JP2023115418A - Antistatic antiglare film - Google Patents

Abstract

To provide an antiglare hard coat film that has antistatic properties and, even when used in a high-precision display, causes little flicker and offers excellent visibility.SOLUTION: An antistatic antiglare film includes a cured layer of a photocurable resin composition which contains a polyfunctional urethane methacrylate with an acryl equivalent of 300-30,000 g/eq, conductive inorganic fine particles, fine particles with an average particle size of 0.1-4 μm, and a photopolymerization initiator, wherein the content of the fine particles is 0.5-13 pts.wt. relative to 100 pts.wt. of the polyfunctional urethane methacrylate.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to an antiglare film having excellent antistatic properties, high definition and no feeling of flickering.

In recent years, touch panels, which combine a display device and an input means, have been used in a wide range of fields. Representative examples of such touch panels include car navigation systems and smartphones, which have fine irregularities formed on their surfaces in order to improve the visibility of images. An anti-glare film is used to scatter reflected light such as fluorescent lights and sunlight, making glare less noticeable.

As an antiglare film that can be used for such applications, the applicant has previously cured a resin composition containing a polyfunctional (meth)acrylate, a fluorine-modified resin with a specific structure, translucent fine particles, and two or more leveling agents. have invented an anti-glare film that has been made with a This invention is excellent in that the visibility is very good because it is difficult for fingerprints to adhere and external light is difficult to diffusely reflect. However, in the case of high-definition displays with a large increase in the number of pixels compared to conventional displays, flickering (scintillation phenomenon) caused by irregular reflection of image light becomes noticeable when conventional anti-glare films are used. A problem has become apparent that the visibility of the image is significantly impaired.

In addition to improving visibility, static electricity generated on the surface of the display deteriorates dust resistance and makes it easier for dust to adhere. There is still room for improvement in order to realize a hard coat film that has both high definition, good visibility without flickering, and antistatic performance.

Japanese Patent No. 5602999

An object of the present invention is to provide an antiglare hard-coated film that has antistatic properties and exhibits very good visibility with little flicker even when used in high-definition displays.

In order to solve the above-mentioned problems, the invention of claim 1 of the present application comprises polyfunctional urethane (meth)acrylate (A), conductive inorganic fine particles (B), and fine particles having an average particle diameter of 0.1 to 4 μm ( C) (excluding (B)) and a photopolymerization initiator (D), wherein the acrylic equivalent of (A) is 300 to 30,000 g / eq, and the amount of (C) is Provided is an antistatic antiglare film characterized by having a cured layer of a photocurable resin composition in an amount of 0.5 to 13 parts by weight per 100 parts by weight of (A).

The invention of claim 2 provides the antistatic antiglare film of claim 1, wherein the (B) is antimony-doped tin oxide.

The invention according to claim 3 provides the antistatic antiglare film according to any one of claims 1 and 2, wherein the average particle size of (B) is 10 to 300 nm.

The invention according to claim 4 provides the antistatic antiglare film according to any one of claims 1 to 3, wherein (A) has a weight average molecular weight of 1,500 to 300,000.

The anti-glare film of the present invention has excellent antistatic performance, so it does not adhere to dust caused by static electricity, and it can suppress reflection of external light and flickering of images, and has good visibility. It is useful as a hard coat film (hereinafter referred to as HC film) used in fine displays.

The present invention will be described in detail.

The antistatic antiglare film of the present invention comprises polyfunctional urethane (meth)acrylate (A), conductive inorganic fine particles (B), fine particles having a specified average particle size (C), and a photopolymerization initiator ( It has a cured layer of a photocurable resin composition (hereinafter referred to as the present composition) containing D). In this specification, (meth)acrylate includes both acrylate and methacrylate, and (meth)acryloyl includes both acryloyl and methacryloyl.

The polyfunctional urethane (meth)acrylate (A) used in this composition has excellent scratch resistance due to the cohesion of hydrogen bonds derived from urethane bonds, and is the main component of the hard coat film. It also serves as a binder for dispersing (B) and (C). For example, it can be obtained by reacting a urethane prepolymer obtained by reacting a polyol with an excessive amount of polyisocyanate with a (meth)acrylate having a hydroxyl group, or by reacting a polyisocyanate with a (meth)acrylate having a hydroxyl group. The number of functional groups is preferably 4 or more, more preferably 6 or more, and particularly preferably 8 or more.

