TWI860985B - Thermosetting conposition,cured film thereof,and display device with the same - Google Patents

Abstract

Provided is a thermosetting composition capable of forming a protective film having excellent flatness, heat resistance, chemical resistance, adhesion, hardness, electrical reliability and transparency. (1): A thermosetting composition comprising: an epoxy compound (A) represented by the following general formula (1) wherein the average value of m is 0 to 1; an epoxy compound (B) which is liquid at room temperature; an epoxy compound (C) other than the component (A) or the component (B) having a weight average molecular weight of 900 to 20,000 and an epoxy equivalent of 150 g/eq to 500 g/eq; a curing agent (D) selected from the group consisting of polycarboxylic acids, polycarboxylic acid anhydrides, and polycarboxylic acid thermally decomposable esters; and a curing accelerator (E) (in the general formula (1), Ar is a divalent aromatic hydrocarbon group having 6 to 12 carbon atoms, and a portion of the hydrogen atoms of the divalent aromatic hydrocarbon group may be substituted by a hydrocarbon group having 1 to 10 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or a halogen group).

Description

Thermosetting composition, cured film and display device

The present invention relates to a thermosetting composition, a cured film formed by curing the thermosetting composition, and a display device having the cured film.

In the past, a transparent hardened film (hereinafter also referred to as a protective film) was formed as a protective layer on the surface of the color filter used in the manufacture of a color liquid crystal display (LCD). The protective film of the color filter can be formed for the following purposes: to flatten the unevenness generated between the pixels of the color filter, to improve the durability of the color filter to the heat treatment or chemical treatment in the subsequent step, to improve the reliability of the color liquid crystal display, etc. As a protective film of the color filter, it is required to have excellent flatness, heat resistance, chemical resistance, adhesion, hardness, electrical reliability and transparency.

For example, in terms of flatness, it is required to flatten the unevenness of about 1 μm to 2 μm in height caused by repeated coating of the coloring composition when forming pixels to less than 0.1 μm. In terms of heat resistance, there is a situation where a high temperature of about 200°C to 270°C is applied to the protective film when a transparent electrode such as indium tin oxide (ITO) is made by sputtering, and the protective film is required to be stable under the above temperature conditions. In terms of chemical resistance, the protective film is required to be stable to acids, alkalis, and solvents used in subsequent steps. In terms of adhesion, when manufacturing a liquid crystal display panel, a substrate is sometimes bonded to the protective film, and it is required that the protective film in the above position does not peel off from the substrate. In terms of hardness, from the perspective of the durability of the protective film, high hardness is required. As for electrical reliability, it is required that the insulation of the protective film be maintained, or that impurities contained in the protective film do not contaminate the liquid crystal. As for transparency, it is required that the protective film does not absorb light in the visible wavelength region and does not damage the color characteristics of the color filter.

In addition to the above-mentioned requirements for the protective film, as LCD panels become more functional, wide viewing angles and high-speed responses are also required. In the process of using display methods such as in-plane switching (IPS) mode, the requirements for the protective film are becoming more stringent. In display methods such as IPS mode, if gaseous or liquid components or water generated or bleeds out from the color filter layer enters the liquid crystal layer through the protective layer, the concentration of water or ionic impurities in the liquid crystal layer increases, or bubbles are formed in the liquid crystal, which will cause poor display. Therefore, in terms of preventing the passage of the impurity components, and in terms of the fact that the gas generation from the protective film in direct contact with the liquid crystal layer is directly related to poor display, low gas generation is particularly important. In recent years, there has been a demand for thinner LCD panels, so there has been a demand for thinner protective films, and the flatness requirement for achieving flatness in thin films has also become stricter. In other words, a new issue has arisen: balancing low gas generation and flatness.

As a material for a protective film of a color filter, a large number of epoxy-based or acrylic-based compound compositions have been proposed so far (Patent Documents 1 to 5, etc.), but no material has been found that satisfies the required properties of low gas generation and flatness at the same time. [Prior Art Document] [Patent Document]

[Patent Document 1] International Publication No. 96/34303 [Patent Document 2] Japanese Patent Publication No. 2000-103937 [Patent Document 3] Japanese Patent Publication No. 2000-143772 [Patent Document 4] Japanese Patent Publication No. 2001-091732 [Patent Document 5] Japanese Patent Publication No. 2004-069930

[Problem to be solved by the invention] As described above, in a protective film for a color filter, it is necessary to highly maintain the properties required for a protective film for a color filter, such as heat resistance, chemical resistance, adhesion, hardness, electrical reliability and transparency, while satisfying the required properties of low gas generation and flatness, and the application range of the material for the protective film as a composition that can satisfy the above situation is narrowed.

Furthermore, in recent years, color filters (RGBW method) have been developed that have white (W) pixels that are not coated with color filters in addition to red, green, and blue (RGB), and the protective film is required to fill the W space that is not coated with the color composition and satisfy flatness. In other words, in addition to the existing 1 μm to 2 μm bumps on the pixels, the larger 2 μm to 3 μm concave spaces are required to be flattened using a thin film with a film thickness of 2 μm or less on the colored pixel formation portion.

