JP2020076016A - Copolymer, and resin composition containing the copolymer - Google Patents

Abstract

To provide an acrylic resin having excellent low refraction index while having photosensitivity exhibiting photocurability.SOLUTION: There is provided a copolymer (A) obtained by reacting a reaction product by polymerizing a polymerizable monomer (a-1A) having a bridging cyclic hydrocarbon group having 10 to 20 carbon atoms and/or a polymerizable monomer (a-1B) represented by the following chemical formula (1), a fluorine-containing (meth)acrylate (a-2) represented by the following chemical formula (2), and (meth)acrylate (a-3) having an epoxy group, with unsaturated carboxylic acid (b-1). In the formula (1), X and Y represent a hydrogen atom, a hydrocarbon group having 1 to 4 carbon atoms. In the formula (2), Z each independently represents a hydrogen atom, a fluorine atom, a CFgroup, a CFgroup, a CFgroup, or a hydroxy group, n is an integer of 0 to 12. In the formula (2), at least 3 or more fluorine atoms are contained.SELECTED DRAWING: None

Description

  The present invention relates to a copolymer (A), a resin composition and a photosensitive resin composition containing the copolymer (A), and a resist.

  In recent years, from the viewpoint of resource saving and energy saving, photosensitive resin compositions curable by active energy rays such as ultraviolet rays and electron rays have been widely used in the fields of various coatings, printing, paints, adhesives and the like. Also in the field of electronic materials such as printed wiring boards, photosensitive resin compositions curable by active energy rays can be used as solder resists, color filters, black matrices, black column spacers, photo spacers, protective film resists, etc. It is used. Furthermore, the required properties for a curable photosensitive resin composition have become more diverse and sophisticated, such as short-time curability in consideration of productivity and low-temperature curability that suppresses thermal damage to applied members.

  Above all, low reflectivity of electronic material members is regarded as important in order to make various devices highly functional, and in recent years, development of members with the theme of low reflectivity has been earnestly studied. For example, in microlenses used in digital cameras, smartphones, etc., in order to realize a high-quality image with little noise by significantly suppressing the reflected light from the concave portions between the lenses and improving the S / N ratio. There is an increasing demand for coating low reflectance layers along the surface of microlenses. In addition, in an image display device such as a liquid crystal display or an organic EL display, when external light such as sunlight or a fluorescent lamp is reflected, the external light diffuses after reaching the inside of the substrate of the image display device and the visibility of the screen deteriorates. . Therefore, for the purpose of improving visibility, various members such as a transparent substrate, a color filter, a black matrix, a column spacer, and a protective film, which constitute the image display device substrate, have a low reflectance to minimize the reflection of external light. There is an increasing demand for low-reflection displays to suppress.

  In order to meet these demands, a photosensitive resin composition used as a resist for coating the surface of a microlens, and a photosensitive resin composition used as a resist for producing a member constituting an image display device substrate. There is a demand for lower reflectance of the object, which means that lower reflectance of the resin itself constituting these photosensitive resin compositions is required. In addition, as a matter of course, these photosensitive resin compositions and the resins constituting them are required to have properties such as high thermal decomposition resistance, thermal yellowing resistance, and solvent resistance, which are conventionally required for resists. Has been.

  As shown in the Fresnel's equation, there is a positive correlation between the reflectance and the refractive index. Therefore, as a method for realizing the lower reflectance of the resin constituting the photosensitive resin composition, the lower refractive index is used. It is effective to introduce into the resin an atomic group indicating One of the most effective methods is to introduce a fluorine atom. Above all, an acrylic resin obtained by polymerizing a fluorine-containing (meth) acrylate is particularly noted as a fluorine atom-introduced resin that can be provided simply and efficiently. However, the fluorine atom-introduced resin has poor solubility, is poorly compatible with other photosensitive resin compositions, and forms a bead on the substrate, often causing a problem that the cured film cannot be coated smoothly.

  Therefore, as shown in Patent Documents 1 and 2, by introducing a fluorine atom introducing another monomer group and a fluorine-containing (meth) acrylate, the solubility is improved and smooth coatability of the cured film is realized. A resin can be provided.

JP 2007-119572 A JP, 2013-6928, A

However, the resin of the precedent has a low degree of fluorine substitution in the fluorine-containing (meth) acrylate and a low composition ratio of the fluorine-containing (meth) acrylate in all the monomers, so that it is possible to provide a satisfactory low refractive index acrylic resin. Is insufficient. Furthermore, the resin of the preceding example is not a photosensitive resin that is curable by active energy rays such as ultraviolet rays and electron beams, but exhibits photocurability by blending with other photosensitive resins and additives. For the purpose of improving productivity, a photosensitive resin composition that exhibits photocurability with a single liquid is in high demand, but a photosensitive acrylic resin having a satisfactory low refractive index has not been provided yet.
The present invention has been made to solve the above problems, and provides an acrylic resin having an excellent low refractive index while having photosensitivity to exhibit photocurability, and by using the resin, a microlens is provided. It is an object of the present invention to provide a photosensitive resin composition used for a resist that contributes to low reflection of all electronic material members such as an image display device.

That is, the present invention is represented by the following [1] to [8].

（式（１）中のＸおよびＹは、それぞれ独立して、水素原子、直鎖または分岐していてもよい炭素数１〜４の炭化水素基を示し、Ｒ１およびＲ２はそれぞれ独立して水素原子、カルボキシ基または置換基を有していてもよい炭素数１〜２０の炭化水素基であって、Ｒ１およびＲ２を結ぶ環状構造をとっていてもよい。）

（式（２）中、Ｒ３は水素原子またはメチル基を表し、Ｌは−Ｏ−、−Ｏ−ＣＨ_２−ＣＨ（ＯＨ）−ＣＨ_２−、−Ｏ−ＮＨ−Ｃ（＝Ｏ）−ＣＨ_２−ＣＨ_２−のいずれかの鎖である。Ｚはそれぞれ独立して水素原子、フッ素原子、ＣＦ_３基、Ｃ_２Ｆ_５基、Ｃ_３Ｆ_７基またはヒドロキシ基を表し、ｎは０〜１２の整数である。ただし、式（２）中、少なくともフッ素原子を３以上含む。）
［２］ 屈折率が１．５０未満である、［１］に記載の共重合体（Ａ）。
［３］ 前記エポキシ基含有共重合体（Ｐ）のフッ素当量が１００ｇ／ｍｏｌ以下である、［１］又は［２］に記載の共重合体（Ａ）。
［４］ 前記炭素数１０〜２０の橋かけ環式炭化水素基を有する重合性モノマー（ａ−１Ａ）がジシクロペンテニル（メタ）アクリレート、ジシクロペンタニル（メタ）アクリレート、イソボルニル（メタ）アクリレート、及びアダマンチル（メタ）アクリレートからなる群から選ばれる少なくとも１種を含む、［１］〜［３］のいずれかに記載の共重合体（Ａ）。
［５］ ［１］〜［４］のいずれかに記載の共重合体（Ａ）と溶剤（Ｂ）とを含有する樹脂組成物。
［６］ 更に反応性希釈剤（Ｃ）を含有する［５］に記載の樹脂組成物。
［７］ 更に光重合開始剤（Ｄ）を含有する［６］に記載の感光性樹脂組成物。
［８］ ［７］に記載の感光性樹脂組成物を用いるレジスト。 [1] An unsaturated group-containing copolymer (A1) having a hydroxy group formed by ring-opening addition of an unsaturated carboxylic acid (b-1) to the epoxy group of the epoxy group-containing copolymer (P), and Unsaturated group formed by adding an ethylenically unsaturated group-containing reactive monomer (b-2) having a functional group that reacts with a hydroxy group to the hydroxy group of the unsaturated group-containing copolymer (A1) having a hydroxy group Containing copolymer (A2)
A copolymer (A) containing at least one selected from the group consisting of:
The epoxy group-containing copolymer (P) is
It is composed of a structural unit derived from a polymerizable monomer (a-1A) having a bridged cyclic hydrocarbon group having 10 to 20 carbon atoms and a structural unit derived from a polymerizable monomer (a-1B) represented by the following chemical formula (1). At least one selected from the group;
A structural unit derived from a fluorine-containing (meth) acrylate (a-2) represented by the following chemical formula (2),
A copolymer containing a structural unit derived from an epoxy group-containing (meth) acrylate (a-3),
The copolymer (A), which has an unsaturated group equivalent of 2500 g / mol or less.

