JP6236280B2 - Photo spacer - Google Patents

Description

  The present invention relates to a photospacer.

  In a liquid crystal cell of a liquid crystal display device, a liquid crystal layer is formed between a pair of substrates, and a spacer is disposed in order to keep the distance between the substrates constant. In recent years, columnar spacers (photo spacers) formed by photolithography have been used as spacers instead of spacer particles such as glass beads and resin beads (for example, Patent Documents 1 and 2). The photospacer is formed in a substantially columnar shape by applying a photosensitive resin composition on a substrate, exposing it to a predetermined mask, and then developing it. Since the photo spacer can be formed at an arbitrary position, for example, it can be formed only on the black matrix to prevent the display characteristics from deteriorating due to the spacer.

  The characteristics required for the photospacer include high elastic recovery for maintaining the substrate spacing constant, breaking strength, adhesion to the substrate, and the like. These characteristics are required to be satisfied at a higher level as the quality of liquid crystal display devices increases. In addition, with the increase in quality of liquid crystal display devices, photo spacers are required to have a thin and fine shape, and are usually designed with a horizontal sectional diameter of about 10 μm to 20 μm (for example, Patent Document 3). ).

  However, if it is too thin, high elastic recovery, fracture strength, adhesion and the like become insufficient, and it is therefore difficult to further reduce the horizontal cross-sectional diameter of the photo spacer.

JP 2009-53663 A JP 2009-175647 A JP 2006-84629 A

  The present invention has been made in order to solve the above-mentioned problems, and its object is to provide a photospacer having a small horizontal section diameter and excellent in high elastic recovery, fracture strength and substrate adhesion. There is to do.

式（４）〜（７）中、Ｒ^１、Ｒ^２、Ｒ^３、Ｒ^４、Ｒ^５およびＲ^６はそれぞれ独立して、水素原子または炭素数が１〜３０の直鎖状もしくは分岐状のアルキル基である。
好ましい実施形態においては、上記水平断面積Ａ１と上記水平断面積Ａ２との比（Ａ２／Ａ１）が、１〜１．３である。
本発明の別の局面によれば、液晶ディスプレイが提供される。この液晶ディスプレイは、上記フォトスペーサーを含む。 The photospacer of the present invention is a columnar photospacer formed from a photosensitive resin composition containing an alkali-soluble resin and a polyfunctional monomer,
The horizontal cross-sectional area A1 of the portion away from the lower part of the photospacer in the height direction (height of photospacer × 1/2) is equal to the height direction from the lower part of the photospacer (height of photospacer × 1 / 4) The horizontal cross-sectional area A2 or less at the distant portion, and the diameter at the bottom of the photospacer is 8 μm or less.
In a preferred embodiment, the photo spacer of the present invention has a breaking strength of 160 mN to 300 mN.
In preferable embodiment, the said photosensitive resin composition further contains 2 or more types of photoinitiators.
In a preferred embodiment, the polyfunctional monomer has a pentaerythritol skeleton.
In a preferred embodiment, the photosensitive resin composition includes a first photopolymerization initiator having a maximum absorption wavelength at a wavelength of 290 nm to 380 nm, and a second photopolymerization initiator having a maximum absorption wavelength at a wavelength of 230 nm to 290 nm. Including.
In a preferred embodiment, the alkali-soluble resin has a repeating unit having a ring structure in the main chain and a repeating unit having a carbon double bond in the side chain.
In a preferred embodiment, the repeating unit having a ring structure in the main chain is at least one selected from repeating units represented by the general formulas (1) to (7):

In formulas (4) to (7), R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are each independently a hydrogen atom or a linear or branched group having 1 to 30 carbon atoms. It is an alkyl group.
In a preferred embodiment, the ratio (A2 / A1) of the horizontal cross-sectional area A1 and the horizontal cross-sectional area A2 is 1 to 1.3.
According to another aspect of the present invention, a liquid crystal display is provided. This liquid crystal display includes the photo spacer.

  According to the present invention, it is possible to obtain a photospacer having a small diameter in the horizontal cross section without reducing the high elastic recovery property, the breaking strength, and the substrate adhesion by adopting a non-inverted taper shape.

  Further, the non-reverse tapered photo spacer can prevent bubbles from being mixed into the liquid crystal layer and can contribute to the improvement of the display performance of the display device.

(A) And (b) is a schematic sectional drawing of the photospacer by preferable embodiment of this invention. It is a schematic sectional drawing explaining the photo spacer of a reverse taper shape.

A. Photospacer The photospacer of the present invention is a columnar photospacer formed from a photosensitive resin composition. In the present specification, “columnar” is a concept including a columnar shape, an elliptical columnar shape, a prismatic shape, a truncated cone shape, and a truncated pyramid shape. FIG. 1A is a schematic cross-sectional view of a photospacer according to a preferred embodiment of the present invention. The photo spacer 10 has substantially no diameter difference in the height direction and is substantially rectangular. FIG. 1B is a schematic cross-sectional view of a photospacer according to another preferred embodiment of the present invention. The photo spacer 20 has a trapezoid shape that is thinner at the top than at the bottom. As illustrated in FIGS. 1A and 1B, the photospacer of the present invention has a horizontal portion H1 that is separated from the lower part of the photospacer in the height direction (height L × 1/2 of the photospacer). The cross-sectional area A1 is equal to or less than the horizontal cross-sectional area A2 of the portion H2 that is separated from the lower part of the photo spacer in the height direction (height L × 1/4 of the photo spacer). In the present specification, the shape in which the horizontal cross-sectional area A1 and the horizontal cross-sectional area A2 have a relationship of A2 ≧ A1 is referred to as “non-reverse tapered shape”. A shape in which the horizontal cross-sectional area A1 and the horizontal cross-sectional area A2 are in a relationship of A2 <A1 (for example, the shape shown in FIG. 2) is referred to as an “inverse tapered shape”. In the present invention, by adopting such a non-inverted taper shape, even if the diameter is small (specifically, the diameter at the lowermost portion is 8 μm or less, as will be described later), the mechanical properties such as the elastic recovery rate and breaking strength are obtained. A photo spacer having excellent physical properties and substrate adhesion can be obtained.

  The horizontal cross-sectional area A1 of the portion H1 separated from the lower part of the photo spacer in the height direction (height L × 1/2 of the photo spacer) and in the height direction from the lower part of the photo spacer (height L × 1 of the photo spacer / 4) The ratio (A2 / A1) of the distant portion H2 to the horizontal cross-sectional area A2 is preferably 1-1.3, more preferably 1-1.2, and still more preferably 1-1. 15, particularly preferably 1 to 1.1. A photospacer having such a range of A2 / A1 has excellent substrate adhesion, and has a high elastic recovery rate and high fracture strength. Further, the photospacer can prevent bubbles from being mixed into the liquid crystal layer, and can contribute to the improvement of the display performance of the display device.

  The diameter of the lowermost part of the photo spacer (the diameter of the horizontal cross section) is 8 μm or less, preferably 5 μm to 8 μm, more preferably 6 μm to 8 μm, and particularly preferably 6 μm to 7.5 μm. If it is such a range, the photo spacer which can respond to the high definition of a display apparatus can be obtained. In this specification, “diameter” means a length of a straight line that connects two points on the circumference of the lowermost surface and passes through the center of gravity of the lowermost surface. Therefore, when the photo spacer has a cylindrical shape or a truncated cone shape (that is, when the lowermost surface is circular), it means the diameter of the lowermost surface.

Thickness at the bottom of the photo spacers, in terms of the horizontal cross-sectional area of the photo spacers, preferably 3μm ² ~50μm ^2, more preferably 3μm ^{2 ~45μm 2,} further preferably 12μm ² ~45μm ² There, particularly preferably 20μm ² ~45μm ^2.

  The height of the photo spacer can be set to any appropriate height depending on the desired substrate interval. The height of the photo spacer is, for example, 1 μm to 10 μm.

  In one embodiment, the compression ratio of the photospacer of the present invention is 10% to 90%. A method for evaluating the compression rate will be described later.

  The lower limit of the elastic recovery rate of the photospacer of the present invention is preferably 55% or more, more preferably 60% or more, still more preferably 65% or more, still more preferably 70% or more, and further preferably Is 75% or more, more preferably 80% or more, and particularly preferably 90% or more. The larger the elastic recovery rate, the better. The upper limit of the elastic recovery rate of the photospacer of the present invention is, for example, 100%. The method for evaluating the elastic recovery rate will be described later.

  In one embodiment, when the diameter at the bottom of the photo spacer is 6 μm to 8 μm, the elastic recovery rate of the photo spacer of the present invention is preferably 70% to 100%, more preferably 80% to 95%. %.

  The relationship between the elastic recovery rate b (%) of the photospacer of the present invention and the diameter a (μm) at the lowermost part of the photospacer is preferably b> 3.1a + 45 in the range of the practical diameter a. More preferably, b> 3.1a + 50, and more preferably b> 3.1a + 53.

  The lower limit of the breaking strength of the photospacer of the present invention is preferably 20 mN or more, more preferably 50 mN or more, further preferably 100 mN or more, further preferably 130 mN or more, and further preferably 145 mN or more. More preferably, it is 160 mN or more, particularly preferably 175 mN or more, and most preferably 190 mN or more. The higher the breaking strength, the better. The upper limit value of the breaking strength of the photospacer of the present invention is, for example, preferably 300 mN. A method for evaluating the fracture strength will be described later.

  In one embodiment, when the diameter at the bottom of the photospacer is 6 μm to 8 μm, the breaking strength of the photospacer of the present invention is preferably 160 mN to 300 mN, more preferably 160 mN to 250 mN, Preferably, it is 175 mN to 200 mN.

B. Photosensitive resin composition The photosensitive resin composition contains an alkali-soluble resin as a binder polymer and a polyfunctional monomer. Practically, the photosensitive resin composition may further include a photopolymerization initiator, a solvent, and an additive.

B-1. Alkali-soluble resin Any appropriate resin can be used as the alkali-soluble resin as long as the effects of the present invention are obtained. The alkali-soluble resin is preferably an acrylic resin, a polyester resin, or a polyether resin, and more preferably an acrylic resin.

  The acrylic resin preferably has a repeating unit (A) having a ring structure in the main chain. By using an acrylic resin having a repeating unit (A) having a cyclic structure in the main chain, a photosensitive resin composition having high solubility in a developer can be obtained. If such a photosensitive resin composition is used, a photo spacer can be formed without generating a development residue. Further, when an acrylic resin having a repeating unit (A) having a cyclic structure in the main chain is used, a photospacer excellent in substrate adhesion can be obtained even if the diameter is small.

Examples of the repeating unit (A) having a ring structure in the main chain include a repeating unit having a maleimide structure, an N-substituted maleimide structure, a lactone ring structure, a glutaric anhydride structure, a maleic anhydride structure, and the like. Of these, a maleimide structure or an N-substituted maleimide structure is preferable. By using an acrylic resin having a repeating unit having a maleimide structure or an N-substituted maleimide structure in the main chain, a photosensitive resin composition having higher solubility in a developer can be obtained. Specifically, the repeating unit (A) having a ring structure in the main chain is preferably at least one selected from repeating units represented by the general formulas (1) to (3). It is more preferable that it is a repeating unit represented by. If an acrylic resin having a repeating unit represented by the general formula (1) is used, a photospacer with higher breaking strength can be obtained.

