JP2006220790A - Photosensitive resin composition for display panel, its hardened material, and spacer for display panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photosensitive resin composition capable of being used for forming a spacer which has high hardness, little plastic deformation amount when it is compressed, heat resistance required as a permanent film, and chemical durability; and the spacer formed by using the same. <P>SOLUTION: The photosensitive resin composition for the display panel contains (A) an alkali-soluble, carboxyl group-containing photosensitive resin, (B) a polymerizable compound having an ethylenic unsaturated bond, (C) a photopolymerization initiator, and (D) a compound having a oxazin ring. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a photosensitive resin composition for display panel, a cured product thereof, and a spacer for display panel made of the cured product. More specifically, the present invention relates to a photosensitive resin composition excellent in storage stability and compressive strength suitable as a material for forming a display panel spacer such as a liquid crystal panel and a touch panel, a cured product thereof, and a display panel spacer.

  In the liquid crystal panel, spacer particles such as glass beads and plastic beads having a predetermined particle diameter are used in order to keep the distance between the two substrates constant. However, since these spacer particles are randomly distributed on the glass substrate, if the spacer is present in the effective pixel portion, the spacer is reflected or the incident light is scattered and the contrast of the liquid crystal panel is lowered. There was a problem. In order to solve these problems, a method is used in which a spacer is formed by photolithography using a photosensitive resin composition.

  The spacer is required to withstand the compressive load when the liquid crystal panel is attached. However, a spacer formed using a conventional photosensitive resin composition composed of a photosensitive resin, a polyfunctional monomer and a photopolymerization initiator lacks sufficient hardness, and the color filter and the TFT array substrate There was a problem that the amount of plastic deformation under high temperature and high pressure during assembly (cell pressure bonding) was large, which hindered the function as a spacer, and there was still room for improvement.

  Further, since the spacer is used as a permanent film in the liquid crystal panel, heat resistance and chemical resistance are also required. Therefore, a thermosetting resin (see Patent Document 1) having both a carboxyl group and an epoxy group in the same molecule is used for the photosensitive resin composition used for this purpose in order to obtain characteristics as a permanent film. In some cases, a crosslinking agent such as an epoxy resin capable of reacting with the binder resin is added (see Patent Document 2). However, in the case of a photosensitive resin composition using an epoxy-based cross-linking agent, there is a problem that storage stability becomes a problem due to the high reactivity of the epoxy group that causes a cross-linking reaction, and there is a problem such as reduced workability. It was difficult to achieve both the properties of the object and the workability.

JP-A-11-133600 (Claims) JP 2001-324809 A (Claims)

  The present invention has been made based on the circumstances as described above, and its purpose is to have high hardness and small amount of plastic deformation at the time of compression, and to have both heat resistance and chemical resistance necessary as a permanent film. The object is to provide a photosensitive resin composition capable of forming a spacer. Another object of the present invention is to use the photosensitive resin composition for forming a spacer and to provide a spacer formed thereby.

In order to achieve the above object, basic aspects of the present invention include (A) an alkali-soluble carboxyl group-containing photosensitive resin, (B) a polymerizable compound having an ethylenically unsaturated bond, and (C) photopolymerization. There is provided a photosensitive resin composition comprising an initiator and (D) a compound having an oxazine ring.
In a more preferred embodiment, the compound (D) having an oxazine ring is a compound having an oxazine ring-containing group represented by the following general formula (1) and / or the following general formula (2). A photosensitive resin composition for a panel is provided.

In the formula, R ¹ represents an alkyl group having 1 to 12 carbon atoms, an optionally substituted cyclohexyl group, an aryl group which may have a substituent.

  Further, according to the present invention, a coating film forming step for applying and drying the photosensitive resin composition, and a photocuring treatment step for selectively irradiating the coating film obtained through the coating film forming step with active energy rays. , A cured product obtained through a photo-curing treatment step using an alkali developer to remove an unirradiated portion to obtain a pattern, and a step of heating and curing the pattern obtained in the alkali development step .

Furthermore, according to this invention, the spacer for display panels excellent in the compressive strength formed using the said photosensitive composition is provided.
In the present invention, “active energy rays” mean those including visible light, ultraviolet rays, far ultraviolet rays, electron beams, X-rays and the like.

  Since the photosensitive composition of the present invention is a curing system containing a compound having an oxazine ring as a thermosetting component (hereinafter referred to as an oxazine compound), the resulting cured product has sufficient hardness, heat resistance, and chemical resistance. ing. That is, the photosensitive composition of the present invention has various properties such as high hardness, high heat resistance, chemical resistance, and compressive strength while maintaining storage stability compared to the case of using an epoxy resin as a conventional crosslinking component. A cured product having excellent characteristics can be formed, and it is effective for applications such as spacers and planarization films.

