JP7586641B2 - 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 with excellent elastic recovery, adhesion, and hardness.

Photosensitive compositions that can react and harden when exposed to light are being considered for use in a variety of applications, such as color filters used in liquid crystal display devices, photoresists, inks, hard coats, optical films, and other various optical components, as well as electrical and electronic devices, and resin compositions with excellent properties required for each application are being developed.
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, based on 100 mass % of a radically polymerizable compound, 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, as a coating composition that is excellent in reactivity to active energy rays and can form a cured coating film having excellent weather resistance and abrasion resistance.

For example, Patent Document 2 discloses a photosensitive resin composition that contains a photopolymerizable compound containing at least one of a photopolymerizable monomer and a photopolymerizable oligomer, titanium oxide, and a polymerization initiator, and the polymerization initiator contains an acylphosphine oxide-based polymerization initiator and a phenylglyoxylate-based polymerization initiator. Patent Document 3 discloses an active energy ray-curable coating resin composition that contains a (meth)acrylate compound having a ring-opened structure of ε-caprolactone, and a phosphate ester compound having a hydrocarbon group with 8 or more carbon atoms and an ethylene oxide group.

For example, Patent Document 4 describes an active energy ray curable composition that has excellent releasability from a mold after curing and excellent water resistance, and that contains 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. Patent Document 5 describes a radically polymerizable ink composition that contains a monofunctional radically polymerizable unsaturated compound, a polyfunctional radically polymerizable unsaturated compound, a specific polymerization initiator, and a colorant.

Patent No. 5283485 Patent No. 5997852 Patent No. 6370748 JP 2019-94484 A Patent No. 6555910

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.
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, and adhesion to a substrate.

The present invention was made in consideration of the above-mentioned current situation, and aims to provide a photosensitive composition that can give a cured product with excellent elastic recovery, hardness, and adhesion.

The inventors conducted extensive research into photosensitive resin compositions and discovered that by including a specific polyfunctional (meth)acrylate, an alicyclic monofunctional (meth)acrylate, and a specific photopolymerization initiator, it is possible to obtain a cured product with excellent elastic recovery, hardness, and adhesion, which led to the completion of the present invention.

That is, the present invention is a photosensitive composition that contains a polyfunctional (meth)acrylate of a lactone-modified polyhydric aliphatic alcohol (A), an alicyclic monofunctional (meth)acrylate (B), and an acylphosphine oxide-based photopolymerization initiator (C), and is characterized in that the content of the polyfunctional (meth)acrylate of the lactone-modified polyhydric aliphatic alcohol (A) is 50% by mass or more in 100% by mass of the photosensitive composition.

The polyfunctional (meth)acrylate (A) of the lactone-modified polyhydric aliphatic alcohol is preferably a compound represented by the following general formula (1):

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.

The mass ratio (A/B) of the polyfunctional (meth)acrylate (A) of the lactone-modified polyhydric aliphatic alcohol to the alicyclic monofunctional (meth)acrylate (B) is preferably 1/1 to 10/1.

The content of the alicyclic monofunctional (meth)acrylate (B) is preferably 49.9% by mass or less in 100% by mass of the photosensitive composition.

The content of the acylphosphine oxide photopolymerization initiator (C) is preferably 0.1 to 2% by mass based on 100% by mass of the photosensitive composition.

The photosensitive composition preferably further contains a polymerization inhibitor (D).

The photosensitive composition preferably contains no more than 3% by mass of the solvent relative to 100% by mass of the photosensitive composition.

The photosensitive composition preferably contains a colorant in an amount of 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 with excellent elastic recovery, hardness, and adhesion. The photosensitive composition of the present invention can be used in a variety of applications, such as hard coats, overcoats, optical films, adhesives, sealants, and insulating films.

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)acrylate" means "acrylate and/or methacrylate", and "(meth)acrylic acid" means "acrylic acid and/or methacrylic acid".