The present invention is made in view of the above-mentioned problems, and aims to provide a thermosetting composition that can form a protective film that satisfies the required properties of flatness and low gas generation and is excellent in heat resistance, chemical resistance, adhesion, hardness, electrical reliability and transparency, a cured film formed by curing the composition, and a display device having the cured film. [Technical means to solve the problem]

The inventors of the present invention have conducted research to solve the problem required for a protective film of a color filter as described above, and have found that the problem can be solved by using a thermosetting composition having a specific formulation, thereby completing the present invention.

The present invention relates to (1): a thermosetting composition characterized by comprising: an epoxy compound (A) represented by the following general formula (1) wherein the average value of m is 0 to 1; an epoxy compound (B) which is liquid at room temperature; an epoxy compound (C) other than the component (A) or the component (B) having a weight average molecular weight of 900 to 20,000 and an epoxy equivalent of 150 g/eq to 500 g/eq; a curing agent (D) selected from the group consisting of polycarboxylic acids, polycarboxylic acid anhydrides, and polycarboxylic acid thermally decomposable esters; and a curing accelerator (E).

[Chemistry 1]

In the general formula (1), Ar is a divalent aromatic alkyl group having 6 to 12 carbon atoms, and a portion of the hydrogen atoms of the divalent aromatic alkyl group may be substituted with a alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or a halogen group.

In addition, the present invention relates to (2): The thermosetting composition according to (1), characterized in that: relative to the total mass of the solid components, the total content of the epoxy compound including the components (A), (B), and (C) is 55% by mass to 85% by mass, the content of the component (D) is 5% by mass to 40% by mass, and the content of the component (E) is 0.01% by mass to 2% by mass. In addition, the present invention relates to (3): The thermosetting composition according to (1) or (2), characterized in that: relative to the total mass of the solid components, the coupling agent (F) is contained in an amount of 1% by mass to 20% by mass. In addition, the present invention relates to (4): a thermosetting composition according to any one of (1) to (3), characterized in that: relative to the total mass of the epoxy compound containing components (A), (B), and (C), the content of component (A) is 5% by mass to 50% by mass, the content of component (B) is 10% by mass to 40% by mass, and the content of component (C) is 10% by mass to 70% by mass. In addition, the present invention relates to (5): a cured film, characterized in that: the thermosetting composition according to any one of (1) to (4) is cured. In addition, the present invention relates to (6): a display device, characterized in that: it has a cured film according to (5). [Effect of the Invention]

The thermosetting composition of the present invention can form a protective film that meets the required properties of flatness and low gas generation, and is also excellent in heat resistance, chemical resistance, adhesion, hardness, electrical reliability and transparency. The thermosetting composition of the present invention can be used as a protective film for color filters of LCDs including RGBW methods, and can also be used in display devices that require a transparent cured film with excellent flatness and low gas generation. That is, as a component of organic electroluminescence (EL) display devices other than LCDs, micro-light emitting diode (μLED) display devices, and display devices using quantum dots, it can be appropriately used, especially in the case of a transparent film that needs to flatten bumps or steps. Furthermore, it can also be applied to sensors such as Complementary Metal-Oxide-Semiconductor (CMOS) with color filter layers.

The present invention is described in detail below. The epoxy compound of the component (A) is an epoxy compound represented by the general formula (1) and having an average value of m of 0 to 1.

[Chemistry 2]

In the general formula (1), Ar is a divalent aromatic alkyl group having 6 to 12 carbon atoms. In addition, a part of the hydrogen atoms of the divalent aromatic alkyl group represented by Ar may be substituted with a alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or a halogen group.

The component (A) may be a bisphenol fluorene epoxy compound or a bis-naphthol fluorene epoxy compound. The component (A) has a relatively small effect on the viscosity of the thermosetting composition and is effective in imparting low gas generation or heat resistance. In particular, in order to impart low gas generation, a bis-naphthol fluorene epoxy resin is more preferably used. By optimizing the combination and the blending amount with the epoxy resins (B) and (C), even when a bisphenol fluorene epoxy resin is used, a thermosetting composition that satisfies the required properties of flatness and low gas generation of a protective film of a specific film thickness can be prepared.

The average value of m in the general formula (1) can be 0 to 1. If it is 0 or more, the solubility of the component (A) can be improved. If it exceeds 1, the curing property of the cured film tends to be insufficient. The average value of m is preferably 0.01 to 0.5, and more preferably 0.02 or more and less than 0.2. The average value of m can be calculated from the epoxide equivalent of the component (A). In the case of a bis-naphthol fluorene type epoxy compound (epoxide equivalent) × 2 = (average value of m) × 506.6 + 562.7 In the case of a bis-phenol fluorene type epoxy compound (epoxide equivalent) × 2 = (average value of m) × 406.5 + 462.5

The component (A) can be synthesized by a known method such as the method described in Japanese Patent Laid-Open No. 9-328534, and the most preferred method is to condense 9,9-bis(4-hydroxyphenyl)fluorene or 9,9-bis(4-hydroxynaphthyl)fluorene with epichlorohydrin in the presence of a base. The value of m can be set to a desired value by adjusting the molar ratio of the raw material compounds during synthesis or adjusting the reaction conditions.