The oxazine compound added as a thermosetting component to the photosensitive composition of the present invention is ring-opening polymerized by heat to give a strong cured product. Further, it is known that an acid such as a carboxylic acid is used as the ring-opening polymerization catalyst, and the reaction start temperature can be lowered by adding an acid catalyst. Although the oxazine compound alone requires a curing temperature of 200 ° C., in the photosensitive resin composition of the present invention, the carboxyl group in the alkali-soluble carboxyl group-containing photosensitive resin (A) acts catalytically, The ring-opening polymerization temperature of the oxazine ring can be lowered to about 160 ° C.
The composition used in the present invention includes not only a crosslinking reaction between an alkali-soluble carboxyl group-containing photosensitive resin (A) and a polymerizable compound (B) having an ethylenically unsaturated bond, but also a crosslinked structure of an oxazine compound. By forming an interpenetrating network chain structure, it is possible to form a strong cured product without impairing storage stability compared to conventional photosensitive resin compositions, which is required for spacers. It is possible to satisfy various properties such as high hardness and compressive strength.

  Hereinafter, each component of the photosensitive resin composition of this invention is demonstrated in detail. The alkali-soluble carboxyl group-containing photosensitive resin (A) is a carboxyl group-containing photosensitive resin that is soluble in an alkaline aqueous solution and has at least two ethylenically unsaturated bonds in one molecule, and is limited to a specific one. In particular, the resins listed below (either oligomers or polymers) can be suitably used.

(1) a carboxyl group-containing photosensitive resin obtained by adding an ethylenically unsaturated group as a pendant to a copolymer of (a) an unsaturated carboxylic acid and (b) a compound having an unsaturated double bond,
(2) (c) a secondary compound produced by reacting (a) an unsaturated carboxylic acid with a copolymer of a compound having an epoxy group and an unsaturated double bond and (b) a compound having an unsaturated double bond (D) a carboxyl group-containing photosensitive resin obtained by reacting a saturated or unsaturated polybasic acid anhydride with the hydroxyl group of
(3) (e) a copolymer of an acid anhydride having an unsaturated double bond and (b) a compound having an unsaturated double bond is reacted with a compound having a hydroxyl group and an unsaturated double bond. Carboxyl group-containing photosensitive resin obtained by
(4) (g) Esterification reaction (total esterification or partial esterification) of an epoxy group of a polyfunctional epoxy compound having at least two epoxy groups in one molecule and (h) a carboxyl group of an unsaturated monocarboxylic acid Preferably esterified), and (d) a carboxyl group-containing photosensitive resin obtained by further reacting the generated hydroxyl group with a saturated or unsaturated polybasic acid anhydride,
(5) (j) a carboxyl group-containing resin obtained by reacting a hydroxyl group-containing polymer with (d) a saturated or unsaturated polybasic acid anhydride; and (c) a compound having an epoxy group and an unsaturated double bond. Carboxyl group-containing photosensitive resin obtained by reaction,
(6) (g) a polyfunctional epoxy compound having at least two epoxy groups in one molecule, an unsaturated monocarboxylic acid (h), (k) at least two hydroxyl groups in one molecule, and an epoxy group Carboxyl group-containing photosensitivity obtained by reacting (d) a saturated or unsaturated polybasic acid anhydride with the reaction product (I) with a compound having one other reactive group other than the hydroxyl group that reacts with resin,
(7) Unsaturated group-containing polycarboxylic acid urethane comprising a reaction product of the reaction product (I), (d) a saturated or unsaturated polybasic acid anhydride, and (m) an unsaturated group-containing monoisocyanate. resin,
(8) (n) A polyfunctional oxetane compound having at least two oxetane rings in one molecule is reacted with (h) an unsaturated monocarboxylic acid, and the primary hydroxyl group in the resulting modified oxetane resin is (d ) A carboxyl group-containing photosensitive resin obtained by reacting a saturated or unsaturated polybasic acid anhydride.

The carboxyl group-containing photosensitive resin (1) has a sufficient photocuring depth in part of the carboxyl group of the copolymer of the unsaturated carboxylic acid (a) and the compound (b) having an unsaturated double bond. A compound having an ethylenically unsaturated group such as vinyl group, allyl group, acryloyl group, methacryloyl group and reactive group such as epoxy group, acid chloride, etc., such as glycidyl It is a resin obtained by reacting meth) acrylate and introducing an unsaturated double bond of the compound into a side chain. Since a part of the carboxyl group of the unsaturated carboxylic acid (a) which is one monomer component of the copolymer remains unreacted, the resulting carboxyl group-containing photosensitive resin is soluble in an aqueous alkali solution. It is. Therefore, a film formed from a composition containing such a resin can be stably developed with an alkaline aqueous solution after selective exposure.
In this specification, (meth) acrylate is a general term for acrylate and methacrylate, and the same applies to other similar expressions.

