JP3073270B2 - Substrate with hard coat film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate provided with a hard coat film having a hard coat film formed on the surface thereof for the purpose of protecting the surface of a molded product such as various plastic films. The present invention relates to a base material on which a hard coat film having a laminated structure with excellent surface hardness and improved surface hardness is formed.

[0002]

BACKGROUND OF THE INVENTION Plastic films are rich in processability and have transparency, so that protective films,
It is used as a base material for touch tablets and the like. However, the plastic film has a drawback that the surface hardness is low and it is easily damaged, and it cannot withstand long-term use as it is.

Conventionally, in order to solve the surface hardness defect, a thermosetting silicone resin, an acrylic resin, a melamine resin, an ultraviolet curable acrylic resin, or the like is applied to the surface of a plastic film and hardened by hardening. A method for forming a coat film is known. Further, a method of forming a hard coat film by adding fine particles such as silica to these resins as a filler has also been proposed.

However, in the conventional method, when the surface hardness is increased, the surface becomes brittle, and cracks due to stress strain are easily generated. On the contrary, when the flexibility is increased, the surface hardness becomes insufficient. There was a problem.
Therefore, the pencil hardness of the conventional hard coat film was limited to 4H.

The inventors of the present invention have conducted studies to solve these problems. As a result, the hard coat film was composed of at least two layers of resins having different hardnesses, and one or both of the layers contained fine particles. By doing so, it was found that the flexibility of the entire laminated film was maintained, the surface hardness was improved, and at the same time, a hard coat film having excellent impact resistance and abrasion resistance was formed. Reached.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems in the prior art, and to provide a hard coat film having excellent surface hardness and excellent impact resistance and abrasion resistance. It is an object to provide a substrate with a hard coat film having the same.

[0007]

SUMMARY OF THE INVENTION The substrate with a hard coat film according to the present invention comprises:
It comprises a substrate, a first coating formed on the surface of the substrate and a hard coat film including a second coating formed on the first coating, wherein the first coating and / or the second coating contains fine particles. And the hardness of the resin phase forming the first coating is smaller than the hardness of the resin phase forming the second coating.

In the substrate with a hard coat film according to the present invention, an elastic protective layer may be formed between the substrate and the first coating.

[0009]

DETAILED DESCRIPTION OF THE INVENTION The substrate with a hard coat film according to the present invention will be specifically described below. As shown in FIG. 1, a substrate 10 with a hard coat film according to the present invention
And a first coating 2 and a second coating 3.

Further, a substrate 1 with a hard coat film according to the present invention
0 is between the substrate 1 and the first coating 2 as shown in FIG.
An elastic protective layer 4 may be provided. As the substrate 1, any substrate can be used, but specifically,
Plastics such as polycarbonate, PET, and polyolefin are used.

In the present invention, in order to improve the surface hardness of the entire laminated film, one or both of the first coating and the second coating are formed of a resin containing fine particles. It is desirable that the fine particles in the first coating have an average particle diameter substantially equal to or larger than the thickness of the coating, and that the particles at least protrude from the surface of the coating.

The thickness of the first coating and the second coating is usually 1
Since the average particle diameter of the fine particles used for the first coating is preferably in this range or slightly larger than this. However, if the average particle size of the particles is too large compared to the film thickness, the particles will easily fall off, and problems such as reduced transparency of the coating will occur. Preferably, the particle size is approximately the same as the film thickness.

When the first coating is formed of the above-mentioned resin containing fine particles, the second coating may be formed of only the resin, but the fine particles having an average particle diameter of about 0.1 to 1.0 μm may be used. It is desirable to form with the resin containing. By doing so, the surface hardness of the laminated film is further improved, and at the same time, the surface smoothness is increased, and the wear resistance of the film is improved.

At this time, the content of the fine particles in the first coating is in the range of 1 to 15% by weight, preferably 2 to 10% by weight. If it is less than 1% by weight, the surface hardness may not be sufficient, while if it exceeds 15% by weight, the transparency of the film may be reduced. The content of the fine particles in the second coating is 0.1 to 0.8% by weight, preferably 0.2 to 0.5% by weight.
% By weight. If it is less than 0.1% by weight, the effect of adding fine particles may not be sufficient, and if it exceeds 0.8% by weight, the transparency of the film may be reduced.

In the second coating, other than the fine particles having an average particle diameter of 0.1 to 1.0 μm as described above, fine particles having a particle diameter substantially equal to or larger than the film thickness can be used.

When the second coating is formed of a resin containing fine particles having a particle diameter larger than its thickness, for example, an average particle diameter of 1 μm or more, the first coating is formed only of the resin, and is not necessarily formed of fine particles. It may not be contained. In this case, the content of the fine particles in the second coating is preferably in the range of about 2 to 10% by weight.

In this case, since the surface of the second coating becomes uneven, the surface smoothness is somewhat lost. However, this prevents glare on the surface, resulting in a so-called non-glare hard coat film.