(X and Y in the formula (1) each independently represent a hydrogen atom, a linear or branched hydrocarbon group having 1 to 4 carbon atoms, and R 1 and R 2 each independently represent hydrogen. (A hydrocarbon group having 1 to 20 carbon atoms, which may have an atom, a carboxy group or a substituent, and may have a cyclic structure connecting R1 and R2.)

(In the formula (2), R3 represents a hydrogen atom or a methyl group, L is _{-O -, - O-CH 2} -CH (OH) -CH 2 -, - O-NH-C (= O) -CH Z is any chain of _2- CH ₂ — Z is independently a hydrogen atom, a fluorine atom, a CF ₃ group, a C ₂ F ₅ group, a C ₃ F ₇ group or a hydroxy group, and n is 0 to 0. It is an integer of 12, provided that at least three fluorine atoms are included in the formula (2).
[2] The copolymer (A) according to [1], which has a refractive index of less than 1.50.
[3] The copolymer (A) according to [1] or [2], wherein the epoxy group-containing copolymer (P) has a fluorine equivalent of 100 g / mol or less.
[4] The polymerizable monomer (a-1A) having a bridged cyclic hydrocarbon group having 10 to 20 carbon atoms is dicyclopentenyl (meth) acrylate, dicyclopentanyl (meth) acrylate, isobornyl (meth) acrylate. And a copolymer (A) according to any one of [1] to [3], containing at least one selected from the group consisting of: and adamantyl (meth) acrylate.
[5] A resin composition containing the copolymer (A) according to any one of [1] to [4] and a solvent (B).
[6] The resin composition according to [5], which further contains a reactive diluent (C).
[7] The photosensitive resin composition according to [6], which further contains a photopolymerization initiator (D).
[8] A resist using the photosensitive resin composition according to [7].

According to the present invention, it is possible to provide an acrylic resin having an excellent low refractive index while exhibiting photocurability and photosensitivity. Further, the photosensitive resin composition of the present invention can be suitably used for a resist that contributes to low reflection of all electronic material members such as microlenses and image display devices.

  The present invention will be described in detail below.

[Copolymer (A)]
The copolymer (A) of the present invention is an unsaturated group-containing copolymer having a hydroxy group formed by ring-opening addition of the unsaturated carboxylic acid (b-1) to the epoxy group of the epoxy group-containing copolymer (P). Ethylenically unsaturated group-containing reactive monomer (b-2) having a functional group that reacts with a hydroxy group in the hydroxy group of the polymer (A1) and the unsaturated group-containing copolymer (A1) having the hydroxy group And at least one selected from the group consisting of the unsaturated group-containing copolymer (A2). The epoxy group-containing copolymer (P) is a structural unit derived from a polymerizable monomer (a-1A) having a bridged cyclic hydrocarbon group having 10 to 20 carbon atoms and a polymerizable monomer represented by the above chemical formula (1). At least one selected from the group consisting of structural units derived from (a-1B), a structural unit derived from the fluorine-containing (meth) acrylate (a-2) represented by the chemical formula (2), and an epoxy group-containing ( It is a copolymer containing a structural unit derived from (meth) acrylate (a-3). Further, the unsaturated group equivalent of the copolymer (A) of the present invention is 2500 g / mol or less. Here, the (meth) acrylate means one or more selected from methacrylate and acrylate.

[First embodiment]
The first embodiment of the copolymer (A) of the present invention has a hydroxy group formed by ring-opening addition of the unsaturated carboxylic acid (b-1) to the epoxy group of the epoxy group-containing copolymer (P). It contains an unsaturated group-containing copolymer (A1). The first embodiment of the copolymer (A) of the present invention is preferably an unsaturated group-containing copolymer (A1). The unsaturated group equivalent of the copolymer (A) of this embodiment is 2500 g / mol or less.

[Epoxy group-containing copolymer (P)]
The epoxy group-containing copolymer (P) according to the copolymer (A) of the present embodiment (hereinafter sometimes simply referred to as “copolymer (P)”) is a crosslinker having 10 to 20 carbon atoms. At least one selected from the group consisting of a polymerizable monomer (a-1A) having a cyclic hydrocarbon group and a polymerizable monomer (a-1B) represented by the following chemical formula (1), and the following chemical formula (2) It is a copolymer of monomers containing the fluorine-containing (meth) acrylate (a-2) shown and the epoxy group-containing (meth) acrylate (a-3). The fluorine equivalent of the epoxy group-containing copolymer (P) is preferably 100 g / mol or less, more preferably 30 to 100 g / mol, and further preferably 40 to 100 g / mol.

[Polymerizable Monomer (a-1A)]
The polymerizable monomer (a-1A) (hereinafter sometimes simply referred to as “monomer (a-1A)”) has a bridged cyclic hydrocarbon group having 10 to 20 carbon atoms. Here, the bridged cyclic hydrocarbon means one having a structure represented by the following formula (3) or (4) represented by adamantane and norbornane, and the bridged cyclic hydrocarbon group is , Refers to a group corresponding to the rest of the structure except for some hydrogen. Moreover, the polymerizable monomer (a-1A) does not include the later-described polymerizable monomer (a-1B).

(In the formula (3), A and B each represent a linear or branched alkylene group (including cyclic group), and R6 represents a hydrogen atom or a methyl group. Even if A and B are the same, They may be different, or the branches of A and B may be connected to form a ring.)

(In the formula (4), A ′, B ′, and L ′ each represent a linear or branched alkylene group (including cyclic group), and R7 represents a hydrogen atom or a methyl group. A ′ and B ′. , L ′ may be the same or different, and the branches of A ′, B ′ and L ′ may be connected to form a ring.)

  The monomer (a-1A) is preferably a (meth) acrylate having a bridged cyclic hydrocarbon group having 10 to 20 carbon atoms, and has a structure represented by adamantyl (meth) acrylate or the following formula (5) ( More preferred is (meth) acrylate.

(In formula (5), R8 to R10 each represent a hydrogen atom or a methyl group. R11 and R12 may be a hydrogen atom or a methyl group, or may be bonded to each other to form a saturated or unsaturated ring. The ring is preferably a 5-membered ring or a 6-membered ring. * Represents a bond linked to the (meth) acryloyloxy group.)

  Examples of the monomer (a-1A) include dicyclopentenyl (meth) acrylate, dicyclopentanyl (meth) acrylate, isobornyl (meth) acrylate, and adamantyl (meth) acrylate. These may be used alone or in combination of two or more.

[Polymerizable Monomer (a-1B)]
The polymerizable monomer (a-1B) (hereinafter sometimes simply referred to as “monomer (a-1B)”) is a monomer represented by the following general formula (1).

(In the formula, X and Y each independently represent a hydrogen atom, or a linear or branched hydrocarbon group having 1 to 4 carbon atoms, and R 1 and R 2 are each independently a hydrogen atom, a carboxy group, or It represents a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, and may form a cyclic structure in which R1 and R2 are linked.)

  The monomer (a-1B) is not particularly limited as long as it has the chemical structure represented by the general formula (1). In the general formula (1), examples of X and Y representing a linear or branched hydrocarbon group having 1 to 4 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, and an n-butyl group. , Isobutyl group, t-butyl group and the like. Further, examples of the substituent of the hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, which is represented by R1 and R2, include an alkoxy group and an aryl group. Examples of R1 and R2 include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, t-amyl group, stearyl group, lauryl group, 2-ethylhexyl group. A linear or branched alkyl group such as; cyclohexyl group, t-butylcyclohexyl group, dicyclopentadienyl group, tricyclodecanyl group, isobornyl group, adamantyl group, 2-methyl-2-adamantyl group, etc. Cyclic groups; alkyl groups substituted with alkoxy groups such as 1-methoxyethyl group and 1-ethoxyethyl group; alkyl groups substituted with aryl groups such as phenylaralkyl group.

