WO2013032190A1

WO2013032190A1 - Photopolymerizable unsaturated resin, photosensitive resin composition comprising the same, and light shielding spacer and liquid crystal display device formed therefrom

Info

Publication number: WO2013032190A1
Application number: PCT/KR2012/006802
Authority: WO
Inventors: Gyung-Sik Choi; Sun Ryu; Kyung-Jae Park; Cheon-Sun PARK; Hag-Ju Lee; Hyeon-Jin YUN
Original assignee: Rohm And Haas Electronic Materials Korea Ltd.
Priority date: 2011-08-26
Filing date: 2012-08-24
Publication date: 2013-03-07
Also published as: KR101349622B1; KR20130022955A; JP6093766B2; TW201326244A; CN110007562A; TWI477526B; JP2014529652A; CN103890659A

Abstract

The present invention relates to a photopolymerizable unsaturated resin, a photosensitive resin composition comprising said photopolymerizable unsaturated resin, a functional monomer having at least one ethylenically unsaturated bond, a polymerization initiator, a black organic pigment and a solvent. The photosensitive resin composition is useful for preparing a light shielding spacer having low dielectric constant and excellent light shielding property, resolution and elastic recovery ratio.

Description

PHOTOPOLYMERIZABLE UNSATURATED RESIN, PHOTOSENSITIVE RESIN COMPOSITION COMPRISING THE SAME, AND LIGHT SHIELDING SPACER AND LIQUID CRYSTAL DISPLAY DEVICE FORMED THEREFROM

The present invention relates to a novel photopolymerizable unsaturated resin, a photosensitive resin composition comprising the same, and a light shielding spacer and a liquid crystal display device formed therefrom.

A liquid crystal display (LCD) device, as one type of flat panel display devices, which are currently widely being used, comprises a thin film transistor (TFT) substrate on which pixel electrodes are formed; a color filter substrate on which a common electrode is formed and which faces the TFT substrate; and a liquid crystal layer inserted between the TFT substrate and the color filter substrate. Such an LCD device displays images in a manner of controlling the amount of light transmitting the liquid crystal layer by applying a voltage to the pixel electrodes and common electrode and rearranging the liquid crystal molecules of the liquid crystal layer.

Displays which maximize space utilization and are easily portable by having low power consumption, a light weight and thin thickness, and high screen quality have been required as consumption patterns become more diversified. Accordingly, various attempts to further reduce the thickness of the displays have been carried out. As one effort, a technology for directly forming a color filter layer in a TFT structure have been suggested, instead of the conventional technique of separately fabricating a TFT lower substrate and a colored upper substrate, and then laminating the substrates.

In the new technology for directly forming a color filter layer in the TFT structure, a spacer is formed from a photosensitive composition by generally using lithography. The spacer should have light-shielding properties in order to prevent malfunction of a TFT as a switching device caused by incident light. In order to prepare such a light-shielding spacer, it has been suggested that carbon black be mixed with a photosensitive resin composition. However, when preparing a spacer from a photosensitive resin composition comprising carbon black, there is a problem that an electrical distortion phenomenon is generated by an electrical field applied to the upper and lower substrates, due to the high dielectric constant of carbon black. Therefore, it is required to develop a spacer that has excellent light-shielding properties and a low dielectric constant.

Further, a photosensitive resin composition used in the preparation of a light-shielding spacer is generally a black composition prepared by mixing dyes having different colors or various types of dyes, wherein said dyes do not easily dissolve in a developing solution. Due to the low solubility in the developing solution, the dyes have problems that developing properties are not good, a long time is consumed in development, or a desired degree of resolution is not obtained. In particular, the importance of resolution is further increased in the case of forming colored independent dot spacer patterns.

Further, since a height difference should exist between a main spacer and a sub-spacer in the spacer, exposure energy should be controlled so that the height of the completed spacer according to locations should be in a certain ratio, and the spacer should also possess some physical properties, such as elastic recovery ratio, in order to maintain resistance to pressure on the upper substrate.

Korean Patent Application Laid-Open No. 2010-0066197 discloses a black photosensitive resin composition, which has good pattern formability, and exhibits high compression displacement and a high recovery rate, as well as a low dielectric constant and superior optical density when forming a thin film. However, said document does not take the resolution of a thin film formed from the composition into consideration, and regards a recovery rate of 70% as being proper, which does not satisfy the level of the recovery rate required by the relevant industry.

Japanese Patent Application Laid-Open No. 2002-040440 discloses a radiation-sensitive composition, which is capable of forming a spacer having excellent light-shielding properties and high mechanical strength and heat resistance, which is not deformed irreversibly during the sealing of panels, and which does not generate display defects due to a gap difference in liquid crystal layers. However, the document does not take dielectric constant or resolution into consideration in a spacer formed from the composition.

[Prior Art Documents]

[Patent Documents]

(Patent Document 1) Korean Patent Application Laid-Open No. 2010-0066197

(Patent Document 2) Japanese Patent Application Laid-Open No. 2002-040440

The first aspect of the present invention provides a photopolymerizable unsaturated resin of a novel structure to be included in a photosensitive resin composition.

The second aspect of the present invention provides a photosensitive resin composition which includes the novel photopolymerizable unsaturated resin, which can form dot spacer patterns of a size of 10 to 100 μm due to sufficient solubility in developing solutions before and after light exposure, and which is capable of maintaining excellent light-shielding properties while lowering the dielectric constant of the formed dot spacer patterns.

The third aspect of the present invention provides a light shielding spacer, which is formed from the photosensitive resin composition, and which has sufficient resolution and excellent elastic recovery ratio.

The fourth aspect of the present invention provides a liquid crystal display device having the light shielding spacer.

According to an aspect of the present invention, there is provided a photopolymerizable unsaturated resin which is a product (P1) obtained by reacting an epoxy resin(A) represented by formula I with an unsaturated basic acid (B) to form an epoxy adduct (AB), and reacting said adduct with a polybasic acid anhydride (C); or which is a product (P2) obtained by reacting an epoxy resin (A) represented by formula I with an unsaturated basic acid (B) to form an epoxy adduct (AB), reacting said adduct with a polybasic acid anhydride (C) to form a product (P1), and further reacting said product (P1) with a monofunctional or polyfunctional epoxy compound (D).

[Formula I]

wherein the carbon labeled with * is replaced with a carbon labeled with * in one selected from the groupconsisting of

,

and

;

L¹ is C_1-10 alkylene, C_3-20 cycloalkylene or C_1-10 alkyleneoxy;

R¹, R², R³, R⁴, R⁵, R⁶ and R⁷ are the same or different and are each independently selected from the group consisting of hydrogen, C_1-10alkyl, C_1-10 alkoxy, C_2-10 alkenyl and C_6-14 aryl;

R⁸ is selected from the group consisting of hydrogen, C_1-10 alkyl which is unsubstituted or substituted by halogen or hydroxy, C_2-10 alkenyl and C_6-14 aryl; and

n is an integer of from 0 to 10.

According to another aspect of the present invention, there is provided a photosensitive resin composition comprising the photopolymerizable unsaturated resin; a functional monomer having at least one ethylenically unsaturated bond; a polymerization initiator; a black organic pigment; and a solvent.

According to a further aspect of the present invention, there is provided a light shielding spacer formed from the photosensitive resin composition.

According to a still further aspect of the present invention, there is provided a liquid crystal display device having the spacer.

A photosensitive resin composition comprising a photopolymerizable unsaturated resin according to the present invention can form a light shielding spacer with dot spacer patterns of a size of 10 to 100 μm due to sufficient solubility in developing solutions before or after light exposure. Further, the formed light shielding spacer has a low dielectric constant of 8 or less, is excellent in light-shielding property by having an optical density per μm of 1.0 or more, and has sufficient resolution and excellent elastic recovery ratio.

Hereinafter, preferred embodiments of the present invention will be described in detail so that a person having ordinary skill in the art can easily carry out the invention.

1. Photopolymerizable unsaturated resin

The photopolymerizable unsaturated resin which is a product (P1) obtained by the steps of reacting an epoxy resin(A) represented by formula I with an unsaturated basic acid (B) to form an epoxy adduct (AB), and reacting said adduct with a polybasic acid anhydride (C), or a product (P2) obtained by further reacting a monofunctional or polyfunctional epoxy compound (D) with the product (P1).

The epoxy adduct (AB) can be obtained by reacting the epoxy resin (A) corresponding to 1 equivalent of an epoxy group with the unsaturated basic acid (B) corresponding to 0.1 to 5 equivalents, preferably 0.2 to 2 equivalents, and more preferably 0.4 to 1 equivalent of a carboxyl group according to known addition reactions.

The photopolymerizable unsaturated resin is a product (P1) obtained by reacting the epoxy adduct (AB) corresponding to 1 equivalent of a hydroxyl group with the polybasic acid anhydride (C) corresponding to 0.1 to 5 equivalents, preferably 0.2 to 2 equivalents, and more preferably 0.4 to 1 equivalent of an acid anhydride group. The photopolymerizable unsaturated resin can be obtained by reacting the epoxy adduct (AB) with the polybasic acid anhydride (C) according to known esterification reactions.

