Curable composition for hard coat

Abstract

[Problem] The present invention addresses the problem of providing a curable composition for a hard coat, said curable composition being developable under low-temperature baking conditions and yielding a cured film having higher transparency and higher hardness than compositions of the prior art. [Solution] Provided is a curable composition for a hard coat, the curable composition containing: a monomer compound that has at least one (meth)acryloyl group per molecule, or a mixture of monomer compounds, as a component (A); a photopolymerization initiator as a component (B); and an organic solvent as a component (C), wherein the hydroxyl value of the compound or mixture of the component (A) exceeds 170 mg KOH / g, and the curable composition for a hard coat is capable of forming a pattern.

Description

Curable composition for hard coat

[0001] The present invention relates to a curable composition for a hard coat that can form a pattern with high hardness and high transparency by low-temperature firing, and a method for forming a cured film using the curable composition for a hard coat.

[0002] A hard coat layer having scratch resistance and weather resistance is provided on the surface of display elements of electronic devices such as touch panel displays, liquid crystal displays, and organic EL displays of smartphones, tablet computers, etc. as a surface protection role.

[0003] As a prior art, a radiation-sensitive composition containing polysilane, a base generator, and a solvent, which gives a highly hard patterned cured product, a cured product of the radiation-sensitive composition, and a method for forming a patterned cured product are disclosed (for example, Patent Document 1). Regarding the firing temperature in Patent Document 1, in paragraph

[0096] , it is described that "the heating temperature (firing temperature) is, for example, 250°C or higher, preferably 300°C or higher. The upper limit of the heating temperature is not particularly limited and may be appropriately set according to the substrate and application, but for example, it is 1000°C or lower, preferably 700°C or lower, and more preferably 600°C or lower." Also, a photosensitive composition containing an alkali-soluble resin, a photopolymerizable monomer, and a photoinitiator, which can form a patterned cured product having excellent organic solvent resistance, high hardness, and a rectangular cross-sectional shape even when heat-treated at a low temperature, a cured product of the photosensitive composition, and a method for manufacturing a patterned cured film using the aforementioned photosensitive composition are disclosed (for example, Patent Document 2).

[0004] Japanese Patent Application Laid-Open No. 2022-75182 International Publication No. 2023 / 127401

[0005] Although Patent Document 1 indicates high hardness, its pencil hardness evaluation is at the 4H level, and transparency and transmittance are not shown. Furthermore, Patent Document 2 states that a maximum transmittance of only 87% was obtained at a wavelength of 400 nm, and in the pencil hardness test of the cured film, the value obtained after one exposure was 3H, and the value obtained after the second exposure was 5H. However, cured films used on the surfaces of display elements in current electronic devices require higher transmittance and higher hardness. In addition, in the formation of cured films using hard coat curable compositions, low-temperature firing is desired because high-temperature firing deteriorates the characteristics of display elements such as organic EL displays. On the other hand, with low-temperature firing, the hardness of the cured film tends to decrease, making it difficult to achieve both high hardness and low-temperature firing.

[0006] Therefore, the problem that the present invention aims to solve is to provide a hard coat curable composition that, in addition to being developable under low-temperature firing conditions, yields a cured film that is more transparent and harder than that of the conventional technology. Specifically, low-temperature firing means firing at a temperature of 120°C or lower, higher transparency means a transmittance of 90% or more, and higher hardness means achieving 6H or higher in a pencil hardness test. Of course, it is necessary to achieve the above simultaneously while ensuring developability that allows for pattern formation.

[0007] As a result of diligent research to solve the above problems, we have found that the above problems can be solved by preparing a composition containing a monomer compound or mixture of monomer compounds having at least one (meth)acryloyl group in one molecule and having a high hydroxyl value above a certain value, a photopolymerization initiator, and an organic solvent, preferably a low boiling point organic solvent, and have completed the present invention.

[0008] In other words, the present invention is a curable hard coat composition that can be patterned, comprising (A) a monomer compound or a mixture of monomer compounds having at least one (meth)acryloyl group in one molecule, (B) a photopolymerization initiator, and (C) an organic solvent, wherein the hydroxyl value of the monomer compound or mixture of monomer compounds (A) is greater than 170 mgKOH / g.

[0009] The (A) monomer compound or mixture of monomer compounds comprises at least one selected from the group consisting of pentaerythritol mono(meth)acrylate, pentaerythritol di(meth)acrylate, and pentaerythritol tri(meth)acrylate, and is a curable composition for pattern-forming hard coats.

[0010] The (A) component is a mixture of monomer compounds, and the mixture is composed of two or more compounds selected from the group consisting of pentaerythritol mono(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, and pentaerythritol tetra(meth)acrylate, making it a curable hard coat composition capable of pattern formation.

[0011] The (C) organic solvent is a curable hard coat composition capable of pattern formation, wherein the organic solvent component contains 40% by mass or more of an organic solvent with a standard boiling point of less than 160°C.

[0012] The (B) photopolymerization initiator is a curable composition for a patternable hard coat, comprising an acylphosphine oxide-based photopolymerization initiator and / or an oxime ester-based photopolymerization initiator.

[0013] The curable hard coat composition for pattern formation is provided in an amount of 0.1 to 15 parts by mass of (B) photopolymerization initiator per 100 parts by mass of (A) monomer compound or mixture of monomer compounds.