The acrylic equivalent of (A) is 300 to 30,000 g/eq, preferably 350 to 10,000 g/eq, and more preferably 400 to 8,000 g/eq. If it is less than 300 g/eq, the antistatic performance and visibility tend to deteriorate. . In this specification, the acrylic equivalent is a value obtained by dividing the weight average molecular weight (hereinafter referred to as Mw) by the average number of (meth)acryloyl groups.

The Mw of (A) is preferably 1,500 to 300,000, more preferably 2,000 to 200,000, and particularly preferably 3,000 to 100,000. By making it 1,500 or more, sufficient antistatic performance and visibility can be secured, and by making it 300,000 or less, it is possible to easily adjust the viscosity to suit workability. The Mw was calculated by measuring the molecular weight in terms of standard polystyrene by gel permeation chromatography using a column using a styrene-divinylbenzene-based packing material and using a tetrahydrofuran eluent.

The content of (A) is preferably 30 to 80% by weight, more preferably 35 to 75% by weight, particularly preferably 45 to 65% by weight, based on the total solid content. A content of 30% by weight or more can ensure sufficient optical properties and abrasion resistance, and a content of 80% by weight or less can ensure sufficient antistatic performance and visibility.

The conductive inorganic fine particles (B) used in the present composition are blended for the purpose of imparting antistatic performance to the cured film, improving the hardness so as to have sufficient scratch resistance, and further increasing the haze. For example, antimony-doped tin oxide (hereinafter referred to as ATO), tin-doped indium oxide, fluorine-doped tin oxide, phosphorus-doped tin oxide, indium-doped zinc oxide, aluminum-doped zinc oxide, zinc antimonate, etc., may be used alone or in combination of two or more. can be used Among these, ATO is preferable because it has excellent light transmittance and its conductive performance is not easily influenced by atmosphere such as humidity and temperature.

The average particle size of (B) is preferably 10 to 300 nm, more preferably 30 to 200 nm, particularly preferably 50 to 150 nm. A thickness of 10 nm or more can ensure sufficient scratch resistance, and a thickness of 300 nm or less can ensure sufficient optical properties without impairing transparency. The average particle size below is the median size (d=50) measured by the laser diffraction/scattering method according to JISZ8825-1.

The blending amount of (B) is preferably 25 to 160 parts by weight, more preferably 30 to 150 parts by weight, and particularly preferably 40 to 100 parts by weight, per 100 parts by weight of (A). Also, the total solid content is preferably 18 to 65% by weight, more preferably 20 to 60% by weight, and particularly preferably 25 to 40% by weight. When the amount is 25 parts by weight or more, sufficient antistatic properties can be secured, and when the amount is 160 parts by weight or less, sufficient optical properties can be secured without impairing transparency.

The fine particles used in the present composition (C) are formulated for the purpose of forming unevenness on the surface of the cured film and scattering light in the coating layer to impart antiglare properties. Microparticles can be used. (C) has an average particle size of 0.1 to 4 μm, preferably 0.2 to 3 μm, more preferably 0.3 to 2.5 μm. If the thickness is less than 0.1 μm, the light scattering effect tends to be insufficient and the anti-glare property tends to be insufficient. tend to be less sexual.

Examples of the organic fine particles used in (C) include acrylic resins, styrene resins, silicone resins, polycarbonate resin powders, acrylic-styrene resins, benzoguanamine resins, melamine resins, polyolefin resins, and polyesters. system resins, polyamide system resins, polyimide system resins, polyethylene fluoride resins, etc., and may be used alone or in combination of two or more. Among these, acrylic resins are preferred because of their good dispersibility in (A) and excellent availability.

