JP7630249B2 - Photosensitive composition - Google Patents

Description

The present invention relates to a photosensitive composition. More specifically, the present invention relates to a photosensitive composition that can give a cured product having excellent elastic recovery, adhesion, hardness and durability.

Background Art Photosensitive compositions that can react and harden when irradiated with light are being considered for use in a variety of applications, such as color filters, photoresists, inks, hard coats, optical films, and other optical components used in liquid crystal display devices and the like, as well as in electric and electronic devices, and resin compositions are being developed according to the performance required for each application.
In recent years, optical members and electric/electronic devices have become smaller, thinner, and more energy-efficient, and this has led to demands for higher performance in the various members used in these devices. In order to meet such demands, research has been conducted on photosensitive compositions that can be used as materials for the various members.
Various photosensitive compositions have been proposed so far.
For example, Patent Document 1 discloses an active energy ray-curable coating composition that contains 10 to 80 mass % of a specific mono- or polypentaerythritol poly(meth)acrylate compound modified with caprolactone and 20 to 40 mass % of an isocyanurate skeleton-containing urethane (meth)acrylate compound, based on 100 mass % of a radical polymerizable compound, as a composition that is excellent in reactivity to active energy rays and capable of forming a cured coating film having excellent weather resistance and abrasion resistance. Patent Document 2 discloses an active energy ray-curable coating resin composition that contains a (meth)acrylate compound having a structure in which ε-caprolactone is ring-opened, and a phosphoric acid ester compound having a hydrocarbon group having 8 or more carbon atoms and an ethylene oxide group. In addition, Patent Document 3 describes an active energy ray-curable composition that has excellent releasability from a mold after curing and excellent water resistance, the active energy ray-curable composition containing a specific tetra- to hexafunctional (meth)acrylate, a bifunctional (meth)acrylate having an alicyclic skeleton, a tri- to hexafunctional (meth)acrylate having a specific divalent organic group in the molecule, and a specific photopolymerization initiator. In addition, Patent Document 4 describes a photocurable composition that contains a specific cyclopolymerizable monomer, a polyfunctional radically polymerizable compound, and a photoradical polymerization initiator.

The above-mentioned prior art documents demonstrate the performance required for various applications, but each performance is not sufficient, and there is room for improvement, particularly in the durability of the cured product.

Patent No. 5283485 Patent No. 6370748 JP 2019-94484 A Patent No. 5475173

Incidentally, when such a photosensitive resin composition is used to form a hard coat, an overcoat, an optical film, etc., it is desirable that the surface hardness of the cured film is high in order to prevent the surface from being scratched. It is also desirable that the cured film has excellent elastic recovery. Furthermore, it is desirable that the cured film has excellent adhesion to the substrate. And it is desirable that these properties are maintained even under severe environments and that the cured film has excellent durability.
However, with conventional photosensitive compositions, it has not been easy to obtain a cured product that is excellent in all of surface hardness, elastic recovery, adhesion to substrates, and durability.
The present invention has been made in consideration of the above-mentioned current situation, and has an object to provide a photosensitive composition that can give a cured product having excellent elastic recovery, hardness, adhesion and durability.

As a result of intensive research, the present inventors have found that a specific photosensitive composition can give a cured product having excellent elastic recovery, hardness, adhesion, and durability, and have completed the present invention. That is, the object of the present invention is achieved by the following <1> to <9>.
<1> A photosensitive composition comprising (A) a polyfunctional (meth)acrylate of a lactone-modified polyhydric aliphatic alcohol, (B) a cyclopolymerizable monomer, and (C) an acylphosphine oxide-based photopolymerization initiator.
<2> The photosensitive composition according to <1>, wherein the polyfunctional (meth)acrylate (A) of a lactone-modified polyhydric aliphatic alcohol is a compound represented by the following general formula (1):

（式（１）中、Ｒ^１、Ｒ^２及びＲ^３は、同一又は異なって、有機基を表す。Ｘは、一般式（２）で表される構造を表す。ａ及びｃは、同一又は異なって、０～３の整数であり、ｂは、０～２の整数であり、ａ＋ｂｌ＋ｃ≧６を満たす。ｌは、０～６の整数である。
式（２）中、Ｒ^４は水素原子又はメチル基を表す。Ｒ^５は、炭素数１～８の炭化水素基を表す。ｍは、１～３の整数を表す。）
＜３＞前記環化重合性モノマー（Ｂ）は、下記一般式（３）で表される化合物であることを特徴とする＜１＞又は＜２＞に記載の感光性組成物。

In formula (1), R ¹ , R ² and R ³ are the same or different and represent an organic group. X represents a structure represented by general formula (2). a and c are the same or different and represent an integer of 0 to 3, b is an integer of 0 to 2 and satisfies a+b1+c≧6. 1 is an integer of 0 to 6.
In formula (2), R ⁴ represents a hydrogen atom or a methyl group. R ⁵ represents a hydrocarbon group having 1 to 8 carbon atoms. m represents an integer of 1 to 3.
<3> The photosensitive composition according to <1> or <2>, wherein the cyclopolymerizable monomer (B) is a compound represented by the following general formula (3):

（式中、Ｒ^６は、水素原子又はメチル基、Ｒ^７は、水素原子又は１価の有機基を表す。）
＜４＞
前記ラクトン変性多価脂肪族アルコールの多官能（メタ）アクリレート（Ａ）と、環化重合性モノマー（Ｂ）との質量比（Ａ／Ｂ）は、１／１～１０／１であることを特徴とする＜１＞～＜３＞のいずれかに記載の感光性組成物。
＜５＞
前記環化重合性モノマー（Ｂ）の含有量は、感光性組成物１００質量％中６０質量％以下であることを特徴とする＜１＞～＜４＞のいずれかに記載の感光性組成物。
＜６＞
前記アシルフォスフィンオキサイド系光重合開始剤（Ｃ）の含有量は、感光性組成物１００質量％中０．１～２質量％であることを特徴とする＜１＞～＜５＞のいずれかに記載の感光性組成物。
＜７＞
前記感光性組成物は、更に、重合禁止剤（Ｄ）を含むことを特徴とする＜１＞～＜６＞のいずれかに記載の感光性組成物。
＜８＞
前記感光性組成物は、溶剤の含有量が、感光性組成物１００質量％中３質量％以下であることを特徴とする＜１＞～＜７＞のいずれかに記載の感光性組成物。
＜９＞
前記感光性組成物は、着色剤の含有量が、感光性組成物１００質量％中３質量％以下であることを特徴とする＜１＞～＜８＞のいずれかに記載の感光性組成物。

(In the formula, ^R6 represents a hydrogen atom or a methyl group, and ^R7 represents a hydrogen atom or a monovalent organic group.)
＜4＞
The photosensitive composition according to any one of <1> to <3>, wherein a mass ratio (A/B) of the polyfunctional (meth)acrylate of the lactone-modified polyhydric aliphatic alcohol (A) to the cyclopolymerizable monomer (B) is 1/1 to 10/1.
＜5＞
The photosensitive composition according to any one of <1> to <4>, wherein the content of the cyclopolymerizable monomer (B) is 60% by mass or less based on 100% by mass of the photosensitive composition.
＜6＞
The photosensitive composition according to any one of <1> to <5>, wherein the content of the acylphosphine oxide-based photopolymerization initiator (C) is 0.1 to 2 mass% in 100 mass% of the photosensitive composition.
＜７＞
The photosensitive composition according to any one of <1> to <6>, further comprising a polymerization inhibitor (D).
＜8＞
The photosensitive composition according to any one of <1> to <7>, wherein the photosensitive composition has a solvent content of 3% by mass or less based on 100% by mass of the photosensitive composition.
＜9＞
The photosensitive composition according to any one of <1> to <8>, wherein the content of the colorant in the photosensitive composition is 3% by mass or less based on 100% by mass of the photosensitive composition.

The photosensitive composition of the present invention can provide a cured product having excellent elastic recovery, hardness, adhesion, and durability. The photosensitive composition of the present invention can be used in a variety of applications, such as hard coats, overcoats, optical films, adhesives, sealants, insulating films, and optical filters used as near-infrared or infrared cut filters.

The present invention will be described in detail below.
In addition, a combination of two or more of the individual preferred embodiments of the present invention described below is also a preferred embodiment of the present invention.
In this specification, "(meth)acrylic acid" means "acrylic acid and/or methacrylic acid", and "(meth)acrylate" means "acrylate and/or methacrylate".
In the present application, a numerical range "Min to Max" means a range from the minimum value Min to the maximum value Max. Furthermore, when the upper and lower limit values are described in stages, a suitable numerical range can be set by appropriately combining the upper and lower limit values described separately.