[0014] Furthermore, the curable hard coat composition for pattern formation contains (D) a compound having a carboxyl group (excluding the monomer compound (A) or a mixture of monomer compounds) in an amount of 50 parts by mass or less per 100 parts by mass of the monomer compound (A) or a mixture of monomer compounds.

[0015] This is a cured film consisting of a cured product of a hard coat curable composition capable of forming patterns.

[0016] The method for forming a cured film includes the steps of: applying a pattern-forming hard coat curable composition onto a substrate to form a coating film; removing the organic solvent from the coating film by heating; curing the coating film by irradiating it with active energy rays; and removing unexposed areas with a developer to form a pattern.

[0017] This is a method for forming a cured film, wherein the heating temperature is 120°C or lower.

[0018] The pattern-forming hard coat curable composition of the present invention enables pattern formation with high transparency, reliable developability, and high hardness through low-temperature firing. Specifically, it allows for low-temperature firing at 120°C or below, and the patterns formed with the pattern-forming hard coat curable composition of the present invention ensure good developability with no residual film. In addition, the cured film formed from the pattern-forming hard coat curable composition of the present invention achieves a transmittance of 90% or more and a pencil hardness of 6H or higher in the pencil hardness test.

[0019] The pattern-forming hard coat curable composition of the present invention is described below.

[0020] [Curable Composition for Hard Coats] The curable composition for hard coats of the present invention comprises: (A) a monomer compound or a mixture of monomer compounds having at least one (meth)acryloyl group in one molecule; (B) a photopolymerization initiator; and (C) an organic solvent, wherein the hydroxyl value of (A) exceeds 170 mgKOH / g. In addition, it may also contain: (D) a compound having a carboxyl group (except for (A)); and (E) a leveling agent. Each component will be described below.

[0021] [Component (A)] Component (A) is a monomer compound or a mixture of monomer compounds having at least one (meth)acryloyl group in one molecule. Examples of the monomer compounds include pentaerythritol mono(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol mono(meth)acrylate, dipentaerythritol di(meth)acrylate, dipentaerythritol tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate, and dipentaerythritol penta(meth)acrylate. From the viewpoint of achieving both developability and high hardness, it is preferable to use pentaerythritol di(meth)acrylate or pentaerythritol tri(meth)acrylate. In this invention, the term (meth)acrylate compound refers to both acrylate compounds and methacrylate compounds.

[0022] The aforementioned mixture of monomer compounds includes a mixture of two or more monomer compounds selected from the group consisting of the aforementioned monomer compound and pentaerythritol tetra(meth)acrylate.

[0023] [Hydroxyl Value] The hydroxyl value shown in this invention is an index representing the content of hydroxyl groups (-OH) in the sample, and the higher the proportion of hydroxyl groups in the molecule, the higher the hydroxyl value. The hydroxyl value is an index expressed in mg of potassium hydroxide required to neutralize the acetic acid bonded to the hydroxyl groups when acetylating 1 g of the sample. The hydroxyl value of component (A) of this invention is a value greater than 170 mg KOH / g, may be 175 mg KOH / g or higher, preferably 190 mg KOH / g or higher, and more preferably 200 mg KOH / g or higher. If the hydroxyl value of component (A) of this invention is 170 mg KOH / g or lower, either the developability or the pencil hardness will decrease. Generally, a smaller hydroxyl value, that is, a larger amount of (meth)acryloyl groups added, increases the density of (meth)acryloyl groups, resulting in a harder cured film and improved pencil hardness. However, the results differ in this invention, where a hydroxyl value exceeding 170 mgKOH / g is required to achieve high hardness. This is because if the hydroxyl value is less than 170 mgKOH / g, unexposed residue adheres to the surface of the cured film during the development process, negatively affecting the improvement of the hardness of the cured film.

[0024] [Component (B)] Component (B) includes photopolymerization initiators. Examples of photopolymerization initiators include tert-butylperoxy-iso-butyrate, 2,5-dimethyl-2,5-bis(benzoyldioxy)hexane, 1,4-bis[α-(tert-butyldioxy)-iso-propoxy]benzene, di-tert-butylperoxide, 2,5-dimethyl-2,5-bis(tert-butyldioxy)hexenehydroperoxide, α-(iso-propylphenyl)-iso-propylhydroperoxide, tert-butylhydroperoxide, 1,1-bis(tert-butyldioxy)-3,3,5-trimethylcyclohexane, butyl-4,4-bis(tert-butyldioxy)valerate, cyclohexanone peroxide, 2,2',5,5'-tetra(tert-butylperoxycarbonyl)benzophenone, 3, Organic peroxides such as 3',4,4'-tetra(tert-butylperoxycarbonyl)benzophenone, 3,3',4,4'-tetra(tert-amylperoxycarbonyl)benzophenone, 3,3',4,4'-tetra(tert-hexylperoxycarbonyl)benzophenone, 3,3'-bis(tert-butylperoxycarbonyl)-4,4'-dicarboxybenzophenone, tert-butylperoxybenzoate, di-tert-butyldiperoxyisophthalate, etc.; quinones such as 9,10-anthraquinone, 1-chloroanthraquinone, 2-chloroanthraquinone, octamethylanthraquinone, 1,2-benzanthraquinone, etc.; benzoin derivatives such as benzoin methyl, benzoin ethyl ether, α-methylbenzoin, α-phenylbenzoin, etc.2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1-[4-{4-(2-hydroxy-2-methylpropionyl)benzyl}phenyl]-2-methyl-propan-1-one, phenylglyoxylic acid methyl ester, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone, 2-dimethylamino Examples include alkylphenone compounds such as -2-(4-methylbenzyl)-1-(4-morpholine-4-yl-phenyl)-butan-1-one; acylphosphine oxide compounds such as bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide and 2,4,6-trimethylbenzoyl-diphenylphosphine oxide; and oxime ester compounds such as 2-(O-benzoyloxime)-1-[4-(phenylthio)phenyl]-1,2-octanedione, 2-benzoyloximino-4'-(phenylthio)octanophenone, and 1-(O-acetyloxime)-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]ethanone. From the viewpoint of transparency and hardness, it is preferable to use acylphosphine oxide compounds or oxime ester compounds as photopolymerization initiators.