Examples of the inorganic fine particles used in (C) include silica, titanium oxide, aluminum oxide, calcium carbonate, barium sulfate, talc, kaolin, calcium sulfate, etc., and may be used alone or in combination of two or more. can. Among these, silica is preferable because it has excellent translucency and has a refractive index relatively close to that of (A). When silica is used, surface-treated hydrophobic silica is preferred in order to improve dispersibility in component (A).

The content of (C) is 0.5 to 13 parts by weight, preferably 0.8 to 10 parts by weight, more preferably 1 to 8 parts by weight, per 100 parts by weight of (A). It is preferably 0.3 to 10% by weight, more preferably 0.5 to 8% by weight, particularly preferably 1 to 6% by weight, based on the total solid content. If the amount is less than 0.5 parts by weight, the required anti-glare property may not be ensured, and if it exceeds 13 parts by weight, sufficient visibility may not be ensured.

The photopolymerization initiator (D) used in the present composition generates radicals upon irradiation with ultraviolet rays, electron beams, etc., and the radicals trigger the polymerization reaction. A general-purpose photopolymerization initiator such as a system can be used. Curability can be imparted over a wide wavelength range from the ultraviolet region to the visible light region by arbitrarily selecting the light absorption wavelength of the polymerization initiator. Specifically, 2,2-dimethoxy-1,2-diphenylethan-1-one is a benzyl ketal system, and 1-hydroxy-cyclohexyl-phenyl-ketone and 1-[4-(2- hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one is 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropane-1 as α-aminoacetophenone -ones include acylphosphine oxides such as 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, either singly or in combination of two or more can be used in combination. Among these, it is preferable to contain an α-hydroxyacetophenone type that is resistant to yellowing.

The mixing ratio of (D) is preferably 0.5 to 10 parts by weight, more preferably 3 to 8 parts by weight, per 100 parts by weight of the photocurable resin component. When the amount is 0.5 parts by weight or more, sufficient curability can be ensured, and when the amount is 10 parts by weight or less, excessive addition can be avoided, and yellowing of the coating film and deterioration of storage stability can be prevented.

Desirably, the composition further contains a leveling agent having antifouling properties. Examples include fluorine-based, silicone-based, and fluorine-silicone-based compounds. In particular, if it has a reactive functional group that undergoes a polymerization reaction with (A), it will not be removed from the cured film over time, and the effect can be maintained for a long period of time, which is preferable. Commercially available products include X-71-1203M (product name: Shin-Etsu Chemical Co., Ltd., fluorine-silicone compound).

The blending amount of the leveling agent is preferably 0.1 to 5.0 parts by weight, more preferably 0.2 to 3.0 parts by weight, per 100 parts by weight of the photocurable resin component. When the amount is 0.1 part by weight or more, sufficient leveling properties can be obtained to ensure a good appearance. .

The present composition may also contain an acrylic monomer as a reactive diluent. Examples include aliphatic (meth)acrylates, alicyclic (meth)acrylates, aromatic (meth)acrylates, ether skeleton (meth)acrylates, hydroxyl group-containing (meth)acrylates, amide group-containing (meth)acrylates, and acrylamides. , can be used alone or in combination of two or more. Although the number of functional groups is not particularly limited, it is preferably bifunctional or less in terms of reducing curing shrinkage.

The amount of the reactive diluent compounded is preferably 100 parts by weight or less, more preferably 80 parts by weight or less, and particularly preferably 60 parts by weight or less per 100 parts by weight of (A). By making it 100 parts by weight or less, it is possible to ensure sufficiently high definition.

Further, the present composition may contain antifouling agents, water repellents, ultraviolet absorbers, antioxidants, coloring agents, defoaming agents, thickeners, anti-settling agents, anti-fogging agents, slip agents, and antibacterial agents, if necessary. Agents and the like may be added.

The present composition is diluted with a solvent to a solid content of 10 to 70% in order to improve the coatability onto an organic plastic film. Examples of the solvent include alcohol solvents such as ethanol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol and diacetone alcohol, acetone, methyl ethyl ketone (hereinafter referred to as MEK), methyl isobutyl ketone (hereinafter referred to as MIBK), cyclohexanone and the like. ketone solvents, ester solvents such as methyl acetate and butyl acetate, ether solvents such as propylene glycol monomethyl ether (hereinafter referred to as PGM), diethyl ether and diisopropyl ether, and the like, and can be used alone or in combination of two or more. .