  The carboxyl group-containing photosensitive resin (2) includes (c) a compound having an epoxy group and an unsaturated double bond in the molecule, such as glycidyl (meth) acrylate, α-methylglycidyl (meth) acrylate, and the like. (B) The epoxy group of the copolymer of the compound having an unsaturated double bond is a proportion that improves the photocurability to such an extent that a sufficient photocuring depth can be obtained, and the carboxyl of the (a) unsaturated carboxylic acid. A group is reacted, an unsaturated double bond of the unsaturated carboxylic acid is introduced into the side chain, and the secondary hydroxyl group produced by the addition reaction is added to (d) a polybasic acid anhydride such as phthalic anhydride, It is a resin in which tetrahydrophthalic anhydride, hexahydrophthalic anhydride or the like is esterified to introduce a carboxyl group into the side chain.

  The carboxyl group-containing photosensitive resin (3) includes (e) an acid anhydride having an unsaturated double bond, such as maleic anhydride, itaconic anhydride, and the like (b) a compound having an unsaturated double bond. (F) a compound having a hydroxyl group and an unsaturated double bond, such as hydroxy, in such a proportion that the photocurability is improved to such a degree that a sufficient photocuring depth can be obtained. Alkyl (meth) acrylates, monomers obtained by reacting (meth) acrylate with caprolactone, hydroxyl groups such as macromonomers obtained by reacting (meth) acrylate with polycaprolactone oligomers are reacted to form a half ester, and the compound (f) It is a resin in which an unsaturated double bond is introduced into the side chain.

  The carboxyl group-containing photosensitive resin (4) is known as (g) bisphenol A type, bisphenol F type, bisphenol S type, phenol novolac type, cresol novolak type, biphenyl type, bixylenol type, N-glycidyl type, etc. (H) The carboxyl group of an unsaturated monocarboxylic acid such as (meth) acrylic acid is reacted with the epoxy group of a conventional epoxy compound at a ratio that improves the photocurability to such an extent that a sufficient photocuring depth is obtained. For example, it is a resin in which an epoxy acrylate is produced and the secondary hydroxyl group produced by the above addition reaction is esterified with the (d) polybasic acid anhydride to introduce a carboxyl group into the side chain. Such a carboxyl group-containing photosensitive resin is excellent in photocurability, and the backbone polymer epoxy acrylate exhibits hydrophobicity. Therefore, when the photocurable resin composition containing the resin is used, the hydrophobicity of the epoxy acrylate is advantageously used, and the development resistance of the deep part of the pattern which is difficult to be photocured is improved. As a result, the degree of freedom for setting conditions in the development and exposure processes is expanded.

  On the other hand, the carboxyl group-containing photosensitive resin of the above (5) is a ratio of improving the photocurability to such an extent that a sufficient photocuring depth can be obtained for the carboxyl group of the carboxyl group-containing resin. And an epoxy group of a compound having an unsaturated double bond, and the unsaturated double bond of the compound (c) is introduced into the side chain. Such a carboxyl group-containing photosensitive resin is excellent in photocurability and exhibits a sufficient photocuring depth.

  In the synthesis reaction of the carboxyl group-containing photosensitive resin (6), the polyfunctional epoxy compound (g) is reacted with an unsaturated monocarboxylic acid (h) (or compound (k)), and then the compound (k) (or There are a first method of reacting unsaturated monocarboxylic acid (h)) and a second method of reacting polyfunctional epoxy compound (g), unsaturated monocarboxylic acid (h) and compound (k) simultaneously. . Either method may be used, but the second method is preferable. Specific examples of the compound (k) having at least two or more hydroxyl groups and one other reactive group (for example, carboxyl group, secondary amino group, etc.) other than the hydroxyl group that reacts with the epoxy group in one molecule. Examples thereof include polyhydroxy-containing monocarboxylic acids such as dimethylolpropionic acid, dimethylolacetic acid, dimethylolbutyric acid, dimethylolvaleric acid, and dimethylolcaproic acid; dialkanolamines such as diethanolamine and diisopropanolamine.

  On the other hand, in the synthesis reaction of the unsaturated group-containing polycarboxylic acid urethane resin (7), the reaction product (I) is reacted with the polybasic acid anhydride (d), and then the unsaturated group-containing polyresin thus produced is reacted. It is preferable to react the unsaturated group-containing monoisocyanate (m) with the hydroxyl group in the carboxylic acid resin. Specific examples of the unsaturated monoisocyanate (m) include, for example, methacryloyl isocyanate, methacryloyloxyethyl isocyanate, organic diisocyanates (for example, tolylene diisocyanate, xylylene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, etc.) and the above one molecule. Examples thereof include reaction products obtained by reacting (meth) acrylates having one hydroxyl group in an equimolar ratio.

  The carboxyl group-containing photosensitive resin (8) is a polyfunctional oxetane using a compound having an oxetane ring as a starting material, instead of an epoxy resin that mainly generates a secondary hydroxyl group by reaction with an unsaturated monocarboxylic acid. By reacting the unsaturated monocarboxylic acid (h) with the compound (n), and further reacting the primary hydroxyl group of the resulting modified oxetane resin with the polybasic acid anhydride (d), the bonding site is heated. It is a resin that is not easily cut and has excellent thermal stability. By using this carboxyl group-containing photosensitive resin, it is an alkali development type photo-curable and thermosetting resin that has excellent heat resistance and thermal stability. A composition can be prepared.

