JP4137133B2 - Hard coat agent and hard coat film - Google Patents

Description

  The present invention relates to a hard coat agent and a hard coat film.

  In addition to its processability and transparency, plastic film is lightweight and inexpensive, so it has been used in various industries such as the automobile industry and household appliance industry instead of glass. Flat panels such as plasma displays and liquid crystal displays It is also widely used for displays such as displays, touch panels and personal computers. However, it has drawbacks such as being softer than glass and being easily scratched on the surface.

In order to remedy this drawback, a hard coat agent is used in which metal oxide fine particles such as alumina, silica, zirconium oxide, zinc oxide, and silica are blended in a silicone or acrylic resin binder. This hard coat agent can be applied to the surface of the film and dried, followed by heating or curing with ultraviolet rays to produce a hard coat film that is less susceptible to scratches on the surface.
JP2002-220487A JP-A-2005-194363 JP2001-13303

  However, since the hard coat film provided with the hard coat layer on both sides becomes smooth on the coated surface, it cannot be wound as it is in the production of Roll to Roll, and a method of sticking a protective film on one side is taken. It was. Moreover, when using for a touch panel use, the heat resistant problem and the change of the manufacturing line may be needed by having bonded the protective film.

  The present invention has been studied in order to solve the above problems, and 0.5 to 50 parts by weight of organic fine particles having an average primary particle diameter of 80 to 500 nm are blended with respect to 100 parts by weight of a polyfunctional polymerizable monomer. This is a hard coat agent.

  By using organic fine particles having an average primary particle diameter of 80 to 500 nm with respect to 100 parts by weight of the polyfunctional polymerizable monomer, fine irregularities are formed on the coated surface, and the coating film contact area when bonding both coated surfaces together As a result, the frictional force is reduced, and as a result, the slipperiness is improved, so that Roll to Roll can be produced without using a protective film, which is economically inexpensive. Furthermore, the hard coat agent of the present invention can also be used as a resin for insert molding films. Hereinafter, the present invention will be described in detail.

  In the present invention, a polyfunctional polymerizable monomer is used as the binder component. The polyfunctional polymerizable monomer has at least two (meth) acryloyl groups, vinyl groups, and allyl groups in the molecule. Among them, those having a (meth) acryloyl group have very high radical reactivity, and are superior in terms of fast curing and high hardness. Specifically, dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, penta Examples include polyfunctional (meth) acrylates such as erythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, hexanediol di (meth) acrylate, and diethylene glycol di (meth) acrylate. . These may be used alone or in combination.

  Among the polyfunctional (meth) acrylates, dipentaerythritol hexaacrylate is particularly preferable because of excellent scratch resistance and transparency of the hard coat layer.

  Examples of the organic fine particles according to the present invention include organic fine particles such as styrene resins, styrene-acrylic copolymer resins, and acrylic resins synthesized by an emulsion polymerization method. It is difficult to synthesize organic fine particles having an average primary particle size of 80 to 500 nm by suspension polymerization methods other than emulsion polymerization, and the addition amount of the crosslinking agent cannot be increased by dispersion polymerization. An emulsion polymerization method in which a cross-linking agent can be easily added is preferred because it cannot dissolve in the surface and cannot form irregularities on the surface when cured on a plastic film.

  The average primary particle diameter of the organic fine particles is preferably 80 to 500 nm. In the emulsion polymerization method, it is difficult to synthesize organic fine particles when the average primary particle diameter is less than 80 nm or more than 500 nm. Also, if it is less than 80 nm, the amount of addition required for forming irregularities on the surface increases, so hard coat performance cannot be obtained, but if it exceeds 500 nm, the haze increases and the visibility deteriorates. To do. The shape of the organic fine particles is preferably spherical or beaded, but is not particularly limited thereto. The average primary particle diameter is the diameter of a single particle that has not been agglomerated. For spherical particles, the diameter is indicated, and for particles other than the spherical shape, the arithmetic average value of the major axis diameter and the minor axis diameter is indicated. The value measured by an electron microscope.