The component (B) is an epoxy compound that is liquid at room temperature.

As the component (B), any chain aliphatic epoxy compound, alicyclic epoxy compound or aromatic epoxy compound may be used without particular limitation as long as it is an epoxy compound that is liquid at room temperature.

Examples of chain aliphatic epoxy compounds include trihydroxymethylpropane triglycidyl ether, trihydroxymethylethane triglycidyl ether, monoglycidyl ether or diglycidyl ether of branched alkyl esters, and more preferably, polyfunctional trihydroxymethylpropane triglycidyl ether and diglycidyl ether of branched alkyl esters. Aliphatic epoxy compounds are useful for improving heat resistance by increasing crosslinking density through reaction with a hardener. In particular, epoxy compounds having a viscosity of 30 mPa·s to 500 mPa·s (25°C) are preferably used.

Examples of the alicyclic epoxy compounds include (3',4'-epoxyepoxyhexylmethyl)3,4-epoxyepoxyhexanecarboxylate, 2-(3,4-epoxy)epoxyhexyl-5,1-spiro(3,4-epoxy)epoxyhexyl-m-dioxane or bis(3,4-epoxyepoxyhexylmethyl)adipate, hydrobisphenol A diglycidyl ether, 1,4-cyclohexanedimethanol-bis(3,4-epoxyepoxyhexanecarboxylate), and the like. Preferably, an epoxy compound having a viscosity of 50 mPa·s to 3500 mPa·s (25°C) can be used.

Examples of the aromatic epoxy compound include low molecular weight compounds such as bisphenol A type epoxy compound and bisphenol F type epoxy compound.

Among these, low molecular weight liquid compounds of (3',4'-epoxyepoxyhexylmethyl) 3,4-epoxyepoxyhexanecarboxylate and bisphenol A type epoxy resin are more preferably used.

By using these liquid epoxy resins, it is possible to provide flatness at a level that is difficult to provide using only the component (A) such as a bisphenol fluorene type or bis-naphthol fluorene type epoxy resin.

The component (C) is an epoxy compound other than the component (A) or the component (B) and has a weight average molecular weight of 900 to 20,000 and an epoxy equivalent of 150 to 500 g/eq.

As the component (C), there may be used without particular limitation, as long as the above requirements are satisfied, bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, phenol novolac type epoxy compounds, cresol novolac type epoxy compounds, glycidyl ethers of polyhydric alcohols, glycidyl esters of polyhydric carboxylic acids, 1,2-epoxy-4-(2-oxohexacyclopropyl)cyclohexane addition derivatives of 2,2-bis(hydroxymethyl)-1-butanol, The epoxy compounds include known epoxy compounds such as aliphatic epoxy compounds such as epoxides (e.g., "EHPE3150" manufactured by Daicel Corporation), copolymers of (meth)acrylates containing glycidyl (meth)acrylate as an essential component, epoxidized polybutadiene (e.g., "NISSO-PB·JP-100" manufactured by Nippon Soda Co., Ltd.), and epoxy compounds having a silicone skeleton.

The copolymer of two or more (meth)acrylates containing glycidyl (meth)acrylate as an essential component is a compound obtained by free radical copolymerization of glycidyl (meth)acrylate with (meth)acrylates and other polymerizable unsaturated compounds by a conventional method. In the free radical copolymerization, a known free radical polymerization initiator such as an azo compound or a peroxide can be used. In addition, the degree of polymerization can be controlled so that the weight average molecular weight is 900 to 20,000 by using a known chain transfer agent or polymerization inhibitor.

(Meth)acrylates other than glycidyl (meth)acrylate and other polymerizable unsaturated compounds used in the copolymer are exemplified below, but are not limited to these.

(Meth)acrylates can be obtained by condensing (meth)acrylic acid (the so-called (meth)acrylic acid refers to acrylic acid or methacrylic acid) with an alcohol (R ¹ OH) component. As the (R ¹ OH) component, a known component can be used without particular limitation. Specific examples of ^R1 include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, neopentyl, tert-pentyl, hexyl, heptyl, octyl, 2-ethylhexyl, nonyl, decyl, dodecyl, tetradecyl, hexadecyl, octadecyl, eicosyl, cyclopropyl, cyclopentyl, cyclopentylethyl, cyclohexyl, cyclohexylmethyl, 4-methylcyclohexyl, adamantyl, isobornyl, dicyclopentanyl, dicyclopentenyl, vinyl, allyl, ethynyl, phenyl, tolyl, mesityl, naphthyl, anthracenyl, phenanthryl, benzyl, 2-phenylethyl, 2-phenylvinyl and the like saturated or unsaturated monovalent hydrocarbon groups, and pyridyl, piperidinyl, etc. The saturated or unsaturated monovalent heterocyclic groups such as oxadiazole, oxadiazole, thiocyanate, thiocyanate, urea, thio ... Such a monovalent group can be appropriately selected according to the structure of the target component (C). In terms of performance and economy, a saturated or unsaturated monovalent hydrocarbon group having 1 to 20 carbon atoms is preferred, and a saturated or unsaturated monovalent hydrocarbon group having 1 to 6 carbon atoms is more preferred. The saturated or unsaturated monovalent hydrocarbon group may be a hydrocarbon group having a branched structure or a ring structure, and may be substituted with any substituent. The substituent group preferably does not have a reactive structure such as an acidic group.