式（４）〜（７）中、Ｒ^１、Ｒ^２、Ｒ^３、Ｒ^４、Ｒ^５およびＲ^６はそれぞれ独立して、水素原子または炭素数が１〜３０の直鎖状もしくは分岐状のアルキル基であり、好ましくは水素原子または炭素数が１〜１０の直鎖状もしくは分岐状のアルキル基であり、より好ましくは水素原子または炭素数が１〜５の直鎖状もしくは分岐状のアルキル基であり、さらに好ましくはメチル基である。 The repeating unit (A) having a ring structure in the main chain may be at least one selected from repeating units represented by the general formulas (4) to (7). Among them, the repeating unit represented by the general formula (4) or (7) is preferable.

In formulas (4) to (7), R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are each independently a hydrogen atom or a linear or branched group having 1 to 30 carbon atoms. An alkyl group, preferably a hydrogen atom or a linear or branched alkyl group having 1 to 10 carbon atoms, and more preferably a hydrogen atom or a linear or branched alkyl group having 1 to 5 carbon atoms. Group, more preferably a methyl group.

式（８）および（９）中、Ｒ^１、Ｒ^２およびＲ^３は上記で説明したとおりである。 The acrylic resin having the repeating unit (A) having a ring structure in the main chain can be obtained by polymerizing a monomer composition containing the monomer (a) having a ring structure in the main chain. Examples of the monomer (a) having a ring structure in the main chain include maleimide, benzylmaleimide, phenylmaleimide, naphthylmaleimide, N-o-hydroxyphenylmaleimide, Nm-hydroxyphenylmaleimide, Np-hydroxyphenylmaleimide. N-o-chlorophenylmaleimide, Nm-chlorophenylmaleimide, Np-chlorophenylmaleimide, No-methylphenylmaleimide, Nm-methylphenylmaleimide, Np-methylphenylmaleimide, N-o- Aromatic substituted maleimides such as methoxyphenylmaleimide, Nm-methoxyphenylmaleimide, Np-methoxyphenylmaleimide; cyclohexylmaleimide, methylmaleimide, ethylmaleimide, propylmaleimide, isopropyl Alkyl-substituted maleimides such as Rumareimido like. These monomers may be used alone or in combination of two or more. Among these, maleimide, benzylmaleimide, phenylmaleimide, and cyclohexylmaleimide are preferable, benzylmaleimide, phenylmaleimide, and cyclohexylmaleimide are more preferable, and benzylmaleimide is more preferable. Examples of the monomer (a) constituting the repeating unit represented by the general formulas (4) to (7) include 1,6-dienes represented by the general formula (8) or (9).

In formulas (8) and (9), R ¹ , R ² and R ³ are as described above.

  In the monomer composition, the content of the monomer (a) constituting the repeating unit (A) having a cyclic structure in the main chain is preferably 5% by weight to 50% by weight with respect to the total amount of monomers in the monomer composition. %, More preferably 8 to 30% by weight, and still more preferably 10 to 20% by weight.

  Preferably, the acrylic resin has a repeating unit (B) having an acid group in the side chain. If the acrylic resin has a repeating unit (B) having an acid group in the side chain, a photosensitive resin composition having excellent alkali developability can be obtained. Examples of the monomer (b) constituting the repeating unit (B) having an acid group in the side chain include (meth) acrylic acid, 2- (meth) acryloyloxyethyl succinic acid, itaconic acid, ω-carboxy-poly Monomers having a carboxyl group such as caprolactone monoacrylate; monomers having a carboxylic anhydride group such as maleic anhydride and itaconic anhydride. Of these, (meth) acrylic acid is preferred.

  In the monomer composition, the content of the monomer (b) constituting the repeating unit (B) having an acid group in the side chain is preferably 10% by weight to 90% by weight with respect to the total amount of monomers in the monomer composition. %, More preferably 15% by weight to 85% by weight, and still more preferably 20% by weight to 80% by weight.

  Preferably, the acrylic resin has a repeating unit (C) having a carbon double bond in the side chain. If the acrylic resin has a repeating unit (C) having a carbon double bond in the side chain, a photospacer having high exposure sensitivity and high elastic recovery and breaking strength can be obtained. The repeating unit (C) having a carbon double bond in the side chain is composed of a part of or all (preferably a part) of the acid group of the repeating unit (B) having an acid group in the side chain as a reaction point. It can be obtained by adding a compound having a heavy bond.

  When the acid group of the repeating unit (B) having an acid group in the side chain is a carboxyl group, the compound having a carbon double bond is a compound having an epoxy group and a double bond, an isocyanate group and a double bond. Or the like. Examples of the compound having an epoxy group and a double bond include glycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, o-vinylbenzyl glycidyl ether, m-vinylbenzyl glycidyl ether, and p-vinyl. Examples include benzyl glycidyl ether and 4-hydroxybutyl acrylate glycidyl ether. Examples of the compound having an isocyanate group and a double bond include 2-isocyanatoethyl (meth) acrylate. When the acid group of the repeating unit (B) having an acid group in the side chain is a carboxylic anhydride group, a compound having a hydroxyl group and a double bond can be used as the compound having a carbon double bond. Examples of the compound having a hydroxyl group and a double bond include 2-hydroxyethyl (meth) acrylate.

式（１０）中、Ｒ^７、Ｒ^８およびＲ^９はそれぞれ独立して、水素原子またはメチル基であり、好ましくは水素原子である。Ｒ^１０は、炭素数が１〜２０の直鎖状もしくは分岐状のアルキル基、炭素数が２〜２０の直鎖状もしくは分岐状のアルケニル基または炭素数が６〜２０の芳香族炭化水素基であり、好ましくは水素原子、炭素数が１〜２０の直鎖状のアルキル基、炭素数が２〜２０の直鎖状のアルケニル基または炭素数が６〜２０の芳香族炭化水素基であり、より好ましくは炭素数が１〜１０の直鎖状のアルキル基または炭素数が６〜１２の芳香族炭化水素基であり、さらに好ましくは炭素数が１〜５の直鎖状のアルキル基、フェニル基またはビフェニル基であり、特に好ましくはメチル基、フェニル基またはビフェニル基である。なお、アルキル基、アルケニル基および芳香族炭化水素基は、置換基を有していてもよい。ＡＯは、オキシアルキレン基を表す。ＡＯで表されるオキシアルキレン基の炭素数は２〜２０であり、好ましくは２〜１０であり、より好ましくは２〜５であり、さらに好ましくは２である。繰り返し単位（Ｄ）は１種または２種以上のオキシアルキレン基を含み得る。ｘは０〜２の整数を表す。ｙは０または１を表す。ｎは、オキシアルキレン基の平均付加モル数を表し、２以上であり、好ましくは２〜１００であり、より好ましくは２〜５０であり、さらに好ましくは２〜１５である。 The acrylic resin preferably further has a repeating unit (D) having two or more oxyalkylene groups in the side chain. When the acrylic resin has a repeating unit (D) having two or more oxyalkylene groups in the side chain, a photospacer having a high crosslinking density, a high elastic recovery rate and a high breaking strength can be obtained. Examples of the repeating unit (D) having two or more oxyalkylene groups in the side chain include a repeating unit represented by the general formula (10).

In formula (10), R ⁷ , R ⁸ and R ⁹ are each independently a hydrogen atom or a methyl group, preferably a hydrogen atom. R ¹⁰ is a linear or branched alkyl group having 1 to 20 carbon atoms, a linear or branched alkenyl group having 2 to 20 carbon atoms, or an aromatic hydrocarbon group having 6 to 20 carbon atoms. And preferably a hydrogen atom, a linear alkyl group having 1 to 20 carbon atoms, a linear alkenyl group having 2 to 20 carbon atoms, or an aromatic hydrocarbon group having 6 to 20 carbon atoms. More preferably a linear alkyl group having 1 to 10 carbon atoms or an aromatic hydrocarbon group having 6 to 12 carbon atoms, and still more preferably a linear alkyl group having 1 to 5 carbon atoms, A phenyl group or a biphenyl group, particularly preferably a methyl group, a phenyl group or a biphenyl group. In addition, the alkyl group, the alkenyl group, and the aromatic hydrocarbon group may have a substituent. AO represents an oxyalkylene group. The oxyalkylene group represented by AO has 2 to 20 carbon atoms, preferably 2 to 10 carbon atoms, more preferably 2 to 5 carbon atoms, and even more preferably 2. The repeating unit (D) may contain one or more oxyalkylene groups. x represents an integer of 0-2. y represents 0 or 1; n represents the average addition mole number of an oxyalkylene group and is 2 or more, preferably 2 to 100, more preferably 2 to 50, and further preferably 2 to 15.

式（１１）中、Ｒ^７、Ｒ^８、Ｒ^９、Ｒ^１０、ＡＯ、ｘ、ｙおよびｎは、上記で説明したとおりである。 The repeating unit (D) having two or more oxyalkylene groups in the side chain is composed of a monomer (d) having two or more oxyalkylene groups in the side chain. As a monomer (d), the monomer represented by General formula (11) is mentioned, for example.

In formula (11), R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , AO, x, y and n are as described above.

  Examples of the monomer (d) include ethoxylated o-phenylphenol (meth) acrylate (EO 2 mol), phenoxydiethylene glycol (meth) acrylate, phenoxypolyethylene glycol (meth) acrylate (EO 4 mol), and methoxypolyethylene glycol (meth) acrylate. (EO 9 mol), methoxypolyethylene glycol (meth) acrylate (EO 13 mol), methoxytriethylene glycol (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, butoxydiethylene glycol (meth) acrylate, 2-ethylhexyldiethylene glycol (meth) acrylate, methoxy Dipropylene glycol (meth) acrylate, methoxypolypropylene glycol (meth) acrylate DOO, nonyl phenoxy polyethylene glycol (meth) acrylate (EO4-17 moles), nonylphenoxy polypropylene glycol (meth) acrylate (PO5 mol), EO-modified cresol (meth) acrylate (EO2 mol), and the like. These monomers may be used alone or in combination of two or more. Among them, ethoxylated o-phenylphenol (meth) acrylate (EO 2 mol), methoxypolyethylene glycol (meth) acrylate (EO 9 mol), and methoxypolyethylene glycol (meth) acrylate (EO 13 mol) are preferable. More preferred are ethoxylated o-phenylphenol acrylate (EO 2 mol), methoxy polyethylene glycol acrylate (EO 9 mol), and methoxy polyethylene glycol acrylate (EO 13 mol). If these monomers (d) are used, a photo spacer having an excellent elastic recovery rate can be easily obtained. In the present specification, for example, “EO2 mole”, “PO5 mole” and the like represent the average number of moles added of the oxyalkylene group.

  In the monomer composition, the content ratio of the monomer (d) constituting the repeating unit (D) having two or more oxyalkylene groups in the side chain is preferably 0. 0 relative to the total amount of monomers in the monomer composition. It is 5 to 55% by weight, more preferably 1 to 50% by weight, and further preferably 1 to 45% by weight.

  The acrylic resin may further have another repeating unit (E) derived from another monomer (e) copolymerizable with the monomer (a), the monomer (b) and / or the monomer (c). The other monomer (e) preferably has no epoxy group. By using another monomer (e) having no epoxy group, that is, by using an acrylic resin having no epoxy group as an alkali-soluble resin, a photosensitive resin composition having excellent storage stability is obtained. Can do.