  The addition amount of the organic fine particles is preferably 0.5 to 50 parts by weight with respect to 100 parts by weight of the resin solid content of the polyfunctional polymerizable monomer, and if it is less than 0.5 parts by weight, surface irregularities can be formed. In addition, if it exceeds 50 parts by weight, sufficient hard coat performance cannot be exhibited. When used for a hard coat film, 0.5 to 50 parts by weight is preferred. More preferably, it is 1-20 weight part.

  In the present invention, 0.1 to 5 parts by weight of a dispersant may be blended with respect to 100 parts by weight of the fine particles in order to prevent aggregation of the organic fine particles and ensure excellent dispersibility and dispersion stability. Examples of the dispersant include various surfactants. For example, anionic surfactants such as sulfate esters, carboxylic acids, and polycarboxylic acids, cationic surfactants such as quaternary salts of higher aliphatic amines, and nonionic surfactants such as higher fatty acid polyethylene glycol esters Agents, silicon surfactants, fluorine surfactants, polymer surfactants having an amide ester bond, and the like.

  A radical polymerization initiator is added to the hard coat agent of the present invention, and the radical polymerization initiator is not particularly limited, and various known ones can be used. As radical type polymerization initiators, benzophenone and other acetophenones, benzyl, benzaldehyde and o-chlorobenzaldehyde, xanthone, thioxanthone, 2-chlorothioxanthone, 9,10-phenanthrenequinone, 9,10-anthraquinone, methylbenzoin ether, ethyl Benzoin ether, isopropyl benzoin ether, α, α-diethoxyacetophenone, α, α-dimethoxyacetophenone, 1-phenyl-1,2-propanediol-2-o-benzoyloxime and α, α-dimethoxy-α-phenylacetophenone Etc. Commercially available products include photoinitiators such as Irgacure-184, Irgacure-651 (manufactured by Ciba Specialty Chemicals), Darocur-1173 (manufactured by Merck), benzoyl peroxide, t-butyl-peroxybenzoate, azo Bisisobutyronitrile, diacetyl peroxide, dipropyl peroxide, dibutyl peroxide, dicapryl peroxide, benzoyl peroxide, p, p'-dichlorobenzoyl peroxide, p, p'-dimethoxybenzoyl peroxide, p, and thermal initiators such as p′-dimethylbenzoyl peroxide. The addition amount is 1 to 10 parts by weight with respect to 100 parts by weight of the resin solid content of the polymerizable polyfunctional monomer.

  In addition, an organic solvent can be added. Examples of the organic solvent include aliphatic hydrocarbons such as hexane, heptane and cyclohexane, aromatic hydrocarbons such as toluene and xylene, halogenated hydrocarbons such as methylene chloride and ethylene chloride, methanol, ethanol, propanol, Examples include alcohols such as butanol, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, 2-pentanone and isophorone, esters such as ethyl acetate and butyl acetate, and cellosolve solvents such as ethyl cellosolve.

  Other additives such as antistatic agents, refractive index adjusting agents, antioxidants, ultraviolet absorbers, light stabilizers, photosensitizers, leveling agents, antifoaming agents, inorganic fillers, coupling agents, Preservatives, plasticizers, flow regulators, thickeners, pH adjusters, and the like may be used as blending materials.

  The plastic film as the substrate to which the hard coat agent of the present invention is applied is, for example, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyethylene film, polypropylene film, cellophane, diacetylcellulose film, triacetylcellulose film, acetylcellulose. Butyrate film, polyvinyl chloride film, polyvinylidene chloride film, polyvinyl alcohol film, ethylene-vinyl acetate copolymer film, polystyrene film, polycarbonate film, polymethylpentene film, polysulfone film, polyether ether ketone film, polyether sulfone Film, polyetherimide film, polyimide film, fluorine resin fill , Nylon film, can be used an acrylic resin film, any known.

