JP5495913B2 - Manufacturing method of anti-glare filter - Google Patents

Description

  The present invention relates to a method for producing an antiglare filter.

  The surface of image display devices such as liquid crystal display devices has anti-glare properties by a method of laminating anti-glare filters having fine irregularities on the surface of the image display device for the purpose of preventing reflection of external light. Often granted.

Anti-glare treatment that imparts fine irregularities on the surface of the substrate is called non-glare treatment or anti-glare treatment. As an example of the anti-glare treatment method, the surface between a mold having a minute irregular shape and a synthetic resin substrate is used. By polymerizing and curing the scratch-resistant film-forming raw material in a state where the scratch-resistant film-forming raw material is spread, and then peeling the laminate in which the scratch-resistant film is laminated on the surface of the synthetic resin substrate from the mold There has been proposed a method of imparting a minute uneven shape to the surface of the laminate. (For example, Patent Document 1 and Patent Document 2)
However, in these production methods, when the scratch-resistant film-forming raw material is polymerized and cured, a minute sink defect is generated in the obtained scratch-resistant film, and the commercial value is deteriorated or the yield is deteriorated. There was a problem.

  On the other hand, in order to prevent sink defects, a method of controlling the mold temperature in injection molding has been disclosed (Patent Document 3). However, in the case of producing a laminate having a laminated film by injection molding, it is necessary to separately produce an abrasion-resistant film and transfer it in a mold, which is disadvantageous in terms of cost. In addition, since the molding temperature is relatively high, it is difficult to maintain a fine uneven shape of the film.

JP 61-76328 A JP-A 64-46702 JP 2006-110905 A

  The present invention provides a method for producing an anti-glare filter having anti-glare and scratch resistance in an anti-glare filter having a scratch-resistant film laminated on the surface of a synthetic resin substrate, with few sink defects in the scratch-resistant film. The task is to do.

In the present invention, the scratch-resistant film forming raw material is polymerized and cured after spreading the scratch-resistant film forming raw material between a mold having an uneven shape on the surface (hereinafter referred to as “the present mold”) and a synthetic resin substrate. Anti-glare film that forms a scratch-resistant film and then peels off the laminate (hereinafter referred to as “the present laminate”) in which a scratch-resistant film having a concavo-convex shape is laminated on the surface of the synthetic resin base material. An anti-glare filter (hereinafter referred to as an anti-glare filter) having a mold temperature and a synthetic resin substrate temperature when the scratch-resistant film forming raw material is spread between the mold and the synthetic resin substrate. , “This antiglare filter”).
<Condition of mold temperature and synthetic resin substrate temperature>
Mold temperature: 40 ° C. or less 7 ° C. ≧ (synthetic resin substrate temperature−mold temperature) ≧ 0 ° C.

  According to the present invention, an anti-glare filter having anti-glare and scratch resistance can be obtained with few sink defects in the scratch-resistant film. Therefore, the anti-glare filter obtained by the present invention is used for a front panel of a liquid crystal screen, a meter cover, etc. It can be suitably used for products that require anti-glare and scratch resistance.

This mold

The present mold used in the present invention has an uneven shape on the surface.

  In the present invention, the uneven shape formed on the surface of the mold is a shape adjusted so that the surface roughness of the antiglare filter is 0.05 to 0.3 μm in terms of the center line average roughness (Ra). It is preferable that

  The anti-glare property of the anti-glare filter is good by making the irregular shape of the mold into a shape adjusted so that the surface roughness of the anti-glare filter is 0.05 μm or more in terms of the center line average roughness (Ra). Tend to be. In addition, by making the irregular shape of the mold into a shape adjusted so that the surface roughness of the anti-glare filter is 0.3 μm or less in terms of the center line average roughness (Ra), light transmission of the anti-glare filter is achieved. The rate tends to be good.

  Examples of the material constituting the mold include metals such as glass, stainless steel, and aluminum, and those metals subjected to surface treatment such as nickel plating, hard chrome plating, and synthetic resin.

