WO2023027010A1 - Photosensitive resin composition, cured product, and image display device - Google Patents

Abstract

The present invention provides: a photosensitive resin composition that makes it possible to form a cured product (for example, a photospacer) offering both a high rate of elastic recovery and excellent flexibility; a cured product obtained from the photosensitive resin composition; and an image display device comprising the cured product. The photosensitive resin composition of the present invention contains: an alkali-soluble resin (A) having a double bond equivalent of 200 g/mol or less; a monomer group (B) that includes a first crosslinkable (meth)acrylate monomer (B1) having six or more crosslinkable functional groups, at least one of the crosslinkable functional groups being a hydrogen bond-type crosslinkable functional group, and a second crosslinkable (meth)acrylate monomer (B2) that has six or more crosslinkable functional groups, the number of hydrogen bond-type crosslinkable functional groups among the crosslinkable functional groups being smaller than the number of hydrogen bond-type crosslinkable functional groups that the first crosslinkable (meth)acrylate monomer (B1) has, the acid value of the monomer group (B) being 1-20 mgKOH/g; and a photopolymerization initiator (C).

Description

Photosensitive resin composition, cured product, and image display device

The present invention relates to a photosensitive resin composition, a cured product obtained from the photosensitive resin composition, and an image display device containing the cured product.

In the liquid crystal display device, a photospacer is used to maintain the thickness of the liquid crystal layer sandwiched between the substrate on the color filter side and the substrate on the thin film transistor (TFT) side.

The photospacer must have a high elastic recovery rate in order to suppress variations in the cell gap due to stress during use of the liquid crystal display device.

For example, in Patent Document 1, the object is to provide an active energy ray-curable resin composition that gives a cured product exhibiting an excellent elastic recovery rate against deformation due to external force.
a monomer unit (1) with a branched side chain having 2-3 ends each terminating in a radically polymerizable substituent and 2 having an end terminating in a carboxy group and an end terminating in a radically polymerizable substituent comprising as building blocks a monomer unit (2) with a two-branched side chain, or additionally a monomer unit (3) with a single terminal side chain ending with a radically polymerizable substituent A photosensitive resin composition has been proposed which comprises a polymerizable (meth)acrylic polymer (A), a polyfunctional (meth)acrylate monomer component (B), and a photopolymerization initiator (C).

In addition, since the liquid crystal display element is easily deformed when pressure or impact is applied from the outside, the deformation may crack the photospacer, and the deformed photospacer may damage (scrape) the alignment film on the TFT side substrate. Therefore, there is a demand for a highly flexible photospacer that is less likely to be damaged and less likely to damage the alignment film.

For example, in Patent Document 2, when used as a spacer, it is a photospacer with a high restoration rate in which plastic deformation is suppressed, but a photosensitive resin that is extremely suppressed from scraping the liquid crystal alignment film provided on the opposing substrate. For the purpose of providing a composition,
A photosensitive resin composition containing an alkali-soluble resin, a photopolymerization initiator and a polymerizable compound, wherein the urethane equivalent of the solid content of the resin composition is 1000 to 50000 g / mol, and an ethylenically unsaturated A photosensitive resin composition having a saturated group equivalent weight of 100 to 155 g/mol has been proposed.

Further, in Patent Document 3, with the object of providing a negative photosensitive resin composition capable of forming a photospacer having a high elastic recovery rate and excellent flexibility,
(A) an alkali-soluble resin, (B) a photoradical polymerization initiator and (C) a photopolymerizable monomer, and the content of the (A) alkali-soluble resin is the same as the (A) alkali-soluble resin and the (C) ) 3 parts by weight or more and 45 parts by weight or less with respect to a total of 100 parts by weight with the photopolymerizable monomer, and the (C) photopolymerizable monomer contains a di(meth)acrylate having a poly(oxyalkylene) group , a negative photosensitive resin composition has been proposed.

International Publication No. 2018/169036 International Publication No. 2019/216107 JP 2020-71483 A

Patent Documents 2 and 3 describe a photosensitive resin composition capable of forming a photospacer having a high elastic recovery rate and excellent flexibility. There has been a demand for development of a photosensitive resin composition capable of forming a photospacer having both excellent properties.

The present invention provides a photosensitive resin composition capable of forming a cured product (e.g., photospacer) having both a high elastic recovery rate and excellent flexibility, a cured product obtained from the photosensitive resin composition, and It aims at providing the image display apparatus containing the said hardened|cured material.

As a result of intensive studies aimed at solving the above problems, the present inventors have found that the above objects can be achieved by using the photosensitive resin composition shown below, and have completed the present invention.

The present invention provides an alkali-soluble resin (A) having a double bond equivalent of 200 g/mol or less,
A first crosslinkable (meth)acrylate monomer (B1) having six or more crosslinkable functional groups, at least one of which is a hydrogen-bonding crosslinkable functional group, and six or more crosslinkable It has a functional group, and the number of hydrogen-bonding crosslinkable functional groups in the crosslinkable functional group is greater than the number of the hydrogen-bonding crosslinkable functional groups in the first crosslinkable (meth)acrylate monomer (B1). a monomer group (B) containing a small amount of the second crosslinkable (meth)acrylate monomer (B2) and having an acid value of 1 to 20 mgKOH/g;
The present invention relates to a photosensitive resin composition containing a photopolymerization initiator (C).

The monomer group (B) preferably has a hydroxyl value of 15 to 70 mgKOH/g.

The second crosslinkable (meth)acrylate monomer (B2) preferably does not have a hydrogen-bonding crosslinkable functional group.

The photosensitive resin composition of the present invention preferably contains 80 to 200 parts by mass of the monomer group (B) with respect to 100 parts by mass of the alkali-soluble resin (A).

The mass ratio (B1:B2) between the first crosslinkable (meth)acrylate monomer (B1) and the second crosslinkable (meth)acrylate monomer (B2) is preferably 1:10 to 10:1. .

The cured product of the present invention is obtained from the photosensitive resin composition. The cured product is preferably a photospacer, a partition wall material, a lens material, an interlayer insulating film material, a protective film material, an optical waveguide material, or a flattening film material.

The present invention also relates to an image display device containing the cured product.

The photosensitive resin composition of the present invention includes, together with an alkali-soluble resin (A) having a double bond equivalent of 200 g/mol or less, a first crosslinkable (meth)acrylate monomer (B1) and a second It is characterized by containing two types of cross-linkable monomers, a di-crosslinkable (meth)acrylate monomer (B2), and by using these three components, a cured product that achieves both a high elastic recovery rate and excellent flexibility. can be formed. For example, when the cured product of the present invention is a photospacer, since the photospacer of the present invention has a high elastic recovery rate, it is possible to effectively suppress fluctuations in the cell gap due to stress during use of the liquid crystal display device. can. In addition, the photospacer of the present invention has excellent flexibility, so that it is hard to break and hard to damage the alignment film of the substrate on the TFT side (the alignment film is hard to scrape). Furthermore, when the cured product of the photosensitive resin composition of the present invention is used as a resist material, the solubility of the uncured portion in the developer (hereinafter simply referred to as the solubility in the developer) is excellent. In addition, it is possible to produce a cured product (for example, a photospacer) with small unevenness in height (scan unevenness, lens unevenness).