Further, the photopolymerizable unsaturated resin can be obtained by additionally esterifying a monofunctional or polyfunctional epoxy compound (D) with the product (P1) in an amount of 0.1 to 5 equivalents, preferably 0.2 to 2 equivalents and more preferably 0.3 to 1 equivalent of the epoxy group in the monofunctional or polyfunctional epoxy compound with respect to 1 equivalent of the hydroxyl group of the epoxy adduct (AB).

The esterification between the monofunctional or polyfunctional epoxy compound (D) and a product (P1) obtained by esterifying the epoxy adduct (AB) with the polybasic acid anhydride (C) can occur between a carboxyl group derived from the polybasic acid anhydride (C) and an epoxy group of the monofunctional or polyfunctional epoxy compound (D).

Further, in order to efficiently proceed with a reaction between a carboxyl group derived from the polybasic acid anhydride (C) and an epoxy group of the monofunctional or polyfunctional epoxy compound (D), the photopolymerizable unsaturated resin can be prepared by (i) reacting the epoxy adduct (AB) corresponding to 1 equivalent of a hydroxyl group with the polybasic acid anhydride (C) in such an amount that the sum of an acid anhydride equivalent of the polybasic acid anhydride (C) and an epoxy equivalent in the monofunctional or polyfunctional epoxy compound (D) is not less than 1.0 equivalent, preferably 1.1 to 2.0 equivalents to produce a product, and (ii) further reacting the product with the monofunctional or polyfunctional epoxy compound (D).

The photopolymerizable unsaturated binder resin has a weight average molecular weight (Mw) preferably ranging from 1,500 to 20,000, more preferably from 3,000 to 15,000. If a weight average molecular weight of the photopolymerizable unsaturated resin is within the above-mentioned range, handling property and pattern formability are good since the flowability of the resin is maintained within a proper range.

A photosensitive resin composition according to the present invention may include 0.5 to 50 wt% of a photopolymerizable unsaturated binder resin with respect to the total weight of the photosensitive resin composition except the residual amount of solvent. If the content of the photopolymerizable unsaturated binder resin is within the above-mentioned range, a pattern is easily formed after light exposure and developing processes, the basic physical properties of a light shielding material are satisfied, processing time, such as developing time, and sensitivity are optimized, and characteristics such as compressive properties, chemical resistance and the like are improved.

(A) Epoxy resin

Epoxy resin (A) used in the present invention is a compound represented by the following formula 1 having a 9H-xanthene skeleton.

The 9H-xanthene skeleton structure of the epoxy resin (A) functions as a factor that improves adhesion between a cured body and a substrate, alkali resistance, formability, strength and the like, and increases the resolution of micro-patterns when developing and eliminating non-cured portions.

[Formula I]

wherein the carbon labeled with * is replaced with a carbon labeled with * in one selected from the group consisting of

,

and

;

L¹ is a C_1-10 alkylene group, a C_3-20 cycloalkylene group or a C_1-10 alkyleneoxy group;

R¹ to R⁷ are the same as or different from one another and are each independently a hydrogen atom, a C_1-10 alkyl group, a C_1-10 alkoxy group, a C_2-10 alkenyl group or a C_6-14 aryl group;

R⁸ is selected from the group consisting of a hydrogen atom, an ethyl group, CH₃CHCl-, CH₃CHOH-, CH₂=CHCH₂- and a phenyl group; and

n is an integer of from 0 to 10.

Specific examples of the C_1-10 alkylene group may include a methylene group, an ethylene group, a propylene group, an isopropylene group, a butylene group, an isobutylene group, a sec-butylene group, a tert-butylene group, a pentylene group, an isopentylene group, a tert-pentylene group, a hexylene group, a heptylene group, an octylene group, an isooctylene group, a tert-octylene group, a 2-ethylhexylene group, a nonylene group, an isononylene group, a decylene group, and an isodecylene group.

Specific examples of the C_3-20 cycloalkylene group may include a cyclopropylene group, a cyclobutylene group, a cyclopentylene group, a cyclohexylene group, a cycloheptylene group, a decalinylene group, and an adamantylene group.

Specific examples of the C_1-10 alkyleneoxy group may include a methyleneoxy group, an ethyleneoxy group, a propyleneoxy group, a butyleneoxy group, a sec-butyleneoxy group, a tert-butyleneoxy group, a pentyleneoxy group, a hexyleneoxy group, a heptyleneoxy group, an octyleneoxy group, and a 2-ethyl-hexyleneoxy group.

Specific examples of the C_1-10 alkyl group may include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, an isopentyl group, a tert-pentyl group, a hexyl group, a heptyl group, an octyl group, an isooctyl group, a tert-octyl group, a 2-ethylhexyl group, a nonyl group, an isononyl group, a decyl group, and an isodecyl group.

Specific examples of the C_1-10 alkoxy group may include a methoxy group, an ethoxy group, a propyloxy group, a butyloxy group, a sec-butoxy group, a tert-butoxy group, a pentoxy group, a hexyloxy group, a heptoxy group, an octyloxy group, and a 2-ethyl-hexyloxy group.

Specific examples of the C_2-10 alkenyl group may include a vinyl group, an allyl group, a butenyl group, and a propenyl group.

Specific examples of the C_6-14 aryl group may include a phenyl group, a tolyl group, a xylyl group, and a naphthyl group.

(B) Unsaturated basic acid

An unsaturated basic acid (B) used in the present invention is used in order to improve the sensitivity of a photosensitive resin composition comprising a photopolymerizable unsaturated resin according to the present invention. Specific examples of the unsaturated basic acid (B) may include acrylic acid, methacrylic acid, crotonic acid, cinnamic acid, sorbic acid, hydroxyethyl methacrylate·malate, hydroxyethyl acrylate·malate, hydroxypropyl methacrylate·malate, hydroxypropyl acrylate·malate, dicyclopentadiene·malate, and polyfunctional (meth)acrylate having a carboxyl group and two or more (meth)acryloyl groups, but not limited thereto. The unsaturated basic acids can be used alone or in combinations of two or more thereof. Acrylic acid, methacrylic acid, and polyfunctional (meth)acrylate having a carboxyl group and two or more (meth)acryloyl groups are preferably used as the unsaturated basic acids.

The polyfunctional (meth)acrylate having a carboxyl group and two or more (meth)acryloyl groups can be obtained by reacting, e.g., a dibasic acid anhydride or carbonic acid with a polyfunctional (meth)acrylate having a hydroxyl group and two or more (meth)acryloyl groups in a molecule.

(C) Polybasic acid anhydride

A polybasic acid anhydride (C) used in the present invention is used in order to improve pattern formability, developing properties and developing rate by increasing the acid value of a photosensitive resin composition comprising a photopolymerizable unsaturated resin according to the present invention.

Examples of the polybasic acid anhydride (C) may include one or more selected from the group consisting of succinic anhydride, maleic anhydride, trimellitic anhydride, pyromellitic anhydride, 2,2'-3,3'-benzophenone tetra carboxylic dianhydride, 3,3'-4,4'-benzophenone tetra carboxylic dianhydride, ethylene glycol bis(anhydrotrimellitate), glycerol tris(anhydrotrimellitate), phthalic anhydride, hexahydrophthalic anhydride, methyl hydrophthalic anhydride, tetrahydrophthalic anhydride, nadic anhydride, methyl nadic anhydride, trialkyl tetrahydrophthalic anhydride, hexahydrophthalic anhydride, 5-(2,5-dioxotetrahydrofuryl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, an adduct of trialkyl tetrahydrophthalic anhydride-maleic anhydride, dodecenyl succinic anhydride and methyl himic anhydride, preferably selected from the group consisting of succinic anhydride, trimellitic anhydride, and hexahydrophthalic anhydride, but are not limited thereto.

(D) Monofunctional or polyfunctional epoxy compound

A monofunctional epoxy compound used in the present invention is used in order to further improve the developing property of a photosensitive resin composition by controlling the acid value of the photopolymerizable unsaturated resin. Preferably, the solid contents of a photosensitive resin composition according to the present invention have an acid value ranging from 20 to 120 mg KOH/g. Thus, the amount of a monofunctional epoxy compound is preferably selected to satisfy the above acid value.

Specific examples of the monofunctional epoxy compound may include glycidyl methacrylate, methyl glycidyl ether, ethyl glycidyl ether, propyl glycidyl ether, isopropyl glycidyl ether, butyl glycidyl ether, isobutyl glycidyl ether, t-butyl glycidyl ether, pentyl glycidyl ether, hexyl glycidyl ether, heptyl glycidyl ether, octyl glycidyl ether, nonyl glycidyl ether, decyl glycidyl ether, undecyl glycidyl ether, dodecyl glycidyl ether, tridecyl glycidyl ether, tetradecyl glycidyl ether, pentadecyl glycidyl ether, hexadecyl glycidyl ether, 2-ethylhexyl glycidyl ether, allyl glycidyl ether, propargyl glycidyl ether, 2-methoxyethyl glycidyl ether, phenyl glycidyl ether, p-methoxyphenyl glycidyl ether, p-butylphenyl glycidyl ether, cresyl glycidyl ether, 2-methylcresyl glycidyl ether, 4-nonylphenyl glycidyl ether, benzyl glycidyl ether, p-cumylphenyl glycidyl ether, trityl glycidyl ether, 2,3-epoxypropyl methacrylate, epoxylated soybean oil, epoxylated linseed oil, glycidyl butyrate, vinylcyclohexane monoxide, 1,2-epoxy-4-vinylcyclohexane, styrene oxide, pinene oxide, methylstyrene oxide, cyclohexene oxide and propylene oxide.