  Among these materials, glass and surface-treated metal are preferable in terms of scratch resistance and durability.

  Examples of the shape of the mold include a plate shape and a roll shape.

As a method for imparting a concavo-convex shape to the surface of the mold, for example, a method by etching treatment may be mentioned. As a specific example of the etching treatment when glass is used as the mold, there is a treatment in which the glass surface is brought into contact with an aqueous solution containing hydrogen fluoride.

Synthetic resin base material

As the synthetic resin substrate used in the present invention, a transparent resin having rigidity at room temperature and excellent in transparency is preferable in terms of obtaining an antiglare filter used for applications such as a front plate of an image display device.

  Specific examples of the synthetic resin substrate include polymethyl methacrylate, a copolymer having methyl methacrylate as a main structural unit, polystyrene, a styrene-methyl methacrylate copolymer, and a polycarbonate.

In the present invention, the synthetic resin substrate is preferably a plate-like product, and the thickness is usually 0.2 to 20 mm.

Scratch-resistant film forming raw material

Examples of the scratch-resistant film-forming raw material used in the present invention include those containing a polymerizable compound having two or more (meth) acryloyloxy groups in the molecule (hereinafter referred to as “the present polymerizable compound”). Can be mentioned.

  Specific examples of the polymerizable compound include esterified products obtained from 1 mol of polyhydric alcohol and 2 mol or more of (meth) acrylic acid or a derivative thereof; and polyhydric alcohol and polyvalent carboxylic acid or an anhydride thereof. Examples include esterified products obtained from (meth) acrylic acid or its derivatives.

  In the present invention, “(meth) acryl” represents at least one selected from “acryl” and “methacryl”.

  Examples of esterified products obtained from 1 mol of polyhydric alcohol and 2 mol or more of (meth) acrylic acid or derivatives thereof include, for example, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, and tetraethylene glycol di (Meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, Trimethylolethane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, glycerin tri (meth) acrylate, dipentaerythritol penta (meth) acrylate and Dipentaerythritol hexa (meth) acrylate.

  Examples of esterified products obtained from polyhydric alcohols and polyhydric carboxylic acids or anhydrides thereof and (meth) acrylic acid or derivatives thereof include, for example, malonic acid, succinic acid, adipic acid, glutaric acid, sebacic acid, fumaric acid, Esters obtained from polyvalent carboxylic acids such as itaconic acid and maleic anhydride, or anhydrides thereof, polyhydric alcohols such as trimethylolethane, trimethylolpropane, glycerin, pentaerythritol, and (meth) acrylic acid or derivatives thereof A compound.

  In the present invention, a thermal polymerization initiator or a photopolymerization initiator can be added to the scratch-resistant film forming raw material as necessary.

  Examples of the photopolymerization initiator include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, acetoin, butyroin, toluoin, benzyl, benzophenone, p-methoxybenzophenone, 2,2-diethoxyacetophenone, α, α-dimethoxy-α-phenylacetophenone, methylphenylglyoxylate, ethylphenylglyoxylate, 4,4′-bis (dimethylamino) benzophenone, 2-hydroxy-2-methyl-1-phenylpropane-1- Carbonyl compounds such as ON; sulfur compounds such as tetramethylthiuram monosulfide and tetramethylthiuram disulfide; 2,4,6-trimethylbenzoyldiphenylphosphine oxide Phosphorus-based compounds such as benzo dichloride ethoxy phosphine oxide.

  Examples of the light source used for photopolymerization include ultraviolet X-rays and electron beams.

  The addition amount of the photopolymerization initiator is preferably 0.1 parts by mass or more with respect to 100 parts by mass of the present polymerizable compound from the viewpoint of curability by ultraviolet rays, and can maintain a good color tone of the scratch-resistant film described later. The point is preferably 10 parts by mass or less.

  In the present invention, the scratch-resistant film-forming raw material is spread between the mold and the synthetic resin substrate.