  In addition, for the purpose of improving the adhesion with the hard coating agent of the present invention, surface unevenness treatment by sandblasting method or solvent treatment method, corona discharge treatment, chromic acid treatment, flame treatment, hot air treatment, ozone / ultraviolet ray Surface treatment such as surface oxidation treatment such as irradiation treatment and electron beam irradiation treatment may be performed.

  There are no particular restrictions on the coating method and coating thickness of the hard coat agent of the present invention, and known methods such as gravure coating method, bar coating method, knife coating method, roll coating method, blade coating method, die coating method, etc. The film can be applied after drying so that the thickness of the coating film is 10 μm or less. When the thickness exceeds 10 μm, there is a problem in handling such as the produced film warps. More preferably, it is 2-5 micrometers.

When irradiating an electron beam, an electron beam accelerator of a scanning type or a curtain type is used, and has an acceleration voltage of 1000 keV or less, preferably 100 to 300 keV. When irradiating ultraviolet rays, an ultrahigh pressure mercury lamp, a high pressure mercury lamp, Using a low-pressure mercury lamp, carbon arc, metal halide lamp or the like, ultraviolet rays having an energy of 100 to 800 mJ / cm ² are irradiated in a wavelength region of 100 to 400 nm, preferably 200 to 400 nm. Moreover, you may harden | cure in nitrogen atmosphere as needed.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and demonstrated in detail about this invention, a specific example is shown and it does not specifically limit to these.

(1) Production of solvent-dispersed acrylic resin (a) Solvent-dispersed slurry A
In a polymerization vessel equipped with a stirrer, thermometer, reflux condenser and nitrogen gas inlet, 120 parts by weight of deionized water, 0.8 part by weight of sodium dialkylsulfosuccinate and 0.4 part by weight of sodium bicarbonate as a pH buffering agent Was heated to 60 ° C. with stirring, and then purged with nitrogen. To this was added 2 parts by weight of methyl methacrylate, and 10 minutes later, 0.1 part by weight of sodium persulfate dissolved in 0.98 parts by weight of deionized water was added to perform seed polymerization. 60 minutes after the start of heat generation, 0.1 part by weight of sodium persulfate dissolved in 4.9 parts by weight of deionized water was added, and after another 10 minutes, 78.4 parts by weight of t-butyl acrylate, ethylene glycol dimethacrylate An emulsified monomer solution consisting of 19.6 parts by weight, 60 parts by weight of deionized water, 1.2 parts by weight of sodium dialkylsulfosuccinate, and 0.5 parts by weight of sodium bicarbonate was stirred for 3 hours while maintaining the temperature at 80 ° C. The solution was dropped over a period of 2 hours and maintained at 85 ° C. for 2 hours to complete the polymerization to obtain an aqueous latex (A-1). The product (A-1) had a solid content of 34.1% and an average primary particle size of 115 nm.

  Organic fine particle aggregates were taken out by salting out the aqueous latex (A-1) synthesized above.

  100 parts by weight of the above organic fine particle aggregates were added to 570 parts of isopropyl alcohol little by little while confirming the dispersion state with stirring to obtain a non-aqueous fine particle dispersion (A-2). The product (A-2) had a solid content of 15.0%.

(B) Solvent dispersed slurry B
In a polymerization vessel equipped with a stirrer, thermometer, reflux condenser and nitrogen gas inlet, 120 parts by weight of deionized water, 0.8 part by weight of sodium dialkylsulfosuccinate and 0.4 part by weight of sodium bicarbonate as a PH buffering agent Was heated to 60 ° C. with stirring, and then purged with nitrogen. To this was added 2 parts by weight of methyl methacrylate, and 10 minutes later, 0.1 part of sodium persulfate dissolved in 0.98 parts by weight of deionized water was added to carry out seed polymerization. 60 minutes after the start of heat generation, 0.1 part by weight of sodium persulfate dissolved in 4.9 parts by weight of deionized water was added, and after another 10 minutes, 65.7 parts by weight of t-butyl acrylate, ethylene glycol dimethacrylate An emulsified monomer solution composed of 29.4 parts by weight, 2.9 parts by weight of 2-hydroxyethyl methacrylate, 60 parts by weight of deionized water, 1.2 parts by weight of sodium dialkylsulfosuccinate, and 0.5 parts by weight of sodium bicarbonate was stirred. The temperature was kept at 80 ° C. for 3 hours, and after completion of the dropwise addition, the temperature was maintained at 85 ° C. for 2 hours to complete the polymerization to obtain an aqueous latex (B-1). The product (B-1) had a solid content of 34.3% and an average primary particle size of 117 nm.