<Photosensitive Composition>
The present invention is a photosensitive composition comprising (A) a polyfunctional (meth)acrylate of a lactone-modified polyhydric aliphatic alcohol, (B) an alicyclic monofunctional (meth)acrylate, and (C) an acylphosphine oxide-based photopolymerization initiator, wherein the content of the polyfunctional (meth)acrylate of the lactone-modified polyhydric aliphatic alcohol is 50 mass% or more in 100 mass% of the photosensitive composition.

The photosensitive composition of the present invention, having the above-mentioned structure, can provide a cured product having excellent elastic recovery, hardness, and adhesion. It is not certain why the photosensitive composition of the present invention can provide a cured product having excellent elastic recovery, hardness, and adhesion, but it is believed to be due to the following reasons. That is, by including a polyfunctional (meth)acrylate having a lactone-modified polyhydric aliphatic alcohol structure, 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 an alicyclic monofunctional (meth)acrylate, the glass transition temperature is increased and the hardness of the cured product can be increased. In addition, since the ester portion is bulky, it is possible to prevent curing shrinkage and improve adhesion. 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), an alicyclic monofunctional (meth)acrylate (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.

The polyfunctional (meth)acrylate of the lactone-modified polyhydric aliphatic alcohol may be, for example, a compound obtained by reacting a raw material component containing a polyhydric aliphatic alcohol, a lactone compound, and (meth)acrylic acid.

Polyhydric aliphatic alcohols include, but are not limited to, trimethylolethane, ditrimethylolethane, trimethylolpropane, ditrimethylolpropane, pentaerythritol, dipentaerythritol, tripentaerythritol, glycerin, etc.

The lactone compound is not particularly limited, but examples 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 (meth)acrylate with two or more functionalities, but a meth)acrylate with six or more functionalities is preferred because it can suppress the tack (adhesiveness) of the cured product and further improve adhesion.

The polyfunctional (meth)acrylate of the lactone-modified polyhydric aliphatic alcohol is preferably a compound represented by the following general formula (1).

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 above-mentioned chain-like saturated hydrocarbon group includes linear or branched saturated aliphatic hydrocarbon groups. Specific examples of monovalent saturated aliphatic hydrocarbon groups 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-like unsaturated hydrocarbon group may be a linear or branched unsaturated aliphatic hydrocarbon group. Specific examples of monovalent unsaturated aliphatic hydrocarbon groups 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 above-mentioned cyclic saturated hydrocarbon group includes an alicyclic hydrocarbon group. Specific examples of monovalent alicyclic hydrocarbon groups include monocyclic hydrocarbon groups such as cycloalkyl groups, such as a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, a cyclooctyl group, a cyclododecyl group, a cycloheptyl group, a cyclobutenyl group, a cyclopentenyl group, and a cyclohexenyl group; and polycyclic hydrocarbon groups, such as a dicyclopentanyl group, a dicyclopentenyl group, a tricyclodecanyl group, an adamantyl group, and an isobornyl group.

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, alkyl groups and alicyclic hydrocarbon groups are preferred because they are highly crosslinked, and alkyl groups are 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, and arylene groups. Of 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.

(In the formula, ^R6 represents a hydrogen atom, a substituent, or a hydrocarbon group which may have a substituent.)
Examples of the substituent represented by ^R6 include a hydroxyl group, a carboxyl group, an alkoxyl group, an alkyl group, a halogen atom, etc. Examples of the hydrocarbon group represented by ^R6 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 from 0 to 6, and more preferably an integer from 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.

More preferably, the polyfunctional (meth)acrylate of the lactone-modified polyhydric aliphatic alcohol is a compound represented by the following general formula (3):

(In formula (3), Y represents a structure represented by general formula (4). In formula (4), ^R7 represents a hydrogen atom or a methyl group. ^R8 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 can also be used. Examples of commercially available products of the 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 above lactone-modified polyhydric aliphatic alcohol, or may contain two or more types.