[0025] The aforementioned photopolymerization initiators are commercially available, for example, OMNIRAD® 651, 184, 500, 2959, 127, 754, 907, 369, 379, 379EG, 819, 819DW, 1700, 1870, 784, 1173, MBF, 4265, and TPO (all IGM) Resins Inc.) [formerly IRGACURE® 651, 184, 500, 2959, 127, 754, 907, 369, 379, 379EG, 819, 819DW, 1700, 1870, 784, 1173, MBF, 4265, TPO (all manufactured by BASF Japan Ltd.)], IRGACURE® 1800, OXE01, OXE02 (all manufactured by BASF Japan Ltd.), KAYACURE® DETX, MBP, DMBI, EPA, OA (all manufactured by Nippon Kayaku Co., Ltd.), VICURE-10, 55 (all manufactured by STAUFFER Examples include ESACURE® KIP150, TZT, 1001, KTO46, KB1, KL200, KS300, EB3, Triazine-PMS, Triazine A, Triazine B (all manufactured by DKSH Japan Co., Ltd.), ADEKA optomer N-1717, N-1414, N-1606 (manufactured by ADEKA Corporation).

[0026] The photopolymerization initiator of component (B) can be used alone or in combination of two or more types. The content of component (B) is 0.1 parts by mass to 15 parts by mass, preferably 0.5 parts by mass to 10 parts by mass, and preferably 1 part by mass to 8 parts by mass, per 100 parts by mass of the total amount of component (A). If the content of the photopolymerization initiator of component (B) is less than 0.1 parts by mass, photopolymerization cannot be initiated or polymerization will be insufficient, making pattern formation impossible and reducing the pencil hardness of the cured film. If the content exceeds 15 parts by mass, polymerization will proceed even in unexposed areas, reducing developability, and the transmittance of the cured film will decrease due to the light absorption capacity of the photopolymerization initiator.

[0027] [Component (C)] Component (C) is an organic solvent. In this invention, alcohols, hydrocarbons, esters, ethers, ketones, glycols, and other organic solvents can be used as organic solvents. Furthermore, in this invention, component (C) contains 40% by mass or more of an organic solvent with a standard boiling point of less than 160°C. Hereinafter, those with a standard boiling point of less than 160°C and those with a standard boiling point of 160°C or higher will be listed separately. Examples of alcohols with a standard boiling point of less than 160°C include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-methyl-1-propanol, 2-butanol, 2-methyl-2-propanol, allyl alcohol, propargyl alcohol, isoamyl alcohol, n-amyl alcohol, and cyclopentanol. Alcohols with a standard boiling point of 160°C or higher include 1-heptanol, 1-octanol, 2-octanol, benzyl alcohol, 1-nonanol, 1-decanol, 2-phenyl alcohol, cyclohexanol, 2-methylcyclohexanol, methylcyclohexanol, and 1,5-pentanediol.

[0028] Hydrocarbons with a standard boiling point below 160°C include isopentane, n-pentane, cyclopentane, n-hexane, isohexane, cyclohexene, isoheptane, n-heptane, isooctane, methylcyclohexane, ethylbenzene, toluene, xylene, n-octane, n-nonane, ethylcyclohexane, and cycloooctane. Hydrocarbons with a standard boiling point of 160°C or higher include 1,3,5-trimethylbenzene, isodecane, n-decane, isododecane, decahydronaphthalene, n-undecane, n-dodecane, naphthalene, 1-methylnaphthalene, 2-methylnaphthalene, n-pentadecane, and n-hexadecane.

[0029] Esters with a standard boiling point below 160°C include ethyl formate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, isobutyl acetate, n-amyl acetate, methyl lactate, ethyl lactate, methyl butyrate, ethyl butyrate, propyl butyrate, methyl propionate, ethyl propionate, propyl propionate, butyl propionate, methyl cellosolve acetate, and methoxypropyl acetate. Esters with a standard boiling point of 160°C or higher include methoxybutyl acetate, benzyl acetate, propylene diacetate, dimethyl succinate, benzyl formate, methyl benzoate, ethyl benzoate, ethyl phenyl acetate, butyl lactate, propyl lactate, butyl butyrate, butyl cellosolve acetate, and butyl carbitol acetate.

