JP2010107863A - Photosensitive resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photosensitive resin composition for a photospacer, which has good alkali developability and the cured product of which has excellent flexibility and elastic recovery property. <P>SOLUTION: The alkali developable photosensitive resin composition (Q) includes a hydrophilic resin (A) having a carboxyl group, a polyfunctional acrylate monomer (B), a liquid polybutadiene copolymer (C), and a photoradical polymerization initiator (D), wherein the liquid polybutadiene copolymer (C) includes an acrylonitrile component (a) in an amount of 10-50 wt.% based on the solid weight of the liquid polybutadiene copolymer (C). A cured film formed on a glass substrate by photocuring the photosensitive resin composition (Q) has a transmittance for light of 400 nm of ≥90%. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a photosensitive resin composition which is cured by a process including light irradiation and can be developed with an alkali, and a photospacer provided for maintaining a gap in a liquid crystal cell formed using the composition. .

  In recent years, liquid crystal display devices have attracted attention, and photosensitive resins are frequently used in the manufacturing process. For example, the portion corresponding to the pixel on the color filter is a color pigment dispersion resist, and the resist is also used for the black matrix. As a resist used for such a portion, a so-called negative resist is often used in which only a portion irradiated with light is hardened when exposed through a photomask and an unexposed portion is peeled off by development.

Now, in the liquid crystal display device technology, in order to maintain the thickness of the liquid crystal layer between both the color filter side substrate and the thin film transistor (TFT) side substrate, glass or resin transparent spherical particles (beads) called spacers are used. Sprayed inside the cell.
However, since these spacers are transparent particles, if there is a liquid crystal and a spacer in the pixel, light leaks through the spacer particles during black display, and the liquid crystal is enclosed. The presence of spacer particles between the two substrates disturbs the orientation of the liquid crystal molecules in the vicinity of the spacer particles, causing light leakage at this portion, resulting in a problem that the contrast of the liquid crystal display device is lowered and the display quality is adversely affected. is doing.
Also, for example, in a liquid crystal display device in which the distance between the two substrates (the thickness of the liquid crystal layer) is narrow, such as a ferroelectric liquid crystal, the distance between the two substrates can be maintained uniformly and accurately using this spacer particle. It is difficult.

As a technique for solving such a problem, for example, a photosensitive resin is used and a photolithography method such as partial pattern exposure and development is performed on a black matrix in a lattice pattern located at a desired position, for example, between pixels. A method of forming a columnar resin spacer has been proposed (Patent Document 1).
Such a spacer is hereinafter referred to as a photo spacer. Since the photo spacer can be formed at a position avoiding the pixels, it does not adversely affect the display quality as described above, and the display quality can be improved.

On the other hand, in recent years, as mother glass for LCD (Liquid Crystal Display) manufacture becomes larger, a drop method (ODF method) (ODF: One Drop Fill) has been proposed instead of the conventional liquid crystal inflow method (vacuum suction method). Yes. In the ODF method, after a predetermined amount of liquid crystal is dropped, the liquid crystal is injected by being sandwiched between substrates, so that the number of processes and the process time can be reduced as compared with the conventional vacuum suction method.
However, in the ODF method, a predetermined amount of liquid crystal calculated from the cell gap is dropped and held, so that flexibility in correcting height variations and subtle pressure in the plane applied at that time are obtained. It is desirable for photo spacers to have elastic properties that do not affect the difference. That is, a photo spacer having excellent flexibility and a high elastic recovery rate is required.
Photo spacers that do not have the above-mentioned characteristic flexibility and elastic properties may cause bubbles in the liquid crystal when the panel is manufactured. The cell gap is not uniform, and the display quality of the liquid crystal display device deteriorates. Inconveniences such as non-uniformity occur.

As a proposal for solving the problem that the display quality is deteriorated without the cell gap being uniform, for example, a photosensitive resin composition for a photospacer having alkali developability (Patent Document 2) has been proposed. In this proposal, a photo spacer having excellent mechanical strength is proposed by using a photopolymerizable monomer, a photopolymerization initiator, and an epoxy resin having alkali developability and reactivity in combination.
However, in a composition in which such an epoxy resin and a carboxylic acid component necessary for alkali development coexist, a crosslinking reaction proceeds between the epoxy group and the carboxylic acid. As a result, there is a problem that the completed photo spacer becomes brittle and the elastic recovery characteristic deteriorates.

In recent years, a new proposal (Patent Document 3) has been proposed as a material for forming a photo spacer having a characteristic that solves the shortage of the elastic recovery characteristic as described above. In this proposal, the amount of polyfunctional monomer in the total solid content is improved by 50 to 70%.
However, when a large amount of polyfunctional monomer is used, there is a problem that alkali developability and adhesion to a substrate are deteriorated.
JP H11-174673 A JP 2001-226449 A JP 2002-174812 A

  The present invention provides a photosensitive resin composition for a photospacer having good alkali developability and having a cured product with excellent flexibility and excellent elastic recovery characteristics, and further, excellent flexibility and excellent It is an object to provide a photospacer having elastic recovery characteristics and excellent adhesion.

The inventors of the present invention have arrived at the present invention as a result of intensive studies to solve the above problems.
That is, the present invention is a photosensitive resin composition containing a hydrophilic resin (A) having a carboxyl group, a polyfunctional acrylate monomer (B), a liquid polybutadiene copolymer (C) and a photo radical polymerization initiator (D). The liquid polybutadiene copolymer (C) contains the acrylonitrile component (a) in an amount of 10 to 50% by weight based on the solid content of the liquid polybutadiene copolymer (C) (Q). A 400 nm light transmittance of a cured film on a glass substrate formed by photo-curing the photosensitive resin composition (Q) is 90% or more, and the alkali-developable photosensitive resin Composition (Q); and a photospacer provided for maintaining a gap in a liquid crystal cell formed by curing the composition.

The photosensitive resin composition of the present invention and the photospacer obtained therefrom have the following effects.
(1) The photosensitive resin composition is excellent in alkali developability.
(2) The photo spacer is excellent in flexibility and elastic recovery characteristics.
(3) The photo spacer has excellent adhesion to the substrate.

The photosensitive resin composition of the present invention comprises a hydrophilic resin having a carboxyl group (A) [hereinafter sometimes simply referred to as (A)], a polyfunctional acrylate monomer (B) [hereinafter simply represented by (B )], Liquid polybutadiene copolymer (C) [hereinafter sometimes simply referred to as (C)], and radical photopolymerization initiator (D) [hereinafter simply referred to as (D). Is provided as an essential component, and provides a photo-spacer excellent in alkali developability, flexibility, elastic recovery characteristics and adhesion.
In addition, in the above and the following, for example, the expression with “(meth)” such as “(meth) acrylate” means “acrylate and / or methacrylate”.

  Below, (A)-(D) which is an essential structural component of the photosensitive resin composition of this invention is demonstrated in order.

