JP6289816B2 - Photosensitive resin composition - Google Patents

Description

  The present invention relates to a photosensitive resin composition, and a spacer, an insulating film, and a protective film formed from the composition.

  In recent years, liquid crystal display devices have attracted attention, and photosensitive resins are frequently used in the manufacturing process. For example, a photosensitive resin in which a color pigment is dispersed is used for a portion corresponding to a pixel on a color filter, and a photosensitive resin is also used for a black matrix.

  Conventionally, in a liquid crystal display panel, beads having a predetermined particle diameter are used as a photo spacer to provide a gap between two substrates. However, since these beads are dispersed randomly, there is a problem that light leakage, scattering of incident light, etc. occur due to distribution on the color display pixels, and the contrast of the liquid crystal panel is lowered.

  In order to solve these problems, a method has been proposed in which a columnar resinous spacer is formed on a black matrix located between pixels by a photolithographic method of partial pattern exposure and development using a photosensitive resin. . Since the photo spacer can be arranged at a position avoiding the pixels, it does not adversely affect the display quality as described above, and the display quality can be improved.

In order to further improve display quality, higher definition of the photo spacer is desired. However, with the increase in definition, there has been a phenomenon in which the elastic recovery characteristic is lowered, and further, the adhesion with the substrate is lowered and the photo spacer is peeled off.
As a high definition method, a method of adding a sulfur atom-containing compound (for example, Patent Document 1) is disclosed. However, when a fine photospacer is formed, the adhesion is remarkably lowered.

On the other hand, in recent years, a drop method (ODF: One Drop Fill) has been proposed in place of the conventional liquid crystal inflow method (vacuum suction method) as the mother glass for manufacturing a liquid crystal display (LCD) becomes larger. ing. In this ODF method, since a predetermined amount of liquid crystal is dropped and then liquid crystal is injected by being sandwiched between two substrates, the number of steps and the process time can be reduced as compared with the conventional vacuum suction method.
However, in the ODF system, a predetermined amount of liquid crystal calculated from the cell gap is dropped and held, so that a pressure change is applied to the photo spacer arranged on the glass substrate. It is desired for the photo spacer to have a high elastic recovery characteristic so that the shape does not plastically deform with respect to this pressure change.

In order to obtain such high elastic recovery characteristics, a method of nano-dispersing inorganic fine particles such as organosilica sol (for example, Patent Document 2), or a content ratio of a polyfunctional monomer such as dipentaerythritol hexaacrylate is 50% or more. A method (for example, Patent Document 3) is known in which high elasticity is obtained by increasing the thickness.
However, in any method, since the adhesiveness between the photo spacer and the substrate such as glass is lowered, a photosensitive resin composition capable of achieving both high elasticity and sufficient adhesiveness has not been obtained.

Japanese Patent Laid-Open No. 10-274853 Japanese Patent Laid-Open No. 2007-10885 JP 2002-174812 A

  An object of this invention is to provide the photosensitive resin composition in which hardened | cured material has the elastic recovery characteristic and adhesiveness which were excellent, and can form a high-definition spacer.

［式（２）中、Ｒ ^３ とＲ ^４ はそれぞれ独立にアルキル基、（メタ）アクリロイル基または（メタ）アクリロイロキシアルキル基であり、各官能基の炭素数は１〜２０である。Ｒ ^５ とＲ ^６ はそれぞれ独立にアルキル基、アルコキシ基、アリール基、メルカプトアルキル基、アミノアルキル基、（メタ）アクリロイル基、（メタ）アクリロイロキシアルキル基、（メタ）アクリロイロキシアルコキシ基または（メタ）アクリロイロキシ基であり、各官能基の炭素数は１〜２０である。繰り返し単位により１分子中にＲ ^５ とＲ ^６ が複数個含まれる場合はそれぞれ同一でも異なる基であってもよい。ただし、ｎ個のＲ ^５ とｎ個のＲ ^６ のうち、少なくとも１個はアルコキシ基である。ｎは１〜２０の整数である。］ The inventors of the present invention have reached the present invention as a result of studies to achieve the above object.
That is, the present invention is the following four inventions.
(I) Hydrophilic resin (A), polyfunctional (meth) acrylate (B), aromatic amine (C1), siloxane compound (E) represented by the following general formula (2), which contains at least one alkoxy group And a photopolymerization initiator (D) as an essential component .
(II ) A photo spacer, insulating film or protective film formed on the display element, color filter or panel by curing the photosensitive resin composition of (I ) .
( III ) A display element, a color filter or a panel comprising the photospacer, insulating film or protective film of ( II ).

[In Formula (2), R < ³ > and R < ⁴ > are respectively independently an alkyl group, a (meth) acryloyl group, or a (meth) acryloyloxyalkyl group, and carbon number of each functional group is 1-20. R ⁵ and R ⁶ are each independently an alkyl group, alkoxy group, aryl group, mercaptoalkyl group, aminoalkyl group, (meth) acryloyl group, (meth) acryloyloxyalkyl group, (meth) acryloyloxyalkoxy group or It is a (meth) acryloyloxy group, and each functional group has 1 to 20 carbon atoms. When a plurality of R ⁵ and R ⁶ are contained in one molecule by repeating units, they may be the same or different groups. However, at least one of n R ⁵ and n R ⁶ is an alkoxy group. n is an integer of 1-20. ]

  The photosensitive resin composition of the present invention has an effect that the cured product has excellent elastic recovery characteristics and adhesion, and can form a high-definition photospacer.