In the present invention, "(meth)acrylic" means acrylic and/or methacrylic. "(Meth)acrylate" and the like have the same meaning. In the present invention, the term "crosslinkable functional group" means a functional group that forms a crosslinked structure by reacting with other functional groups or interacting with other atoms. In addition, the "hydrogen-bonding crosslinkable functional group" is a type of crosslinkable functional group, and other monomers (including not only heterogeneous monomers but also monomers of the same type) or alkali-soluble resins (A) in close proximity It means a structure that can be hydrogen-bonded and a functional group that forms a cross-linked structure by interacting with the hydrogen-bond. The structure capable of hydrogen bonding is not particularly limited as long as it is capable of hydrogen bonding with other monomers or the structure of the alkali-soluble resin (A), and may be the crosslinkable functional group itself.

The double bond equivalent in the present invention refers to the number of grams of the object per 1 mol of the group having a double bond, and the double bond equivalent = (amount of object (g) / object containing double bond number of groups (mol)). Although the group having a double bond is not particularly limited, it is typically an ethylenically unsaturated group, and examples of the ethylenically unsaturated group include an acryloyl group and a methacryloyl group.

The acid value in the present invention represents the mass (mg) of potassium hydroxide required to neutralize the acidic component contained in 1 g of the object, and the molecular weight based on the structure of the object and the number of functional groups per molecule. It is a theoretical value calculated from (the number of acid groups). Specifically, the acid value of the object is a value obtained by [number of moles of acid groups of the object (mmol)]×[56.11/amount of object (g)]. The hydroxyl value in the present invention represents the mass (mg) of potassium hydroxide required to neutralize the acetic acid bound to the hydroxyl group after acetylating 1 g of the object, and the molecular weight and It is a theoretical value calculated from the number of functional groups (number of hydroxyl groups) per molecule. Specifically, the hydroxyl value of the object is a value obtained by [number of moles of hydroxyl groups of the object (mmol)]×[56.11/amount of object (g)]. In addition, alkali-soluble resin (A) and monomer group (B) are mentioned as a target object in an acid value and a hydroxyl value.

Targets for the double bond equivalent, acid value, and hydroxyl value include the alkali-soluble resin (A) and the monomer group (B), and the structure of these targets and the content in the photosensitive resin composition The amount and the like may be specified by analyzing the photosensitive resin composition by a known method, and specified from the structure and ratio of the raw material (object) used when producing the photosensitive resin composition. Also good.

The photosensitive resin composition of the present invention contains an alkali-soluble resin (A), a monomer group (B), and a photopolymerization initiator (C). The alkali-soluble resin (A) has a double bond equivalent of 200 g/mol or less. The monomer group (B) contains a first crosslinkable (meth)acrylate monomer (B1) and a second crosslinkable (meth)acrylate monomer (B2), and has an acid value of 1 to 20 mgKOH/g. The first crosslinkable (meth)acrylate monomer (B1) has six or more crosslinkable functional groups, and at least one of the crosslinkable functional groups is a hydrogen-bonding crosslinkable functional group. The second crosslinkable (meth)acrylate monomer (B2) has 6 or more crosslinkable functional groups, and the number of hydrogen-bonding crosslinkable functional groups in the crosslinkable functional groups is the first crosslinkable (meth) It is less than the number of hydrogen-bonding crosslinkable functional groups possessed by the acrylate monomer (B1).

Although not bound by theory, the reason why it is possible to form a cured product having both a high elastic recovery rate and excellent flexibility by using the photosensitive resin composition of the present invention is speculated as follows. When a monomer having a relatively large number of polymerizable functional groups is used in a photosensitive resin composition, it is not a structure in which the main chain is formed by serially bonding (polymerizing) the monomers, but one monomer unit has a plurality of A crosslinked structure is formed by combining with other monomers. In such a case, the present inventor found that the crosslinkable functional groups within the monomer unit are likely to bond with each other, resulting in an undesirable effect on the elastic recovery rate and flexibility of the resulting cured film. . Therefore, the present inventor uses two types of (meth)acrylate monomers, at least one (meth)acrylate monomer has a hydrogen-bonding crosslinkable functional group, and the other (meth)acrylate monomer has a hydrogen bond By making the number of type crosslinkable functional groups smaller than the number of hydrogen bond type crosslinkable functional groups of one (meth) acrylate monomer, it is possible to prevent the crosslinkable functional groups from easily bonding to each other within the monomer unit, It was found that the formation of bonds between different monomer units (including not only the formation of bonds between different monomers but also the formation of bonds between monomers of the same type) and the bonding between the monomers and the alkali-soluble resin (A) can be promoted. Furthermore, since at least one (meth)acrylate monomer contains a hydrogen-bonding crosslinkable functional group, all the crosslinkable functional groups can be hydrogen-bonded crosslinkable instead of forming relatively strong covalent bonds. At least part of the functional groups cross-link with hydrogen-bondable structures possessed by other adjacent monomers through relatively weak hydrogen bonds. In addition, when the side chain of the alkali-soluble resin (A) has a structure capable of hydrogen bonding with a hydrogen-bonding crosslinkable functional group, this structure and the hydrogen-bonding crosslinkable functional group of the monomer are compared by hydrogen bonding. Cross-linking with hydrogen bonds with weak physical bonding strength. Thus, in the present invention, both hydrogen bonds with relatively weak bonding strength and covalent bonds with relatively strong bonding strength coexist in the cured product, so that the rigidity and elasticity of the cured product are precisely controlled. it is conceivable that. As a result, it is presumed that a network structure that achieves both a high elastic recovery rate and excellent flexibility is formed when the photosensitive resin composition is cured.

[Alkali-soluble resin (A)]
The alkali-soluble resin (A) is not particularly limited as long as it has a double bond equivalent of 200 g/mol or less. In the present invention, the elastic recovery rate can be improved by using an alkali-soluble resin having a double bond equivalent of 200 g/mol or less, which has a relatively low double bond equivalent. The double bond equivalent of the alkali-soluble resin (A) is preferably 160 g/mol or less.

Monomers forming the alkali-soluble resin (A) are not particularly limited, for example, (meth) acrylic acid, 2-(meth) acryloyloxyethyl succinic acid, maleic acid, and carboxy group-containing monomers such as itaconic acid; maleic anhydride Acids and carboxylic anhydride group-containing monomers such as itaconic anhydride; methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, benzyl (meth) acrylate, lauryl (meth) Alkyl (meth)acrylates such as acrylates, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, ethoxyethyl (meth)acrylate, and glycidyl (meth)acrylate; cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, and Alicyclic (meth)acrylates such as dicyclopentenyl (meth)acrylate and the like are included. Also, styrene, cyclohexylmaleimide, phenylmaleimide, methylmaleimide, ethylmaleimide, n-butylmaleimide, laurylmaleimide, silicone-containing monomers, and the like may be used as copolymerizable monomers. These monomers may be used alone or in combination of two or more.