Organic plastic films to which the present composition is applied include polyester films, polyethylene films, polypropylene films, diacetylcellulose films, triacetylcellulose films, acetylcellulose butyrate films, polyvinyl chloride films, polyvinylidene chloride films, and polyvinyl alcohol films. , ethylene vinyl alcohol film, polystyrene film, polycarbonate film, polymethylpentene film, polysulfone film, polyetheretherketone film, polyethersulfone film, polyetherimide film, polyimide film, fluorine resin film, nylon film, acrylic film, A cycloolefin (co)polymer film and the like can be exemplified.

Among these, biaxially stretched polyester films are preferably used from the viewpoints of price, workability, dimensional stability, etc., and acrylic films and polycarbonate films are preferably used from the viewpoint of weather resistance. The thickness of the film may be approximately 30 μm to 250 μm.

The method of applying the present composition is not particularly limited, and known spray coating, roll coating, die coating, air knife coating, blade coating, spin coating, reverse coating, gravure coating, wire bar coating methods, or gravure printing, screen coating. Printing, offset printing, inkjet printing, etc. can be used. The film thickness to be applied can be exemplified by a dry film thickness of 0.5 μm to 10 μm.

After applying the composition, it is dried at 60 to 120° C. and cured using an ultraviolet irradiation machine. Examples of light sources for ultraviolet irradiation include low-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, carbon arc lamps, xenon lamps, metal halide lamps, electrodeless ultraviolet lamps, and LED lamps. An irradiation intensity of 500 mW/cm ² to 3000 mW/cm ² and an integrated light amount of 50 to 2,000 mJ/cm ² are exemplified. The atmosphere for irradiation may be air or an inert gas such as nitrogen or argon.

The surface resistivity of the HC film coated with the present composition is preferably 1×10 ¹⁴ Ω/□ or less, more preferably 1×10 ¹² Ω/□ or less, particularly 1×10 ¹¹ Ω/□ or less. preferable. An antistatic effect can be exhibited by setting the resistance to 1×10 ¹⁴ Ω/□ or less.

Hereinafter, the present invention will be described in detail based on Examples and Comparative Examples, but these are specific examples and are not particularly limited to these. Unless otherwise specified, measurements were performed under the conditions of a room temperature of 25° C. and a relative humidity of 65%. In addition, the compounding quantity shows a weight part by solid content conversion.

Example 1
(A) Ureac 1 (10-functional, Mw 6,000, acrylic equivalent 600 g / eq, solid content 80% MEK diluted product), (B) SNS-10M (product name: Ishihara Sangyo Co., Ltd.: ATO, average MEK dilution with a particle diameter of 100 nm and a solid content of 30%) as (C), GM-0105 (trade name: acrylic resin particles manufactured by Aica Kogyo Co., Ltd., average particle diameter of 2.0 μm), and Omnirad 184 as (D). (trade name: iGM Co., Ltd.) is used as a leveling agent X-71-1203M (trade name: Shin-Etsu Chemical Co., Ltd., MIBK diluted product with a solid content of 20%), and a diluted solvent is used so that the solid content is 30%. Example 1 was prepared by blending MIBK as a solution and stirring until it was uniformly dissolved and dispersed according to the formulation shown in Table 1.

Examples 2-11
In addition to the materials used in Example 1, Ureac 2 (15-functional, Mw 85,000, acrylic equivalent 5,667 g/eq, solid content 90% diluted toluene) as (A), and 5SM-CL4 as (C) (trade name: manufactured by Admatechs, surface-treated silica, average particle size 0.5 μm) and SS-50F (trade name: manufactured by Tosoh Silica, surface-treated silica, average particle size 1.2 μm) were used as reactive diluents. ACMO (trade name: acryloyl morpholine manufactured by KJ Chemicals Co., Ltd.) was used as a solvent, and MIBK was blended as a dilution solvent so that the solid content was 30%. Examples 2-11 were prepared.

