JP7685919B2 - Manufacturing method and manufacturing device for laminated film - Google Patents

Description

The present invention relates to a method and an apparatus for manufacturing a laminated film.

In order to make displays such as those for smartphones more flexible, flexible film materials are being considered as an alternative to rigid glass materials. Furthermore, the use of a layer to impart fingerprint resistance (hereinafter sometimes referred to as AF: Anti-Fingerprint) properties as a layer to be formed on the outermost surface of such film materials is being considered.

Conventional methods proposed for coating such anti-fingerprint layers onto film materials include forming an AF layer by vapor deposition, applying an AF layer by spray coating, and forming a coating film on a base film using a coating roll.

Among these, the gravure coating method is known as a method for forming a coating film on a base film using a coating roll. This method includes a coating step in which a coating liquid is applied to a base film using a gravure roll to form a coating film. The gravure roll is a roll having recesses formed on its circumferential surface for holding the coating liquid. In the coating step, when the coating liquid is supplied to the gravure roll, the coating liquid is temporarily held in the recesses. Then, the gravure roll comes into contact with the base film that is being continuously transported, and the coating liquid in the recesses is applied to the base film.

Patent Document 1 discloses a technology for a gravure coating method that uses a gravure roll that has spiral oblique cells on the roll surface and whose outermost surface is coated with diamond-like carbon. In addition, Patent Document 2 discloses a technology for irradiating a substrate film with plasma before applying a coating liquid.

JP 2015-223552 A JP 2010-125358 A

However, when applying an anti-fingerprint layer to a base film, the techniques disclosed in Patent Documents 1 and 2 both made it difficult to form a highly accurate, uniform coating film, and there was room for improvement in the appearance and scratch resistance of the coating film.

One aspect of the present invention aims to realize a manufacturing method and manufacturing apparatus for a laminated film that can form a uniform coating film that has excellent appearance and scratch resistance.

In order to solve the above problems, one aspect of the present invention has the following configuration.

(1) A method for producing a laminated film, comprising a coating step of applying a coating liquid onto a base film using a gravure roll to form a coating film, wherein in the coating step, a ratio (Vr/Vf) of a rotation speed (Vr) of the gravure roll to a conveyance speed (Vf) of the base film is 30 to 60, and an amount of water vapor in the coating step is 10 to 25 g/ ^m3 .

(2) The method for manufacturing a laminated film according to (1), in which the gravure roll and the substrate film transport roll rotate in different directions.

(3) A method for producing a laminated film according to (1) or (2), comprising a drying step for drying the coating film formed in the coating step.

(4) A method for manufacturing a laminated film according to any one of (1) to (3), in which the coating liquid contains a solvent and a resin soluble in the solvent, the solids concentration of the coating liquid is 0.05 to 0.5%, the viscosity of the coating liquid is 0.1 to 100 mPa·s, and the thickness of the coating film is 10 to 50 nm.

(5) The method for producing a laminated film according to any one of (1) to (4), wherein the coating liquid is a fluorine-based coating liquid.

(6) The method for manufacturing a laminated film according to any one of (1) to (5), wherein the coating film is an anti-fingerprint layer.

(7) A laminated film manufacturing apparatus having a coating unit equipped with a gravure roll that applies a coating liquid to a base film transported by a transport roll to form a coating film, wherein the ratio (Vr/Vf) of the rotation speed (Vr) of the gravure roll to the transport speed (Vf) of the base film is set to 30 to 60, and the amount of water vapor in the coating unit is adjusted to 10 to 25 g/ ^m3 .

According to one aspect of the present invention, a uniform coating film can be formed, and a coating film with excellent appearance and scratch resistance can be formed.

1 is a cross-sectional view showing an example of the configuration of a coating device used in a coating step of a laminated film manufacturing method according to an embodiment of the present invention.

The following describes in detail the embodiments of the present invention. However, the present invention is not limited to these, and various modifications are possible within the scope described. The technical scope of the present invention also includes embodiments obtained by appropriately combining the technical means disclosed in the different embodiments and examples. In this specification, unless otherwise specified, "A to B" indicating a numerical range means "A or more (including A and larger than A) or B or less (including B and smaller than B)."

