of Forming Pressure-Sensitive Adhesive Layer Step 3 is a step of forming a pressure-sensitive adhesive layer containing an ultraviolet light absorber on the other side of the base film.
First, the pressure-sensitive adhesive layer-forming material and the solvent are uniformly mixed.
Examples of the solvent for dissolving or dispersing the pressure-sensitive adhesive forming material include aliphatic hydrocarbons such as hexane, heptane and cyclohexane, aromatic hydrocarbons such as toluene and xylene, halogenated hydrocarbons such as methylene chloride and ethylene chloride, methanol, Alcohols such as ethanol, propanol and butanol; ketones such as acetone, methyl ethyl ketone, 2-pentanone and isophorone; esters such as ethyl acetate and butyl acetate; and cellosolve solvents such as ethyl cellosolve.

More specifically, as shown in FIG. 1, after the hard coat layer 12 is formed on one surface 10 a of the base film 10, a step of forming the pressure-sensitive adhesive layer 14 on the other surface 10 b of the base film 10 It is.
In addition, since the application process is the same as the process of the above-mentioned hard-coat layer formation, the details are omitted.

  In addition, although the case where an adhesive layer forming material was apply | coated to a base film was illustrated in this embodiment, the said adhesive layer forming material can be said by bonding together the adhesive layer formed beforehand to a base film, You may form in the other side of the said base film in which the said hard-coat layer is not laminated | stacked.

  By carrying out in this way, even when the window film is manufactured by Roll To Roll, the hard coat layer can be effectively prevented from sticking to the adjacent other layer, and the productivity is improved. Can be improved.

  Hereinafter, the present invention will be described in more detail by way of examples. However, the following description exemplifies the present invention, and the present invention is not limited to these descriptions.

Example 1
1. Preparation of Window Film (1) Preparation Step of Hard Coat Layer-Forming Material As shown in Table 1, energy beam curable resin as component (A), hydrophobized silica sol as component (B), and component (C) The hard coat layer forming material of Example 1 was prepared from the silicone type leveling agent as and the photopolymerization initiator as the component (D).
More specifically, 100 parts by weight of a mixture of (a1) pentaerythritol triacrylate and pentaerythritol tetraacrylate (manufactured by Toagosei Co., Ltd., Alonix M-305) as component (A), and photopolymerization as component (D) 10 parts by weight of an initiator (Ciba Specialty Chemicals, Irgacure 184), a hydrophobized silica sol as component (B) (CIK Nanotech, SIRPGM 15WT% -E26, average particle size 30 nm, solid content concentration 15%) 3 0.3 parts by weight of silicone (DOW CORNING (R) 8032 ADDITIVE manufactured by Toray Dow Corning Co., Ltd.) as a silicone-based leveling agent as component (C), 80 parts by weight of propylene glycol monomethyl ether as a dilution solvent, Diluted with 80 parts by weight of toluene Then, the hard coat layer forming material (solid content concentration 40% by weight) was adjusted.

(2) Coating step of hard coat layer forming material Then, using the hard coat layer forming material as a base film, on one side of a PET film with an easy adhesion layer (film thickness 50 μm) having an easy adhesion treatment on both sides. It applied so that the film thickness after drying might be set to 2 micrometers using a Meyer bar.

(3) Drying process Then, the dilution solvent contained in the hard court layer formation material applied to a substrate film was removed.
That is, it heat-dried on 70 degreeC and the conditions for 1 minute using the hot air dryer, and fully removed the dilution solvent.

(4) Curing Step Subsequently, ultraviolet ray was irradiated at 100 mJ / cm ² using a high pressure mercury lamp to photocure the hard coat layer forming material to form a hard coat layer.

(5) Preparation step of pressure-sensitive adhesive layer-forming material 100 parts by weight of acrylic acid ester copolymer as a pressure-sensitive adhesive, 4.0 parts by weight of Ciasorb UV-24 (manufactured by Nippon Cytech Industries, Ltd.) as a UV absorber, and as a dilution solvent MEK was mixed with 8 parts by weight.