The hydrophilicity index in the hydrophilic resin (A) having a carboxyl group in the present invention is defined by HLB. In general, the larger this value, the higher the hydrophilicity.
The preferred range of the HLB value of the hydrophilic resin (A) of the present invention varies depending on the resin skeleton of (A) (for example, vinyl resin, epoxy resin, polyester resin, etc.), but usually 4 to 19, preferably Is from 5 to 18, more preferably from 6 to 17.
When it is 4 or more, the developing property is further improved when developing the photosensitive resin, and when it is 19 or less, the water resistance of the cured product is further improved.
In addition, HLB in this invention is an HLB value by the Oda method, is a hydrophilicity-hydrophobicity balance value, and can be calculated from the ratio of the organic value and inorganic value of an organic compound.
HLB≈10 × Inorganic / Organic In addition, the values of inorganicity and organicity are given in the document “Surfactant Synthesis and Its Applications” (published by Tsuji Shoten, Oda, Teramura), page 501;・ Introduction to Surfactant ”(written by Takehiko Fujimoto, published by Sanyo Chemical Industries, Ltd.), page 198.

  Moreover, the solubility parameter (hereinafter referred to as SP value) of (A) is preferably 7 to 14, more preferably 8 to 13, and particularly preferably 11 to 13. When it is 7 or more, the developability can be further improved, and when it is 14 or less, the water resistance of the cured product is further improved.

  The SP value in the present invention is calculated by the method described in the following document proposed by Fedors et al.

“POLYMER ENGINEERING AND SCIENCE, FEBRUARY, 1974, Vol. 14, No. 2, Robert F. Fedors. (Pp. 147 to 154)” Those with close SP values are likely to mix with each other (highly dispersible), and this numerical value It is an index showing that things that are separated are difficult to mix.

The hydrophilic resin (A) of the present invention has one or more carboxyl groups in the molecule from the viewpoint of developability. The position of the carboxyl group may be the main chain end or the side chain of the hydrophilic resin (A).
The carboxyl group content is indicated by an acid value. When the acid value of (A) is 10 mgKOH / g or more, developability is more likely to be exhibited, and when it is 500 mgKOH / g or less, the water resistance of the cured product can be further improved.

The acid value in the present invention can be measured by an indicator titration method using an alkaline titration solution.
The method is as follows.
(I) About 1 g of a sample is precisely weighed and placed in an Erlenmeyer flask, and then a neutral methanol / acetone solution (a mixture of acetone and methanol at 1: 1 (volume ratio)) is added and dissolved.
(Ii) Add several drops of phenolphthalein indicator and titrate with 0.1 mol / L potassium hydroxide titration solution. The end point of neutralization is defined as the time when the indicator is slightly red for 30 seconds.
(Iii) Determine using the following equation.
Acid value (KOHmg / g) = (A × f × 5.61) / S
However, A: The number of mL of 0.1 mol / L potassium hydroxide titration solution.
f: Potency of 0.1 mol / L potassium hydroxide titration solution
S: Sampling amount (g)

Examples of the hydrophilic resin (A) of the present invention include a hydrophilic vinyl polymer (A1), a hydrophilic epoxy polymer (A2), a hydrophilic polyester polymer, a hydrophilic polyamide polymer, a hydrophilic polycarbonate polymer, and a hydrophilic polyurethane. System polymers and the like. (A) may be used by 1 type and may use 2 or more types together.
Among these, (A1) and (A2) are preferable from the viewpoint of photocurability of the photosensitive resin composition and the viewpoint of ease of production.

  Examples of the hydrophilic vinyl polymer (A1) include those having a hydrophilic group in the side chain and / or terminal of the vinyl polymer molecule. Examples of the hydrophilic group include a carboxyl group, a hydroxyl group, a sulfonic acid group, an amino group, an amide group, a polyether group, and a combination of two or more of these. In order to exhibit sufficient developability, those having a hydrophilic group in the side chain, particularly those having a carboxyl group are preferred.

  A preferred production method of (A1) is a method of vinyl polymerizing a hydrophilic group-containing vinyl monomer (a) and, if necessary, a hydrophobic group-containing vinyl monomer (b).

Examples of the hydrophilic group-containing vinyl monomer (a) include the following vinyl monomers (a1) to (a7).
(A1) Hydroxyl-containing vinyl monomer:
Hydroxyalkyl (meth) acrylate [2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, etc.], polyalkylene glycol mono (meth) acrylate [polyethylene glycol mono (meta ) Acrylate etc.], alkylol (meth) acrylamide [N-methylol (meth) acrylamide etc.], hydroxystyrene, 2-hydroxyethylpropenyl ether and the like. Among (a1), preferred is hydroxyalkyl (meth) acrylate, particularly 2-hydroxyethyl (meth) acrylate, from the viewpoint of alkali developability.

(A2) Carboxyl group-containing vinyl monomer:
Unsaturated monocarboxylic acids [such as (meth) acrylic acid, crotonic acid and cinnamic acid], unsaturated polyvalent (2-4 valent) carboxylic acids [such as (anhydrous) maleic acid, itaconic acid, fumaric acid and citraconic acid], Unsaturated polyvalent carboxylic acid alkyl (alkyl group having 1 to 10 carbon atoms) ester [maleic acid monoalkyl ester, fumaric acid monoalkyl ester, citraconic acid monoalkyl ester, etc.] and salts thereof [alkali metal salt (sodium salt) And potassium salts, etc.), alkaline earth metal salts (calcium salts and magnesium salts, etc.), amine salts and ammonium salts, etc.].
Of (a2), preferred is an unsaturated monocarboxylic acid from the viewpoint of hydrophilicity, and more preferred is (meth) acrylic acid.
(A3) Sulphonic acid group-containing vinyl monomer:
Examples thereof include vinyl sulfonic acid, (meth) allyl sulfonic acid, styrene sulfonic acid, α-methyl styrene sulfonic acid, 2- (meth) acryloylamido-2-methylpropane sulfonic acid, and salts thereof. Examples of the salt include alkali metal (sodium and potassium) salts, alkaline earth metal (calcium and magnesium) salts, primary to tertiary amine salts, ammonium salts and quaternary ammonium salts.