  The photosensitive resin composition of the first invention contains a hydrophilic resin (A), a polyfunctional (meth) acrylate (B), an aromatic amine (C1), and a photopolymerization initiator (D) as essential components. It is characterized by that. Further, a cured product such as a photospacer obtained by curing the photosensitive resin composition of the first and second inventions has excellent elastic recovery characteristics, excellent adhesion to a glass substrate, and a fine shape. Can be formed.

  In this specification, “(meth) acrylate” means “acrylate or methacrylate”, “(meth) acrylic acid” means “acrylic acid or methacrylic acid”, and “(meth) acrylic resin” means “ “Acrylic resin or methacrylic resin”, “(meth) acryloyl group” means “acryloyl group or methacryloyl group”, and “(meth) acryloyloxy group” means “acryloyloxy group or methacryloyloxy group”.

In the following, (A), (B), (C), and (D) [hereinafter referred to as (A) to (D), which are essential components of the photosensitive resin compositions of the first and second inventions] To do. ] Will be described in order. (C) means (C1) and / or (C2).
The hydrophilicity index in the hydrophilic resin (A) in the present invention is defined by HLB. Generally, the larger this value, the higher the hydrophilicity.
The HLB value of (A) is preferably 4 to 19, more preferably 5 to 18, and particularly preferably 6 to 17. When it is 4 or more, the developing property is further improved when developing the photospacer, and when it is 19 or less, the water resistance of the cured product is further improved.

Here, “HLB” is an index indicating a balance between hydrophilicity and lipophilicity, and is described in, for example, “Introduction to Surfactants” (published by Sanyo Chemical Industries, Ltd., 2007, Takehiko Fujimoto), page 212. It is known as the calculated value by the Oda method, not the calculated value by the Griffin method.
The HLB value can be calculated from the ratio between the organic value and the inorganic value of the organic compound.
HLB = 10 × inorganic / organic The organic value and the inorganic value for deriving HLB can be calculated using the values in the table described in the above “Introduction to Surfactant” page 213.

Further, the solubility parameter of the hydrophilic resin (A) (hereinafter, SP value of.) [(In ^{(cal / cm 3) 1/} 2] is preferably 7 to 14, more preferably 8 to 13, particularly preferably Is from 9 to 13. If it is 7 or more, the developability can be further improved, and if 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. 147-154)"
Those with close SP values are likely to mix with each other (highly dispersible), and those with a distant numerical value are difficult to mix.

  From the viewpoint of alkali developability, the hydrophilic functional group contained in the hydrophilic resin (A) is preferably a carboxyl group, an epoxy group, a sulfonic acid group, or a phosphoric acid group, and more preferably a carboxyl group.

  Specific examples of the hydrophilic resin (A) that can be used in the present invention include a hydrophilic epoxy resin (A1) and a hydrophilic (meth) acrylic resin (A2).

A commercially available product can be obtained and used as the hydrophilic epoxy resin (A1).
The hydrophilic epoxy resin (A1) may be a normal commercially available hydrophilic epoxy resin, and may further contain a (meth) acryloyl group or a carboxyl group in the molecule.
For example, in order to further introduce a (meth) acryloyl group into a molecule, a novolac type epoxy resin having an epoxy group in the molecule may be reacted with acrylic acid or methacrylic acid, while a carboxyl group is introduced. For this, an epoxy resin may be reacted with a polyvalent carboxylic acid such as phthalic acid or phthalic anhydride or a polyvalent carboxylic anhydride. Hydrophilic epoxy resins containing both (meth) acryloyl and carboxyl groups are reacted with (meth) acrylic acid first on a novolak-type epoxy resin, and then added with a polyvalent carboxylic acid or polyvalent carboxylic acid anhydride. The method of making it.

  The hydrophilic (meth) acrylic resin (A2) can be obtained by polymerizing a monomer containing a (meth) acrylic acid derivative by an existing method.

  As a method for producing the hydrophilic (meth) acrylic resin (A2), radical polymerization is preferable, and a solution polymerization method is preferable because the molecular weight can be easily adjusted.

  Examples of the monomer constituting the hydrophilic (meth) acrylic resin (A2) include (meth) acrylic acid (a21) and (meth) acrylic acid ester (a22).

  As (a22), carbon number of alkyl group or hydroxyalkyl group such as methyl (meth) acrylate, butyl (meth) acrylate, (meth) acrylate-2-ethylhexyl, hydroxyethyl (meth) acrylate, etc. is 1 to 30 alkyl (meth) acrylates and hydroxyalkyl (meth) acrylates may be mentioned, and methyl (meth) acrylate and hydroxyethyl (meth) acrylate are preferred.