The content of the polyfunctional (meth)acrylate in the lactone-modified polyhydric aliphatic alcohol is 50% by mass or more in 100% by mass of the photosensitive composition. The content of the polyfunctional (meth)acrylate in the lactone-modified polyhydric aliphatic alcohol is 50% by mass or more, and further contains an alicyclic monofunctional (meth)acrylate and an acylphosphine oxide-based photopolymerization initiator described later, so that the photosensitive composition of the present invention can provide a cured product excellent in elastic recovery, hardness, and adhesion. The content of the polyfunctional (meth)acrylate in the lactone-modified polyhydric aliphatic alcohol is preferably 55% by mass or more, more preferably 60% by mass or more in 100% by mass of the photosensitive composition in terms of high elasticity. It is also preferably 97% by mass or less, more preferably 95% by mass or less, and even more preferably 90% by mass or less.

(B) 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 replaced 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 replaced 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 the cure shrinkage of the photosensitive composition and further improve adhesion. In addition, 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 the value 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, Photocuring Technology Data Book (Techno Net Books Co., Ltd.), etc.

Specific examples of the alicyclic monofunctional (meth)acrylates 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, tricyclodecanyl (meth)acrylate, and the like.

Among these, 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.

The content of the alicyclic monofunctional (meth)acrylate is preferably 49.9% 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. In terms of high elasticity and high adhesion, the content of the alicyclic monofunctional (meth)acrylate is more preferably 45% by mass or less in 100% by mass of the photosensitive composition, even more preferably 40% by mass or less, particularly preferably 37% by mass or less, and most preferably 35% by mass or less. The lower limit of the content of the alicyclic monofunctional (meth)acrylate is not particularly limited, but 2% by mass or more is preferable.

In the photosensitive composition of the present invention, the mass ratio (A/B) of the polyfunctional (meth)acrylate (A) of the lactone-modified polyhydric aliphatic alcohol to the alicyclic monofunctional (meth)acrylate (B) is preferably 1/1 to 10/1. When the mass ratio is within the above range, it is possible to achieve both high elasticity and high adhesion. In terms of achieving both higher elasticity and high adhesion, the mass ratio (A/B) is more preferably 1.5/1 or more, even more preferably 2/1 or more, and even more preferably 9/1 or less.

(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 has good curability and can give a cured product excellent in elastic recovery, hardness, and adhesion.

The above-mentioned acylphosphine oxide-based photopolymerization initiators include, for example, monoacylphosphine oxide-based 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, 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-based photopolymerization initiators.

Among them, the above-mentioned acylphosphine oxide photopolymerization initiators are highly active, and therefore, 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, Tylphosphine oxide is preferred, 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 are more preferred, and 2,4,6-trimethylbenzoyl-diphenylphosphine oxide and bis-(2,4,6-trimethylbenzoyl)phenylphosphine oxide are even more preferred.

The photosensitive composition may contain only one type of the acylphosphine oxide photopolymerization initiator, or may contain two or more types.

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 give a cured product having even better elastic recovery, hardness, and adhesion. 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, 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.

The content of the polymerization inhibitor is preferably 0.01 to 2% by mass in 100% by mass of the photosensitive composition. From the viewpoint 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) Other Components The photosensitive composition of the present invention may contain other components as necessary in addition to the above-mentioned components. Examples of the other components include polymerizable compounds other than the above-mentioned (meth)acrylates; resins; solvents; colorants; dispersants; heat resistance improvers; leveling agents; development aids; inorganic fine particles such as silica fine particles; coupling agents such as silane-based, aluminum-based, and titanium-based; fillers; curing aids; plasticizers; ultraviolet absorbers; antioxidants; matting agents; defoaming agents; antistatic agents; slip agents; surface modifiers; thixotropic agents; thixotropic aids; acid generators; photosensitizers; photoradical polymerization accelerators; surfactants; 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 each component used can also be appropriately set.

The photosensitive composition of the present invention may contain a solvent, but is preferably substantially free of solvent, since there is a risk that the alicyclic monofunctional (meth)acrylate 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 above-mentioned 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. For example, ethers such as tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, and diethylene glycol dimethyl ether; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; esters such as ethyl acetate, butyl acetate, propylene glycol monomethyl ether acetate, and 3-methoxybutyl acetate; alcohols such as methanol, ethanol, isopropanol, n-butanol, ethylene glycol monomethyl ether, and propylene glycol monomethyl ether; aromatic hydrocarbons such as toluene, xylene, and ethylbenzene; various organic solvents such as chloroform; dimethyl sulfoxide; and water. The above-mentioned 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 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 above-mentioned active energy rays can be electron beams, ultraviolet rays, or visible light. As light sources, thermionic emission guns, field emission guns, high-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halide lamps, gallium lamps, xenon lamps, carbon arc lamps, LEDs, etc. can be used.