[Technical idea of one embodiment of the present invention]
In coating an anti-fingerprint layer on a base film (optical film), the manufactured laminated film is required to have AF characteristics and appearance that can replace glass materials. Due to the balance with flexibility, the hardness of the base film itself is low. Furthermore, the surface of the base film has irregularities of 1 to 2 μm, which causes the base film to have uneven thickness. For this reason, in coating an anti-fingerprint layer on a base film, the coating film cannot be uniformly applied, making it difficult to achieve satisfactory AF characteristics and appearance.

The coating liquid for the anti-fingerprint layer is very susceptible to becoming cloudy, and is easily affected by the coating method and the unevenness of the base film. If there are locally thick areas on the coated surface of the base film, the coating will become cloudy, while areas with a thin thickness will have a drawback in terms of scratch resistance.

In addition, to coat the fingerprint-resistant layer on the base film, it is preferable to coat a thin film with a thickness of about 10 to 30 nm with high precision. When coating the fingerprint-resistant layer using the gravure coating method, the challenge is to produce a uniform coating film with excellent appearance and scratch resistance with high precision in a roll-to-roll manner. In particular, even if the thickness of the fingerprint-resistant layer differs by a few nm, it becomes cloudy to a degree that can be seen with the naked eye, resulting in poor appearance. For this reason, it is necessary to apply high shear to the coating liquid during gravure coating.

In the technology described in Patent Document 2, there is only a possibility of using a gravure roll as a pick-up roll, and the roll for coating the substrate is a rubber roll. In addition, the technology described in Patent Document 2 assumes coating of metal substrates, and does not require coating precision for optical films. Furthermore, in the technology described in Patent Document 2, the ratio (Vr/Vf) of the rotation speed (Vr) of the gravure roll as a pick-up roll to the conveying speed (Vf) of the substrate film is less than 3, so a uniform AF coating film cannot be produced with high precision.

The inventors therefore conducted extensive research into the gravure coating method, which can produce a uniform coating film with excellent appearance and scratch resistance with high precision. As a result, they discovered that a uniform coating film can be formed by (i) setting the ratio (Vr/Vf) of the rotation speed (Vr) of the gravure roll to the transport speed (Vf) of the base film within a specific range, and (ii) setting the amount of water vapor in the coating process within a specific range, and thus arrived at the embodiment of the present invention.

In high-speed gravure coating as in (i) above, the contact area between the base film and the gravure roll becomes statically charged, causing bead disturbance. In this embodiment, the technical significance of adjusting the amount of water vapor in the coating process is to suppress such bead disturbance. That is, in this embodiment, by performing high-speed gravure coating as in (i) above, it has become necessary for the first time to adjust the amount of water vapor in the coating process in order to suppress the disturbance of the bead portion.

[One embodiment of the present invention]
Hereinafter, one embodiment of the present invention will be described in detail.

<Method of manufacturing the laminated film according to the present embodiment>
The manufacturing method of the laminated film according to the present embodiment (hereinafter, may be referred to as the present manufacturing method) has a coating step of applying a coating liquid onto a base film using a gravure roll to form a coating film, and at least (i) in the coating step, the ratio (Vr/Vf) of the rotation speed (Vr) of the gravure roll to the transport speed (Vf) of the base film is 30 to 60, and (ii) the amount of water vapor in the coating step is 10 to 25 g/ ^m3 .

(Base film)
The substrate film used in this manufacturing method is a film or sheet-like substrate having a uniform thickness and flexibility formed into a long strip shape. The material constituting the substrate is not particularly limited, and may be, for example, resin, paper, cloth, metal, etc., and may be appropriately selected according to the application. When the material constituting the substrate film is a resin, specific examples of the material include polyolefin-based resins such as polyethylene, polypropylene, and polycyclic olefin; acrylic resins; cellulose-based resins; polyamide-based resins such as nylon 6 and nylon 6,6; polyester-based resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polycarbonate; polyimide; and mixtures of these resins. When the laminated film is used as a display for a smartphone or the like, among these resins, the material of the substrate film is preferably a polyimide-based resin.