  Examples of the other monomer (e) include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, and isobutyl (meth) acrylate. , T-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, phenyl (meth) acrylate, biphenyl (meth) acrylate, methoxyethyl ( (Meth) acrylate, ethoxyethyl (meth) acrylate, butoxyethylene glycol (meth) acrylate, 2-ethylhexyl ethylene glycol (meth) acrylate, methoxypropylene glycol (Meth) acrylate, phenoxyethyl (meth) acrylate, biphenoxyethyl (meth) acrylate, dicyclopentanyl (meth) acrylate, tricyclodecyl (meth) acrylate, dicyclopentanyloxyethyl (meth) acrylate, tricyclo Such as decyloxyethyl (meth) acrylate, nonylphenoxyethylene glycol (meth) acrylate, nonylphenoxypropylene glycol, benzyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, ethoxylated o-phenylphenol (meth) acrylate ( (Meth) acrylic acid esters, (meth) acryloylmorpholine (morpholino (meth) acrylate), (meth) acrylamide, N-methyl (meth) acrylamide, N-iso Lopyl (meth) acrylamide, N-butyl (meth) acrylamide, N-isobutyl (meth) acrylamide, Nt-butyl (meth) acrylamide, Nt-octyl (meth) acrylamide, diacetone (meth) acrylamide, N -Hydroxymethyl (meth) acrylamide, N-hydroxyethyl (meth) acrylamide, N-cyclohexyl (meth) acrylamide, N-phenyl (meth) acrylamide, N-benzyl (meth) acrylamide, N-triphenylmethyl (meth) acrylamide , (Meth) acrylic acid amides such as N, N-dimethyl (meth) acrylamide, aromatic vinyl compounds such as styrene, vinyltoluene and α-methylstyrene, butadiene or substituted butadiene compounds such as butadiene and isoprene, Styrene, propylene, vinyl chloride, ethylene or substituted ethylene compound such as acrylonitrile, vinyl esters such as vinyl acetate and the like. These monomers may be used alone or in combination of two or more.

  The content ratio of the monomer (e) constituting the other repeating unit (E) in the monomer composition is preferably 0% by weight to 55% by weight with respect to the total amount of monomers in the monomer composition, and more Preferably they are 5 weight%-50 weight%, More preferably, they are 10 weight%-45 weight%.

  The acrylic resin may be a random copolymer or a block copolymer.

  The weight average molecular weight of the acrylic resin is preferably a value measured by gel permeation chromatography (GPC) with a tetrahydrofuran (THF) solvent, preferably 3,000 to 200,000, more preferably It is 4,000-100,000, More preferably, it is 5,000-50,000. If it is such a range, the photosensitive resin composition which can ensure heat resistance and has a viscosity suitable for coating film formation can be obtained.

  The acid value of the acrylic resin is preferably 20 mgKOH / g to 300 mgKOH / g, more preferably 25 mgKOH / g to 200 mgKOH / g, and further preferably 30 mgKOH / g to 150 mgKOH / g. If it is such a range, the photo spacer which is excellent in alkali developability, there is little generation | occurrence | production of a development residue, and is excellent in adhesiveness can be obtained.

  The acrylic resin can be obtained by polymerizing the monomer composition by any appropriate method. Examples of the polymerization method include a solution polymerization method.

  The monomer composition can include any suitable solvent. Examples of the solvent include ethers such as tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, and propylene glycol monomethyl ether; ketones such as acetone and methyl ethyl ketone; ethyl acetate, butyl acetate, propylene glycol monomethyl ether acetate, and 3-methoxybutyl. Examples include esters such as acetate; alcohols such as methanol and ethanol; aromatic hydrocarbons such as toluene, xylene and ethylbenzene; chloroform; dimethyl sulfoxide and the like. These solvents may be used alone or in combination of two or more. The polymerization concentration when polymerizing the monomer composition is preferably 5% by weight to 90% by weight, more preferably 5% by weight to 50% by weight, and further preferably 10% by weight to 50% by weight. .

  The monomer composition can include any suitable polymerization initiator. Examples of the polymerization initiator include cumene hydroperoxide, diisopropylbenzene hydroperoxide, di-t-butyl peroxide, lauroyl peroxide, benzoyl peroxide, t-butyl peroxyisopropyl carbonate, and t-amyl peroxy-2. Organic peroxides such as ethylhexanoate and t-butylperoxy-2-ethylhexanoate; 2,2′-azobis (isobutyronitrile), 1,1′-azobis (cyclohexanecarbonitrile), Examples thereof include azo compounds such as 2,2′-azobis (2,4-dimethylvaleronitrile) and dimethyl 2,2′-azobis (2-methylpropionate). The content ratio of the polymerization initiator is preferably 0.1 parts by weight to 15 parts by weight, more preferably 0.5 parts by weight to 10 parts by weight with respect to 100 parts by weight of the total monomer in the monomer composition.

  The polymerization temperature when the acrylic resin is polymerized by the solution polymerization method is preferably 40 ° C to 150 ° C, more preferably 60 ° C to 130 ° C.

  When obtaining the acrylic resin which has a repeating unit (C) which has a carbon double bond in a side chain, the compound which has the said carbon double bond is added to the obtained acrylic resin after the said superposition | polymerization. Any appropriate method can be adopted as a method for adding a compound having a carbon double bond. For example, in the presence of a polymerization inhibitor and a catalyst, a compound having a carbon double bond is reacted with part or all (preferably part) of the acid group of the repeating unit (B) having an acid group in the side chain. Thus, the repeating unit (C) having a carbon double bond in the side chain can be formed.

  The addition amount of the compound having a carbon double bond is preferably 5% with respect to 100 parts by weight of the acrylic resin after the polymerization (that is, the acrylic resin before adding the compound having a carbon double bond). Part or more, more preferably 10 parts by weight or more, still more preferably 15 parts by weight or more, and particularly preferably 20 parts by weight or more. If it is such a range, the photosensitive resin composition excellent in exposure sensitivity can be obtained. If such a photosensitive resin composition is used, a dense cured coating film can be formed, and a photospacer having excellent substrate adhesion, high elastic recovery rate and high breaking strength can be formed. In addition, if the addition amount of the compound having a carbon double bond is within the above range, a photosensitive resin composition in which hydroxyl groups are sufficiently generated by the addition of the compound having a carbon double bond and the solubility in an alkali developer is excellent. Can be obtained. The upper limit of the amount of the compound having a carbon double bond is preferably 100 parts by weight with respect to 100 parts by weight of the acrylic resin after polymerization (that is, the acrylic resin before adding the compound having a carbon double bond). It is 170 parts by weight or less, more preferably 150 parts by weight or less, and still more preferably 140 parts by weight or less. When there is too much addition amount of the compound which has a carbon double bond, there exists a possibility that the storage stability and solubility of a photosensitive resin composition may fall.

  Examples of the polymerization inhibitor include alkylphenol compounds such as 6-tert-butyl-2,4-xylenol. Examples of the catalyst include tertiary amines such as dimethylbenzylamine and triethylamine.

B-2. Multifunctional monomer The photosensitive resin composition may further contain a polyfunctional monomer. Examples of the polyfunctional monomer include polyfunctional aromatic vinyl monomers such as divinylbenzene, diallyl phthalate, and diallylbenzene phosphonate; (di) ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, trimethylolpropane di (Meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol di (meth) acrylate, dipentaerythritol Tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol Hexa (meth) acrylate, tripentaerythritol di (meth) acrylate, tripentaerythritol tri (meth) acrylate, tripentaerythritol tetra (meth) acrylate, tripentaerythritol penta (meth) acrylate, tripentaerythritol hexa (meth) acrylate , Tripentaerythritol hepta (meth) acrylate, tripentaerythritol octa (meth) acrylate, trifunctional (meth) acrylates such as tris (hydroxyethyl) isocyanurate tri (meth) acrylate; these monomers are modified with caprolactone or alkylene Examples thereof include oxide-modified polyfunctional monomers. When these polyfunctional monomers are used, a photo spacer having a high crosslinking density can be obtained because of the large number of functional groups.

  The polyfunctional monomer preferably has a pentaerythritol skeleton. Examples of the polyfunctional monomer having a pentaerythritol skeleton include pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol di (meth) acrylate, and dipentaerythritol tris. (Meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, tripentaerythritol di (meth) acrylate, tripentaerythritol tri (meth) acrylate, Tripentaerythritol tetra (meth) acrylate, tripentaerythritol penta (meth) acrylate, tripentaerythritol Ruhekisa (meth) acrylate, tripentaerythritol hepta (meth) acrylate, tripentaerythritol octa (meth) acrylate. If a polyfunctional monomer having a pentaerythritol skeleton is used, a photo spacer having a high elastic recovery rate can be obtained even if the diameter is small.

  The content ratio of the polyfunctional monomer is preferably 10 parts by weight to 90 parts by weight, more preferably 30 parts by weight to 85 parts by weight with respect to 100 parts by weight of the total weight of the alkali-soluble resin and the polyfunctional monomer. Parts, more preferably 50 parts by weight to 85 parts by weight.

B-3. Photopolymerization initiator The photosensitive resin composition preferably contains two or more photopolymerization initiators.

  In one embodiment, as a photoinitiator, the 1st photoinitiator and the 2nd photoinitiator which have maximum absorption wavelength in a different wavelength range are used. By using two or more kinds of photopolymerization initiators having maximum absorption wavelengths in different wavelength ranges, ultraviolet light can be used efficiently during exposure. As a result, a photo spacer having a lower portion that is not thinner than the upper portion, that is, a non-reverse tapered shape, is formed. The non-reverse tapered photo spacer has excellent substrate adhesion, high elastic recovery rate and high breaking strength even if the diameter is small. Further, the photospacer can prevent bubbles from being mixed into the liquid crystal layer, and can contribute to the improvement of the display performance of the display device.

  The first photopolymerization initiator preferably has a maximum absorption wavelength at a wavelength of 290 nm to 380 nm, more preferably has a maximum absorption wavelength at a wavelength of 295 nm to 350 nm, and more preferably has a maximum absorption wavelength at a wavelength of 295 nm to 340 nm. Have. By using such a first photopolymerization initiator, a non-reverse tapered photo spacer can be obtained. When a photopolymerization initiator having a maximum absorption wavelength on the wavelength side higher than 380 nm is used, it is difficult to control the thickness of the photo spacer, and a photo spacer that is too thick may be formed. In the present invention, the “maximum absorption wavelength” refers to the wavelength of maximum absorption at which the absorbance measured at an optical path length of 1 cm is 0.5 or more for a photopolymerization initiator solution having a concentration of 0.001% by weight.

式（１２）中、Ｘ^１およびＸ^２はそれぞれ独立して、メチル基、エチル基、ベンジル基または４−メチルベンジル基であり、好ましくはメチル基である。−ＮＸ^３Ｘ^４はジメチルアミノ基、ジエチルアミノ基またはモルフォリノ基であり、好ましくはジメチルアミノ基またはモルフォリノ基であり、より好ましくはモルフォリノ基である。Ｘ^５は、水素原子、炭素数が１〜８のアルキル基、炭素数が１〜８のアルコキシ基、炭素数が１〜８のアルキルチオ基、ジメチルアミノ基、またはモルフォリノ基であり、好ましくは炭素数が１〜８のアルキルチオ基またはモルフォリノ基であり、より好ましくは炭素数が１〜３のアルキルチオ基またはモルフォリノ基であり、さらに好ましくはメチルチオ基である。 As the first photopolymerization initiator, an α-aminoketone compound is preferably used, and more preferably an α-aminoketone compound represented by the general formula (12) is used. If such a compound is used, a photo spacer having a non-inverted taper shape and a small diameter can be obtained.