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 even 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, the film thickness is preferably 5 μm or more. When the film thickness is 5 μm or more, it is possible to exhibit even better elastic recovery, hardness, and adhesion. 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 set appropriately depending on the purpose and use of the cured film, but for example, it is preferably 1000 μm or less, and 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 conforming to 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 higher, more preferably a rating of 4 or higher, and even more preferably a rating of 5 or higher, in an adhesion test by the cross-cut method determined according to a method conforming to JIS-K5600-5-6 (1999). Specifically, the adhesion test by the cross-cut method can be 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, and adhesion. 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 suitably used, for example, in hard coats, overcoats, optical films, insulating films, adhesives, sealants, etc.

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Note that "parts" refers to "parts by mass" unless otherwise specified.

In this example, each evaluation was performed using 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 remaining film ratio was evaluated as "5" when it was 100 to 98%, "4" when it was 98 to 95%, "3" when it was 95 to 92%, "2" when it was 92 to 90%, and "1" when it was less than 90%. The evaluation results are shown in Table 1.

(2) Pencil Hardness: The photosensitive composition was applied onto a 10 cm square glass substrate by a spin coater. The applied film was irradiated with ultraviolet light at an intensity of 1 J/ ^cm2 (converted to 365 nm illuminance) by 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 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

Examples 1 to 7, Comparative Examples 1 to 9
Photosensitive compositions were prepared by mixing various polyfunctional (meth)acrylates, monofunctional (meth)acrylates, 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.
(Polyfunctional Monomer)
DPCA-60: KAYARAD DPCA-60, manufactured by Nippon Kayaku Co., Ltd., polyacrylate of lactone-modified polyhydric aliphatic alcohol (6 mol of lactone added)
DPCA-120: KAYARAD DPCA-120, manufactured by Nippon Kayaku Co., Ltd., polyacrylate of lactone-modified polyhydric aliphatic alcohol (12 mol of lactone added)
DPHA: dipentaerythritol hexaacrylate DCPA: dimethylol-tricyclodecane diacrylate A-9300: manufactured by Shin-Nakamura Chemical Co., Ltd., ethoxylated isocyanuric acid triacrylate UX-5000: manufactured by Nippon Kayaku Co., Ltd., hexafunctional urethane acrylate

(Monofunctional Monomer)
CHMA: cyclohexyl methacrylate IBXA: isobornyl acrylate 511AS: FA-511AS, manufactured by Hitachi Chemical Co., Ltd., dicyclopentenyl acrylate 513M: FA-513M, manufactured by Hitachi Chemical Co., Ltd., dicyclopentanyl methacrylate MMA: methyl methacrylate 2EHA: 2-ethylhexyl acrylate

(Photopolymerization initiator)
Irg819: IRGACURE 819, manufactured by BASF, acylphosphine oxide type, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide TPO: IRGACURE TPO, manufactured by BASF, acylphosphine oxide type, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide Irg907: IRGACURE 907, manufactured by BASF, α-aminoalkylphenone type, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one OXE02: IRGACURE OXE02, manufactured by BASF, N-oxime ester type, ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(0-acetyloxime)

(Polymerization inhibitor)
W400: Antage W400, manufactured by Kawaguchi Chemical Industry Co., Ltd., 2,2'-methylenebis(4-methyl-6-t-butylphenol)
TEMPO: 4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxyl

From Table 1, it was found that the photosensitive composition of the example, which contains a polyfunctional (meth)acrylate of a lactone-modified polyhydric aliphatic alcohol, an alicyclic monofunctional (meth)acrylate, and an acylphosphine oxide-based photopolymerization initiator, and in which the content of the polyfunctional (meth)acrylate is 50% by mass or more based on 100% by mass of the photosensitive composition, gives a cured product that is excellent in elastic recovery, hardness, and adhesion.