Polyfunctional epoxy compounds used in the present invention play a role of controlling a developing rate by increasing the molecular weight of the photopolymerizable unsaturated resin.

Examples of the polyfunctional epoxy compounds may include polyglycidyl ether of polyvalent alcohol or its alkyleneoxide adduct, polyglycidyl ether of polybasic acid, cyclohexene oxide- or cyclopentene oxide-containing compounds obtained by epoxidating cyclohexene- or cyclopentene-containing compounds with an oxidizer. More specifically, the examples of the polyfunctional epoxy compounds may include: alkylidene bisphenol polyglycidyl ether type epoxy resins such as bisphenol A type epoxy resin, bisphenol B type epoxy resin, bisphenol C type epoxy resin, bisphenol E type epoxy resin, bisphenol F type epoxy resin, bisphenol M type epoxy resin, bisphenol P type epoxy resin, bisphenol S type epoxy resin, and bisphenol Z type epoxy resin; water-added bisphenol type diglycidyl ethers obtained by adding water to the alkylidene bisphenol polyglycidyl ether type epoxy resins; glycidyl ethers of aliphatic polyvalent alcohol such as ethyleneglycol diglycidyl ether, 1,3-propyleneglycol diglycidyl ether, 1,2-propyleneglycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, 1,8-octanediol diglycidyl ether, 1,10-decanediol diglycidyl ether, 2,2-dimethyl-1,3-propanediol diglycidyl ether, diethyleneglycol diglycidyl ether, triethyleneglycol diglycidyl ether, tetraethyleneglycol diglycidyl ether, hexaethyleneglycol diglycidyl ether, 1,4-cyclohexanedimethanol diglycidyl ether, 1,1-tri(glycidyloxymethyl)propane, 1,1,1-tri(glycidyloxymethyl)ethane, 1,1,1-tri(glycidyloxymethyl)methane, 1,1,1,1-tetra(glycidyloxymethyl)methane, glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, sorbitol tetraglycidyl ether, and dipentaerythrithol hexaglycidyl ether; polyglycidyl ethers of polyetherpolyol, which are obtained by adding two or more alkylene oxides to polyvalent alcohols such as propylene glycol, trimethylol propane, and glycerin; novolac type epoxy compounds such as phenol novolac type epoxy compound, biphenyl novolac type epoxy compound, cresol novolac type epoxy compound, bisphenol A novolac type epoxy compound, and dicyclopentadiene Novolac type epoxy compound; alicyclic epoxy compounds such as 3,4-epoxy-3-methylcyclohexylmethyl-3,4-epoxy-3-methylcyclohexane carboxylate, 3,4-epoxy-5-methylcyclohexylmethyl-3,4-epoxy-5-methylcyclohexane carboxylate, 3,4-epoxy-6-methylcyclohexylmethyl-3,4-epoxy-6-methylcyclohexane carboxylate, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate, 1-epoxyethyl-3,4-epoxycyclohexane, bis(3,4-epoxycyclohexylmethyl)adipate, methylenebis(3,4-epoxycyclohexane), isopropylidenebis(3,4-epoxycyclohexane), dicyclopentadiene diepoxide, ethylenebis(3,4-epoxycyclohexane carboxylate), and 1,2-epoxy-2-epoxyethylcyclohexane; glycidyl esters of dibasic acids such as phthalic acid diglycidyl ester, tetrahydrophthalic acid diglycidyl ester, and dimer acid glycidyl ester; glycidyl amines such as tetraglycidyl diaminodiphenyl methane, triglycidyl P-aminophenol, and N,N-diglycidyl aniline; heterocyclic epoxy compounds such as 1,3-diglycidyl-5,5-dimethyl hydantoin and triglycidyl isocyanurate; dioxide compounds such as dicyclopentadiene dioxide; naphthalene type epoxy compounds; triphenyl methane type epoxy compounds; and dicyclopentadiene type epoxy compounds.

Commercially available products as the polyfunctional epoxy compounds may include, for example, BREN-S, EPPN-201, EPPN-501N, EOCN-1020, GAN, and GOT (Nippon Kayaku Co., Ltd.); Adeka Resin EP-4000, Adeka Resin EP-4003S, Adeka Resin EP-4080, Adeka Resin EP-4085, Adeka Resin EP-4088, Adeka Resin EP-4100, Adeka Resin EP-4900, Adeka Resin ED-505, Adeka Resin ED-506, Adeka Resin KRM-2110, Adeka Resin KRM-2199, and Adeka Resin KRM-2720 (Adeka Corporation); R-508, R-531, and R-710 (Mitsui Chemicals); Epicoat 190P, Epicoat 191P, Epicoat 604, Epicoat 801, Epicoat 825, Epicoat 871, Epicoat 872, Epicoat 1031, Epicoat RXE15, Epicoat YX-4000, Epicoat YDE-205, and Epicoat YDE-305(Japan Epoxy Resins Co., Ltd.); Sumiepoxy ELM-120 and Sumiepoxy ELM-434(Sumitomo Chemical Co., Ltd.); Denacoal EM-150, Denacoal EX-201, Denacoal EX-211, Denacoal EX-212, Denacoal EX-313, Denacoal EX-314, Denacoal EX-322, Denacoal EX-411, Denacoal EX-421, Denacoal EX-512, Denacoal EX-521, Denacoal EX-614, Denacoal EX-711, Denacoal EX-721, Denacoal EX-731, Denacoal EX-811, Denacoal EX-821, Denacoal EX-850, Denacoal EX-851, and Denacoal EX-911(Nagase Chemtex Corporation); Epolite 70P, Epolite 200P, Epolite 400P, Epolite 40E, Epolite 100E, Epolite 200E, Epolite 400E, Epolite 80MF, Epolite 100MF, Epolite 1500NP, Epolite 1600, Epolite 3002, Epolite 4000, Epolite FR-1500, Epolite M-1230, and Epolite EHDG-L (Kyoeisha Chemical Co., Ltd.); SB-20 (Okamura Oil Mill Ltd.); Epicron 720(Dainippon Ink and Chemicals, Incorporated); UVR-6100, UVR-6105, UVR-6110, UVR-6200, and UVR-6228 (Union Carbide Corporation); Celoxide 2000, Celoxide 2021, Celoxide 2021P, Celoxide 2081, Celoxide 2083, Celoxide 2085, Celoxide 3000, Cycomer A200, Cycomer Ml00, Cycomer Ml0l, Epolead GT-301, Epolead GT-302, Epolead 401, Epolead 403, Epolead HD300, EHPE-3150, ETHB, and Epoblend (Daicel Chemical Industries Ltd.); PY-306, 0163, and DY-022 (Ciba Specialty Chemicals Corporation); Suntohto ST0000, Epotohto YD-011, Epotohto YD-115, Epotohto YD-127, Epotohto YD-134, Epotohto YD-172, Epotohto YD-6020, Epotohto YD-716, Epotohto YD-7011R, Epotohto YD-901, Epotohto YDPN-638, Epotohto YH-300, Neotohto PG-202, and Neotohto PG-207 (Tohto Kaisei Co., Ltd.); and Blenmer G, etc. (NOF Corporation)

2. Functional monomer having at least one ethylenically unsaturated bond

The functional monomer having at least one ethylenically unsaturated bond is a reactive unsaturated compound and is a monomer or oligomer generally used in a photosensitive resin composition, and monofunctional or polyfunctional esters of acrylic acid or methacrylic acid having at least one ethylenically unsaturated double bond could be used.

The content of the functional monomer having at least one ethylenically unsaturated bond may be 1 to 50% by weight with respect to the total weight of the photosensitive resin composition excluding the residual amount of solvent. If the content of the functional monomer having at least one ethylenically unsaturated bond is within the above-mentioned range, patterns are formed easily, and it is beneficial in the development margin aspect since overdevelopment of a bottom part is not generated during the developing process.

The functional monomer having at least one ethylenically unsaturated bond is a reactive unsaturated compound, and examples of the functional monomer having at least one ethylenically unsaturated bond may include at least one selected from the group consisting of ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, triethylene glycol dimethacrylate, 1,6-hexanediol diacrylate, pentaerythritol triacrylate, dipentaerythritol pentacrylate, dipentaerythritol hexacrylate, bisphenol A epoxyacrylate, ethylene glycol monomethylether acrylate, ethylene glycol dimethacrylate and 1,6-hexanediol dimethacrylate, but not limited thereto.