<Photosensitive Composition>
The present invention relates to a photosensitive composition comprising (A) a polyfunctional (meth)acrylate of a lactone-modified polyhydric aliphatic alcohol, (B) a cyclopolymerizable monomer, and (C) an acylphosphine oxide-based photopolymerization initiator.
Since the photosensitive composition of the present invention has the above-mentioned constitution, it can provide a cured product having excellent elastic recovery, hardness, adhesion, and durability. The reason why the photosensitive composition of the present invention can provide a cured product having excellent elastic recovery, hardness, adhesion, and durability is not clear, but it is considered to be due to the following reasons. That is, by including a polyfunctional (meth)acrylate having a structure of a lactone-modified polyhydric aliphatic alcohol, it is possible to form a dense crosslinked structure during curing due to its multifunctionality, and as a result, it is possible to increase the hardness and elastic recovery rate of the cured product. In addition, since it is bulky, it is possible to prevent curing shrinkage and improve adhesion. By including a cyclopolymerizable monomer, it is possible to prevent curing shrinkage and improve adhesion and durability. Furthermore, by including an acylphosphine oxide-based photopolymerization initiator, curing can be performed sufficiently.
The photosensitive composition of the present invention contains a polyfunctional (meth)acrylate of a lactone-modified polyhydric aliphatic alcohol (A), a cyclopolymerizable monomer (B), and an acylphosphine oxide-based photopolymerization initiator (C). Each component will be described below.
(A) Polyfunctional (meth)acrylate of lactone-modified polyhydric aliphatic alcohol The polyfunctional (meth)acrylate of lactone-modified polyhydric aliphatic alcohol in the present invention is a polyfunctional (meth)acrylate having a structure in which a polyhydric aliphatic alcohol is modified with lactone and having two or more (meth)acryloyl groups in the molecule.
The lactone modification means that the lactone compound has a ring-opening addition structure.
The lactone modification may be a structure in which one molecule of a lactone compound is added through ring-opening, or a structure in which two or more molecules of a lactone compound are added through ring-opening.
The structure in which the polyhydric aliphatic alcohol is modified with lactone is preferably, for example, a structure in which a lactone compound is added to the hydroxyl group of the polyhydric aliphatic alcohol by ring-opening addition.
Examples of the polyfunctional (meth)acrylate of the lactone-modified polyhydric aliphatic alcohol include compounds obtained by reacting a polyhydric aliphatic alcohol, a lactone compound, and raw material components containing (meth)acrylic acid.
The polyhydric aliphatic alcohol is not particularly limited, but examples thereof include trimethylolethane, ditrimethylolethane, trimethylolpropane, ditrimethylolpropane, pentaerythritol, dipentaerythritol, tripentaerythritol, and glycerin.
The lactone compound is not particularly limited, but examples thereof include β-propiolactone, γ-butyrolactone, γ-valerolactone, δ-valerolactone, ε-caprolactone, enantholactone, caprylolactone, dodecanolactone, and lactones substituted with one or more alkyl groups such as methyl groups.
The polyfunctional (meth)acrylate of the lactone-modified polyhydric aliphatic alcohol is not particularly limited as long as it is a di- or higher functional (meth)acrylate, but is preferably a hexa- or higher functional (meth)acrylate in that it can suppress tack (adhesiveness) of the cured product and further improve adhesion.
As the polyfunctional (meth)acrylate of the lactone-modified polyhydric aliphatic alcohol, a compound represented by the following general formula (1) is preferably used.

（式（１）中、Ｒ^１、Ｒ^２及びＲ^３は、同一又は異なって、有機基を表す。Ｘは、一般式（２）で表される構造を表す。ａ及びｃは、同一又は異なって、０～３の整数であり、ｂは、０～２の整数であり、ａ+ｂｌ+ｃ≧６を満たす。ｌは、０～６の整数である。
式（２）中、Ｒ^４は水素原子又はメチル基を表す。Ｒ^５は、炭素数１～８の炭化水素基を表す。ｍは、１～３の整数を表す。）
上記一般式（１）において、Ｒ^１、Ｒ^２及びＲ^３は、同一又は異なって、有機基を表す。
上記有機基としては、鎖状若しくは環状の飽和又は不飽和の炭化水素基、及び、上記炭化水素基と共に－Ｏ－、－Ｓ－、－ＳＯ－、－ＳＯ_２－等の結合を含む基が挙げられる。
上記炭化水素基の炭素数は、１～２０であることが好ましく、２～１５であることがより好ましく、３～１０であることが更に好ましい。
上記炭化水素基は、一価であってもよいし、二価以上であってもよい。
上記鎖状の飽和炭化水素基としては、直鎖状又は分岐状の飽和脂肪族炭化水素基が挙げられる。一価の飽和脂肪族炭化水素基の具体例としては、例えばメチル基、エチル基、ｎ－プロピル基、イソプロピル基、ｎ－ブチル基、イソブチル基、ｔ－ブチル基、ｔ－アミル基、オクチル基、２－エチルヘキシル基、ラウリル基、ステアリル基等のアルキル基が挙げられる。
上記鎖状の不飽和炭化水素基としては、直鎖状又は分岐状の不飽和脂肪族炭化水素基が挙げられる。一価の不飽和脂肪族炭化水素基の具体例としては、例えばビニル基、２－プロペニル基、イソプロペニル基、１－ブテニル基、２－ブテニル基、１－ペンテニル基、２－ペンテニル基、２－メチル－１－ブテニル基、１－ヘキセニル基、２－ヘキセニル基、１－ヘプテニル基等のアルケニル基が挙げられる。
上記環状の飽和炭化水素基としては、脂環式炭化水素基が挙げられる。一価の脂環式炭化水素基の具体例としては、例えばシクロプロピル基、シクロペンチル基、シクロヘキシル基、シクロオクチル基、シクロドデシル基、シクロへプチル基、シクロブテニル基、シクロペンテニル基、シクロヘキセニル基等のシクロアルキル基の単環式炭化水素基；ジシクロペンタニル基、ジシクロペンテニル基、トリシクロデカニル基、アダマンチル基、イソボルニル基等の多環式炭化水素基が挙げられる。

In formula (1), R ¹ , R ² and R ³ are the same or different and represent an organic group. X represents a structure represented by general formula (2). a and c are the same or different and represent an integer of 0 to 3, b is an integer of 0 to 2 and satisfies a+b1+c≧6. l is an integer of 0 to 6.
In formula (2), R ⁴ represents a hydrogen atom or a methyl group. R ⁵ represents a hydrocarbon group having 1 to 8 carbon atoms. m represents an integer of 1 to 3.
In the above general formula (1), R ¹ , R ² and R ³ are the same or different and each represents an organic group.
Examples of the organic group include linear or cyclic saturated or unsaturated hydrocarbon groups, and groups which contain a bond such as --O--, --S--, --SO--, or --SO ₂ -- together with the hydrocarbon group.
The hydrocarbon group preferably has 1 to 20 carbon atoms, more preferably 2 to 15 carbon atoms, and even more preferably 3 to 10 carbon atoms.
The hydrocarbon group may be monovalent or divalent or higher.
The chain-like saturated hydrocarbon group includes linear or branched saturated aliphatic hydrocarbon groups. Specific examples of the monovalent saturated aliphatic hydrocarbon group include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, t-amyl, octyl, 2-ethylhexyl, lauryl, and stearyl.
The chain unsaturated hydrocarbon group includes linear or branched unsaturated aliphatic hydrocarbon groups. Specific examples of the monovalent unsaturated aliphatic hydrocarbon group include alkenyl groups such as vinyl, 2-propenyl, isopropenyl, 1-butenyl, 2-butenyl, 1-pentenyl, 2-pentenyl, 2-methyl-1-butenyl, 1-hexenyl, 2-hexenyl, and 1-heptenyl.
The cyclic saturated hydrocarbon group may be an alicyclic hydrocarbon group.Specific examples of the monovalent alicyclic hydrocarbon group may include monocyclic hydrocarbon groups such as cycloalkyl groups, such as cyclopropyl, cyclopentyl, cyclohexyl, cyclooctyl, cyclododecyl, cycloheptyl, cyclobutenyl, cyclopentenyl, and cyclohexenyl; and polycyclic hydrocarbon groups such as dicyclopentanyl, dicyclopentenyl, tricyclodecanyl, adamantyl, and isobornyl.

The cyclic unsaturated hydrocarbon group may be an aromatic hydrocarbon group. Specific examples of the monovalent aromatic hydrocarbon group include aromatic hydrocarbon groups such as a phenyl group, a benzyl group, a naphthyl group, a tolyl group, and a biphenyl group.
Among these, as the monovalent hydrocarbon group, an alkyl group or an alicyclic hydrocarbon group is preferred because it is highly crosslinked, and an alkyl group is more preferred.
Examples of the divalent hydrocarbon group include divalent groups obtained by removing one hydrogen atom from the above-mentioned monovalent hydrocarbon groups (aliphatic hydrocarbon groups, alicyclic hydrocarbon groups, aromatic hydrocarbon groups), such as alkylene groups, cycloalkylene groups, arylene groups, etc. Among these, the divalent hydrocarbon group is preferably an alkylene group or a cycloalkylene group, and more preferably an alkylene group.
In the above-mentioned hydrocarbon group, at least one of the atoms constituting the hydrocarbon group may be substituted with an oxygen atom, a nitrogen atom, or a sulfur atom.
The hydrocarbon group may be a substituted hydrocarbon group, for example, a hydrocarbon group in which at least a portion of the hydrogen atoms constituting the hydrocarbon group is substituted with a hydroxyl group, a carboxyl group, an alkoxyl group, an alkyl group, a halogen atom, or the like.
Examples of groups containing an -O-, -S-, -SO-, -SO ₂ - or other bond together with the above-mentioned hydrocarbon group include -O-R-, -R-O-, -(R-O) _p -R- (wherein p is an integer of 1 to 10), -S-R-, -S-R-S-, -SO-R-, -R-SO-R-, -SO ₂ -R-, -R-SO ₂ -R- (wherein R represents the above-mentioned hydrocarbon group), etc. Of these, groups containing an -O- bond together with the above-mentioned hydrocarbon group are preferred.
The number of carbon atoms in the organic group is preferably 1 or more, more preferably 2 or more, and even more preferably 3 or more. The number of carbon atoms in the organic group is preferably 10 or less, more preferably 9 or less, and even more preferably 8 or less.
In [(XO) _a -R ¹ ]- in the above general formula (1), for example, when a is 0, R ¹ is a monovalent organic group, and when a is 1, 2 or 3, R ¹ is a divalent or higher organic group.
The organic group represented by ^R1 is preferably a chain-like saturated hydrocarbon group or a group which contains an -O-, -S-, -SO- or -SO ₂ - bond together with the saturated hydrocarbon group, and more preferably a chain-like saturated hydrocarbon group or a group which contains an -O- or -S- bond together with the saturated hydrocarbon group.
The number of carbon atoms in the organic group represented by ^R1 is preferably 1 to 20, more preferably 2 to 15, and even more preferably 3 to 10, in view of being highly crosslinked.
In -[R ³ -(OX) _c ] in the above general formula (1), for example, when c is 0, R ³ is a monovalent organic group, and when c is 1, 2 or 3, R ³ is a divalent or higher organic group.
The organic group represented by ^R3 is preferably a chain-like saturated hydrocarbon group or a group which contains an -O-, -S-, -SO- or -SO ₂ - bond together with the saturated hydrocarbon group, and more preferably a chain-like saturated hydrocarbon group or a group which contains an -O- or -S- bond together with the saturated hydrocarbon group.
The number of carbon atoms in the organic group represented by ^R3 is preferably 1 to 20, more preferably 2 to 15, and even more preferably 3 to 10, in view of being highly crosslinked.
In the above general formula (1), examples of ^R2 include the following structures.

