JP7309609B2 - Photosensitive resin composition for forming photospacer, method for forming photospacer, substrate with photospacer, and color filter - Google Patents

Description

TECHNICAL FIELD The present invention relates to a photosensitive resin composition for forming a photospacer, a method for forming a photospacer, a substrate with a photospacer, and a color filter, and a photosensitive resin composition for forming a photospacer which is particularly useful for projection exposure (lens scanning exposure). The present invention relates to a product, a method for forming a photospacer using the same, a substrate with a photospacer, and a color filter.

Conventionally, in the technology of liquid crystal display devices, a member called a spacer has been used to maintain the thickness of a liquid crystal layer sandwiched between a color filter side substrate and a thin film transistor (TFT) side substrate. ing. As for the formation of the spacers, a columnar resin member called a photospacer is formed on a desired position, for example, a grid-like black matrix formed between pixels by photolithography using a photosensitive resin. Many methods are used.

Also, when forming the photospacer, a photomask is usually used for patterning. As an exposure method using a photomask, the proximity method has been conventionally adopted, but in recent years, with the increase in the size of glass substrates and the resolution of pixels, projection exposure using a multi-lens system (lens scan ) method is employed (see, for example, Patent Document 1 below).

In the projection exposure method using a plurality of lenses, the amount of exposure is smaller in the portion corresponding to the joint portion between the lenses than in the normal portion located directly below the lens. Therefore, in the area corresponding to the joint portion of the lens, it is designed so that the amount of exposure becomes the same as that of the normal portion by exposing the coating film a plurality of times. However, even when the amount of exposure is adjusted, variations in the height of the photospacer called "lens unevenness" may occur at the joints of the lenses, and there is a demand for improvement. As a technique for improving lens unevenness, for example, an alkali-soluble resin and a polymerizable compound are contained, and the proportion of the polymerizable compound having a molecular weight of 700 or more in the polymerizable compound is 35 to 65% by mass. , a technique using a photosensitive resin composition has been proposed (see, for example, Patent Document 2 below).

JP-A-7-183212 JP 2016-184072 A

According to the technique described in Patent Document 2, by forming a photospacer using the photosensitive resin composition described above, it is possible to suppress the occurrence of variations in the height of the photospacer when exposed by a lens scanning method. there is However, in recent years, there has been a high demand for uniformity in the height of photospacers, and there is still room for improvement in order to meet these demands.

Furthermore, as a problem after forming the liquid crystal panel, an external force or impact may be applied to the liquid crystal panel by pressing the surface of the liquid crystal panel with a finger. At this time, if the photospacer is crushed, the cell gap is partially reduced, which may cause display failure. Therefore, in order to prevent display defects caused by an external force or the like, the photospacer is required to have a high restoration rate.

In order to solve the above problems, the present invention provides a photosensitive resin composition for forming a photospacer capable of forming a photospacer excellent in height uniformity and restoration rate, and a photospacer using the same. , a substrate with a photospacer, and a color filter.

The present inventors have made extensive studies to solve the above problems. As a result, the present inventors have found that the above-described problems can be achieved by setting the mass ratio of the specific oligomer to the alkali-soluble polymer within a certain range, and have completed the present invention.

<1> Contains an alkali-soluble resin and an oligomer having a weight average molecular weight of 1000 or more, wherein the mass ratio [O/P ratio] between the alkali-soluble resin [P] and the oligomer [O] is 0.4 to 1.0 of the photosensitive resin composition for forming a photospacer.
<2> The photosensitive resin composition for forming a photospacer according to <1>, wherein the alkali-soluble resin has a weight average molecular weight of 5,000 to 100,000.
<3> The photosensitive resin composition for forming a photospacer according to <1> or <2>, wherein the alkali-soluble resin is an acrylic resin.
<4> The photosensitive resin composition for forming a photospacer according to any one of <1> to <3>, wherein the alkali-soluble resin has a double bond equivalent of 100 to 270.
<5> The photosensitive resin composition for forming a photospacer according to any one of <1> to <4>, further comprising a photopolymerization initiator.
<6> A coating film containing the photosensitive resin composition for forming a photospacer according to any one of <1> to <5> is formed on a substrate, and the coating film is exposed and developed to form a photospacer. A method of forming a photospacer that forms a
<7> The method for forming a photospacer according to <6>, wherein the exposure is projection exposure.
<8> A photospacer comprising a substrate and a photospacer provided on the substrate and obtained by curing the photosensitive resin composition for forming a photospacer according to any one of <1> to <5>. attached board.
<9> A substrate, a colored layer provided on the substrate, and the photosensitive resin composition for forming a photospacer provided on the colored layer according to any one of <1> to <5>. a hardened photospacer; and a color filter.
<10> The color filter according to <9>, wherein the colored layer comprises a black matrix layer.
<11> The color filter according to <10>, wherein the photospacer is provided on the black matrix layer.

INDUSTRIAL APPLICABILITY According to the present invention, a photosensitive resin composition for forming a photospacer capable of forming a photospacer excellent in height uniformity and restoration rate, a method for forming a photospacer using the same, and a photospacer An attached substrate and a color filter can be provided.

EMBODIMENT OF THE INVENTION Hereinafter, the form (henceforth "this embodiment") for implementing this invention is demonstrated in detail. However, the present invention is not limited to this, and various modifications are possible without departing from the scope of the invention.