  The mold temperature when the scratch-resistant film forming raw material is spread between the present mold and the synthetic resin substrate is set to 40 ° C. or lower.

  By setting the mold temperature to 40 ° C. or lower, preferably 37 ° C. or lower, the viscosity of the scratch-resistant film-forming raw material does not become too low, and the scratch-resistant film-forming raw material can be stably spread. Insufficient thickness of the scratch-resistant film in the filter can be suppressed. The mold temperature is 30 ° C. or higher, preferably 33 ° C. or higher. By setting the mold temperature to 30 ° C. or higher, the cooling time of the mold can be shortened after peeling off the scratch-resistant film after polymerization curing of the scratch-resistant film forming raw material when the mold is repeatedly used. Therefore, it is possible to suppress a decrease in productivity of the antiglare filter.

  In the present invention, the sink defect generated in the scratch-resistant film refers to the scratch-resistant film forming raw material when the scratch-resistant film forming raw material is spread between the mold and the synthetic resin substrate. It refers to a portion that has been withered and formed in the scratch-resistant film after polymerization and curing due to the mixing of bubbles.

  As a method for spreading the scratch-resistant film forming raw material between the mold and the synthetic resin base material, for example, on the surface having the uneven shape of the mold in which the temperature of the scratch-resistant film forming raw material is adjusted to 40 ° C. or lower. A synthetic resin base material, which is cast and is adjusted to a temperature equal to or higher than the mold temperature within a range of 7 ° C. or more, is laminated thereon, and between the main mold and the synthetic resin base material by a press roll from above. For example, a method of spreading so that no bubbles remain on the surface.

  As described above, the temperature of the synthetic resin base material when the scratch-resistant film forming raw material is spread between the present mold and the synthetic resin base material is set to be the same as the mold temperature or higher within the range of 7 ° C. or lower than the mold temperature. The

  When the synthetic resin substrate temperature is lower than the mold temperature, the surface side of the surface of the synthetic resin substrate that is in contact with the scratch-resistant film forming raw material expands due to the heat of the mold, and the synthetic resin substrate Warps in a concave shape, and floating occurs on the four sides of the synthetic resin base material. When floating occurs on the four sides of the synthetic resin base material, bubbles are mixed into the scratch-resistant film forming raw material spread from the peripheral portion of the spread scratch-resistant film forming raw material, resulting in sink marks, Absent. When the synthetic resin substrate temperature is higher than the mold temperature by more than 7 ° C., the surface side of the surface of the synthetic resin substrate that is in contact with the scratch-resistant film forming raw material is cooled by the mold, and the synthetic resin substrate The convex warpage of the material becomes excessive, and as a result, the film thickness becomes uneven, which is not preferable. Furthermore, when the synthetic resin substrate temperature is higher than the mold temperature by 7 ° C., the viscosity of the scratch-resistant film forming raw material becomes too low, and it becomes difficult to stably spread the scratch-resistant film forming raw material. It is not preferable.

  Examples of a method for adjusting the temperature of the synthetic resin base material include a temperature adjustment method using a normal hot air circulation heating furnace and an infrared heater.

  In the present invention, examples of the polymerization and curing method of the scratch-resistant film-forming raw material include a thermal polymerization method and a photopolymerization method. However, in terms of relatively simple equipment and high productivity, ultraviolet irradiation is used. Photopolymerization is preferred.

As a light irradiation method when performing photopolymerization of the scratch-resistant film forming raw material, a method of irradiating active energy rays such as ultraviolet rays through a synthetic resin substrate is generally effective. Further, when using a synthetic resin substrate that is impermeable to active energy rays, a method of using glass as a mold and irradiating ultraviolet rays through the glass is effective.

Scratch resistant film

In the present invention, the scratch-resistant film is obtained by spreading a scratch-resistant film-forming raw material between the mold and the synthetic resin substrate and then polymerizing and curing it.