  As a monomer constituting the hydrophilic (meth) acrylic resin (A2), an aromatic ring-containing vinyl compound (a23) having 8 to 30 carbon atoms from the viewpoint of the elastic recovery property of the cured product of the photosensitive resin composition, You may use together with (a21) and (a22). Examples of such (a23) include styrene.

  In the hydrophilic (meth) acrylic resin (A2), it is preferable to introduce a (meth) acryloyl group into a side chain or a terminal as necessary for the purpose of further improving the elastic recovery property of the cured product.

  Examples of the method for introducing a (meth) acryloyl group into the side chain include the following methods (1) and (2).

(1) A polymer is produced using a monomer having a group capable of reacting with an isocyanate group (such as a hydroxyl group or a primary or secondary amino group) in at least a part of (a21) or (a22); A method of reacting a compound having a (meth) acryloyl group and an isocyanate group (such as (meth) acryloyloxyethyl isocyanate).

(2) A polymer is produced using a monomer having a group capable of reacting with an epoxy group (such as a hydroxyl group, a carboxyl group, or a primary or secondary amino group) in at least a part of (a21) or (a22). And then reacting a compound having a (meth) acryloyl group and an epoxy group (such as glycidyl (meth) acrylate).

  Among these, a hydrophilic epoxy resin (A1) is preferable, and a novolak-type epoxy resin that may contain a (meth) acryloyl group and / or a carboxyl group in the molecule is particularly preferable. Since it is excellent in developability, it is a novolak type epoxy resin containing (meth) acryloyl group and / or carboxyl group in the molecule.

The number average molecular weight by the gel permeation chromatography (GPC) method of the hydrophilic resin (A) is preferably 1000 to 30000, more preferably 1500 to 10000.
The number average molecular weight in the present invention uses HLC-8320GPC (manufactured by Tosoh Corp.) as a GPC device, THF solvent, TSK standard polystyrene (manufactured by Tosoh Corp.) as a reference substance, measurement temperature: 40 ° C., Column: measured with Alliance (manufactured by Waters). Moreover, GPC workstation EcoSEC-WS (made by Tosoh Corporation) is used as analysis software.

The content of the hydrophilic resin (A) in the photosensitive resin compositions of the first and second inventions is preferably 5 to 70% by weight, more preferably based on the total weight of (A) to (D). Is 20 to 60% by weight.
If it is 5% by weight or more, formation of a photo spacer is easy because the alkali developability of the photosensitive resin composition is good, and if it is 70% by weight or less, the elastic recovery property of the cured product is better.

The polyfunctional (meth) acrylate (B) that is the second essential component of the photosensitive resin composition of the first and second inventions is not particularly limited as long as it is a known polyfunctional (meth) acrylate. Used.
As such polyfunctional (meth) acrylate (B), bifunctional (meth) acrylate (B1), trifunctional (meth) acrylate (B2), 4-6 functional (meth) acrylate (B3) and 7-10 A functional (meth) acrylate (B4) etc. are mentioned.
For example, bifunctional (meth) acrylate means that the number of (meth) acryloyl groups is two, and the same description method is used hereinafter.

  Examples of the bifunctional (meth) acrylate (B1) include esterified products of a polyhydric (preferably 2 to 8 valent) alcohol having 2 to 30 carbon atoms and (meth) acrylic acid [for example, di (meth) of ethylene glycol. Acrylate, di (meth) acrylate of glycerol, di (meth) acrylate of trimethylolpropane, di (meth) acrylate of 3-hydroxy-1,5-pentanediol, 2-hydroxy-2-ethyl-1,3-propane Di (meth) acrylate of diol]; alkylene oxide (2 to 4 carbon atoms of alkylene group) of a polyhydric (preferably 2 to 8 valent) alcohol having 2 to 30 carbon atoms and (meth) acrylic Acid esterified products [for example, di (meth) acrylates and glycerides of ethylene oxide adducts of trimethylolpropane Di (meth) acrylate of ethylene oxide adduct of ethylene]; epoxy acrylate containing both OH groups; and ester of polyhydric alcohol having 2 to 30 carbon atoms, (meth) acrylic acid and hydroxycarboxylic acid having 3 to 30 carbon atoms [For example, neopentyl glycol di (meth) acrylate hydroxypivalate] and the like.

  The trifunctional (meth) acrylate (B2) may be an ester of an alcohol and (meth) acrylic acid having 3 to 30 carbon atoms (preferably 3 to 8) having 3 to 30 carbon atoms [for example, tri (meth) acrylate of glycerin, tri A tri (meth) acrylate of methylolpropane, a tri (meth) acrylate of pentaerythritol]; and an alkylene oxide of a trivalent or higher (preferably 3-8) valent alcohol having 3 to 30 carbon atoms (the number of carbon atoms of the alkylene group is 2 to 2). 4) 1-30 mol adduct and esterified product of (meth) acrylic acid [for example, tri (meth) acrylate of ethylene oxide adduct of trimethylolpropane] and the like.