(Coating process)
The coating step in the present manufacturing method may be a step of applying a coating liquid onto a substrate film using a gravure roll to form a coating film. More specifically, in the coating step, the substrate film surface is continuously coated with the coating liquid using the gravure roll while the strip-shaped substrate film is continuously transported by a transport roll. The gravure roll is a rotating body that rotates with the coating liquid attached (held) on its peripheral surface. When the gravure roll comes into contact with the substrate film surface, the coating liquid attached to the gravure roll is transferred to the substrate film surface.

Figure 1 is a cross-sectional view showing an example of the configuration of a coating device used in the coating process of this manufacturing method.

As shown in FIG. 1, the coating device 10 includes transport rolls F1 and F2, a coating liquid tank H, a gravure roll 3, pressure rolls 5A and 5B, and a blade 6. The coating device 10 also includes a chamber 7 that contains at least the gravure roll 3 and the substrate film 1 that contacts the gravure roll 3. The chamber 7 constitutes the coating section of the coating device 10.

The gravure roll 3 has a rotating shaft 3A and is a rotating body that rotates in contact with the coating liquid 2 in the coating liquid tank H. The gravure roll 3 and the transport rolls F1 and F2 have different rotation directions. That is, the gravure roll 3 rotates in reverse with respect to the transport direction of the base film 1 by the transport rolls F1 and F2. The surface of the gravure roll 3 has fine recesses for liquid storage. In the coating device 10, the coating liquid 2 is transferred from the gravure roll 3 to the base film 1 that is continuously transported by the transport rolls F1 and F2, and a coating film 4 is formed on the back surface of the base film 1. The width of the gravure roll 3 is larger than the width of the base film 1. Therefore, the gravure roll 3 contacts the entire width of the base film 1. Therefore, the gravure roll 3 can transfer the coating liquid 2 to the entire width of the base film 1.

The pressure rolls 5A and 5B are configured to press the back surface of the substrate film 1 that contacts the gravure roll 3 toward the gravure roll 3 by adjusting their positions. The pressure rolls 5A and 5B maintain the contact state between the substrate film 1 and the gravure roll 3 as they are continuously transported.

The tip of the blade 6 is positioned facing the surface of the gravure roll 3 on which the coating liquid 2 is attached before being transferred to the base film 1. The tip of the blade 6 is in contact with the surface of the gravure roll 3. The width of the tip of the blade 6 is greater than the width of the base film 1. The tip of the blade 6 comes into contact with the coating liquid 2 attached to the surface of the gravure roll 3 over a width equal to or greater than the width of the base film 1, thereby making it possible to level the thickness of the film of the coating liquid 2 on the surface of the gravure roll 3.

In addition, in the coating device 10, steam is supplied into the chamber 7. By adjusting the amount of steam supplied to the chamber 7, the amount of steam during the coating process is adjusted.

In this manufacturing method, the coating process can be carried out, for example, by operating the coating device 10. In this coating process, the coating liquid 2 is continuously applied to the surface of the base film 1 by the gravure roll 3 while the belt-shaped base film 1 is continuously transported by the transport rolls F1 and F2. Specifically, in this coating process, the following steps (i) to (iii) are continuously carried out. Step (i) is to supply the coating liquid 2 from the coating liquid tank H to the gravure roll 3, adhere the coating liquid 2 to the surface of the gravure roll 3, and rotate the gravure roll 3. Step (ii) is to make the thickness of the film of the coating liquid 2 uniform by bringing the coating liquid 2 adhering to the surface of the rotating gravure roll 3 into contact with the blade 6. Step (iii) is to transfer the film of the coating liquid 2, the thickness of which has been made uniform in step (ii), to the base film 1 by further rotating the gravure roll 3 and bringing it into contact with the base film 1.

As described above, the pressure rolls 5A and 5B maintain the contact state between the continuously transported base film 1 and the gravure roll 3. Therefore, by carrying out the steps (i) to (iii) above, the coating liquid 2 sandwiched between the base film 1 and the gravure roll 3 forms a bead portion 2A (liquid pool) while rotating between the base film 1 and the gravure roll 3, and maintains a stable state. By maintaining the bead portion 2A in a stable state in this way, a stable coating film 4 can be formed on the base film 1.