(6) Application Step of Pressure-Sensitive Adhesive Layer-Forming Material Subsequently, the pressure-sensitive adhesive layer-forming material was applied to one side of a release sheet (film thickness 38 μm) using a knife coater so that the film thickness after drying was 20 μm. .

(7) Drying Step Subsequently, the dilution solvent contained in the pressure-sensitive adhesive layer-forming material applied to the release sheet was removed.
That is, it heat-dried on 70 degreeC and the conditions for 1 minute using the hot air dryer, and fully removed the dilution solvent.

(8) Bonding process The obtained adhesive layer and the base film in which the hard-coat layer was formed were bonded together, and the window film of Example 1 was obtained.

2. Evaluation of Window Film (1) Analysis of Silicon Atom Concentration Carbon Atom Measured by XPS Analysis in the Depth Direction of the Hard Coat Layer in the Window Film Obtained Using an XPS Measurement Analyzer (Quantum 2000, manufactured by ULVAC-PHI, Inc.) Elemental analysis of oxygen atoms and silicon atoms was performed. From the measurement, in the region from the outermost surface to the position of 5 nm, the silicon atom concentration was calculated with respect to the total amount (100 atom%) of carbon atoms, oxygen atoms, and silicon atoms. The obtained results are shown in Table 1.

(2) Measurement of hydrophobization degree of silica sol coating Hydrophobicized silica sol A (solid content concentration 15%) dispersed in methyl isobutyl ketone was added to a PET film (Lumirror T-60 manufactured by Toray Industries, film thickness 100 μm) Mayer bar It coated with # 8.
Next, it was dried in an oven at 90 ° C. for 1 minute to obtain a silica sol coating film having a thickness of 1 μm after drying.
Next, the contact angle of water measured in accordance with JIS R 3257 on the silica sol coating film was measured to evaluate the degree of hydrophobicity.
That is, when a PET film having a silica sol coating film formed on a flat glass substrate is allowed to stand and the inclination of the glass substrate is 0 degree, 2 μL of water droplets are dropped, and when the droplets stand still, Young's equation The water contact angle was determined by The obtained results are shown in Table 1.

(3) Evaluation of the adhesion of the hard coat layer A UV curable ink (UVPAL 911 black, manufactured by Teikoku Ink Mfg. Co., Ltd.) is applied to the surface of the obtained window film, and the UV is irradiated to cure the ink. A printing layer having a thickness of 1 μm was formed. The surface of the printing layer is cross-cut with 1 mm width in a grid pattern, and an adhesive tape (manufactured by Nichiban Co., Ltd., Sellotape (registered trademark)) is applied to the surface of the printing layer cross-cut in a grid pattern. Cellotape (registered trademark) peeling test was conducted according to the cross-cut tape method of -5-6 (cross-cut method), and the print adhesion of the curable resin layer was evaluated according to the following criteria. The obtained results are shown in Table 1.
:: There is no printing layer to be peeled off from the window film and transferred to the adhesive tape.
Fair: The number of printing layers transferred to the adhesive tape is less than 50%.
X: The number of printing layers transferred to the adhesive tape is 50% or more.

(4) Evaluation of sticking resistance (4-1)
A window film piece obtained by cutting out the window film to a size of 60 × 60 cm and a PET film (film thickness 50 μm) used as a base film of the window film of Example 1 were overlapped. Under the present circumstances, it laminated | stacked so that the hard-coat layer (HC) of a window film piece and PET film may be planarly contacted.
Immediately after the superposition, the dynamic friction was measured in accordance with the JIS-K 7125 plastic-film and sheet-friction coefficient test method. Under a load of 1 kg / 60cm ² in window film piece and a PET film, by moving the window film piece at a test speed of 10 mm / min, to evaluate dynamic friction force _{F D.} The obtained results are shown in Table 1.
(4-2)
A window film piece obtained by cutting out the window film to a size of 60 × 60 cm and a sputtered film (film thickness 50 μm) were superposed. Under the present circumstances, it laminated | stacked so that the hard-coat layer (HC) of a window film piece and a sputter | spatter film might be planarly contacted. The sputtered film is a non-slippery substrate.
Immediately after superposition, dynamic friction was measured in accordance with the JIS-K 7125 plastic-film and sheet-friction coefficient test method. Under a load of window film pieces and a sputtering film 1 kg / 60cm ^2, by moving the window film piece at a test speed of 10 mm / min, to evaluate dynamic friction force _{F D.} The obtained results are shown in Table 1. In the comparative examples 1 to 4, since zipping had occurred, it was shown as (mean of minimum value of dynamic friction force-average of maximum value of dynamic friction force).