  As the tetra- to hexa-functional (meth) acrylate (B3), an esterified product of an alcohol and (meth) acrylic acid having 4 to 30 carbon atoms (preferably 4 to 8) having 5 to 30 carbon atoms [for example, tetra (meth) of pentaerythritol Acrylate, penta (meth) acrylate of dipentaerythritol, and hexa (meth) acrylate of dipentaerythritol]; and alkylene oxides of alkylene having 5 to 30 carbon atoms (preferably 4 to 8 valences) Carbonate 2-4) 1-30 mol adduct and esterified product of (meth) acrylic acid [for example, tetra (meth) acrylate of ethylene oxide adduct of dipentaerythritol, penta (meth) acrylate of ethylene oxide adduct of dipentaerythritol ) Propylene acrylate and dipentaerythritol Penta (meth) acrylate], etc. emissions oxide adducts.

  Examples of the 7 to 10 functional (meth) acrylate (B4) include diisocyanate and the above hydroxyl group-containing polyfunctional (meth) acrylate such as a compound obtained by reaction of dipentaerythritol penta (meth) acrylate and hexamethylene diisocyanate. It can obtain by reaction of.

  Among these, (B2) and (B3) are preferable from the viewpoint of elastic recovery characteristics, and (B3) is more preferable.

The content of the polyfunctional (meth) acrylate (B) in the photosensitive resin composition of the first and second inventions is preferably 20 to 90% by weight based on the total weight of (A) to (D). More preferably, it is 30 to 70% by weight.
When it is 20% by weight or more, the elastic recovery property of the cured product is better, and when it is 90% by weight or less, the developability of the photosensitive resin composition is better and the formation of the photo spacer is easy.

  The aromatic amine (C1), which is the third essential component of the photosensitive resin composition of the first invention, is not particularly limited as long as it is an aromatic ring-containing compound containing an amino group.

For example, a compound represented by the following general formula (1) is preferably used.

[In Formula (1), R < ¹ >, R < ² > is respectively independently a hydrogen atom, a C1-C20 alkyl group, or an aryl group, The same or different group may be sufficient. X is an alkyl group having 1 to 20 carbon atoms, an aryl group, a hydroxyl group, an alkoxy group having 1 to 20 carbon atoms, a phenoxy group, or an amino group. ]

  Specific examples of the aromatic amine (C1) include aniline, 2,4,6-trimethylaniline, anisidine, p-dimethylaminobenzoic acid, p-dimethylaminobenzoic acid ethyl ester, p-dimethylaminobenzoic acid isoamyl ester, and the like. Is mentioned. Of these, p-dimethylaminobenzoic acid ethyl ester is particularly preferably used.

  In addition, as aromatic amine (C1), the compound in which the maximum absorption wavelength exists in 260 nm-360 nm from a sclerosing | hardenable point is preferable, and the compound in which maximum absorption wavelength exists in 280 nm-340 nm is more preferable.

The content of the aromatic amine (C1) in the photosensitive resin composition of the first invention is preferably 1 to 20% by weight, more preferably 2 to 2%, based on the total weight of (A) to (D). 15% by weight.
If it is 1% by weight or more, the resolution of the formed photospacer is good, and if it is 20% by weight or less, the photocurability is improved and the elastic recovery property is better.

  Examples of the photopolymerization initiator (D) that is the fourth essential component of the photosensitive resin compositions of the first and second inventions include known photoradical polymerization initiators. (D) is preferably a compound having a maximum absorption wavelength of 250 to 400 nm, more preferably a compound having a maximum absorption wavelength of 350 to 390 nm, from the viewpoint of curability.

  Examples of the photopolymerization initiator (D) include an acetophenone derivative (D1), an acyl phosphine oxide derivative (D2), a titanocene derivative (D3), and combinations thereof.

  Examples of the acetophenone derivative (D1) include 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, benzyldimethyl ketal, 2-hydroxy-2-methylpropiophenone, 4-isopropyl-2-hydroxy-2-methylpropiophenone, 2 -Methyl-1- (4- (methylthio) phenyl) -2-morpholino-1-propanone, dimethylbenzyl ketal, methylbenzoylformate, 2-benzyl-2-dimethylamino-1- (4-morpholino Eniru) - butan-1-one] and the like.

  Examples of the acylphosphine oxide derivative (D2) include 2,4,6, -trimethylbenzoyl-diphenyl-phosphine oxide and bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide.

  Examples of the titanocene derivative (D3) include bis (η5-2,4-cyclopentadien-1-yl) -bis (2,6-difluoro-3- (1H-pyrrol-1-yl) -phenyl) titanium. .

  Of these (D1) to (D3), 2-methyl-1- (4- (methylthio) phenyl) -2-morpholino-1-propanone, 2-benzyl-2-dimethylamino-1- (4-morpholino) Phenyl) -butan-1-one and bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide are often used, and 2-methyl-1- (4- (methylthio) phenyl)-from the viewpoint of reactivity 2-morpholino-1-propanone and bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide are preferred.