Examples of the monomer (a-1B) having the chemical structure represented by the general formula (1) include norbornene (bicyclo [2.2.1] hept-2-ene) and 5-methylbicyclo [2.2.1]. ] Hept-2-ene, 5-ethylbicyclo [2.2.1] hept-2-ene, tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene, 8-methyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene, 8-ethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene, dicyclopentadiene, tricyclo [5.2.1.0 ^2,6 ] dec-8-ene, tricyclo [5.2.1.0 ^2,6 ] deca-3 -Ene, tricyclo [4.4.0.1 ^2,5 ] undec-3-ene, tricyclo [6.2.1.0 ^1,8 ] undec-9-ene, tricyclo [6.2.1.0] ^1,8 ] undec-4-ene, tetracyclo [4.4.0.1 ^2,5 . 1 ^{7, 10} . 0 ^1,6 ] dodeca-3-ene, 8-methyltetracyclo [4.4.0.1 ^2,5 . 1 ^{7, 10} . 0 ^1,6 ] dodeca-3-ene, 8-ethylidene tetracyclo [4.4.0.1 ^2,5 . 1 ^7,12 ] dodec-3-ene, 8-ethylidenetetracyclo [4.4.0.1 ^2,5 . 1 ^{7, 10} . 0 ^1,6 ] dodeca-3-ene, pentacyclo [6.5.1.1 ^3,6 . 0 ^2,7 . 0 ^9,13] pentadeca-4-ene, pentacyclo [7.4.0.1 ^2,5. 1 ^{9 and 12} . 0 ^8,13] pentadeca-3-ene, and the like. These may be used alone or in combination of two or more.

  Use of the monomer (a-1A) and / or the monomer (a-1B) contributes to smooth coatability of the cured film, high thermal decomposition resistance, and high heat yellowing. Further, it is possible to suppress the decrease in the solubility of the copolymer in the solvent due to the presence of fluorine. One of the monomer (a-1A) and the monomer (a-1B) may be used, or both may be used.

[Fluorine-containing (meth) acrylate (a-2)]
The fluorine-containing (meth) acrylate (a-2) (hereinafter sometimes simply referred to as "monomer (a-2)") is a fluorine-containing (meth) acrylate represented by the following chemical formula (2).

(In the formula (2), R3 represents a hydrogen atom or a methyl group, L is _{-O -, - CH 2 -CH (} OH) -CH 2 -O-, CH 2 -CH 2 -NH-C (= O ) —O—, each Z independently represents a hydrogen atom, a fluorine atom, a CF ₃ group, a C ₂ F ₅ group, a C ₃ F ₇ group or a hydroxy group, and n is 0 to 12 However, in the formula (2), at least three fluorine atoms are included.)

  The fluorine-containing (meth) acrylate (a-2) is not particularly limited as long as it is represented by the above formula (2). The use of the fluorine-containing (meth) acrylate (a-2) makes it possible to reduce the refractive index of the resin, but the effect becomes remarkable when the monomer contains 3 or more fluorine atoms. When n ≧ 13, further lowering of the refractive index can be expected, but there is a possibility that the hardness of the cured film may not be sufficiently exhibited, so that n is in the range of 0 to 12.

  As the fluorine-containing (meth) acrylate (a-2), a commercially available product may be used, or a reactive (meth) acrylic acid such as (meth) acrylic acid, glycidyl (meth) acrylate, or 2-isocyanatoethyl (meth) acrylate may be used. ) Acrylic acid derivative and fluoroalcohol may be prepared by self-condensing. As specific examples, 2,2,2-trifluoroethyl (meth) acrylate, 3,3,3-trifluoropropyl (meth) acrylate, 2,2,3,3-tetrafluoropropyl (meth) acrylate, 3 , 3,4,4-Tetrafluorobutyl (meth) acrylate, 2,2,3,3,3-pentafluoropropyl (meth) acrylate, 3,3,4,4,4-pentafluorobutyl (meth) acrylate 1H, 1H-perfluoro-n-butyl (meth) acrylate, 1H, 1H-perfluoro-n-pentyl (meth) acrylate, 1H, 1H-perfluoro-n-hexyl (meth) acrylate, 1H, 1H-perfluoro-n -Octyl (meth) acrylate, 1H, 1H-perfluoro-n-decyl (meth) acrylate, 1H, 1H-perfluoro-n-dodecyl (meth) acrylate, 1H, 1H-perfluoroisobutyl (meth) acrylate, 1H, 1H- Perfluoroisooctyl (meth) acrylate, 1H, 1H-perfluoroisododecyl (meth) acrylate, 1H, 1H, 5H-octafluoropentyl (meth) acrylate, 1H, 1H, 5H-perfluoropentyl (meth) acrylate, 1H, 1H , 6H-perfluorohexyl (meth) acrylate, 1H, 1H, 7H-perfluoroheptyl (meth) acrylate, 1H, 1H, 8H-perfluorooctyl (meth) acrylate, 1H, 1H, 9H-perfluorononyl (meth) acrylate, 1H , 1H, 10H-perfluorodecyl (meth) acrylate, 1H, 1H, 11H-perfluoroundecyl (meth) acrylate, 1H, 1H, 12H-perfluorododecyl (meth) acrylate, 2- (perfluoro-n-propyl) ethyl ( (Meth) acrylate, 2- (perfluoro-n-butyl) ethyl (meth) acrylate, 2- (perfluoro-n-hexyl) ethyl (meth) acrylate, 2- (perfluoro-n-octyl) ethyl (meth) acrylate, 2 -(Perfluoro-n-decyl) ethyl (meth) acrylate, 2- (perfluoroisobutyl) ethyl (meth) acrylate, 2- (perfluoroisooctyl) ethyl (meth) acrylate, 1H, 1H, 2H, 2H-nonafluorohexyl (Meth) acrylate, 1H, 1H, 2H, 2H-tridecafluorooctyl (meth) acrylate, 1H, 1H, 2H, 2H-heptadecafluorodecyl (meth) acrylate etc. are mentioned. These may be used alone or in combination of two or more.

[Epoxy group-containing (meth) acrylate (a-3)]
The epoxy group-containing (meth) acrylate (a-3) (hereinafter sometimes simply referred to as “monomer (a-3)”) is an epoxy group having a good reactivity with an acid group among cyclic ether skeletons. There is no particular limitation as long as it is a monomer having an ethylenically unsaturated group. Specific examples include glycidyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate glycidyl ether, and 3,4-epoxycyclohexylmethyl (meth) acrylate. In particular, glycidyl (meth) acrylate is preferable from the viewpoint of easy availability and good reactivity.

  The constitutional unit derived from the epoxy group-containing (meth) acrylate (a-3) and the unsaturated carboxylic acid (b-1) described below impart a photosensitive group that exhibits photocurability, and therefore, are one embodiment of the present invention. It is an essential constituent in the copolymer (A). By introducing a photosensitive group exhibiting photocurability, the cured film exhibits sufficient hardness and high solvent resistance. Further, it is possible to suppress the decrease in solubility of the copolymer in the solvent due to the presence of fluorine, a photosensitive resin composition obtained by mixing a fluororesin having no photocurability and another photocurable component In comparison, it is possible to provide a familiar photosensitive resin composition.