[0030] Examples of ethers with a standard boiling point of less than 160°C include diethyl ether, dibutyl ether, isopropyl ether, ethylene glycol monomethyl ether, ethylene glycol monopropyl ether, ethylene glycol dimethyl ether, methoxycyclopentane, n-butyl ether, tetrahydrofuran, dioxane, propylene glycol dimethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, and propylene glycol mono-n-propyl ether. Examples of ethers with a standard boiling point of 160°C or higher include isoamyl ether, amyl ether, n-octyl ether, heptyl ether, 1-methoxynaphthalene, 2-methoxynaphthalene, propylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, dipropylene glycol methyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monobutyl ether, tripropylene glycol monomethyl ether, propylene glycol monophenyl ether, methyl triglycol, ethyl triglycol, tripropylene glycol monobutyl ether, ethylene glycol monobutyl ether acetate, and butyl triglycol.

[0031] Ketones with a standard boiling point below 160°C include acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl propyl ketone, diethyl ketone, diisopropyl ketone, cyclopentanone, methyl isoamyl ketone, butyl ethyl ketone, methyl amyl ketone, and cyclohexanone. Ketones with a standard boiling point of 160°C or higher include 2-methylcyclohexanone, diacetone alcohol, 3-methylcyclohexanone, 4-hydroxy-2-butanone, 4-methylcyclohexanone, diisobutyl ketone, hexyl methyl ketone, heptyl methyl ketone, dicyclohexyl ketone, and methyl nonyl ketone.

[0032] Glycols with a standard boiling point below 160°C include ethylene glycol monoethyl ether acetate and propylene glycol monomethyl ether acetate. Glycols with a standard boiling point of 160°C or higher include propylene glycol, 1,2-butylene glycol, hexylene glycol, ethylene glycol, triethylene glycol, dipropylene glycol, glycerin, dipropylene glycol monomethyl ether acetate, and polyethylene glycol.

[0033] Other organic solvents with a standard boiling point below 160°C include acetonitrile and N,N-dimethylformamide. Other organic solvents with a standard boiling point of 160°C or higher include acetamide, dimethyl sulfoxide, N,N-dimethylacetamide, and N-methylpyrrolidone.

[0034] The organic solvent of component (C) can be used alone or in combination of two or more. The content of component (C) is 50% to 150% by mass, preferably 55% to 125% by mass, and more preferably 60% to 120% by mass, based on 100% by mass of the total amount of component (A). In the present invention, among the organic solvents of component (C), the organic solvent with a standard boiling point of less than 160°C is present in the organic solvent component at a concentration of 40% by mass or more, may be 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, and more preferably 85% by mass or more, or 100% by mass. This is because if the organic solvent of component (C) has a standard boiling point of less than 160°C and is present in an amount of less than 40% by mass, organic solvents will remain in the film and the pencil hardness will decrease.

[0035] [Component (D)] Component (D) is a compound having a carboxyl group (excluding component (A) above). Compounds having a carboxyl group include polymers, for example, polymers in which the main chain is preferably a hydrocarbon, acrylic, urethane, aromatic ring, etc., and a carboxyl group is bonded to the main chain as a side chain. As long as a carboxyl group is bonded to the side chain, other groups may also be bonded, for example, hydroxyl groups, hydrocarbon groups, hydrocarbon groups containing double bonds, metachloroyl groups, acryloyl groups, and other groups may be bonded. As a polymer with an aromatic ring as the main chain, for example, a compound in which a carboxyl group is introduced by reacting an acid anhydride with a hydroxyl group produced by adding acrylic acid to a novolac-type epoxy resin. Compounds having a carboxyl group also include compounds obtained by reacting an acid anhydride with an amine compound or a compound having a hydroxyl group. In addition, compounds obtained by oxidizing a compound having a hydroxyl group to obtain a compound having a carboxyl group are also included. Component (D) is available commercially, and examples include 8KQ-2001 (manufactured by Taisei Fine Chemical Co., Ltd.), ARUFON® UC-3000, UC-3080, UC-3510, UF-5080, Aronix® M-510, M-520 (manufactured by Toagosei Co., Ltd.), etc. Component (D) of the present invention is contained in an amount of 50 parts by mass or less, preferably 45 parts by mass or less, and more preferably 43 parts by mass or less, per 100 parts by mass of component (A). This is because if the content of component (D) exceeds 50 parts by mass per 100 parts by mass of component (A), the evaluation of developability, pencil hardness, or transmittance will decrease.