Examples of commercially available functional monomers having at least one ethylenically unsaturated bond may include the following products: Aronix M-101, Aronix M-111 and Aronix M-114 (Toagosei Co., Ltd.); KAYARAD TC-110S and KAYARAD TC-120S (Nippon Kayaku Co. Ltd.); and V-158 and V-2311 (Osaka Yuki Kagaku Kogyo Kabushiki Kaisha) as commercial products of monofunctional (meth)acrylate;

Aronix M-210, Aronix M-240 and Aronix M-6200 (Toagosei Co., Ltd.); KAYARAD HDDA, KAYARAD HX-220 and KAYARAD R-604 (Nippon Kayaku Co. Ltd.); and V260, V312 and V335 HP (Osaka Yuki Kagaku Kogyo Kabushiki Kaisha) as commercial products of bifunctional (meth)acrylate products; and

Aronix M-309, Aronix M-400, Aronix M-405, Aronix M-450, Aronix M-7100, Aronix M-8030 and Aronix M-8060 (Toagosei Co., Ltd.); KAYARAD TMPTA, KAYARAD DPCA-20, KAYARAD DPCA-30, KAYARAD DPCA-60 and KAYARAD DPCA-120 (Nippon Kayaku Co. Ltd.); and V-295, V-300, V-360, V-GPT, V-3PA and V-400 (Osaka Yuki Kagaku Kogyo Kabushiki Kaisha) as commercial products of tri- or higher functional (meth)acrylate products. The foregoing compounds can be used alone or in a combination of two or more thereof.

The content of the functional monomer having at least one ethylenically unsaturated bond is ranged from 1 to 50% by weight, preferably from 1 to 20% by weight, and more preferably from 1 to 15% by weight with respect to the total photosensitive resin composition excluding a residual amount of solvent. If the content of the functional monomer having at least one ethylenically unsaturated bond is within the above-mentioned range of 1 to 50% by weight, sensitivity is improved in the presence of oxygen, patterns are formed easily, compatibility with copolymers is improved, the coat surface is not roughened after the formation of a coat, and it is beneficial in the development margin aspect since overdevelopment of a bottom part is not generated during the development.

3. Polymerization initiator

A polymerization initiator in the present invention is a compound which generates active species that are capable of initiating the polymerization of the functional monomer having at least one ethylenically unsaturated bond, or the monofunctional or polyfunctional epoxy compound when exposed to radiation light such as visible rays, ultraviolet rays, far ultraviolet rays, electron rays, and X-rays.

Examples of such photopolymerization initiator may include acetophenone-based compounds, biimidazole-based compounds, triazine-based compounds, ο-acyloxime based compounds, onium salt-based compounds, benzoin-based compounds, benzophenone-based compounds, dikenone-based compounds, α-diketone based compounds, polynuclear quinone-based compounds, thioxanthone-based compounds, diazo-based compounds, imidesulfonate-based compounds, oxime-based compounds, carbazole-based compounds, and sulfonium borate-based compounds. These compounds are components that generate active radicals, active acids, or both the active radicals and active acids by light exposure, and they may be used alone or in a mixture of two or more thereof.

Examples of the acetophenone-based compounds may include 2,2’-diethoxyacetophenone, 2,2’-dibutoxyacetophenone, 2-hydroxy-2-methylpropiophenone, p-t-butyltrichloroacetophenone, p-t-butyldichloroacetophenone, 4-chloroacetophenone, 2,2’-dichloro-4-phenoxyacetophenone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, and 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one.

Examples of the benzophenone-based compounds may include benzophenone, benzoyl benzoate, methyl benzoyl benzoate, 4-phenyl benzophenone, hydroxy benzophenone, acrylized benzophenone, 4,4’-bis(dimethylamino)benzophenone, 4,4’-bis(diethylamino)benzophenone, 4,4’-dimethylaminobenzophenone, 4,4’-dichlorobenzophenone, and 3,3’-dimethyl-2-methoxybenzophenone.

Examples of the thioxanthone-based compounds may include thioxanthone, 2-crolthioxanthone, 2-methylthioxanthone, isopropyl thioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, and 2-chlorothioxanthone.

Examples of the benzoin-based compounds may include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, and benzyl dimethyl ketal.

Examples of the triazine-based compounds may include 2,4,6-trichloro-s-triazine, 2-phenyl-4,6-bis(trichloromethyl)-s-triazine, 2-(3’4’-dimethoxystyryl)-4,6-bis(trichloromethyl)-s-triazine, 2-(4’-methoxynaphthyl)-4,6-bis(trichloromethyl)-s-triazine, 2-(p-methoxyphenyl)-4,6-bis(trichloromethyl)-s-triazine, 2-(p-tolyl)-4,6-bis(trichloromethyl)-s-triazine, 2-biphenyl 4,6-bis(trichloromethyl)-s-triazine, bis(trichloromethyl)-6-styryl-s-triazine, 2-(naphtho 1-yl)-4,6-bis(trichloromethyl)-s-triazine, 2-(4-methoxynaphtho 1-yl)-4,6-bis(trichloromethyl)-s-triazine, 2-4-trichloromethyl(piperonyl)-6-triazine, and 2-4-trichloromethyl(4’-methoxystyryl)-6-triazine.

Preferably, examples of the polymerization initiator may include one or more selected from the group consisting of p-dimethylaminoacetophenone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, benzyldimethylketal, benzophenone, benzoin propyl ether, diethyl thioxanthone, 2,4-bis(trichloromethyl)-6-p-methoxyphenyl-s-triazine, 2-trichloromethyl-5-styryl-1,3,4-oxodiazole, 9-phenyl acridine, 3-methyl-5-amino-((s-triazine-2-yl)amino)-3-phenylcoumarin, 2-(o-chlorophenyl)-4,5-diphenyl imidazolyl dimer, 1-phenyl-1,2-propanedione-2-(o-ethoxycarbonyl)oxime, o-benzoyl-4'-(benzmercapto)benzoyl-hexyl-ketoxime, 2,4,6-trimethylcarbonyl-diphenylphosphonyloxide, hexafluorophosphoro-trialkylphenylsulfonium salt, 2-mercapto benzimidazole, 2,2'-benzothiazolyl disulfide, and mixtures thereof, but not limited thereto.

The content of the polymerization initiator may be 0.1 to 10% by weight with respect to the total weight of the photosensitive resin composition excluding the residual amount of solvent. If the content of the polymerization initiator is within the above-mentioned range, patterns of a colored layer are easily obtained and the formed colored layer is sufficiently adhered to the substrate during the development since curing due to exposure to light is sufficiently performed.

4. Black organic pigment

The black organic pigment means an organic pigment that has been colorized into black to represent black that is similar to carbon black that is an inorganic pigment.

Examples of the black organic pigment may include, but are not limited to, at least one selected from aniline black, lactam black and perylene black.

Further, the photosensitive resin composition according to the present invention may additionally include a black inorganic pigment along with the black organic pigment, wherein the black inorganic pigment is one or more selected from the group consisting of carbon black, chromium oxide, iron oxide, and titanium black, and its content is from 0.1 to 70 parts by weight with respect to 100 parts by weight of the black organic pigment.

If the content of the inorganic pigment is increased, the melt flow phenomenon deteriorates, and thus it is difficult to form patterns on a thick film, such as a column spacer. Therefore, it is important to control a mixing ratio of the organic pigment to the inorganic pigment.

The content of the black organic pigment or both the black organic pigment and the black inorganic pigment may be 10 to 60% by weight with respect to the total weight of the photosensitive resin composition excluding the residual amount of solvent. If the content of the black inorganic pigment is within the above-mentioned range, the optical density is prevented from being too low, and processability, such as developing properties, is improved and high optical densities is achieved.

Meanwhile, a dispersant may be used to disperse a pigment in the photosensitive resin composition according to the present invention. The dispersant may be used by adding it to the pigment, for example, by treating the surface of the pigment with the dispersant in advance, or the dispersant may be used by directly adding it along with the pigment when preparing the photosensitive resin composition.

5. Solvent

A solvent used in the present invention has compatibility with the components of the above-mentioned photosensitive resin composition, but does not react with the components.