(5) Arithmetic mean roughness Ra
Arithmetic mean roughness (Ra) on the surface of the hard coat layer of the obtained window film was measured using a surface roughness measuring device (Wyko NT1100, manufactured by Bico) in accordance with JIS B 0601-1994. The obtained results are shown in Table 1.

(6) Haze The haze of the obtained window film was measured using a haze meter (NDH-5000 manufactured by Nippon Denshoku Industries Co., Ltd.) in accordance with JIS K7136: 2000. The obtained results are shown in Table 1.

(7) Ultraviolet transmittance The transmittance of ultraviolet light of wavelength 300 to 380 nm of the obtained window film is measured according to JIS A 5759 using an ultraviolet visible near infrared spectrophotometer (UV-3600 manufactured by Shimadzu Corporation) Measured. The obtained results are shown in Table 1.

Example 2
In Example 2, the window film was produced and evaluated by the method similar to Example 1 except having changed the compounding quantity of (B) hydrophobization silica sol into 3 weight parts, and having mix | blended 5 weight parts. The obtained results are shown in Table 1.

[Example 3]
In Example 3, the window film was produced and evaluated by the method similar to Example 1 except having changed the compounding quantity of (B) hydrophobization silica sol into 3 weight parts, and having mix | blended 10 weight parts. The obtained results are shown in Table 1.

Example 4
In Example 4, (C) the leveling agent was not blended, and the compounding amount of the (D) photopolymerization initiator was only 5 parts by weight of the photopolymerization initiator (Ciba Specialty Chemicals Inc. Irgacure 184), A window film was produced and evaluated in the same manner as in Example 3 except that the solution was diluted with 160 parts by weight of propylene glycol monomethyl ether as a dilution solvent. The obtained results are shown in Table 1.

Comparative Example 1
In Comparative Example 1, a window film was produced in the same manner as in Example 4 except that the window film was produced in the same manner as in Example 3 except that (B) the hydrophobized silica sol was not blended. And evaluated. The obtained results are shown in Table 1.

Comparative Example 2
In Comparative Example 2, 10 parts by weight of silica sol (Nissan Chemical Industries, IPA-ST, average particle diameter 10 to 20 nm, solid content concentration 30%) is blended instead of (B) hydrophobized silica sol, and toluene is used as a dilution solvent A window film was produced and evaluated in the same manner as in Example 4 except that the solution was diluted with 160 parts by weight. The obtained results are shown in Table 1.

Comparative Example 3
In Comparative Example 3, silica sol (Nissan Chemical Industries, IPA-ST, average particle diameter 10 to 20 nm) is replaced with silica sol (Nissan Chemical Industries, IPA-ST-L, average particle diameter 40 to 50 nm, solid content concentration A window film was produced and evaluated in the same manner as in Comparative Example 2 except that 30% was blended. The obtained results are shown in Table 1.

Comparative Example 4
In Comparative Example 4, silica sol (manufactured by Nissan Chemical Industries, Ltd., IPA-ST-ZL, manufactured by Nissan Chemical Industries, IPA-ST-ZL, average particle diameter of 70-100 nm, solid) in place of silica sol (manufactured by Nissan Chemical Industries, IPA-ST-L, average particle diameter 40-50 nm) A window film was produced and evaluated in the same manner as in Comparative Example 2 except that the component concentration was 30%). The obtained results are shown in Table 1.

The window films of Examples 1 to 4 in which hydrophobized silica sol was blended in the hard coat layer were excellent in sticking resistance, and were also excellent in light transmittance and image clarity.
However, the window films of Comparative Examples 1 to 4 in which the hydrophobized silica sol was not blended in the hard coat layer were inferior in sticking resistance. Such window films are considered to be difficult to roll up the film.