The coating device used in the coating process is not limited to the configuration shown in FIG. 1, and may be configured to be capable of coating using a gravure roll. For example, in the coating process, the gravure roll and the transport roll may have the same rotation direction. From the viewpoint of keeping the bead portion in a stable state, it is preferable that the gravure roll and the transport roll have different rotation directions.

In the present manufacturing method, in the coating step using the above-mentioned coating device, particularly the coating device shown in Fig. 1, (i) the ratio (Vr/Vf) of the rotation speed (Vr) of the gravure roll to the transport speed (Vf) of the base film is 30 to 60, and (ii) the amount of water vapor in the coating step is 10 to 25 g/ ^m3 . The coating step is high-speed gravure coating in which the gravure roll rotates at a higher speed than the transport speed (Vf) of the base film. The numerical range of the amount of water vapor corresponds to a humidity of about 70 to 80%.

By setting the Vr/Vf and the amount of water vapor within the above numerical ranges, (a) the bead portion can be kept in a stable state, and (b) a high shear force can be applied from the gravure roll rotating at high speed to the coating liquid applied to the substrate film. As a result, a uniform coating film can be formed, and a coating film with excellent appearance and scratch resistance can be formed.

In high-speed gravure coating that satisfies the above-mentioned Vr/Vf range, the contact area between the substrate film and the gravure roll is charged with static electricity. This charging causes the beat portion to become unstable and disordered. In order to suppress the disorder of the beat portion due to this charging, it is necessary to adjust the amount of water vapor in the coating process to the above-mentioned numerical range. The method for adjusting the amount of water vapor in the coating process is not particularly limited. For example, when the coating device shown in FIG. 1 is used, the amount of water vapor supplied to the chamber 7 is adjusted. In addition, the device for adjusting the amount of water vapor in the chamber 7 can be a known humidity control device and is not particularly limited. For example, the amount of water vapor can be suitably adjusted by adjusting the humidity of the gas phase in the chamber by connecting a precision air conditioner to the coating device.

The Vr/Vf ratio is preferably 32 to 55, and more preferably 34 to 50.

In this manufacturing method, the rotation speed (Vr) of the gravure roll is 3 to 100 m/min, preferably 10 to 70 m/min, and more preferably 15 to 30 m/min. The transport speed (Vf) of the base film is 0.1 to 10 m/min, preferably 0.3 to 5 m/min, and more preferably 0.5 to 2 m/min. By having the rotation speed (Vr) of the gravure roll and the transport speed (Vf) of the base film within the above numerical ranges, a high shear force is applied to the coating film, and a highly accurate uniform film with excellent appearance and properties can be continuously produced.

The amount of water vapor is preferably 12 to 24 g/ ^m3 , and more preferably 15 to 20 g/ ^m3 .

(drying process)
The present manufacturing method may include a drying step of drying the coating film formed in the coating step. For example, using a coating device as shown in FIG. 1, a coating liquid is transferred to a substrate film to form a coating film, and then the solvent in the coating film is removed in the drying step, and the coating film is dried and cured. The method for drying and curing the coating film in the drying step may be a known drying method used in gravure coating technology, as long as it can remove the solvent in the coating film and dry and cure the coating film.

(Coating Fluid)
The coating solution used in the present production method contains a solvent and a resin soluble in the solvent. The soluble resin is not particularly limited as long as it can be applied to a substrate film and then dried and cured to form a coating film.

Specific examples of the resin used in the coating liquid include polyurethane, polycycloolefin, polycarbonate, polyester, polyetherketone, polyamide, polyimide, fluororesin, and mixtures of these resins. In particular, examples of the fluororesin include perfluoroalkyl group-containing compounds having an alkoxysilyl group in the molecule, and fluoroalkyl ether oligomers. In addition, when the coating film formed in the coating process is an anti-fingerprint layer, the coating liquid is preferably a fluorine-based coating liquid containing the above-mentioned fluororesin.