As the resin forming the first coating and the second coating, a thermoplastic resin, a thermosetting resin, an ultraviolet curable resin, or the like is used. In the present invention, each resin is selected such that the hardness of the resin phase forming the first coating is smaller than the hardness of the resin phase forming the second coating.
Specifically, polyester resin, vinyl chloride-vinyl acetate copolymer resin, butyral resin, hard urethane resin, or the like is preferably used as the first film forming resin, and acrylic resin, silicon resin, or the like is used as the second film forming resin. Resins, melamine resins, epoxy resins, phosphazene resins and the like are preferably used.

The pencil hardness of each resin phase thus formed is preferably BH for the first coating and 2H or more for the second coating. Such a first coating and a second coating are applied by applying a coating solution obtained by dissolving or dispersing a resin and fine particles in a commonly used organic solvent onto a substrate by a normal coating method such as screen printing, drying, and further drying. It can be formed by heat curing or ultraviolet curing as appropriate.

In the present invention, an elastic protective layer 4 having a lower surface hardness than the first coating may be formed between the first coating and the substrate as described above. By providing such an elastic protective layer, stress can be further reduced,
Further, it is possible to prevent the fine particles in the first coating from biting into the base material and to improve the adhesion to the base material.

The elastic protective layer can be formed of a soft and elastic resin such as a soft urethane resin, polyvinyl chloride, a vinyl acetate (co) polymer, and a polyester resin. Further, this elastic protective layer can be formed by applying a coating liquid for forming an elastic layer, which is obtained by dissolving the above resin in an organic solvent, on a base material, similarly to the first coating.

This elastic protective layer has a pencil hardness of 3B or more.
H, preferably 2B to HB. The thickness of the elastic protective layer is desirably about 1 to 10 μm.

In the above description, the hard coat film is
Although the specific example in which the first film and the second film are formed has been described, the hard coat film may be formed of three or more films whose surface hardness is different and whose hardness decreases toward the substrate.

[0024]

The hard coat film used in the present invention has
It is composed of a laminated film of a film and a second film, and at least one of the films is formed of a resin containing fine particles. Therefore, the surface hardness of the laminated film is much higher than that of the conventional hard coat film.

Further, since the hardness of the resin phase of the first coating is smaller than the hardness of the resin phase of the second coating, the first coating has appropriate flexibility, and the first coating relieves stress distortion applied to the laminated film. Acts as a stress relaxation layer, improves impact resistance, and does not cause cracks based on brittleness unlike conventional hard coat films. As a result, the surface hardness of the hard coat film is 7H or more. It becomes possible.
Furthermore, it has excellent adhesion to the substrate.

Specific examples of such a substrate with a hard coat film include touch tablets, polarizing films for LCDs,
Furniture, marble, and the like.

[0027]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

[0028]

Example 1 Dispersant (Esodyomin T manufactured by Lion Corporation)
-13) 0.1 g and 26.4 g of a mixed solvent of isophorone-mesitylene (mixing ratio 2: 1) were mixed and stirred, and then 0.4 g of spherical silica fine particles having an average particle diameter of 6 μm was added and stirred. After mixing this with a polyester resin (manufactured by Toyobo, Byron, resin concentration 40% by weight), an antifoaming agent 6.
26 g was added to prepare a coating solution for forming a first film.

On the other hand, a phosphazene resin (Idemitsu Petrochemical U
-1000) Silica sol in which 20 g of silica fine particles having an average particle size of 0.55 μm are dispersed (SiO ₂ concentration: 20% by weight)
0.2 g was added and mixed, and 0.2 g of a leveling agent (manufactured by Kusumoto Kasei Co., Ltd., Dispalon # 1610) and 0.1 g of an anti-scratch agent (SH-94PA manufactured by Toray Silicone) were added and stirred, followed by application for forming a second coating film. A liquid was prepared.

The coating liquid for forming the first film was screen-printed on a surface of a PET film substrate having a thickness of 188 μm to a size of 10 cm square with a 250 mesh polyester screen film, and heated at 120 ° C. for 10 minutes. A first coating having a thickness of 4 μm was formed.

On this coating film, a coating liquid for forming a second coating film was applied to a 380 mesh polyester screen film for 10 cm.
Screen printing was performed to the size of the corners, and the screen was cured with an ultraviolet irradiation device to form a second coating having a thickness of 4 μm, thereby forming a hard coat film.

[0032]

Example 2 In Example 1, 0.2 g of particles having an average particle size of 6 μm and 0.1 g of particles having an average particle size of 2.4 μm were used instead of the spherical silica fine particles of the coating liquid for forming the first film. And using 0.05 g of the dispersant,
A coating solution for forming a first film was prepared in the same manner as in Example 1.

The coating liquid for forming the first coating and the coating liquid for forming the second coating used in Example 1 were used in the same PET as in Example 1.
It was applied to a film substrate in the same manner as in Example 1 to form a hard coat film.

[0034]

Embodiment 3 A thermosetting silicone resin (manufactured by Daihachi Chemical, S
i-coat 2) The same silica sol as in Example 1 was added to 20 g.
2 g was added and stirred, and then 0.1 g of an antifoaming agent (Kusumoto Kasei Co., Ltd., specially modified silicon-based disparon # 230) was added and stirred to prepare a second coating film forming coating solution.