In formula (12), X ¹ and X ² are each independently a methyl group, an ethyl group, a benzyl group or a 4-methylbenzyl group, preferably a methyl group. —NX ³ X ⁴ is a dimethylamino group, a diethylamino group or a morpholino group, preferably a dimethylamino group or a morpholino group, more preferably a morpholino group. X ⁵ is a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an alkylthio group having 1 to 8 carbon atoms, a dimethylamino group, or a morpholino group, preferably carbon It is an alkylthio group or morpholino group having 1 to 8 carbon atoms, more preferably an alkylthio group or morpholino group having 1 to 3 carbon atoms, and further preferably a methylthio group.

  Specific examples of the α-aminoketone compound include 2-dimethylamino-2-methyl-1-phenylpropan-1-one, 2-diethylamino-2-methyl-1-phenylpropan-1-one, and 2-methyl. 2-morpholino-1-phenylpropan-1-one, 2-dimethylamino-2-methyl-1- (4-methylphenyl) propan-1-one, 2-dimethylamino-1- (4-ethylphenyl) 2-methylpropan-1-one, 2-dimethylamino-1- (4-isopropylphenyl) -2-methylpropan-1-one, 1- (4-butylphenyl) -2-dimethylamino-2-methyl Propan-1-one, 2-dimethylamino-1- (4-methoxyphenyl) -2-methylpropan-1-one, 2-dimethylamino-2-methyl-1 (4-methylthiophenyl) propan-1-one, 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpho Linophenyl) -butan-1-one, 2-benzyl-2-dimethylamino-1- (4-dimethylaminophenyl) -butan-1-one, 2-dimethylamino-2-[(4-methylphenyl) methyl ] -1- [4- (4-morpholinyl) phenyl] -1-butanone and the like. These compounds may be used alone or in combination of two or more. Among them, 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butane-1 is preferable. -One or 2-dimethylamino-2-[(4-methylphenyl) methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone, more preferably 2-methyl-1- (4 -Methylthiophenyl) -2-morpholinopropan-1-one. If 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one is used as the first photopolymerization initiator, a photospacer having a non-reverse taper shape and a small diameter is obtained. be able to.

  A commercially available product may be used as the first photopolymerization initiator. Examples of the commercially available first photopolymerization initiator include trade names “Irgacure 907”, “Irgacure 369”, and “Irgacure 379” manufactured by BASF Japan.

  The content ratio of the first photopolymerization initiator is preferably 0.1 parts by weight to 30 parts by weight, more preferably 0.1 parts by weight with respect to 100 parts by weight of the total weight of the alkali-soluble resin and the polyfunctional monomer. 5 to 10 parts by weight, more preferably 1.0 to 5 parts by weight.

  The second photopolymerization initiator preferably has a maximum absorption wavelength at a wavelength of 230 nm to 290 nm, more preferably has a maximum absorption wavelength at a wavelength of 240 nm to 280 nm, and more preferably a maximum absorption wavelength at a wavelength of 250 nm to 270 nm. Have

式（１３）中、Ｘ^６は水素原子、炭素数が１〜１０のアルキル基、または炭素数が１〜１０のアルコキシ基であり、好ましくは水素原子、炭素数が１〜５のアルキル基または炭素数が１〜５のアルコキシ基であり、より好ましくは水素原子または炭素数が１〜２のアルコキシ基である。Ｘ^７およびＸ^８はそれぞれ独立して、水素原子または炭素数が１〜１０のアルキル基であり、好ましくは炭素数が１〜５のアルキル基であり、より好ましくはメチル基である。また、Ｘ^７とＸ^８とが結合して炭素数が４〜８（好ましくは６〜８、より好ましくは６）のシクロアルキル基を形成していてもよい。
式（１４）中、Ｘ^９〜Ｘ^１２はそれぞれ独立して、水素原子または炭素数が１〜１０のアルキル基であり、好ましくは炭素数が１〜５のアルキル基であり、より好ましくはメチル基である。また、Ｘ^９とＸ^１０、および／またはＸ^１１とＸ^１２とが結合して炭素数が４〜８のシクロアルキル基を形成していてもよい。
上記アルキル基、アルコキシ基、アルキル基およびシクロアルキル基は、置換基を有していてもよい。該置換基としては、例えば、水酸基、カルボキシル基、スルホ基、シアノ基、ハロゲン原子等が挙げられる。 As the second photopolymerization initiator, an α-hydroxyketone compound is preferably used, more preferably an α-hydroxyketone compound represented by the general formula (13) or the general formula (14) is used. More preferably, an α-hydroxyketone compound represented by the general formula (14) is used. If such a compound is used, a photo spacer having a non-inverted taper shape and a small diameter can be obtained.

In Formula (13), X ⁶ is a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an alkoxy group having 1 to 10 carbon atoms, preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or It is a C1-C5 alkoxy group, More preferably, it is a hydrogen atom or a C1-C2 alkoxy group. X ⁷ and X ⁸ are each independently a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, preferably an alkyl group having 1 to 5 carbon atoms, and more preferably a methyl group. X ⁷ and X ⁸ may be bonded to each other to form a cycloalkyl group having 4 to 8 carbon atoms (preferably 6 to 8, more preferably 6).
In formula (14), X ^{9 to} X ¹² are each independently a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, preferably an alkyl group having 1 to 5 carbon atoms, more preferably methyl. It is a group. X ⁹ and X ¹⁰ and / or X ¹¹ and X ¹² may be bonded to each other to form a cycloalkyl group having 4 to 8 carbon atoms.
The alkyl group, alkoxy group, alkyl group and cycloalkyl group may have a substituent. Examples of the substituent include a hydroxyl group, a carboxyl group, a sulfo group, a cyano group, and a halogen atom.

  Specific examples of the α-hydroxyketone compound include 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2-hydroxy-2-methyl-1-phenylbutan-1-one, 1- ( 4-methylphenyl) -2-hydroxy-2-methylpropan-1-one, 1- (4-isopropylphenyl) -2-methylpropan-1-one, 1- (4-butylphenyl) -2-hydroxy- 2-methylpropan-1-one, 2-hydroxy-2-methyl-1- (4-octylphenyl) propan-1-one, 1- (4-dodecylphenyl) -2-methylpropan-1-one, 1 -(4-methoxyphenyl) -2-methylpropan-1-one, 1- (4-methylthiophenyl) -2-methylpropan-1-one, 1- (4-chlorophenyl)- -Hydroxy-2-methylpropan-1-one, 1- (4-bromophenyl) -2-hydroxy-2-methylpropan-1-one, 2-hydroxy-1- (4-hydroxyphenyl) -2-methyl Propan-1-one, 1- (4-dimethylaminophenyl) -2-hydroxy-2-methylpropan-1-one, 1- (4-carboethoxyphenyl) -2-hydroxy-2-methylpropane-1- ON, 1-hydroxycyclohexyl phenyl ketone, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1- {4- [ 4- (2-hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-methyl-propan-1-one and the like. These compounds may be used alone or in combination of two or more. Among them, 1-hydroxycyclohexyl phenyl ketone, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one, or 2-hydroxy-1- { 4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-methyl-propan-1-one, more preferably 2-hydroxy-1- {4- [4- ( 2-hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-methyl-propan-1-one. If 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-methyl-propan-1-one is used as the second photopolymerization initiator A photo spacer having a non-inverted taper shape and a small diameter can be obtained.

  A commercially available product may be used as the second photopolymerization initiator. Examples of the commercially available second photopolymerization initiator include trade names “Irgacure 184”, “Irgacure 2959”, “Irgacure 127”, and “Darocure 1173” manufactured by BASF Japan.

  The content ratio of the second photopolymerization initiator is preferably 0.01 parts by weight to 30 parts by weight with respect to 100 parts by weight of the total weight of the alkali-soluble resin and the polyfunctional monomer, and more preferably It is 0.05 weight part-10 weight part, More preferably, it is 0.07 weight part-1 weight part.

  The content ratio of the second photopolymerization initiator is preferably 5% by weight to 40% by weight with respect to the total weight of the first photopolymerization initiator and the second photopolymerization initiator. More preferably, it is 5 to 30% by weight, and further preferably 5 to 20% by weight. If it is such a range, the photo-spacer which is excellent in board | substrate adhesiveness, and has a high elastic recovery factor and fracture strength can be obtained.

  The total content of the first photopolymerization initiator and the second photopolymerization initiator is preferably 0.5 parts by weight to 100 parts by weight of the total weight of the alkali-soluble resin and the polyfunctional monomer. 50 parts by weight, more preferably 1 part by weight to 10 parts by weight, still more preferably 1.5 parts by weight to 5 parts by weight.

  In addition to the first photopolymerization initiator and the second photopolymerization initiator, a photopolymerization initiation assistant can be used in combination, and the photopolymerization initiation assistant can be used in a plurality of combinations. Specific examples of the photopolymerization initiation assistant include 1,3,5-tris (3-mercaptopropionyloxyethyl) -isocyanurate, 1,3,5-tris (3-mercaptobutyloxyethyl) -isocyanurate (Showa Electric Works, Karenz MT (registered trademark) NR1), trimethylolpropane tris (trifunctional thiol compounds such as 3-mercaptopropionate; pentaerythritol tetrakis (3-mercaptopropionate), pentaerythritol tetrakis (3-mercapto) (Butylate) (Showa Denko Co., Ltd., Karenz MT (registered trademark) PE1) and other tetrafunctional thiol compounds; difunctional thiol compounds such as dipentaerythritol hexakis (3-propionate)

B-4. Solvent The photosensitive resin composition may contain any appropriate solvent. Examples of the solvent include ethers such as tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, and diethylene glycol dimethyl ether; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ethyl acetate, butyl acetate, propylene glycol monomethyl ether acetate, 3-methoxy Esters such as butyl acetate; Alcohols such as methanol, ethanol, isopropanol, n-butanol, ethylene glycol monomethyl ether, and propylene glycol monomethyl ether; Aromatic hydrocarbons such as toluene, xylene, and ethylbenzene; Chloroform, dimethyl sulfoxide, and the like Can be mentioned. The amount of the solvent can be set to any appropriate amount depending on the desired viscosity of the photosensitive resin composition.

B-5. Additives The photosensitive resin composition may contain any appropriate additive as required. As additives, for example, fillers such as aluminum hydroxide, talc, clay, barium sulfate, dyes, pigments, antifoaming agents, coupling agents, leveling agents, sensitizers, mold release agents, lubricants, plasticizers, Antioxidants, ultraviolet absorbers, flame retardants, polymerization inhibitors, thickeners, dispersants and the like can be mentioned.

  In one embodiment, the photosensitive resin composition includes a UV absorber. If a photosensitive resin composition containing a UV absorber is used, a photo spacer having a small difference in diameter between the upper and lower sides can be obtained, and the photo spacer can be formed into a thin column. The photospacer of the present invention has a sufficient breaking strength even if it is thin.

  When the photosensitive resin composition contains a UV absorber, the content of the UV absorber is preferably 0.05 parts by weight to 100 parts by weight of the total weight of the alkali-soluble resin and the polyfunctional monomer. 10 parts by weight, more preferably 0.1 parts by weight to 5 parts by weight, and still more preferably 0.2 parts by weight to 3 parts by weight. When the content ratio of the UV absorber exceeds 10 parts by weight, a non-reverse tapered photo spacer may not be obtained.

C. Method for Forming Photospacer The photospacer of the present invention can be obtained using the above photosensitive resin composition. If the said photosensitive resin composition is used, it is excellent in board | substrate adhesiveness and can form a photo spacer with a high elastic recovery rate and a high fracture strength.