[Other polymerizable monomers (a-4)]
The epoxy group-containing copolymer (P) according to the copolymer (A) of one aspect of the present invention is at least one selected from the group consisting of the monomer (a-1A) and the monomer (a-1B). And other polymerizable monomer (a-4) other than the monomer (a-2) and the monomer (a-3) (hereinafter, may be simply referred to as “monomer (a-4)”). May be copolymerized. The other polymerizable monomer (a-4) is a copolymerizable monomer other than the above-mentioned monomers (a-1A), (a-1B), (a-2) and (a-3). This monomer (a-4) is generally a radically polymerizable compound having an ethylenically unsaturated group, and specific examples thereof include dienes such as butadiene; methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl. (Meth) acrylate, iso-propyl (meth) acrylate, n-butyl (meth) acrylate, sec-butyl (meth) acrylate, iso-butyl (meth) acrylate, tert-butyl (meth) acrylate, pentyl (meth) ) Acrylate, neopentyl (meth) acrylate, benzyl (meth) acrylate, isoamyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, dodecyl (meth) acrylate, cyclopentyl (meth) ) Acrylate, cyclohexyl (meth) acrylate, methylcyclohexyl (meth) acrylate, ethylcyclohexyl (meth) acrylate, rosin (meth) acrylate, allyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, triphenylmethyl (meth) acrylate (Meth) acrylic acid ester such as cumyl (meth) acrylate, 3- (N, N-dimethylamino) propyl (meth) acrylate, naphthalene (meth) acrylate, anthracene (meth) acrylate; (meth) acrylic acid amide , (Meth) acrylic acid N, N-dimethylamide, (meth) acrylic acid N, N-diethylamide, (meth) acrylic acid N, N-dipropylamide, (meth) acrylic acid N, N-di-iso- Propylamide, (meth) acrylic acid amide such as (meth) acrylic acid anthracenylamide; (meth) acrylic acid anilide, (meth) acryloylnitrile, acrolein, vinyl chloride, vinylidene chloride, vinyl fluoride, vinylidene fluoride, Vinyl compounds such as N-vinylpyrrolidone, vinylpyridine, vinyl acetate and vinyltoluene; styrene, α-, o-, m-, p-alkyl, nitro, cyano, amide derivatives of styrene; N-phenylmaleimide, N-cyclohexyl Maleimides such as maleimide, N-lauryl maleimide and N- (4-hydroxyphenyl) maleimide; unsaturated dicarboxylic acid diesters such as diethyl citracone, diethyl maleate, diethyl fumarate and diethyl itaconic acid. These may be used alone or in combination of two or more, if necessary.

[Ratio of structures derived from each monomer of the epoxy group-containing copolymer (P)]
In the copolymer (P) according to the present invention, the ratio of each monomer-derived structure is the value of the molar ratio of each polymerizable monomer added for the copolymerization reaction. The mixing ratio (molar ratio) of each monomer is not particularly limited, but the total of the monomer (a-1A) and the monomer (a-1B), the monomer (a-2), and the monomer (a-3) is 100 mol%. In this case, the total blending ratio of the monomer (a-1A) and the monomer (a-1B) is preferably 1 to 40 mol%, more preferably 2 to 20 mol%. When the mixing ratio of the monomer (a-1A) and the monomer (a-1B) is 1 mol% or more, desired thermal decomposition resistance, thermal yellowing resistance, and good solubility in a solvent can be obtained. On the other hand, when the blending ratio is 40 mol% or less, the blending ratio of the monomer (a-2) and the monomer (a-3) becomes sufficiently large, and the copolymer (A) having a desired refractive index and curability. Is obtained. Further, the blending ratio of the monomer (a-2) is preferably 20 to 90 mol%, more preferably 30 to 85 mol%. When the blending ratio of the monomer (a-2) is 20 mol% or more, the copolymer (A) having a sufficiently low refractive index can be obtained. When the compounding ratio of the monomer (a-2) is 90 mol% or less, the compounding ratio of the monomer (a-1A) and / or the monomer (a-1B) and the monomer (a-3) will be sufficiently high, and the desired ratio will be obtained. A copolymer (A) having thermal decomposition resistance, curability, and good solubility in a solvent can be obtained. The mixing ratio of the monomer (a-3) is preferably 9 to 70 mol%, more preferably 13 to 65 mol%. When the blending ratio of the monomer (a-3) is 9 mol% or more, sufficient curability can be exhibited when the photosensitive resin composition is prepared, and the fluororesin and other photocurable resin which are not photocurable It is possible to provide a photosensitive resin composition that is more familiar than a photosensitive resin composition in which a photocurable component is mixed. If the blending ratio of the monomer (a-3) is 70 mol% or less, the blending ratio of the monomer (a-1A) and / or the monomer (a-1B) and the monomer (a-2) will be sufficiently high, and the desired amount will be obtained. A copolymer (A) having thermal decomposition resistance and refractive index can be obtained.

[Copolymerization reaction (method for producing epoxy group-containing copolymer (P)]]
The epoxy group-containing copolymer (P) according to the present invention can be produced by using a copolymerization reaction. The copolymerization reaction carried out in the present invention can be carried out according to a radical polymerization method known in the art. For example, a monomer used for copolymerization may be dissolved in a solvent, a polymerization initiator may be added to the solution, and the reaction may be performed at 50 to 130 ° C. for 1 to 20 hours. Further, the monomer used for the copolymerization and the polymerization initiator may be added dropwise to the solvent adjusted to 50 to 130 ° C. for the reaction.

  The solvent that can be used in this copolymerization reaction is not particularly limited as long as it is inert to radical polymerization, and a commonly used organic solvent can be used. Specific examples include glycol ether solvents such as propylene glycol monomethyl ether and propylene glycol monomethyl ether acetate; aromatic solvents such as toluene and xylene; ester solvents such as ethyl acetate, isopropyl acetate and ethyl lactate. These may be used alone or in combination of two or more. Of these, glycol ether solvents are preferred.

  The amount of the solvent used in this copolymerization reaction is not particularly limited, but is generally 30 to 1000 parts by mass, preferably 50 to 800 parts by mass, when the total amount of the monomers used in the copolymerization is 100 parts by mass. In particular, when the amount of the solvent used is 1000 parts by mass or less, the decrease in the molecular weight of the copolymer (P) is suppressed by the chain transfer action, and the viscosity of the copolymer (P) is controlled within an appropriate range. be able to. Further, by using the solvent in an amount of 30 parts by mass or more, an abnormal polymerization reaction can be prevented, the polymerization reaction can be stably performed, and coloring and gelation of the copolymer (P) can be prevented. You can also

  The polymerization initiator that can be used in this copolymerization reaction is not particularly limited as long as it can initiate radical polymerization, and a commonly used organic peroxide catalyst or azo compound can be used. You can Specifically, azobisisobutyronitrile, azobisisovaleronitrile, 2,2'-azobis (2,4-dimethylvaleronitrile), azobis (2-methylpropionic acid) dimethyl, benzoyl peroxide, dicumyl. Peroxide, diisopropyl peroxide, di-t-butyl peroxide, t-butyl peroxybenzoate, t-hexyl peroxybenzoate, t-butyl peroxy-2-ethylhexanoate, t-hexyl peroxy-2- Examples thereof include ethyl hexanoate and 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate. These may be used alone or in combination of two or more, and it is desirable to select a radical polymerization initiator having an appropriate half-life according to the polymerization temperature.

  The amount of the polymerization initiator used in this copolymerization reaction is not particularly limited, but is generally 0.5 to 20 parts by mass, preferably 1.0 to 10 parts by mass when the total amount of the monomers used in the copolymerization is 100 parts by mass. 10 parts by mass.

  The fluorine equivalent of the epoxy group-containing copolymer (P) is the mass of the polymer per the number of moles of fluorine atom, and is a calculated value calculated based on the amount of the monomer used. When this value is 100 g / mol or less, the refractive index of the acrylic resin as an acrylic resin that exhibits photocurability by adding an unsaturated carboxylic acid (b-1) or an ethylenically unsaturated group-containing reactive monomer (b-2) It is possible to obtain the copolymer (A) of the present invention having a sufficiently low value. The lower this value is, the lower the refractive index of the copolymer (A) can be, but the solubility of the copolymer in a solvent is lowered, and the compatibility with other photosensitive resin compositions may be deteriorated. There is. Therefore, the fluorine equivalent is preferably 30 to 100 g / mol, more preferably 40 to 100 g / mol.

[Unsaturated group-containing copolymer (A1)]
The unsaturated group-containing copolymer (A1) is formed by ring-opening addition of the unsaturated carboxylic acid (b-1) to the epoxy group of the epoxy group-containing copolymer (P).