As other polymerizable unsaturated compounds, styrene and its derivatives can be cited. As specific compounds, compounds obtained by introducing an alkyl group, a halogen atom, a hydroxyl group, etc. into the aromatic ring of styrene, α-methylstyrene, or p-styrene can be used.

In the component (C), in addition to the above, a polymerizable unsaturated compound containing an epoxy group other than glycidyl methacrylate (for example, glycidyl acrylate, [4-(glycidyloxy)butyl] (meth)acrylate, [(3,4-epoxycyclohexyl)methyl] (meth)acrylate, and 4-(glycidyloxymethyl)styrene, etc.), and a polymerizable unsaturated compound containing an alkoxysilyl group (for example, [3-(trimethoxysilyl)propyl] (meth)acrylate, [3-(triethoxysilyl)propyl] (meth)acrylate, and 4-(trimethoxysilyl)styrene, etc.) may be copolymerized.

Among the copolymers exemplified above, preferred examples include compounds obtained by copolymerizing glycidyl methacrylate and alkyl methacrylate (C1 to C4 alkyl), or compounds obtained by copolymerizing styrene, and having a softening point (Tg) of 10° C. to 90° C. The Tg of the copolymer is more preferably in the range of 40° C. to 90° C.

The weight average molecular weight (Mw) of the component (C) is 900 to 20,000, preferably 2,000 to 15,000, and more preferably 3,000 to 13,000. When the weight average molecular weight is greater than 20,000, the flatness of the cured film tends to decrease. In addition, it is generally difficult to control the polymerization reaction to obtain an epoxy compound having a weight average molecular weight of less than 900, so it is not easy to conceive of an epoxy compound having a weight average molecular weight of less than 900. The weight average molecular weight of the component (C) can be determined by gel permeation chromatography (GPC) (SEC (Size Exclusion Chromatography)).

The epoxy equivalent of component (C) is 150 g/eq to 500 g/eq, preferably 200 g/eq to 490 g/eq. When the epoxy equivalent is greater than 500 g/eq, the content of epoxy groups decreases and the curability is insufficient, resulting in deterioration of the properties of the cured film. In addition, the epoxy equivalent is 142 g/eq when only glycidyl methacrylate is polymerized, so epoxy compounds with an epoxy equivalent of less than 150 g/eq are difficult to conceive due to chemical structural constraints.

In order to adjust the epoxy equivalent to the above range, in component (C), the ratio of the repeating units derived from glycidyl methacrylate in the total number of the repeating units derived from the polymerizable unsaturated compound constituting component (C) is preferably 50 mol% or more, more preferably 65 mol% or more. The ratio of the repeating units derived from glycidyl methacrylate is generally reflected in the molar ratio of the polymerizable unsaturated compound used as a raw material when synthesizing component (C).

The thermosetting composition of the present invention may also contain an epoxy compound that is not equivalent to the components (A) to (C). Examples of such epoxy compounds include: a trifunctional epoxy compound having a triazine skeleton (TEPIC series manufactured by Nissan Chemical Co., Ltd.) that is solid at room temperature and has an epoxy equivalent outside the range of the component (C), an epoxy compound that is waxy or granular at room temperature and has a low melting point, namely, an ε-caprolactam-modified product of (3',4'-epoxyepoxyhexylmethyl) 3,4-epoxyepoxyhexanecarboxylate (TTA2081, TTA2083 manufactured by Tetrachem Co., Ltd.), and the like. Furthermore, in the TEPIC series or TTA series, if an epoxy compound having properties within the range of the (B) component and the (C) component is developed, it can of course be used as the (B) component and the (C) component.

The component (D) is a curing agent selected from the group consisting of polycarboxylic acids, anhydrides of polycarboxylic acids, and thermally decomposable esters of polycarboxylic acids.

Polycarboxylic acids are compounds having two or more carboxyl groups in one molecule, and examples thereof include succinic acid, maleic acid, cyclohexane-1,2-dicarboxylic acid, cyclohexene-1,2-dicarboxylic acid, cyclohexene-4,5-dicarboxylic acid, norbornane-2,3-dicarboxylic acid, phthalic acid, benzene-1,2,4-tricarboxylic acid, cyclohexane-1,2,4-tricarboxylic acid, benzene-1,2,4,5-tetracarboxylic acid, cyclohexane-1,2,4,5-tetracarboxylic acid, and butane-1,2,3,4-tetracarboxylic acid.

As the anhydride of the polycarboxylic acid, the anhydrides of the polycarboxylic acids exemplified above can be mentioned, and they may be intermolecular anhydrides, and generally, an anhydride that is ring-closed within the molecule is used. As a preferred anhydride, trimellitic anhydride can be exemplified.