  An ion exchange resin (Amberlite MB-2, manufactured by Rohm and Haas) 25 for the purpose of removing ionic impurities that hinder phase inversion to an organic solvent in the aqueous latex (B-1) synthesized above. A part by weight was added and stirred. After stirring for 24 hours, the ion exchange resin was removed by filtration to obtain an aqueous latex (B-2) having an unlimited amount of ionic impurities.

  To this purified aqueous latex (B-2), 570 parts by weight of ethyl acetate was added and stirred, and the organic fine particles present in the aqueous latex were phase-inverted to the organic layer. Thereafter, the mixture was allowed to stand to separate a transparent aqueous phase and a cloudy organic phase, thereby obtaining a non-aqueous fine particle dispersion (B-3). The product (B-3) had a solid content of 14.9%.

(C) Solvent dispersed slurry C
In a polymerization vessel equipped with a stirrer, thermometer, reflux condenser and nitrogen gas inlet, 120 parts by weight of deionized water, 0.8 part by weight of sodium dialkylsulfosuccinate and 0.4 part by weight of sodium bicarbonate as a pH buffering agent Was heated to 60 ° C. with stirring, and then purged with nitrogen. To this was added 2 parts by weight of methyl methacrylate, and 10 minutes later, 0.1 part by weight of sodium persulfate dissolved in 0.98 parts by weight of deionized water was added to perform seed polymerization. 60 minutes after the start of heat generation, 0.1 part by weight of sodium persulfate dissolved in 4.9 parts by weight of deionized water was added, and after another 10 minutes, 43.7 parts by weight of methyl methacrylate and 29.1 parts by weight of styrene The emulsion monomer liquid consisting of 24.2 parts by weight of ethylene glycol dimethacrylate, 60 parts by weight of deionized water, 1.2 parts by weight of sodium dialkylsulfosuccinate and 0.5 parts by weight of sodium bicarbonate was stirred and the temperature was adjusted to 80 ° C. The mixture was added dropwise over 3 hours while maintaining the temperature and maintained at 85 ° C. for 2 hours after the completion of the dropwise addition to complete the polymerization to obtain an aqueous latex (C-1). The product (C-1) had a solid content of 34.1% and an average primary particle size of 109 nm.

  To the aqueous latex (C-1) synthesized above, 25 parts by weight of an ion exchange resin was added and stirred for the purpose of removing ionic impurities that hindered phase inversion to an organic solvent. After stirring for 24 hours, the ion exchange resin was removed by filtration to obtain an aqueous latex (C-2) having an unlimited amount of ionic impurities.