[Unsaturated carboxylic acid (b-1)]
The unsaturated carboxylic acid (b-1) (hereinafter sometimes simply referred to as "monomer (b-1)") includes, among acid groups, a carboxy group which has a high reactivity with an epoxy group and an ethylenic unsaturated group. There is no particular limitation as long as it is a monomer having a group. Specific examples of the monomer include (meth) acrylic acid, itaconic acid, crotonic acid, cinnamic acid, 2- (meth) acryloyloxyethylsuccinic acid, 2- (meth) acryloyloxyethylphthalic acid, 2- (meth) acryloyl. Examples thereof include oxyethylhexahydrophthalic acid. In particular, (meth) acrylic acid is preferable from the viewpoints of easy availability and good reactivity.

  The reaction ratio of the unsaturated carboxylic acid (b-1) is 100 mol% based on the total amount of the monomer (a-1A) and / or the monomer (a-1B), the monomer (a-2), and the monomer (a-3). In the case of, it is preferably 10 to 70 mol%, more preferably 15 to 65 mol%. When the blending ratio of the unsaturated carboxylic acid (b-1) is 10 mol% or more, sufficient curability can be exhibited in the photosensitive resin composition. Moreover, when it is 70 mol% or less, a sufficient mixing ratio of the monomer (a-1A) and / or the monomer (a-1B) and the monomer (a-2) is ensured, and desired thermal decomposition resistance and refractive index are obtained. The copolymer (A) having is obtained. Further, the ratio of the unsaturated carboxylic acid (b-1) to be added to the number of moles of the epoxy group contained in the epoxy group-containing copolymer (P) is preferably 90 to 100%, and more preferably Is 95 to 100%. When the addition ratio of the unsaturated carboxylic acid (b-1) is 90% or more, sufficient curability can be exhibited when the photosensitive resin composition is prepared, and the fluororesin and other materials having no photocurability can be obtained. It is possible to provide a photosensitive resin composition which is more familiar than the photosensitive resin composition in which the photo-curable component described above is mixed.

[Method for producing unsaturated group-containing copolymer (A1)]
The unsaturated group-containing copolymer (A1) according to the present invention is obtained by adding a polymerization inhibitor and a catalyst to a solution of the copolymer (P) having an epoxy group and then adding the unsaturated carboxylic acid (b-1). It can be produced by adding the compound and subjecting the epoxy group to a ring-opening addition reaction at 50 to 150 ° C., preferably 80 to 130 ° C.

  When the unsaturated carboxylic acid (b-1) is reacted, there is no particular problem even if the solvent used in the above-mentioned copolymerization reaction is contained. Therefore, the reaction is performed without removing the solvent after the copolymerization reaction is completed. It can be performed. Here, the polymerization inhibitor is added to prevent gelation due to polymerization of the introduced double bond. The type is not particularly limited, and specific examples thereof include hydroquinone, methylhydroquinone, hydroquinone monomethyl ether, dibutylhydroxytoluene and the like. The catalyst is also not particularly limited, but specifically, tertiary amines such as triethylamine, quaternary ammonium salts such as triethylbenzylammonium chloride, phosphorus compounds such as triphenylphosphine, organic metals such as chromium and tin. A compound etc. are mentioned.

[Second embodiment]
The second embodiment of the copolymer (A) of the present invention has a hydroxy group formed by ring-opening addition of the unsaturated carboxylic acid (b-1) to the epoxy group of the epoxy group-containing copolymer (P). Unsaturated group-containing copolymer obtained by adding an ethylenically unsaturated group-containing reactive monomer (b-2) having a functional group that reacts with a hydroxy group to the hydroxy group of the unsaturated group-containing copolymer (A1) (A2) is included. The second embodiment of the copolymer (A) of the present invention is preferably an unsaturated group-containing copolymer (A2). The unsaturated group equivalent of the copolymer (A) of this embodiment is 2500 g / mol or less. Since the unsaturated group-containing copolymer (A1) having a hydroxy group according to the second embodiment is the same as the unsaturated group-containing copolymer (A1) having a hydroxy group according to the first embodiment, description will be made. Is omitted.

[Unsaturated group-containing copolymer (A2)]
The unsaturated group-containing copolymer (A2) is an ethylenically unsaturated group-containing reactive monomer having a functional group having reactivity with the hydroxy group in the hydroxy group of the unsaturated group-containing copolymer (A1) ( b-2) is an unsaturated group-containing copolymer formed by addition. In the epoxy group-containing copolymer (P), the hydroxy group has an unsaturated carboxylic acid (b-1) ring-opened in the epoxy group of the constituent unit derived from the epoxy group-containing (meth) acrylate (a-3). It is a hydroxy group generated by addition.

[Ethylenically unsaturated group-containing reactive monomer (b-2)]
As the ethylenically unsaturated group-containing reactive monomer (b-2) (hereinafter sometimes simply referred to as "reactive monomer (b-2)" or "monomer (b-2)"), the above-mentioned unsaturated It is not particularly limited as long as it is a monomer having a functional group having a good reactivity with a hydroxy group of the group-containing copolymer (A1) and an ethylenically unsaturated group, but a monomer having an isocyanato group is preferable because of its good reactivity with a hydroxy group. It is particularly suitable. Specific examples include 2-isocyanatoethyl (meth) acrylate and 1,1- (bisacryloyloxymethyl) ethyl isocyanate.

  The reaction ratio of the ethylenically unsaturated group-containing reactive monomer (b-2) is the same as that of the monomer (a-1A) and / or the monomer (a-1B), the monomer (a-2), and the monomer (a-3). When the total is 100 mol%, it is preferably 5 to 65 mol%, more preferably 5 to 50 mol%. When the blending ratio of the ethylenically unsaturated group-containing reactive monomer (b-2) is 5 mol% or more, further curability can be exhibited when the photosensitive resin composition is prepared. When the blending ratio of the ethylenically unsaturated group-containing reactive monomer (b-2) is 65 mol% or less, the copolymer (A) having a desired refractive index can be obtained. The ratio of the ethylenically unsaturated group-containing reactive monomer (b-2) to the number of moles of the unsaturated carboxylic acid (b-1) included in the unsaturated group-containing copolymer (A1) is preferably It is 10 to 90%, and more preferably 30 to 70%. When the ratio of the ethylenically unsaturated group-containing reactive monomer (b-2) is 10% or more, further curability can be exhibited in the photosensitive resin composition. When it is 90% or less, the unreacted product of the ethylenically unsaturated group-containing reactive monomer (b-2) does not remain and the desired copolymer (A) is obtained.

[Method for producing unsaturated group-containing copolymer (A2)]
The unsaturated group-containing copolymer (A2) is produced by producing the unsaturated group-containing copolymer (A1), then adding the ethylenically unsaturated group-containing reactive monomer (b-2), and heating at 50 to 150 ° C. Preferably, it can be produced by reacting the hydroxy group with the monomer (b-2) under the condition of 80 to 130 ° C.

  When reacting the ethylenically unsaturated group-containing reactive monomer (b-2), there is no particular problem even if the solvent used in the above copolymerization reaction is contained. The reaction can be carried out without removal. Here, the polymerization inhibitor is added to prevent gelation due to polymerization of the introduced double bond. The type is not particularly limited, and specific examples thereof include hydroquinone, methylhydroquinone, hydroquinone monomethyl ether, dibutylhydroxytoluene and the like. The catalyst is also not particularly limited, but specifically, tertiary amines such as triethylamine, quaternary ammonium salts such as triethylbenzylammonium chloride, phosphorus compounds such as triphenylphosphine, and organic metals such as chromium and tin. A compound etc. are mentioned.

[Third embodiment]
The third embodiment of the copolymer (A) of the present invention has a hydroxy group formed by ring-opening addition of the unsaturated carboxylic acid (b-1) to the epoxy group of the epoxy group-containing copolymer (P). An unsaturated group-containing copolymer (A1) and an ethylenically unsaturated group-containing reactive monomer (b-2) having a hydroxyl group-reactive functional group in the hydroxyl group of the unsaturated group-containing copolymer (A1). And an unsaturated group-containing copolymer (A2). The third embodiment of the copolymer (A) of the present invention is preferably a mixture of the unsaturated group-containing copolymer (A1) and the unsaturated group-containing copolymer (A2). The unsaturated group equivalent of the copolymer (A) of this embodiment is 2500 g / mol or less. The unsaturated group-containing copolymer (A1) and the unsaturated group-containing copolymer (A2) according to the third embodiment are respectively the unsaturated group-containing copolymer (A1) and the second group according to the first embodiment. Since it is the same as the unsaturated group-containing copolymer (A2) according to the embodiment, its explanation is omitted.