The thickness of the scratch-resistant film is preferably 5 to 50 μm, more preferably 7 to 20 μm. When the thickness of the scratch-resistant film is 5 μm or more, the surface hardness and the scratch resistance of the scratch-resistant film tend to be good. Moreover, when the thickness of the scratch-resistant film is 50 μm or less, the antiglare filter tends not to be brittle.

This laminate

In the present invention, the laminate and the mold in which the scratch-resistant film having a concavo-convex shape is laminated on the surface of the synthetic resin substrate are in contact with the surface of the scratch-resistant film of the laminate and the mold. It is formed in a state.

Anti-glare filter

In the present invention, the antiglare filter is obtained by peeling the laminate from the mold.

  Further, the shape of the surface of the mold is transferred to the surface of the scratch-resistant film of the antiglare filter to give an uneven shape. The surface roughness of the antiglare filter is preferably 0.05 to 0.3 μm in centerline average roughness (Ra).

Hereinafter, the present invention will be specifically described by way of examples. The antiglare filter was evaluated by the following method. In the following, “part” means “part by mass”.
(1) Surface roughness Centerline average roughness of the surface of the anti-glare film of the antiglare filter using a nanoscale hybrid microscope (manufactured by Keyence Corporation, product name: VN-8000) according to JIS B 0601 ( Ra) was measured and the surface roughness was evaluated.
(2) Scratch resistance A rubbing tester manufactured by Taihei Rika Kogyo Co., Ltd. was used. A 1-inch diameter circular pad with steel wool (manufactured by Nippon Steel Wool Co., Ltd., trade name: Bonster # 0000) is pressed against the surface of the anti-glare film of the anti-glare filter and a load is applied to the pad. The limit load, which is the lowest load at which scratching starts on the scratch-resistant film-forming surface of the antiglare filter when it was subjected to 10 reciprocal scratches, was measured. The larger the limit load, the better the scratch resistance.
(3) Sink defect Using a fluorescent lamp (manufactured by Hitachi, Ltd., 40W type fluorescent lamp, three-wavelength type, daylight color) as the light source, allowing the light of the fluorescent lamp to pass through the anti-glare filter, and visually checking the scattering state of the transmitted light By observing, the presence or absence of sink marks in the anti-glare filter was judged according to the following criteria.
○: Light is uniformly scattered and no sink defect is observed.
X: A sink defect which is a portion where light is transmitted without being scattered is recognized.
[Example 1]
40 parts of a condensed ester of trimethylolethane, acrylic acid and succinic anhydride (trade name: TAS manufactured by Osaka Organic Chemical Industry Co., Ltd.), 30 parts of dipentaerythritol hexaacrylate, 30 parts of 1,6 hexanediol diacrylate, and A scratch-resistant film forming raw material in which 2 parts of 2,4,6-trimethylbenzoyldiphenylphosphine oxide was mixed was prepared.

  A glass plate having an area of about 630 mm × 530 mm and a thickness of 3 mm and having fine irregularities formed on the surface (manufactured by Sanwa Frost Kogyo Co., Ltd., trade name: frost processing 65% (soda glass single-sided frost processing, surface gloss) 65%)) was used as a mold, and the above-mentioned scratch-resistant film-forming raw material was spread on the surface of the mold whose mold temperature (Tm) was adjusted to 35 ° C.

  Subsequently, a 1 mm thick colorless and transparent methacrylic resin plate (manufactured by Mitsubishi Rayon Co., Ltd., trade name: synthetic resin substrate temperature (Tb) set to 35 ° C. on the spread scratch-resistant film forming raw material. Acrylite L # 001) is laminated and pressed from above the methacrylic resin plate with a roller so that no air bubbles remain between the methacrylic resin plate and the glass plate, and the thickness of the scratch-resistant film forming raw material is about 10 μm. A laminate was obtained.

  First, the above laminate was irradiated for 10 seconds from a glass plate side from a height of 12 cm using two metal halide lamps (trade name: UVL-12K1M3-N, manufactured by Ushio Electric Co., Ltd.) arranged at intervals of 400 mm. Then, a scratch-resistant film having a thickness of 10 μm was formed.