<<Photosensitive resin composition for forming photospacer>>
The photosensitive resin composition for forming a photospacer of the present embodiment (hereinafter sometimes simply referred to as "resin composition") contains an alkali-soluble resin and an oligomer having a weight average molecular weight of 1000 or more, The mass ratio [O/P ratio] between the alkali-soluble resin [P] and the oligomer [O] is 0.4 to 1.0.

According to the resin composition of the present embodiment, height uniformity and recovery rate are achieved by using an alkali-soluble resin and an oligomer having a weight average molecular weight of 1000 or more in an O/P ratio range of 0.4 to 1.0. An excellent photospacer can be formed. The resin composition of the present embodiment is particularly suitable for a method of forming a photospacer that employs a projection exposure (lens scanning) method using a multi-lens system, and the normal portion in the joint portion between the lenses is an irradiation method. Even if the exposure dose is different from the normal part (irradiating the same exposure amount in multiple times), there is little variation in the height between the obtained photospacers, and the occurrence of so-called "lens unevenness" can be suppressed. . In other words, since the coating film formed using the resin composition of the present embodiment is less susceptible to the irradiation method during exposure, variations in the height of the photospacer are suppressed even at the joint portion of the lens. be able to. Furthermore, by using the resin composition of the present embodiment, it is possible to form a photospacer having a sufficient restoration rate while suppressing the occurrence of lens unevenness.
Note that the above-mentioned lens unevenness is not only due to variations in height between photospacers, but for one pixel (photospacer), when a cross section in the thickness direction is observed, the height of the center part of the upper surface and the height of the edge part This includes cases where there is a difference in Although not particularly limited, if a photospacer is formed using the resin composition of the present embodiment, the height difference (maximum height - minimum height) of the photospacer due to lens unevenness is 0.02 μm or less. is also possible.

(alkali-soluble resin)
In this embodiment, the alkali-soluble resin is a polymer having a weight average molecular weight of 5,000 or more and an alkali-soluble group. The weight average molecular weight of the alkali-soluble resin is preferably 5,000 to 100,000, more preferably 7,000 to 50,000, more preferably 10,000 to 30, 000 is particularly preferred. The molecular weight of the alkali-soluble resin is measured by gel permeation chromatography (manufactured by Tosoh Corporation, product number: HLC-8120, column: two connections of G-5000HXL and G-3000HXL, detector: RI, mobile phase: tetrahydrofuran). can do.

Examples of the alkali-soluble resin include, but are not limited to, acrylic resins, novolac resins, etc. Acrylic resins are particularly preferred. The double bond equivalent of the alkali-soluble resin is preferably 100 to 270 from the viewpoint of increasing the restoration rate of the photospacer. Here, "double bond equivalent" refers to the number of grams of the resin composition per 1 mol of acryloyl groups. Also, the term "the number of grams of the resin composition" means the mass of the entire resin composition (excluding the solvent).

The acid value of the alkali-soluble resin is preferably 10 to 200 in terms of solid content from the viewpoint of suppressing the occurrence of defects such as poor development in alkali development and erosion of the surface of the exposed portion by the developer. , 20 to 120 are more preferred, and 30 to 60 are particularly preferred. Methods for adjusting the acid value include a method of adding an acid anhydride to a hydroxyl group, and a method of copolymerizing a carboxylic acid-containing acrylate in the case of an acrylic resin.

Examples of the alkali-soluble resin include, but are not limited to, acrylic-modified resins made from polyepoxy resins, acrylic-modified resins made from polycarboxylic acid resins, and acrylic-modified resins made from polyalcohol resins.

-Acrylic Modified Resin by Polyepoxy Resin-
The polyepoxy resin used for the acrylic-modified resin with polyepoxy resin is not particularly limited, but examples thereof include phenol novolac epoxy resin and cresol novolak epoxy resin.

Examples of acrylic-modified resins include polymers of one or more epoxy-containing acrylates such as glycidyl (meth)acrylate and other copolymerizable methyl (meth)acrylate, ethyl (meth)acrylate, and propyl (meth)acrylate. , butyl (meth)acrylate, benzyl (meth)acrylate, lauryl (meth)acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, ethoxyethyl (meth)acrylate, and other alkyl (meth)acrylates and cyclohexyl Copolymers with alicyclic (meth)acrylates such as (meth)acrylates, isobornyl (meth)acrylates, and dicyclopentenyl (meth)acrylates are also included. These copolymerizable monomers may be used singly or in combination of two or more. Furthermore, compounds such as styrene, cyclohexylmaleimide, and phenylmaleimide that are copolymerizable with these acrylates can also be copolymerized. As a method for acryl-modifying these polyepoxy resins, they can be obtained by adding carboxylic acid-containing acrylates such as (meth)acrylic acid, (meth)acrylic anhydride, and the like. Moreover, as a method of imparting an acid value to these acrylic-modified resins, it can be obtained by adding a carboxylic acid derivative such as an acid anhydride to a hydroxyl group generated by acrylic addition.

Although not particularly limited, a polymerizable (meth)acrylic polymer represented by the following formula (A) can be used as the alkali-soluble resin. By using a polymerizable (meth)acrylic polymer represented by the following formula (A), the double bond equivalent and acid value of the alkali-soluble resin can be easily adjusted within the preferred range. Each structural unit contained in the polymerizable (meth)acrylic polymer represented by formula (A) may contain different types of structures.