As described above, according to the window film of the present invention, the hard coat layer is laminated on one side, the pressure-sensitive adhesive layer is laminated on the other side of the base film, and the pressure-sensitive adhesive layer is ultraviolet light. A window film containing an absorbent, wherein the hard coat layer comprises a cured product of a hard coat layer-forming material comprising a hydrophobized silica sol, and the hydrophobized silica sol comprises a base film and a hard coat layer in the hard coat layer. As a result of being unevenly distributed on the opposite surface side, a window film in which the sticking of the hard coat layer is effectively prevented can be obtained.
The window film of the present invention can be effectively used for window glass of automobiles, buildings and the like.

1, 2, 3: Window film 10: base film 10a, 10b: surface 12: hard coat layer 14: adhesive layer 14b: surface 16: hydrophobized silica sol 17: leveling agent thin film 18: release sheet 19: hydrophilic silica sol

Claims (11)

A hard coat layer is laminated on one side of the substrate film,
It is a window film provided with an adhesive layer containing a UV absorber on the other side of the substrate film,
The hard coat layer comprises a cured product of a hard coat layer-forming material containing at least (A) an energy ray-curable resin and (B) a hydrophobized silica sol,
The compounding amount of the (B) hydrophobized silica sol is in the range of 0.1 to 25 parts by weight in terms of solid content with respect to 100 parts by weight of the (A) energy ray-curable resin,
A window film characterized in that (B) the hydrophobized silica sol is unevenly distributed on the surface side of the hard coat layer after curing the hard coat layer-forming material opposite to the base film.   The window film according to claim 1, wherein the hard coat layer-forming material further comprises (C) a leveling agent.   The (C) leveling agent is selected from the group consisting of silicone, silicone-modified acrylic, polyether-modified polydimethylsiloxane, polyetherester-modified hydroxyl group-containing polydimethylsiloxane, polyester-modified hydroxyl group-containing polydimethylsiloxane, and polyether-modified polydimethylsiloxane. The window film according to claim 2, wherein the window film is at least one selected from the group consisting of   The compounding amount of the (C) leveling agent is a value within the range of 0.045 to 5 parts by weight in terms of solid content with respect to 100 parts by weight of the (A) energy ray-curable resin. Item 4. The window film according to item 2 or 3.   The window film according to any one of claims 1 to 4, wherein the average particle diameter of the (B) hydrophobized silica sol is a value within the range of 10 to 100 nm.   The contact angle of water measured according to JIS R 3257 with respect to the coating film when the (B) hydrophobized silica sol is formed into a coating film is a value of 100 ° or more. The window film according to any one of the preceding claims. The window film according to any one of claims 1 to 6 , wherein the transmittance of ultraviolet light having a wavelength of 300 to 380 nm measured according to JIS A 5759 of the window film is less than 3%. . The window film according to any one of claims 1 to 7 , wherein a haze measured according to JIS K 7136: 2000 of the window film is 1.0% or less. Any The arithmetic average roughness Ra measured according to JIS B 0601-1994 in the surface of the hard coat layer, according to claim 1-8, characterized in that a value within a range of 1.5~5nm The window film according to one of the claims. The window film according to any one of claims 1 to 9 , wherein a dynamic friction force between the hard coat layer and the base film measured according to JIS K 7125 is 15 N or less. . A method for producing a window film, wherein a hard coat layer is laminated on one side of a substrate film, and an adhesive layer is provided on the other side of the substrate film,
The manufacturing method of the window film characterized by including following process (1)-(3).
(1) A step of forming a hard coat layer forming material containing at least (A) energy ray curable resin and (B) hydrophobized silica sol on one side of the base film (2) forming the hard coat layer material is cured, the (B) hydrophobic silica sol, of the hard coat layer-forming material wherein the hard coat layer after curing, and wherein the substrate film is unevenly distributed on the opposite surface of the ( B) A step of forming a hard coat layer in which the amount of the hydrophobized silica sol is in the range of 0.1 to 25 parts by weight in terms of solid content with respect to 100 parts by weight of the (A) energy ray-curable resin (3) A step of forming a pressure-sensitive adhesive layer containing a UV absorber on the other side of the base film

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