（式中、Ｒ^８は、水素原子、置換基、又は置換基を有していてもよい炭化水素基を表す。）
上記Ｒ^８で表される置換基としては、例えば水酸基、カルボキシル基、アルコキシル基、アルキル基、ハロゲン原子等が挙げられる。上記Ｒ^８で表される炭化水素基としては、上述した炭化水素基が挙げられ、なかでも、脂肪族炭化水素基、脂環式炭化水素基が好ましく、飽和脂肪族炭化水素基がより好ましい。
上記一般式（１）において、ｌは、０～６の整数であることが好ましく、０～３の整数であることが好ましい。
上記一般式（１）において、ａ及びｃは、同一又は異なって、０～３の整数であり、ｂは、０～２の整数であり、ａ＋ｂｌ＋ｃ≧６を満たすことが好ましい。
ａ及びｃは、同一又は異なって、１～３の整数であることがより好ましい。ｂは、０～２の整数であることがより好ましい。
上記一般式（１）において、ａ＋ｂｌ＋ｃ＝６を満たすことがより好ましい。
上記一般式（１）において、Ｘは、上記一般式（２）で表される構造を表すことが好ましい。
上記一般式（２）において、Ｒ^４は、水素原子又はメチル基を表す。
Ｒ^５は、炭素数１～８の炭化水素基を表す。
Ｒ^５で表される炭化水素基としては、二価の炭化水素基が好ましい。上記二価の炭化水素基としては、上述した二価の炭化水素基と同様のものが挙げられ、なかでも、二価の脂肪族炭化水素基がより好ましく、二価の飽和脂肪族炭化水素基が更に好ましい。
Ｒ^５で表される炭化水素基の炭素数は、１～１０であることが好ましく、３～８であることがより好ましい。
上記ラクトン変性多価脂肪族アルコールの多官能（メタ）アクリレートとしては、より好ましくは、下記一般式（４）で表される化合物が挙げられる。

(In the formula, ^R8 represents a hydrogen atom, a substituent, or a hydrocarbon group which may have a substituent.)
Examples of the substituent represented by ^R8 include a hydroxyl group, a carboxyl group, an alkoxyl group, an alkyl group, a halogen atom, etc. Examples of the hydrocarbon group represented by ^R8 include the above-mentioned hydrocarbon groups, and among them, an aliphatic hydrocarbon group or an alicyclic hydrocarbon group is preferable, and a saturated aliphatic hydrocarbon group is more preferable.
In the above general formula (1), l is preferably an integer of 0 to 6, and more preferably an integer of 0 to 3.
In the above general formula (1), a and c are the same or different and are an integer of 0 to 3, b is an integer of 0 to 2, and it is preferable that a+b1+c≧6 is satisfied.
More preferably, a and c are the same or different and each is an integer of 1 to 3. More preferably, b is an integer of 0 to 2.
In the above general formula (1), it is more preferable that a+b1+c=6 is satisfied.
In the above general formula (1), X preferably represents a structure represented by the above general formula (2).
In the above general formula (2), ^R4 represents a hydrogen atom or a methyl group.
^R5 represents a hydrocarbon group having 1 to 8 carbon atoms.
The hydrocarbon group represented by ^R5 is preferably a divalent hydrocarbon group. Examples of the divalent hydrocarbon group include the same divalent hydrocarbon groups as those described above, and among them, a divalent aliphatic hydrocarbon group is more preferable, and a divalent saturated aliphatic hydrocarbon group is even more preferable.
The hydrocarbon group represented by ^R5 preferably has 1 to 10 carbon atoms, and more preferably has 3 to 8 carbon atoms.
As the polyfunctional (meth)acrylate of the lactone-modified polyhydric aliphatic alcohol, a compound represented by the following general formula (4) is more preferable.

（式（４）中、Ｙは、一般式（５）で表される構造を表す。式（５）中、Ｒ^９は、水素原子又はメチル基を表す。Ｒ^１０は、炭素数３～８の炭化水素基を表す。ｎは、１～３の整数を表す。）
上記炭素数３～８の炭化水素基は、炭素数３～８の二価の炭化水素基であることが好ましい。上記二価の炭化水素基は、二価の脂肪族炭化水素基であることが好ましく、アルキレン基であることがより好ましい。
上記二価の炭化水素基の炭素数は、３～７であることがより好ましい。
上記ラクトン変性多価脂肪族アルコールの多官能（メタ）アクリレートは、合成物であってもよいが、市販品を使用することもできる。上記ラクトン変性多価脂肪族アルコールの多官能（メタ）アクリレートの市販品としては、例えば、ＫＡＹＡＲＡＤ ＤＰＣＡ－６０、ＤＰＣＡ－１２０（いずれも日本化薬株式会社製）等が挙げられる。
本発明の感光性組成物は、上記ラクトン変性多価脂肪族アルコールの多官能（メタ）アクリレートを１種のみ含んでいてもよいし、２種以上含んでいてもよい。
上記ラクトン変性多価脂肪族アルコールの多官能（メタ）アクリレートの含有量は、感光性組成物１００質量％中３０質量％以上であることが好ましく、５０質量％以上であることがより好ましい。上記ラクトン変性多価脂肪族アルコールの多官能（メタ）アクリレートの含有量が３０質量％以上であり、後述する環化重合性モノマーとアシルフォスフィンオキサイド系光重合開始剤を更に含むと、本発明の感光性組成物は、弾性回復、硬度、密着性、及び耐久性により優れる硬化物を与えることができる。上記ラクトン変性多価脂肪族アルコールの多官能（メタ）アクリレートの含有量は、高弾性である点で、感光性組成物１００質量％中５５質量％以上であることが更に好ましく、６０質量％以上であることが特に好ましい。また、９７質量％以下であることが好ましく、９５質量％以下であることがより好ましく、９０質量％以下であることが更に好ましい。

(In formula (4), Y represents a structure represented by general formula (5). In formula (5), R ⁹ represents a hydrogen atom or a methyl group. R ¹⁰ represents a hydrocarbon group having 3 to 8 carbon atoms. n represents an integer of 1 to 3.)
The above-mentioned hydrocarbon group having 3 to 8 carbon atoms is preferably a divalent hydrocarbon group having 3 to 8 carbon atoms. The above-mentioned divalent hydrocarbon group is preferably a divalent aliphatic hydrocarbon group, and more preferably an alkylene group.
The divalent hydrocarbon group more preferably has 3 to 7 carbon atoms.
The polyfunctional (meth)acrylate of the lactone-modified polyhydric aliphatic alcohol may be a synthetic product, but a commercially available product may also be used. Examples of the commercially available polyfunctional (meth)acrylate of the lactone-modified polyhydric aliphatic alcohol include KAYARAD DPCA-60 and DPCA-120 (both manufactured by Nippon Kayaku Co., Ltd.).
The photosensitive composition of the present invention may contain only one type of polyfunctional (meth)acrylate of the lactone-modified polyhydric aliphatic alcohol, or may contain two or more types of such polyfunctional (meth)acrylate.
The content of the polyfunctional (meth)acrylate of the lactone-modified polyhydric aliphatic alcohol is preferably 30% by mass or more, more preferably 50% by mass or more, in 100% by mass of the photosensitive composition. When the content of the polyfunctional (meth)acrylate of the lactone-modified polyhydric aliphatic alcohol is 30% by mass or more and further contains a cyclopolymerizable monomer and an acylphosphine oxide-based photopolymerization initiator described later, the photosensitive composition of the present invention can provide a cured product having excellent elastic recovery, hardness, adhesion, and durability. The content of the polyfunctional (meth)acrylate of the lactone-modified polyhydric aliphatic alcohol is more preferably 55% by mass or more, particularly preferably 60% by mass or more, in terms of high elasticity, in 100% by mass of the photosensitive composition. In addition, it is preferably 97% by mass or less, more preferably 95% by mass or less, and even more preferably 90% by mass or less.