  Among these alkali-soluble carboxyl group-containing photosensitive resins, it is more preferable to use the copolymer resins represented by the above (1), (2) and (3).

  The alkali-soluble carboxyl group-containing photosensitive resin (A) as described above may be used alone or in combination, but in any case, these are 5 to 80 parts by mass of the total amount of the composition, preferably It is preferable to mix | blend in the ratio of 10-60 mass parts. The carboxyl group-containing photosensitive resin has an acid value of 30 to 250 mgKOH / g, preferably 50 to 150 mgKOH / g, and a double bond equivalent of 350 to 2,000, preferably 400 to 1,500. A thing can be used suitably. When the acid value of the resin is lower than 30 mgKOH / g, the solubility in an alkaline aqueous solution is insufficient and development failure tends to occur. On the other hand, when it is higher than 250 mgKOH / g, it is not preferable because adhesion deterioration of the film and dissolution of the photocured part (exposed part) occur during development. Further, in the case of a carboxyl group-containing photosensitive resin, it is preferable that the double bond equivalent of the photosensitive resin is larger than 2,000 because the degree of freedom of work during development is narrow and a high exposure amount is required during photocuring. Absent.

  As the polymerizable compound (B) having an ethylenically unsaturated bond used in the present invention, a monofunctional, bifunctional, or trifunctional or higher (meth) acrylate has good polymerizability, and the strength of the obtained spacer, It is preferably used from the viewpoint of improving heat resistance.

  Examples of the monofunctional (meth) acrylate include 2-hydroxyethyl (meth) acrylate, carbitol (meth) acrylate, isobornyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, and 2- (meth) acryloyloxyethyl. And 2-hydroxypropyl phthalate. Examples of the commercially available products include Aronix M-101, M-111, M-114 (above, manufactured by Toagosei Co., Ltd.), KAYARAD TC-110S, TC-120S (above, Nippon Kayaku Co., Ltd.). Product), Biscoat 158, 2311 (manufactured by Osaka Organic Chemical Industry Co., Ltd.).

  Examples of the bifunctional (meth) acrylate include ethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, and polypropylene glycol di (meth) acrylate. , Tetraethylene glycol di (meth) acrylate, bisphenoxyethanol full orange acrylate, and the like. Examples of commercially available products include Aronix M-210, M-240, M-6200 (above, manufactured by Toagosei Co., Ltd.), KAYARAD HDDA, HX-220, R-604 (above, Nippon Kayaku). Manufactured by Co., Ltd.), Viscoat 260, 312 and 335HP (above, manufactured by Osaka Organic Chemical Industry Co., Ltd.).

  Examples of the trifunctional or higher functional (meth) acrylate include trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, tri ((meth) acryloyloxyethyl) phosphate, and pentaerythritol tetra (meth) acrylate. , Dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and the like. Examples of the commercially available products include Aronix M-309, M-400, M-402, M-405, M-450, M-7100, M-8030, M-8060, and M- 1310, same M-1600, same M-1960, same M-8100, same M-8530, same M-8560, same M-9050, same TO-1450 (above, manufactured by Toagosei Co., Ltd.), KAYARAD TMPTA, DPHA, DPCA-20, DPCA-30, DPCA-60, DPCA-120 (above, manufactured by Nippon Kayaku Co., Ltd.), Biscote 295, 300, 360, GPT, 3PA, 400 (manufactured by Osaka Organic Chemical Industry Co., Ltd.). These monofunctional, bifunctional, or trifunctional or higher (meth) acrylates are used alone or in combination.

  The suitable range of the usage-amount of the polymeric compound (B) which has the above ethylenically unsaturated bonds is 5-50 mass parts with respect to 100 mass parts of said alkali-soluble carboxyl group-containing photosensitive resin (A). The ratio is preferably 10 to 40 parts by mass.