The solvent used in the coating liquid is one that can dissolve or disperse the resin. Therefore, in the coating liquid, the resin may be dissolved in the solvent or dispersed as a solid. The solvent may be one that can dissolve or disperse the resin, and can be appropriately selected depending on the resin and substrate film used. Examples of the solvent include halogenated hydrocarbons such as dichloromethane and dichloroethane; phenols such as phenol and p-chlorophenol; alcohols such as methanol and ethanol; aromatic hydrocarbons such as benzene and toluene; acetone; ethyl acetate; ethylene glycol monomethyl ether; diethylene glycol dimethyl ether; methyl isobutyl ketone; methyl ether ketone; cyclohexane; cyclopentanone; water; hydrofluoroether, etc. These solvents may be used alone or in appropriate combination of two or more. In particular, when the coating liquid is a fluorine-based coating liquid, the solvent may be hydrofluoroether.

The solids concentration of the coating liquid is preferably 0.05 to 0.5%, and more preferably 0.1 to 0.3%. By having the solids concentration of the coating liquid within the above numerical range, it is possible to reduce significant flow before drying after coating, and also to obtain a sufficient leveling effect before drying.

The viscosity of the coating liquid is preferably 0.1 to 100 mPa·s, more preferably 0.3 to 50 mPa·s, and even more preferably 0.5 to 20 mPa·s. Even if the coating liquid used has a low viscosity within the above numerical range, in this manufacturing method, as long as there is liquid between the gravure roll and the base film, the coating liquid can be applied to the base film by surface tension.

The thickness of the coating film formed in the coating process is preferably 5 to 50 nm, and more preferably 10 to 30 nm. By having the thickness of the coating film within the above numerical range, it is possible to obtain a coating film that has sufficient scratch resistance without becoming cloudy in appearance.

(Laminated film manufacturing equipment)
The laminated film manufacturing apparatus according to this embodiment (hereinafter, sometimes referred to as the present manufacturing apparatus) is configured to perform at least the coating process among the processes of the laminated film manufacturing method described above. That is, the present manufacturing apparatus is an apparatus equipped with a coating section equipped with a gravure roll that applies a coating liquid to a substrate film transported by a transport roll to form a coating film. In the present manufacturing apparatus, (i) the ratio (Vr/Vf) between the rotation speed (Vr) of the gravure roll and the transport speed (Vf) of the substrate film is set to 30 to 60, and (ii) the amount of water vapor in the coating section is adjusted to 10 to 25 g/m ^3. For example, the present manufacturing apparatus is configured to include a coating apparatus 10 shown in FIG. 1. Note that the present manufacturing apparatus appropriately cites the explanation of the above-mentioned manufacturing method.

The following examples, comparative examples, and reference examples are given, but the present invention is not limited to these.

(1) Preparation of polyamic acid solution 383 parts by weight of N,N-dimethylformamide (DMF) was added to a reaction vessel and stirred under a nitrogen atmosphere. 31.8 parts by weight of 2,2'-bis(trifluoromethyl)benzidine and 10.5 parts by weight of 3,3'-diaminodiphenylsulfone were added thereto and stirred under a nitrogen atmosphere to obtain a diamine solution. 15.9 parts by weight of p-phenylenebis(trimellitic anhydride), 37.4 parts by weight of 2,2-bis(3,4-dicarboxyphenyl)-1,1,1,3,3,3-hexafluoropropanoic anhydride, and 10.4 parts by weight of 3,3',4,4'-biphenyltetracarboxylic dianhydride were added to the diamine solution and stirred under a nitrogen atmosphere to obtain a polyamic acid solution.

(2) Imidization and extraction of polyimide resin 38.4 parts by weight of pyridine was added as an imidization catalyst to the polyamic acid solution (100 parts by weight of solid content of polyamic acid) obtained in (1) and stirred. Then, 49.5 parts by weight of acetic anhydride was added, and the mixture was stirred at 120°C for 2 hours, and then cooled to room temperature to obtain a polyimide solution. While stirring the polyimide solution, 1 L of isopropyl alcohol was dropped to precipitate the polyimide resin. Then, the filtered polyimide resin was washed three times with isopropyl alcohol, and then dried at 120°C for 12 hours to obtain a polyimide resin powder.