  The photospacer can be formed by photolithography. Specifically, after the photosensitive resin composition is applied to a substrate and dried, a photomask is placed on the obtained coating film to expose it, the coating film is cured, and then developed to obtain a photo Spacers can be formed. According to photolithography, a photo spacer can be formed at an arbitrary position. For example, in a liquid crystal display device, a photo spacer is formed only on a black matrix to prevent display characteristics from being deteriorated due to the spacer. can do.

  Examples of the method for applying the photosensitive resin composition include a method using a spin coater, bar coater, gravure coater, roll coater, knife coater, applicator and the like. The drying temperature is preferably 40 ° C to 200 ° C, more preferably 70 ° C to 100 ° C. The drying time is preferably 1 minute to 30 minutes, more preferably 2 minutes to 10 minutes.

  The photomask is arranged at any appropriate position depending on the desired size of the photospacer. The photomask is disposed on the top of the coating film, and the distance between the coating film and the photomask is preferably 0 μm to 500 μm, more preferably 10 μm to 400 μm, still more preferably 20 μm to 300 μm, and particularly preferably 30 μm. ~ 200 μm.

UV radiation intensity during the exposure (365 nm intensity equivalent), preferably ^{10mJ / cm 2 ~200mJ / cm 2} , more preferably ^{20mJ / cm 2 ~150mJ / cm 2} , more preferably 30 mJ / cm ² ˜100 mJ / cm ² .

  In the development, an alkaline aqueous solution is preferably used. This is because high-sensitivity development can be performed with less environmental burden. As the alkaline component, for example, potassium hydroxide, sodium hydroxide, sodium carbonate or the like is used. The alkali concentration of the aqueous alkali solution is preferably 0.01% to 5% by weight, more preferably 0.02% to 3% by weight, and still more preferably 0.03% to 1% by weight. . If it is such a range, the said photosensitive resin composition can be melt | dissolved appropriately and a photo spacer can be formed with sufficient developability. A surfactant may be further added to the alkaline aqueous solution.

  You may post-bake after image development. The heating temperature during post-baking is preferably 150 ° C to 300 ° C, more preferably 180 ° C to 250 ° C. The heating time is preferably 10 minutes to 90 minutes, more preferably 20 minutes to 60 minutes. When the said photosensitive resin composition contains the acrylic resin which has a repeating unit (B) which has a 2 or more oxyalkylene group in a side chain, a photo spacer with a high crosslinking density can be formed by post-baking.

  The photospacer of the present invention can be suitably used as a spacer for a liquid crystal display, more specifically, a liquid crystal cell of a liquid crystal display.

  Hereinafter, the present invention will be described more specifically by way of examples. However, the present invention is not limited to these examples. The evaluation methods in the examples are as follows.

(1) Weight average molecular weight: Mw
GPC (HLC-8220GPC, manufactured by Tosoh Corporation) was used as an eluent, and TSKgel SuperHZM-N (manufactured by Tosoh Corporation) was used as a column for the measurement.
(2) Solid content About 0.3 g of the copolymer solution prepared in the production example was weighed into an aluminum cup, dissolved by adding about 1 g of acetone, and then naturally dried at room temperature. Thereafter, using a hot air dryer (trade name: PHH-101, manufactured by ESPEC Corp.), it was dried at 140 ° C. for 3 hours, then allowed to cool in a desiccator, and the weight was measured. From the weight loss, the weight of the solid content (acrylic resin) of the polymer solution was calculated.
(3) Acid value 1.5 g of the copolymer solution prepared in the production example was precisely weighed, dissolved in a mixed solvent of 90 g of acetone and 10 g of water, and titrated with a 0.1 N aqueous KOH solution. Titration was performed using an automatic titrator (trade name: COM-555, manufactured by Hiranuma Sangyo Co., Ltd.), and the acid value per 1 g of polymer was determined from the solid content concentration (mgKOH / g).

(4) Development residue After development, the presence or absence of undissolved residue of the photosensitive resin composition was evaluated by visual observation.
(5) Adhesiveness of photo spacer The presence or absence of defects in the formed photo spacer was visually observed and evaluated according to the following criteria.
○: No defect and very good adhesion △: Partial defect and good adhesion ×: All defects and poor adhesion (6) Compression ratio of photospacer Measurement was performed using a machine (trade name: HM2000, manufactured by Fisher Instruments). With a 100 μm square planar indenter, both the loading speed and the unloading speed are set to 4.7 mN / sec, the load up to 80 mN is loaded, the load is unloaded to 0.49 mN, and the load-deformation curve and the unloading during loading are applied. A load-deformation curve at the time was created. At this time, the amount of deformation at a load of 80 mN at the time of loading was L1, and the compression rate was calculated by the following formula.
Compression rate (%) = L1 × 100 / Spacer height (7) Elastic recovery rate of the photo spacer The elastic recovery rate of the photo spacer was measured using a micro compression tester (trade name: HM2000, manufactured by Fisher Instruments). It was measured. With a 100 μm square planar indenter, both the loading speed and the unloading speed are set to 4.7 mN / sec, the load up to 80 mN is loaded, the load is unloaded to 0.49 mN, and the load-deformation curve and the unloading during loading are applied. A load-deformation curve at the time was created. At this time, the amount of deformation at a load of 80 mN during loading was L1, and the amount of deformation at a load of 0.49 mN during unloading was L2, and the elastic recovery rate was calculated by the following equation.
Elastic recovery rate (%) = (L1-L2) × 100 / L1
(8) Fracture strength of the photo spacer The break strength of the photo spacer was measured using a micro compression tester (trade name: HM2000, manufactured by Fisher Instruments). Using a 100 μm square planar indenter, the load speed and the unloading speed were both set to 4.7 mN / sec, a load up to 300 mN was applied, and the load when the spacer was broken was read from the load-deformation curve.
(9) Thickness (horizontal cross-sectional diameter at the bottom) and height of the photospacer The diameter and height at the bottom of the photospacer were measured using a laser microscope (trade name “VK-9700”, manufactured by Keyence Corporation). Measured.
(10) Shape of photo spacer (non-reverse tapered shape / reverse tapered shape)
The evaluation of whether the shape of the photo spacer is a non-reverse tapered shape or a reverse tapered shape is performed using FE-SEM (trade name “S-4800”, manufactured by Hitachi, Ltd.) L × 1/2) The diameter D1 of the separated portion H1 and (the height of the photospacer L × 1/4) the diameter D2 of the separated portion H2 are measured, and the horizontal section at H1 is measured from the diameters D1 and D2. The calculation was performed by calculating the horizontal cross-sectional area A2 at the areas A1 and H2. A case where A2 / A1 is 1 or more is a non-inverted taper shape.

[Production Example 1]
A separable flask equipped with a cooling tube was prepared as a reaction vessel. On the other hand, in the monomer dropping tank, as a monomer composition, 15 g of benzylmaleimide (BzMI), 44.5 g of acrylic acid (AA), 1: 1 (molar ratio) of 1 mol ethoxylated phenylphenol acrylate and 2 mol ethoxylated phenylphenol acrylate ) Mixture (trade name “OPPE”, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., hereinafter also referred to as OPPE) 40.5 g, t-butylperoxy-2-ethylhexanoate (trade name “Perbutyl (registered trademark) O”, Japan 2 g manufactured by Yushi Co., Ltd. (hereinafter also referred to as “PBO”), 42 g of propylene glycol methyl ether acetate (PGMEA) and 18 g of propylene glycol monomethyl ether (PGME) were added and mixed with stirring. Further, 2 g of dodecyl mercaptan (nDM), 18 g of PGMEA and 8 g of PGMEA were added as a chain transfer agent solution into the chain transfer agent dropping tank and mixed with stirring.
The reaction vessel was charged with 98 g of PGMEA and 42 g of PGME, purged with nitrogen, and then heated in an oil bath while stirring to raise the temperature of the reaction vessel to 90 ° C. After the temperature of the reaction vessel was stabilized at 90 ° C., the monomer composition and the chain transfer agent solution were added dropwise. The monomer composition and the chain transfer agent solution were added dropwise over 180 minutes while maintaining the temperature at 90 ° C. PBO 0.5g was added 30 minutes after the completion of the dropping. After another 30 minutes, the temperature of the reaction vessel was raised to 115 ° C. After maintaining at 115 ° C. for 1.5 hours, a gas introduction tube was attached to the separable flask, and bubbling of oxygen / nitrogen = 5/95 (v / v) mixed gas was started. Next, 69 g of glycidyl methacrylate (GMA) in the reaction vessel, 0.3 g of 6-tert-butyl-2,4-xylenol (trade name “Topanol”, manufactured by Tokyo Chemical Industry Co., Ltd.) as a polymerization inhibitor, and dimethylbenzyl as a catalyst Amine (DMBA) 0.5 g, PGMEA 16 g and PGME 6 g were charged and reacted at 110 ° C. for 1 hour and 115 ° C. for 8 hours. Then, it cooled to room temperature and obtained the copolymer solution (A-1) containing 39.4 weight% of acrylic resins. The weight average molecular weight (Mw) of the acrylic resin was 17200, and the acid value was 55 mgKOH / g. The production conditions, solid content concentration, weight average molecular weight (Mw) and acid value of the copolymer solution are shown in Table 1 together with Production Examples 2 to 17.

[Production Example 2]
A separable flask equipped with a cooling tube was prepared as a reaction vessel. On the other hand, 15 g of BzMI, 55 g of AA, 30 g of OPPE, 2 g of PBO, 30 g of PGMEA, and 30 g of PGME were added as a monomer composition into the monomer dropping tank and mixed with stirring. Moreover, nDM2g, PGMEA13g, and PGMME13g were thrown into the chain transfer agent dripping tank as a chain transfer agent solution, and it stirred and mixed.
The reaction vessel was charged with 98 g of PGMEA and 42 g of PGME, purged with nitrogen, and then heated in an oil bath while stirring to raise the temperature of the reaction vessel to 90 ° C. After the temperature of the reaction vessel was stabilized at 90 ° C., the monomer composition and the chain transfer agent solution were added dropwise. The monomer composition and the chain transfer agent solution were added dropwise over 180 minutes while maintaining the temperature at 90 ° C. PBO 0.5g was added 30 minutes after the completion of the dropping. After another 30 minutes, the temperature of the reaction vessel was raised to 115 ° C. After maintaining at 115 ° C. for 1.5 hours, a gas introduction tube was attached to the separable flask, and bubbling of oxygen / nitrogen = 5/95 (v / v) mixed gas was started. Next, 69 g of GMA, 0.3 g of 6-tert-butyl-2,4-xylenol (trade name “Topanol”, manufactured by Tokyo Chemical Industry Co., Ltd.) as a polymerization inhibitor, and 0.5 g of DMBA, 11 g of PGMEA, and 11 g of PGME as catalysts are placed in a reaction vessel. The reaction was performed at 110 ° C. for 1 hour and at 115 ° C. for 8 hours. Then, it cooled to room temperature and obtained the copolymer solution (A-2) containing 39.3 weight% of acrylic resins. The weight average molecular weight (Mw) of the acrylic resin was 18000, and the acid value was 103 mgKOH / g.