[Method for producing mixture of unsaturated group-containing copolymer (A1) and unsaturated group-containing copolymer (A2)]
The unsaturated group-containing copolymer (A1) and the unsaturated group-containing copolymer (A2) are mixed, for example, in a mass ratio (A1 / A2) of 5/95 to 95/5 to form an unsaturated group. A copolymer (A) having an equivalent weight of 2500 g / mol or less is prepared.

[Characteristics of Copolymer (A)]
The molecular weight (polystyrene-equivalent weight average molecular weight) of the copolymer (A) of the present invention obtained in the above-mentioned first embodiment to third embodiment is preferably 1,000 to 50,000, more preferably 3,000 to 40,000. .. When this molecular weight is 1,000 or more, the solvent resistance and thermal decomposition resistance of the cured film can be sufficiently secured. On the other hand, when the molecular weight is 50,000 or less, the molecular weight and the viscosity can be controlled in an appropriate range, which is practical.

  The unsaturated group equivalent of the copolymer (A) is 2500 g / mol or less, preferably 100 to 2500 g / mol, more preferably 200 to 2000 g / mol. When the unsaturated group equivalent is 100 g / mol or more, it is more effective to further enhance the thermal decomposition resistance and the thermal yellowing resistance. An unsaturated group equivalent of 2500 g / mol or less, more preferably 2000 g / mol or less, is required to provide high sensitivity and desired photocurability.

  The refractive index of the copolymer (A) is preferably less than 1.50 under the conditions of 589 nm and 20 ° C. When it is less than 1.50, the refractive index is sufficiently lower than the refractive index of the fluorine-free photocurable acrylic resin, and good low reflectance of the cured film can be obtained.

[Photosensitive resin composition]
Photosensitive resin composition of the present invention The present invention contains a copolymer (A), a solvent (B) and optionally a reactive diluent (C). The photosensitive resin composition of the present invention preferably contains the copolymer (A), the solvent (B), the reactive diluent (C), and the photopolymerization initiator (D).

[Solvent (B)]
The solvent (B) is not particularly limited as long as it is a solvent that does not react with the copolymer (A). As the solvent (B), the same solvent as used in the production of the copolymer (A) can be used, and the solvent contained after the reaction can be used as it is or further added. In addition, when other components are added, they may coexist there. Specific examples of the solvent (B) include propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether acetate, ethyl acetate, butyl acetate, isopropyl acetate, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, tripropylene glycol. Examples thereof include monomethyl ether, ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, ethylene glycol monoethyl ether acetate and diethylene glycol ethyl ether acetate. These may be used alone or in combination of two or more. Among these, glycol ether solvents such as propylene glycol monomethyl ether and propylene glycol monomethyl ether acetate used in the production of the copolymer (A) are preferable.

  The blending amount of the solvent (B) in the resin composition or the photosensitive resin composition of the present embodiment is generally 30 to 1000 parts by mass when the sum of the components excluding the solvent (B) in the composition is 100 parts by mass. Parts, preferably 50 to 800 parts by mass, more preferably 100 to 700 parts by mass. If it is the compounding quantity of this range, it will become a resin composition or a photosensitive resin composition which has suitable viscosity.

[Reactive diluent (C)]
The reactive diluent (C) is not particularly limited, but those containing an ethylenically unsaturated double bond, a vinyl group and a (meth) acryloyloxy group are preferable. Specific examples thereof include aromatic vinyl monomers such as styrene, α-methylstyrene, α-chloromethylstyrene, vinyltoluene, divinylbenzene, diallylphthalate and diallylbenzenephosphonate; polycarboxylic acids such as vinyl acetate and vinyl adipate. Monomers: methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, β-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, ethylene glycol di (meth) acrylate , Diethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, ethylene glycol di (meth) acrylate, trimethylolpropane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, Examples include (meth) acrylic monomers such as dipentaerythritol hexa (meth) acrylate and tri (meth) acrylate of tris (hydroxyethyl) isocyanurate; triallyl cyanurate and the like. These may be used alone or in combination of two or more.

  The compounding amount of the reactive diluent (C) in the resin composition or photosensitive resin composition of the present embodiment is generally 10 when the total amount of the components excluding the solvent (B) in the composition is 100% by mass. -90 mass%, preferably 20-80 mass%, more preferably 25-70 mass%. If it is the compounding quantity of this range, it will become a resin composition or photosensitive resin composition which has suitable viscosity, and a photosensitive resin composition has suitable photocurability.

[Photopolymerization initiator (D)]
The photopolymerization initiator (D) is not particularly limited, but specific examples thereof include benzoin, benzoin methyl ether, benzoin ethyl ether, and other benzoins and alkyl ethers thereof; acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1 , 1-dichloroacetophenone, 4- (1-t-butyldioxy-1-methylethyl) acetophenone and other acetophenones; 2-methylanthraquinone, 2-amylanthraquinone, 2-t-butylanthraquinone, 1-chloroanthraquinone and other anthraquinones Thioxanthones such as 2,4-dimethylthioxanthone, 2,4-diisopropylthioxanthone and 2-chlorothioxanthone; ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal; benzophenone and 4- (1-t-butyldioxy-1- Benzophenones such as methylethyl) benzophenone and 3,3 ′, 4,4′-tetrakis (t-butyldioxycarbonyl) benzophenone; 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propane -1-one; 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone-1; acylphosphine oxides; and xanthones. These may be used alone or in combination of two or more.

  The blending amount of the photopolymerization initiator (D) in the photosensitive resin composition of the present embodiment is generally 0.1 when the total amount of the components excluding the solvent (B) in the photosensitive resin composition is 100 parts by mass. To 30 parts by mass, preferably 0.5 to 20 parts by mass, more preferably 1 to 15 parts by mass. A blending amount within this range results in a photosensitive resin composition having appropriate photocurability.

[Composition of photosensitive resin composition]
The blending amounts of the copolymer (A), the solvent (B), the reactive diluent (C), and the photopolymerization initiator (D) of the photosensitive resin composition of the present embodiment are the same as those in the photosensitive resin composition. When the total amount of components excluding the solvent (B) is 100 parts by mass, preferably the copolymer (A) is 5 to 80 parts by mass, the solvent (B) is 30 to 1000 parts by mass, and the reactive diluent (C). Is 10 to 90 parts by mass, the photopolymerization initiator (D) is 0.1 to 30 parts by mass, and more preferably 8 to 70 parts by mass of the copolymer (A) and 50 to 800 of the solvent (B). 20 parts by mass of the reactive diluent (C), 0.5 to 20 parts by mass of the photopolymerization initiator (D), and more preferably 10 to 60 parts by mass of the copolymer (A). Parts, the solvent (B) is 100 to 700 parts by mass, the reactive diluent (C) is 25 to 70 parts by mass, and the photopolymerization initiator (D) is 1 to 15 parts by mass.

  The photosensitive resin composition of the present embodiment, in addition to the above components, in order to impart predetermined characteristics, known additives such as known coupling agents, leveling agents, thermal polymerization inhibitors, and known You may mix | blend the colorant of this, a filler, a dispersing agent, etc. The blending amount of these additives is not particularly limited as long as the effects of the present invention are not impaired.

[Method for producing photosensitive resin composition]
The photosensitive resin composition of the present embodiment can be produced by mixing the above components using a known mixing device. The photosensitive resin composition of the present embodiment is prepared by first preparing a resin composition containing a copolymer (A) and a solvent (B), and then preparing a reactive diluent (C), a photopolymerization initiator ( It is also possible to mix and produce D). The resin composition can be used for preparing the photosensitive resin composition of the present embodiment, and can also be used for other purposes.