(B) Cyclopolymerizable Monomer The cyclopolymerizable monomer is a monomer having two or more radically polymerizable carbon-carbon double bonds in one molecule, and the double bonds form a ring structure in the molecule during radical polymerization. Specifically, at least one selected from the group consisting of acrylic ether dimers and α-(unsaturated alkoxyalkyl)acrylate monomers is preferred. Examples of acrylic ether dimers include compounds described in JP-A-2018-154720 (paragraph number 0027). Examples of α-(unsaturated alkoxyalkyl)acrylate monomers include alkyl-(α-methallyloxymethyl)acrylate and α-(allyloxymethyl)acrylate. Among them, α-(allyloxymethyl)acrylate (also referred to as α-allyloxymethylacrylic acid monomer in the present invention) is more preferred.
The photosensitive composition of the present invention may contain only one type of cyclopolymerizable monomer (B) such as the above-mentioned α-allyloxymethylacrylic acid monomer, or may contain two or more types.
The content of the cyclopolymerizable monomer (B) is preferably 60% by mass or less in 100% by mass of the photosensitive composition. When the content of the cyclopolymerizable monomer (B) is within the above range, the photosensitive composition of the present invention can provide a cured product having even better elastic recovery, hardness, adhesion, and durability. The content of the cyclopolymerizable monomer (B) is more preferably 50% by mass or less, and even more preferably 40% by mass or less in 100% by mass of the photosensitive composition in terms of high elasticity and high adhesion. The lower limit of the content of the cyclopolymerizable monomer (B) is not particularly limited, but is preferably 2% by mass or more, more preferably 5% by mass or more, and even more preferably 8% by mass or more.
In the photosensitive composition of the present invention, the mass ratio (A/B) of the polyfunctional (meth)acrylate of the lactone-modified polyhydric aliphatic alcohol (A) to the cyclopolymerizable monomer (B) is preferably 1/1 to 10/1. When the mass ratio is within the above range, high elasticity and high adhesion can be achieved at the same time. In terms of being able to exhibit higher elasticity, high adhesion, and durability, the mass ratio (A/B) is more preferably 1.5/1 or more, even more preferably 2/1 or more, and more preferably 9/1 or less.
As the above-mentioned α-(allyloxymethyl)acrylate, for example, a compound represented by the following formula (3) is preferable.

（式中、Ｒ^６は、水素原子又はメチル基、Ｒ^７は、水素原子又は１価の有機基を表す。）
上記式（３）で表される化合物（以下、ＡＭＡ単量体と称することもある。）であるが、該化合物は、（メタ）アクリル系単量体よりも、ラジカル硬化性が高く、硬化時の収縮が小さく、該化合物を硬化して得られる硬化物は優れた密着性、機械物性を有するものである。このような特徴は、本発明の組成物を用いて得られる硬化物の硬化収縮が低減され、密着性及び耐久性に優れる一因になると考えられる。
なお、本発明において、「硬化」とは、固化や架橋体の形成を意味するが、例えば粘着剤として有用な粘凋な液状物質（固体状でない物質）や、例えばコーティング材として有用な硬い固体状物質を形成することである。
ＡＭＡ単量体を硬化させて得られる硬化物は高い密着性を有することを確認しているが、これは環化重合で生じる下記式（６）；

(In the formula, ^R6 represents a hydrogen atom or a methyl group, and ^R7 represents a hydrogen atom or a monovalent organic group.)
The compound represented by the above formula (3) (hereinafter, sometimes referred to as AMA monomer) has higher radical curability and smaller shrinkage during curing than (meth)acrylic monomers, and the cured product obtained by curing the compound has excellent adhesion and mechanical properties. These characteristics are considered to be one of the reasons why the cured product obtained by using the composition of the present invention has reduced cure shrinkage and excellent adhesion and durability.
In the present invention, "hardening" means solidification or the formation of a crosslinked body, and refers to the formation of a viscous liquid substance (a non-solid substance) useful as an adhesive, or a hard solid substance useful as a coating material.
It has been confirmed that the cured product obtained by curing the AMA monomer has high adhesion, which is due to the following reaction product (6) that occurs during cyclopolymerization:

（式中、Ｒ^１１は、水素原子又はメチル基、Ｒ^１２は、水素原子又は１価の有機基を表す。）
で表される構造に含まれるテトラヒドロフラン環、及びテトラヒドロフラン環の両隣にあるメチレン基に起因すると考えられる。テトラヒドロフラン環は、いわゆるＬｅｗｉｓ塩基（孤立電子対の供与体）としての作用があり、テトラヒドロフラン環と基材表面の官能基とが相互作用しやすくなるため、良好な密着性を発現すると考えられる。テトラヒドロフラン環の両隣にあるメチレン基は、重合体鎖の柔軟性を向上させ、上記の相互作用がより効果的に生じると考えられる。さらに、α－アリルオキシメチルアクリル酸系単量体の硬化物は、耐熱性、相溶性、機械物性にも優れるが、これらの諸性能が発現する理由は、式（６）に示す構造に起因すると考えられる。

(In the formula, R ¹¹ represents a hydrogen atom or a methyl group, and R ¹² represents a hydrogen atom or a monovalent organic group.)
This is believed to be due to the tetrahydrofuran ring contained in the structure represented by the formula (6) and the methylene groups on both sides of the tetrahydrofuran ring. The tetrahydrofuran ring acts as a so-called Lewis base (lone pair donor), and is believed to facilitate interaction between the tetrahydrofuran ring and the functional group on the substrate surface, thereby exhibiting good adhesion. The methylene groups on both sides of the tetrahydrofuran ring are believed to improve the flexibility of the polymer chain, and the above-mentioned interaction is believed to occur more effectively. Furthermore, the cured product of the α-allyloxymethylacrylic acid monomer is also excellent in heat resistance, compatibility, and mechanical properties, and the reason why these various performances are exhibited is believed to be due to the structure represented by the formula (6).

The α-allyloxymethylacrylic acid monomer preferably has a boiling point of 95° C. or higher under 1333 Pa conditions. This means that the temperature at 1333 Pa in the vapor pressure curve of the α-allyloxymethylacrylic acid monomer is 95° C. or higher. It has been confirmed that there is a strong correlation between the boiling point and the curing property of the α-allyloxymethylacrylic acid monomer, and if the boiling point is 95° C. or higher under 1333 Pa conditions, the monomer will exhibit excellent curing property. Furthermore, by having such a boiling point, the α-allyloxymethylacrylic acid monomer will have excellent curing speed, surface curing property, and thin film curing property.
The boiling point of the α-allyloxymethylacrylic acid monomer under 1333 Pa conditions is more preferably 99° C. or higher, and even more preferably 103° C. or higher. Even if the boiling point at normal pressure calculated by the formula described in Japanese Patent No. 5591543 (paragraph 0025) is less than 205° C., the monomer may cure depending on the conditions, but in order to obtain good curability, a boiling point at normal pressure of 205° C. or higher is preferred. It is even more preferred to be 210° C. or higher, and most preferably 215° C. or higher.

^R7 in the above formula (3) represents a hydrogen atom or a monovalent organic group, which may be linear or branched, or may contain a cyclic structure.
The organic group is a monovalent organic group consisting of a hydrocarbon skeleton or a hydrocarbon skeleton containing an ether bond, and may have a substituent, i.e., at least a portion of the hydrogen atoms bonded to the carbon atoms constituting the hydrocarbon skeleton or the hydrocarbon skeleton containing an ether bond may be replaced with a substituent.
Examples of the monovalent organic group having a hydrocarbon skeleton include linear saturated hydrocarbon groups having 1 to 30 carbon atoms, linear unsaturated hydrocarbon groups having 1 to 30 carbon atoms, alicyclic hydrocarbon groups having 3 to 30 carbon atoms, and aromatic hydrocarbon groups having 6 to 30 carbon atoms. More preferred examples include linear saturated hydrocarbon groups having 1 to 10 carbon atoms, linear unsaturated hydrocarbon groups having 1 to 10 carbon atoms, alicyclic hydrocarbon groups having 4 to 25 carbon atoms, and aromatic hydrocarbon groups having 6 to 25 carbon atoms.
Examples of the monovalent organic group having a hydrocarbon skeleton containing an ether bond include those having a structure in which an oxygen atom is inserted into at least one carbon-carbon bond constituting the chain saturated hydrocarbon group, chain unsaturated hydrocarbon group, alicyclic hydrocarbon group, and aromatic hydrocarbon group.
Examples of the substituent include halogen atoms such as a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, a cyano group, and a trimethylsilyl group.