[0036] [Component (E)] Component (E) is a leveling agent. Leveling agents are sometimes used as surfactants or are sometimes classified as surfactants. Examples of leveling agents or surfactants include nonionic surfactants and fluorinated surfactants such as polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene cetyl ether, and polyoxyethylene oleyl ether; polyoxyethylene alkyl allyl ethers such as polyoxyethylene octylphenol ether and polyoxyethylene nonylphenol ether; polyoxyethylene polyoxypropylene block copolymers; sorbitan fatty acid esters such as sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan monooleate, sorbitan trioleate, and sorbitan tristearate; and polyoxyethylene sorbitan fatty acid esters such as polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan trioleate, and polyoxyethylene sorbitan tristearate. The leveling agent or surfactant mentioned above is available commercially, for example, F-Top® EF301, EF303, EF352 (manufactured by Mitsubishi Materials Electronic Chemicals Co., Ltd.), MEGAFACE® EFS-131, EFS-321, EFS-521, EFS-801, F-568, F-551-A, F-551-A, F-554 (manufactured by DIC Corporation), FLUORAD® FC430, FC431 (manufactured by 3M Company), Asahi Guard ( Examples include AG710 (registered trademark, manufactured by AGC Inc.), Surflon (registered trademark) S-382, SC101, SC102, SC103, SC104, SC105, SC106 (manufactured by AGC Seimi Chemical Co., Ltd.), organosiloxane polymer KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.), BYK-302, BYK-307, BYK-322, BYK-323, BYK-330, BYK-333, BYK-370, BYK-375, BYK-378 (manufactured by BYK Corporation), etc.

[0037] The leveling agent of component (E) may be used alone or in combination of two or more types. The content of component (E) can be 0.005 to 10 parts by mass per 100 parts by mass of component (A), preferably 0.01 to 5 parts by mass, and more preferably 0.05 to 1 part by mass. If the content of the leveling agent of component (E) is less than 0.005 parts by mass, the handling properties in the cured film formation process may deteriorate, and if the content exceeds 10 parts by mass, the evaluation of developability, pencil hardness, or transmittance will decrease.

[0038] [Other Additives] The hard coat curable composition of the present invention may contain, as necessary, commonly added additives such as polymerization inhibitors, photosensitizers, surfactants other than those mentioned above, adhesion promoters, plasticizers, ultraviolet absorbers, antioxidants, storage stabilizers, antistatic agents, inorganic fillers, pigments, dyes, etc., as long as they do not impair the effects of the present invention. In addition, polymer component X may be added in addition to component (D) above. Component (D) has a main chain of hydrocarbons, etc., to which carboxyl groups are bonded as side chains, while polymer component X has a main chain of hydrocarbons, acrylics, urethanes, etc., but does not have carboxyl groups in its side chains, and instead has phenol groups in its side chains. Examples of polymer component X include polystyrene.

[0039] [Method of Formation] (Manufacturing Method) The method for forming a cured film includes the steps of: (1) applying a hard coat curable composition capable of forming a pattern onto a substrate to form a coating film; (2) removing an organic solvent from the coating film by heating; (3) curing the coating film by irradiating it with active energy rays; and (4) removing unexposed areas with a developer to form a pattern.

[0040] As the base material in the step (1), for example, various resins (such as polycarbonate, polymethacrylate, polystyrene, polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyurethane, thermoplastic polyurethane (TPU), polyolefin, polyamide, polyimide, epoxy resin, melamine resin, triacetyl cellulose, acrylonitrile-butadiene-styrene copolymer (ABS), acrylonitrile-styrene copolymer (AS), norbornene resin, etc.), silicon, quartz, metal, wood, paper, glass, slate, etc. can be mentioned. The shape of these base materials may be plate-like, film-like or a three-dimensional molded body. The coating method in the step (1) can be appropriately selected from a cast coating method, a spin coating method, a blade coating method, a dip coating method, a roll coating method, a spray coating method, a bar coating method, a die coating method, a roll-to-roll method, an inkjet method, a printing method (such as a relief printing method, an intaglio printing method, a lithographic printing method, a screen printing method, a gravure coating method, etc.). It is preferable to filter the composition using a filter with a pore diameter of about 0.2 μm or the like in advance and then use it for coating.

[0041] The heating in the step (2) is carried out by heating means such as a hot plate or an oven as necessary to remove the organic solvent of the coating film (solvent removal step). As the active energy ray when irradiating the coating film in the step (3) to cure it, ultraviolet rays, electron beams, X-rays, etc. can be mentioned, and ultraviolet rays are particularly preferable. As the light source used for ultraviolet irradiation, sunlight, chemical lamp, low-pressure mercury lamp, high-pressure mercury lamp, metal halide lamp, xenon lamp, UV-LED, etc. can be used. The irradiation of the active energy ray may be carried out under the atmosphere or in an inert gas atmosphere such as nitrogen. Since the composition of the present invention can obtain a sufficient effect even when cured under the atmosphere, from the viewpoints of labor and cost, it is sufficient to irradiate under the atmosphere. Further, thereafter, post-baking may be carried out, specifically, polymerization may be completed by heating using a hot plate, an oven, etc. The developer in the step (4) may be a known developer, and a step of rinsing after development may also be included. A pattern is formed by the step (4).

[0042] Since low-temperature heating is desired from the viewpoint of workability and the properties of the cured film, it is preferable that the heating be at a lower temperature and for a shorter time. The heating conditions in step (2) can be, for example, 40°C to 120°C for about 30 seconds to 10 minutes, preferably 110°C or lower for about 30 seconds to 5 minutes, and even more preferably 105°C or lower for about 30 seconds to 3 minutes.

[0043] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples. The apparatus and conditions used for sample preparation and analysis of physical properties in the examples are as follows.