Examples of the solvent may include compounds comprising: alcohols, such as methanol and ethanol; ethers, such as dichloroethyl ether, n-butyl ether, diisoamyl ether, methylphenyl ether, and tetrahydrofuran; glycol ethers, such as ethylene glycol monomethyl ether, and ethylene glycol monoethyl ether; cellosolve acetates, such as methylcellosolve acetate, ethylcellosolve acetate, and diethylcellosolve acetate; carbitols, such as methylethyl carbitol, diethyl carbitol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol methylethyl ether, and diethylene glycol diethyl ether; propylene glycol alkylether acetates, such as propylene glycol methyl ether acetate, and propylene glycol propyl ether acetate; aromatic hydrocarbons, such as toluene, and xylene; ketones, such as methylethylketone, cyclohexanone, 4-hydroxy-4-methyl-2-pentanone, methyl-n-propylketone, methyl-n-butylketone, methyl-n-amylketone, and 2-heptanone; saturated aliphatic monocarboxylate alkyl esters, such as ethyl acetate, n-butyl acetate, and isobutyl acetate; lactate esters, such as methyl lactate, and ethyl lactate; alkyl oxyacetate esters, such as methyl oxyacetate, ethyl oxyacetate, and butyl oxyacetate; alkyl alkoxyacetate esters, such as methyl methoxyacetate, ethyl methoxyacetate, butyl methoxyacetate, methyl ethoxyacetate, and ethyl ethoxyacetate; 3-oxypropionate alkylesters, such as methyl 3-oxypropionate, and ethyl 3-oxypropionate; alkyl 3-alkoxypropionate esters, such as methyl 3-methoxypropionate, ethyl 3-methoxypropionate, ethyl 3-ethoxypropionate, and methyl 3-ethoxypropionate; alkyl 2-oxypropionate esters, such as methyl 2-oxypropionate, ethyl 2-oxypropionate, and propyl 2-oxypropionate; alkyl 2-alkoxypropionate esters, such as methyl 2-methoxypropionate, ethyl 2-methoxypropionate, ethyl 2-ethoxypropionate, and methyl 2-ethoxypropionate; alkyl monooxy monocarboxylate esters including 2-oxy-2-methylpropionate esters, such as methyl 2-oxy-2-methylpropionate and ethyl 2-oxy-2-methylpropionate, and 2-alkoxy-2-methylpropionate alkyls, such as methyl 2-methoxy-2-methylpropionate and ethyl 2-ethoxy-2-methylpropionate; esters, such as ethyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl hydroxylacetate, and methyl 2-hydroxy-3-methylbutyrate; and ketonate esters, such as ethyl pyruvate. The examples of the solvent may additionally include high-boiling point solvents, such as N-methylformamide, N,N-dimethylformamide, N-methylformanilide, N-methylacetamide, N,N-dimethylacetamide, N-methylpyrrolidone, dimethylsulfoxide, benzylethyl ether, dihexyl ether, acetonylacetone, isophorone, capronic acid, caprylic acid, 1-octanol, 1-nonanol, benzyl alcohol, benzyl acetate, ethyl benzoate, diethyl oxalate, diethyl maleate, γ-butyrolactone, ethylene carbonate, propylene carbonate, and phenylcellosolve acetate.

In view of the compatibility and reactivity of the solvent with other components of the resin composition of the present invention, preferable examples of the solvent among the above-mentioned examples may include: glycol esters, such as ethylene glycol monomethyl ether; ethylene glycol alkylether acetates, such as ethyl cellosolve acetate; esters, such as ethyl 2-hydroxy propionate; diethylene glycols, such as diethylene glycol monomethyl ether; and propylene glycol alkylether acetates, such as propylene glycol methylether acetate, and propylene glycol propylether acetate.

The solvent is used in a residual amount and preferably contained in an amount of 50 to 90% by weight with respect to the total content 100% by weight of a photosensitive resin composition comprising the solvent. When the content of the solvent is from 50 to 90% by weight, the resin composition has an appropriate viscosity and processability is improved.

6. Other additives

1) Silane coupling agent

A photosensitive resin composition of the present invention may further comprise a silane coupling agent having one or more reactive substituents selected from the group consisting of a carboxyl group, a methacryloyl group, an isocyanate group, an epoxy group, and combinations thereof in order to improve adhesive properties to the substrate.

Specific examples of the silane coupling agent may include trimethoxysilyl benzoic acid, γ-methacryloxypropyl trimethoxysilane, vinyl triacetoxysilane, vinyl trimethoxysilane, γ-isocyanatepropyl triethoxysilane, γ-glycidoxy propyl trimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and they can be used alone or in combination of two or more thereof.

If the silane coupling agent is added, the addition amount of the silane coupling agent is preferably 0.001 to 20 parts by weight with respect to 100 parts by weight of a photopolymerizable binder resin.

2) Surfactant

A photosensitive resin composition of the present invention may additionally include a surfactant, if necessary, in order to improve coatability and prevent the formation of defects.

Examples of the surfactant may include fluorine-based surfactants commercialized under the names of: BM-1000 and BM-1100 (BM Chemie); Megaface F142D, F172, F173 and F183 (Dainippon Ink & Chemicals, Inc.); Fluorad FC-135, FC-170C, FC-430 and FC-431 (Sumitomo 3M Co., Ltd.); Surflon S-112, S-113, S-131, S-141 and S-145 (Asahi Glass Co., Ltd.); and SH-28PA, SH-190, SH-193, SZ-6032 and SF-8428 (Toray Dow Corning Silicone).

If the surfactant is added, the addition amount of the surfactant is preferably 0.001 to 5 parts by weight with respect to 100 parts by weight of the photopolymerizable binder resin.

In addition, the photosensitive resin composition of the present invention may include other additives such as an antioxidant and a stabilizer in certain amounts which do not deteriorate physical properties of the composition.

According to another aspect of the present invention, the present invention provides a light shielding spacer formed from the photosensitive resin composition. The spacer is characterized in that it has a dielectric constant of 8 F/m or less and an optical density of 1.0 or more.

According to still another aspect of the present invention, the present invention provides a liquid crystal display device comprising the spacer.

Hereinafter, the present invention will be described in more detail with reference to the following examples as preferred embodiments.

[Examples]

Synthesis Example 1. Epoxy resin synthesis (xanthene derivative [a-1])

After mixing 125.4 g of spiro(fluorene-9,9’-xanthene)-3’,6’-diol with 0.1386 g of t-butylammonium bromide in a 3,000 ml three-neck round-bottom flask, and injecting 78.6 g of epichlorohydrin into the three-neck round-bottom flask, the mixture was reacted by heating the mixture to 90°C. If spiro(fluorene-9,9’-xanthene)-3’,6’-diol was completely removed through liquid chromatography analysis, 3 equivalents of an aqueous 50% NaOH solution were slowly added to the cooled reactant after cooling the reactant to 30°C. Thereafter, if epichlorohydrin was completely removed through liquid chromatography analysis, the mixture was extracted with dichloromethane, and was washed with water three times. The resulting organic layer was dried with magnesium sulfate and subjected to vacuum distillation to remove dichloromethane, and was recrystallized using a mixture of dichloromethane and methanol at a mixing ratio of 50 vol%:50 vol% to produce an epoxy compound.

After mixing an equivalent of the synthesized epoxy compound with 0.004 equivalent of t-butylammonium bromide, 0.001 equivalent of 2,6-diisobutylphenol, and 2.2 equivalents of acrylic acid, the mixture was further mixed with 8.29 g of propylene glycol monomethyl ether acetate as a solvent to form a reaction solution. The reactants were dissolved by heating the reaction solution to a temperature range of 90 to 100°C while blowing air into the reaction solution at a flow rate of 25 ml/min. The reactants were dissolved completely by heating the reaction solution to 120°C when the reaction solution was in the white turbidity state. The solution was stirred until the solution had an acid value of less than 1.0 mg KOH/g by measuring an acid value of the solution when the solution became transparent and had a high viscosity. It required 11 hours to reach the target acid value of 0.8. After completion of the reaction, the temperature of the reactor was lowered to a room temperature to produce a colorless transparent solid.

Synthesis Example 2. Epoxy resin synthesis (xanthene derivative [a-2])

After mixing 125.4 g of 9,9-diphenyl-9H-xanthene-3,6-diol with 0.1386 g of t-butylammonium bromide in a 3,000 ml three-neck round-bottom flask, and injecting 78.6 g of epichlorohydrin into the three-neck round-bottom flask, the mixture was reacted by heating the mixture to 90°C. If 9,9-diphenyl-9H-xanthene-3,6-diol was completely removed through liquid chromatography analysis, 3 equivalents of an aqueous 50% NaOH solution were slowly added to the cooled reactant after cooling the reactant to 30°C. Thereafter, if epichlorohydrin was completely removed through liquid chromatography analysis, the mixture was extracted with dichloromethane, and was washed with water three times. The resulting organic layer was dried with magnesium sulfate and subjected to vacuum distillation to remove dichloromethane, and was recrystallized using a mixture of dichloromethane and methanol at a mixing ratio of 50 vol%:50 vol% to produce an epoxy compound.

After mixing an equivalent of the synthesized epoxy compound with 0.004 equivalent of t-butylammonium bromide, 0.001 equivalent of 2,6-diisobutylphenol, and 2.2 equivalents of acrylic acid, the mixture was further mixed with 8.29 g of propylene glycol monomethyl ether acetate as a solvent to form a reaction solution. The reactants were dissolved by heating the reaction solution to a temperature range of 90 to 100°C while blowing air into the reaction solution at a flow rate of 25 ml/min. The reactants were dissolved completely by heating the reaction solution to 120°C when the reaction solution was in the white turbidity state. The solution was stirred until the solution had an acid value of less than 1.0 mg KOH/g by measuring an acid value of the solution if the solution became transparent and had a high viscosity. It required 11 hours to reach the target acid value of 0.8. After the completion of the reaction, the temperature of the reactor was lowered to a room temperature to produce a colorless transparent solid.