The chain saturated hydrocarbon group is not particularly limited as long as it is a linear or branched hydrocarbon group, and suitable examples thereof include n-butyl, n-amyl, s-amyl, t-amyl, neopentyl, n-hexyl, s-hexyl, n-heptyl, n-octyl, s-octyl, t-octyl, 2-ethylhexyl, capryl, nonyl, decyl, undecyl, lauryl, tridecyl, myristyl, pentadecyl, cetyl, heptadecyl, stearyl, nonadecyl, eicosyl, seryl, and melissyl groups.
Furthermore, at least a portion of the hydrogen atoms bonded to the carbon atoms constituting the chain saturated hydrocarbon group may be substituted with halogen atoms, cyano groups, or the like.
The chain unsaturated hydrocarbon group is not particularly limited as long as it is a linear or branched hydrocarbon group containing at least one non-aromatic carbon-carbon unsaturated bond, and suitable examples thereof include crotyl, 1,1-dimethyl-2-propenyl, 2-methyl-butenyl, 3-methyl-2-butenyl, 3-methyl-3-butenyl, 2-methyl-3-butenyl, oleyl, linole, linolene, and the like.
The alicyclic hydrocarbon group is not particularly limited as long as it is a hydrocarbon group containing a saturated cyclic structure of three or more members, or a non-aromatic unsaturated cyclic structure. Preferred examples of the alicyclic hydrocarbon group include cyclopentyl, cyclopentylmethyl, cyclohexyl, cyclohexylmethyl, 4-methylcyclohexyl, 4-t-butylcyclohexyl, tricyclodecanyl, isobornyl, adamantyl, dicyclopentanyl, and dicyclopentenyl groups.
The aromatic hydrocarbon group is not particularly limited as long as it is a hydrocarbon group containing a cyclic structure having aromatic properties with six or more members, and suitable examples thereof include phenyl, methylphenyl, dimethylphenyl, trimethylphenyl, 4-t-butylphenyl, benzyl, diphenylmethyl, diphenylethyl, triphenylmethyl, cinnamyl, naphthyl, anthranyl, and other groups.
The monovalent organic group having a hydrocarbon skeleton containing an ether bond may be any one having a structure in which an oxygen atom is inserted into at least one carbon-carbon bond constituting the chain saturated hydrocarbon group, chain unsaturated hydrocarbon group, alicyclic hydrocarbon group, or aromatic hydrocarbon group, and is not particularly limited. Examples of the monovalent organic group include chain ether groups such as methoxyethyl, methoxyethoxyethyl, methoxyethoxyethoxyethyl, 3-methoxybutyl, ethoxyethyl, and ethoxyethoxyethyl; cyclopentoxyethyl, cyclohexyloxyethyl, cyclopentoxyethoxyethyl, and cyclohexyloxyethoxyethyl; Preferred examples of the aryl ether groups include groups having both an alicyclic hydrocarbon group and a chain ether group, such as oxyethyl and dicyclopentenyloxyethyl; groups having both an aromatic hydrocarbon group and a chain ether group, such as phenoxyethyl and phenoxyethoxyethyl; and cyclic ether groups, such as glycidyl, β-methylglycidyl, β-ethylglycidyl, 3,4-epoxycyclohexylmethyl, 2-oxetanemethyl, 3-methyl-3-oxetanemethyl, 3-ethyl-3-oxetanemethyl, tetrahydrofuranyl, tetrahydrofurfuryl, tetrahydropyranyl, dioxazolanyl, and dioxanyl.

Examples of α-allyloxymethylacrylic acid monomers by compound name include α-allyloxymethylacrylic acid, methyl α-allyloxymethylacrylate, ethyl α-allyloxymethylacrylate, n-propyl α-allyloxymethylacrylate, isopropyl α-allyloxymethylacrylate, n-butyl α-allyloxymethylacrylate, n-amyl α-allyloxymethylacrylate, s-amyl α-allyloxymethylacrylate, t-amyl α-allyloxymethylacrylate, neopentyl α-allyloxymethylacrylate, n-hexyl α-allyloxymethylacrylate, and α-allyloxymethyl. α-allyloxymethylacrylate, s-hexyl α-allyloxymethylacrylate, n-heptyl α-allyloxymethylacrylate, n-octyl α-allyloxymethylacrylate, s-octyl α-allyloxymethylacrylate, t-octyl α-allyloxymethylacrylate, 2-ethylhexyl α-allyloxymethylacrylate, capryl α-allyloxymethylacrylate, nonyl α-allyloxymethylacrylate, decyl α-allyloxymethylacrylate, undecyl α-allyloxymethylacrylate, lauryl α-allyloxymethylacrylate, tridecyl α-allyloxymethylacrylate, myristyl α-allyloxymethylacrylate, -Allyloxymethylacrylic acid pentadecyl, α-allyloxymethylacrylic acid cetyl, α-allyloxymethylacrylic acid heptadecyl, α-allyloxymethylacrylic acid stearyl, α-allyloxymethylacrylic acid nonadecyl, α-allyloxymethylacrylic acid eicosyl, α-allyloxymethylacrylic acid ceryl, α-allyloxymethylacrylic acid melissyl, α-allyloxymethylacrylic acid crotyl, α-allyloxymethylacrylic acid 1,1-dimethyl-2-propenyl, α-allyloxymethylacrylic acid 2-methylbutenyl, α-allyloxymethylacrylic acid 3-methyl-2-butenyl , 3-methyl-3-butenyl α-allyloxymethylacrylate, 2-methyl-3-butenyl α-allyloxymethylacrylate, oleyl α-allyloxymethylacrylate, linoleyl α-allyloxymethylacrylate, linolene α-allyloxymethylacrylate, cyclopentyl α-allyloxymethylacrylate, cyclopentylmethyl α-allyloxymethylacrylate, cyclohexyl α-allyloxymethylacrylate, cyclohexylmethyl α-allyloxymethylacrylate, 4-methylcyclohexyl α-allyloxymethylacrylate, 4-t-butylcyclohexyl α-allyloxymethylacrylate α-allyloxymethylacrylate, tricyclodecanyl α-allyloxymethylacrylate, isobornyl α-allyloxymethylacrylate, adamantyl α-allyloxymethylacrylate, dicyclopentanyl α-allyloxymethylacrylate, dicyclopentenyl α-allyloxymethylacrylate, phenyl α-allyloxymethylacrylate, methylphenyl α-allyloxymethylacrylate, dimethylphenyl α-allyloxymethylacrylate, trimethylphenyl α-allyloxymethylacrylate, 4-t-butylphenyl α-allyloxymethylacrylate, benzyl α-allyloxymethylacrylate, α-allyloxymethylacrylate, 4-t-butylphenyl α-allyloxymethylacrylate, benzyl α-allyloxymethylacrylate, diphenylmethyl acrylate, diphenylethyl α-allyloxymethylacrylate, triphenylmethyl α-allyloxymethylacrylate, cinnamyl α-allyloxymethylacrylate, naphthyl α-allyloxymethylacrylate, anthranyl α-allyloxymethylacrylate, methoxyethyl α-allyloxymethylacrylate, methoxyethoxyethyl α-allyloxymethylacrylate, methoxyethoxyethoxyethyl α-allyloxymethylacrylate, 3-methoxybutyl α-allyloxymethylacrylate, ethoxyethyl α-allyloxymethylacrylate, Ethoxyethoxyethyl acrylate, cyclopentoxyethyl α-allyloxymethylacrylate, cyclohexyloxyethyl α-allyloxymethylacrylate, cyclopentoxyethoxyethyl α-allyloxymethylacrylate, cyclohexyloxyethoxyethyl α-allyloxymethylacrylate, dicyclopentenyloxyethyl α-allyloxymethylacrylate, phenoxyethyl α-allyloxymethylacrylate, phenoxyethoxyethyl α-allyloxymethylacrylate, glycidyl α-allyloxymethylacrylate, β-methylglycidyl α-allyloxymethylacrylate, Preferred examples thereof include β-ethylglycidyl α-allyloxymethylacrylate, 3,4-epoxycyclohexylmethyl α-allyloxymethylacrylate, 2-oxetanemethyl α-allyloxymethylacrylate, 3-methyl-3-oxetanemethyl α-allyloxymethylacrylate, 3-ethyl-3-oxetanemethyl α-allyloxymethylacrylate, tetrahydrofuranyl α-allyloxymethylacrylate, tetrahydrofurfuryl α-allyloxymethylacrylate, tetrahydropyranyl α-allyloxymethylacrylate, dioxazolanyl, and dioxanyl α-allyloxymethylacrylate.
In particular, methyl α-allyloxymethylacrylate, ethyl α-allyloxymethylacrylate, n-propyl α-allyloxymethylacrylate, isopropyl α-allyloxymethylacrylate, n-butyl α-allyloxymethylacrylate, sec-butyl α-allyloxymethylacrylate, tert-butyl α-allyloxymethylacrylate, cyclohexyl α-allyloxymethylacrylate, allyl α-allyloxymethylacrylate, methallyl α-allyloxymethylacrylate, crotyl α-allyloxymethylacrylate, methoxyethyl α-allyloxymethylacrylate, ethoxyethyl α-allyloxymethylacrylate, α-allyloxymethyl acrylate, methallyl α-allyloxymethylacrylate, crotyl α-allyloxymethylacrylate, methoxyethyl α-allyloxymethylacrylate, ethoxyethyl α-allyloxymethylacrylate, methallyl ... Glycidyl acrylate and vinyloxyethyl α-allyloxymethylacrylate are more preferred, with methyl α-allyloxymethylacrylate, ethyl α-allyloxymethylacrylate, n-propyl α-allyloxymethylacrylate, isopropyl α-allyloxymethylacrylate, n-butyl α-allyloxymethylacrylate, sec-butyl α-allyloxymethylacrylate, tert-butyl α-allyloxymethylacrylate and cyclohexyl α-allyloxymethylacrylate being even more preferred, and methyl α-allyloxymethylacrylate, ethyl α-allyloxymethylacrylate and cyclohexyl α-allyloxymethylacrylate being particularly preferred.
Therefore, ^R7 in the above formula (3) is preferably a hydrocarbon group having 1 to 10 carbon atoms which may have a substituent. The hydrocarbon group having 1 to 10 carbon atoms may be linear, branched, or cyclic, and may contain an ether bond.