Claims (12)

A photosensitive composition comprising (A) a polyfunctional (meth)acrylate of a lactone-modified polyhydric aliphatic alcohol, (B) an alicyclic monofunctional (meth)acrylate, and (C) an acylphosphine oxide-based photopolymerization initiator,
The polyfunctional (meth)acrylate (A) of a lactone-modified polyhydric aliphatic alcohol is a compound represented by the following general formula (1):
the content of the polyfunctional (meth)acrylate (A) of the lactone-modified polyhydric aliphatic alcohol is 55% by mass or more based on 100% by mass of the photosensitive composition;
The alicyclic monofunctional (meth)acrylate (B) has an alicyclic hydrocarbon group having 6 to 20 carbon atoms,
The acylphosphine oxide photopolymerization initiator (C) includes 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, or (2,5,6-trimethylbenzoyl)-2,4,4-trimethylpentylphosphine oxide,
The photosensitive composition is characterized in that it is used for hard coating.

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. A photosensitive composition comprising (A) a polyfunctional (meth)acrylate of a lactone-modified polyhydric aliphatic alcohol, (B) an alicyclic monofunctional (meth)acrylate, and (C) an acylphosphine oxide-based photopolymerization initiator,
The polyfunctional (meth)acrylate (A) of a lactone-modified polyhydric aliphatic alcohol is a compound represented by the following general formula (1):
the content of the polyfunctional (meth)acrylate (A) of the lactone-modified polyhydric aliphatic alcohol is 55% by mass or more based on 100% by mass of the photosensitive composition;
The alicyclic monofunctional (meth)acrylate (B) has an alicyclic hydrocarbon group having 6 to 20 carbon atoms,
The acylphosphine oxide photopolymerization initiator (C) includes 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, or (2,5,6-trimethylbenzoyl)-2,4,4-trimethylpentylphosphine oxide,
The photosensitive composition is used as an overcoat.

(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 a+b1+c≧6 is satisfied. l is an integer of 0 to 6.
In formula (2), R ⁴ represents a hydrogen atom or a methyl group. ⁵ represents a hydrocarbon group having 1 to 8 carbon atoms; and m represents an integer of 1 to 3. A photosensitive composition comprising (A) a polyfunctional (meth)acrylate of a lactone-modified polyhydric aliphatic alcohol, (B) an alicyclic monofunctional (meth)acrylate, and (C) an acylphosphine oxide-based photopolymerization initiator,
The polyfunctional (meth)acrylate (A) of a lactone-modified polyhydric aliphatic alcohol is a compound represented by the following general formula (1):
the content of the polyfunctional (meth)acrylate (A) of the lactone-modified polyhydric aliphatic alcohol is 55% by mass or more based on 100% by mass of the photosensitive composition;
The alicyclic monofunctional (meth)acrylate (B) has an alicyclic hydrocarbon group having 6 to 20 carbon atoms,
The acylphosphine oxide photopolymerization initiator (C) includes 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, or (2,5,6-trimethylbenzoyl)-2,4,4-trimethylpentylphosphine oxide,
The photosensitive composition is characterized in that it is used for an optical film.

(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 a+b1+c≧6 is satisfied. l is an integer of 0 to 6.
In formula (2), R ⁴ represents a hydrogen atom or a methyl group. ⁵ represents a hydrocarbon group having 1 to 8 carbon atoms; and m represents an integer of 1 to 3. A photosensitive composition comprising (A) a polyfunctional (meth)acrylate of a lactone-modified polyhydric aliphatic alcohol, (B) an alicyclic monofunctional (meth)acrylate, and (C) an acylphosphine oxide-based photopolymerization initiator,
The polyfunctional (meth)acrylate (A) of a lactone-modified polyhydric aliphatic alcohol is a compound represented by the following general formula (1):
the content of the polyfunctional (meth)acrylate (A) of the lactone-modified polyhydric aliphatic alcohol is 55% by mass or more based on 100% by mass of the photosensitive composition;
The alicyclic monofunctional (meth)acrylate (B) has an alicyclic hydrocarbon group having 6 to 20 carbon atoms,
The acylphosphine oxide photopolymerization initiator (C) includes 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, or (2,5,6-trimethylbenzoyl)-2,4,4-trimethylpentylphosphine oxide,
The photosensitive composition is characterized in that it is used for forming an insulating film.