The alkali-soluble resin (A) may have an acid group in its side chain in order to impart alkali developability to the photosensitive resin composition. The method for introducing an acid group into the side chain of the alkali-soluble resin (A) is not particularly limited, and known methods can be employed. A method of adding an acid anhydride to a hydroxyl group generated by adding an epoxy group-containing compound such as glycidyl (meth)acrylate to a polymer obtained by copolymerizing a carboxy group-containing monomer such as meth)acrylic acid, and glycidyl (meth)acrylic acid. ) A method of adding an acid anhydride to the hydroxyl group generated by adding a carboxy group-containing compound such as (meth)acrylic acid to a polymer obtained by copolymerizing an epoxy group-containing monomer such as acrylate.

Also, an ethylenically unsaturated group may be introduced into the side chain of the alkali-soluble resin (A). As a method for introducing an ethylenically unsaturated group into the side chain of the alkali-soluble resin (A), for example, a polymer obtained by copolymerizing an epoxy group-containing monomer such as glycidyl (meth)acrylate is added with (meth)acrylic acid or the like. A method of adding a compound having an ethylenically unsaturated group and a carboxyl group, a polymer obtained by copolymerizing a carboxyl group-containing monomer such as (meth)acrylic acid, an ethylenically unsaturated group such as glycidyl (meth)acrylate, and an epoxy A method of adding a compound having a group, and an ethylenically unsaturated group such as (meth) acryloyloxyethyl isocyanate and an isocyanate group to a polymer obtained by copolymerizing a hydroxy group-containing monomer such as hydroxyethyl (meth) acrylate. and a method of adding a compound having the

At least one of the main chain and side chain of the alkali-soluble resin (A) may contain a structure capable of hydrogen bonding with the hydrogen-bonding crosslinkable functional group of the (meth)acrylate monomer (B1) or (B2). This is because, as described above, both hydrogen bonds with relatively weak bonding strength and covalent bonds with relatively strong bonding strength coexist in the cured product, so that the rigidity and elasticity of the cured product can be precisely controlled. Structures capable of forming hydrogen bonds with hydrogen-bonding crosslinkable functional groups in the main chain and side chains of the alkali-soluble resin (A) include, for example, -COOH, -OH, and -NH-. -COOH and -OH are preferred from the viewpoint of easy maintenance. Moreover, from the viewpoint of facilitating the formation of hydrogen bonds, it is preferable that the side chains of the alkali-soluble resin (A) contain structures capable of hydrogen bonding.

The weight average molecular weight (Mw) of the alkali-soluble resin (A) is not particularly limited, but when using the photosensitive resin composition as a resist material such as a photospacer, from the viewpoint of obtaining good exposure sensitivity and good developability (hereinafter , simply from the viewpoint of improving good exposure sensitivity and heat resistance), it is preferably 5,000 to 100,000, more preferably 10,000 to 30,000. The weight average molecular weight can be determined by gel permeation chromatography (GPC) in accordance with JIS K 7252-1:2016, and is a value converted from standard polystyrene.

The double bond equivalent of the alkali-soluble resin (A) is 200 g/mol or less, preferably 180 g/mol or less, more preferably 170 g, from the viewpoint of improving good exposure sensitivity and heat resistance of the photosensitive resin composition. /mol or less, more preferably 160 g/mol or less.

The acid value of the alkali-soluble resin (A) is not particularly limited, but from the viewpoint of imparting good developability to the photosensitive resin composition, it is preferably 10 to 200 mgKOH/g, more preferably 15 to 150 mgKOH/g. , more preferably 20 to 100 mgKOH/g, particularly preferably 25 to 75 mgKOH/g, most preferably 30 to 50 mgKOH/g.

The polymerizable (meth)acrylic polymer (A) described in International Publication No. 2018/169036 may be used as the alkali-soluble resin (A).

[Monomer group (B)]
The monomer group (B) is a monomer group containing at least both the first crosslinkable (meth)acrylate monomer (B1) and the second crosslinkable (meth)acrylate monomer (B2). When the monomer group (B) contains three or more crosslinkable (meth)acrylate monomers, and all of them contain hydrogen-bonding crosslinkable functional groups, the one with the least number of hydrogen-bonding crosslinkable functional groups is selected. This is referred to as a second crosslinkable (meth)acrylate monomer (B2). Further, the monomer group (B) contains three or more crosslinkable (meth)acrylate monomers, at least one of which is a crosslinkable (meth)acrylate monomer having no hydrogen-bonding crosslinkable functional group. In this case, a crosslinkable (meth)acrylate monomer having no hydrogen-bonding crosslinkable functional group is used as the second crosslinkable (meth)acrylate monomer (B2).

The photosensitive resin composition of the present invention may have, for example, the following aspects (1) to (5).
(1) A mode containing a plurality of types of first crosslinkable (meth)acrylate monomers (B1) and a plurality of types of second crosslinkable (meth)acrylate monomers (B2).
(2) A mode containing a plurality of types of first crosslinkable (meth)acrylate monomers (B1) and a single type of second crosslinkable (meth)acrylate monomer (B2).
(3) A mode containing a single type of first crosslinkable (meth)acrylate monomer (B1) and a plurality of types of second crosslinkable (meth)acrylate monomers (B2).
(4) A mode containing a single type of first crosslinkable (meth)acrylate monomer (B1) and a single type of second crosslinkable (meth)acrylate monomer (B2).
(5) In any one of the above (1) to (4), an embodiment further containing another monomer.

In the above aspects (1) and (2), the plurality of types of monomers corresponding to the first crosslinkable (meth)acrylate monomer (B1) may have the same or different numbers of crosslinkable functional groups, The number of hydrogen-bonding crosslinkable functional groups may be the same or different. In addition, the number of hydrogen-bonding crosslinkable functional groups in the second crosslinkable (meth)acrylate monomer (B2) is the largest among the plurality of types of monomers corresponding to the first crosslinkable (meth)acrylate monomer (B1). The number of hydrogen-bonding crosslinkable functional groups is less than the one with less. In the above aspect (1), the plurality of types of monomers corresponding to the second crosslinkable (meth)acrylate monomer (B2) may have the same or different numbers of crosslinkable functional groups, but hydrogen All the monomers corresponding to the second crosslinkable (meth)acrylate monomer (B2) have the same number of bonded crosslinkable functional groups. Also in the above aspect (3), the number of hydrogen-bonding crosslinkable functional groups is the same for all monomers corresponding to the second crosslinkable (meth)acrylate monomer (B2).