To the purified aqueous latex (C-2), 570 parts by weight of ethyl acetate was added and stirred, and the organic fine particles present in the aqueous latex were phase-inverted to the organic layer. Thereafter, the mixture was allowed to stand to separate a transparent aqueous phase and a cloudy organic phase to obtain a non-aqueous fine particle dispersion (C-3). The product (C-3) had a solid content of 15.1%.
(D) Solvent dispersed slurry D
In a polymerization vessel equipped with a stirrer, thermometer, reflux condenser and nitrogen gas inlet, 120 parts by weight of deionized water, 0.3 part by weight of sodium dialkylsulfosuccinate and 0.1 part by weight of sodium bicarbonate as a pH buffering agent Was heated to 60 ° C. with stirring, and then purged with nitrogen. To this was added 2 parts by weight of methyl methacrylate, and 10 minutes later, 0.1 part by weight of sodium persulfate dissolved in 0.98 parts by weight of deionized water was added to perform seed polymerization. 60 minutes after the start of heat generation, 0.1 part by weight of sodium persulfate dissolved in 4.9 parts by weight of deionized water was added, and after another 10 minutes, 43.7 parts by weight of methyl methacrylate and 29.1 parts by weight of styrene The emulsion monomer solution consisting of 24.2 parts by weight of ethylene glycol dimethacrylate, 60 parts by weight of deionized water, 0.8 parts by weight of sodium dialkylsulfosuccinate, and 0.3 parts by weight of sodium bicarbonate was stirred at a temperature of 80 ° C. The mixture was added dropwise over 3 hours while maintaining the temperature and maintained at 85 ° C. for 2 hours after the completion of the dropwise addition to complete the polymerization to obtain an aqueous latex (D-1). The product (D-1) had a solid content of 33.9% and an average particle size of 489 nm.

  To the aqueous latex (D-1) synthesized above, 15 parts by weight of an ion exchange resin was added and stirred for the purpose of removing ionic impurities that hindered phase inversion to an organic solvent. After stirring for 24 hours, the ion exchange resin was removed by filtration to obtain an aqueous latex (D-2) having an unlimited amount of ionic impurities.

To the purified aqueous latex (D-2), 570 parts by weight of ethyl acetate was added and stirred, and the organic fine particles present in the aqueous latex were phase-inverted to the organic layer. Thereafter, the mixture was allowed to stand to separate a transparent aqueous phase and a cloudy organic phase to obtain a non-aqueous fine particle dispersion (D-3). The product (D-3) had a solid content of 15.0%.
(1) Synthesis of Acrylic Resin Dipentaerythritol hexaacrylate (Shin Nakamura Chemical Co., Ltd., trade name: A-DPA solid content: 100%) 100 parts by weight of solvent dispersion type slurry A (product A-3) 20 And 113 parts by weight of methyl ethyl ketone (MEK) as a diluent solvent were mixed and stirred. As a leveling agent, 0.3 parts by weight of Byketol-OK (manufactured by BYK Japan Co., Ltd.) and 3 parts by weight of Irgacure 184 (manufactured by Ciba Specialty Chemicals) as an initiator were added to obtain a hard coat agent.
(2) Production of hard coat film Subsequently, a hard coat agent was applied to a PET film having a thickness of 100 μm (polyethylene terephthalate: trade name Lumirror U34 manufactured by Toray Industries, Inc.) so that the film thickness after curing was 3 μm. And an ultraviolet treatment with an irradiation intensity of 1500 mW / cm ² and a work amount of 300 mJ / cm ² was performed using an ultraviolet irradiator to obtain a hard coat film.

  A hard coat film was obtained in the same manner as in Example 1 except that the solvent-dispersed slurry A was changed to the solvent-dispersed slurry B (product B-3) instead of the solvent-dispersed slurry A.

  A hard coat film was obtained in the same manner as in Example 2 except that the dry film thickness was changed to 7 μm.

  In Example 1, instead of the solvent-dispersed slurry A, a hard-coated film was carried out in the same manner except that the solvent-dispersed slurry C (product C-3) was changed to 133 parts by weight and MEK was changed to 17 parts by weight. Got.

  In Example 1, trimethylolpropane triacrylate (manufactured by Kyoeisha Chemical Co., Ltd., trade name Light Acrylate TMP-A) was used in place of A-DPA, and solvent dispersed slurry A (production) with respect to 100 parts by weight of TMP-A A hard coat film was obtained in the same manner except that the product A-3) was changed to 20 parts and the MEK was changed to 113 parts.