[0044] Monomer A1: Pentaerythritol polyacrylate (hydroxyl value 275 mg KOH / g) [Aronix® M-933, manufactured by Toagosei Co., Ltd.] Monomer A2: Pentaerythritol polyacrylate (hydroxyl value 200 mg KOH / g) [Aronix® M-934, manufactured by Toagosei Co., Ltd.] Monomer A3: Pentaerythritol polyacrylate (hydroxyl value 150 mg KOH / g) [Aronix® M-306, manufactured by Toagosei Co., Ltd.] Monomer A4: Pentaerythritol polyacrylate (hydroxyl value 110 mg KOH / g) [Aronix® M-305, manufactured by Toagosei Co., Ltd.] Monomer A5: Trimethylolpropane triacrylate (hydroxyl group-free, hydroxyl value 0 mg KOH / g) [A-TMPT, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.] Monomer F: Pentaerythritol (acrylic group-free) [Manufactured by Tokyo Chemical Industry Co., Ltd.] Monomer A6: A mixture of 40% by mass of pentaerythritol polyacrylate (hydroxyl value 200 mg KOH / g) [Aronix® M-934, manufactured by Toagosei Co., Ltd.] and 60% by mass of pentaerythritol polyacrylate (hydroxyl value 150 mg KOH / g) [Aronix® M-306, manufactured by Toagosei Co., Ltd.], resulting in a mixture with a hydroxyl value of 170 mg KOH / g. Photopolymerization initiator B1: 2-benzoyloxyimino-4'-(phenylthio)octanophenone [Irgacure® OXE01, manufactured by BASF Japan Ltd.]. Photopolymerization initiator B2: Bis(2,4,6-(Trimethylbenzoyl)phenylphosphine oxide [Omnirad (registered trademark) 819 manufactured by IGMR resins] Organic solvent C1: Propylene glycol monomethyl ether [manufactured by Kanto Chemical Co., Inc.] Organic solvent C2: Propylene glycol monomethyl ether acetate [manufactured by Kanto Chemical Co., Inc.] Organic solvent C3: Cyclohexanone [manufactured by Resona Co., Ltd.] Organic solvent C4: Dimethylacetamide [manufactured by Kanto Chemical Co., Inc.] Component D1 having a carboxy group: Acrylic polymer having a methacryloyl group and a carboxy group in the side chain [8KQ-2001 manufactured by Taisei Fine Chemical Co., Ltd.] (PGME solution with a solid content concentration of 40% by mass) Component D4 having a carboxy group: Oligomer having a carboxy group [Aronix (registered trademark) M-510 manufactured by Toagosei Co., Ltd.] Polymer component X: Polystyrene having a phenol group in the side chain and no carboxy group [VP-8000 manufactured by Nippon Soda Co., Ltd.] Levelling agent E1: MEGAFACE (registered trademark) EFS-521 (solution diluted from a propylene glycol monomethyl ether acetate solution with a solid content concentration of 20% by mass to a propylene glycol monomethyl ether solution with a solid content concentration of 1% by mass),

[0045] [Production Example 1] Production of Component D3 Having a Carboxy Group 193.6 g of propylene glycol monomethyl ether was weighed into a 1000 mL three-necked flask equipped with a cooling tube and heated to 70 °C in an oil bath under a N ２ atmosphere. 40 g (464.9 mmol) of methacrylic acid, 160 g (1598.1 mmol) of methyl methacrylate, azobisisobutyronitrile (51.6 mmol), and 193.6 g of propylene glycol monomethyl ether were weighed into a 500 mL three-necked flask and stirred with a stirrer to obtain a transparent solution. Then, using a liquid transfer pump from the 500 mL three-necked flask, the solution was transferred to the 1000 mL three-necked flask and stirred at 70 °C for 24 hours. Then, it was cooled to room temperature to obtain an acrylic polymer component D3 having a carboxy group (solid content concentration: 35% by mass).

[0046] [Examples 1 to 13, Comparative Examples 1 to 12] Each component listed in Table 1 was mixed to prepare curable compositions with a solid content concentration of 58% by mass for Examples 1 to 13, Comparative Examples 1 to 9, Comparative Example 11 and Comparative Example 12, and a solid content concentration of 35% by mass for Comparative Example 10. Here, solid content refers to components other than the solvent. Also, in Table 2, [parts] refers to [parts by mass]. In Table 1, components (A), (B), (D), and (E) each represent the solid content. Component (C) refers to all organic solvents in the prepared curable composition, including the organic solvents introduced in components (D) and (E), and organic solvents that were intentionally added. If component (C) is a mixed organic solvent, the proportion of each component is indicated in parentheses.

[0047]

[0048] [Developability] This process was carried out using an automatic coating and developing system ACT-8 (manufactured by Tokyo Electron Ltd.). The curable compositions of Examples 1 to 13 and Comparative Examples 1 to 12 were each coated onto a silicon wafer using a spin coater and soft-baked on a hot plate at 100°C for 1 minute to form coated films with the thicknesses shown in Table 2. The film thickness after soft-baking was measured using an optical film thickness gauge (Lambda Ace VM-2110 (manufactured by Dainippon Screen Mfg. Co., Ltd.)). The obtained coated films after soft-baking were exposed to an i-line stepper NSR-2205i12D (NA = 0.63) (manufactured by Nikon Corporation) on the left half of the silicon wafer at an exposure dose of 50 mJ / cm². ２ The entire surface was exposed, paddle-developed in a 2.38% by mass tetramethylammonium hydroxide (TMAH) aqueous solution for 64 seconds, and rinsed with ultrapure water for 20 seconds. After that, the unexposed area on the right half of the wafer was visually inspected, and judged as ○ if there was no residual film, and × if there was a residual film.