The monomer group (B) has an acid value of 1 to 20 mgKOH/g from the viewpoint of promoting the formation of a crosslinked structure between different monomer units and the formation of a crosslinked structure between the monomer and the alkali-soluble resin (A). Yes, preferably 3 to 15 mgKOH/g, more preferably 6 to 12 mgKOH/g. The monomer group (B) contains at least a first crosslinkable (meth)acrylate monomer (B1) and a second crosslinkable (meth)acrylate monomer (B2), and optionally other monomers. Therefore, the acid value of the monomer group (B) is obtained by calculating the acid value of each monomer, multiplying the acid value of each monomer by the mass ratio of that monomer in the monomer group (B), and calculating these values. shall be the sum of The same applies to each acid value when a plurality of types of first crosslinkable (meth)acrylate monomers (B1) are included and when a plurality of types of second crosslinkable (meth)acrylate monomers (B2) are included. These points also apply to the hydroxyl value described later.

The monomer group (B) has the viewpoint of promoting the formation of a crosslinked structure with the different monomers described above and the formation of a crosslinked structure between the monomer and the alkali-soluble resin (A). From the viewpoint of being able to maintain a high elastic recovery rate and excellent flexibility even when repeatedly pressed (hereinafter referred to as having high durability), adhesion to the application target when applying the photosensitive resin composition to a substrate etc. From the viewpoint of improving the property and the viewpoint of excellent solubility in a developer, the hydroxyl value is preferably 15 to 70 mgKOH/g, more preferably 20 to 60 mgKOH/g, and still more preferably 25 to 55 mgKOH. /g.

<First crosslinkable (meth)acrylate monomer (B1)>
The first crosslinkable (meth)acrylate monomer (B1) has six or more crosslinkable functional groups, and at least one of the crosslinkable functional groups is a hydrogen-bonding crosslinkable functional group. Also, at least one crosslinkable functional group is an acryloyl group or a methacryloyl group.

The crosslinkable functional group is not particularly limited, and examples include acryloyl groups, methacryloyl groups, vinyl groups, carboxy groups, hydroxyl groups, thio groups, amino groups, epoxy groups, and isocyanate groups. Two or more of these crosslinkable functional groups may be contained. Acryloyl and methacryloyl groups contain a vinyl structure in their structure, but are recognized as different from acryloyl and methacryloyl groups and vinyl groups. Similarly, carboxy groups include --OH, but carboxy groups and hydroxyl groups are recognized as different. The first crosslinkable (meth)acrylate monomer (B1) may have a functional group other than the crosslinkable functional group. These points are the same for the crosslinkable functional group of the second crosslinkable (meth)acrylate monomer (B2) described later.

The hydrogen-bonding crosslinkable functional group is not particularly limited as long as it is a functional group capable of hydrogen-bonding with other monomer units, and examples include a carboxy group, a hydroxyl group, an amino group, and the like. One type of these hydrogen-bonding crosslinkable functional groups may be contained, or two or more types may be contained. The hydrogen-bonding crosslinkable functional group preferably has at least one of a carboxy group and a hydroxyl group, and more preferably has one of a carboxy group and a hydroxyl group and does not have the other, from the viewpoint of easily maintaining a hydrogen bond. .

The first crosslinkable (meth)acrylate monomer (B1) has 6 or more crosslinkable functional groups from the viewpoint of obtaining a cured product having both a high elastic recovery rate and excellent flexibility. The first crosslinkable (meth)acrylate monomer (B1) may have 7 or more, 8 or more, or 9 or more crosslinkable functional groups. Although the upper limit of the number of crosslinkable functional groups is not particularly limited, it is preferably 20 or less, more preferably 15 or less, and still more preferably 10 or less from the viewpoint of suppressing a decrease in flexibility of the cured product. In addition, the number of hydrogen-bonding crosslinkable functional groups possessed by the first crosslinkable (meth)acrylate monomer (B1) is not particularly limited as long as it is 1 or more. It is preferably 3 or less, more preferably 2 or less, and particularly preferably 1.

Monomers that can be used as the first crosslinkable (meth)acrylate monomer (B1) include, for example, dipentaerythritol penta(meth)acrylate (number of crosslinkable functional groups: 6, of which the number of (meth)acrylic groups: 5, number of hydroxyl groups: 1), dipentaerythritol tetra(meth)acrylate (number of crosslinkable functional groups: 6, of which, number of (meth)acrylic groups: 4, number of hydroxyl groups: 2), tripentaerythritol hexa (Meth) acrylate (number of crosslinkable functional groups: 8, of which, number of (meth)acrylate groups: 6, number of hydroxyl groups: 2), tripentaerythritol penta (meth) acrylate (number of crosslinkable functional groups: 8 , among which, the number of (meth)acrylate groups: 5, the number of hydroxyl groups: 3), succinic anhydride addition-modified dipentaerythritol penta(meth)acrylate (the number of crosslinkable functional groups: 6, of which (meth)acrylate number of groups: 5, number of carboxyl groups: 1), sorbitol penta(meth)acrylate (number of crosslinkable functional groups: 6, of which, number of (meth)acrylic groups: 5, number of hydroxyl groups: 1), caprolactone Modified dipentaerythritol penta(meth)acrylate (number of crosslinkable functional groups: 6, of which, number of (meth)acrylic groups: 5, number of carboxyl groups: 1), adipic acid-modified dipentaerythritol penta(meth)acrylate (Number of crosslinkable functional groups: 6, among which, number of (meth)acrylic groups: 5, number of carboxy groups: 1), salicylic acid-modified dipentaerythritol penta(meth)acrylate (number of crosslinkable functional groups: 6, Among them, the number of (meth)acrylic groups: 5, the number of hydroxyl groups: 1) and the like can be applicable. These monomers may be used alone or in combination of two or more.

<Second crosslinkable (meth)acrylate monomer (B2)>
The second crosslinkable (meth)acrylate monomer (B2) has 6 or more crosslinkable functional groups, and the number of hydrogen-bonding crosslinkable functional groups in the crosslinkable functional groups is the first crosslinkable (meth) It is less than the number of hydrogen-bonding crosslinkable functional groups possessed by the acrylate monomer (B1). At least one crosslinkable functional group of the second crosslinkable (meth)acrylate monomer (B2) is an acryloyl group or a methacryloyl group.

The second crosslinkable (meth)acrylate monomer (B2) has 6 or more crosslinkable functional groups from the viewpoint of obtaining a cured product having both a high elastic recovery rate and excellent flexibility. The second crosslinkable (meth)acrylate monomer (B2) may have 7 or more, 8 or more, or 9 or more crosslinkable functional groups. Although the upper limit of the number of crosslinkable functional groups is not particularly limited, it is preferably 30 or less, more preferably 25 or less, and still more preferably 20 or less from the viewpoint of solubility in a developer. If the number of hydrogen-bonding crosslinkable functional groups possessed by the second crosslinkable (meth)acrylate monomer (B2) is less than the number of hydrogen-bonded crosslinkable functional groups possessed by the first crosslinkable (meth)acrylate monomer (B1), There is no particular limitation, and the difference from the number of hydrogen-bonding crosslinkable functional groups possessed by the first crosslinkable (meth)acrylate monomer (B1) is one, two, or three. can do. In addition, from the viewpoint of suppressing excessive decrease in elasticity and hardness of the cured product, the number of hydrogen-bonding crosslinkable functional groups possessed by the second crosslinkable (meth)acrylate monomer (B2) is preferably 1 or less. , 0.