(A4) Amino group-containing vinyl monomer:
Tertiary amino group-containing (meth) acrylates [dialkylaminoalkyl (meth) acrylates such as dimethylaminoethyl (meth) acrylate and diethylaminoethyl (meth) acrylate)] and the like.
(A5) Amide group-containing vinyl monomer:
(Meth) acrylamide, N-alkyl (C1-6) (meth) acrylamide, diacetone acrylamide, N, N′-methylene-bis (meth) acrylamide, N, N-dialkyl (C1-6) or Diaralkyl (7 to 15 carbon atoms) (meth) acrylamide (for example, N, N-dimethylacrylamide and N, N-dibenzylacrylamide), methacrylformamide, N-methyl-N-vinylacetamide, cinnamic amide and cyclic amide (N-vinylpyrrolidone, N-allylpyrrolidone, etc.).
(A6) a quaternary ammonium base-containing vinyl monomer;
A quaternized product of a tertiary amino group-containing vinyl monomer having 6 to 50 carbon atoms (preferably 8 to 20 carbon atoms, such as methyl chloride, dimethyl sulfate, benzyl chloride and dimethyl carbonate), for example, dimethyl Examples include quaternized products of aminoethyl (meth) acrylate, quaternized products of diethylaminoethyl (meth) acrylate, quaternized products of dimethylaminoethyl (meth) acrylamide, and quaternized products of diethylaminoethyl (meth) acrylamide.
(A7) Polyether group-containing vinyl monomer:
Alkoxy (alkoxy group having 1 to 8 carbon atoms) polyalkylene (alkylene group having 2 to 4 carbon atoms) glycol mono (meth) acrylate [methoxypolyethylene glycol (degree of polymerization 2 to 40) mono (meth) acrylate and methoxypolypropylene glycol ( Polymerization degree 2-30) mono (meth) acrylate, etc.].

  Among the hydrophilic group-containing vinyl monomers (a), the hydroxyl group-containing vinyl monomer (a1) and the carboxyl group-containing vinyl monomer (a2), particularly (a2) are preferred from the viewpoint of imparting sufficient developability.

  Examples of the hydrophobic group-containing vinyl monomer (b) include the following nonionic monomers (b1) to (b6).

(B1) (meth) acrylic acid ester;
C1-C20 alkyl (meth) acrylate of an alkyl group [for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, n-hexyl (meth) acrylate and 2-ethylhexyl (meth) acrylate, etc.]; alicyclic group-containing (meth) acrylate [dicyclopentanyl (meth) acrylate, sidiclopentenyl (meth) acrylate, isobornyl (meth) acrylate, etc. ];

(B2) an aromatic hydrocarbon monomer;
And hydrocarbon monomers having a styrene skeleton [for example, styrene, α-methylstyrene, vinyltoluene, 2,4-dimethylstyrene, ethylstyrene, isopropylstyrene, butylstyrene, phenylstyrene, cyclohexylstyrene, and benzylstyrene] and vinylnaphthalene. It is done.
(B3) carboxylic acid vinyl ester;
Examples thereof include those having 4 to 50 carbon atoms, such as vinyl acetate, vinyl propionate and vinyl butyrate.
(B4) vinyl ether monomers;
Those having 3 to 50 (preferably 6 to 20) carbon atoms such as vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, vinyl butyl ether and the like can be mentioned.
(B5) vinyl ketone monomer;
Examples thereof include those having 4 to 50 carbon atoms, such as vinyl methyl ketone, vinyl ethyl ketone, and vinyl phenyl ketone.
(B6) a halogen atom-containing monomer;
Examples thereof include those having 2 to 50 (preferably 2 to 20) carbon atoms, such as vinyl chloride, vinyl bromide, vinylidene chloride, chlorostyrene and bromostyrene.

  Of the hydrophobic group-containing vinyl monomers (b), preferred is (b1) from the viewpoint of photocuring reactivity, and more preferred is an alicyclic group-containing (meth) acrylate.

  The charged monomer molar ratio of (a) / (b) in the hydrophilic vinyl polymer (A1) is usually from 10/90 to 100/0, preferably from 10/80 to 90 / from the viewpoint of photocurability and developability. 20, more preferably 25/75 to 85/15.

(A1) may contain a (meth) acryloyl group in the side chain for the purpose of further improving photocurability in the polymer having (a) and, if necessary, (b) as a constituent monomer. .
Examples of the method of incorporating a (meth) acryloyl group in the side chain include the following methods (1) and (2).
(1) A polymer is produced using a monomer having a group (such as a hydroxyl group or a primary or secondary amino group) capable of reacting with an isocyanate group in at least a part of the hydrophilic group-containing vinyl monomer (a), Thereafter, a method of reacting a compound having a (meth) acryloyl group and an isocyanate group (such as acryloylethyl isocyanate).
(2) A polymer using a monomer having a group capable of reacting with an epoxy group (hydroxyl group, carboxyl group, primary or secondary amino group, etc.) in at least a part of the hydrophilic group-containing vinyl monomer (a). A method of producing and then reacting a compound (glycidyl acrylate, etc.) having a (meth) acryloyl group and an epoxy group.

  The number average molecular weight (hereinafter abbreviated as Mn) of (A1) by gel permeation chromatography is preferably 500 to 500,000, from the viewpoint of photocurability and developability as the photosensitive resin composition, Preferably it is 1,000-100,000, Most preferably, it is 3,000-20,000.

(A1) can be obtained by performing polymerization with a radical polymerization initiator after the monomer is diluted with a solvent (E4) as necessary.
Solvents (E4) include glycol ethers (such as ethylene glycol monoalkyl ether and propylene glycol monoalkyl ether), ketones (such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone), and esters (butyl acetate, ethylene glycol alkyl). Ether acetate and propylene glycol alkyl ether acetate). Of (E4), ketones and esters are preferred.

  When the solvent (E4) is used, the amount used is not particularly limited, but is usually 1 to 400% based on the weight of the hydrophilic resin (A) (in the following,% represents% by weight unless otherwise specified). , Preferably 5 to 300%, particularly preferably 10 to 200%.

  Examples of the radical polymerization initiator include peroxides and azo compounds. Peroxides include inorganic peroxides (eg, hydrogen peroxide, ammonium persulfate, potassium persulfate, sodium persulfate, etc.) and organic peroxides (eg, benzoyl peroxide, di-t-butyl peroxide, Cumene hydroperoxide, lauryl peroxide, etc.). Examples of the azo compound include azobis (2,4-dimethylvaleronitrile), azobisisobutyronitrile, azobis (2-methylbutyronitrile), azobiscyanovaleric acid and its salts (for example, hydrochloride), and azobis (2 -Amidinopropane) hydrochloride and the like. Preferred is an azo compound. As a usage-amount of a polymerization initiator, 0.0001-20% is preferable normally based on the total weight of a monomer, More preferably, it is 0.001-15%, Most preferably, it is 0.005-10%. The reaction temperature and reaction time are appropriately determined depending on the type of radical polymerization initiator.

  As described above, the hydrophilic index of (A) is defined by HLB, and the HLB value of the hydrophilic group-containing vinyl monomer (A1) is preferably 9 to 19, more preferably 10 to 18, particularly Preferably it is 11-17. If the HLB of (A1) is 9 or more, developability can be further improved.

  The hydrophilic epoxy polymer (A2) in (A) in the present invention is a polymer having an epoxy resin skeleton containing a hydrophilic functional group such as a hydroxyl group or a carboxyl group. (A2) preferably has a (meth) acryloyl group in the molecule from the viewpoint of photocurability.