As the radical photopolymerization initiator (D), a commercially available product can be easily obtained. For example, Irgacure 907 is used as 2-methyl-1- (4- (methylthio) phenyl) -2-morpholino-1-propanone. Examples of bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide include Irgacure 819 (manufactured by BASF).
Among these, the acyl phosphine oxide derivative (D2) is preferable from the viewpoint of curability.

The content of the photopolymerization initiator (D) in the photosensitive resin compositions of the first and second inventions is preferably 1 to 20% by weight based on the total weight of (A) to (D), and further Preferably it is 2 to 15% by weight.
If it is 1% by weight or more, it is preferable because photocurability is improved, and if it is 20% by weight or less, the resolution and the elastic recovery characteristic when it is used as a photospacer are better.

The content of the photo-radically polymerizable carbon-carbon double bond (C = C) based on the total weight of (A) to (D) in the photosensitive resin composition according to the first and second inventions is preferably Is used in a range of 3.0 to 8.0 mmol / g, more preferably 3.5 to 7.6 mmol / g, and particularly preferably 4.0 to 7.0 mmol / g.
If it is 3.0 mmol / g or more, the photocurability is sufficient, so that the elastic recovery characteristic is better, and if it is 8.0 mmol / g or less, the adhesion of the cured product to a glass substrate or the like is better.

The second invention contains a hydrophilic resin (A), a polyfunctional (meth) acrylate (B), a compound (C2) that generates an α-aminoalkyl radical, and a photopolymerization initiator (D) as essential components. It is the photosensitive resin composition characterized by the above-mentioned.
In the second invention, the configuration is changed to the compound (C2) in which the aromatic amine (C1) of the first invention generates an α-aminoalkyl radical. Accordingly, the hydrophilic resin (A), the polyfunctional (meth) acrylate (B), and the photopolymerization initiator (D) are common.
In the first invention and the second invention, the first invention using the aromatic amine (C1) is preferred.

  Examples of the compound (C2) that generates this α-aminoalkyl radical include isopropylamine, N-methyl-2-propylamine, N, N-dimethylisopropylamine and the like.

The content of the compound (C2) that generates an α-aminoalkyl radical is preferably 1 to 20% by weight, more preferably 1 to 15% by weight, based on the total weight of (A) to (D). is there.
The aromatic amine (C1) and the compound (C2) that generates an α-aminoalkyl radical may be used together, and the total content of (C1) and (C2) is (A) to (D). Is preferably 1 to 20% by weight, and more preferably 2 to 15% by weight, based on the total weight.
The reason why the above range is preferable is the same as in the case of (C1).

In the photosensitive resin compositions of the first and second inventions, a siloxane compound represented by the following general formula (2) containing at least one alkoxy group for the purpose of further improving the elastic recovery property of the cured product It is preferable to further contain (E).
In the case of a siloxane compound that does not contain an alkoxy group, the elastic recovery characteristics of the cured product cannot be sufficiently improved.

[In Formula (2), R < ³ > and R < ⁴ > are respectively independently an alkyl group, a (meth) acryloyl group, or a (meth) acryloyloxyalkyl group, and carbon number of each functional group is 1-20. R ⁵ and R ⁶ are each independently an alkyl group, alkoxy group, aryl group, mercaptoalkyl group, aminoalkyl group, (meth) acryloyl group, (meth) acryloyloxyalkyl group, (meth) acryloyloxyalkoxy group or It is a (meth) acryloyloxy group, and each functional group has 1 to 20 carbon atoms. When a plurality of R ⁵ and R ⁶ are contained in one molecule depending on the repeating unit, they may be the same or different groups. However, at least one of n R ⁵ and n R ⁶ is an alkoxy group. n is an integer of 1-20. ]

In formula (2), R ³ and R ⁴ are each independently an alkyl group, a (meth) acryloyl group or a (meth) acryloyloxyalkyl group. Examples of the alkyl group used for R ³ and R ⁴ include a linear alkyl group and a branched alkyl group.
Examples of the linear alkyl group include a methyl group, an ethyl group, a butyl group, and an octyl group. Examples of the branched alkyl group include an isopropyl group, an isobutyl group, and a 2-ethylhexyl group.

Examples of the (meth) acryloyl group used for R ³ and R ⁴ include an acryloyl group and a methacryloyl group.

Examples of the (meth) acryloyloxyalkyl group used for R ³ and R ⁴ include a 1-acryloyloxypropyl group and a 1-methacryloyloxypropyl group.

In the formula (2), R ⁵ and R ⁶ are each independently an alkyl group, alkoxy group, aryl group, mercaptoalkyl group, aminoalkyl group, (meth) acryloyl group, (meth) acryloyloxyalkyl group, (meth) When it is an acryloyloxyalkoxy group or a (meth) acryloyloxy group and a plurality of R ⁵ and R ⁶ are contained in one molecule by a repeating unit, they may be the same or different groups. However, at least one of n R ⁵ and n R ⁶ is an alkoxy group.
The alkyl group, (meth) acryloyl group and (meth) acryloyloxyalkyl group used for R ⁵ and R ⁶ are the same as those described for R ³ and R ⁴ above.