Monomers that can be used as the second crosslinkable (meth)acrylate monomer (B2) include, for example, dipentaerythritol hexa(meth)acrylate (number of crosslinkable functional groups: 6, of which the number of (meth)acrylic groups: 6), sorbitol hexa(meth)acrylate (number of crosslinkable functional groups: 6, of which, number of (meth)acrylic groups: 6), tripentaerythritol octa(meth)acrylate (number of crosslinkable functional groups: 8, Among them, the number of (meth)acrylic groups: 8) and the like can be mentioned. In addition, the monomers exemplified in the first crosslinkable (meth)acrylate monomer (B1) described above also have a relationship with the number of hydrogen-bonding crosslinkable functional groups possessed by the first crosslinkable (meth)acrylate monomer (B1). It can be used as the second crosslinkable (meth)acrylate monomer (B2) provided that it satisfies the above conditions. These monomers may be used alone or in combination of two or more.

The first crosslinkable (meth)acrylate monomer (B1) and the second crosslinkable (meth)acrylate monomer (B2) are often obtained as a mixture containing both monomers, and commercial products are also products containing both monomers. It may be for sale. The mixing ratio of both monomers can be controlled, for example, by adjusting the conditions when alcohol and (meth)acrylic acid are esterified to produce a mixture containing both monomers. Methods for adjusting the conditions during production include, for example, the mass ratio of alcohol and (meth)acrylic acid during esterification, the reaction time, the reaction temperature, and the purification method and purification time of the product obtained by esterification. and other known methods. The same applies when the first crosslinkable (meth)acrylate monomer is a modified product. The mixture may be used alone, or the mixture may be further mixed and used. Also, if each monomer can be obtained and manufactured as a single item rather than a mixture, these may be used. These may be used alone or in combination.

<Other monomers>
The monomer group (B) contains known monomers other than the first crosslinkable (meth)acrylate monomer (B1) and the second crosslinkable (meth)acrylate monomer (B2) within a range that does not impair the effects of the present invention. You may

[Photoinitiator (C)]
The photopolymerization initiator (C) is not particularly limited. - Acetophenones such as dichloroacetophenone; Anthraquinones such as 2-methylanthraquinone, 2-amylanthraquinone, 2-t-butylanthraquinone, 1-chloroanthraquinone; 2,4-dimethylthioxanthone, 2,4-diisopropylthioxanthone, 2- thioxanthones such as chlorothioxanthone; ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal; benzophenones such as benzophenone; 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1; acylphosphine oxides and xanthones; These photopolymerization initiators may be used alone or in combination of two or more.

[Photosensitive resin composition]
The photosensitive resin composition of the present invention has the viewpoint of obtaining a cured product that has both a high elastic recovery rate and excellent flexibility, improves the solubility in a developer, and reduces the height variation of the cured product. From the viewpoint of suppression, etc., it is preferable to contain 80 to 200 parts by mass of the monomer group (B) with respect to 100 parts by mass of the alkali-soluble resin (A), and more preferably 100 to 170 parts by mass. , more preferably 120 to 150 parts by mass. At this time, the monomer group (B) preferably contains 80 parts by mass or more in total of the first crosslinkable (meth)acrylate monomer (B1) and the second crosslinkable (meth)acrylate monomer (B2). In particular, from the viewpoint of improving the elastic recovery rate, the first crosslinkable (meth)acrylate monomer (B1) and the second crosslinkable (meth)acrylate monomer (B2) are added to 100 parts by mass of the alkali-soluble resin (A). is preferably contained in a total of 100 parts by mass or more, more preferably 120 parts by mass or more. In addition, from the viewpoint of suppressing variations in the height of the cured product and ensuring good solubility in the solvent when using a solvent, the first crosslinkability (meta ) The acrylate monomer (B1) and the second crosslinkable (meth)acrylate monomer (B2) preferably contain a total of 200 parts by mass or less, more preferably 170 parts by mass or less, and 150 parts by mass or less. is more preferred.

The photosensitive resin composition of the present invention has the viewpoint of obtaining a cured product that has both a high elastic recovery rate and excellent flexibility, improves the solubility in a developer, and reduces the height variation of the cured product. From the viewpoint of suppressing the 1 is preferred, 1:5 to 5:1 is more preferred, 1:3 to 3:1 is even more preferred, and 1:2 to 2:1 is particularly preferred.

The content of the photopolymerization initiator (C) is not particularly limited, but from the viewpoint of solubility and curability of the photosensitive resin composition, 1 to 60 parts by weight with respect to 100 parts by weight of the alkali-soluble resin (A). is preferably 3 to 40 parts by weight, more preferably 4 to 35 parts by weight, and particularly preferably 6 to 25 parts by weight.

The photosensitive resin composition of the present invention may contain a photopolymerization initiation aid. Examples of photopolymerization initiation aids include 1,3,5-tris(3-mercaptopropionyloxyethyl)-isocyanurate, 1,3,5-tris(3-mercaptobutyloxyethyl)-isocyanurate (Showa Denko manufactured by Karenz MT (registered trademark) NR1), trifunctional thiol compounds such as trimethylolpropane tris (3-mercaptopropionate); butyrate) (manufactured by Showa Denko Co., Ltd., Karenz MT (registered trademark) PEI) and other tetrafunctional thiol compounds; dipentaerythritol hexakis (3-propionate) and other hexafunctional thiol compounds. These photopolymerization initiation aids may be used alone or in combination of two or more.

The photosensitive resin composition of the present invention may contain a thermal polymerization initiator. Thermal polymerization initiators include, for example, cumene hydroperoxide, diisopropylbenzene peroxide, di-t-butyl peroxide, lauryl peroxide, benzoyl peroxide, t-butylperoxyisopropyl carbonate, t-butylperoxy-2 -organic peroxides such as ethylhexanoate and t-amylperoxy-2-ethylhexanoate; 2,2'-azobis(isobutyronitrile), 1,1'-azobis(cyclohexanecarbonitrile), azo compounds such as 2,2'-azobis(2,4-dimethylvaleronitrile) and dimethyl 2,2'-azobis(2-methylpropionate); These thermal polymerization initiators may be used alone or in combination of two or more.

The photosensitive resin composition of the present invention may contain radically polymerizable oligomers such as unsaturated polyesters, epoxy acrylates, urethane acrylates and polyester acrylates; curable resins such as epoxy resins.

The photosensitive resin composition of the present invention may contain a solvent. Examples of solvents 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; mentioned. These solvents may be used alone or in combination of two or more. In addition, the content of the solvent may be appropriately set according to the optimum viscosity when using the composition.