A preferred method for producing the hydrophilic epoxy polymer (A2) is to react the epoxy group in the epoxy resin (A2 ₀ ) with a (meth) acryloyl group-containing monocarboxylic acid to open the epoxy group to form a hydroxyl group. In this method, a polyvalent carboxylic acid or polyvalent carboxylic acid anhydride (e) is reacted with a part of the hydroxyl group.

Examples of (A2 ₀ ) include aliphatic epoxy resins [for example, Epototo YH-300, PG-202, PG-207 (all manufactured by Toto Kasei Co., Ltd.)] and alicyclic epoxy resins [for example, CY-179, CY. -177, CY-175 (both manufactured by Asahi Kasei Epoxy Co., Ltd.)] and aromatic epoxy resins [eg, phenol novolac epoxy resin, cresol novolac epoxy resin, bisphenol A epoxy resin, biphenyl type epoxy resin and glycidyl modified polyvinyl Phenol, etc.]. (A2 ₀₎ is preferred among aromatic epoxy resin from the viewpoint of curability.

  Examples of the (meth) acryloyl group-containing monocarboxylic acid used for the production of (A2) include acrylic acid and methacrylic acid.

  Examples of the polyvalent carboxylic acid and polyvalent carboxylic acid anhydride (e) used in the production of (A2) include unsaturated polyvalent carboxylic acids and their anhydrides among the aforementioned hydrophilic group-containing vinyl monomers (a). And saturated polyvalent (2-6 valent) carboxylic acids (eg oxalic acid, succinic acid, phthalic acid, adipic acid, dodecanedioic acid, dodecenyl succinic acid, pentadecenyl succinic acid and octadecenyl succinic acid) Aromatic saturated polycarboxylic acids; tetrahydrophthalic acid, hexahydrophthalic acid, methyltetrahydrophthalic acid, trimellitic acid, pyromellitic acid, biphenyltetracarboxylic acid and naphthalenetetracarboxylic acid, etc.) and their Anhydrides such as succinic anhydride, dodecenyl succinic anhydride, pentadecenyl succinic anhydride and octa Aliphatic saturated polycarboxylic anhydrides such as senyl succinic anhydride; phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, biphenyltetracarboxylic acid And aromatic polyvalent carboxylic acid anhydrides such as naphthalenetetracarboxylic acid anhydride). A saturated polycarboxylic acid anhydride is preferable from the viewpoint of reactivity and developability.

In the production of (A2), the charged weight ratio of (meth) acrylic acid / epoxy resin (A2 ₀ ) is preferably such that the concentration of (meth) acryloyl groups in (A2) is 1.0 mmol / g or more. It is a charged weight ratio of (meth) acrylic acid. From the above viewpoint, the weight ratio of acrylic acid / epoxy resin (A2 ₀ ) is preferably 0.072 or more / 1, and more preferably 0.079 to 0.72 / 1. The weight ratio of methacrylic acid is preferably 0.092 or more / 1, more preferably 0.10 to 0.92 / 1, from the above viewpoint.

The reaction temperature in the reaction of the epoxy resin (A2 ₀ ) and (meth) acrylic acid is not particularly limited, but is preferably 70 to 110 ° C. The reaction time is not particularly limited, but is preferably 5 to 30 hours.
Further, if necessary, a catalyst (for example, triphenylphosphine) and a radical polymerization inhibitor (hydroquinone, p-methoxyphenol, etc.) may be used.
Further, with respect to the weight of (A2 ₀₎ of (meth) acrylic acid adduct, charged equivalent of polycarboxylic acid or polycarboxylic acid anhydride (e) is the acid value of the (A2), preferably 10~500mgKOH For example, when (e) is a divalent carboxylic acid or its anhydride, (e) is equivalent to (e) charged equivalent / (A2 ₀ ) (meth) acrylic acid From the above viewpoint, the weight of the adduct is preferably 0.18 to 8.9 meq / g, and more preferably 0.53 to 7.1 meq / g.

The reaction temperature in the reaction of the (meth) acrylic acid adduct of (A2 ₀ ) with the polyvalent carboxylic acid or polyvalent carboxylic anhydride (e) is not particularly limited, but is preferably 70 to 110 ° C. The reaction time is not particularly limited, but is preferably 3 to 10 hours.

  Mn of (A2) is usually 500 to 3,000, preferably 1,000 to 2,800, particularly preferably 1,500 to 2, from the viewpoint of elastic recovery characteristics and developability as the photosensitive resin composition. 500.

  The HLB value of (A2) is preferably 4 to 14, more preferably 5 to 13, and particularly preferably 6 to 12. If the HLB of (A2) is 4 or more, the developability can be satisfactorily exhibited.

  Of the hydrophilic resins (A), the epoxy polymer (A2) is particularly preferable from the viewpoint of elastic recovery characteristics of the photosensitive resin composition and the ease of production, and particularly preferable is phenol. It is a hydrophilic resin containing a (meth) acryloyl group and a carboxyl group obtained by modifying a novolac epoxy resin or a cresol novolac epoxy resin.

  As the polyfunctional (meth) acrylate monomer (B) which is an essential component of the present invention, any known polyfunctional (meth) acrylate monomer can be used without particular limitation, and bifunctional (meth) acrylate (B1). A trifunctional (meth) acrylate (B2) and a 4-6 functional (meth) acrylate (B3) are mentioned.

  Examples of the bifunctional (meth) acrylate (B1) include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, and polyethylene glycol di (meth). Acrylate, polypropylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, glycerin di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, 1,10-decanediol di (meth) acrylate, 3-methyl-1,5-pentanediol di (meth) acrylate, 2-butyl-2-ethyl- , 3-propanediol di (meth) acrylate, dimethylol-tricyclodecane di (meth) acrylate, di (meth) acrylate of bisphenol A ethylene oxide adduct, di (meth) acrylate of propylene oxide adduct of bisphenol A, Examples thereof include hydroxypivalic acid neopentyl glycol di (meth) acrylate and the like.

  As trifunctional (meth) acrylate (B2), glycerin tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, tri (meth) acrylate of trimethylolpropane ethylene oxide adduct Etc. are exemplified.

  Examples of the 4-6 functional (meth) acrylate (B3) include pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate and the like.

  Preferred among the polyfunctional (meth) acrylate monomer (B) are (B2) and (B3), more preferably dipentaerythritol pentaacrylate, pentaerythritol triacrylate, and combinations thereof. As (B) which can be easily obtained from the market, for example, Aronix M-403 (manufactured by Toagosei Co., Ltd.), light acrylate PE-3A (manufactured by Kyoeisha Chemical Co., Ltd.), neomer DA-600 (Sanyo Chemical Industries ( Etc.).