  The photosensitive resin composition of the present embodiment obtained as described above can provide a cured film having excellent photosensitivity, thermal decomposition resistance, thermal yellowing resistance, and low reflectance. Therefore, the photosensitive resin composition of the present embodiment, various resists, in particular, a microlens surface capable of suppressing reflected light, a substrate incorporated in an image display device capable of suppressing reflection of external light, a color filter, a black matrix. It is suitable for use as a resist used for manufacturing a column spacer, a protective film, and the like. In addition, the photosensitive resin composition of the present embodiment gives a cured film excellent in various properties such as heat decomposition resistance, heat yellowing, high transparency, and low reflectivity, and therefore various coatings, adhesives, printing It is also suitable for use as a binder for inks and the like.

[Registration]
Next, the resist prepared using the photosensitive resin composition of the present invention will be described. The resist of the present invention refers to a cured film obtained from the above photosensitive resin composition. The resist of one embodiment of the present invention includes a glass substrate, a silicon substrate, a polycarbonate substrate, a polyester substrate, a polyamide substrate, a polyamideimide substrate, a polyimide substrate, an aluminum substrate, a printed wiring board, an array substrate, and other substrates on which the present invention is applied. The photosensitive resin composition is applied and the coating film is exposed to light to cure the exposed portion. Then, by baking, a predetermined cured film can be formed on the substrate. The method for applying the photosensitive resin composition is not particularly limited, but a screen printing method, a roll coating method, a curtain coating method, a spray coating method, a spin coating method, a slit coating method or the like can be used. In addition, after applying the photosensitive resin composition, the solvent (B) may be volatilized by heating using a heating means such as a circulation oven, an infrared heater, or a hot plate, if necessary. The heating conditions are not particularly limited and may be appropriately set depending on the type of photosensitive resin composition used. Generally, heating may be performed at a temperature of 50 ° C. to 120 ° C. for 30 seconds to 30 minutes.

  The light source used for the exposure is not particularly limited, but a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, a xenon lamp, a metal halide lamp and the like can be used. The amount of exposure is also not particularly limited, and may be appropriately adjusted according to the type of photosensitive resin composition used. The baking conditions are not particularly limited, and heat treatment may be performed depending on the type of photosensitive resin composition used. Generally, heating may be performed at 130 to 250 ° C. for 10 to 60 minutes.

  Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples. In this example, all parts and percentages are based on mass unless otherwise specified.

<Measurement method of molecular weight>
The molecular weight (Mw) means a standard polystyrene-equivalent weight average molecular weight measured by gel permeation chromatography (GPC) under the following conditions.
Column: Showdex (registered trademark) LF-804 + LF-804 (Showa Denko KK)
Column temperature: 40 ° C
Sample: 0.2% tetrahydrofuran solution of copolymer (A) Developing solvent: Tetrahydrofuran Detector: Differential refractometer (Showdex RI-71S) (manufactured by Showa Denko KK)
Flow rate: 1 mL / min

<Measuring method of unsaturated group equivalent>
It is the mass of the polymer per the number of moles of the ethylenically unsaturated group, and is a calculated value calculated based on the amount of the monomer used.

<Method of measuring refractive index>
The refractive index means the refractive index of the copolymer (A) measured using a refractometer. The refractive index of the resin composition (sample) containing the copolymer (A) and the solvent (B) of the present invention is measured under the following conditions, and then the refractive index of the solvent (B) is measured under the following conditions. Next, the content (solid content) of the copolymer (A) contained in the sample was measured according to JIS K6901 5.11, and the refractive index of the copolymer (A) alone contained in the sample was calculated using the following formula. calculate.
Measuring instrument: J-357 Automatic Refractometer (Rudolf Research Analytical)
Measurement wavelength: 589 nm
Measurement temperature: 20 ℃

  Refractive index of copolymer (A) alone = (refractive index of sample−refractive index of solvent (B)) ÷ solid content × 100 + refractive index of solvent (B)

<Method of measuring solid content>
The heating residue when the sample obtained in the following synthesis example was heated at 130 ° C. for 2 hours was measured.

<Method of measuring fluorine equivalent>
It is the mass of the polymer per the number of moles of the fluorine atom, and is a calculated value calculated based on the amount of the monomer used.

A production example of a resin composition (sample) containing the copolymer (A) and the solvent (B) of the present invention is shown below.
<Synthesis example 1>
161.3 g of propylene glycol monomethyl ether acetate was placed in a flask equipped with a stirrer, a dropping funnel, a condenser, a thermometer, and a gas introduction tube, and the mixture was stirred while being replaced with nitrogen gas, and heated to 80 ° C. Next, 9.9 g of dicyclopentanyl methacrylate (a-1A), 257.7 g of 2,2,2-trifluoroethyl methacrylate (a-2), and 96.1 g of glycidyl methacrylate (a-3). 21.8 g of 2,2′-azobis (2,4-dimethylvaleronitrile) (polymerization initiator, 6 parts by mass relative to 100 parts by mass of the monomer mixture) was added to the monomer mixture consisting of It dripped into the said flask over 1 hour. After completion of the dropping, the mixture was stirred at 80 ° C. for 2 hours to carry out a copolymerization reaction to obtain an epoxy group-containing copolymer (P). Next, after the air in the flask was replaced with air, 47.3 g of acrylic acid (b-1) and 1.2 g of triphenylphosphine (catalyst, monomer (a-1A), (a-2), (a -3), 0.3 parts by mass relative to 100 parts by mass of (b-1) in total, and 1.2 g of hydroquinone monomethyl ether (polymerization inhibitor, monomer (a-1A), (a-2), (A-3) and (b-1) (0.3 parts by mass relative to 100 parts by mass in total) are added, and the mixture is reacted at 120 ° C. for 10 hours to prepare a copolymer composed of the unsaturated group-containing copolymer (A1). A solution containing the polymer (A) was obtained. Next, to the solution containing this copolymer (A), 296.4 g of propylene glycol monomethyl ether acetate was added as a solvent (B), and sample No. Got 1. The blending ratio of each monomer when the total amount of the monomers (a-1A), (a-2), and (a-3) is converted to 100 mol%, the fluorine equivalent of the epoxy group-containing copolymer (P), and the The molecular weight, unsaturated group equivalent weight, and refractive index of the polymer (A) are shown in Table 1.

<Synthesis examples 2 to 4, 7 to 9, comparative synthesis examples 1 to 4>
A solution containing the copolymer (A) was produced and propylene glycol monomethyl ether acetate was added as the solvent (B) in the same manner as in Synthesis Example 1 except that the mixing ratios of the monomers shown in Table 1 were used. ． 2-4 and 7-13 were obtained. Table 1 shows the fluorine equivalent of the epoxy group-containing copolymer (P) contained in each sample, the molecular weight of the copolymer (A), the unsaturated group equivalent, and the refractive index.

<Synthesis example 5>
Copolymer (A) in the same manner as in Synthesis Example 1 except that norbornene (a-1B) was used instead of dicyclopentanyl methacrylate (a-1A), and the mixing ratio of the monomers shown in Table 1 was used. Was prepared, and propylene glycol monomethyl ether acetate was added as the solvent (B) to prepare a sample No. Got 5. Table 1 shows the fluorine equivalent of the epoxy group-containing copolymer (P) contained in each sample, the molecular weight of the copolymer (A), the unsaturated group equivalent, and the refractive index.