  As the photopolymerization initiator (C), known compounds that generate radicals upon irradiation with active energy rays can be used, for example, acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy. 2-phenylacetophenone, p-dimethylaminopropiophenone, dichloroacetophenone, trichloroacetophenone, p-tert-butyltrichloroacetophenone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1- [4- (methylthio) phenyl]- Acetophenones such as 2-morpholino-propan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1, N, N-dimethylaminoacetophenone; benzophenone, methylbenzophenone Benzophenones such as 2-chlorobenzophenone, 4,4′-dichlorobenzophenone, 4,4′-bisdimethylaminobenzophenone, 4,4′-bisdiethylaminobenzophenone, Michler's ketone, 4-benzoyl-4′-methyldiphenyl sulfide; benzyl Benzoin ethers such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin isobutyl ether; ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal; thioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, Thioxanthones such as 2,4-diethylthioxanthone and 2,4-diisopropylthioxanthone; 2-methylanthraquinone, 2-ethyl Anthraquinones such as luanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, 2-aminoanthraquinone and 2,3-diphenylanthraquinone; organic peroxides such as benzoyl peroxide and cumene peroxide; 2,4,5 -Thiol compounds such as triarylimidazole dimer, riboflavin tetrabutyrate, 2-mercaptobenzoimidazole, 2-mercaptobenzoxazole, 2-mercaptobenzothiazole; 2,4,6-tris-s-triazine, 2,2 , 2-tribromoethanol, tribromomethylphenylsulfone, and the like; 2,4,6-trimethylbenzoyldiphenylphosphine oxide and the like. Other examples include acridine compounds and oxime esters. These compounds can be used alone or in combination of two or more.

  Further, the photopolymerization initiator (C) as described above includes N, N-dimethylaminobenzoic acid ethyl ester, N, N-dimethylaminobenzoic acid isoamyl ester, pentyl-4-dimethylaminobenzoate, triethylamine, triethanolamine. Of tertiary amines such as β-thiodiglycol, sensitizing dyes such as (keto) coumarin and thioxanthene, and alkyl borates such as cyanine, rhodamine, safranine, malachite green, and methylene blue Such photosensitizers or accelerators can be used alone or in combination of two or more.

  A preferable combination of the photopolymerization initiator (C) is 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one (for example, Irgacure 907 manufactured by Ciba Specialty Chemicals). ), 2-chlorothioxanthone (for example, Kayacure CTX manufactured by Nippon Kayaku Co., Ltd.), 2,4-diethylthioxanthone (for example, Kayacure DETX manufactured by Nippon Kayaku Co., Ltd.), 2-isopropylthioxanthone, 4-benzoyl-4 ′ -Combination with methyldiphenyl sulfide and the like.

  Moreover, the suitable range of the usage-amount of the above photoinitiators (C) is 0.01-30 mass parts with respect to 100 mass parts of said alkali-soluble carboxyl group-containing photosensitive resin (A), Preferably Is a ratio of 0.1 to 20 parts by mass. When the blending ratio of the radical photopolymerization initiator is less than 0.01 parts by mass, the photocurability is deteriorated. On the other hand, when it is more than 30 parts by mass, the properties of the cured coating film are deteriorated, and the storage stability is also increased. Is not preferable because of worsening.

  As the compound (D) having the oxazine ring, any oxazine compound having at least one oxazine ring-containing group represented by the following general formula (3) in the molecule can be used. It is not limited.

In the formula, R ¹ represents an alkyl group having 1 to 12 carbon atoms, a cyclohexyl group which may have a substituent, or an aryl group which may have a substituent. R ² represents an organic group shown below. n represents an integer of 2 to 4.

  A more specific example of the oxazine compound is a compound having an oxazine ring obtained by reacting a phenol compound, formalin, and a primary amine, and 2,2′- derived from bisphenol A, formalin and aniline. Isopropylidenebis (3,4-dihydro-3-phenyl-2H-1,3-benzoxazine and methylidenebis (3,4-dihydro-3-phenyl-2H-1, derived from bisphenol F and formalin and aniline) Examples thereof include 3-benzoxazine, an oxazine compound derived from phenol novolac resin, formalin and aniline.

  In addition, a compound having an oxazine ring represented by the following general formula (4), which is a reaction product of a compound having two or more primary aromatic amino groups, a phenol compound, and formalin can be used. It is not limited to compounds.

In the formula, R ³ represents an organic group shown below. n represents an integer of 2 to 4.

  Among these oxazine compounds, the oxazine compound represented by the general formula (4) is preferably used because it has a high effect of improving hardness.

  5-50 mass parts is preferable with respect to 100 weight part of alkali-soluble photosensitive resin (A), and, as for the compounding quantity of the oxazine compound in the photosensitive resin composition of this invention, 10-40 weight part is more preferable. When the blending amount of the oxazine compound is less than 5 parts by mass, a significant improvement in physical properties is not achieved because the ratio of the oxazine compound in the composition is small. On the other hand, when the amount exceeds 50 parts by mass, the alkali developability is lowered and the resolution is deteriorated.

  In the photosensitive resin composition of the present invention, an organic solvent can be used as needed to uniformly dissolve the photosensitive resin composition or adjust the viscosity. The organic solvent preferably dissolves each component uniformly and does not react with each component. If the solubility of each component in the organic solvent is low, it is difficult to uniformly dissolve, and it is difficult to ensure the transparency required for the spacer, which is not preferable.