  The liquid polybutadiene copolymer (C) of the present invention, which is an essential component of the present invention, is a copolymer containing an acrylonitrile component (x) and a butadiene component (y), and the structure of butadiene is vinyl 1,2-bond. It is a liquid polymer that is transparent at room temperature, consisting of a mold, a trans 1,4-bond type, and a cis 1,4-bond type.

Furthermore, other polymerizable monomers that can be copolymerized may be contained.
Other polymerizable monomers are not particularly limited as long as they are copolymerizable, and examples thereof include olefinic hydrocarbons having 2 to 12 carbon atoms such as ethylene, propylene, and butene; styrene, α-methylstyrene, chloromethylstyrene, and the like. Aromatic monomers such as vinylphenol; C1-C12 (meth) acrylic acid alkyl ester monomers such as methyl (meth) acrylate, ethyl (meth) acrylate and butyl (meth) acrylate; (meth) Acrylamide monomers such as acrylamide and alkyl-substituted (meth) acrylamides; alkyl vinyl ether monomers having 1 to 8 carbon atoms of alkyl groups such as methyl vinyl ether; carboxylic acid vinyl esters having 2 to 12 carbon atoms of carboxylic acids such as vinyl acetate Monomers and the like are used.
These can be used alone or in combination of two or more.
Of these, aromatic monomers are preferable from the viewpoint of heat resistance, and styrene is more preferable from the viewpoint of copolymerization.

The liquid polybutadiene copolymer (C), which is one of the essential components of the photosensitive resin composition (Q) of the present invention, contains 10 to 50% by weight of the acrylonitrile component (x). From the viewpoint of transparency, it is usually 10 to 50% by weight, preferably 15 to 45% by weight, and more preferably 20 to 35% by weight.
Such a liquid polybutadiene copolymer (C) containing a certain amount of acrylonitrile component can be easily obtained commercially, for example, CTBN 1300 × 8, CTBN 1300 × 9, CTBN 1300 × 13 (all Ube Industries) Etc.).

  Mn of (C) is usually 500 to 7,000, preferably 1,000 to 5,000, particularly preferably 1,500 to 4, from the viewpoint of elastic recovery characteristics and developability as the photosensitive resin composition. 000.

Further, (C) preferably has at least one functional group selected from an epoxy group, a hydroxyl group, an isocyanate group, and a carboxyl group. Among the above, a carboxyl group is preferable from the viewpoint of developability.
The position of these functional groups may be the end of the main chain or the side chain of the liquid polybutadiene copolymer (C).

The radical photopolymerization initiator (D) used as one essential component in the photosensitive resin composition (Q) of the present invention is not particularly limited as long as it is a radical photopolymerization initiator usually used in this application.
For example, benzyl dimethyl ketal, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzophenone, methyl benzoyl formate, isopropyl thioxanthone, 4,4-bis (dimethylamino) benzophenone 3,3-dimethyl-4-methoxy-benzophenone, anthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, tert-butylanthraquinone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, acetophenone, 2,2- Dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, 2-hydroxy-2-methylpropiophenone, 4-isopropyl-2-hydride Xyl-2-methylpropiophenone, 2-methyl-1- (4- (methylthio) phenyl) -2-morpholino-1-propanone, 2-chlorothioxanthone, diethylthioxanthone, isopropylthioxanthone, diisopropylthioxanthone, Michler's ketone, benzyl- 2,4,6- (trihalomethyl) triazine, 2- (o-chlorophenyl) -4,5-diphenylimidazolyl dimer, 9-phenylacridine, 1,7-bis (9-acridinyl) heptane, 1,5- Bis (9-acridinyl) pentane, 1,3-bis (9-acridinyl) propane, dimethylbenzyl ketal, trimethylbenzoyldiphenylphosphine oxide, bistrimethylbenzoylphenylphosphine oxide, tribromomethylphenyls Hong and 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) - butan-1-one, and the like. (C) may be used alone or in combination of two or more.

  (D) can be easily obtained commercially, for example, Irgacure 819 as bistrimethylbenzoylphenylphosphine oxide, Darocur TPO (produced by Ciba Specialty Chemicals) as trimethylbenzoyldiphenylphosphine oxide, etc. Is mentioned.

Although the photosensitive resin composition (Q) may contain a solvent as necessary, the content of the hydrophilic resin (A) in the weight of the solid content is preferably 20 to 70% by weight, more preferably. 25 to 65% by weight. If it is 70% by weight or less, the photocurability is further improved. The content of the polyfunctional acrylate monomer (B) in the solid content of the photosensitive resin composition (Q) is 10 to 60% by weight. More preferably, it is 15-5 weight 5%. If it is 55% by weight or less, the developability is further improved.
The content of the liquid polybutadiene copolymer (C) in the weight of the solid content of the photosensitive resin composition (Q) is preferably 5 to 50% by weight, and more preferably 10 to 40% by weight. When it is 50% by weight or less, the photocurability is further improved.
The content of the photo radical polymerization initiator (D) in the weight of the solid content of the photosensitive resin composition (Q) is preferably 0.01 to 10% by weight, more preferably 0.5 to 8% by weight. is there. If it is 10% by weight or less, the developability is further improved.

The photosensitive resin composition (Q) may further contain other components (E) as necessary.
As other components (E), inorganic fine particles (E1), sensitizers (E2), polymerization inhibitors (E3), solvents (E4), and other additives (E5) (for example, inorganic pigments, silane cups) Ring agents, dyes, fluorescent whitening agents, yellowing inhibitors, antioxidants, antifoaming agents, deodorants, fragrances, bactericides, antibacterial agents and fungicides, and the like.

  As the inorganic fine particles (E1), metal oxides and metal salts can be used. Examples of the metal oxide include titanium oxide, silicon oxide, and aluminum oxide. Examples of the metal salt include calcium carbonate and barium sulfate. Of these, metal oxides are preferable from the viewpoint of heat-resistant transparency and chemical resistance, and silicon oxide and titanium oxide, and particularly silicon oxide are more preferable. The inorganic fine particles have a volume average primary particle diameter of 1 to 200 nm, preferably from 1 to 150 nm, more preferably from 1 to 120 nm, and particularly preferably from 5 to 20 nm, from the viewpoint of transparency.

  The content of (E1) in the weight of the solid content of the photosensitive resin composition (Q) is usually 0 to 50%, preferably 0 to 45%, particularly preferably 0 to 40%. If it is 50% or less, the developability can be further improved, and if it is 0 to 40%, the elastic recovery property of the cured product is particularly excellent.

  As the sensitizer (E2), nitro compounds (for example, anthraquinone, 1,2-naphthoquinone, 1,4-naphthoquinone, benzanthrone, p, p'-tetramethyldiaminobenzophenone, carbonyl compounds such as chloranil, nitrobenzene, p -Dinitrobenzene and 2-nitrofluorene etc.), aromatic hydrocarbons (eg anthracene and chrysene etc.), sulfur compounds (eg diphenyl disulfide etc.) and nitrogen compounds (eg nitroaniline, 2-chloro-4-nitroaniline) , 5-nitro-2-aminotoluene, tetracyanoethylene and the like.