Examples of the alkoxy group used for R ⁵ and R ⁶ include a methoxy group, an ethoxy group, a butoxy group, and an octoxy group. Of these, a methoxy group is preferably used from the viewpoint of curability.

Examples of the aryl group used for R ⁵ and R ⁶ include a phenyl group, a biphenyl group, and a naphthyl group.

Examples of the mercaptoalkyl group used for R ⁵ and R ⁶ include a mercaptomethyl group, a mercaptoethyl group, and a mercaptopropyl group.

Examples of the aminoalkyl group used for R ⁵ and R ⁶ include an aminomethyl group, an aminoethyl group, and an aminobutyl group.

Examples of the (meth) acryloyloxy group used for R ⁵ and R ⁶ include an acryloyloxy group and a methacryloyloxy group.

Examples of the (meth) acryloyloxyalkoxy group used for R ⁵ and R ⁶ include a 1-acryloyloxypropoxy group and a 1-methacryloyloxypropoxy group.

  The repeating unit n of the siloxane compound (E) is 1 to 20 and preferably 1 to 15 from the viewpoints of the reactivity and storage stability of the compound.

From the viewpoint of curability of the photosensitive resin composition, the siloxane compound (E) preferably contains a (meth) acryloyloxy group or a (meth) acryloyloxyalkoxy group.
In particular, at least one of R ³ and R ^{4 in} the formula (2) is preferably a (meth) acryloyl group or a (meth) acryloyloxyalkyl group, and at least one of R ⁵ and R ⁶ is A (meth) acryloyl group, a (meth) acryloyloxyalkyl group, a (meth) acryloyloxyalkoxy group or a (meth) acryloyloxy group is preferred.

  The siloxane compound (E) used in the present invention can be obtained by subjecting a silane compound to a condensation reaction in the presence of a catalyst such as an organic acid and water.

  The content of the siloxane compound (E) in the photosensitive resin compositions of the first and second inventions is the sum of (A) to (D) from the viewpoint of the photo-spacer formability and the elastic recovery characteristics of the cured product. Preferably it is 25 weight% or less with respect to a weight, More preferably, it is 1-22 weight%, Most preferably, it is 5-20 weight%.

  The photosensitive resin compositions of the first and second inventions may further contain other components as necessary. Other components include inorganic fine particles, photosensitizers, polymerization inhibitors, solvents, thickeners, surface conditioners, and other additives (eg, silane coupling agents, fluorescent brighteners, yellowing inhibitors) , Antioxidants, antifoaming agents and deodorizing agents).

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”. Examples 1, 3 and 6 are reference examples.

Production Example 1 [Production of hydrophilic resin (A)]
In a glass flask equipped with a heating / cooling / stirring device, a reflux condenser, a dropping funnel and a nitrogen introduction pipe, 200 parts of cresol novolac type epoxy resin “EOCN-102S” (epoxy equivalent 200 manufactured by Nippon Kayaku Co., Ltd.) and propylene 245 parts of glycol monomethyl ether acetate were charged and heated to 90 ° C. to dissolve uniformly. Subsequently, 76 parts of acrylic acid (1.07 mol part), 2 parts of triphenylphosphine and 0.2 part of p-methoxyphenol were charged and reacted at 90 ° C. for 10 hours.
The reaction product was further charged with 91 parts (0.60 mole part) of tetrahydrophthalic anhydride, reacted at 90 ° C. for 5 hours, and then the hydrophilic resin content was adjusted to 50% by weight with propylene glycol monomethyl ether acetate. Dilution was performed to obtain a 50% solution (A-1) of an acryloyl group- and carboxyl group-containing cresol novolac type epoxy resin as the hydrophilic resin (A).
The acid value in terms of solid content of this resin was 88.4. The number average molecular weight (Mn) by GPC was 2,200. The SP value was 11.3 and the HLB value was 9.8.

Production Example 2 [Production of siloxane compound (E) containing at least one alkoxy group and represented by the general formula (2)]
In a glass flask equipped with a heating / cooling / stirring device, a reflux condenser, a dropping funnel and a nitrogen introducing tube, 46 parts (0.2 mole part) of 3-acryloyloxypropyltrimethoxysilane, 160 parts of diphenyldimethoxysilane (0 .65 mol parts), 45 g (2.5 mol parts) of ion-exchanged water, and 0.1 part (0.001 mol parts) of oxalic acid, and heated and stirred at 60 ° C. for 6 hours. The methanol by-produced by hydrolysis was removed over 2 hours under reduced pressure to obtain an acrylic-modified siloxane compound (E-1) (Mn: 2,100).

Examples 1-7 and Comparative Examples 1-3
The hydrophilic resin solution (A-1) produced in Production Example 1 was charged into a glass container according to the number of blended parts in Table 1, and the following (B-1), (B-2), (B'-1) ), (C-1), (C-2), (D-1), and (D-2), and the siloxane compound (E-1) produced in Production Example 2, and stirring until uniform. Furthermore, an additional solvent (propylene glycol monomethyl ether acetate) was added to obtain the photosensitive resin compositions of Examples 1 to 7 and the photosensitive resin compositions of Comparative Examples 1 to 3.