[Production Example 3]
A separable flask equipped with a cooling tube was prepared as a reaction vessel. On the other hand, as a monomer composition, 15 g of BzMI, 42 g of AA, 43 g of OPPE, 2 g of PBO, 42 g of PGMEA, and 18 g of PGME were stirred and mixed in the monomer dropping tank. Further, 2 g of nDM, 18 g of PGMEA, and 8 g of PGME were added as a chain transfer agent solution into the chain transfer agent dropping tank, and mixed with stirring.
The reaction vessel was charged with 98 g of PGMEA and 42 g of PGME, purged with nitrogen, and then heated in an oil bath while stirring to raise the temperature of the reaction vessel to 90 ° C. After the temperature of the reaction vessel was stabilized at 90 ° C., the monomer composition and the chain transfer agent solution were added dropwise. The monomer composition and the chain transfer agent solution were added dropwise over 180 minutes while maintaining the temperature at 90 ° C. PBO 0.5g was added 30 minutes after the completion of the dropping. After another 30 minutes, the temperature of the reaction vessel was raised to 115 ° C. After maintaining at 115 ° C. for 1.5 hours, a gas introduction tube was attached to the separable flask, and bubbling of oxygen / nitrogen = 5/95 (v / v) mixed gas was started. Next, 69 g of GMA, 0.3 g of 6-tert-butyl-2,4-xylenol (trade name “Topanol”, manufactured by Tokyo Chemical Industry Co., Ltd.) as a polymerization inhibitor, and 0.5 g of DMBA, 16 g of PGMEA, and 6 g of PGME as a catalyst are added to the reaction vessel. The reaction was performed at 110 ° C. for 1 hour and at 115 ° C. for 8 hours. Then, it cooled to room temperature and obtained the copolymer solution (A-3) containing 39.0 weight% of acrylic resins. The weight average molecular weight (Mw) of the acrylic resin was 18200, and the acid value was 44 mgKOH / g.

[Production Example 4]
A separable flask equipped with a cooling tube was prepared as a reaction vessel. On the other hand, as a monomer composition, 15 g of BzMI, 44.5 g of AA, 40.5 g of OPPE, 2 g of PBO, 42 g of PGMEA, and 18 g of PGME were stirred and mixed in the monomer dropping tank. Moreover, nDM1.2g, PGMEA18g, and PGMEA8g were thrown into the chain transfer agent dripping tank as a chain transfer agent solution, and it stirred and mixed.
The reaction vessel was charged with 98 g of PGMEA and 42 g of PGME, purged with nitrogen, and then heated in an oil bath while stirring to raise the temperature of the reaction vessel to 90 ° C. After the temperature of the reaction vessel was stabilized at 90 ° C., the monomer composition and the chain transfer agent solution were added dropwise. The monomer composition and the chain transfer agent solution were added dropwise over 180 minutes while maintaining the temperature at 90 ° C. PBO 0.5g was added 30 minutes after the completion of the dropping. After another 30 minutes, the temperature of the reaction vessel was raised to 115 ° C. After maintaining at 115 ° C. for 1.5 hours, a gas introduction tube was attached to the separable flask, and bubbling of oxygen / nitrogen = 5/95 (v / v) mixed gas was started. Next, 69 g of GMA, 0.3 g of 6-tert-butyl-2,4-xylenol (trade name “Topanol”, manufactured by Tokyo Chemical Industry Co., Ltd.) as a polymerization inhibitor, and 0.5 g of DMBA, 16 g of PGMEA, and 6 g of PGME as a catalyst are added to the reaction vessel. The reaction was performed at 110 ° C. for 1 hour and at 115 ° C. for 8 hours. Then, it cooled to room temperature and obtained the copolymer solution (A-4) containing 39.5 weight% of acrylic resins. The weight average molecular weight (Mw) of the acrylic resin was 25200, and the acid value was 56 mgKOH / g.

[Production Example 5]
A separable flask equipped with a cooling tube was prepared as a reaction vessel. On the other hand, as a monomer composition, 15 g of BzMI, 44.5 g of AA, 40.5 g of OPPE, 2 g of PBO, 42 g of PGMEA, and 18 g of PGME were stirred and mixed in the monomer dropping tank. Moreover, nDM5g, PGMEA18g, and PGME8g were thrown into the chain transfer agent dripping tank as a chain transfer agent solution, and it stirred and mixed.
The reaction vessel was charged with 98 g of PGMEA and 42 g of PGME, purged with nitrogen, and then heated in an oil bath while stirring to raise the temperature of the reaction vessel to 90 ° C. After the temperature of the reaction vessel was stabilized at 90 ° C., the monomer composition and the chain transfer agent solution were added dropwise. The monomer composition and the chain transfer agent solution were added dropwise over 180 minutes while maintaining the temperature at 90 ° C. PBO 0.5g was added 30 minutes after the completion of the dropping. After another 30 minutes, the temperature of the reaction vessel was raised to 115 ° C. After maintaining at 115 ° C. for 1.5 hours, a gas introduction tube was attached to the separable flask, and bubbling of oxygen / nitrogen = 5/95 (v / v) mixed gas was started. Next, 69 g of GMA, 0.3 g of 6-tert-butyl-2,4-xylenol (trade name “Topanol”, manufactured by Tokyo Chemical Industry Co., Ltd.) as a polymerization inhibitor, and 0.5 g of DMBA, 16 g of PGMEA, and 6 g of PGME as a catalyst are added to the reaction vessel. The reaction was performed at 110 ° C. for 1 hour and at 115 ° C. for 8 hours. Then, it cooled to room temperature and obtained the copolymer solution (A-5) containing 38.8 weight% of acrylic resins. The weight average molecular weight (Mw) of the acrylic resin was 10400, and the acid value was 55 mgKOH / g.

[Production Example 6]
A separable flask equipped with a cooling tube was prepared as a reaction vessel. On the other hand, 10 g of BzMI, 76 g of AA, 14 g of OPPE, 2 g of PBO, 18 g of PGMEA, and 42 g of PGME were added as a monomer composition into the monomer dropping tank and mixed with stirring. Further, 1.5 g of nDM, 8 g of PGMEA and 18 g of PGMEA were added as a chain transfer agent solution into the chain transfer agent dropping tank and mixed with stirring.
The reaction vessel was charged with 42 g of PGMEA and 98 g of PGME, purged with nitrogen, and then heated in an oil bath while stirring to raise the temperature of the reaction vessel to 90 ° C. After the temperature of the reaction vessel was stabilized at 90 ° C., the monomer composition and the chain transfer agent solution were added dropwise. The monomer composition and the chain transfer agent solution were added dropwise over 180 minutes while maintaining the temperature at 90 ° C. PBO 0.5g was added 30 minutes after the completion of the dropping. After another 30 minutes, the temperature of the reaction vessel was raised to 115 ° C. After maintaining at 115 ° C. for 1.5 hours, a gas introduction tube was attached to the separable flask, and bubbling of oxygen / nitrogen = 5/95 (v / v) mixed gas was started. Next, 124 g of GMA, 0.3 g of 6-tert-butyl-2,4-xylenol (trade name “Topanol”, manufactured by Tokyo Chemical Industry Co., Ltd.) as a polymerization inhibitor, and 0.7 g of DMBA, 0.7 g of PGMEA, 32 g of PGMEA, and 74 g of PGME are used as a reaction vessel. The reaction was performed at 110 ° C. for 1 hour and at 115 ° C. for 12 hours. Then, it cooled to room temperature and obtained the copolymer solution (A-6) containing 39.6 weight% of acrylic resins. The weight average molecular weight (Mw) of the acrylic resin was 19300, and the acid value was 54 mgKOH / g.

[Production Example 7]
A separable flask equipped with a cooling tube was prepared as a reaction vessel. On the other hand, 15 g of BzMI, 23 g of AA, 62 g of OPPE, 2 g of PBO, 42 g of PGMEA, and 18 g of PGME were added as a monomer composition to the monomer dropping tank and mixed with stirring. Further, 2 g of nDM, 18 g of PGMEA, and 8 g of PGME were added as a chain transfer agent solution into the chain transfer agent dropping tank, and mixed with stirring.
The reaction vessel was charged with 98 g of PGMEA and 42 g of PGME, purged with nitrogen, and then heated in an oil bath while stirring to raise the temperature of the reaction vessel to 90 ° C. After the temperature of the reaction vessel was stabilized at 90 ° C., the monomer composition and the chain transfer agent solution were added dropwise. The monomer composition and the chain transfer agent solution were added dropwise over 180 minutes while maintaining the temperature at 90 ° C. PBO 0.5g was added 30 minutes after the completion of the dropping. After another 30 minutes, the temperature of the reaction vessel was raised to 115 ° C. After maintaining at 115 ° C. for 1.5 hours, a gas introduction tube was attached to the separable flask, and bubbling of oxygen / nitrogen = 5/95 (v / v) mixed gas was started. Next, 30 g of GMA, 0.3 g of 6-tert-butyl-2,4-xylenol (trade name “Topanol”, manufactured by Tokyo Chemical Industry Co., Ltd.) as a polymerization inhibitor and 0.5 g of DMBA as a catalyst were charged in a reaction vessel at 110 ° C. For 1 hour and at 115 ° C. for 8 hours. Then, it cooled to room temperature and obtained the copolymer solution (A-7) containing 35.0 weight% of acrylic resins. The weight average molecular weight (Mw) of the acrylic resin was 17000, and the acid value was 56 mgKOH / g.

[Production Example 8]
A separable flask equipped with a cooling tube was prepared as a reaction vessel. On the other hand, 15 g of cyclohexylmaleimide (CHMI), 44.5 g of AA, 40.5 g of OPPE, 2 g of PBO, 42 g of PGMEA, and 18 g of PGME were added as a monomer composition to the monomer dropping tank and mixed with stirring. Further, 2 g of nDM, 18 g of PGMEA, and 8 g of PGME were added as a chain transfer agent solution into the chain transfer agent dropping tank, and mixed with stirring.
The reaction vessel was charged with 98 g of PGMEA and 42 g of PGME, purged with nitrogen, and then heated in an oil bath while stirring to raise the temperature of the reaction vessel to 90 ° C. After the temperature of the reaction vessel was stabilized at 90 ° C., the monomer composition and the chain transfer agent solution were added dropwise. The monomer composition and the chain transfer agent solution were added dropwise over 180 minutes while maintaining the temperature at 90 ° C. PBO 0.5g was added 30 minutes after the completion of the dropping. After another 30 minutes, the temperature of the reaction vessel was raised to 115 ° C. After maintaining at 115 ° C. for 1.5 hours, a gas introduction tube was attached to the separable flask, and bubbling of oxygen / nitrogen = 5/95 (v / v) mixed gas was started. Next, 69 g of GMA, 0.3 g of 6-tert-butyl-2,4-xylenol (trade name “Topanol”, manufactured by Tokyo Chemical Industry Co., Ltd.) as a polymerization inhibitor, and 0.5 g of DMBA, 16 g of PGMEA, and 6 g of PGME as a catalyst are added to the reaction vessel. The reaction was performed at 110 ° C. for 1 hour and at 115 ° C. for 8 hours. Then, it cooled to room temperature and obtained the copolymer solution (A-8) containing 39.0 weight% of acrylic resins. The weight average molecular weight (Mw) of the acrylic resin was 17500, and the acid value was 54 mgKOH / g.