  The content of the sensitizer (E2) based on the weight of the radical photopolymerization initiator (D) is usually 0 to 100%, preferably 0 to 80%, particularly preferably 0 to 70%.

  There is no limitation in particular as a polymerization inhibitor (E3), What is used for normal reaction is used. Specifically, diphenylhydrazyl, tri-p-nitrophenylmethyl, N- (3-N-oxyanilino-1,3-dimethylbutylidene) aniline oxide, p-benzoquinone, p-tert-butylcatechol, nitrobenzene, Examples include picric acid, dithiobenzoyl disulfide, and copper (II) chloride.

  The content of the polymerization inhibitor (E3) in the weight of the solid content of the photosensitive resin composition (Q) is preferably 0 to 1.0%, more preferably 0 to 0.5%, particularly preferably 0. ~ 0.1%.

As a solvent (E4), the thing similar to the solvent used for manufacture of the above-mentioned hydrophilic resin (A) can be used.
When the solvent is used, the amount of the solvent is not particularly limited, but is preferably 30 to 90%, more preferably 30 to 80%, of the weight of the photosensitive resin composition (Q) including the solvent. . In addition, the solvent used for manufacture of above-mentioned (A) and (B) is also contained in the compounding quantity of a solvent.

The photosensitive resin composition (Q) of the present invention can be obtained, for example, by mixing the above-described components with a known mixing device such as a planetary mixer.
Moreover, the photosensitive resin composition is normally liquid at room temperature, and the viscosity is 0.1-100 mPa * s at 25 degreeC, Preferably it is 1-20 mPa * s. However, if it becomes liquid by raising the temperature, it does not matter even if it is not liquid at room temperature.

  The photosensitive resin composition (Q) of the present invention is excellent in developability, and its cured product is excellent in flexibility, elastic recovery characteristics and adhesion, so that it particularly has a photosensitivity for forming a photo spacer in a liquid crystal cell. Suitable as a resin composition.

Hereinafter, the photo spacer provided in the liquid crystal cell of the present invention will be described.
The photo spacer of the present invention is a member provided for forming a gap in the liquid crystal cell, and is formed by curing the photosensitive resin composition (Q) by a process including light irradiation.

A preferable formation step of the photospacer of the present invention is a step of performing pattern development by alkali development after light irradiation, and further performing post-baking at 180 to 260 ° C. for 5 to 90 minutes.
The formation of the protrusion is usually performed in the following steps (1) to (5).

(1) The process of apply | coating the photosensitive resin composition of this invention on a transparent common electrode As a coating method, a roll coat, a spin coat, a spray coat, a slit coat, etc. are mentioned.
Examples of the coating apparatus include a spin coater, an air knife coater, a roll coater, a bar coater, a curtain coater, a gravure coater, and a comma coater.
The film thickness is usually 0.5 to 10 μm, preferably 1 to 5 μm.

(2) Step of drying the applied photosensitive resin composition layer by applying heat as necessary (prebaking) The drying temperature is preferably 10 to 100 ° C., more preferably 12 to 90 ° C., particularly 15 ~ 60 ° C, especially 20-50 ° C.
The drying time is preferably 0.5 to 10 minutes, more preferably 1 to 8 minutes, and particularly preferably 2 to 5 minutes.
Drying may be performed under reduced pressure or normal pressure, but reduced pressure is preferred. Moreover, although it may carry out in air or in an inert gas, it is preferably in an inert gas.

(3) Step of exposing the photosensitive resin composition layer with actinic rays through a predetermined photomask The size of the opening of the photomask used is preferably 4 to 15 μm in diameter (area 20 to 100 μm 2). More preferably, the diameter is 6 to 12 μm, and if it is 4 to 15 μm, the pattern can be formed with high accuracy. For example, if the opening has a diameter of 4 to 15 μm, a pattern with a diameter of about 6 to 18 μm can be obtained.
Examples of the active light include visible light, ultraviolet light, and laser light. Examples of the light source include sunlight, a high-pressure mercury lamp, a low-pressure mercury lamp, a metal halide lamp, and a semiconductor laser.
Although it does not specifically limit as an exposure amount, Preferably it is 20-300 mJ / cm < ² >.
In the step of performing exposure, a component having a (meth) acryloyl group in the photosensitive resin composition reacts to undergo photocuring reaction.

(4) Subsequently, the step of removing the unexposed portion with a developer and performing development. Usually, an alkaline aqueous solution is used as the developer.
Examples of the alkaline aqueous solution include aqueous solutions of alkali metal hydroxides such as sodium hydroxide and potassium hydroxide; aqueous solutions of carbonates such as sodium carbonate, potassium carbonate and sodium hydrogencarbonate; hydroxytetramethylammonium and hydroxytetraethylammonium. An aqueous solution of an organic alkali can be mentioned. These can be used alone or in combination of two or more kinds, and a surfactant such as an anionic surfactant, a cationic surfactant, an amphoteric surfactant and a nonionic surfactant can be added and used.
As a developing method, there are a dip method and a shower method, but the shower method is preferable.
The temperature of the developer is preferably 25 to 40 ° C. The development time is appropriately determined according to the film thickness and the solubility of the photosensitive resin composition.

(5) Post-heating (post-baking) step The post-baking temperature is preferably 180 to 260 ° C, more preferably 190 to 250 ° C, and particularly preferably 200 to 240 ° C.
The post-baking time is 5 minutes to 90 minutes, preferably 15 minutes to 75 minutes, and particularly preferably 30 minutes to 60 minutes.
The baking may be performed under reduced pressure or normal pressure, but normal pressure is preferred. Moreover, although it may carry out in air or in an inert gas, the air is preferable.
By performing post-baking, the shape of the pattern tends to be a preferable shape and size (for example, a height of 1.0 to 6.0 μm and a lower base diameter of 8.0 to 40.0 μm) as a photo spacer.
In the post-heating step, it is presumed that a component having a thermosetting functional group in the photosensitive resin composition reacts and is thermoset. Examples of the thermosetting reactive group include a trace amount of a (meth) acryloyl group remaining in the exposure step among the (meth) acryloyl groups in (A).

  The height of the photo spacer formed by the above process is 1.0 to 6.0 μm, preferably 1.5 to 5.5 μm, and particularly preferably 2.0 to 5.0 μm.

  The above process makes it easy to control the shape and size (height, upper base diameter, lower base diameter), and stable and highly productive photo spacers with excellent pattern shape, heat resistance, solvent resistance, and transparency. Can be formed.