The details of the chemicals in Table 1 are as follows.
(B-1): Dipentaerythritol pentaacrylate (“Neomer DA-600”: manufactured by Sanyo Chemical Industries, Ltd.)
(B-2): Pentaerythritol triacrylate ("Light acrylate PE-3A": manufactured by Kyoeisha Chemical Co., Ltd.)
(B′-1): Phenoxyethyl acrylate (“Light acrylate PO-A”: manufactured by Kyoeisha Chemical Co., Ltd.)
(C-1): p-dimethylaminobenzoic acid ethyl ester (“Kayacure EPA”: Nippon Kayaku Co., Ltd., maximum absorption wavelength: 310 nm)
(C-2): Isopropylamine (D-1): “Irgacure 819” (bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide: manufactured by BASF, maximum absorption wavelength: 370 nm)
(D-2): “Lucirin TPO” (2,4,6-trimethylbenzoyl-diphenylphosphine oxide: manufactured by BASF, maximum absorption wavelength: 380 nm)

The performance evaluation method will be described below.
[Production of photo spacer]
The photosensitive resin composition was applied on a 10 cm × 10 cm square glass substrate by a spin coater and dried to form a coating film having a dry film thickness of 5 μm. This coating film was heated on a hot plate at 80 ° C. for 3 minutes. The obtained coating film was irradiated with 60 mJ / cm ^{2 of} light from an ultrahigh pressure mercury lamp through a plurality of masks for forming a photospacer having 10,000 openings per cm ² and diameters of 7, 8, 9 and 10 μm. (Illuminance 22 mW / cm ^{2 in} terms of i-line).
In addition, the exposure (exposure gap) between the mask and the substrate was 100 μm.
Thereafter, alkali development was performed using a 0.05% aqueous KOH solution. After washing with water, post-baking was performed at 230 ° C. for 30 minutes to form 10,000 photospacers per 1 cm ² on the glass substrate.
Note that a photo spacer having a desired lower base diameter can be formed by adjusting the mask opening diameter.

[Evaluation of adhesion]
With the miniaturization and high definition of the LCD, the size of the photo spacer manufactured on the substrate is required to be 10 μm or less. However, the smaller the ground contact area between the substrate and the photo spacer, the higher the adhesion is required.
In other words, a photo spacer with higher adhesion is more excellent in performance that is less likely to be peeled off by rubbing or the like even if the lower bottom diameter of the spacer is smaller.
Therefore, the adhesiveness was evaluated by setting the bottom bottom diameter of the spacer to 8 μm in diameter and performing the following swab rubbing test.

Select only a mask having a bottom base diameter of 8 μm from the photo spacers prepared using a plurality of masks for forming photo spacers having openings with diameters of 7, 8, 9 and 10 μm, and have the following adhesion properties: A test was conducted.
(1) A cross mark of 1 cm in length and 1 cm in width is marked with an oil-based pen on the back side of the glass substrate on which the photospacer is formed.
(2) First, rubbing the surface of the front side of the glass substrate marked with a cross with a cotton swab soaked with acetone 10 times from the top of the vertical line downward at a speed of 2 cm per second.
Next, rubbing 10 times from the left of the horizontal line to the right at a speed of 2 cm per second.
(3) The number of photo spacers remaining without peeling off the portion where the rubbed portions in (2) intersect with each other is counted with an optical microscope.
In the case where no peeling occurs, there are 100 (10 × 10) spacers per mm ² on the glass substrate.

Judgment criteria are as follows.
◎: The number of spacers peeled off is 5 or less out of 100 ○: The number of spacers peeled off is 6 to 9 out of 100 ×: The number of spacers peeled off is 10 or more out of 100

[Evaluation of elastic recovery characteristics]
The elastic recovery characteristic of the photospacer can be evaluated by the “elastic recovery rate” when a certain pressure defined by the following formula (1) is applied. The higher the elastic recovery rate (%), the better the elastic recovery characteristics.
The elastic recovery characteristic was evaluated by measuring the elastic recovery rate under a pressure condition of 0.5 mN / μm ² .

(1) A micro hardness tester (Fischer Instruments, Inc .; “Fischer Scope H-100”) and a planar indenter having a square cross section for one photo spacer selected arbitrarily from among photo spacers formed on a glass substrate. (50 μm × 50 μm) was used to measure the amount of deformation when a load was applied and when the load was returned.
At this time, a load was applied to 0.5 mN / μm ² over 30 seconds at a load speed of 0.017 mN / μm ² · sec and held for 5 seconds.
The amount of deformation from the initial position of the photospacer in a state where a load was applied was measured. The amount of change at this time is defined as a total deformation amount T ₀ (μm).
(2) Next, the load was released to 0 over 30 seconds at an unloading speed of 0.017 mN / μm ² · sec, and the state was maintained for 5 seconds. The deformation amount of the photo spacer at this time is defined as a plastic deformation amount T ₁ (μm).
(3) From the T ₀ and T ₁ measured as described above, the elastic recovery rate was calculated using the following formula (1).