Synthesis Example 3. Epoxy resin synthesis (xanthene derivative [a-3])

After mixing 145.2 g of 3,6-dimethoxyspiro(fluorene-9,9’-xanthene)-3’,6’-diol with 0.1423 g of t-butylammonium bromide in a 3,000 ml three-neck round-bottom flask, and injecting 73.6 g of epichlorohydrin into the three-neck round-bottom flask, the mixture was reacted by heating the mixture to 90°C. If 3,6-dimethoxyspiro(fluorene-9,9’-xanthene)-3’,6’-diol was completely removed through liquid chromatography analysis, 3 equivalents of an aqueous 50% NaOH solution were slowly added to the cooled reactant after cooling the reactant to 30°C. Thereafter, if epichlorohydrin was completely removed through liquid chromatography analysis, the mixture was extracted with dichloromethane, and was washed with water three times. The resulting organic layer was dried with magnesium sulfate and subjected to vacuum distillation to remove dichloromethane, and was recrystallized using a mixture of dichloromethane and methanol at a mixing ratio of 50 vol%:50 vol% to form an epoxy compound.

After mixing an equivalent of the synthesized epoxy compound with 0.004 equivalent of t-butylammonium bromide, 0.001 equivalent of 2,6-diisobutylphenol, and 2.2 equivalents of acrylic acid, the mixture was mixed with 8.29 g of propylene glycol monomethyl ether acetate as a solvent to form a reaction solution. The reactants were dissolved by heating the reaction solution to a temperature range of 90 to 100°C while blowing air into the reaction solution at a flow rate of 25 ml/min. The reactants were dissolved completely by heating the reaction solution to 120°C when the reaction solution was in the white turbidity state. The solution was stirred until the solution had an acid value of less than 1.0 mg KOH/g by measuring an acid value of the solution if the solution became transparent and had a high viscosity. It required 11 hours to reach the target acid value of 0.8. After the completion of the reaction, the temperature of the reactor was lowered to a room temperature to produce a colorless transparent solid.

Preparation Example 1. Preparation of photopolymerizable unsaturated resin

The materials were stirred at 120°C for 13 hours after injecting 43 g of a polymerizable compound obtained in the synthesis example 1 (hereinafter, referred to as “compound a-1”), 33.6 g of acrylic acid (hereinafter, referred to as “compound b-1”), 0.04 g of 2,6-di-tert-butyl-p-cresol, 0.21 g of tetrabutyl ammonium acetate, and 18 g of propylene glycol-1-monomethyl ether-2-acetate into a reaction flask. After cooling the mixture to room temperature and adding 24 g of propylene glycol-1-monomethyl ether-2-acetate and 10 g of succinic anhydride (hereinafter, referred to as “compound c-1”) to the cooled mixture, the mixture was stirred at 100°C for 3 hours. After additionally adding 8 g of bisphenol Z glycidyl ether (hereinafter, referred to as “compound d-2”) to the mixture, and sequentially stirring the materials at 120°C for 4 hours, at 90°C for 3 hours, at 60°C for 2 hours, and at 40°C for 5 hours, the mixture was reprecipitated in water and alcohol to obtain a powder-shaped target material, a photopolymerizable unsaturated resin having alkali developing properties. The obtained resin had a weight average molecular weight of 5,500 and an acid value of 105 mg KOH/g.

The reaction product was obtained by addition-reacting compound b-1 that is component (B) with compound a-1 that is component (A) to form an epoxy adduct (AB), and esterifying the epoxy adduct (AB) with compound c-1 that is component (C) in an amount of 0.8 parts by equivalent with respect to 1 part by equivalent of a hydroxyl group of the epoxy adduct (AB), and then additionally esterifying the resulting product with compound d-2 that is component (D) in an amount of 0.3 parts by equivalent of an epoxy group of the compound d-2 with respect to 1 part by equivalent of a hydroxyl group of the epoxy adduct (AB).

Further, the epoxy adduct (AB) has a structure to which a carboxyl group of compound b-1 is added at a ratio of 1.0 with respect to an epoxy group of compound a-1.

Preparation Example 2. Preparation of photopolymerizable unsaturated resin

The materials were stirred at 120°C for 16 hours after injecting 16.95 g of a polymerizable compound obtained in the synthesis example 2 (hereinafter referred to as “compound a-2”), 4.43 g of acrylic acid (compound b-1), 6 g of 2,6-di-tert-butyl-p-cresol, 0.11 g of tetrabutyl ammonium acetate, and 14.25 g of propylene glycol-1-monomethyl ether-2-acetate into a reaction flask. After cooling the mixture to room temperature and adding 9.31 g of propylene glycol-1-monomethyl ether-2-acetate, 7.41 g of hexahydrophthalic anhydride (hereinafter referred to as “compound c-2”) and 0.25 g of tetra-n-butylammonium acetate to the cooled mixture, the mixture was stirred at 70°C for 4 hours and reprecipitated in water and alcohol to obtain a powder-shaped target material, a photopolymerizable unsaturated resin having alkali developing properties. The obtained resin had a weight average molecular weight of 4,500 and an acid value of 110 mg KOH/g.

The reaction product was obtained by addition-reacting compound b-1 that is component (B) with compound a-2 that is component (A) to form an epoxy adduct (AB), and esterifying the epoxy adduct (AB) with compound c-2 that is component (C) in an amount of 0.8 parts by equivalent with respect to 1 part by equivalent of a hydroxyl group of the epoxy adduct (AB).

Further, the epoxy adduct (AB) has a structure to which a carboxyl group of compound b-1 is added at a ratio of 1.0 with respect to an epoxy group of compound a-2.

Preparation Example 3. Preparation of photopolymerizable unsaturated resin

The materials were stirred at 120°C for 16 hours after injecting 16.95 g of a polymerizable compound obtained in Synthesis Example 3 (hereinafter referred to as “compound a-3”), 4.43 g of acrylic acid (compound b-1), 6 g of 2,6-di-tert-butyl-p-cresol, 0.11 g of tetrabutyl ammonium acetate, and 14.25 g of propylene glycol-1-monomethyl ether-2-acetate into a reaction flask. After cooling the mixture to room temperature and adding 9.31 g of propylene glycol-1-monomethyl ether-2-acetate, 7.41 g of hexahydrophthalic anhydride (compound c-2) and 0.25 g of tetra-n-butylammonium acetate to the cooled mixture, the mixture was stirred at 70°C for 4 hours and reprecipitated in water and alcohol to obtain a powder-shaped target material, a photopolymerizable unsaturated resin having alkali developing properties. The obtained resin had a weight average molecular weight of 3,500 and an acid value of 105 mg KOH/g.

The reaction product was obtained by addition-reacting compound b-1 that is component (B) with compound a-3 that is component (A) to form an epoxy adduct (AB), and esterifying the epoxy adduct (AB) with compound c-2 that is component (C) in an amount of 0.8 parts by equivalent with respect to 1 part by equivalent of a hydroxyl group of the epoxy adduct (AB).

Preparation Example 4. Preparation of a black organic pigment composition

After mixing organic black (Black 582 as lactam black produced by Ciba-Geigy Corporation), a dispersant, and a polymer for dispersion at a ratio of 50 parts by weight, 8 parts by weight and 8 parts by weight, respectively, based on the solid content, propylene glycol monomethyl ether acetate (PGMEA) as a solvent was added to the mixture such that the resulting mixture had a solid concentration of 25% by weight. The total weight of the dispersion was 50 g, which was stirred by a stirrer to pre-mix the materials. The mixture was subjected to dispersion treatment by a paint shaker at a temperature of 25 to 60°C for 6 hours. Zirconia beads having a diameter of 0.3 mm were used as beads, and were added to the mixture in the same weight as the dispersion. A black pigment composition was prepared by separating the beads from the dispersion by a filter after finishing the dispersion.

Preparation Example 5. Preparation of a composition of black organic pigment and inorganic pigment

A pigment composition was prepared using the same method as in Preparation Example 4, except that 35 parts by weight of lactam black and 15 parts by weight of carbon black produced by Degussa were used, instead of 50 parts by weight of lactam black in Preparation Example 4.

Preparation Example 6. Preparation of a composition of black organic pigment and inorganic pigment

A pigment composition was prepared using the same method as in Preparation Example 4, except that 30 parts by weight of lactam black and 20 parts by weight of carbon black produced by Degussa were used, instead of 50 parts by weight of lactam black in Preparation Example 4.

Preparation Example 7. Preparation of a composition of black organic pigment and inorganic pigment

A pigment composition was prepared using the same method as in Preparation Example 4, except that 25 parts by weight of lactam black and 25 parts by weight of carbon black produced by Degussa were used, instead of 50 parts by weight of lactam black in Preparation Example 4.

Preparation Example 8. Preparation of a composition of black organic pigment and inorganic pigment

A pigment composition was prepared using the same method as in Preparation Example 4, except that 15 parts by weight of lactam black and 35 parts by weight of carbon black produced by Degussa were used, instead of 50 parts by weight of lactam black in Preparation Example 4.

Preparation Example 9. Preparation of a composition of black inorganic pigment

A pigment composition was prepared in the same method as in Preparation Example 4 except that 50 parts by weight of carbon black produced by Degussa were used instead of 50 parts by weight of lactam black in the Preparation Example 4.