(wherein each R ₁ independently represents a hydrogen atom or a methyl group, and X ₁ , X ₂ , X ₃ , X ₄ and X ₅ each independently represent the following general formula (1) and R ₃ represents either a hydrogen atom or a substituent represented by the following structural formula (X), l, m and n represent the respective monomer units in the form of a ratio of l:m:n. represents the molar ratio of

(Wherein, R ₂ represents a hydrogen atom or a methyl group, and "*-" represents a binding site, provided that the substituent represented by formula (1) bonded to X ₁ or X ₂ in formula (A) is R ₂ is a hydrogen atom.)

(Wherein, "*-" represents a binding site.)

The polymerizable (meth)acrylic polymer represented _by formula (A) is not particularly limited, but the _substituent R Preferably ₂ is a methyl group. Specific examples of the polymerizable (meth)acrylic polymer represented by formula (A) include the acrylic resin (P-1) used in Examples described later.

-Acrylic Modified Resin with Polycarboxylic Acid Resin-
The acrylic-modified resin with a polycarboxylic acid resin is not particularly limited, but for example, one or more polymers of carboxylic acid-containing acrylates such as (meth)acrylic acid and other copolymerizable methyl (meth)acrylates , ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, benzyl (meth)acrylate, lauryl (meth)acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, ethoxyethyl (meth)acrylate Examples thereof include alkyl (meth)acrylates such as acrylate, and copolymers with alicyclic (meth)acrylates such as cyclohexyl (meth)acrylate, isobornyl (meth)acrylate and dicyclopentenyl (meth)acrylate. These copolymerizable monomers may be used singly or in combination of two or more. Furthermore, compounds such as styrene, cyclohexylmaleimide, and phenylmaleimide that are copolymerizable with these acrylates can also be copolymerized. As a method for acrylic modification of polycarboxylic acid resin, it can be obtained by adding epoxy-containing acrylate such as glycidyl (meth)acrylate to polycarboxylic acid.

-Acrylic Modified Resin with Polyalcohol Resin-
The polyalcohol resin used for the acrylic-modified resin with polyalcohol resin is not particularly limited, but examples thereof include polyvinyl alcohol, phenol novolac resin, and cresol novolac resin.

The acrylic-modified resin with the polyalcohol resin is not particularly limited. Examples of the polyalcohol resin include polyvinyl alcohol, phenol novolac resin, and cresol novolac resin, and the acrylic resin includes hydroxyethyl A polymer with one or more hydroxyl group-containing acrylates such as (meth) acrylate, other copolymerizable (meth) acrylate, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl ( Alkyl (meth)acrylates such as meth)acrylate, benzyl (meth)acrylate, lauryl (meth)acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, ethoxyethyl (meth)acrylate, and cyclohexyl (meth)acrylate Copolymers with alicyclic (meth)acrylates such as acrylates, isobornyl (meth)acrylates and dicyclopentenyl (meth)acrylates are also included. These copolymerizable monomers may be used singly or in combination of two or more. Furthermore, compounds such as styrene, cyclohexylmaleimide, and phenylmaleimide that are copolymerizable with these acrylates can also be copolymerized.

Examples of methods for acryl-modifying these polyalcohol resins include a method of adding a carboxylic acid-containing acrylate such as (meth)acrylic acid by dehydration esterification or transesterification, a method of using a desalting addition reaction of an acid chloride-containing acrylate, It can be obtained by, for example, adding an isocyanate-containing acrylate.

The content of the alkali-soluble resin in the resin composition of the present embodiment is not particularly limited, and can be appropriately determined based on the O/P ratio described later. 35 to 75% by mass, more preferably 40 to 70% by mass, particularly preferably 45 to 65% by mass, based on the total solid content in the composition. The term "total solids" used throughout this specification means all components other than the solvent in the resin composition.

(oligomer)
The resin composition of this embodiment contains an oligomer having a molecular weight of 1000 or more. Here, the "oligomer having a weight-average molecular weight of 1000 or more" includes both a mixture of one kind and a plurality of kinds of polymerizable compounds. However, when the oligomer is a mixture of a plurality of types of polymerizable compounds, it is composed only of polymerizable compounds having a weight-average molecular weight of less than 5,000. From the viewpoint of effectively suppressing the occurrence of lens unevenness, the weight average molecular weight of the oligomer in the present embodiment is preferably 1,000 or more and less than 5,000, more preferably 1,000 or more and 4,000 or less, and 1,000 or more. 3,000 or less is particularly preferred.
The weight average molecular weight of the oligomer in the present embodiment means the weight average molecular weight (Mw) in terms of standard polystyrene measured using GPC (gel permeation chromatography). The weight-average molecular weight of the oligomer in the present embodiment can be determined, for example, using gel permeation chromatography (for example, product number: HLC-8320 manufactured by Tosoh Corporation), column: two connections of G2500HXL and G-2500HXL, detector: RI, mobile phase: weight average molecular weight in terms of standard polystyrene analyzed under the conditions of tetrahydrofuran is used.