<Synthesis example 6>
In the same manner as in Synthesis Example 1, after adding 156.1 g of propylene glycol monomethyl ether acetate to the flask, the flask was stirred while being replaced with nitrogen gas, and the temperature was raised to 80 ° C. Next, from 6.2 g of dicyclopentanyl methacrylate (a-1A), 285.9 g of 1H, 1H, 5H-octafluoropentyl methacrylate (a-2) and 59.7 g of glycidyl methacrylate (a-3). 21.1 g of 2,2′-azobis (2,4-dimethylvaleronitrile) (polymerization initiator, 6 parts by mass relative to 100 parts by mass of the monomer mixture) was added to the monomer mixture consisting of It dripped in the flask over 1 hour. After completion of the dropping, the mixture was stirred at 80 ° C. for 2 hours to carry out a copolymerization reaction to obtain an epoxy group-containing copolymer (P). Next, after the air in the flask was replaced with air, 29.4 g of acrylic acid (b-1), 1.2 g of triphenylphosphine (catalyst, monomer (a-1A), (a-2), (a -3), 0.3 parts by mass relative to 100 parts by mass of (b-1) in total, and 1.2 g of hydroquinone monomethyl ether (polymerization inhibitor, monomer (a-1A), (a-2), (A-3) and (b-1) (0.3 parts by mass relative to 100 parts by mass in total) are added, and the mixture is reacted at 120 ° C. for 10 hours to give a hydroxy group-containing unsaturated group-containing copolymer (A1). ) Was obtained. Next, 30.7 g of 2-isocyanatoethyl methacrylate (b-2) was added, and the mixture was reacted at 110 ° C. for 1 hour to contain the copolymer (A) composed of the unsaturated group-containing copolymer (A2). A solution was obtained. Next, to the solution of this copolymer (A), 308.2 g of propylene glycol monomethyl ether acetate was added as a solvent (B), and sample No. Got 6. The blending ratio of each monomer when the total amount of the monomers (a-1B), (a-2), and (a-3) is converted to 100 mol%, the fluorine equivalent of the epoxy group-containing copolymer (P), and the The molecular weight, unsaturated group equivalent weight, and refractive index of the polymer (A) are shown in Table 1.

Next, sample No. A photosensitive resin composition was prepared using 1 to 13.
<Preparation of photosensitive resin composition>
Sample No. 100 parts by mass of pentaerythritol tetraacrylate (reactive diluent (C)) and 2,2-dimethoxy-2-phenylacetophenone (photopolymerization initiator (D)) 10 with respect to 100 parts by mass of the solid content of 1 to 13. A transparent resist was prepared by adding parts by mass (Examples 1 to 9 and Comparative Examples 1 to 4).
The residue of the sample excluding the solvent (propylene glycol monomethyl ether acetate) is defined as "solid content".

<Pattern formation by photosensitive resin composition>
The prepared photosensitive resin composition was spin-coated on a 5 cm square glass substrate (non-alkali glass substrate) so that the final cured coating film had an average thickness of 2.5 μm, and then at 100 ° C. for 3 minutes. The solvent was volatilized by heating. Next, the entire surface of the coating film was exposed with an apparatus (exposure amount 80 mJ / cm ² ), photocured, and then baked at 230 ° C. for 30 minutes to obtain a resist which was a cured coating film.

<Evaluation of resist>
The resist was evaluated for transparency, smoothness, thermal decomposition resistance, thermal yellowing, hardness, and reflectance.

(1) Evaluation of transparency The transparency was visually confirmed.

(2) Evaluation of smoothness The thickness of the four corners and the center of the glass substrate was measured by a stylus type step gauge ET4000M manufactured by Kosaka Laboratory Ltd., and the smoothness of the resist was determined from the difference between the maximum and minimum measured values. Was evaluated.

(3) Evaluation of thermal decomposition resistance Evaluation was carried out by thermogravimetric analysis (TGA) using a sample obtained by cutting out a coating film formed on a glass substrate. In this analysis, the weight change rate between this sample and the sample which was heated to 220 ° C. at a temperature rising rate of 10 ° C./min in a nitrogen gas atmosphere and held for 2 hours was obtained.

(4) Evaluation of heat-resistant yellowing The coating film formed on a glass substrate was allowed to stand in a dryer at 230 ° C for 1 hour in a nitrogen gas atmosphere, and the change in color (ΔE ^* ab) of the coating film before and after heat treatment was observed ^. Comparison was performed using a color difference meter SE2000 manufactured by Nippon Denshoku Industries Co., Ltd.

(5) Evaluation of hardness The hardness of the coating film formed on the glass substrate was measured with a pencil hardness tester No. No. manufactured by Yasuda Seiki Co., Ltd. The comparison was performed using a 553-M Scratch Hardness Tester (scratch load: 750 g, scratch rate: 80 mm / min).

(6) Evaluation of reflectance The reflectance of the coating film formed on the glass substrate was measured using a color difference meter SE2000 manufactured by Nippon Denshoku Industries Co., Ltd. The reflectance here means the light reflectance of the coating film formed on the glass substrate when the light reflectance of the ceramic standard plate is 100%, as the relative reflectance. The diameter for measuring the light reflectance was 30 mmφ and the light wavelength was 550 nm.

  Table 2 shows the evaluation results of the transparency, smoothness, thermal decomposition resistance, thermal yellowing resistance, hardness, and reflectance of the cured coating film.

  As can be seen from the results in Table 2, in Examples 1 to 9, by using the copolymer (A) of the present invention, excellent hardness, smoothness, thermal decomposition resistance, thermal yellowing, and low reflectance were obtained. A transparent resist that develops was obtained. On the other hand, in Comparative Examples 1 to 4, since the copolymer (A) of the present invention was not used, any one of hardness, smoothness, thermal decomposition resistance, thermal yellowing resistance, and low reflectance was insufficient. A resist was obtained. In particular, in Comparative Examples 2 and 4, the fluorine-containing copolymer was poorly compatible with other photosensitive resin compositions, and the resist was insufficient in all properties.

  From the above, by using an acrylic resin having an excellent low refractive index while having photosensitivity that exhibits photocurability, it is possible to reduce the reflection of all electronic material members such as microlenses and image display devices. It is possible to provide a resist that contributes to the above, and a photosensitive resin composition suitable for the resist.

Claims (8)

The unsaturated group-containing copolymer (A1) having a hydroxy group formed by ring-opening addition of the unsaturated carboxylic acid (b-1) to the epoxy group of the epoxy group-containing copolymer (P), and the hydroxy group An unsaturated group-containing copolymer obtained by adding an ethylenically unsaturated group-containing reactive monomer (b-2) having a functional group that reacts with a hydroxy group to the hydroxy group of the unsaturated group-containing copolymer (A1) Coalescence (A2)
A copolymer (A) containing at least one selected from the group consisting of:
The epoxy group-containing copolymer (P) is
It is composed of a structural unit derived from a polymerizable monomer (a-1A) having a bridged cyclic hydrocarbon group having 10 to 20 carbon atoms and a structural unit derived from a polymerizable monomer (a-1B) represented by the following chemical formula (1). At least one selected from the group;
A structural unit derived from a fluorine-containing (meth) acrylate (a-2) represented by the following chemical formula (2),
A copolymer containing a structural unit derived from an epoxy group-containing (meth) acrylate (a-3),
The copolymer (A), which has an unsaturated group equivalent of 2500 g / mol or less.

(X and Y in the formula (1) each independently represent a hydrogen atom, a linear or branched hydrocarbon group having 1 to 4 carbon atoms, and R 1 and R 2 each independently represent hydrogen. (A hydrocarbon group having 1 to 20 carbon atoms, which may have an atom, a carboxy group or a substituent, and may have a cyclic structure connecting R1 and R2.)

(In the formula (2), R3 represents a hydrogen atom or a methyl group, L is _{-O -, - O-CH 2} -CH (OH) -CH 2 -, - O-NH-C (= O) -CH Z is any chain of _2- CH ₂ — Z is independently a hydrogen atom, a fluorine atom, a CF ₃ group, a C ₂ F ₅ group, a C ₃ F ₇ group or a hydroxy group, and n is 0 to 0. It is an integer of 12, provided that at least three fluorine atoms are included in the formula (2).   The copolymer (A) according to claim 1, which has a refractive index of less than 1.50.   The copolymer (A) according to claim 1 or 2, wherein the epoxy group-containing copolymer (P) has a fluorine equivalent of 100 g / mol or less.   The polymerizable monomer (a-1A) having a bridged cyclic hydrocarbon group having 10 to 20 carbon atoms is dicyclopentenyl (meth) acrylate, dicyclopentanyl (meth) acrylate, isobornyl (meth) acrylate, and adamantyl. The copolymer (A) according to any one of claims 1 to 3, which contains at least one selected from the group consisting of (meth) acrylates.   A resin composition containing the copolymer (A) according to any one of claims 1 to 4 and a solvent (B).   The resin composition according to claim 5, further comprising a reactive diluent (C).   The photosensitive resin composition according to claim 6, further comprising a photopolymerization initiator (D).   A resist using the photosensitive resin composition according to claim 7.