  The photospacer of the present invention obtained as described above is a photospacer excellent in flexibility and elastic recovery characteristics. The flexibility of the photo spacer can be evaluated by “total deformation amount” and “elastic recovery characteristics” when a delicate pressure is applied. A larger total deformation amount and a larger elastic recovery characteristic are more flexible. The elastic recovery characteristic of the photospacer can be evaluated by “total deformation amount” and “plastic deformation amount” when pressure is applied. The larger the total deformation amount and the smaller the plastic deformation amount, the better the elastic recovery characteristics.

  In the present invention, the flexibility and elastic recovery characteristics can be evaluated by measuring the following “total deformation amount, elastic recovery rate in a pressure range of 0.2 to 0.8 mN / μm 2”.

Measuring method of “total deformation (μm)” and “elastic recovery rate (%)”;
At 25 ° C., a predetermined pressure is applied at a constant speed, held for one second, and then the total deformation amount T ₀ (from the hysteresis curve (FIG. 1) between the load and the deformation amount when the pressure is unloaded at a constant speed. μm) is obtained, and the plastic deformation amount T ₁ (μm) is obtained, and the elastic recovery rate (%) at a predetermined pressure is calculated by the following equation.
Elastic recovery rate (%) = [(T ₀ −T ₁ ) / T ₀ ] × 100
As the pressure, hysteresis curves are measured at four different pressures of 0.2 mN / μm 2, 0.4 mN / μm 2, 0.6 mN / μm 2, and 0.8 mN / μm 2, and the elastic recovery rate is obtained for each.
The “load and deformation amount hysteresis curve” will be described later with reference to the drawings.

  The total deformation amount of the photo spacer of the present invention is preferably 0.5 to 2.5 μm, more preferably 0.75 to 2.0 μm, and particularly preferably 1.0 to 1.5 μm under a pressure condition of 1.5 GPa. It is. If the total deformation amount is 0.5 μm or more, there is a high possibility that it can be used practically as a spacer for holding the liquid crystal cell gap.

  The elastic recovery rate of the photospacer of the present invention is preferably 60% or more, more preferably 65% or more, and particularly preferably 70% or more under a pressure condition of 1.5 GPa. If the elastic recovery rate is 60% or more, particularly 65% or more, there is a high possibility that it can be used as a spacer for retaining the liquid crystal cell gap without any practical problems.

  Hereinafter, although an example and a comparative example explain the present invention further, the present invention is not limited to these. Hereinafter, unless otherwise specified, “%” represents “% by weight” and “parts” represents “parts by weight”.

[Production of hydrophilic resin (A)]
<Production Example 1>
Glass Kolben equipped with heating / cooling / stirring measures, reflux condenser, dropping funnel and nitrogen inlet, cresol novolac epoxy resin “EOCN-102S” (Epoxy equivalent 200, Nippon Kayaku Co., Ltd.) and propylene 245 parts of glycol monomethyl ether acetate was charged and heated to 110 ° C. to dissolve uniformly. Subsequently, 76 parts of acrylic acid, 2 parts of triphenylphosphine, and 0.2 part of p-methoxyphenol were charged and reacted at 110 ° C. for 10 hours. The reaction product was further charged with 91 parts of tetrahydrophthalic anhydride, further reacted at 90 ° C. for 5 hours, and then diluted with propylene glycol monomethyl ether acetate to a solid content of 25%, having an acryloyl group and a carboxyl group. Propylene glycol monomethyl of hydrophilic resin (A-1) (Mn: 2,200, SP value: 11.26, HLB value: 6.42, acid value: 91 mgKOH / g, acryloyl group concentration: 2.86 mmol / g) An ether acetate solution was obtained (solid content 25%).
Mn is a value in terms of polystyrene measured by the GPC method using a GPC measuring device (HLC-8120GPC, manufactured by Tosoh Corporation) and a column (2 TSKgel GMHXL + TSKgel Multipore HXL-M, manufactured by Tosoh Corporation). As sought.
The SP value, HLB value, and acid value were determined as described above. The same measurement method is used for the following production examples and comparative examples.

<Production Example 2>
A glass Kolben equipped with a heating / cooling / stirring measure, a reflux condenser, a dropping funnel and a nitrogen inlet tube, isobornyl methacrylate 50 parts (33 mol%), 2-hydroxyethyl methacrylate 30 parts (33 mol%), methacryl 20 parts (34 mol%) of acid and 150 parts of cyclohexanenone were charged and heated to 80 ° C. A solution in which 5 parts of azobisisobutyronitrile (V-60: manufactured by Wako Pure Chemical Industries, Ltd., hereinafter referred to as AIBN) prepared in advance in 50 parts of cyclohexanone is prepared by substituting the gas phase part in the system with nitrogen. 55 parts were dropped into Kolben at 80 ° C. over 10 minutes, and further reacted at the same temperature for 3 hours to obtain a hydrophilic resin having a carboxyl group (A-2) (Mn: 8,800, SP value: 11.86, A cyclohexanone solution having an HLB value of 11.98 and an acid value of 102 mg KOH / g was obtained (the solid content was 25%).

<Comparative Production Example 1>
In the same Kolben as in Production Example 1, 200 parts of cresol novolac resin (EP-4020G manufactured by Asahi Organic Materials Co., Ltd.) and 238 parts of propylene glycol monomethyl ether acetate were charged and heated to 110 ° C. to be uniformly dissolved. Subsequently, 0.1 part of dibutyltin dilaurate and 20 parts of isocyanatoethyl methacrylate were added, reacted at 60 ° C. for 5 hours, and then diluted with propylene glycol monomethyl ether acetate to a solid content of 25%. Hydrophilic resin having an acryloyl group (A-1 ′) (Mn: 2,100, SP value: 13.46, HLB value: 6.41, acid value: 0 mgKOH / g, acryloyl group concentration: 1.34 mmol / A propylene glycol monomethyl ether acetate solution of g) was obtained (solid content 25%).

<Examples 1-5 and Comparative Examples 1-5>
[Production of photosensitive resin composition]
Number of blended parts in Table 1 [apparent parts by weight of each component, () is the weight% of the solid content of each component of the solid content of the photosensitive resin composition (Q) (rounded off to one decimal place) ). ], A glass container is charged with a solution of the hydrophilic resins (A-1) and (A-2), and the following polyfunctional acrylate monomers (B-1) and (B-2), liquid polybutadiene copolymer Combined (C-1), (C-2), (C-1 ′), (C-2 ′), radical photopolymerization initiators (D-1), (D-2) are charged until uniform. Stirring, and further adding an additional solvent, propylene glycol monomethyl ether acetate (E-1), photosensitive resin compositions (Q-1) to (Q-5) of Examples, and photosensitive resin compositions of Comparative Examples Products (Y-1) to (Y-5) were produced.
The abbreviations in Table 1 other than the above are as follows.