Example 1

A photosensitive resin composition having black alkali developing properties was obtained by well stirring 1.0874 g of a photopolymerizable unsaturated resin obtained in Preparation Example 1, 0.7249 g of dipentaerythritol hexaacrylate, 0.0651 g of an oxime-based photoinitiator (OXE-02, Ciba-Geigy Corporation), 0.0042 g of a leveling surfactant (silicone-based surfactant BYK 333, BYK Corporation), 0.0084 g of an adhesion assisting agent (KBE-9007, Shin-Etsu Chemical Co., Ltd.), and 8.9 g of a black organic pigment composition (lactam black:carbon black=50 parts by weight:0 parts by weight) obtained in Preparation Example 4 in 9.2094 g of propylene glycol-1-monomethyl ether-2-acetate.

Example 2

A photosensitive resin composition having black alkali developing properties was obtained by well stirring 1.0874 g of a photopolymerizable unsaturated resin obtained in Preparation Example 2, 0.7249 g of dipentaerythritol hexaacrylate, 0.0651 g of an oxime-based photoinitiator (OXE-02, Ciba-Geigy Corporation), 0.0042 g of a leveling surfactant (silicone-based surfactant BYK 333, BYK Corporation), 0.0084 g of an adhesion assisting agent (KBE-9007, Shin-Etsu Chemical Co., Ltd.), and 8.9 g of a black organic pigment composition (lactam black:carbon black=50 parts by weight:0 parts by weight) obtained in Preparation Example 4 in 9.2094 g of propylene glycol-1-monomethyl ether-2-acetate.

Example 3

A black alkali developing type photosensitive resin composition was obtained by well stirring 1.0723 g of a photopolymerizable unsaturated resin obtained in Preparation Example 3, 0.7184 g of dipentaerythritol hexaacrylate, 0.0651 g of an oxime-based photoinitiator (OXE-02, Ciba-Geigy Corporation), 0.0042 g of a leveling surfactant (silicone-based surfactant BYK 333, produced by BYK Corporation), 0.0084 g of an adhesion assisting agent (KBE-9007, Shin-Etsu Chemical Co., Ltd.), and 8.9 g of a black organic pigment composition (lactam black:carbon black=50 parts by weight:0 parts by weight) obtained in Preparation Example 4 in 9.2094 g of propylene glycol-1-monomethyl ether-2-acetate.

Example 4

An alkali developing type photosensitive resin composition was prepared in the same method as using the Example 1, except that a black organic pigment and inorganic pigment composition of the Preparation Example 5 (lactam black:carbon black=35 parts by weight:15 parts by weight) was used, instead of a black organic pigment composition of Preparation Example 4 in Example 1.

Example 5

An alkali developing type photosensitive resin composition was prepared using the same method as in Example 1, except that a black organic pigment and inorganic pigment composition of the Preparation Example 6 (lactam black:carbon black=30 parts by weight:20 parts by weight) was used, instead of a black organic pigment composition of Preparation Example 4 in Example 1.

Comparative Example 1

A photosensitive resin composition having black alkali developing properties was obtained by well stirring 1.7538 g of a bisphenol type binder (ZFR-2041H, Nippon Kayaku Co., Ltd.), 0.7249 g of dipentaerythritol hexaacrylate, 0.0651 g of an oxime-based photoinitiator (OXE-02, Ciba-Geigy Corporation), 0.0042 g of a leveling surfactant (silicone-based surfactant BYK 333, produced by BYK Corporation), 0.0084 g of an adhesion assisting agent (KBE-9007, Shin-Etsu Chemical Co., Ltd.), and 8.9 g of a black organic pigment and inorganic pigment composition obtained in Preparation Example 6 in 8.543 g of propylene glycol-1-monomethyl ether-2-acetate.

Comparative Example 2

A photosensitive resin composition having black alkali developing properties was obtained by well stirring 2.398 g of Cardo type binder (CBR-D07-3, Kyungin Synthetic Corporation), 0.7249 g of dipentaerythritol hexaacrylate, 0.0651 g of an oxime-based photoinitiator (OXE-02, Ciba-Geigy Corporation), 0.0042 g of a leveling surfactant (silicone-based surfactant BYK 333, BYK Corporation), 0.0084 g of an adhesion assisting agent (KBE-9007, Shin-Etsu Chemical Co., Ltd.), and 8.9 g of a black organic pigment and inorganic pigment composition obtained in Preparation Example 6 in 7.6188 g of propylene glycol-1-monomethyl ether-2-acetate.

Comparative Example 3

An alkali developing type photosensitive resin composition was prepared using the same method as in Example 1, except that a black organic pigment and inorganic pigment composition (lactam black:carbon black=25 parts by weight:25 parts by weight) of Preparation Example 7 was used, instead of a black organic pigment composition of Preparation Example 4 in Example 1.

Comparative Example 4

An alkali developing type photosensitive resin composition was prepared using the same method as in Example 1, except that a black organic pigment and inorganic pigment composition (lactam black:carbon black=15 parts by weight:35 parts by weight) of Preparation Example 8 was used, instead of a black organic pigment composition of Preparation Example 4 in Example 1.

Comparative Example 5

An alkali developing type photosensitive resin composition was prepared using the same method as in Example 1, except that a black inorganic pigment composition (lactam black:carbon black=0 parts by weight:50 parts by weight) of Preparation Example 9 was used, instead of a black organic pigment composition of Preparation Example 4 in Example 1.

[Formation of image patterns]

A film was formed by coating a photosensitive resin composition of the present invention on a pre-treated substrate to a desired thickness, e.g., a thickness of 2 to 25 μm by a conventional coating method such as a spin or slit coating method, a roll coating method, a screen printing method and an applicator method, and heating the coating at a temperature of 70 to 90°C for 1 to 10 minutes to remove the solvent.

An active ray of 200 to 500 nm was irradiated through a mask of a predetermined shape to form required patterns on the obtained film. Examples of light sources used for irradiation may include a low pressure mercury lamp, a high pressure mercury lamp, an ultra-high pressure mercury lamp, a metal halide lamp, and an argon gas laser, and may additionally include X-rays and electron rays, if necessary. Although the amount of light exposure varies depending on types and mixing amounts of respective components, and the thickness of a dried film, it is not more than 500 mJ/cm² (when measured by a 365 nm sensor) in the case of using the high pressure mercury lamp.

After performing the light exposing step, patterns were formed by dissolving and removing unnecessary parts using an aqueous alkali solution as a developer, thereby allowing only light-exposed parts to remain. The image patterns obtained by the development were cooled to room temperature, and post-baked at 230°C in a hot-air circulation type drying furnace for 20 minutes to produce image patterns.

[Resolution]

The resolution of the obtained image patterns was measured by observing minimum sizes of formed colored spacers using a micro-optical microscope.

[Measurements of optical density]

Absorbance is the amount of light when the luminous intensity of light becomes constant after the light of a certain wavelength passes through a certain layer, and optical density is obtained by dividing the absorbance value by thickness. In case where the luminous intensity of light becomes I after light having luminous intensity of I₀ at a specific wavelength band passes through a certain layer, the optical density is defined as log₁₀(I₀/I). Luminous intensity of light in a specific wavelength band was measured using an optical density meter (361T Tabletop Transmission Densitometer manufactured by X-Lite Corporation).

[Measurement of elastic recovery ratio]

After coating black photosensitive resin compositions prepared in the Examples and Comparative Examples on a glass substrate using a spin coater, the coated compositions were dried at 90°C for 2.5 minutes to form films. Pattern masks were placed on such obtained films, and 100 mJ/cm₂ of light having a wavelength of 365 nm was irradiated onto the films. Subsequently, after developing the films at 23°C for 1 minute using an aqueous solution diluted with 1% by weight of potassium hydroxide, the developed films were washed with pure water for 1 minute. Unnecessary parts were removed and only spacer patterns were remained. The formed spacer patterns were cured by heating to 230°C in an oven for 30 minutes to produce colored spacer patterns.

Using the black photosensitive resin compositions prepared in the Examples and Comparative Examples, colored spacers having a thicknesses (T) of 3.7 (±0.2) μm and a width (W) of 35 (±2) μm were prepared. The compression displacement and elastic recovery ratio of the colored spacers were measured according to the following methods using an elasticity measurement apparatus (DUH-W201S) manufactured by Shimadzu Corporation in Japan.

A flat-surfaced perpetrator with a diameter of 50 μm was used as a penetrator for pressing the patterns, and the measuring principle used a load-unload method. Loads given in the tests were 300 mN and 400 mN. The loading rate and holding time were constantly maintained at 0.45 gf/sec and 3 seconds, respectively. The elastic recovery ratio was obtained by measuring the thicknesses of the patterns after a loading and unloading with the flat-surfaced perpetrator for 3 seconds using a three-dimensional thickness measurement apparatus. The elastic recovery ratio means the ratio of a recovered distance (D₁-D₂) after a recovery time of 10 minutes to a distance (D₁) of the pattern that is indented when a loading is given to the pattern, and is represented by the following Equation 1:

[Equation 1]

Elastic recovery ratio (%) = [(D₁-D₂) x 100]/D₁

wherein D₁ (μm) is a compressed displacement; and D₂ (μm) a distance of the pattern that is indented after the recovery time.