As described above, the concept of the oligomer in the present embodiment includes not only a single polymerizable compound but also a mixture of multiple types of polymerizable compounds. When a single polymerizable compound is used as the oligomer of the present embodiment, the oligomer having a weight-average molecular weight of 1,000 or more obtained under the above conditions for the compound alone may be used.
On the other hand, when the oligomer in the present embodiment is a mixture of multiple types of polymerizable compounds, multiple peaks are confirmed by GPC analysis under the above conditions. Thus, when the oligomer in this embodiment is a mixture, the weight-average molecular weight of the entire mixture obtained by integrating a plurality of peaks is regarded as the weight-average molecular weight of the oligomer. That is, even if the oligomer in the present embodiment is a mixture and contains a monomer having a weight average molecular weight of less than 1000 when measured alone, the weight average molecular weight of the entire mixture obtained by integrating a plurality of peaks is 1000. The above corresponds to "an oligomer having a weight average molecular weight of 1000 or more" in the present embodiment. The weight average molecular weight of the entire mixture can be obtained by using a commercially available GPC device. The weight average molecular weight (converted to standard polystyrene) of the entire mixture can be calculated by using the total value of each peak for each of the height [mV], area [mV*sec], and area % [%].

On the other hand, the oligomer of the present embodiment does not include a polymer having a weight average molecular weight of 5,000 or more when measured alone. Therefore, when the above-mentioned mixture contains a compound (that is, a polymer) having a weight average molecular weight of 5,000 or more, the molecular weight obtained by GPC analysis after separating all the polymers from the mixture is It is the weight average molecular weight of the mixture (oligomer).
The means for separating the oligomer and the polymer in the present embodiment is not particularly limited, and known means can be appropriately selected. For example, by mixing the resin composition with a low-polarity solvent (for example, normal hexane), the polymer in the resin composition can be precipitated, whereby the polymer component and the oligomer component can be separated.
At this time, even if the GPC analysis is performed while the photopolymerization initiator or the like is contained in the oligomer component, there is no particular effect on the weight average molecular weight of the obtained oligomer due to the relation of the molecular weight if it is a normal photopolymerization initiator.

The oligomer having a molecular weight of 1000 or more is not particularly limited, and examples thereof include tripentaerythritol acrylate, mono- and dipentaerythritol acrylates, a mixture of polypentaerythritol acrylate, (meth)acrylate having a hydroxyl group and polyfunctional isocyanate. can be used.

Examples of (meth)acrylates having a hydroxyl group include 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, trimethylolpropane di(meth)acrylate, pentaerythritol tri(meth)acrylate, and ditrimethylol. Propane tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol ethylene oxide-modified penta(meth)acrylate, dipentaerythritol propylene oxide-modified penta(meth)acrylate, dipentaerythritol caprocalactone-modified penta(meth)acrylate ) acrylate, glycerol dimethacrylate, glycerol acrylate methacrylate, 2-hydroxy-3-acryloylpropyl methacrylate, a reaction product of an epoxy group-containing compound and carboxy (meth) acrylate, hydroxyl group-containing polyol polyacrylate, and the like.

Examples of the polyfunctional isocyanate include tolylene diisocyanate, hexamethylene diisocyanate, diphenylmethylene diisocyanate, isophorone diisocyanate, and polyisocyanate composed of hexamethylene diisocyanate and modified trimethylolpropane.

Further, an oligomer obtained by combining a (meth)acrylate having a hydroxyl group and an isocyanate monomer as described above can also be used as the oligomer in the present embodiment. Examples of the isocyanate monomer include 2-(meth)acryloyloxyethyl isocyanate and 1,1-(bisacryloyloxymethyl)ethyl isocyanate.

The content of the oligomer in the resin composition of the present embodiment is not particularly limited, and can be appropriately determined based on the O/P ratio described later. From a viewpoint, it is preferably 20 to 60% by mass, more preferably 25 to 55% by mass, and particularly preferably 30 to 50% by mass, based on the total solid content in the composition.

(O/P ratio)
In the resin composition of the present embodiment, the mass ratio of the alkali-soluble resin [P] to the oligomer [O] [O/P ratio=oligomer content (g)/alkali-soluble resin content (g)] is , from 0.4 to 1.0. If the O/P ratio is less than 0.4, the recovery rate of the resulting photospacer is lowered. Further, when the O/P ratio exceeds 1.0, the height uniformity of the obtained photospacer is deteriorated, and it is impossible to sufficiently suppress lens unevenness. Although the O/P ratio of the resin composition is not particularly limited, it is preferably 0.5 to 1.0 from the viewpoint of the uniformity of the height of the photospacer and the recovery rate.

The O/P ratio of the resin composition can be adjusted by appropriately changing the charging amount of the alkali-soluble resin and oligomer. In addition, the method for measuring the O / P ratio of the resin composition is not particularly limited, but it is measured by separating the polymer component (alkali-soluble resin) and the monomer component contained in the resin composition by a known means. can do.
For example, by precipitating the polymer component with a low-polarity solvent (e.g., normal hexane), separating the oligomer (including the photopolymerization initiator) component, and then determining the mass of each component excluding the solvent, the resin The O/P ratio of the composition can be determined. At this time, if the content of oligomers, photoinitiators and other additives can be specified by gas chromatography mass spectrometry (GCMS) or liquid chromatography mass spectrometry (LCMS), gas chromatography (GC), liquid chromatography A highly accurate O/P ratio result can be obtained by quantitative analysis such as (LC).