  Specific examples of these organic solvents include, for example, alcohols such as methanol and ethanol; ethers such as tetrahydrofuran; glycol ethers such as ethylene glycol monomethyl ether and ethylene glycol monoethyl ether; ethylene glycol such as methyl cellosolve acetate and ethyl cellosolve acetate. Alkyl ether acetates; diethylene glycols such as diethylene glycol monomethyl ether, diethylene glycol monoethyl ether and diethylene glycol dimethyl ether; propylene glycol monoalkyl ethers such as propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol propyl ether and propylene glycol butyl ether; Propylene glycol alkyl ether acetates such as pyrene glycol methyl ether acetate, propylene glycol ethyl ether acetate, propylene glycol propyl ether acetate, propylene glycol butyl ether acetate; propylene glycol methyl ether propionate, propylene glycol ethyl ether propionate, propylene glycol propyl Propylene glycol alkyl ether acetates such as ether propionate and propylene glycol butyl ether propionate; aromatic hydrocarbons such as toluene and xylene; ketones such as methyl ethyl ketone and 4-hydroxy-4-methyl-2-pentanone; and Methyl acetate, ethyl acetate, propyl acetate, butyrate , Ethyl 2-hydroxypropionate, methyl 2-hydroxy-2-methylpropionate, ethyl 2-hydroxy-2-methylpropionate, methyl hydroxyacetate, ethyl hydroxyacetate, butyl hydroxyacetate, methyl lactate, ethyl lactate, propyl lactate Butyl lactate, methyl 3-hydroxypropionate, ethyl 3-hydroxypropionate, propyl 3-hydroxypropionate, methyl 3-hydroxypropionate, ethyl 3-butoxypropionate, propyl 3-butoxypropionate, 3-butoxypropion And esters such as butyl acid.

  Among these organic solvents, glycol ethers, glycol alkyl ether acetates, esters and diethylene glycols are preferably used because of their solubility, reactivity with each component, and ease of film formation. Alternatively, two or more types can be mixed and used.

  Moreover, the photosensitive resin composition of this invention may contain other components other than the above as needed in the range which does not impair the objective of this invention.

  Here, as another component, the crosslinking agent which can react with the carboxyl group in alkali-soluble carboxyl group containing photosensitive resin is mentioned. Specific examples include epoxy compounds and oxetane compounds. Epoxy compounds include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, alkylphenol novolac type epoxy resin, biphenol type epoxy resin, and bixylenol type epoxy. Resin, naphthalene type epoxy resin, dicyclopentadiene type epoxy resin, epoxidized product of condensation product of phenol and aromatic aldehyde having phenolic hydroxyl group, or bromine atom-containing epoxy resin or phosphorus atom-containing epoxy resin, triglycidyl Known and commonly used materials such as isocyanurates and alicyclic epoxy resins can be used alone or in combination of two or more.

Examples of oxetane compounds include bisphenol A type oxetane compounds, bisphenol oxetane compounds, bisphenol S type oxetane compounds, xylylene type oxetane compounds, phenol novolac type oxetane compounds, cresol novolac type oxetane compounds, alkylphenol novolak type oxetane compounds, biphenol type oxetane compounds, Xylenol-type oxetane compounds, naphthalene-type oxetane compounds, dicyclopentadiene-type oxetane compounds, oxetaneates of condensates of phenols and aromatic aldehydes having a phenolic hydroxyl group, etc., alone or in combination of two or more known ones Can be used.
However, an oxetane compound is preferable because an epoxy compound is deteriorated in storage stability when added.

When adding the above epoxy compound or oxetane compound, it is also possible to add a known and usual reaction accelerator as long as the storage stability is not impaired.
Examples of the reaction accelerator include tertiary amines, imidazoles, quaternary onium salts, tertiary phosphines, phosphonium ylides, acetylacetone metal complexes, or crown ether complexes. These may be used alone or in combination of two or more. May be used in combination.

  In addition, in order to improve coatability, known and commonly used surfactants such as fluorine-based, silicone-based and polymer-based, antifoaming agents, leveling agents, and silane coupling agents to improve adhesion to the substrate Adhesive aids such as can be used.

The photosensitive resin composition of the present invention as described above becomes a cured product pattern through the steps described below. That is, a coating film forming step of applying and drying the photosensitive resin composition of the present invention, a photocuring treatment step of selectively irradiating active energy rays to the coating film obtained through the coating film forming step, and a photocuring treatment. After the step, a cured product pattern is formed through an alkali development step of removing a non-irradiated portion using an alkali developer to obtain a pattern, and a curing step of heating and curing the pattern obtained in the alkali development step.
(1) Coating film forming step In this step, the photosensitive resin composition of the present invention is a solid colored photosensitive resin composition layer (hereinafter referred to as a substrate or the like) formed on a substrate or a substrate in advance. And volatile components such as a solvent are removed from the applied photosensitive resin composition layer and dried.