(B-1): “Neomer DA-600” (mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate: manufactured by Sanyo Chemical Industries, Ltd.)
(B-2): “DPCA-20” (polycaprolactone-modified dipentaerythritol hexaacrylate: manufactured by Nippon Kayaku Co., Ltd.),
(C-1): “CTBN 1300 × 9” (butadiene-acrylonitrile copolymer, acrylonitrile content 17%: manufactured by Ube Industries, Ltd.)
(C-2): “CTBN 1300 × 13” (butadiene-acrylonitrile copolymer, acrylonitrile content 27%: manufactured by Ube Industries, Ltd.)
(C-1 ′): “CTBN 1300 × 31” (butadiene / acrylonitrile copolymer, acrylonitrile content 10%: manufactured by Ube Industries, Ltd.)
(C-2 ′): “CTBN 2000 × 162” (butadiene homopolymer, acrylonitrile content 0%: manufactured by Ube Industries, Ltd.)
(D-1): “Irgacure 819” (bistrimethylbenzoylphenylphosphine oxide: manufactured by Ciba Specialty Chemicals),
(D-2): “Irgacure 369” (2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone-1: manufactured by Ciba Specialty Chemicals),

[Evaluation of developability]
The photosensitive resin compositions (Q-1) to (Q-5) and (Y-1) to (Y-5) were respectively spin-coated on a glass substrate so that the finished film thickness was 5 μm. Dry at 5 ° C. for 5 minutes.
Thereafter, development was performed for 45 seconds using a 0.05% aqueous potassium hydroxide solution, and the developability was visually evaluated. The results are shown in Table 1.
The evaluation criteria are as follows.
A: No residue at all.
○: There is a slight residue.
Δ: There are many residues.
×: A pattern cannot be created.

<Examples 6 to 10 and Comparative Examples 6 to 10>
[Production of photo spacer]
Finish the photosensitive resin compositions (Q-1) to (Q-5) and (Y-1) to (Y-5) on glass substrates formed with ITO (indium oxide doped with tin), respectively. It spin-coated so that a film thickness might be set to 2 micrometers, and dried for 5 minutes at 25 degreeC. The light from a high-pressure mercury lamp was irradiated through a photomask at 100 mJ / cm2. Note that the exposure (gap) between the photomask and the substrate was 100 μm.
Thereafter, development was performed using a 0.05% aqueous potassium hydroxide solution. Photo-spacers (R-1) to (R-5) and (Z-1) to (Z-1) having ITO films formed on a glass substrate by post-baking at 230 ° C. for 30 minutes after washing with water. -5) was produced. The upper base area of the photo spacer was 150 μm ² and the lower base area was 400 μm ² .

[Measurement of total deformation and elastic recovery rate]
The total deformation amount and elastic recovery rate of the photo spacer obtained as described above were measured using a Fischer scope H-100 (Fischer Instruments) apparatus.
A flat indenter (50 μm × 50 μm) having a square cross section was used. The results are shown in Table 2.

Examples 11-15 and Comparative Examples 11-15
[Preparation of cured coating film]
The photosensitive resin compositions (Q1) to (Q5) and (Y1) to (Y5) were each spin-coated on a glass substrate so that the finished film thickness was 3 μm, and the light from the high-pressure mercury lamp was 100 mJ over the entire surface. / Cm 2 irradiation. Note that the exposure (gap) between the photomask and the substrate was 100 μm. Then, it post-baked at 230 degreeC for 60 minute (s), and produced the cured coating films (S-1)-(S-5) and (W-1)-(W-5).

[Measurement of adhesion]
Cut the 1 mm width with the knife into the cured coating film obtained above to make a grid (10 × 10), apply cellophane adhesive tape on the grid and peel it 90 degrees, The peeled state of the cured product (film) was observed and evaluated. The results are shown in Table 3.
○ All grids do not peel. △ 1-10 grids peel. × 11 grids or more peel.

[Measurement of transparency]
The cured coating film obtained above was measured for light transmittance at a wavelength of 400 nm using a UV transmittance meter (UV2400PC, manufactured by Shimadzu Corporation). The results are shown in Table 3.

As can be seen from Table 1, Table 2, and Table 3, by using the photosensitive resin composition of the present invention, developability is good, and flexibility (total deformation amount), elastic recovery characteristics (elastic recovery rate) A photo spacer having excellent adhesion and transparency can be formed.
On the other hand, in the comparative example 1 which does not use a hydrophilic polymer, it is inferior to developability. In Comparative Examples 2 and 3 where the liquid polybutadiene does not contain a sufficient amount of the acrylonitrile component, the transparency is poor. In Comparative Example 4 in which no rubber component is used, the flexibility and adhesion are inferior. In Comparative Example 5, the polyfunctional (meth) acrylate monomer is not used and the elastic recovery characteristic is inferior. When a liquid crystal panel is produced using such a photo spacer, the display quality is not uniformed. Gets worse. In addition, it is difficult to maintain display quality for a long time.

The photosensitive resin composition of this invention can be used conveniently for the photo spacer in a liquid crystal cell.
In addition, it is also suitable as a photosensitive resin composition for uses such as various resist materials such as a photo solder resist, a photosensitive resist film, a photosensitive resin relief plate, a screen plate, a photoadhesive or a hard coat agent.
Furthermore, coating agents for various materials such as metals (for example, iron, aluminum, titanium, copper, etc.), plastics (for example, polycarbonate, polyethylene terephthalate, poly (meth) acrylate), paper, glass, rubber and wood, paints, It can also be used as a printing ink and an adhesive, and can also be applied as a molding material.

Hysteresis curve of load and deformation

Explanation of symbols

T0: Total deformation amount T1: Plastic deformation amount T2: Elastic deformation amount

Claims (5)

  A photosensitive resin composition (Q) containing a hydrophilic resin (A) having a carboxyl group, a polyfunctional acrylate monomer (B), a liquid polybutadiene copolymer (C), and a radical photopolymerization initiator (D). The liquid polybutadiene copolymer (C) contains the acrylonitrile component (x) in an amount of 10 to 50% by weight based on the weight of the liquid polybutadiene copolymer (C), and the photosensitive resin composition (Q). The alkali-developable photosensitive resin composition (Q), wherein a 400 nm light transmittance of a cured film on a glass substrate formed by photocuring is 90% or more.   The photosensitive resin composition of Claim 1 in which this liquid polybutadiene copolymer (C) contains a carboxyl group.   The photosensitive resin composition according to claim 1 or 2, wherein the hydrophilic resin (A) further contains a (meth) acryloyl group.   Based on the weight of the solid content of the photosensitive resin composition (Q), the hydrophilic resin (A) is 20 to 70% by weight, the polyfunctional acrylate monomer (B) is 10 to 60% by weight, and the liquid polybutadiene is co-polymerized. The photosensitive resin composition in any one of Claims 1-3 which contains 5 to 50 weight% of polymers (C), and 0.01 to 10 weight% of radical photopolymerization initiators (C). The photo-spacer provided in the liquid crystal cell formed by hardening the photosensitive resin composition (Q) in any one of Claims 1-4 by the process including light irradiation.

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