Examples of a method for producing α-allyloxymethylacrylic acid monomers include the method described in Japanese Patent No. 5,591,543 (paragraphs 0037 to 0040).

(C) Acylphosphine Oxide Photopolymerization Initiator The photosensitive composition of the present invention further contains an acylphosphine oxide photopolymerization initiator.
By combining the above-mentioned components (A) and (B) with an acylphosphine oxide-based photopolymerization initiator, the photosensitive composition can have good curability and give a cured product excellent in elastic recovery rate, hardness, adhesion, and durability.

Examples of the acylphosphine oxide photopolymerization initiator include monoacylphosphine oxide photopolymerization initiators such as 2,4,6-trimethylbenzoyl-diphenylphosphine oxide and 2,4,6-trimethylbenzoyl-ethyl-phenyl-phosphinate; bis-(2,6-dichlorobenzoyl)phenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-2,5-dimethylphenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-4-propylphenylphosphine oxide, and bis-(2,6-dichlorobenzoyl)-4-propylphenylphosphine oxide. )-1-naphthylphosphine oxide, bis-(2,6-dimethoxybenzoyl)phenylphosphine oxide, bis-(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, bis-(2,6-dimethoxybenzoyl)-2,5-dimethylphenylphosphine oxide, bis-(2,4,6-trimethylbenzoyl)phenylphosphine oxide, (2,5,6-trimethylbenzoyl)-2,4,4-trimethylpentylphosphine oxide, and other bisacylphosphine oxide photopolymerization initiators.
Among these, the acylphosphine oxide-based photopolymerization initiators are particularly preferred in terms of their high activity, including 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2,4,6-trimethylbenzoyl-ethyl-phenyl-phosphinate, bis-(2,6-dimethoxybenzoyl)phenylphosphine oxide, bis-(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, bis-(2,4,6-trimethylbenzoyl)phenylphosphine oxide, (2,5,6-trimethylbenzoyl)-2,4,4-trimethylpentylphosphine oxide, and bis-(2,5,6-trimethylbenzoyl)-2,4,4-trimethylpentylphosphine oxide. Preferably, it is 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2,4,6-trimethylbenzoyl-ethyl-phenyl-phosphinate, bis-(2,6-dimethoxybenzoyl)phenylphosphine oxide, bis-(2,4,6-trimethylbenzoyl)phenylphosphine oxide, more preferably, it is 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, bis-(2,4,6-trimethylbenzoyl)phenylphosphine oxide, further preferably.
The photosensitive composition may contain only one type of the acylphosphine oxide-based photopolymerization initiator, or may contain two or more types of the acylphosphine oxide-based photopolymerization initiator.
The content of the acylphosphine oxide-based photopolymerization initiator is preferably 0.1 to 2% by mass in 100% by mass of the photosensitive composition. When the content of the photopolymerization initiator is within the above-mentioned range, the photosensitive composition of the present invention can provide a cured product having even better elastic recovery, hardness, adhesion, and durability. In terms of high sensitivity, the content of the photopolymerization initiator is more preferably 0.2% by mass or more, even more preferably 0.5% by mass or more, more preferably 1.8% by mass or less, and even more preferably 1.5% by mass or less.

(D) Polymerization Inhibitor The photosensitive composition of the present invention may further contain a polymerization inhibitor. By further containing a polymerization inhibitor, the adhesion can be further improved. In addition, the storage stability of the photosensitive composition can be improved.
The polymerization inhibitor is not particularly limited, and known ones can be used. For example, benzoquinone, hydroquinones (e.g., hydroquinone, hydroquinone monomethyl ether, p-tert-butylhydroquinone, p-benzoquinone, etc.), phenols (e.g., 2,6-di-t-butyl-4-methylphenol, 6-t-butyl-2,4-dimethylphenol, 2,2'-methylenebis(4-methyl-6-t-butylphenol)), catechols (e.g., p-tert-butylcatechol, etc.), amines (e.g., N,N-diethylhydroxylamine, etc.), 1,1-diphenyl-2-picrylhydrazyl, tri-p-nitrophenylmethyl, phenothiazine, piperidine 1-oxyls (e.g., 2,2,6,6-tetramethylpiperidine 1-oxyl, 4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxyl, etc.), and the like can be mentioned.
Among these, in terms of high solubility, benzoquinone, hydroquinones, phenols, amines, and piperidine 1-oxyls are preferred, benzoquinone, hydroquinones, phenols, and piperidine 1-oxyls are more preferred, and phenols and piperidine 1-oxyls are even more preferred.
The photosensitive composition may contain only one type of the polymerization inhibitor, or may contain two or more types of the polymerization inhibitor.
The content of the polymerization inhibitor is preferably 0.01 to 2% by mass in 100% by mass of the photosensitive composition. In terms of high curing, the content of the polymerization inhibitor is more preferably 0.02% by mass or more, even more preferably 0.05% by mass or more, more preferably 1.5% by mass or less, and even more preferably 1% by mass or less in 100% by mass of the photosensitive composition.

(E) Alicyclic Monofunctional (meth)acrylate The above alicyclic monofunctional (meth)acrylate is a monofunctional (meth)acrylate having an alicyclic hydrocarbon group and one (meth)acryloyl group in the molecule.
Examples of the alicyclic hydrocarbon group include monocyclic hydrocarbon groups such as cyclopropyl, cyclopentyl, cyclohexyl, cyclooctyl, cyclododecyl, cycloheptyl, cyclobutenyl, cyclopentenyl, cyclohexenyl, etc., and polycyclic hydrocarbon groups such as dicyclopentanyl, dicyclopentenyl, tricyclodecanyl, adamantyl, isobornyl, etc. Among these, polycyclic hydrocarbon groups are preferred in that they can further improve the elastic recovery, hardness, and adhesion of the cured product of the photosensitive composition.
The alicyclic hydrocarbon group may be one in which at least one carbon atom constituting the alicyclic hydrocarbon group is substituted with an oxygen atom, a nitrogen atom, a sulfur atom, or the like, or at least one hydrogen atom constituting the hydrocarbon group may be substituted with a hydroxyl group, an alkyl group, an alkoxyl group, or the like.
The number of carbon atoms in the alicyclic hydrocarbon group is preferably 6 or more, more preferably 7 or more, and even more preferably 8 or more, in order to prevent cure shrinkage of the photosensitive composition and further improve adhesion. Moreover, the number of carbon atoms in the alicyclic hydrocarbon group is preferably 20 or less, more preferably 18 or less, and even more preferably 15 or less, in order not to inhibit the reaction of the double bond due to steric hindrance.
The alicyclic monofunctional (meth)acrylate preferably has a glass transition temperature (Tg) of 100° C. or higher in the form of a homopolymer.
When an alicyclic monofunctional (meth)acrylate having a homopolymer glass transition temperature of 100° C. or higher is used, heat resistance is improved, cure shrinkage can be prevented, and adhesion can be further improved.
The alicyclic monofunctional (meth)acrylate more preferably has a homopolymer glass transition temperature (Tg) of 120° C. or higher. The upper limit of the glass transition temperature (Tg) of the homopolymer is not particularly limited, but is preferably 200° C. or lower in terms of imparting flexibility.
The glass transition temperature (Tg) of the homopolymer may be any of those described in POLYMER HANDBOOK (Polymer Handbook, 4th Edition, Wiley Interscience, Chapter 6, page 200, etc.), J. Brandrup, E. H. Immergut, Polymer Handbook, 2nd Ed., J. Wiley, New York 1975, and Photocuring Technology Data Book (Techno Net Books Co., Ltd.).
Specific examples of the alicyclic monofunctional (meth)acrylate include cyclohexyl (meth)acrylate, cyclohexylmethyl (meth)acrylate, isobornyl (meth)acrylate, 1-adamantyl (meth)acrylate, (3,4-epoxycyclohexyl)methyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, and tricyclodecanyl (meth)acrylate.
Among these, in terms of high glass transition temperature and resistance to elimination of alicyclic hydrocarbons, the alicyclic monofunctional (meth)acrylate is preferably cyclohexyl (meth)acrylate, cyclohexylmethyl (meth)acrylate, isobornyl (meth)acrylate, 1-adamantyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, or tricyclodecanyl (meth)acrylate, more preferably cyclohexyl (meth)acrylate, cyclohexylmethyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, or dicyclopentenyl (meth)acrylate, and even more preferably isobornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, or dicyclopentanyl (meth)acrylate.
The photosensitive composition may contain only one type of the alicyclic monofunctional (meth)acrylate, or may contain two or more types of the alicyclic monofunctional (meth)acrylate.
The content of the alicyclic monofunctional (meth)acrylate is preferably 40% by mass or less in 100% by mass of the photosensitive composition. When the content of the alicyclic monofunctional (meth)acrylate is within the above range, the photosensitive composition of the present invention can provide a cured product having even better elastic recovery, hardness, and adhesion. The content of the alicyclic monofunctional (meth)acrylate is more preferably 30% by mass or less in 100% by mass of the photosensitive composition, more preferably 20% by mass or less, particularly preferably 15% by mass or less, and most preferably 10% by mass or less, in terms of high elasticity and high adhesion. The lower limit of the content of the alicyclic monofunctional (meth)acrylate is not particularly limited, but is preferably 2% by mass or more.