[Measurement of dielectric constant]

Films having final thicknesses ranging from 1.5 to 2.5 μm were prepared by coating photoresists (PR) formed from the black photosensitive resin compositions prepared in the Examples and Comparative Examples on an indium tin oxide (ITO) glass and drying the coated photoresists (PR) on a hot plate under a temperature of 90°C for 2.5 minutes. A gold (Au) electrode with a diameter of 300 μm was deposited on the films to prepare samples. Capacitance values were measured using an HP 4294A Precision Impedance Analyzer, and dielectric constants were obtained using the measured capacitance values and the following Equation 2.

[Equation 2]

C = ε₀× ε × A/d

wherein C indicates an electric capacitance, ε₀ indicates a dielectric constant in a vacuum condition, ε indicates a relative dielectric constant of the film, A indicates an electrode area, and d indicates a photoresist (PR) thickness.

○: dielectric constant is 8 or less

×: dielectric constant is more than 8

[Evaluation Results]

Results of the tests were summarized in the following Table 1:

[Table 1]

As seen from Table 1, the subject photosensitive resin compositions of Examples 1 to 6 are uniformly excellent in optical density, dielectric constant, elastic recovery ratio, and resolution.

Particularly when comparing Examples 1 to 5 with Comparative Examples 1 to 5, it could be seen that Examples 1 to 5 were superior to Comparative Examples 1 and 2 in the resolution aspect, were superior to Comparative Examples 3, 4 and 5 in the dielectric constant aspect, and were superior to Comparative Examples 1 to 5 in the aspect of 300 mN and 400 mN elastic recovery ratios.

While the present invention has been shown and described in reference to the exemplary embodiments, it will be apparent to those skilled in the art that modifications and variations can be made without departing from the spirit and scope of the invention as defined by the appended claims. Therefore, the described embodiments above are exemplary and should not be interpreted limitedly.

Claims

A photopolymerizable unsaturated resin which is a product (P1) obtained by reacting an epoxy resin(A) represented by formula I with an unsaturated basic acid (B) to form an epoxy adduct (AB), and reacting said adduct with a polybasic acid anhydride (C).

[Formula I]

wherein the carbon labeled with * is replaced with a carbon labeled with * in one selected from the groupconsisting of

,
,
and
;

L¹ is C₁ _-10 alkylene, C₃ _-20 cycloalkylene or C₁ _-10 alkyleneoxy;

R¹, R², R³, R⁴, R⁵, R⁶ and R⁷ are the same or different and are each independently selected from the group consisting of hydrogen, C₁ _-10 alkyl, C₁ _-10 alkoxy, C₂ _-10 alkenyl and C₆ _-14 aryl;

R⁸ is selected from the group consisting of hydrogen, C₁ _-10 alkyl which is unsubstituted or substituted by halogen or hydroxy, C₂ _-10 alkenyl and C₆ _-14 aryl; and

n is an integer of from 0 to 10.
A photopolymerizable unsaturated resin which is a product (P2) obtained by reacting an epoxy resin (A) represented by formula I with an unsaturated basic acid (B) to form an epoxy adduct (AB), reacting said adduct with a polybasic acid anhydride (C) to form a product (P1), and further reacting said product (P1) with a monofunctional or polyfunctional epoxy compound (D).

[Formula I]

wherein the carbon labeled with * is replaced with a carbon labeled with * in one selected from the groupconsisting of
,
,
and
;

L¹ is C₁ _-10 alkylene, C₃ _-20 cycloalkylene or C₁ _-10 alkyleneoxy;

R¹, R², R³, R⁴, R⁵, R⁶ and R⁷ are the same or different and are each independently selected from the group consisting of hydrogen, C₁ _-10 alkyl, C₁ _-10 alkoxy, C₂ _-10 alkenyl and C₆ _-14 aryl;

R⁸ is selected from the group consisting of hydrogen, C₁ _-10 alkyl which is unsubstituted or substituted by halogen or hydroxy, C₂ _-10 alkenyl and C₆ _-14 aryl; and

n is an integer of from 0 to 10.
The photopolymerizable unsaturated resin according to claim 1, wherein said unsaturated basic acid (B) is at least one selected from the group consisting of acrylic acid, methacrylic acid, crotonic acid, cinnamic acid, sorbic acid, hydroxyethylmethacrylate·malate, hydroxyethylacrylate·malate, hydroxypropylmethacrylate·malate, hydroxypropylacrylate·malate and dicyclopentadiene·malate; and wherein said polybasic acid anhydride (C) is at least one selected from the group consisting of succinic anhydride, maleic anhydride, trimellitic anhydride, pyromellitic anhydride, 2,2'-3,3'-benzophenone tetra carboxylic dianhydride, 3,3'-4,4'-benzophenone tetra carboxylic dianhydride, ethylene glycol bis(anhydrotrimellitate), glycerol tris(anhydrotrimellitate), phthalic anhydride, hexahydrophthalic anhydride, methyl hydrophthalic anhydride, tetrahydrophthalic anhydride, nadic anhydride, methyl nadic anhydride, trialkyl tetrahydrophthalic anhydride, hexahydrophthalic anhydride, 5-(2,5-dioxotetrahydrofuryl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, an adduct of trialkyl tetrahydrophthalic anhydride and maleic anhydride, dodecenyl succinic anhydride and methyl himic anhydride.
The photopolymerizable unsaturated resin according to claim 2, wherein said monofunctional epoxy compound (D) is at least one selected from the group consisting of glycidyl methacrylate, methyl glycidyl ether, ethyl glycidyl ether, propyl glycidyl ether, isopropyl glycidyl ether, butyl glycidyl ether, isobutyl glycidyl ether, t-butyl glycidyl ether, pentyl glycidyl ether, hexyl glycidyl ether, heptyl glycidyl ether, octyl glycidyl ether, nonyl glycidyl ether, decyl glycidyl ether, undecyl glycidyl ether, dodecyl glycidyl ether, tridecyl glycidyl ether, tetradecyl glycidyl ether, pentadecyl glycidyl ether, hexadecyl glycidyl ether, 2-ethylhexyl glycidyl ether, allyl glycidyl ether, propargyl glycidyl ether, 2-methoxyethyl glycidyl ether, phenyl glycidyl ether, p-methoxyphenyl glycidyl ether, p-butylphenyl glycidyl ether, cresyl glycidyl ether, 2-methylcresyl glycidyl ether, 4-nonylphenyl glycidyl ether, benzyl glycidyl ether, p-cumylphenyl glycidyl ether, trityl glycidyl ether, 2, 3-epoxypropyl methacrylate, epoxylated soybean oil, epoxylated linseed oil, glycidyl butyrate, vinylcyclohexane monoxide, 1,2-epoxy-4-vinylcyclohexane, styrene oxide, pinene oxide, methylstyrene oxide, cyclohexene oxide and propylene oxide; and wherein said polyfunctional epoxy compound (D) is at least one selected from the group consisting of a polyglycidyl ether of a polyhydric alcohol or an adduct thereof with alkylene oxide; a polyglycidyl ether of a polybasic acid; a compound including cyclohexene oxide; and a compound including cyclopentene oxide.
The photopolymerizable unsaturated resin according to claim 1, wherein the epoxy adduct (AB) is obtained from the addition of the unsaturated basic acid (B) corresponding to from 0.1 to 5 equivalents of carboxyl groups to the epoxy resin (A) corresponding to 1 equivalent of epoxy groups; and wherein the photopolymerizable unsaturated resin is obtained form the reaction of the polybasic acid anhydride (C) corresponding to from 0.1 to 5 equivalents of acid anhydride groups with the epoxy adduct (AB) corresponding to 1 equivalent of hydroxyl groups.
The photopolymerizable unsaturated resin according to claim 2, wherein the monofunctional or polyfunctional epoxy compound (D) corresponding to from 0.1 to 5 equivalents of epoxy groups in the monofunctional or polyfunctional epoxy compound (D) reacts with the epoxy adduct (AB) corresponding to 1 equivalent of hydroxyl groups.
A photosensitive resin composition comprising the photopolymerizable unsaturated resin according to claim 1; a functional monomer having at least one ethylenically unsaturated bond; a polymerization initiator; a black organic pigment; and a solvent, and the black organic pigment is at least one selected from the group consisting of aniline black, lactam-based black and perylene black.
A photosensitive resin composition comprising the photopolymerizable unsaturated resin according to claim 2; a functional monomer having at least one ethylenically unsaturated bond; a polymerization initiator; a black organic pigment; and a solvent, and the black organic pigment is at least one selected from the group consisting of aniline black, lactam-based black and perylene black.
The photosensitive resin composition according to claim 7, wherein the photosensitive resin composition further comprises from 0.1 to 70 parts by weight of at least one black inorganic pigment selected from the group consisting of carbon black, chromium oxide, iron oxide and titanium black, based on 100 parts by weight of said black organic pigment.