Comparative Examples 1-6
In addition to the materials used in the examples, Ebecryl 1290 (trade name: manufactured by Daicel Ornex Co., Ltd., hexafunctional urethane (meth)acrylate, Mw 1,000, acrylic equivalent 167 g / eq) as a binder, and MEK-50R ( GM-0578S (trade name: manufactured by Aika Kogyo Co., Ltd., acrylic resin particles, average particle size 6.0 μm) as fine particles. And GMX-0610 (trade name: acrylic resin particles manufactured by Aica Kogyo Co., Ltd., average particle size 7.0 μm), MIBK was blended as a dilution solvent so that the solid content was 30%, and the formulation shown in Table 2 Comparative Examples 1 to 6 were prepared by stirring until uniformly dissolved and dispersed.

Table 1

Table 2

Preparation of HC Film for Evaluation This composition was applied to an A4 size polyethylene terephthalate film U403 (trade name: manufactured by Toray Industries, Inc., 100 μm, with easy adhesion layers on both sides) so that the film thickness when cured was 2.5 μm. After drying at 80 ° C. for 1 minute in a constant temperature bath, using an electrodeless UV irradiation device F300S / LC-6B manufactured by Fusion UV System Japan, an H bulb output of 1200 mW / cm2 and an integrated light intensity of 200 mJ / cm2 UV curing is performed to HC for evaluation. adjusted the film.

The evaluation method was as follows.

Total light transmittance: Measured using Haze-GARD2 manufactured by Toyo Seiki Seisakusho Co., Ltd. in accordance with JISK7361-1. 80% or more was evaluated as ◯, and less than 80% as x.

Haze: Measured using Haze-GARD2 manufactured by Toyo Seiki Seisakusho Co., Ltd. in accordance with JISK7361-1. More than 5% was rated as ⊚, 3% to 5% as ◯, and less than 3% as x.

Surface resistivity: Using a high resistance resistivity meter Hirestar UXMCP-HT800 manufactured by Mitsubishi Chemical Analytic, applied voltage 500V, measurement time 1 minute, 1.0 × 10 ¹⁴ Ω / square or less is ○, 1 0×10 ¹² Ω/sq ^.

Abrasion resistance: Using an abrasion tester manufactured by Toyo Seiki Co., Ltd., a load of 200 g is placed on #0000 steel wool with a contact area of 25 mm in diameter, and reciprocated 10 times at a reciprocating speed of 100 times / minute, and scratches are visually observed. The case where there was no scratch was indicated by ○, and the case where there was damage was indicated by ×.

High definition: A hard coat film was placed on a green screen displayed on an iPad (registered trademark: manufactured by Apple Inc.).

Evaluation results Table 3

Evaluation result table 4

The examples had no problems in all aspects of total light transmittance, haze, surface resistivity, abrasion resistance, and high definition.

On the other hand, Comparative Example 1 in which the amount of (C) exceeds the upper limit, Comparative Examples 2 and 3 in which the particle size of (C) exceeds the upper limit are inferior in high definition, and the acrylic equivalent is less than the lower limit. 4 had a high surface resistivity and lacked high definition. Comparative Example 5, in which an ionic antistatic agent was added instead of (B), was inferior in haze, wear resistance, and high definition. Comparative Example 6, in which (B) was not added, had a high surface resistivity. was also unsuitable for the present invention.

Claims (4)

Polyfunctional urethane (meth)acrylate (A), conductive inorganic fine particles (B), fine particles (C) having an average particle diameter of 0.1 to 4 μm (excluding (B)), and a photopolymerization initiator ( D), wherein the acrylic equivalent of (A) is 300 to 30,000 g / eq, and the amount of (C) is 0.5 to 13 parts by weight with respect to 100 parts by weight of (A). An antistatic antiglare film comprising a cured layer of a certain photocurable resin composition. 2. An antistatic antiglare film according to claim 1, wherein said (B) is antimony-doped tin oxide. 3. The antistatic antiglare film according to claim 1, wherein (B) has an average particle size of 10 to 300 nm. The antistatic antiglare film according to any one of claims 1 to 3, wherein (A) has a weight average molecular weight of 1,500 to 300,000.