Examples of the thermally decomposable esters of polycarboxylic acids include tert-butyl esters, 1-(alkyloxy)ethyl esters, and 1-(alkylthio)ethyl esters of the polycarboxylic acids exemplified above (wherein the alkyl group described herein is a saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms, and the hydrocarbon group may have a branched structure or a ring structure and may be substituted with any substituent).

In addition, as component (D), a polymer or copolymer having two or more carboxyl groups may be used. The carboxyl groups of the polymer or copolymer may be an anhydride or a thermally decomposable ester. Examples of such polymers or copolymers include polymers or copolymers containing (meth)acrylic acid as a constituent component, copolymers containing maleic anhydride as a constituent component, compounds obtained by reacting tetracarboxylic dianhydride with diamine or diol and ring-opening the anhydride, and the like.

Component (E) is a hardening accelerator.

As the component (E), a known compound known as a curing accelerator, a curing catalyst or a latent curing agent for epoxy compounds can be used. Examples of the component (E) include tertiary amines, quaternary ammonium salts, tertiary phosphines, quaternary phosphonium salts, boric acid esters, Lewis acids, organometallic compounds, and imidazoles, and particularly preferred are 1,8-diazabicyclo[5.4.0]undec-7-ene or 1,5-diazabicyclo[4.3.0]non-5-ene or salts thereof.

Component (F) is a coupling agent.

As the component (F), a silane coupling agent (3-(glycidyloxy)propyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, 3-ureidopropyltriethoxysilane, etc.), a titanium-based coupling agent, an aluminum-based coupling agent, etc. can be used.

The thermosetting composition of the present invention may contain a solvent (G). The solvent may be a known compound, for example, an ester solvent (butyl acetate, cyclohexyl acetate, etc.), a ketone solvent (methyl isobutyl ketone, cyclohexanone, etc.), an ether solvent (diethylene glycol dimethyl ether, diethylene glycol ethyl methyl ether, etc.), an alcohol solvent (3-methoxybutanol, ethylene glycol mono-tert-butyl ether, etc.), an aromatic solvent (toluene, xylene, etc.), an aliphatic solvent, an amine solvent, and an amide solvent may be used without particular limitation. From the aspect of safety, ester or ether solvents having a propylene glycol skeleton are preferred, such as propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol dimethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, and propylene glycol diacetate, etc. In addition, 3-methoxybutyl acetate, 3-methoxy-3-methylbutyl acetate, and 1,3-butanediol diacetate, etc., which have structures similar to these, are also preferred.

There is no particular restriction on the solid content concentration of the thermosetting composition. For use as a protective film for a color filter, the total amount of components other than the solvent, i.e., the solid content concentration, is generally adjusted to a range of 10% to 30% by mass. In addition, in order to improve the flatness of the protective film for the color filter, it is preferred to control the drying property of the thermosetting composition by using 40% to 90% by mass of a solvent having a boiling point of less than 150°C at normal pressure and 10% to 60% by mass of a solvent having a boiling point of 150°C or more at normal pressure.

The thermosetting composition of the present invention preferably has a total content (A+B+C) of 55% to 85% by mass, more preferably 60% to 80% by mass, of the epoxy compound including the components (A), (B), and (C) relative to the total mass of the solid components. If (A+B+C) is less than 55% by mass, the ratio of the curing agent to (A+B+C) becomes large, and the properties of the cured epoxy compound cannot be fully obtained, or the excess cured epoxy that is not useful for the curing reaction has an adverse effect on the gas generation property. On the other hand, if (A+B+C) exceeds 85 mass %, the ratio of the hardener to (A+B+C) becomes extremely small, the hardening reaction does not fully advance, and the heat resistance of the hardened material becomes insufficient. In particular, when the (B) component is excessive, the adverse effect on the gas generation property also becomes greater.

The thermosetting composition of the present invention preferably has a content of component (A) of 5% to 50% by mass, more preferably 10% to 50% by mass, relative to the total mass of the epoxy compound. In addition, the thermosetting composition of the present invention preferably has a content of component (B) of 10% to 40% by mass, more preferably 20% to 40% by mass, relative to the total mass of the epoxy compound. In addition, the thermosetting composition of the present invention preferably has a content of component (C) of 10% to 70% by mass, more preferably 10% to 50% by mass, relative to the total mass of the epoxy compound.

The thermosetting composition of the present invention preferably has a content of component (D) of 5% to 40% by mass, more preferably 10% to 30% by mass, relative to the total mass of the solid components. If the content of component (D) is less than 5% by mass, the curing reaction is not sufficiently advanced, and the heat resistance of the cured product is insufficient, and the physical properties of the cured product cannot be fully obtained. In addition, especially when component (B) is excessive, the adverse effect on gas generation becomes greater. If the content of component (D) exceeds 40% by mass, the excess cured product that is useless for the curing reaction has an adverse effect on gas generation, and the characteristics as a cured product cannot be fully obtained.