The photosensitive resin composition of the present invention contains fillers such as aluminum hydroxide, talc, clay, barium sulfate, etc., dyes, pigments, antifoaming agents, coupling agents, leveling agents, Known additives such as sensitizers, release agents, lubricants, plasticizers, antioxidants, UV absorbers, flame retardants, polymerization inhibitors, thickeners and dispersants may be contained.

[Hardened material]
The cured product of the present invention is obtained by curing the photosensitive resin composition. As a method for producing a cured product of the present invention, for example, the photosensitive resin composition is injected into a molding mold (resin mold), and if necessary, heating (prebaking) is performed to the extent that the shape can be maintained. After curing and removing from the mold, or after coating the photosensitive resin composition on a base material (substrate) or various functional layers to form a desired shape, light (for example, ultraviolet rays) is irradiated. and a method of curing the photosensitive resin composition. Curing conditions may be appropriately adjusted according to the photosensitive resin composition to be used.

The cured product is suitably used as a photospacer, partition wall material, lens material, interlayer insulating film material, protective film material, optical waveguide material, or flattening film material, and is particularly suitably used as a photospacer.

[Photospacer]
The method for forming the photospacer is not particularly limited, and for example, the photosensitive resin composition may be applied to a substrate such as glass or a transparent plastic film, dried to form a coating film, and then formed by photolithography. can. In photolithography, for example, a photomask is placed on the coating film, the coating film is photocured by irradiating with ultraviolet rays, and an alkaline aqueous solution is sprayed on the coating film after the ultraviolet irradiation to dissolve and remove the unexposed areas. The remaining exposed portions are washed with water and developed to form photospacers. A post-bake may then be performed.

The shape of the photospacer is not particularly limited, but examples include a cylindrical shape, a prismatic shape, a truncated cone shape, a truncated pyramid shape, and the like.

Since the photospacer of the present invention has a high elastic recovery rate, it can effectively suppress the fluctuation of the cell gap due to stress during use of the liquid crystal display device. It is difficult to damage the alignment film of the substrate on the TFT side (the alignment film is less likely to be scraped).

Although the present invention will be described with reference to examples below, the present invention is not limited by these examples.

Production example 1
[Synthesis of alkali-soluble resin (A-1)]
100 parts by mass of glycidyl methacrylate (GMA) and 150 parts by mass of propylene glycol monomethyl ether acetate (PGMAc) were placed in a glass flask equipped with a heating/cooling/stirring device, a reflux condenser, and a nitrogen inlet tube. After replacing the gas phase in the system with nitrogen, 8.7 parts by mass of 2,2′-azobis(2,4-dimethylvaleronitrile) was added, heated to 80° C., and reacted at the same temperature for 8 hours. rice field. To the obtained solution, 80 parts by mass of acrylic anhydride, 15 parts by mass of acrylic acid (AA), 2.0 parts by mass of tetrabutylammonium chloride, 0.3 parts by mass of hydroquinone, and 173 parts by mass of propylene glycol monomethyl ether acetate are added. and reacted at 70° C. for 12 hours. After that, 14 parts by mass of succinic anhydride was added to the solution after the reaction and reacted at 70° C. for 6 hours to obtain a 40% by mass solution of alkali-soluble resin (A-1). The alkali-soluble resin (A-1) had an acid value of 37.4 mgKOH/g, a weight average molecular weight (Mw) of 24,000 by GPC, and a double bond equivalent of 154 g/mol.

Production example 2
[Synthesis of alkali-soluble resin (A-2)]
686 parts by mass of PGMAc, 332 parts by mass of GMA, and 6.6 parts by mass of azobisisobutyronitrile (AIBN) were placed in a glass flask equipped with a heating/cooling/stirring device, a reflux condenser, and a nitrogen inlet tube. The system was heated at 80° C. for 6 hours while nitrogen was blown into the system to obtain a solution of polymer in which GMA was polymerized (GMA polymer). To the resulting GMA polymer solution, 168 parts by mass of acrylic acid (AA), 0.05 parts by mass of methoquinone (MQ), and 0.5 parts by mass of triphenylphosphine (TPP) were added, and the mixture was heated at 100°C while blowing air. After heating for 24 hours, a solution of acrylic acid adduct of GMA polymer was obtained. 186 parts by mass of tetrahydrophthalic anhydride was added to the solution of acrylic acid adduct of GMA polymer and heated at 70° C. for 10 hours to obtain a 50.2% by mass solution of alkali-soluble resin (A-2). The alkali-soluble resin (A-2) had an acid value of 99 mgKOH/g and a double bond equivalent of 294 g/mol.

Production example 3
[Synthesis of monomer mixture α]
1557.5 parts by mass of dipentaerythritol, 3442.5 parts by mass of 98% acrylic acid, and 7.5 parts by mass of p-methoxyphenol were added to a reaction apparatus equipped with a cooling tube with a water separator, a stirrer, a thermometer and an air blowing tube. , 250 parts by mass of p-toluenesulfonic acid, and 750 parts by mass of cyclohexane were charged. Then, while blowing air into the reaction solution at a flow rate of 300 ml/min, the temperature in the reaction system was raised to 85° C. over 1 hour to reflux cyclohexane. While maintaining the temperature at 85 to 92° C., the reflux was continued and the produced water was removed from the system. During the reaction, the reaction solution was analyzed at any time by high performance liquid chromatography (HPLC) under the following conditions, and about 30% by mass of the reaction solution was dipentaerythritol pentaacrylate (DPEPA), and about 70% by mass was dipentaerythritol hexaacrylate. The reaction was terminated in the state of (DPEHA), and reaction solution A was obtained.
(Composition analysis in reaction liquid A)
Apparatus Waters HPLC (manufactured by Nihon Millipore)
Column YMC PACK ODS (Yamamura Chemical Laboratory)
detector Rl
Mobile phase methanol/water = 7/3
Flow rate 1ml/min

(Neutralization, washing process)
515.6 parts by mass of reaction liquid A, 103.1 parts by mass of cyclohexane and 412.5 parts by mass of toluene were placed in a beaker, and then 240.8 parts by mass of a 20% sodium hydroxide aqueous solution was gradually added with stirring. Unreacted acrylic acid was neutralized by stirring for 30 minutes. Then, the neutralized liquid was transferred to a separating funnel and allowed to stand still for 1 hour to remove the aqueous layer to complete the neutralization process. Further, 257.8 parts by mass of deionized water was added to the separating funnel, vigorously shaken, and allowed to stand still for 1 hour to remove the water layer. This water washing operation was repeated twice (a total of three water washing operations), and the water washing step was completed. As a result, 831.8 parts by mass of a pale yellow organic layer was obtained. 0.07 parts by mass of p-methoxyphenol was added to the total amount of the organic layer, and the organic solvent was distilled off by decompressing while blowing a small amount of air to obtain 328.7 parts by mass of a purified product. Then, the content of p-methoxyphenol in the purified product was adjusted to 500 ppm.