[Production Example 9]
A separable flask equipped with a cooling tube was prepared as a reaction vessel. On the other hand, in a monomer dropping tank, 15 g of dimethyl-2,2 ′-[oxybis (methylene)] bis-2-propenoate (MD), 44.5 g of AA, 40.5 g of OPPE, 2 g of PBO, 42 g of PGMEA and 18 g of PGME were used as a monomer composition. The mixture was stirred and mixed. Further, 2 g of nDM, 18 g of PGMEA, and 8 g of PGME were added as a chain transfer agent solution into the chain transfer agent dropping tank, and mixed with stirring.
The reaction vessel was charged with 98 g of PGMEA and 42 g of PGME, purged with nitrogen, and then heated in an oil bath while stirring to raise the temperature of the reaction vessel to 90 ° C. After the temperature of the reaction vessel was stabilized at 90 ° C., the monomer composition and the chain transfer agent solution were added dropwise. The monomer composition and the chain transfer agent solution were added dropwise over 180 minutes while maintaining the temperature at 90 ° C. PBO 0.5g was added 30 minutes after the completion of the dropping. After another 30 minutes, the temperature of the reaction vessel was raised to 115 ° C. After maintaining at 115 ° C. for 1.5 hours, a gas introduction tube was attached to the separable flask, and bubbling of oxygen / nitrogen = 5/95 (v / v) mixed gas was started. Next, 69 g of GMA, 0.3 g of 6-tert-butyl-2,4-xylenol (trade name “Topanol”, manufactured by Tokyo Chemical Industry Co., Ltd.) as a polymerization inhibitor, and 0.5 g of DMBA, 16 g of PGMEA, and 6 g of PGME as a catalyst are added to the reaction vessel. The reaction was performed at 110 ° C. for 1 hour and at 115 ° C. for 8 hours. Then, it cooled to room temperature and obtained the copolymer solution (A-9) containing 38.8 weight% of acrylic resins. The weight average molecular weight (Mw) of the acrylic resin was 17000, and the acid value was 53 mgKOH / g.

[Production Example 10]
A separable flask equipped with a cooling tube was prepared as a reaction vessel. On the other hand, 15 g of (α-allyloxymethyl) methyl acrylate (AMA), 44.5 g of AA, 40.5 g of OPPE, 2 g of PBO, 42 g of PGMEA and 18 g of PGME were added as a monomer composition and mixed with stirring. Further, 2 g of nDM, 18 g of PGMEA, and 8 g of PGME were added as a chain transfer agent solution into the chain transfer agent dropping tank, and mixed with stirring.
The reaction vessel was charged with 98 g of PGMEA and 42 g of PGME, purged with nitrogen, and then heated in an oil bath while stirring to raise the temperature of the reaction vessel to 90 ° C. After the temperature of the reaction vessel was stabilized at 90 ° C., the monomer composition and the chain transfer agent solution were added dropwise. The monomer composition and the chain transfer agent solution were added dropwise over 180 minutes while maintaining the temperature at 90 ° C. PBO 0.5g was added 30 minutes after the completion of the dropping. After another 30 minutes, the temperature of the reaction vessel was raised to 115 ° C. After maintaining at 115 ° C. for 1.5 hours, a gas introduction tube was attached to the separable flask, and bubbling of oxygen / nitrogen = 5/95 (v / v) mixed gas was started. Next, 69 g of GMA, 0.3 g of 6-tert-butyl-2,4-xylenol (trade name “Topanol”, manufactured by Tokyo Chemical Industry Co., Ltd.) as a polymerization inhibitor, and 0.5 g of DMBA, 16 g of PGMEA, and 6 g of PGME as a catalyst are added to the reaction vessel. The reaction was performed at 110 ° C. for 1 hour and at 115 ° C. for 8 hours. Then, it cooled to room temperature and obtained the copolymer solution (A-10) containing 38.9 weight% of acrylic resins. The weight average molecular weight (Mw) of the acrylic resin was 17500, and the acid value was 54 mgKOH / g.

[Production Example 11]
A separable flask equipped with a cooling tube was prepared as a reaction vessel. On the other hand, as a monomer composition in a monomer dropping tank, BzMI 15 g, AA 44.5 g, OPPE 20.5 g, 1 mol ethoxylated phenylphenol acrylate (trade name “A-LEN-10”, manufactured by Shin-Nakamura Chemical Co., Ltd., hereinafter A-LEN 20 g) (also referred to as −10), 2 g of PBO, 42 g of PGMEA, and 18 g of PGMEA were added and mixed with stirring. Further, 2 g of nDM, 18 g of PGMEA, and 8 g of PGME were added as a chain transfer agent solution into the chain transfer agent dropping tank, and mixed with stirring.
The reaction vessel was charged with 98 g of PGMEA and 42 g of PGME, purged with nitrogen, and then heated in an oil bath while stirring to raise the temperature of the reaction vessel to 90 ° C. After the temperature of the reaction vessel was stabilized at 90 ° C., the monomer composition and the chain transfer agent solution were added dropwise. The monomer composition and the chain transfer agent solution were added dropwise over 180 minutes while maintaining the temperature at 90 ° C. PBO 0.5g was added 30 minutes after the completion of the dropping. After another 30 minutes, the temperature of the reaction vessel was raised to 115 ° C. After maintaining at 115 ° C. for 1.5 hours, a gas introduction tube was attached to the separable flask, and bubbling of oxygen / nitrogen = 5/95 (v / v) mixed gas was started. Next, 69 g of GMA, 0.3 g of 6-tert-butyl-2,4-xylenol (trade name “Topanol”, manufactured by Tokyo Chemical Industry Co., Ltd.) as a polymerization inhibitor, and 0.5 g of DMBA, 16 g of PGMEA, and 6 g of PGME as a catalyst are added to the reaction vessel. The reaction was performed at 110 ° C. for 1 hour and at 115 ° C. for 8 hours. Then, it cooled to room temperature and obtained the copolymer solution (A-11) containing 39.1 weight% of acrylic resins. The weight average molecular weight (Mw) of the acrylic resin was 18100, and the acid value was 54 mgKOH / g.

[Production Example 12]
A separable flask equipped with a cooling tube was prepared as a reaction vessel. On the other hand, in the monomer dropping tank, as a monomer composition, 15 g of BzMI, 44.5 g of AA, 38.5 g of A-LEN-10, methoxypolyethylene glycol (400) acrylate (trade name “Light acrylate 130A”, manufactured by Kyoeisha Chemical Co., Ltd., 2 g of ethylene oxide moles n = 9, hereinafter also referred to as 130A), 2 g of PBO, 42 g of PGMEA, and 18 g of PGMEA were added and mixed with stirring. Further, 2 g of nDM, 18 g of PGMEA, and 8 g of PGME were added as a chain transfer agent solution into the chain transfer agent dropping tank, and mixed with stirring.
The reaction vessel was charged with 98 g of PGMEA and 42 g of PGME, purged with nitrogen, and then heated in an oil bath while stirring to raise the temperature of the reaction vessel to 90 ° C. After the temperature of the reaction vessel was stabilized at 90 ° C., the monomer composition and the chain transfer agent solution were added dropwise. The monomer composition and the chain transfer agent solution were added dropwise over 180 minutes while maintaining the temperature at 90 ° C. PBO 0.5g was added 30 minutes after the completion of the dropping. After another 30 minutes, the temperature of the reaction vessel was raised to 115 ° C. After maintaining at 115 ° C. for 1.5 hours, a gas introduction tube was attached to the separable flask, and bubbling of oxygen / nitrogen = 5/95 (v / v) mixed gas was started. Next, 69 g of GMA, 0.3 g of 6-tert-butyl-2,4-xylenol (trade name “Topanol”, manufactured by Tokyo Chemical Industry Co., Ltd.) as a polymerization inhibitor, and 0.5 g of DMBA, 16 g of PGMEA, and 6 g of PGME as a catalyst are added to the reaction vessel. The reaction was performed at 110 ° C. for 1 hour and at 115 ° C. for 8 hours. Then, it cooled to room temperature and obtained the copolymer solution (A-12) containing 39.4 weight% of acrylic resins. The weight average molecular weight (Mw) of the acrylic resin was 17500, and the acid value was 55 mgKOH / g.

[Production Example 13]
A separable flask equipped with a cooling tube was prepared as a reaction vessel. On the other hand, 15 g of BzMI, 44.5 g of AA, 38.5 g of A-LEN-10, methoxypolyethylene glycol (550) acrylate (trade name “CD550”, manufactured by Sakai Kogyo Co., Ltd., ethylene oxide) as a monomer composition in the monomer dropping tank 2 g of mole number n = 12 to 13 (hereinafter also referred to as CD550), 2 g of PBO, 42 g of PGMEA, and 18 g of PGMEA were added and mixed with stirring. Further, 2 g of nDM, 18 g of PGMEA, and 8 g of PGME were added as a chain transfer agent solution into the chain transfer agent dropping tank, and mixed with stirring.
The reaction vessel was charged with 98 g of PGMEA and 42 g of PGME, purged with nitrogen, and then heated in an oil bath while stirring to raise the temperature of the reaction vessel to 90 ° C. After the temperature of the reaction vessel was stabilized at 90 ° C., the monomer composition and the chain transfer agent solution were added dropwise. The monomer composition and the chain transfer agent solution were added dropwise over 180 minutes while maintaining the temperature at 90 ° C. PBO 0.5g was added 30 minutes after the completion of the dropping. After another 30 minutes, the temperature of the reaction vessel was raised to 115 ° C. After maintaining at 115 ° C. for 1.5 hours, a gas introduction tube was attached to the separable flask, and bubbling of oxygen / nitrogen = 5/95 (v / v) mixed gas was started. Next, 69 g of GMA, 0.3 g of 6-tert-butyl-2,4-xylenol (trade name “Topanol”, manufactured by Tokyo Chemical Industry Co., Ltd.) as a polymerization inhibitor, and 0.5 g of DMBA, 16 g of PGMEA, and 6 g of PGME as a catalyst are added to the reaction vessel. The reaction was performed at 110 ° C. for 1 hour and at 115 ° C. for 8 hours. Then, it cooled to room temperature and obtained the copolymer solution (A-13) containing 39.0 weight% of acrylic resins. The weight average molecular weight (Mw) of the acrylic resin was 18000, and the acid value was 53 mgKOH / g.

[Production Example 14]
A separable flask equipped with a cooling tube was prepared as a reaction vessel. On the other hand, 15 g of BzMI, 44.5 g of AA, 20.5 g of OPPE, 20 g of dicyclopentanyl acrylate (DCPA), 2 g of PBO, 42 g of PGMEA and 18 g of PGME were added to the monomer dropping tank and mixed with stirring. Further, 2 g of nDM, 18 g of PGMEA, and 8 g of PGME were added as a chain transfer agent solution into the chain transfer agent dropping tank, and mixed with stirring.
The reaction vessel was charged with 98 g of PGMEA and 42 g of PGME, purged with nitrogen, and then heated in an oil bath while stirring to raise the temperature of the reaction vessel to 90 ° C. After the temperature of the reaction vessel was stabilized at 90 ° C., the monomer composition and the chain transfer agent solution were added dropwise. The monomer composition and the chain transfer agent solution were added dropwise over 180 minutes while maintaining the temperature at 90 ° C. PBO 0.5g was added 30 minutes after the completion of the dropping. After another 30 minutes, the temperature of the reaction vessel was raised to 115 ° C. After maintaining at 115 ° C. for 1.5 hours, a gas introduction tube was attached to the separable flask, and bubbling of oxygen / nitrogen = 5/95 (v / v) mixed gas was started. Next, 69 g of GMA, 0.3 g of 6-tert-butyl-2,4-xylenol (trade name “Topanol”, manufactured by Tokyo Chemical Industry Co., Ltd.) as a polymerization inhibitor, and 0.5 g of DMBA, 16 g of PGMEA, and 6 g of PGME as a catalyst are added to the reaction vessel. The reaction was performed at 110 ° C. for 1 hour and at 115 ° C. for 8 hours. Then, it cooled to room temperature and obtained the copolymer solution (A-14) containing 39.1 weight% of acrylic resins. The weight average molecular weight (Mw) of the acrylic resin was 17800, and the acid value was 56 mgKOH / g.