(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 a+b1+c≧6 is satisfied. l is an integer of 0 to 6.
In formula (2), R ⁴ represents a hydrogen atom or a methyl group. ⁵ represents a hydrocarbon group having 1 to 8 carbon atoms; and m represents an integer of 1 to 3. A photosensitive composition comprising (A) a polyfunctional (meth)acrylate of a lactone-modified polyhydric aliphatic alcohol, (B) an alicyclic monofunctional (meth)acrylate, and (C) an acylphosphine oxide-based photopolymerization initiator,
The polyfunctional (meth)acrylate (A) of a lactone-modified polyhydric aliphatic alcohol is a compound represented by the following general formula (1):
the content of the polyfunctional (meth)acrylate (A) of the lactone-modified polyhydric aliphatic alcohol is 55% by mass or more based on 100% by mass of the photosensitive composition;
The alicyclic monofunctional (meth)acrylate (B) has an alicyclic hydrocarbon group having 6 to 20 carbon atoms,
The acylphosphine oxide photopolymerization initiator (C) includes 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, or (2,5,6-trimethylbenzoyl)-2,4,4-trimethylpentylphosphine oxide,
The photosensitive composition is used as an adhesive.

(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 a+b1+c≧6 is satisfied. l is an integer of 0 to 6.
In formula (2), R ⁴ represents a hydrogen atom or a methyl group. ⁵ represents a hydrocarbon group having 1 to 8 carbon atoms; and m represents an integer of 1 to 3. A photosensitive composition comprising (A) a polyfunctional (meth)acrylate of a lactone-modified polyhydric aliphatic alcohol, (B) an alicyclic monofunctional (meth)acrylate, and (C) an acylphosphine oxide-based photopolymerization initiator,
The polyfunctional (meth)acrylate (A) of a lactone-modified polyhydric aliphatic alcohol is a compound represented by the following general formula (1):
the content of the polyfunctional (meth)acrylate (A) of the lactone-modified polyhydric aliphatic alcohol is 55% by mass or more based on 100% by mass of the photosensitive composition;
The alicyclic monofunctional (meth)acrylate (B) has an alicyclic hydrocarbon group having 6 to 20 carbon atoms,
The acylphosphine oxide photopolymerization initiator (C) includes 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, or (2,5,6-trimethylbenzoyl)-2,4,4-trimethylpentylphosphine oxide,
The photosensitive composition is used as a sealant.

(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 a+b1+c≧6 is satisfied. l is an integer of 0 to 6.
In formula (2), R ⁴ represents a hydrogen atom or a methyl group. ⁵ represents a hydrocarbon group having 1 to 8 carbon atoms; and m represents an integer of 1 to 3. The photosensitive composition according to any one of claims 1 to 6, wherein a mass ratio (A/B) of the polyfunctional (meth)acrylate of the lactone-modified polyhydric aliphatic alcohol (A) to the alicyclic monofunctional (meth)acrylate (B) is 1.5/1 to 10/1. 8. The photosensitive composition according to claim 1, wherein the content of the alicyclic monofunctional (meth)acrylate (B) is 40% by mass or less in 100% by mass of the photosensitive composition. The photosensitive composition according to any one of claims 1 to 8 , wherein the content of the acylphosphine oxide-based photopolymerization initiator (C) is 0.1 to 2 mass% based on 100 mass% of the photosensitive composition. The photosensitive composition according to any one of claims 1 to 9 , further comprising a polymerization inhibitor (D). 11. The photosensitive composition according to claim 1, wherein the content of the solvent in the photosensitive composition is 3% by mass or less based on 100% by mass of the photosensitive composition. 12. The photosensitive composition according to claim 1, 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.