(F) Other Components The photosensitive composition of the present invention may contain other components, if necessary, in addition to the components described above. Examples of the other components include polymerizable compounds other than the above-mentioned (meth)acrylates; examples of the other polymerizable compounds include other alicyclic (meth)acrylates such as tetrahydrofurfuryl (meth)acrylate, (2-methyl-2-ethyl-1,3-dioxolan-4-yl)methyl (meth)acrylate, 3,3,5-trimethylcyclohexyl (meth)acrylate, and (3-ethyloxetan-3-yl)methyl methacrylate; linear alkyl (meth)acrylates such as methyl (meth)acrylate; vinyl ether (meth)acrylates such as 2-(2-vinyloxyethoxy)ethyl (meth)acrylate; bifunctional (meth)acrylates such as 1,6-hexanediol di(meth)acrylate and dimethylol-tricyclodecane di(meth)acrylate; and trifunctional (meth)acrylates such as trimethylolpropane tri(meth)acrylate and pentaerythritol tri(meth)acrylate.
The content of the monofunctional (meth)acrylate or polyfunctional (meth)acrylate is preferably 40 mass % or less, more preferably 30 mass % or less, particularly preferably 20 mass % or less, and most preferably 10 mass % or less, relative to 100 mass % of the photosensitive composition, in terms of high elasticity, high adhesion, and high durability (high reliability).

Other examples of the components include the following: resin; solvent; colorant; dispersant; heat resistance improver; leveling agent; development aid; inorganic fine particles such as silica fine particles; coupling agents such as silane-based, aluminum-based, and titanium-based; filler; curing aid; plasticizer; ultraviolet absorber; antioxidant; matting agent; defoaming agent; antistatic agent; slip agent; surface modifier; thixotropic agent; thixotropic aid; acid generator; photosensitizer; photoradical polymerization accelerator; surfactant; and the like. The photosensitive composition may contain only one of these components, or may contain two or more of them. These components can be appropriately selected from known ones and used. The amount of use can also be appropriately set. For example, it is preferably 20% by mass or less, and more preferably 10% by mass or less, in 100% by mass of the photosensitive composition. The lower limit is not particularly limited, but is preferably 0% by mass or more, and more preferably 1% by mass or more.
The photosensitive composition of the present invention may contain a solvent, but is preferably substantially free of solvent, since there is a risk that polymerizable compounds such as (meth)acrylates may also be evaporated when the solvent is evaporated. The content of the solvent in the photosensitive composition is preferably 3% by mass or less, more preferably 2% by mass or less, and even more preferably 1% by mass or less, based on 100% by mass of the photosensitive composition.
The solvent includes those that are commonly used in photosensitive compositions, and may be appropriately selected depending on the purpose and application, and is not particularly limited, and examples thereof include ethers such as tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, etc.; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc.; esters such as ethyl acetate, butyl acetate, propylene glycol monomethyl ether acetate, 3-methoxybutyl acetate, etc.; alcohols such as methanol, ethanol, isopropanol, n-butanol, ethylene glycol monomethyl ether, propylene glycol monomethyl ether, etc.; aromatic hydrocarbons such as toluene, xylene, ethylbenzene, etc.; chloroform; dimethyl sulfoxide; and various organic solvents such as water, etc. The photosensitive composition may contain only one type of solvent, or may contain two or more types.
The photosensitive composition of the present invention may contain a colorant, but is preferably substantially free of a colorant in terms of reduced curability. The content of the colorant in the photosensitive composition is preferably 3% by mass or less, more preferably 2% by mass or less, and even more preferably 1% by mass or less, based on 100% by mass of the photosensitive composition.
The colorant is not particularly limited, and examples thereof include known pigments and dyes that are commonly used as colorants.

(Method of preparing photosensitive composition)
The method for preparing the photosensitive composition of the present invention is not particularly limited, and may be a known method, for example, a method in which the above-mentioned components are mixed and dispersed using a known mixer or disperser. The mixing and dispersion process is not particularly limited, and may be performed by a known method.
(Method of curing photosensitive composition)
The method for curing the photosensitive composition of the present invention is not particularly limited, and any known method may be used. Examples of the method include a method of applying the photosensitive composition onto a substrate to form a coating film, and then irradiating the coating film with active energy rays to form a coating film, and a method of molding the photosensitive composition into a desired shape, and then irradiating the molded product with active energy rays to obtain a cured molded product.
The coating method is not particularly limited, and examples thereof include known coating methods such as spin coating, slit coating, roll coating, and cast coating.
The molding method is not particularly limited, and examples thereof include known molding methods such as injection molding, blow molding, extrusion molding, vacuum molding, compression molding, and press molding.
The active energy rays may be an electron beam, ultraviolet light, or visible light.The light source may be a thermionic emission gun, a field emission gun, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a metal halide lamp, a gallium lamp, a xenon lamp, a carbon arc lamp, an LED, or the like.
The amount of active energy radiation to be irradiated is not particularly limited and can be appropriately set depending on the purpose and use of the photosensitive composition, the amount of the photopolymerization initiator, and the like. For example, the amount is preferably 10 to 10,000 mJ/ ^cm2 , more preferably 20 to 9,000 mJ/ ^cm2 , and still more preferably 30 to 8,000 mJ/ ^cm2 .
The curing method may also include a heating step as necessary. For example, a heating step may be performed before or after the active energy ray irradiation step, or both before and after the active energy ray irradiation step. For example, when the photosensitive composition contains a volatile component such as a solvent, a heating (drying) step may be performed to remove the volatile component. In addition, after the active energy ray irradiation to the photosensitive composition, a heating step may be performed as a post-curing step.
The heating conditions are not particularly limited and can be appropriately set from known methods depending on the purpose and use of the photosensitive composition. When the heating step is performed multiple times, the heating conditions for each step may be the same or different.
When the cured product obtained by curing the photosensitive composition of the present invention is a cured film, its film thickness is preferably 5 μm or more. When the film thickness is 5 μm or more, it can exhibit even better elastic recovery, hardness, adhesion, and durability. The film thickness is more preferably 7 μm or more, and even more preferably 10 μm or more. The upper limit of the film thickness is not particularly limited and may be appropriately set according to the purpose and use of the cured film, but for example, it is more preferably 1000 μm or less, and even more preferably 800 μm or less.
The cured product obtained by curing the photosensitive composition of the present invention preferably has an elastic recovery of 85% or more, more preferably 86% or more, and even more preferably 90% or more. A high elastic recovery rate leads to better elastic recovery, and for example, the self-repairing ability of the cured product when it is scratched is improved.
The elastic recovery rate can be determined by measurement using a microcompression tester, specifically, by the method described in the examples below.
The cured product obtained by curing the photosensitive composition of the present invention preferably has a pencil hardness of 3H or more, and more preferably 4H or more. The pencil hardness can be determined by a method in accordance with JIS-K5600-5-4 (1999), and specifically, can be determined by the method described in the examples below.
The cured product obtained by curing the photosensitive composition of the present invention preferably has a rating of 3 or more, more preferably a rating of 2 or more, and even more preferably a rating of 1 or more, in an adhesion test by a cross-cut method determined by a method in accordance with JIS-K5600-5-6 (1999). The adhesion test by the cross-cut method can be specifically carried out by the method described in the examples below.

(Application)
The photosensitive composition of the present invention can provide a cured product having excellent elastic recovery, hardness, adhesion, and durability. Therefore, the photosensitive composition of the present invention can be suitably used in applications requiring excellent elastic recovery, adhesion, and high hardness. The photosensitive composition of the present invention can be a photosensitive composition suitable for, for example, hard coats, overcoats, optical films, adhesives, sealants, insulating films, optical filters used as near-infrared or infrared cut filters, and the like.
As described above, the cured product obtained by curing the photosensitive composition of the present invention is excellent in elastic recovery, hardness, adhesion, and durability, and can be suitably used in various applications such as hard coats, overcoats, optical films, adhesives, sealants, insulating films, and optical filters used as near-infrared or infrared cut filters.