(denaturation step)
Into a 500 mL reaction vessel equipped with a stirrer, a condenser, and a thermometer, 250 parts by mass of the p-methoxyphenol content adjusted to 500 ppm, 16 parts by mass of succinic anhydride, and 0.13 parts by mass of MQ was added and the temperature was raised to 85°C. After adding 1.3 parts by mass of triethylamine (TEA) thereinto, a reaction was carried out for a time at 80° C. in a mixed atmosphere of oxygen/nitrogen (oxygen:nitrogen=5:95 volume ratio) to obtain a monomer mixture α. Obtained. The monomer mixture α contains succinic anhydride addition-modified dipentaerythritol penta(meth)acrylate (AM-DPEPA, number of crosslinkable functional groups: 6, of which, number of acrylic groups: 5, number of carboxyl groups: 1). about 30 parts by weight, containing about 70 parts by weight of DPEHA.

Production example 4
[Synthesis of monomer mixture β]
A monomer mixture β was obtained in the same manner as in Production Example 3 above, except that the modification step was not performed. The monomer mixture β is a mixture of DPEPA and DPEHA, and the mass ratio thereof is DPEPA:DPEHA=about 30 parts by mass:about 70 parts by mass.

Production example 5
[Synthesis of monomer mixture γ]
A monomer mixture γ was obtained in the same manner as in Production Example 3 above, except that the modification step was not performed. The monomer mixture γ is a mixture of DPEPA and DPEHA, and the weight ratio thereof is DPEPA:DPEHA=about 37.5 parts by weight:about 62.5 parts by weight.

Example 1
[Preparation of photosensitive resin composition]
250 parts by mass of 40% by mass solution of alkali-soluble resin (A-1) (content of alkali-soluble resin (A-1): 100 parts by mass), 40 parts by mass of monomer mixture α as monomer group (B), 80 parts by mass of monomer mixture β Parts by mass, 6 parts by mass of the product name IrgacureOXE01 (manufactured by BASF Japan Ltd.) as a photopolymerization initiator (C), and 2.5 parts by mass of the product name Tinuvin 479 (manufactured by BASF Japan Ltd.) as an ultraviolet absorber. , a photosensitive resin composition having a solid content of 2.6% by mass was prepared. The first crosslinkable (meth)acrylate monomer (B1) in the monomer group (B) corresponds to AM-DPEPA and DPEPA, and the total content thereof was 68 parts by mass. DPEHA corresponds to the second crosslinkable (meth)acrylate monomer (B2), and its content was 52 parts by mass. Moreover, the acid value as the monomer group (B) was 8 mgKOH/g, and the hydroxyl value was 53 mgKOH/g.

Examples 2-4 and Comparative Examples 1-8
A photosensitive resin composition was prepared in the same manner as in Example 1, except that the composition was changed to that shown in Table 1. The unit of the numerical values in Table 1 is parts by mass, and in the monomer group (B), the content ratio is indicated by a range due to the characteristics of the product, and the value calculated from this content is within this range. The values obtained from the maximum and minimum values of are described as ranges. Further, the product names and manufacturers of the monomer group (B) in Table 1 that are not described above, the photopolymerization initiator (C) and the ultraviolet absorber are as follows.

Monomer group (B)
・Viscoat #295 (manufactured by Osaka Organic Chemical Industry Co., Ltd., trimethylolpropane triacrylate, number of crosslinkable functional groups: 3, number of acrylic groups: 3, number of hydroxyl groups: 0)
- Viscoat #700 (manufactured by Osaka Organic Chemical Industry Co., Ltd., EO 3.8 mol adduct diacrylate of bisphenol A, number of crosslinkable functional groups: 2, number of acrylic groups: 2, number of hydroxyl groups: 0)
・Viscoat #802 (manufactured by Osaka Organic Chemical Industry Co., Ltd., a mixture of 55 to 85 parts by mass of tripentaerythritol acrylate, 10 to 20 parts by mass of mono- and dipentaerythritol acrylate, and 5 to 15 parts by mass of polypentaerythritol acrylate)
DPEA-12 (manufactured by Nippon Kayaku Co., Ltd., ethylene oxide-modified dipentaerythritol hexaacrylate, number of crosslinkable functional groups: 6, of which, number of acrylic groups: 6, number of hydroxyl groups: 0)

Photoinitiator (C)
・ TR-PBG-304: Trade name TR-PBG-304 (manufactured by Changzhou Strong Advanced Electronic Materials Co., Ltd.)
・ OXE-01: Product name Irgacure OXE01 (manufactured by BASF Japan Ltd.)
・Irg-819: trade name Irgacure 819
・EMK: SPEEDCURE EMK (manufactured by LAMBSON)
・ NCI-100: Product name Adeka Arcles NCI-100 (manufactured by Adeka Co., Ltd.)

Ultraviolet absorber SEESORB 106: trade name SEESORB 106 (manufactured by Shipro Kasei Co., Ltd.)
・ Tinuvin 479: Product name Tinuvin 479 (manufactured by BASF Japan Ltd.)

[Measurement and evaluation method]
(Elastic recovery rate)
Each of the photosensitive resin compositions prepared in Examples 1 to 4 and Comparative Examples 1 to 8 was applied onto each glass substrate having a size of 10 cm×10 cm using a spin coater to form a coating film. Then, the resulting coating film was heated on a hot plate at 90° C. for 2 minutes to completely remove the solvent in the coating film. After that, the obtained coating film is passed through a plurality of photospacer forming masks having 100 openings per 1 cm ² with different diameters of 6, 8, 9, 10, or 11 μm in diameter, and light from an ultra-high pressure mercury lamp. was taken out with a band-pass filter and irradiated with 90 mJ/cm ² (irradiance of 33 mW/cm ² in terms of i-line). The distance (exposure gap) between the mask and the substrate was 50 μm during exposure. Thereafter, development was performed using a 0.3% Na ₂ CO ₃ aqueous solution, washing with water, and heating at 230° C. for 30 minutes to form a plurality of photospacers of different sizes. A photospacer having an upper bottom surface diameter of 7 μm, a lower bottom surface diameter of 10 μm, and a height of 3 μm was selected from the obtained photospacers, and the elastic recovery rate was measured by the following method. Here, the definition of upper base and lower base is as follows.
Upper base: diameter of 90% part when film thickness is 100% Lower base: diameter of 10% part when film thickness is 100% Using a hardness tester (manufactured by Fischer Instruments, product name: FISCHERSCOPE HM-2000), a flat indenter with a diameter of 50 μm is used to apply a load of up to 40 mN at both a loading speed and an unloading speed of 2.0 mN / sec. After that, it was held for 5 seconds, then unloaded to 0 mN, held for 5 seconds, and a load-deformation curve at the time of loading and a load-deformation curve at the time of unloading were created. The elastic recovery rate was calculated according to the following formula, with the amount of deformation at a load of 40 mN under load being L1 and the amount of deformation at a load of 0 mN under unloading being L2, and evaluated according to the following criteria.
Elastic recovery rate (%) = {(L1-L2) × 100] / L1
<Evaluation Criteria>
A: Elastic recovery rate of 85% or more B: Elastic recovery rate of 80% or more and less than 85% C: Elastic recovery rate of 70% or more and less than 80% F: Elastic recovery rate of less than 70%