[0049] [Pencil Hardness Test] This procedure was performed using an automatic coating and developing system ACT-8 (manufactured by Tokyo Electron Ltd.). 3-Acryloxypropyltrimethoxysilane was spin-coated onto a silicon wafer at a rotation speed of 3000 rpm, and the wafer was baked on a hot plate at 100°C for 5 minutes to form a primer-treated silicon wafer. On this silicon wafer, the curable compositions of Examples 1 to 13 and Comparative Examples 1 to 12 were applied using a spin coater, and the wafers were soft-baked on a hot plate at 100°C for 1 minute to form coating films with the thicknesses shown in Table 2. The film thickness after soft-baking was measured using an optical film thickness gauge (Lambda Ace VM-2110 (manufactured by Dainippon Screen Mfg. Co., Ltd.)). The obtained soft-baked coating films were exposed to an i-line stepper NSR-2205i12D (NA = 0.63) (manufactured by Nikon Corporation) on the left half of the silicon wafer at an exposure dose of 50 mJ / cm². ２ The entire surface was exposed to light to obtain a cured film. Next, using an automatic coating and developing system ACT-8 (manufactured by Tokyo Electron Ltd.), the wafer was paddle developed for 64 seconds with a 2.38% by mass aqueous solution of tetramethylammonium hydroxide (TMAH), and then rinsed with ultrapure water for 20 seconds. After that, the silicon wafer was subjected to illuminance of 500 mW / cm² in the wavelength range of 320-390 nm using a Heraeus CV-110QC-G lamp (lamp: Heraeus H-bulb high-pressure mercury electrodeless lamp) in an air atmosphere. ２ Exposure dose 1500 mJ / cm ２ The material was exposed to UV light. A pencil hardness test was performed on the resulting cured film. A load of 750g was applied, and the pencil was slid four times with pencils of each hardness at a sliding speed of 60mm / min. Afterwards, the sliding area was lightly wiped with Bencot, and the presence or absence of scratches caused by the pencil sliding was visually judged. The hardness with the highest level of no scratches observed in three or more of the four trials was adopted as the evaluation result. For hard coats, it is preferable that the pencil hardness of the cured film be 6H or higher from the viewpoint of scratch prevention.

[0050] [Composition Homogeneity] The appearance of each prepared curable composition was visually inspected and evaluated according to the following criteria: ○: Transparent solution (no suspended matter, sediment, or phase separation) ×: Presence of any of the following: suspended matter, sediment, or phase separation

[0051] [Transmittance Measurement] Each of the curable compositions listed in Table 1 was applied to a quartz substrate using a spin coater and pre-baked on a hot plate at 100°C for 1 minute. Using a Heraeus CV-110QC-G (lamp: Heraeus H-bulb high-pressure mercury electrodeless lamp), exposure was 1500 mJ / cm² in an atmospheric environment with a wavelength range of 320-390 nm. ２ The entire surface was exposed by irradiating it with UV light. One day after exposure, the transmittance at a wavelength of 400 nm was measured for these cured films using a UV-2600 ultraviolet-visible spectrophotometer (manufactured by Shimadzu Corporation). The evaluation results are shown in Table 2.

[0052]

[0053] As shown in Table 2, the cured films obtained from the curable compositions of Examples 1 to 13 exhibited excellent developability, pencil hardness, and transparency.

[0054] As shown in Table 1, the curable compositions of Examples 1 and 7, as well as Comparative Examples 3 to 5 and 11, are composed of the same components except for the difference in the hydroxyl value of component (A). As shown in Table 2, the cured films obtained from the curable compositions of Comparative Examples 3 to 5 and 11 have inferior developability compared to the cured films obtained from the curable compositions of Examples 1 and 7. In addition, the cured films obtained from the curable compositions of Comparative Examples 4 and 5 have lower pencil hardness compared to the cured films obtained from the curable compositions of Examples 1 and 7. These results indicate that in applications where both developability and high hardness are required, the hydroxyl value of component (A) needs to be greater than 170 mgKOH / g.

[0055] Furthermore, as shown in Table 1, the difference between the curable composition of Example 4 and the curable compositions of Examples 1 to 3 and Examples 11 to 13 is whether or not it contains component (D), and the hydroxyl value of component (A) is 275 mg KOH / g in all cases. The pencil hardness of the cured films obtained from the curable compositions of Examples 1 to 3 and Examples 11 to 13 containing component (D) is equal to or greater than that of the cured film obtained from the curable composition of Example 4 that does not contain component (D), indicating that the addition of component (D) has an effect of improving pencil hardness. On the other hand, the difference between the curable composition of Comparative Example 2 and the curable composition of Comparative Example 4 is whether or not it contains component (D), and the hydroxyl value of component (A) is 110 mg KOH / g in all cases. The pencil hardness of the cured film obtained from the curable composition of Comparative Example 4 containing component (D) was lower than that of the cured film obtained from the curable composition of Example 2 that did not contain component (D). This indicates that when the hydroxyl value of component (A) is 170 mgKOH / g or less, the addition of component (D) adversely affects the hardness of the cured film. These results are thought to be due to the difference in hydrogen bonding properties between component (A) and component (D), which is caused by the hydroxyl value of component (A), resulting in different photocurability.