  Here, examples of the substrate include flat substrates such as a glass substrate, a silicon substrate, a polycarbonate substrate, a polyester substrate, an aromatic polyamide substrate, a polyamideimide substrate, a polyimide substrate, an Al substrate, and a GaAs substrate. These substrates may be subjected to pretreatment such as chemical treatment with chemicals such as a silane coupling agent, plasma treatment, ion plating treatment, sputtering treatment, gas phase reaction treatment, and vacuum deposition treatment. When a silicon substrate or the like is used as the substrate, a charge coupled device (CCD), a thin film transistor (TFT), or the like may be formed on the surface of the silicon substrate.

  In order to apply the photosensitive resin composition on the substrate, for example, the photosensitive resin composition of the present invention can be applied by spin coating (spin coating), casting coating, roll coating, slit & spin coating. The coating may be performed on a substrate or the like by a known coating method such as coating using a liquid-saving coater such as a spinless coater, and then a volatile component such as a solvent may be volatilized by heating. In this way, a layer made of the solid content of the photosensitive resin composition is formed on the substrate or the like.

(2) Photo-curing treatment (exposure) step In this step, an active energy ray is selectively applied to the coating film obtained in the step (1) (hereinafter also referred to as a photosensitive resin composition layer). Irradiate.
Here, for exposure, for example, active energy rays may be selectively irradiated through a photomask. As the exposure light source, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a xenon lamp, a metal halide lamp, or the like is usually suitable. A laser beam or the like can also be used as the exposure active beam. In addition, electron beams, α rays, β rays, γ rays, X rays, neutron rays and the like can be used.
The light beam is irradiated through a photomask, and this photomask is provided, for example, with a light shielding layer that shields the light beam on the surface of a glass plate. The portion of the glass plate that is not provided with the light-shielding layer is a light-transmitting portion that transmits light. The photosensitive resin composition layer is exposed in a pattern according to the pattern of the light-transmitting portion, and the light is irradiated. An unirradiated region that has not been irradiated and an irradiated region that has been irradiated with the light beam are generated. The irradiation amount of light in the irradiation region is the weight average molecular weight of the binder polymer, the monomer ratio, the content, the type and content of the photopolymerizable compound, the type and content of the photopolymerization initiator, and the photopolymerization initiation aid. It is appropriately selected depending on the type and content.

(3) Alkali development step The coating film on the substrate after the step (2) is developed.
Here, for the development, for example, the exposed photosensitive resin composition layer may be brought into contact with the developer, and specifically, the substrate having the photosensitive resin composition layer formed on the surface thereof. May be immersed in the developer or the developer may be sprayed in a shower. Examples of the developer include aqueous solutions of alkaline compounds such as sodium carbonate, potassium carbonate, sodium hydroxide, potassium hydroxide, tetramethylammonium hydroxide, and organic amines. By the development, an unirradiated area of the photosensitive resin composition layer that has not been irradiated with the light beam is removed. On the other hand, the light irradiation area remains as it is to form a pattern. After development, the desired pattern can be obtained usually by washing with water and drying.

(4) Curing Step The coating pattern on the substrate that has finished the step (3) is cured by heating, and the mechanical strength can be further improved.
Here, the heating temperature is usually 180 ° C. or higher, preferably 200 ° C. or higher, and usually 250 ° C. or lower. When the heating temperature is 180 to 250 ° C., the mechanical strength of the coating film is improved and the solvent resistance and liquid crystal resistance are improved, which is preferable. The heating time is usually 5 minutes to 120 minutes, preferably 10 minutes to 90 minutes, and more preferably 15 minutes to 60 minutes. When the heating time is 5 minutes to 120 minutes, the mechanical strength of the coating film is improved, which is preferable.

  As described above, a cured product pattern using the photosensitive resin composition of the present invention is formed, which is suitably used as a display spacer.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In the following description, “part” means part by mass unless otherwise specified.

Preparation of alkali-soluble photosensitive resin solution:
(Synthesis example)
In a separable flask equipped with a stirrer, a reflux condenser, and a thermometer, 4.1 parts of azobisisobutyronitrile and 125 g of propylene glycol monomethyl ether acetate are charged and heated in a hot water bath to an internal temperature of 70 ° C. A mixture of 55 parts of methyl methacrylate, 20.8 parts of styrene and 42.7 parts of glycidyl methacrylate was added dropwise over 3 hours to carry out a polymerization reaction. Furthermore, it stirred at 70 degreeC for 3 hours, and it confirmed that the unreacted monomer did not exist by GPC. To this polymer, 23.4 parts of acrylic acid and 0.8 part of triphenylphosphine were added and reacted at 80 to 90 ° C. for 16 hours. After confirming the disappearance of the epoxy group by IR spectrum, 45.7 parts of tetrahydrophthalic anhydride was added, and the mixture was further reacted at 80 ° C. for 8 hours to obtain Resin-A. In addition, the acid value of Resin-A was 90 mgKOH / g, and the molecular weight (Mw) in GPC was 15000. The solid content concentration of this resin varnish was 60% by weight.