(3) Preparation of polyimide film The polyimide resin obtained in (2) was dissolved in methylene chloride to obtain a polyimide solution with a solid content of 10%. The polyimide solution was applied onto a substrate using a comma coater, and dried in the following order at 40° C. for 10 minutes, 80° C. for 10 minutes, 150° C. for 10 minutes, and 180° C. for 10 minutes under atmospheric pressure. The solution was then peeled off from the substrate to obtain a transparent polyimide film with a thickness of 50 μm.

(4) Preparation of hard coat composition 100 parts by weight of β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 0.12 parts by weight of magnesium chloride, 11 parts by weight of water, and 11 parts by weight of propylene glycol monomethyl ether were charged into a reaction vessel, and the mixture was stirred at 130° C. for 3 hours, and then degassed under reduced pressure at 60° C. to obtain a siloxane resin. Then, 100 parts by weight of the siloxane resin, 2 parts by weight of a propylene carbonate solution of triarylsulfonium.SbF ₆ salt, 0.2 parts by weight of a xylene/isobutanol solution of polyether-modified polydimethylsiloxane, and 100 parts by weight of propylene glycol monomethyl ether were mixed to obtain a hard coat composition.

(5) Preparation of a composition containing a perfluoroalkyl group-containing compound having an alkoxysilyl group in the molecule In the preparation, solution I: a 20% hydrofluoroether solution of a fluoroalkyl ether oligomer having a trialkoxysilyl group in the molecule (manufactured by Daikin Industries, Ltd.; OPTOOL UD509), and solution II: hydrofluoroether (manufactured by 3M; Novec7200) were used. Specifically, solution I was diluted with solution II to obtain a composition containing a perfluoroalkyl group-containing compound having an alkoxysilyl group in the molecule with a solid content concentration of 0.1% (hereinafter, sometimes referred to as coating liquid A). The viscosity of the composition was 0.6 mPa·s.

Example 1
A hard coat composition was applied to a transparent polyimide film having a thickness of 50 μm as a transparent resin film layer using a die coater so that the dry film thickness was 20 μm, and the solvent was removed by heating to 120° C. Thereafter, ultraviolet rays were irradiated using a high-pressure mercury lamp so that the accumulated light amount was 1950 mJ/cm ² , and the hard coat composition was cured to obtain a transparent resin film with a hard coat layer (hereinafter, sometimes referred to as substrate film A).

After performing a corona treatment on the surface of the hard coat layer of the base film A at a treatment density of 40 W·min/ ^m2 using a corona treatment machine, a coating step was performed in which the coating liquid A obtained in (5) was applied to the base film A. In the coating step, the coating liquid A was applied to the base film A under the following conditions using the coating device 10 shown in FIG. 1 to form a coating film with a thickness of 10 nm. (i) The ratio (Vr/Vf) of the rotation speed (Vr) of the gravure roll 3 to the conveying speed (Vf) of the base film A was set to 34. (ii) The amount of water vapor in the chamber 7 constituting the coating section was set to 17.3 g/ ^m3 . In addition, the conveying speed (Vf) of the base film A was set to 0.5 m/min.

After the coating process, the solvent in the coating film of coating solution A formed on substrate film A was removed at 130°C to obtain a hard-coated film with a fingerprint-resistant layer. In this hard-coated film, the fingerprint-resistant layer is laminated as a coating film on the hard-coat layer of substrate film A.

(Examples 2 and 3 and Comparative Examples 1 to 7)
A hard coat film with an anti-fingerprint layer was obtained in the same manner as in Example 1, except that the values of Vf and Vr were adjusted to set Vr/Vf to 1.4 to 67. The Vr/Vf set in each of Examples 2 and 3 and Comparative Examples 1 to 7 is as shown in Table 1. Furthermore, Vf was set to 0.5 m/min in Example 2, 2.0 m/min in Example 3, 0.5 m/min in Comparative Examples 1 to 4, and 2.0 m/min in Comparative Examples 5 to 7.

(Examples 4 and 5 and Comparative Examples 8 to 10)
A hard coat film with an anti-fingerprint layer was obtained in the same manner as in Example 1, except that the amount of water vapor in the chamber 7 was adjusted to 3.85 to 27.3 g/ ^m3 . The amounts of water vapor set in Examples 4 and 5 and Comparative Examples 8 to 10 are as shown in Table 1. Furthermore, Vf was set to 0.5 m/min in Examples 4 and 5 and Comparative Examples 8 to 10.