(Photoinitiator)
The resin composition in this embodiment can contain a photopolymerization initiator. Although not particularly limited, as the photopolymerization initiator in the present embodiment, one having an absorption wavelength in the i-line (365 nm) can be preferably used.

Examples of photopolymerization initiators include, but are not limited to, acetophenone, 2,2′-diethoxyacetophenone, p-dimethylacetophenone, p-dimethylaminopropiophenone, dichloroacetophenone, trichloroacetophenone, p- Acetophenones such as tert-butylacetophenone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one, 2-dimethylamino-2-(4-methylbenzyl)-1-( α-aminoketone photopolymerization initiators such as 4-morpholin-4-yl-phenyl)-butan-1-one, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one , 1,2-octanedione 1-[4-(phenylthio)-2-(O-benzoyloxime)], ethanone-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3 -yl]-1-(O-acetyloxime), 1-[9-ethyl-6-benzoyl-9. H. -carbazol-3-yl]-octan-1-one oxime-O-acetate, 1-[9-ethyl-6-(2-methylbenzoyl)-9. H. -carbazol-3-yl]-ethan-1-one oxime-O-benzoate, 1-[9-n-butyl-6-(2-ethylbenzoyl)-9. H. -carbazol-3-yl]-ethan-1-one oxime-O-benzoate, ethanone-1-[9-ethyl-6-(2-methyl-4-tetrahydrofuranylbenzoyl)-9. H. -carbazol-3-yl]-1-(O-acetyloxime), ethanone-1-[9-ethyl-6-(2-methyl-4-tetrahydropyranylbenzoyl)-9. H. -carbazol-3-yl]-1-(O-acetyloxime), ethanone-1-[9-ethyl-6-(2-methyl-5-tetrahydrofuranylbenzoyl)-9. H. -carbazol-3-yl]-1-(O-acetyloxime), ethanone-1-[9-ethyl-6-{2-methyl-4-(2,2-dimethyl-1,3-dioxolanyl)methoxybenzoyl }-9. H. -Carbazol-3-yl]-1-(O-acetyloxime) and other oxime ester photopolymerization initiators, benzophenone, 2-chlorobenzophenone, p,p'-bisdimethylaminobenzophenone and other benzophenones; benzyl, Benzoin ethers such as benzoin, benzoin methyl ether, benzoin isopropyl ether, and benzoin isobutyl ether; benzyl dimethyl ketal, thioxanthone, 2-chlorothioxanthone, 2,4-diethylthioxanthone, 2-methylthioxanthone, 2-isopropyl sulfur compounds such as thioxanthone; anthraquinones such as 2-ethylanthraquinone, octamethylanthraquinone, 1,2-benzanthraquinone and 2,3-diphenylanthraquinone; 2,4-trichloromethyl-(4′-methoxyphenyl)- 6-triazine, 2,4-trichloromethyl-(4′-methoxynaphthyl)-6-triazine, 2,4-trichloromethyl-(piperonyl)-6-triazine, 2,4-trichloromethyl-(4′-methoxy styryl)-6-triazine and other triazines; azobisisobutyronitrile, benzoyl peroxide, cumene peroxide and other organic peroxides, 2-mercaptobenzimidazole, 2-mercaptobenzoxazole, 2-mercaptobenzothiazole, etc. and the like. One of these photopolymerization initiators may be used alone, or two or more thereof may be used in combination.

The content of the photopolymerization initiator in the resin composition of the present embodiment is not particularly limited. 0% by mass is preferred, 0.5 to 7.5% by mass is more preferred, and 1.0 to 5.0% by mass is particularly preferred.

(others)
The resin composition of the present embodiment may contain, for example, a photopolymerization initiation aid, fine particles of 100 nm or less, and the like, as long as the effects of the resin composition of the present embodiment are not impaired.

The photopolymerization initiation aid is a compound that does not function as a photopolymerization initiator by itself, but increases the ability of the photopolymerization initiator when used in combination with the photopolymerization initiator. Examples of photopolymerization initiation aids include tertiary amines such as triethanolamine, which are effective when used in combination with benzophenone.

Addition of fine particles of 100 nm or less can improve the elastic recovery rate of the cured product of the resin composition of the present embodiment. Fine particles of 100 nm or less are not particularly limited, but examples thereof include Al ₂ O ₃ , TiO ₂ , Fe ₂ O ₃ , ZnO, CeO ₂ , Y ₂ O ₃ , Mn ₃ O ₄ and SiO ₂ . Also, the shape of the fine particles is not particularly limited, but examples include spherical, spherical, and polyhedral shapes.

(Preparation of resin composition)
The resin composition of the present embodiment contains, in addition to the components such as the above-described alkali-soluble resin, oligomer, and photopolymerization initiator, if necessary, a solvent, a leveling agent, a chain transfer agent, a polymerization inhibitor, a viscosity modifier, and the like. It can be prepared by adding and mixing.

-solvent-
As the solvent, a known solvent used in photosensitive resin compositions can be appropriately selected and used. Examples of solvents include, but are not limited to, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, ethyl acetate, butyl acetate, ethyl lactate, γ-butyrolactone, propylene glycol monomethyl ether acetate (PGMAc ), esters such as propylene glycol monoethyl ether acetate and methyl-3-methoxypropionate, and ethers such as polyoxyethylene lauryl ether, ethylene glycol monomethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether and diethylene glycol methyl ethyl ether. , aromatic hydrocarbons such as benzene, toluene and xylene, and amides such as dimethylformamide, dimethylacetamide and N-methylpyrrolidone.