In the thermosetting composition of the present invention, from the viewpoint of ensuring the transparency of the cured film and achieving a balance between the effect of accelerating the curing and the storage stability, the content of the component (E) relative to the total mass of the solid components is preferably 0.01 mass% to 2 mass%, and more preferably 0.05 mass% to 1.5 mass%. If the component (E) is less than 0.01 mass%, it lacks the effect as an accelerator and it is difficult to obtain a cured product with sufficient physical properties. In addition, if the component (E) exceeds 2 mass%, sufficient storage stability cannot be obtained when preparing the thermosetting composition solution, or it has an adverse effect on coloring during heating.

The thermosetting composition of the present invention can be used with the content of the component (F) set to 1 mass% to 20 mass% relative to the total mass of the solid components. If the component (F) is less than 1 mass%, there is a tendency for insufficient adhesion to the applied lower layer. If it exceeds 20 mass%, the excess component (F) that is useless for adhesion will deteriorate the gas generation. When used as a protective film for a color filter, when the lower layer is an organic layer such as an RGB pixel, it is preferably 1 mass% to 10 mass%. When it is in direct contact with a glass substrate as in the RGBW method, when adhesion to layers other than the organic layer also becomes a problem, it is preferably 5 mass% to 20 mass%. Independent of the underlying species, the more preferred range is 5 mass % to 15 mass %.

The thermosetting composition of the present invention may also contain other arbitrary components as needed, for example, it may contain coloring materials, fillers, resins, additives, etc. Here, the coloring materials may include dyes, organic pigments, inorganic pigments, carbon black pigments, etc., the fillers may include silica, talc, etc., the resins may include vinyl resins, polyester resins, polyamide resins, polyimide resins, polyurethane resins, polyether resins, melamine resins, etc., and the additives may include crosslinking agents, dispersants, surfactants, silane coupling agents, viscosity adjusters, wetting agents, defoaming agents, antioxidants, ultraviolet absorbers, etc. As these arbitrary components, known compounds may be used without particular limitation. When used as a protective film for a color filter, a surfactant (fluorine-based surfactant, silicone-based surfactant, etc.) can be used, but the total content thereof is preferably set to an upper limit of 10 mass % in the solid component of the thermosetting composition.

The method for preparing the cured product of the thermosetting composition of the present invention can utilize a known method. For example, after applying or injecting the thermosetting composition into an appropriate substrate or mold corresponding to the purpose or use, the solvent is removed and cured by heating. The solvent can also be removed by reduced pressure drying, etc.

The cured product of the thermosetting composition of the present invention can be made into a film-like cured film. The cured film is applied to the surface of the pixel coloring composition applied on the substrate of the color filter and cured to produce a protective film for the color filter. At this time, when producing a color filter having white (W) pixels without a color filter applied with a pixel coloring composition in addition to RGB, if the thermosetting composition of the present invention is applied and cured to produce a protective film, the W space with a depth of about 1.0 μm to 3.0 μm formed due to the non-application of the coloring composition can be filled, and the flatness between the surface of the protective film formed on the RGB coloring composition applied on the substrate and the surface of the protective film formed on the W space can be satisfied.

The cured product of the thermosetting composition of the present invention can be used as a protective film for color filters of LCDs including RGBW systems, and can also be used in display devices that require a transparent cured film with excellent flatness and low gas generation. That is, it can be used as a component of organic EL display devices other than LCDs, μLED display devices, and display devices using quantum dots, especially in the case of a transparent film that needs to flatten unevenness or steps. Furthermore, it can also be used in sensors such as CMOS equipped with a color filter layer. In addition, the cured product of the thermosetting composition of the present invention can fill the step portion as described above and improve the flatness of the surface, so it can also be used in anti-corrosion agent layers such as solder resist layers, anti-plating layers, anti-corrosion layers, inter-layer insulation layers such as multi-layer printed wiring boards, gas barrier films, sealing materials for lenses and semiconductor light-emitting elements such as light-emitting diodes (LEDs), top coatings of coatings or inks, plastic hard coatings, metal anti-corrosion films, etc. In addition, it can be used not only as a coating agent, but also the thermosetting composition itself can be formed and applied to the production of films, substrates, plastic parts, optical lenses, etc., so it is extremely useful. [Example]

Hereinafter, embodiments of the present invention will be specifically described based on embodiments and comparative examples, but the present invention is not limited to these.

[Synthesis Example 1] 451 parts by mass of 9,9-bis(4-hydroxynaphthyl)fluorene and 555 parts by mass of epichlorohydrin were added to a reaction vessel equipped with a stirring device, a condenser, and an oil-water separation tube capable of performing a decompression reaction. After complete dissolution, the system was depressurized to 20 kPa and 73°C, and then 129.2 parts by mass of a 49% NaOH aqueous solution was added dropwise over 3 hours. The reaction was carried out under reflux, and the refluxed water was separated from the epichlorohydrin by an oil-water separation tube, and the epichlorohydrin was returned to the reaction vessel, and the water was removed to the outside of the system for reaction. After the reaction was completed, the epichlorohydrin was distilled off and dissolved in 600 parts by mass of toluene. The salt generated thereafter was removed, and after washing with water, 36.5 parts by mass of a 49% NaOH solution and 14.5 parts by mass of water were added, and the mixture was heated and stirred at 80°C for 3 hours for purification. After purification, the salt and other impurities were washed repeatedly. Toluene was recovered from the washed toluene solution to obtain 380 parts by mass of an epoxy compound (epoxy compound (A)-1). The epoxy equivalent of the obtained resin was 296 g/eq.