On the first film formed in Example 2, a second
The coating liquid for forming a film is screen-printed on a 180-mesh polyester screen film to a size of 10 cm square,
It was dried by heating at 50 ° C. for 5 minutes to form a second coating having a thickness of 6 μm, thereby forming a hard coat film.

[0036]

Example 4 0.1 g of an antifoaming agent (manufactured by West Germany, Contra-Air Poly) was added to 20 g of a vinyl chloride-vinyl acetate resin (manufactured by Sekisui Chemical, Eslek A (resin concentration: 30%)) to form an elastic protective layer. Coating solution.

This coating solution was applied to the same PET substrate as in Example 1 using a 250-mesh polyester screen film.
It was screen-printed to a size of 0 cm square and dried by heating at 120 ° C. for 10 minutes to form an elastic protective layer having a thickness of 3 μm.

On the elastic protective layer, the coating liquid for forming the first film of Example 2 was screen-printed to a size of 10 cm square using a 250-mesh polyester screen film.
The resultant was dried by heating at 10 ° C. for 10 minutes to form a first coating having a thickness of 4 μm.

Finally, the coating solution for forming the second film of Example 2 was applied to the first film using a 380 mesh polyester screen film.
A 10 cm square screen was printed on the film and cured by an ultraviolet irradiation device, and then a second film having a thickness of 4 μm was formed to form a hard coat film.

[0040]

Example 5 Dispersant (Esodyomin T manufactured by Lion Corporation)
-13) 0.05 g and 4.0 g of mesitylene are mixed and stirred, and 40 g of a polyvinyl chloride-vinyl acetate copolymer resin (manufactured by Sekisui Chemical Co., Ltd., Eslek A) is added thereto, and then 0.4 g of an antifoaming agent is added and mixed. Thus, a coating solution for forming a first film was prepared.

On the other hand, a phosphazene resin (manufactured by Idemitsu Chemical Co., U.S.A.)
1.-1000) 40 g of silica fine particles having an average particle diameter of about 6 μm (Silica Microbead, manufactured by Kako Kagaku Co., Ltd.)
0 g was added and mixed. Next, 0.8 g of a leveling agent (manufactured by Toray Dow Corning, DC-11PA) and a defoaming agent of 0.1 g were used.
4 g was added to prepare a coating solution for forming a second film.

The coating liquid for forming the first film was prepared using the same P as in Example 1.
It was applied to an ET film substrate in the same manner as in Example 1 to form a first coating having a thickness of 4 μm. On top of this coating, a second
The coating liquid for forming a film was applied in the same manner as in Example 1 to form a second film having a thickness of 4 μm, and a hard coat film was formed.

The following evaluation was performed on the obtained hard coat film. (A) Total light transmittance: measured using a haze computer HGM-2DP manufactured by Suga Test Instruments. (B) Haze: Haze computer HG manufactured by Suga Test Machine
Measured using M-2DP. (C) Taper abrasion test: After two abrasion wheels 250 g were moved on the cured film for 250 cycles by a taper abrasion tester, the haze difference was determined. (D) Steel wool test: steel wool # 0000
After 50 times of sieving under a load of 1 kg, the haze difference was determined. (E) Sand fall test: After dropping 1000 g of # 80 coarse particles on a cured film, the haze difference was determined. (F) Pencil hardness: Evaluated with a pencil hardness tester according to JIS K 5400. (G) Glossiness: Digital variable angle glossmeter UG manufactured by Suga Test Instruments
The measurement was performed at an incident angle of 60 ° and a light receiving angle of 60 ° by V-5D.

The results are shown in Table 1.

[0045]

[Comparative Example] Toray Top 188L-B2TO manufactured by Toray (188 μm having a single-layer inorganic particle-containing hard coat film formed thereon)
(Thick PET film) was evaluated in the same manner as in the example.

The results are shown in Table 1.

[0047]

[Table 1]

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a substrate with a hard coat film of the present invention.

FIG. 2 is a cross-sectional view of the substrate with a hard coat film of the present invention.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Tsuguo Koyanagi 2-6-2 Otemachi, Chiyoda-ku, Tokyo Inside the Catalyst Chemical Industry Co., Ltd. (56) References JP-A-3-130199 (JP, A) JP-A-2-26942 (JP, A) JP-A-4-93245 (JP, A) JP-A-62-170331 (JP, A) JP-A-62-170330 (JP, A) (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B32B 1/00-35/00 C08J 7/04

Claims (2)

(57) [Claims] 1. A first coating and / or a second coating comprising a substrate and a hard coat film including a first coating formed on the surface of the substrate and a second coating formed on the first coating. (1) A substrate with a hard coat film, wherein the substrate is formed from a resin containing fine particles, and a hardness of a resin phase forming a first coating is smaller than a hardness of a resin phase forming a second coating. 2. The substrate with a hard coat film according to claim 1, wherein an elastic protective layer is formed between the substrate and the first coating.