The evaluation criteria for the hard coat films with anti-fingerprint layers obtained in Examples 1 to 5 and Comparative Examples 1 to 10 are as follows:

<Appearance>
The appearance of the obtained hard coat film with the anti-fingerprint layer was evaluated by visual inspection using a light source for reflection and projection. Those that maintained the same appearance as before the anti-fingerprint layer was marked with ◯, and those that became cloudy were marked with ×.

<Scratches after abrasion resistance test>
A 6 mm diameter rubber eraser manufactured by Minoan was set on the indenter, and a reciprocating abrasion test was performed on the surface of the fingerprint-resistant layer of the hard coat film with a fingerprint-resistant layer using a reciprocating abrasion tester (Type: 30S manufactured by Shinto Scientific Co., Ltd.) under the conditions of 50 mm stroke and 1 cycle/second. The load was 500 g, and the number of times was 1500. The sample after the scratch resistance test was visually confirmed, and those with no scratches on the tested surface or scratches less than 2 mm long were marked with ○, those with scratches 2 mm or longer were marked with △, and those with scratches continuously across the entire width were marked with ×.

<Contact angle after scratch resistance test>
The water contact angle of the sample after the scratch resistance test was measured using a contact angle meter PCA-11 manufactured by Kyowa Interface Science Co., Ltd. Pure water was used for the measurement, and the droplet amount was 2 μL. A contact angle of 100° or more was evaluated as ◯, a contact angle of 90° or more but less than 100° was evaluated as △, and a contact angle of less than 90° was evaluated as ×.

The evaluation results for Examples 1 to 5 and Comparative Examples 1 to 10 are shown in Table 1.

From the evaluation results shown in Table 1, it was confirmed that when Vr/Vf is within a certain range and the amount of water vapor in the coating section (chamber 7) is within a certain range, the hard coat film having the obtained fingerprint-resistant layer has a good appearance and good scratch resistance. It is presumed that when the amount of water vapor is large as in Comparative Example 10, the silanol groups of the resin component of the coating liquid react with moisture, resulting in a poor appearance.

REFERENCE SIGNS LIST 1 Base film 2 Coating liquid 3 Gravure roll 4 Coating film 7 Chamber (coating section)
F1 Transport roll F2 Transport roll

Claims (7)

A coating process includes applying a coating liquid onto a substrate film using a gravure roll to form a coating film.
In the coating step, a ratio (Vr/Vf) of a rotation speed (Vr [unit: m/min] ) of the gravure roll to a transport speed (Vf [unit: m/min] ) of the base film is 30 to 60;
The method for producing a laminated film, wherein the amount of water vapor in the coating step is 10 to 25 g/ ^m3 . The method for manufacturing a laminated film according to claim 1, wherein the gravure roll and the substrate film transport roll rotate in different directions. The method for producing a laminated film according to claim 1 or 2, further comprising a drying step for drying the coating film formed in the coating step. The coating liquid contains a solvent and a resin soluble in the solvent,
The method for producing a laminated film according to any one of claims 1 to 3, wherein the coating liquid has a solid content concentration of 0.05 to 0.5%, the coating liquid has a viscosity of 0.1 to 100 mPa·s, and the coating film has a thickness of 10 to 50 nm. The method for manufacturing a laminated film according to any one of claims 1 to 4, wherein the coating liquid is a fluorine-based coating liquid. The method for manufacturing a laminated film according to any one of claims 1 to 5, wherein the coating film is an anti-fingerprint layer. A laminated film manufacturing apparatus including a coating unit having a gravure roll for applying a coating liquid onto a substrate film transported by a transport roll to form a coating film,
a ratio (Vr/Vf) of a rotation speed (Vr [unit: m/min] ) of the gravure roll to a transport speed (Vf [unit: m/min] ) of the base film is set to be 30 to 60;
A laminated film manufacturing apparatus, wherein the amount of water vapor in the coating section is adjusted to 10 to 25 g/ ^m3 .

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