  In Example 6, instead of the solvent-dispersed slurry D, the solvent-dispersed slurry C (product C-3) was changed to 67 parts by weight, MEK was changed to 73 parts by weight, the dry film thickness was 2 μm, and the atmosphere was nitrogen. A hard coat film was obtained in the same manner except that the film was cured.

(Film for insert molding)
In Example 6, instead of the solvent-dispersed slurry D, the solvent-dispersed slurry C (product C-3) was changed to 67 parts by weight, MEK was changed to 73 parts by weight, the dry film thickness was 2 μm, and in a nitrogen atmosphere. A hard coat film for insert molding was obtained in the same manner except for curing at.

(Film for insert molding)
In Example 7, 335.6 parts by weight of the solvent-dispersed slurry C (product C-3), a dry film thickness of 7 μm without adding MEK, was carried out in the same manner except that it was cured in the atmosphere, A hard coat film for insert molding was obtained.

Comparative Example 1
A coating film was obtained in the same manner as in Example 2 except that the addition amount of the solvent-dispersed slurry B was changed to 2 parts by weight and the addition amount of MEK was changed to 148 parts by weight.

Comparative Example 2
A coating film was obtained in the same manner as in Example 2 except that the amount of the solvent-dispersed slurry B added was 400 parts by weight and the MEK was not added.

Comparative Example 3
A coating film was obtained in the same manner as in Example 1 except that the dry film thickness was changed to 11 μm.

Comparative Example 4
A coating film was obtained in the same manner as in Example 4 except that the dry film thickness was changed to 11 μm.

Comparative Example 5
The solvent-dispersed slurry A was applied to a PET film having a thickness of 100 μm and dried so that the dry film thickness after curing was 3 μm, thereby obtaining a coating film.
The evaluation results are shown in Table 1.

Test / Evaluation Method (1) Measurement of Total Light Transmittance (Tt) Measured based on the provisions of JIS K 7361-1 (2000 version) 3.2. As a measuring device, Hazeguard II manufactured by Toyo Seiki Seisakusho Co., Ltd. was used.
(2) Measurement of haze value (Hz) The haze value (Hz) was measured with a haze meter (manufactured by Suga Test Instruments Co., Ltd.) based on the provisions of JIS K 7136 (2000 version). As a measuring device, Hazeguard II manufactured by Toyo Seiki Seisakusho Co., Ltd. was used.
(3) Measurement of pencil hardness It was performed according to the provisions of JIS K 5600-5-4 (1999 edition). As a measuring apparatus, a pencil scratch coating film hardness tester (type P) manufactured by Toyo Seiki Seisakusho Co., Ltd. was used.
(4) Measurement of scratch resistance The surface of the hard coat film was rubbed with steel wool # 0000 manufactured by Nippon Steel Wool Co., Ltd. with a load of 2 kg, and the degree of scratch was visually evaluated. The case where no scratch was found was marked with ◎, the number of three or less was marked with ◯, and the number of scratches was marked with x.
(5) Measurement of sliding property A commercially available hard coat film (HC-2300, manufactured by Aika Kogyo Co., Ltd.) is slid on the surface of the produced hard coat film. Those that slide well are marked with ◎.
(6) Warpage Evaluation Method A sample of 15 cm square was prepared, and the warpage at the four corners was measured.

Claims (2)

The polyfunctional polymerizable monomer 100 parts by weight, synthesized by emulsion polymerization method using a bifunctional or more (meth) acrylate, a step or an ion exchange resin is replaced with isopropyl alcohol solvent Ri by the salting of water A hard coat agent comprising 0.5 to 50 parts by weight of organic fine particles having an average primary particle size of 80 to 500 nm after passing through a step of replacing the solvent with water by ethyl acetate . When the hard coat agent according to claim 1 is applied to a transparent plastic film, the film thickness in a dry state is 10 μm or less, the total light transmittance measured based on JIS K 7361-1 is 90% or more, JIS K A hard coat film having a haze value measured on the basis of 7136 of 1.5% or less.