Elastic recovery rate (%) = [(T ₀ −T ₁ ) / T ₀ ] × 100 (1)

From the value of the elastic recovery rate, the elastic recovery characteristics were determined as follows according to the following criteria.
◎: 75% or more ○: 70% or more and less than 75% ×: less than 70%

[Resolution evaluation]
As LCDs have become smaller and higher definition, and the pixel size has become smaller, fine photo spacers can be formed. That is, patterning with a resolution of 10 μm or less is required as the resolution. It has become.
That is, the higher the resolution, the better the performance of forming a photo spacer having the same size as the mask opening diameter even if the mask opening diameter is reduced.
Therefore, the resolution was evaluated by measuring the lower base diameter of the photo spacer when the photo spacer was formed by the above method with the opening diameter of the mask set to 10 μm.

In the production of the photospacer, a photospacer was formed on a glass substrate by the same method as described above except that a photomask having a pattern having an opening diameter of 10 μm was used instead of 9 μm in diameter.
The lower base diameter of the photo spacer was measured with a laser microscope, and this was used as an evaluation of resolution. It can be said that the smaller the bottom diameter, the higher the resolution.

Criteria based on the lower base diameter of the spacer are as follows.
○: Less than 11 μm ×: 11 μm or more

As shown in Table 1, the photosensitive resin compositions of Examples 1 to 7 of the first or second invention are excellent in all points of adhesion, elastic recovery characteristics, and resolution.
On the other hand, the comparative example 1 which does not contain a polyfunctional (meth) acrylate (B) does not satisfy elastic recovery characteristics and resolution. Further, Comparative Example 2 using a monofunctional acrylate instead of the polyfunctional (meth) acrylate (B) does not satisfy the elastic recovery property. Further, Comparative Example 3 containing neither the aromatic amine (C1) nor the compound (C2) that generates an α-aminoalkyl radical does not satisfy the resolution.

  Since the photosensitive resin composition of the present invention is excellent in elastic recovery characteristics after curing and adhesion to a glass substrate, it is cured as a photospacer, insulating film or protective film on a display element, color filter or panel. It can be suitably used as a photo spacer for display elements, a color filter protective film, a touch panel protective film, or a touch panel insulating film forming resist. Furthermore, it is also suitable as a photosensitive resin composition for various other 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 material.

Claims (7)

Hydrophilic resin (A), polyfunctional (meth) acrylate (B), aromatic amine (C1), siloxane compound (E) represented by the following general formula (2) containing at least one alkoxy group, and light A photosensitive resin composition comprising a polymerization initiator (D) as an essential component.

[In Formula (2), R < ³ > and R < ⁴ > are respectively independently an alkyl group, a (meth) acryloyl group, or a (meth) acryloyloxyalkyl group, and carbon number of each functional group is 1-20. R ⁵ and R ⁶ are each independently an alkyl group, alkoxy group, aryl group, mercaptoalkyl group, aminoalkyl group, (meth) acryloyl group, (meth) acryloyloxyalkyl group, (meth) acryloyloxyalkoxy group or It is a (meth) acryloyloxy group, and each functional group has 1 to 20 carbon atoms. When a plurality of R ⁵ and R ⁶ are contained in one molecule by repeating units, they may be the same or different groups. However, at least one of n R ⁵ and n R ⁶ is an alkoxy group. n is an integer of 1-20. ] The photosensitive resin composition according to claim 1, wherein the aromatic amine (C1) is a compound represented by the following general formula (1).

[In Formula (1), R < ¹ >, R < ² > is respectively independently a hydrogen atom, a C1-C20 alkyl group, or an aryl group, The same or different group may be sufficient. X is an alkyl group having 1 to 20 carbon atoms, an aryl group, a hydroxyl group, an alkoxy group having 1 to 20 carbon atoms, a phenoxy group, or an amino group. ]   The photosensitive resin composition of Claim 1 or 2 in which the maximum absorption wavelength of this aromatic amine (C1) exists in 260 nm-360 nm.   The photosensitive resin composition in any one of Claims 1-3 in which the maximum absorption wavelength of this photoinitiator (D) exists in 250-400 nm.   The photosensitive resin composition according to any one of claims 1 to 4, wherein the photopolymerization initiator (D) is an acylphosphine oxide derivative.   The content of the photo-radically polymerizable carbon-carbon double bond (C = C) based on the total weight of (A), (B), (C), and (D) of the photosensitive resin composition is 3.0. It is -8.0 mmol / g, The photosensitive resin composition in any one of Claims 1-5.   Based on the total weight of (A), (B), (C), and (D) of the photosensitive resin composition, 5 to 70% by weight of the hydrophilic resin (A) and the polyfunctional (meth) acrylate 20 to 90% by weight of (B), 1 to 20% by weight of the total amount of the aromatic amine (C1) and the compound (C2) that generates the α-aminoalkyl radical, and the photopolymerization initiator (D) The photosensitive resin composition in any one of Claims 1-6 containing 1-20 weight%.