Examples 1 to 4 and Comparative Example Preparation of Photosensitive Resin Composition Using the raw materials shown in Table 1, each component was blended at the blending ratio shown in Table 2, and stirred for 3 hours at room temperature to dissolve each component. The mixture was filtered through a 0.45 μm Millipore filter to obtain a photosensitive composition.

(1) Evaluation of resolution Using a spinner on a glass substrate, the composition solution was applied for 20 seconds at a rotation speed of 1000 rpm, and then pre-baked on a hot plate at 90 ° C. for 3 minutes to form a dried coating film. Formed. The coating film obtained above was irradiated with 100 mJ / cm ^{2 of} ultraviolet light having an intensity of 12 mW / cm ² at 365 nm through a mask having a dot pattern of φ10 μm. The ultraviolet irradiation at this time was performed in an oxygen atmosphere (in air), and the exposure gap was 100 μm. Next, after developing for 120 seconds at 25 ° C. using a 0.4 wt% aqueous solution of tetramethylammonium hydroxide, it was washed with pure water for 30 seconds. The spacer pattern formed above was cured by heating at 230 ° C. for 60 minutes in an oven.
The case where a pattern having a dot diameter of 10 μm can be resolved with the spacer pattern obtained above is marked with ◯, and the case where the pattern is not resolved is marked with ×. The results are shown in Table 3.

(2) Evaluation of NMP resistance Using a spinner on a glass substrate, the above composition solution was applied for 20 seconds at a rotation speed of 1000 rpm, and then pre-baked on a hot plate at 90 ° C. for 3 minutes to form a dried coating film. Formed. The entire surface of the coating film obtained above was irradiated with 100 mJ / cm ^{2 of} ultraviolet light having an intensity at 365 nm of 12 mW / cm ² with an integrated light amount. The ultraviolet irradiation at this time was performed in an oxygen atmosphere (in air), and the exposure gap was 100 μm. Thereafter, it was cured by heating in an oven at 230 ° C. for 60 minutes.
The cured coating film obtained above was rubbed with a waste impregnated with N-methyl-2-pyrrolidone (NMP) to observe the surface state. The case where there was no change at all was marked as ◯, and the case where the surface was dissolved or softened and scratched, was marked as x.

(3) γ-Butyrolactone Resistance The cured coating film obtained in the same manner as in (2) above was rubbed with a waste impregnated with γ-butyrolactone to observe the surface condition. The case where there was no change at all was marked as ◯, and the case where the surface was dissolved or softened and scratched, was marked as x.

(4) Pencil hardness The cured coating film obtained in the same manner as in (2) above was performed according to the test method of JIS K5600-5-4, and the hardness of the hardest pencil that did not cause scars on the coating film surface was obtained. .

(5) Compressive strength A pattern having a film thickness of 5 μm and a dot diameter of 30 μm was formed, and a spacer pattern thermally cured at 230 ° C. for 60 minutes was evaluated using a micro hardness meter. The amount of deformation when a load of 50 mN was applied was measured with a flat indenter having a diameter of 50 μm. The case where this numerical value was 0.6 or less was marked with ◯, and the case where it was larger than 0.6 was marked with ×.

(6) Storage stability The above photosensitive composition was stored in an oven at 40 ° C. for 14 days, when gelation or a marked increase in viscosity was observed. It was.

Table 3 summarizes the test results of the above items.

As is apparent from the results shown in Table 3, in Examples 1 to 4 which are the photosensitive compositions of the present invention, the cured product is excellent in high hardness, compressive strength and chemical resistance, and also in storage stability. It became clear that it was excellent.

Claims (6)

(A) An alkali-soluble carboxyl group-containing photosensitive resin, (B) a polymerizable compound having an ethylenically unsaturated bond, (C) a photopolymerization initiator, and (D) a compound having an oxazine ring. A photosensitive resin composition for a display panel. 2. The photosensitive resin composition according to claim 1, wherein the compound (D) having an oxazine ring is a compound having an oxazine ring-containing group represented by the following general formula (1) and / or the following general formula (2).



In the formula, R ¹ represents an alkyl group having 1 to 12 carbon atoms, an optionally substituted cyclohexyl group, an aryl group which may have a substituent.



The compounding quantity of the compound (D) which has the said oxazine ring is 5-50 mass parts with respect to 100 mass parts of the said carboxyl group-containing photosensitive resin (A), It is characterized by the above-mentioned. Photosensitive resin composition. The photosensitive resin composition according to any one of claims 1 to 3, further comprising an oxetane compound. The coating film formation process which apply | coats and drys the photosensitive resin composition as described in any one of Claims 1 thru | or 4, and the active energy ray is selectively irradiated to the coating film obtained through this coating film formation process A cured product obtained through a photocuring treatment step, an alkali developing step for removing a non-irradiated portion using an alkali developer after the photocuring treatment step, and a step for heating and curing the pattern obtained in the alkali developing step. . The spacer for display panels obtained using the composition as described in any one of Claims 1 thru | or 4.