[Synthesis Example 2] In Synthesis Example 1, except that 350 parts by mass of 9,9-bis(4-hydroxyphenyl)fluorene was used instead of 451 parts by mass of 9,9-bis(4-hydroxynaphthyl)fluorene, the same reaction and purification were carried out as in Synthesis Example 1 to obtain epoxide compound (A)-2. The epoxy equivalent of the obtained resin was 257 g/eq.

(Preparation of a thermosetting composition) Prepare a thermosetting composition by mixing according to the compositions shown in Tables 1 to 5, stirring and mixing at room temperature for 3 hours, and dissolving the solid components in a solvent. The composition is recorded as parts by mass, with the total of the solid components being 100 parts by mass. Some solid components are synthesized in a state of being initially dissolved in a solvent (propylene glycol monomethyl ether acetate). In such cases, the composition values represent parts by mass as solid components, and the carried solvent components are recorded as being included in the parts by mass of the solvent. The components used in the preparation of the embodiments are shown below.

(Component (A): Epoxy compound represented by the general formula (1)) (A)-1: Bis-naphthol fluorene-type epoxy compound prepared in Synthesis Example 1, wherein the average value of m in the general formula (1) is 0.06 (A)-2: Bis-phenol fluorene-type epoxy compound prepared in Synthesis Example 2, wherein the average value of m in the general formula (1) is 0.12

(Component (B): Epoxide compound that is liquid at room temperature) (B)-1: (3',4'-Epoxyepoxyhexylmethyl) 3,4-epoxyepoxyhexanecarboxylate (Celloxide 2021P manufactured by Daicel Corporation, epoxide equivalent 135) (B)-2: Bisphenol A type epoxide compound (JER828 manufactured by Mitsubishi Chemical, epoxide equivalent 190)

(Component (C): an epoxy compound having a weight average molecular weight of 900 to 20,000 and an epoxy equivalent of 150 g/eq to 500 g/eq) (C)-1: 1,2-epoxy-4-(2-oxohexopropyl)cyclohexane adduct of 2,2-bis(hydroxymethyl)-1-butanol (manufactured by Daicel Co., Ltd., EHPE3150, Mw: about 1,400, epoxy equivalent: 170 g/eq to 190 g/eq) (C)-2: Glycidyl methacrylate copolymer having a copolymer composition of glycidyl methacrylate: methyl methacrylate: n-butyl methacrylate = 5:3:2 (Mw: about 9,000, epoxy equivalent: 295 g/eq) (C)-3: Bisphenol A type epoxy resin (manufactured by Mitsubishi Chemical Co., Ltd., JER1001, Mw: about 900, epoxy equivalent: 450 g/eq to 500 g/eq)

(Component (D): Hardener) (D): Trimellitic anhydride

(Component (E): hardening accelerator) (E): 1,8-diazabicyclo[5.4.0]undec-7-ene octanoate

(Component (F): coupling agent) (F): 3-(glycidyloxy)propyltrimethoxysilane

(Component (G): solvent) (G)-1: Propylene glycol monomethyl ether acetate (G)-2: Methyl 3-methoxypropionate (G)-3: Diethylene glycol ethyl methyl ether

(Ingredients (S): Other ingredients) (S): Fluorine-based surfactant (manufactured by DIC Corporation, Megafac F-556)

[Table 1]

[Table 2]

[Table 3]

[Table 4]

[Table 5]

(Evaluation of thermosetting composition: flatness) As a color filter substrate, a substrate having a black matrix and red, green, and blue pixels and a mosaic-like pattern without blue pixels and having 2.5 μm-high concave and convex surfaces on the pixels was prepared. The thermosetting composition was applied to the color filter substrate using a spin coater and dried for 2 minutes using a 90°C heating plate to prepare a test piece. At this time, the coating conditions (rotational rotation speed) were adjusted in such a way that a cured film with a film thickness of 1.5 μm was obtained on the pixels. Next, the test piece was calcined in a hot air oven at 230°C for 30 minutes to obtain a cured film of the thermosetting composition.

The height of the unevenness at two points selected arbitrarily on the surface of the cured film formed in a pixel-protecting manner was measured using a contact surface roughness meter (trade name: Fine Shape Tester ET-4000A, manufactured by Kosaka Laboratory Co., Ltd.), and a three-stage evaluation was performed based on the following criteria. ◎ (Good): The height difference of the unevenness was 0.10 μm or less ○ (Slightly Good): The height difference of the unevenness exceeded 0.10 μm and was 0.15 μm or less △ (Slightly Poor): The height difference of the unevenness exceeded 0.15 μm and was 0.20 μm or less × (Poor): The height difference of the unevenness exceeded 0.2 μm