<<Method of forming a photospacer>>
A photospacer using the resin composition of the present embodiment can be formed by forming a coating film containing the resin composition on a substrate, and exposing and developing the coating film.
The photospacer determines the gap of the liquid crystal cell when the substrates are bonded together, such as the color filter substrate and the TFT substrate, and plays an important role in the display quality. The height uniformity of the photospacers is preferably high. For example, the difference in height (maximum height - minimum height) is preferably 0.03 μm or less, particularly preferably 0.02 μm or less. . The height, shape, size, density, etc. of the photospacer can be appropriately determined according to the design of the liquid crystal display device or the like used.

As described above, a photospacer can be formed by exposing and developing the resin composition of the present embodiment by photolithography. The resin composition of the present embodiment is suitable for a photospacer forming method employing a projection exposure (lens scanning) method using a multi-lens system as an exposure method.

Water, an organic solvent, an alkaline aqueous solution, or the like can be appropriately used for development when forming the photospacer. Considering the load on the environment, etc., it is preferable to use an alkaline aqueous solution. Examples of the alkaline aqueous solution include aqueous solutions of inorganic salts such as sodium hydroxide, potassium hydroxide, sodium carbonate and potassium carbonate, and aqueous solutions of organic salts such as hydroxytetramethylammonium and hydroxytetraethylammonium.

《Substrate with photospacer》
A photospacer can be formed on a substrate by the method of forming a photospacer using the resin composition of the present embodiment. The substrate with photospacers of the present embodiment includes a substrate, an alkali-soluble resin and an oligomer having a weight average molecular weight of 1000 or more provided on the substrate, and the alkali-soluble resin [P] and the oligomer [O] are and a photospacer obtained by curing a photosensitive resin composition having a mass ratio [O/P ratio] of 0.4 to 1.0. Examples of the substrate include a transparent substrate for color filters, a TFT substrate provided with TFT elements, and the like. As the transparent substrate, for example, a glass, a plastic plate, a film, or the like can be used. Further, alkali-free glass or the like may be used in consideration of transparency, chemical resistance, low coefficient of thermal expansion, high-temperature dimensional accuracy, and the like.

《Color filter》
A photospacer formed from the resin composition of the present embodiment can be suitably used for color filters. The color filter of the present embodiment comprises a substrate, a colored layer provided on the substrate, an alkali-soluble resin provided on the colored layer, and an oligomer having a weight average molecular weight of 1000 or more, and the alkali-soluble resin [ A photospacer obtained by curing a photosensitive resin composition having a mass ratio [O/P ratio] between the oligomer [O] and the oligomer [O] of 0.4 to 1.0. The transparent substrate described above can be used as the substrate. In addition, for example, ITO, which becomes a transparent common electrode, can be vapor-deposited on the color filter.

Examples of the colored layer include a black matrix layer, a red layer, a green layer, a blue layer, and the like. Each colored layer is provided on a transparent substrate. The black matrix layer can be provided, for example, in a striped or grid pattern between pixels of each color or outside the formation region of the colored layer for the purpose of preventing deterioration of contrast due to light leakage. Examples of the method for forming the black matrix layer include a method of patterning a multi-layer deposited thin film of chromium and chromium oxide, and an ordinary photolithography method using a resin BM resist in which a light-shielding pigment such as carbon black is dispersed. . Also, the red layer, the green layer, and the blue layer can be arranged in order for each color, for example, in a dot pattern or a stripe pattern, depending on the shape of the black matrix layer.

The photospacers are preferably formed at predetermined positions on the black matrix layer so as not to impair the definition, color development and brightness of the liquid crystal display device. For example, by arranging a photospacer having a rectangular cross-sectional shape on the black matrix layer, it is possible to produce a color filter capable of producing a liquid crystal display device with high definition, excellent color development, and high brightness.

Hereinafter, the present invention will be described more specifically using examples and comparative examples. The present invention is by no means limited by the following examples.

[Synthesis Example 1]
(Production of acrylic resin (P-1))
100 g of glycidyl methacrylate and 150 g of propylene glycol monomethyl ether acetate were placed in a glass flask equipped with a heating/cooling/stirring device, a reflux condenser and a nitrogen inlet tube. After the gas phase in the system was replaced with nitrogen, 8.7 g of 2,2′-azobis(2,4-dimethylvaleronitrile) was added, heated to 80° C., and reacted at the same temperature for 8 hours.
35 g of acrylic anhydride, 43 g of methacrylic anhydride, 15 g of acrylic acid, 2 g of tetrabutylammonium chloride, 0.3 g of hydroquinone, and 177 g of propylene glycol monomethyl ether acetate were further added to the obtained solution, and the mixture was heated at 70° C. for 12 hours while blowing air. reacted over time. After that, 14 g of succinic anhydride was further added to the solution and reacted at 70° C. for 6 hours to obtain a 40 mass % solution of the desired polymer (acrylic resin (P-1) below).