[0056] Furthermore, as shown in Table 1, the (C) component of the curable composition of Example 9 contains an organic solvent with a higher standard boiling point than the organic solvent of the (C) component of the curable composition of Example 7. The cured film obtained from the curable composition of Example 9 tends to have lower pencil hardness than the cured film obtained from the curable composition of Example 7. Similarly, the (C) component of the curable composition of Example 10 contains an organic solvent with a higher standard boiling point than the organic solvent of the (C) component of the curable composition of Example 1. The cured film obtained from the curable composition of Example 10 tends to have lower pencil hardness than the cured film obtained from the curable composition of Example 1. These results are thought to be due to residual organic solvent in the cured film, and it is preferable that the standard boiling point of the (C) component is low.

[0057] Furthermore, as shown in Table 1, the curable compositions of Examples 1 to 13 have a standard boiling point of component (C) of less than 160°C. On the other hand, the curable composition of Comparative Example 9 contains 65% by mass of an organic solvent with a standard boiling point of 160°C or higher in component (C). The pencil hardness of the cured film obtained from the curable composition of Comparative Example 9 is lower than that of the cured films obtained from the curable compositions of Examples 1 to 13. This is because the organic solvent with a standard boiling point of 160°C or higher remains in the cured film obtained from the curable composition of Comparative Example 9. Therefore, it is preferable that the standard boiling point of component (C) is less than 160°C, and that the content of organic solvents with a standard boiling point of 160°C or higher in component (C) is low.

[0058] Furthermore, as shown in Table 1, the curable composition of Comparative Example 12 is obtained by changing component (D) of the curable composition of Example 1 to polymer component X having a phenol group in its side chain. The cured film obtained from the curable composition of Example 1 has a higher pencil hardness than the cured film obtained from the curable composition of Comparative Example 12. This result can be explained by the following reason. The hydrogen bonding strength with the hydroxyl group of component (A) is stronger for the carboxyl group than for the phenol group. Therefore, more of component (A) is attracted to the area around component (D) compared to the area around polymer component X, and the concentration of component (A) around component (D) increases. The concentration of (meth)acryloyl groups derived from component (A) also increases, improving reactivity (curability), and thus the cured film obtained from the curable composition of Example 1 has a higher pencil hardness than the cured film obtained from the curable composition of Comparative Example 12. In other words, it is necessary to use a compound having a carboxyl group instead of a compound having a phenol group as component (D).

Claims

1. A curable hard coat composition capable of pattern formation, comprising (A) a monomer compound or mixture of monomer compounds having at least one (meth)acryloyl group in one molecule, (B) a photopolymerization initiator, and (C) an organic solvent, wherein the hydroxyl value of the monomer compound or mixture of monomer compounds (A) exceeds 170 mgKOH / g.

2. The pattern-forming hard coat curable composition according to claim 1, wherein the monomer compound (A) or mixture of monomer compounds comprises at least one selected from the group consisting of pentaerythritol mono(meth)acrylate, pentaerythritol di(meth)acrylate, and pentaerythritol tri(meth)acrylate.

3. The pattern-forming hard coat curable composition according to claim 1, wherein component (A) is a mixture of monomer compounds, and the mixture consists of two or more compounds selected from the group consisting of pentaerythritol mono(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, and pentaerythritol tetra(meth)acrylate.

4. The pattern-forming hard coat curable composition according to any one of claims 1 to 3, wherein the (C) organic solvent contains 40% by mass or more of an organic solvent with a standard boiling point of less than 160°C in the organic solvent component.

5. The patternable hard coat curable composition according to any one of claims 1 to 3, wherein the (B) photopolymerization initiator comprises an acylphosphine oxide-based photopolymerization initiator and / or an oxime ester-based photopolymerization initiator.

6. A curable hard coat composition for pattern formation according to any one of claims 1 to 3, wherein the amount of (B) photopolymerization initiator is 0.1 to 15 parts by mass per 100 parts by mass of (A) monomer compound or mixture of monomer compounds.

7. The pattern-forming hard coat curable composition according to any one of claims 1 to 3, further comprising (D) a compound having a carboxyl group (excluding the monomer compound (A) or a mixture of monomer compounds) in an amount of 50 parts by mass or less per 100 parts by mass of the monomer compound (A) or a mixture of monomer compounds.

8. A cured film comprising a cured product of a pattern-forming hard coat curable composition according to any one of claims 1 to 3.

9. A method for forming a cured film, comprising the steps of: applying a pattern-forming hard coat curable composition according to any one of claims 1 to 3 onto a substrate to form a coating film; removing the organic solvent from the coating film by heating; curing the coating film by irradiating it with active energy rays; and removing unexposed areas with a developer to form a pattern.

10. The method for forming a cured film according to claim 9, wherein the heating temperature is 120°C or lower.

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