(High temperature repeated pressing resistance)
Using the photosensitive resin compositions prepared in Examples 1 to 4 and Comparative Examples 1 to 3 and 5, photospacers having a height of 2.5 μm, a line width of 10 μm on the upper bottom surface, and a line width of 14 μm on the lower bottom surface were formed on a glass substrate. Created in the same manner as above, with the above microhardness tester, maximum load 30 mN, load speed 3.33 mN / sec, maximum load holding time 5 seconds, minimum load 0.2 mN, unloading speed 3.33 mN /s was defined as one cycle, and a repeated pressing test was performed for 250 cycles. The test was performed at 23 to 25° C. near room temperature and at 80° C. under heating, and the height of each photospacer before and after the pressing test was measured with a white interferometer to evaluate the difference in height before and after the test. The height change before and after the repeated pressing test at room temperature was defined as ΔH1, and the height change before and after the repeated pressing test at 80° C. was defined as ΔH2. In Comparative Examples 4 and 6 to 8, no measurement was performed, but since the acid value of the monomer group (B) is 0, it is assumed that it is F when any comparative example is evaluated. be done. In Table 1, estimated values are shown in parenthesis, and the same applies to other evaluations.
<Evaluation Criteria>
A: Height change ΔH1: 0 μm ≤ ΔH1 ≤ 0.1 μm, ΔH2 - ΔH1 ≤ 0.02 μm
B: Height change ΔH1: 0.1 μm<ΔH1≦0.15 μm, ΔH2−ΔH1≦0.04 μm
F: Height change ΔH1: 0.15 μm<ΔH1, or ΔH2−ΔH1>0.40 μm

(Resistant to damage)
The photosensitive resin compositions prepared in Examples 1 to 4 and Comparative Examples 1 to 8 were applied onto a glass substrate, and the dried pre-baked film was subjected to an exposure amount of 100 mJ/cm ² (i-line) using an ultra-high pressure mercury lamp. converted), developed, and heated in an oven at a temperature of 230° C. for 40 minutes to form a cured film having a thickness of 3 μm. Each cured film was subjected to a pencil hardness test according to JIS K 5600-5-4:1999 and evaluated according to the following criteria.
<Evaluation Criteria>
A: Pencil hardness less than 5H F: Pencil hardness 5H or more

(developer solubility)
The photosensitive resin compositions prepared in Examples 1 to 4 and Comparative Examples 1 to 6 and 8 were applied on a glass substrate by spin coating, dried under reduced pressure, and then allowed to stand for 2 minutes on a hot plate heated to 90°C. bottom. After dissipating heat from the glass substrate, put the glass substrate in a petri dish with a diameter of 12 cmφ so that the coating surface faces upward, add 50 mg of a developer (manufactured by ADEKA, CD-379, 20 times pure water diluted solution), and add the petri dish for 2 minutes. was shaken horizontally, and then the lysate was collected. The turbidity of the sampled solution was measured using a HACH turbidity meter 2100Q and evaluated according to the following criteria. Although no measurement was performed in Comparative Example 7, the monomer group (B) had an acid value of 0, and the first crosslinkable (meth)acrylate monomer (B1) and the second crosslinkable (meth)acrylate monomer (B1) ) and the acrylate monomer (B2), it is assumed to be F when evaluated.
<Evaluation Criteria>
A: Transparent (turbidity less than 10)
B: Cloudy (turbidity of 10 or more and less than 100)
C: Cloudy (turbidity of 100 or more)
F: Many deposits

(Height variation (scan unevenness, lens unevenness))
The substrate with a protective film was washed with a UV/ozone device at a predetermined exposure amount, and the photosensitive resin compositions prepared in Examples 1 to 4 and Comparative Examples 1 to 8 were applied to the substrate with a protective film using a spin coater. painted on top. This was heat-dried (pre-baked) for 10 minutes in an inert oven at 105° C. to form a coating film having a thickness of 3.50 μm. Next, the substrate was cooled to room temperature and exposed through a negative photomask (○ (round) pattern design φ of 10 μm) using a multi-lens scanning system.
Next, it was subjected to shower development with an automatic developing device, washed with water and air-dried. Finally, heat drying (post-baking) was performed in an inert oven at 230° C. for 30 minutes to form a ○ (round) pattern photospacer.
Among the formed photo-spacers, in a 20 mm square range in the substrate surface corresponding to the joint portion between the lenses, 20 mm squares were arranged at regular intervals in the direction perpendicular to the arrangement of the lenses in two rows in the substrate surface. The variation in height (maximum height - minimum height) of individual photospacers was measured with a step measuring instrument, and the scan unevenness of the photospacers was evaluated according to the following criteria.
<Evaluation Criteria>
A: Variation in height of photospacer is less than 0.03 μm F: Variation in height of photospacer is 0.03 μm or more

The photosensitive resin composition of the present invention is suitably used as a material for forming photospacers.

Claims (8)

an alkali-soluble resin (A) having a double bond equivalent of 200 g/mol or less;
A first crosslinkable (meth)acrylate monomer (B1) having six or more crosslinkable functional groups, at least one of which is a hydrogen-bonding crosslinkable functional group, and six or more crosslinkable It has a functional group, and the number of hydrogen-bonding crosslinkable functional groups in the crosslinkable functional group is greater than the number of the hydrogen-bonding crosslinkable functional groups in the first crosslinkable (meth)acrylate monomer (B1). a monomer group (B) containing a small amount of the second crosslinkable (meth)acrylate monomer (B2) and having an acid value of 1 to 20 mgKOH/g;
A photosensitive resin composition containing a photopolymerization initiator (C). The photosensitive resin composition according to claim 1, wherein the monomer group (B) has a hydroxyl value of 15 to 70 mgKOH/g. The photosensitive resin composition according to claim 1 or 2, wherein the second crosslinkable (meth)acrylate monomer (B2) does not have a hydrogen-bonding crosslinkable functional group. The photosensitive resin composition according to any one of claims 1 to 3, containing 80 to 200 parts by mass of the monomer group (B) with respect to 100 parts by mass of the alkali-soluble resin (A). 1. The mass ratio (B1:B2) between the first crosslinkable (meth)acrylate monomer (B1) and the second crosslinkable (meth)acrylate monomer (B2) is 1:10 to 10:1. 5. The photosensitive resin composition according to any one of 4. A cured product obtained from the photosensitive resin composition according to any one of claims 1 to 5. The cured product according to claim 6, wherein the cured product is a photospacer, partition wall material, lens material, interlayer insulating film material, protective film material, optical waveguide material, or flattening film material. An image display device comprising the cured product according to claim 6 or 7.