Acrylic resin (P-1) [X: Y: Z = 40: 40: 20]

The acrylic resin (P-1) had a double bond equivalent of 157 and an acid value of 38 in terms of solid content. The weight average molecular weight (Mw) by GPC was 22,000.
The molecular weight was measured by gel permeation chromatography (product number: HLC-8120, column: G-5000HXL and G-3000HXL, detector: RI, mobile phase: tetrahydrofuran, manufactured by Tosoh Corporation). rice field.

[Synthesis Example 2]
(Production of acrylic resin (P-2))
100 g of glycidyl methacrylate and 150 g of propylene glycol monomethyl ether acetate were placed in a glass flask equipped with a heating/cooling/stirring device, a reflux condenser and a nitrogen inlet tube. After the gas phase in the system was replaced with nitrogen, 8.7 g of 2,2'-azobis(2,4-dimethylvaleronitrile) was added, heated to 80°C, and reacted at the same temperature for 8 hours.
Further, 51 g of acrylic acid, 2 g of tetrabutylammonium chloride, 0.3 g of hydroquinone, and 245 g of propylene glycol monomethyl ether acetate were added to the obtained solution, and the mixture was reacted at 100° C. for 12 hours while blowing air. After the reaction, 87 g of 2-methacryloyloxyethyl isocyanate (manufactured by Showa Denko K.K., product name: Karenz MOI) was added and reacted at 70° C. for 10 hours. After that, 14 g of succinic anhydride was further added to the solution and reacted at 70° C. for 6 hours to obtain a 40 mass % solution of the desired polymer (acrylic resin (P-2) below) below.

Acrylic resin (P-2) [X:Y=80:20]

The acrylic resin (P-2) had a double bond equivalent of 199 and an acid value of 31 in terms of solid content. The weight average molecular weight (Mw) by GPC was 28,000.

[Synthesis Example 3]
(Production of acrylic resin (P-3))
100 g of glycidyl methacrylate and 150 g of propylene glycol monomethyl ether acetate were placed in a glass flask equipped with a heating/cooling/stirring device, a reflux condenser and a nitrogen inlet tube. After the gas phase in the system was replaced with nitrogen, 8.7 g of 2,2'-azobis(2,4-dimethylvaleronitrile) was added, heated to 80°C, and reacted at the same temperature for 8 hours.
51 g of acrylic acid, 2 g of tetrabutylammonium chloride, 0.3 g of hydroquinone, and 165 g of propylene glycol monomethyl ether acetate were added to the obtained solution, and the mixture was reacted at 100° C. for 12 hours while blowing air. After the reaction, 8.7 g of 2-methacryloyloxyethyl isocyanate (manufactured by Showa Denko KK, product name: Karenz MOI) was added and reacted at 70° C. for 10 hours. After that, 50 g of succinic anhydride was further added to the solution and reacted at 70° C. for 6 hours to obtain a 40 mass % solution of the desired polymer (P-3).

Acrylic resin (P-3) [X:Y=10:90]

The acrylic resin (P-3) had a double bond equivalent of 275 and an acid value of 134 in terms of solid content. The weight average molecular weight (Mw) by GPC was 24,000.

[Synthesis Example 4]
(Production of oligomer (O-1))
100 g of dipentaerythritol hexaacrylate (manufactured by Nippon Kayaku Co., Ltd., product name: KAYARAD DPHA) and toluene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd.) were added to a glass flask equipped with a heating and cooling device, a stirring device, and a reflux condenser. , product name: Coronate T-100) was added and reacted at 60° C. for 8 hours while blowing air.

IR analysis was conducted after 8 hours, and it was confirmed that the 2270 cm ^-1 peak of the isocyanate group had disappeared. The weight average molecular weight (Mw) of the obtained oligomer (O-1) by GPC was 1,640.

The molecular weight was measured by gel permeation chromatography (manufactured by Tosoh Corporation, product number: HLC-8320, column: two connections of G2500HXL and G-2500HXL, detector: RI, mobile phase: tetrahydrofuran). was converted to standard polystyrene, and the overall weight-average molecular weight (Mw) was obtained by integrating multiple peaks.

[Synthesis Example 5]
(Production of oligomer (O-2))
100 g of dipentaerythritol hexaacrylate (manufactured by Nippon Kayaku Co., Ltd., product name: KAYARAD DPHA), isophorone diisocyanate (manufactured by Evonik Japan Ltd., 8.5 g of VESTANAT IPDI (product name) was added and reacted at 60° C. for 8 hours while blowing air.

IR analysis was conducted after 8 hours, and it was confirmed that the 2270 cm ^-1 peak of the isocyanate group had disappeared. The weight average molecular weight (Mw) of the obtained oligomer (O-2) by GPC was 1,680.

(other oligomers)
A mixture of tripentaerythritol acrylate, mono- and dipentaerythritol acrylates, and polypentaerythritol acrylate (manufactured by Osaka Organic Chemical Co., Ltd., product name: V#802) was measured by GPC under the same conditions as in Synthesis Example 4. By the way, the weight average molecular weight (Mw) was 1,059.
Similarly, a mixture of dipentaerythritol hexa and pentaacrylate (manufactured by Nippon Kayaku Co., Ltd., product name: KAYARAD DPHA) was measured by GPC and found to have a weight average molecular weight (Mw) of 826.