(Evaluation of thermosetting composition: gas generation) The thermosetting composition was applied on an alkali-free glass substrate using a spin coater and dried for 2 minutes using a 90°C heating plate to prepare a test piece. At this time, the coating conditions (rotation speed) were adjusted so that a cured film with a film thickness of 1.5 μm was obtained. Next, the test piece was calcined in a hot air oven at 230°C for 30 minutes to obtain a cured film of the thermosetting composition. 10 mg of the cured film of the test piece was cut and sampled, and the temperature was raised from room temperature to 120°C at 10°C/min under atmospheric air flow and maintained at 120°C for 30 minutes. The temperature was then raised from 120°C to 230°C at 10°C/min and maintained at 230°C for 3 hours. The weight loss at this time was measured using a thermogravimetric analyzer (trade name: Rigaku Co., Ltd. differential thermal balance Thermo plus EVO2) and evaluated in three stages based on the following criteria. ◎: Weight loss less than 5% ○: Weight loss of 5% or more and less than 7% △: Weight loss of 7% or more and less than 10% ×: Weight loss of 10% or more

(Evaluation of thermosetting composition: Chemical resistance) Test pieces with cured films formed of thermosetting compositions were prepared in the same manner as the evaluation of gas generation. The test pieces were immersed in N-methylpyrrolidone at 40°C for 30 minutes, and the state of the cured films was observed. The three-stage evaluation was performed based on the following criteria. ○: No change in appearance and the film thickness change was within 2% △: No change in appearance, but the film thickness change exceeded 2% ×: Changes in appearance were observed

(Evaluation of thermosetting composition: Adhesion) Test pieces with cured films formed of thermosetting compositions were prepared in the same manner as the evaluation of gas generation. After the test pieces were kept in an environment of 121°C and 100% humidity for 5 hours using an environmental testing machine, the cured films were subjected to a cross-cut tape peeling test and evaluated in six stages from 5B to 0B according to the American Society for Testing and Materials (ASTM) D3359 standard.

(Evaluation of thermosetting compositions: electrical reliability) Test pieces with cured films formed of thermosetting compositions were prepared in the same manner as the gas generation evaluation. 40 mg of the cured film of the test piece was cut and sampled, and the sample was immersed in 1 g of liquid crystal ("MLC-6608" manufactured by Merck) and kept at 100°C for 72 hours. The voltage retention rate of the liquid crystal was measured and evaluated in three stages based on the following criteria. ○: Voltage retention rate is 95% or more △: Voltage retention rate is 90% or more and less than 95% ×: Voltage retention rate is less than 90%

(Evaluation of Thermosetting Composition: Transparency) Test pieces with cured films formed of thermosetting compositions were prepared in the same manner as the evaluation of gas generation. The transmittance of the cured films at a wavelength of 400 nm was measured using a spectrophotometer and evaluated in three stages based on the following criteria. ○: Transmittance is 95% or more △: Transmittance is 93% or more and less than 95% ×: Transmittance is less than 93%

The evaluation results of each thermosetting composition are shown in Tables 6 to 10.

[Table 6]

[Table 7]

[Table 8]

[Table 9]

[Table 10]

According to the results of Examples 1 to 18 and Comparative Examples 21 to 32, it is known that the thermosetting composition of each example satisfies the flatness, heat resistance, adhesion and hardness required of the protective film of the color filter, and further has excellent chemical resistance, electrical reliability and transparency.

without

without

Claims (4)

A thermosetting composition comprising: an epoxy compound (A) represented by the following general formula (1) wherein the average value of m is 0 to 1; an epoxy compound (B) which is liquid at room temperature; an epoxy compound (C) other than the epoxy compound (A) or the epoxy compound (B) having a weight average molecular weight of 900 to 20,000 and an epoxy equivalent of 200 g/eq to 490 g/eq; a curing agent (D) selected from the group consisting of polycarboxylic acids, polycarboxylic acid anhydrides, and polycarboxylic acid thermally decomposable esters; a curing accelerator (E); and a solvent (G); wherein the total amount of the components other than the solvent (G), i.e., the solid content concentration, is 10% to 30% by mass relative to the solid content. The total mass of the epoxy compound comprising the epoxy compound (A), the epoxy compound (B), and the epoxy compound (C) is 55 mass% to 85 mass%, the content of the hardener (D) is 5 mass% to 40 mass%, and the content of the hardening accelerator (E) is 0.01 mass% to 2 mass%. Relative to the total mass of the epoxy compound comprising the epoxy compound (A), the epoxy compound (B), and the epoxy compound (C), the content of the epoxy compound (A) is 5 mass% to 50 mass%, the content of the epoxy compound (B) is 10 mass% to 40 mass%, and the content of the epoxy compound (C) is 10 mass% to 70 mass%.

In the general formula (1), Ar is a divalent aromatic alkyl group having 6 to 12 carbon atoms, and a portion of the hydrogen atoms of the divalent aromatic alkyl group may be substituted by a alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or a halogen group. The thermosetting composition as described in Item 1 of the patent application contains 1% to 20% by mass of a coupling agent (F) relative to the total mass of the solid component. A cured film, characterized in that it is formed by curing the thermosetting composition as described in item 1 or item 2 of the patent application scope. A display device, characterized in that it has a hardened film as described in item 3 of the patent application scope.