Next, the laminate of the methacrylic resin plate on which the scratch-resistant film is laminated is peeled off from the glass plate, and the laminate is irradiated with a metal halide lamp from the surface side of the scratch-resistant film under the same conditions as the above irradiation conditions. After the film was cured, an antiglare filter was obtained. When the surface roughness of the antiglare filter on which the scratch resistant film was formed was evaluated, the Ra was 0.15 μm, and the limit load at the time of scratch resistance evaluation was 1,000 g. Further, when the appearance of the anti-glare filter was visually observed, no sink defect was observed. The obtained results are shown in Table 1.
[Example 2 and Comparative Examples 1 to 6]
An antiglare filter was obtained in the same manner as in Example 1 except that the mold temperature and the synthetic resin substrate temperature were set to the temperatures shown in Table 1. The evaluation results of the obtained antiglare filter are shown in Table 1.
[Example 3]
Example 1 except that a glass plate having a surface glossiness of 110% (manufactured by Sanwa Frost Kogyo Co., Ltd., trade name: 110% frosting (soda glass single-sided frosting, surface glossiness 110%)) is used as a mold. In the same manner as above, an antiglare filter was obtained. The evaluation results of the obtained antiglare filter are shown in Table 1.
[Example 4]
Example 1 except that a glass plate having a surface gloss of 30% (manufactured by Sanwa Frost Kogyo Co., Ltd., trade name: frost processing 30% (soda glass single-sided frost processing, surface gloss 30%)) is used as a mold. In the same manner as above, an antiglare filter was obtained. The evaluation results of the obtained antiglare filter are shown in Table 1.

  As is clear from the results of Examples 1 to 5 in Table 1, the antiglare property and scratch resistance can be obtained by setting the mold temperature to 40 ° C. or less and (synthetic resin substrate temperature−mold temperature) to 0 to 5 ° C. An anti-glare filter having excellent properties and few sink marks was obtained. On the other hand, in Comparative Examples 1 to 3, the mold temperature is 40 ° C. or less, but (synthetic resin substrate temperature−mold temperature) is less than 0 ° C. or exceeds 5 ° C. Or the scratch resistance was low. In Comparative Example 4, since the mold temperature exceeded 40 ° C. and (synthetic resin substrate temperature−mold temperature) was also less than 0 ° C., the sink defect was low. In Comparative Example 6, (synthetic resin substrate temperature−mold temperature) was in the range of 0 to 5 ° C., but the scratch resistance was low because the mold temperature exceeded 40 ° C.

Claims (2)

Between a mold having a concavo-convex shape on the surface and a synthetic resin substrate selected from polymethyl methacrylate, a copolymer having methyl methacrylate as a main structural unit, polystyrene, styrene-methyl methacrylate copolymer and polycarbonate. , After spreading a scratch-resistant film-forming material containing a polymerizable compound having two or more (meth) acryloyloxy groups in the molecule , the scratch-resistant film-forming material is polymerized and cured to form a scratch-resistant film. A method for producing an antiglare filter that is formed and then peels off a laminate in which a scratch-resistant film having a concavo-convex shape is laminated on the surface of a synthetic resin substrate, and is synthesized with a mold having a concavo-convex shape on the surface A method for producing an antiglare filter, wherein a mold temperature and a synthetic resin substrate temperature when the scratch-resistant film forming raw material is spread between the resin substrate and the resin substrate are as follows.
<Condition of mold temperature and synthetic resin substrate temperature>
Mold temperature: 30 ° C. or more and 40 ° C. or less 7 ° C. ≧ (synthetic resin substrate temperature−mold temperature) ≧ 0 ° C.   2. The mold according to claim 1, wherein the mold has a surface provided with an uneven shape such that the surface roughness of the obtained antiglare filter is 0.05 to 0.3 μm in terms of centerline average roughness (Ra). Manufacturing method of anti-glare filter.