[Example 1]
(Preparation of photosensitive resin composition for photospacer)
According to the composition shown in the table below, acrylic resin (P-1) 40.0 g, oligomer (O-1) 8.0 g, photopolymerization initiator (manufactured by Ciba Specialty Chemicals, product name: Irgacure OXE-01)1. 0 g and 51.0 g of propylene glycol monomethyl ether acetate (solvent: PGMAc) were mixed under light shielding to prepare a 25 mass % solution of a photosensitive resin composition for photospacers.

[Examples 2 to 8, Comparative Example]
In Examples 2 to 8 and each Comparative Example, a 25 mass % solution of a photosensitive resin composition for photospacers was prepared in the same manner as in Example 1 except that the composition was changed according to the table below.

[Measurement of recovery rate]
For each example and comparative example, a photospacer resin composition was applied onto each glass substrate of 10 cm×10 cm square 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 exposed to light from an ultra-high pressure mercury lamp 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. Only the i-line 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 set to 50 μm for exposure.

After that, alkaline development was carried out using a 0.05% KOH aqueous solution. Then, after washing with water, post-baking was performed at 230° C. for 30 minutes to form a photospacer. As the photospacer, a columnar photospacer having a height of 4 μm and an upper base diameter of 10 μm was selected to measure the recovery rate.

The recovery rate of the obtained photospacer was measured. Measurement was performed using a microhardness tester (manufactured by Fisher Instruments, product name: FISCHERSCOPE HM-2000) on the obtained photospacer (height 4 μm) with a flat indenter with a diameter of 50 μm to determine the loading rate and release. Both loading speeds are 2.0 mN / sec, load is applied to 60 mN, held for 5 seconds, then unloaded to 0 mN, held for 5 seconds, load during loading - deformation curve, and unloading A load-deformation curve was created. Then, the recovery rate was calculated by the following formula, where L1 is the amount of deformation at a load of 60 mN when loaded, and L2 is the amount of deformation at a load of 0 mN when unloaded.
Recovery rate (%) = (L1-L2) x 100/L1

The results are shown in the table below. It should be noted that the recovery rate is preferably 75% or more.

[Confirmation of lens unevenness]
For each example and comparative example, a photospacer resin composition was applied onto a substrate 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 irradiated with 100 mJ/cm ² of only the i-line through a plurality of photospacer forming masks having openings with a diameter of 8 μm in a projection exposure method using a multi-lens scanner exposure machine. irradiated. After that, alkaline development was carried out using a 0.05% KOH aqueous solution. Then, after washing with water, post-baking was performed at 230° C. for 30 minutes to form a photospacer with a height of 4 μm.

Variation in height of 40 photospacers at regular intervals (maximum height - minimum height ) was measured. The results are shown in the table below. The variation in the height of the photospacer is preferably 0.02 μm or less.

As is clear from the table, all of the photospacers produced using the photospacer resin compositions of Examples had a restoration rate of 75% or more, and even when a multi-lens scanner exposure machine was used, photo The spacer height variation (lens unevenness) was excellent at 0.02 μm or less.
On the other hand, Comparative Examples 1 and 2 using DPHA (weight average molecular weight less than 1000), which does not correspond to the oligomer in the present invention, were obtained even when the O/P ratio was within the range of 0.5 to 1.0. The lens unevenness of the photospacer was 0.03 μm or more, which was inferior to the example.
In Comparative Example 3, in which the O/P ratio was less than 0.5 even though the oligomer of the present invention was used, the recovery rate of the obtained photospacer was low.
Furthermore, in Comparative Example 4 in which the O/P ratio exceeded 1.0 even though the oligomer of the present invention was used, the lens unevenness of the photospacer was inferior at 0.04 μm.

The disclosure of Japanese Patent Application No. 2017-184973 filed on September 26, 2017 is incorporated herein by reference in its entirety.
In addition, all publications, patent applications and technical standards mentioned in the specification shall be referred to to the same extent as if each individual publication, patent application or technical standard were specifically and individually noted to be incorporated by reference. , incorporated herein by reference.

Claims (9)

An alkali-soluble resin, an oligomer having a weight average molecular weight of 1000 or more and less than 5000, and a photopolymerization initiator ,
The mass ratio [O/P ratio] between the alkali-soluble resin [P] and the oligomer [O] is 0.4 to 1.0,
The photosensitive resin composition for forming a photospacer, wherein the alkali-soluble resin has a double bond equivalent of 100-270. 2. The photosensitive resin composition for forming a photospacer according to claim 1, wherein the alkali-soluble resin has a weight average molecular weight of 5,000 to 100,000. 3. The photosensitive resin composition for forming a photospacer according to claim 1, wherein the alkali-soluble resin is an acrylic resin. A photospacer is formed by forming a coating film containing the photosensitive resin composition for forming a photospacer according to any one of claims 1 to 3 on a substrate, and exposing and developing the coating film to form a photospacer. Forming method. 5. The method of forming a photospacer according to claim 4 , wherein the exposure is projection exposure. a substrate;
A photospacer provided on the substrate and obtained by curing the photosensitive resin composition for forming a photospacer according to any one of claims 1 to 3 ;
A substrate with a photospacer. a substrate;
a colored layer provided on the substrate;
A photospacer provided on the colored layer and obtained by curing the photosensitive resin composition for forming a photospacer according to any one of claims 1 to 3 ;
Color filters with 8. A color filter according to claim 7 , wherein said colored layer comprises a black matrix layer. 9. The color filter of claim 8 , wherein said photospacer is provided on said black matrix layer.