[Production Example 15]
A separable flask equipped with a cooling tube was prepared as a reaction vessel. On the other hand, 15 g of BzMI, 44.5 g of AA, 40.5 g of A-LEN-10, 2 g of PBO, 42 g of PGMEA and 18 g of PGMEA were added as a monomer composition into the monomer dropping tank, and mixed with stirring. Further, 2 g of nDM, 18 g of PGMEA, and 8 g of PGME were added as a chain transfer agent solution into the chain transfer agent dropping tank, and mixed with stirring.
The reaction vessel was charged with 98 g of PGMEA and 42 g of PGME, purged with nitrogen, and then heated in an oil bath while stirring to raise the temperature of the reaction vessel to 90 ° C. After the temperature of the reaction vessel was stabilized at 90 ° C., the monomer composition and the chain transfer agent solution were added dropwise. The monomer composition and the chain transfer agent solution were added dropwise over 180 minutes while maintaining the temperature at 90 ° C. PBO 0.5g was added 30 minutes after the completion of the dropping. After another 30 minutes, the temperature of the reaction vessel was raised to 115 ° C. After maintaining at 115 ° C. for 1.5 hours, a gas introduction tube was attached to the separable flask, and bubbling of oxygen / nitrogen = 5/95 (v / v) mixed gas was started. Next, 69 g of GMA, 0.3 g of 6-tert-butyl-2,4-xylenol (trade name “Topanol”, manufactured by Tokyo Chemical Industry Co., Ltd.) as a polymerization inhibitor, and 0.5 g of DMBA, 16 g of PGMEA, and 6 g of PGME as a catalyst are added to the reaction vessel. The reaction was performed at 110 ° C. for 1 hour and at 115 ° C. for 8 hours. Then, it cooled to room temperature and obtained the copolymer solution (A-15) containing 39.4 weight% of acrylic resins. The weight average molecular weight (Mw) of the acrylic resin was 17400, and the acid value was 54 mgKOH / g.

[Production Example 16]
A separable flask equipped with a cooling tube was prepared as a reaction vessel. On the other hand, in the monomer dropping tank, BzMI 15 g, AA 44.5 g, phenoxydiethylene glycol acrylate (trade name “light acrylate P2HA”, manufactured by Kyoeisha Chemical Co., hereinafter also referred to as P2HA), 40.5 g, PBO 2 g, PGMEA 42 g, and PGME 18 g Was stirred and mixed. Further, 2 g of nDM, 18 g of PGMEA, and 8 g of PGME were added as a chain transfer agent solution into the chain transfer agent dropping tank, and mixed with stirring.
The reaction vessel was charged with 98 g of PGMEA and 42 g of PGME, purged with nitrogen, and then heated in an oil bath while stirring to raise the temperature of the reaction vessel to 90 ° C. After the temperature of the reaction vessel was stabilized at 90 ° C., the monomer composition and the chain transfer agent solution were added dropwise. The monomer composition and the chain transfer agent solution were added dropwise over 180 minutes while maintaining the temperature at 90 ° C. PBO 0.5g was added 30 minutes after the completion of the dropping. After another 30 minutes, the temperature of the reaction vessel was raised to 115 ° C. After maintaining at 115 ° C. for 1.5 hours, a gas introduction tube was attached to the separable flask, and bubbling of oxygen / nitrogen = 5/95 (v / v) mixed gas was started. Next, 69 g of GMA, 0.3 g of 6-tert-butyl-2,4-xylenol (trade name “Topanol”, manufactured by Tokyo Chemical Industry Co., Ltd.) as a polymerization inhibitor, and 0.5 g of DMBA, 16 g of PGMEA, and 6 g of PGME as a catalyst are added to the reaction vessel. The reaction was performed at 110 ° C. for 1 hour and at 115 ° C. for 8 hours. Then, it cooled to room temperature and obtained the copolymer solution (A-16) containing 38.8 weight% of acrylic resins. The weight average molecular weight (Mw) of the acrylic resin was 18100, and the acid value was 56 mgKOH / g.

[Production Example 17]
A separable flask equipped with a cooling tube was prepared as a reaction vessel. On the other hand, as a monomer composition, 15 g of BzMI, 44.5 g of AA, 40.5 g of DCPA, 2 g of PBO, 42 g of PGMEA and 18 g of PGME were added to the monomer dropping tank and mixed. Further, 2 g of nDM, 18 g of PGMEA, and 8 g of PGME were added as a chain transfer agent solution into the chain transfer agent dropping tank, and mixed with stirring.
The reaction vessel was charged with 98 g of PGMEA and 42 g of PGME, purged with nitrogen, and then heated in an oil bath while stirring to raise the temperature of the reaction vessel to 90 ° C. After the temperature of the reaction vessel was stabilized at 90 ° C., the monomer composition and the chain transfer agent solution were added dropwise. The monomer composition and the chain transfer agent solution were added dropwise over 180 minutes while maintaining the temperature at 90 ° C. PBO 0.5g was added 30 minutes after the completion of the dropping. After another 30 minutes, the temperature of the reaction vessel was raised to 115 ° C. After maintaining at 115 ° C. for 1.5 hours, a gas introduction tube was attached to the separable flask, and bubbling of oxygen / nitrogen = 5/95 (v / v) mixed gas was started. Next, 69 g of GMA, 0.3 g of 6-tert-butyl-2,4-xylenol (trade name “Topanol”, manufactured by Tokyo Chemical Industry Co., Ltd.) as a polymerization inhibitor, and 0.5 g of DMBA, 16 g of PGMEA, and 6 g of PGME as a catalyst are added to the reaction vessel. The reaction was performed at 110 ° C. for 1 hour and at 115 ° C. for 8 hours. Then, it cooled to room temperature and obtained the copolymer solution (A-17) containing 39.6 weight% of acrylic resins. The weight average molecular weight (Mw) of the acrylic resin was 18500, and the acid value was 55 mgKOH / g.

[Example 1]
89 g of the copolymer solution (A-1) (that is, 35 g of acrylic resin), 65 g of tripentaerythritol octaacrylate (trade name “Biscoat # 802”, manufactured by Osaka Organic Chemical Co., Ltd.) as a polyfunctional monomer, and a wavelength of 290 nm to 2-Methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one (trade name “IRGACURE” as a photopolymerization initiator (first photopolymerization initiator) having a maximum absorption wavelength at 380 nm (Registered trademark) 907 ", manufactured by BASF Japan Ltd.) 1.75 g, 2-hydroxy-1- {4- [as a photopolymerization initiator (second photopolymerization initiator) having a maximum absorption wavelength at a wavelength of 230 nm to 290 nm 4- (2-Hydroxy-2-methyl-propionyl) -benzyl] -phenyl} -2-methyl-propan-1-one (trade name) IRGACURE (registered trademark) 127 ”(manufactured by BASF Japan, Inc.) 0.25 g, 2- (2-hydroxy-4-octoxyphenyl) -2H-benzotriazole (trade name“ SEESORB707 ”, Sipro Kasei Co., Ltd.) as UV absorber PGMEA was added to 0.5 g of a mixture (hereinafter referred to as “SB707”) so that the solid concentration was 35% by weight, and the mixture was filtered with a filter having a pore diameter of 0.5 μm to prepare a photosensitive resin composition for photospacers.
The photosensitive resin composition was applied onto a 10 cm square glass substrate with a spin coater and dried in an oven at 80 ° C. for 3 minutes. After drying, the strength (50 mJ / cm ² ) by a UV aligner (trade name “TME-150RNS”, manufactured by TOPCON) with a photomask placed at a distance of 100 μm from the coating film and equipped with a 2.0 kW super high pressure mercury lamp. Ultraviolet rays were irradiated at 365 nm illuminance conversion). After UV irradiation, 0.05% potassium hydroxide aqueous solution is sprayed on the coating film with a spin developing machine for 40 seconds to dissolve and remove the unexposed area, and the remaining exposed area is washed with pure water for 10 seconds. Development was performed to form a cylindrical photospacer. The presence or absence of a development residue was confirmed (evaluation (4)), and the obtained photospacer was subjected to the evaluations (5) to (10). The results are shown in Table 2.

[Examples 2 to 27]
Except that the composition of the photosensitive resin composition was changed to the composition shown in Table 2, a photospacer was formed in the same manner as in Example 1 and subjected to the same evaluation as in Example 1. The results are shown in Table 2.
In Table 2, dipentaerythritol hexaacrylate (manufactured by Kyoeisha Chemical Co., Ltd.) is represented as “DPHA”, and pentaerythritol tetraacrylate (manufactured by Kyoeisha Chemical Co., Ltd.) is represented as “PETA”.
Regarding the UV absorber, in Table 2, the trade name “Tinuvin 479” manufactured by BASF Japan Ltd. is expressed as “T479”.
Regarding the second photopolymerization initiator, in Table 2, the trade name “IRGACURE (registered trademark) 2959” manufactured by BASF Japan is represented as “I2959” and “IRGACURE (registered trademark) 184” as “I184”.

[Comparative Examples 1-5]
A photospacer was formed in the same manner as in Example 1 except that the composition of the photosensitive resin composition was changed to the composition shown in Table 3, and was subjected to the same evaluation as in Example 1. The results are shown in Table 3.
Regarding the photopolymerization initiator, in Table 3, the trade name “IRGACURE (registered trademark) 651” manufactured by BASF Japan is represented as “I651” and “IRGACURE (registered trademark) 819” as “I851”. “I651” and “I819” do not have a maximum absorption wavelength at wavelengths of 230 nm to 290 nm.

  As is clear from Tables 2 and 3, the photospacer of the present invention is excellent in the balance between the diameter and the mechanical properties, and is excellent in the compression rate, the elastic recovery rate, and the breaking strength.

  The photospacer of the present invention can be suitably used as a liquid crystal cell spacer.

  10, 20 Photo spacer

Claims (5)

An alkali-soluble resin;
A polyfunctional monomer ;
A first photopolymerization initiator having a maximum absorption wavelength at a wavelength of 290 nm to 380 nm;
A columnar photospacer formed from a photosensitive resin composition comprising a second photopolymerization initiator having a maximum absorption wavelength at a wavelength of 230 nm to 290 nm ,
The alkali-soluble resin has a repeating unit having a ring structure in the main chain and a repeating unit having a carbon double bond in the side chain, and the repeating unit having a ring structure in the main chain is represented by formulas (1) to ( 7) at least one selected from repeating units represented by
The horizontal cross-sectional area A1 of the portion away from the lower part of the photospacer in the height direction (height of photospacer × 1/2) is equal to the height direction from the lower part of the photospacer (height of photospacer × 1 / 4) The horizontal cross-sectional area A2 of the distant part is less than,
The diameter at the bottom of the photospacer is 8 μm or less,
Photo spacer:

In formulas (4) to (7), R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are each independently a hydrogen atom or a linear or branched group having 1 to 30 carbon atoms. It is an alkyl group.   The photospacer according to claim 1, wherein the breaking strength is 160 mN to 300 mN. The photospacer according to claim 1 or 2 , wherein the polyfunctional monomer has a pentaerythritol skeleton. The photospacer according to any one of claims 1 to 3 , wherein a ratio (A2 / A1) of the horizontal sectional area A1 to the horizontal sectional area A2 is 1 to 1.3. Claims 1 comprises a photo spacer according to any one of 4, a liquid crystal display.

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