The present invention will be described in more detail below with reference to examples. However, the following examples do not limit the present invention, and all modifications and variations within the scope of the present invention are included in the technical scope of the present invention.
In the examples and comparative examples, unless otherwise specified, "%" means "% by mass" and "parts" means "parts by mass".
In the present examples, each evaluation was carried out by the following methods.
(1) Adhesion: The photosensitive composition was applied onto a 10 cm square glass substrate using a spin coater. The applied film was irradiated with ultraviolet light at an intensity of 1 J/ ^cm2 (converted to 365 nm illuminance) using a UV aligner (TME-150RNS, manufactured by TOPCON) equipped with a 2.0 kW ultra-high pressure mercury lamp to obtain a cured film (film thickness 500 μm). The obtained cured film was subjected to JIS K5600-5-6:1999 "General test method for paints - Part 5: Mechanical properties of coating film - Section 6: Adhesion (cross-cut method)". The film remaining rate was rated as 1 when it was 100 to 95%, 2 when it was 95 to 85%, 3 when it was 85 to 65%, 4 when it was 65 to 35%, and 5 when it was less than 35%. The evaluation results are shown in Table 1.
(2) Hardness (pencil hardness)
The photosensitive composition was applied onto a 10 cm square glass substrate using a spin coater. The applied film was irradiated with ultraviolet light at an intensity of 1 J/ ^cm2 (converted to 365 nm illuminance) using a UV aligner (TME-150RNS, manufactured by TOPCON Corporation) equipped with a 2.0 kW ultra-high pressure mercury lamp to obtain a cured film (film thickness 500 μm). The obtained cured film was subjected to a pencil hardness test in accordance with JIS-K5600-5-4 (1999). In the pencil hardness test, the load was always 500 g according to the old JIS version of JIS-K5400 (1990), and the hardest pencil that did not produce a scratch was taken as the hardness (surface hardness) value.
(3) Elastic recovery rate: The photosensitive composition was applied onto a 10 cm square glass substrate using a spin coater. The applied film was irradiated with ultraviolet light at an intensity of 1 J/ ^cm2 (365 nm illuminance equivalent) using a UV aligner (TME-150RNS, manufactured by TOPCON) equipped with a 2.0 kW ultra-high pressure mercury lamp to obtain a cured film. The elastic recovery rate of the obtained cured film was measured using a microcompression tester (product name: HM2000, manufactured by Fisher Instruments). A load of up to 80 mN was applied using a 100 μm square flat indenter at a loading rate and unloading rate of 4.7 mN/sec, and then the load was unloaded to 0.49 mN, to create a load-deformation curve during loading and a load-deformation curve during unloading. At this time, the deformation amount at a load of 80 mN during loading was defined as L1, and the deformation amount at a load of 0.49 mN during unloading was defined as L2, and the elastic recovery rate was calculated by the following formula.
Elastic recovery rate (%) = (L1 - L2) x 100 / L1

(4) Durability (reliability)
4-1. Preparation of a sample for reliability evaluation A photosensitive composition was applied to a 10 cm square glass substrate using a spin coater, and the coating film was developed by irradiating ultraviolet light at an intensity of 1 J/ ^cm2 (equivalent to 365 nm illuminance) using a UV aligner (TME-150RNS, manufactured by TOPCON) equipped with a 2.0 kW ultra-high pressure mercury lamp, and then heated for 10 minutes in a 100°C oven (PHH-201, manufactured by ESPEC). On this cured product, a titanium oxide 2-layer/silica 3-layer alternate deposition film (visible light antireflection film) was formed by ion-assisted electron beam deposition using a high-speed IAD vacuum thin film forming device (Shincron, BIS-1300D). The acceleration voltage for the first and second layers was 500 V, and the acceleration voltage for the third layer and after was 800 V.
4-2. High temperature and high humidity test (THS)
The above cured substrate (reliability evaluation sample) was subjected to a 500-hour test in an environment of 85°C and 85% humidity using a thermohygrostat (PR-1K, manufactured by Espec Corporation). The appearance was observed every 50 hours and visually evaluated according to the following criteria.
○: No cracks were observed even after 150 hours or more. △: Cracks were observed after 100 hours. ×: Cracks were observed after 50 hours.
4-3. Thermal cycle test (TC)
The above cured substrate (reliability evaluation sample) was subjected to a thermal shock test using a thermal shock device (TSA-71S, manufactured by Espec Corp.), with one cycle consisting of 30 minutes at -40°C and 30 minutes at 85°C. The appearance was observed every 50 cycles and visually evaluated according to the following criteria.
◯: No cracks were observed even after 150 cycles or more. △: Cracks were observed after 100 cycles. ×: Cracks were observed after 50 cycles.
Examples 1 to 5, Comparative Examples 1 to 8
Photosensitive compositions were prepared by mixing various monofunctional monomers, polyfunctional monomers, photopolymerization initiators, and polymerization inhibitors in a paint shaker so as to obtain the compositions shown in Table 1. The components shown in Table 1 are as follows.
<Monofunctional Monomer>
AOMA: methyl α-allyloxymethylacrylate EtAOMA: ethyl α-allyloxymethylacrylate ChAOMA: hexyl α-allyloxymethylacrylate
513AS: Dicyclopentanyl acrylate EC-A: Ethoxydiethylene glycol acrylate MMA: Methyl methacrylate CHA: Cyclohexyl acrylate
<Polyfunctional Monomer>
DPCA-60: Polyacrylate of lactone-modified polyhydric aliphatic alcohol (6 mol of lactone added)
DPCA-120: Polyacrylate of lactone-modified polyhydric aliphatic alcohol (12 mol of lactone added) KAYARAD series manufactured by Nippon Kayaku DPHA: Dipentaerythritol hexaacrylate manufactured by Kyoeisha Chemical A-9300: Ethoxylated isocyanuric acid triacrylate manufactured by Shin-Nakamura Chemical UX-5000: Hexafunctional urethane acrylate manufactured by Nippon Kayaku <Photopolymerization initiator> All manufactured by BASF Omn 184: Omnirad 184 (α-hydroxyalkylphenone type)
1-Hydroxycyclohexyl phenyl ketone Omn TPO: Omnirad TPO H (Acylphosphine oxide type)
2,4,6-trimethylbenzoyl-diphenylphosphine oxide Omn 819: Omnirad 819 (acylphosphine oxide type)
Bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide Omn 907: Omnirad 907 (α-aminoalkylphenone type) 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one Irg OXE02: Irgacure OXE02 (N-oxime ester type) Ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(0-acetyloxime)
<Polymerization inhibitor>
W400: Kawaguchi Chemical Industry (Antage W400)
2,2'-methylenebis(4-methyl-6-t-butylphenol)
4HTEMPO: 4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxyl

表１より、ラクトン変性多価脂肪族アルコールの多官能（メタ）アクリレートと、環化重合性モノマーと、アシルフォスフィンオキサイド系光重合開始剤を含む実施例の感光性組成物は、弾性回復、硬度、密着性及び耐久性（信頼性）のいずれにも優れた硬化物を与えることがわかった。特に、比較例に比べて、実施例の感光性組成物は密着性（クロスカット）及び信頼性（THS、TC）で顕著な優位性を確認できた。また、実施例２～４のトータル性能を比較した場合、いずれもレベルは高いが、実施例４（α-アリルオキシメチルアクリル酸ヘキシル使用）のように、式（３）におけるＲ^７の疎水性が適度に高い環化重合性モノマーを使用することによる優位性を確認できた。

From Table 1, it was found that the photosensitive composition of the example containing the polyfunctional (meth)acrylate of lactone-modified polyhydric aliphatic alcohol, the cyclopolymerizable monomer, and the acylphosphine oxide-based photopolymerization initiator gave a cured product excellent in elastic recovery, hardness, adhesion, and durability (reliability). In particular, the photosensitive composition of the example was confirmed to have a remarkable superiority in adhesion (cross-cut) and reliability (THS, TC) compared to the comparative example. In addition, when comparing the total performance of Examples 2 to 4, all of them were at a high level, but the superiority of using a cyclopolymerizable monomer with a moderately high hydrophobicity of R ⁷ in formula (3) as in Example 4 (using α-allyloxymethyl hexyl acrylate) was confirmed.

The photosensitive composition of the present invention can be suitably used in applications requiring excellent elastic recovery, adhesion, and high hardness, such as hard coats, overcoats, optical films, adhesives, sealants, insulating films, and optical filters used as near-infrared or infrared cut filters.

Claims (9)

A photosensitive composition comprising a polyfunctional (meth)acrylate (A) of a lactone-modified polyhydric aliphatic alcohol, which is a compound represented by the following general formula (1), a cyclopolymerizable monomer (B), and an acylphosphine oxide-based photopolymerization initiator (C), wherein the content of the cyclopolymerizable monomer (B) is 8% by mass or more and 40% by mass or less in 100% by mass of the photosensitive composition:

In formula (1), R ¹ , R ² and R ³ are the same or different and represent an organic group. X represents a structure represented by general formula (2). a and c are the same or different and represent an integer of 0 to 3, b is an integer of 0 to 2 and satisfies a+b1+c≧6. 1 is an integer of 0 to 6.
In formula (2), R ⁴ represents a hydrogen atom or a methyl group. R ⁵ represents a hydrocarbon group having 1 to 8 carbon atoms. m represents an integer of 2 or 3. The photosensitive composition according to claim 1, characterized in that the content of the acylphosphine oxide-based photopolymerization initiator (C) is 0.1 to 2 mass % in 100 mass % of the photosensitive composition. The photosensitive composition according to claim 1 or 2, further comprising an alicyclic monofunctional (meth)acrylate (E). 3. The photosensitive composition according to claim 1, wherein the cyclopolymerizable monomer (B) is a compound represented by the following general formula (3) :

(In the formula, ^R6 represents a hydrogen atom or a methyl group, and ^R7 represents a hydrogen atom or a monovalent organic group.)
The photosensitive composition according to claim 1 or 2, characterized in that the content of the polyfunctional (meth)acrylate (A) of the lactone-modified polyhydric aliphatic alcohol is 30% by mass or more and 90% by mass or less in 100% by mass of the photosensitive composition. The photosensitive composition according to claim 3, characterized in that the content of the alicyclic monofunctional (meth)acrylate (E) is 2% by mass or more and 40% by mass or less in 100% by mass of the photosensitive composition. The photosensitive composition according to claim 1 or 2, further comprising a polymerization inhibitor (D). The photosensitive composition according to claim 1 or 2, characterized in that the content of the solvent in the photosensitive composition is 3% by mass or less based on 100% by mass of the photosensitive composition. The photosensitive composition according to claim 1 or 2, characterized in that the content of the colorant in the photosensitive composition is 3% by mass or less based on 100% by mass of the photosensitive composition.