Photosensitive composition

Abstract

To provide a photosensitive composition that can give a cured product having excellent elastic recovery, hardness, adhesion, and durability.SOLUTION: A photosensitive composition contains a polyfunctional methacrylate of lactone-modified polyvalent aliphatic alcohol (A), a cyclization-polymerizable monomer (B), and an acyl phosphine oxide-based photopolymerization initiator (C). Preferably the photosensitive composition further contains a polymerization inhibitor (D). Preferably, the mass ratio between the polyfunctional methacrylate of lactone-modified polyvalent aliphatic alcohol (A) and the cyclization-polymerizable monomer (B) (A / B) is 1 / 1-10 / 1.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a photosensitive composition, and more particularly to a photosensitive composition that can give a cured product having excellent elastic recovery, adhesion, hardness and durability. [Background technology]

[0002] Photosensitive compositions that can react and harden when irradiated with light are being considered for use in a variety of applications, including color filters, photoresists, inks, hard coats, optical films, and other optical components used in liquid crystal display devices, as well as in electric and electronic devices. Resin compositions are being developed according to the performance required for each application. In recent years, optical components and electrical and electronic devices have become smaller, thinner, and more energy-efficient, and as a result, higher quality performance is required for the various components used in these devices. In order to meet such demands, research is being conducted on photosensitive compositions that can be used as materials for various components. 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 in 100 mass % of a radical polymerizable compound, as a composition that can form a cured coating film having excellent reactivity to active energy rays and 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. Patent Document 3 describes an active energy ray curable composition that has excellent mold releasability from a mold after curing and excellent water resistance, and 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 4 describes a photocurable composition that contains a specific cyclopolymerizable monomer, a polyfunctional radical polymerizable compound, and a photoradical polymerization initiator.

[0003] Although the above-mentioned prior art documents exhibit the performance required for various applications, each performance is not sufficient, and there is room for improvement, particularly in the durability of the cured product. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5283485 [Patent Document 2] Patent No. 6370748 [Patent Document 3] JP 2019-94484 A [Patent Document 4] Patent No. 5475173 Summary of the Invention [Problem to be solved by the invention]

[0005] 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. [Means for solving the problem]

[0006] As a result of intensive research, the present inventors have found that a specific photosensitive composition can provide a cured product having excellent elastic recovery, hardness, adhesion, and durability, and have completed the present invention. <1> ~ <9> This is achieved by: <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 polyfunctional (meth)acrylate (A) of the lactone-modified polyhydric aliphatic alcohol is a compound represented by the following general formula (1): <1> The photosensitive composition according to claim 1.

[0007] [ka] (In formula (1), R 1 , R 2 and R 3are 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+b+c≧6 is satisfied. l is an integer of 0 to 6. In formula (2), R 4 R represents a hydrogen atom or a methyl group. 5 represents a hydrocarbon group having 1 to 8 carbon atoms. m represents an integer of 1 to 3. <3> The cyclopolymerizable monomer (B) is a compound represented by the following general formula (3): <1> or <2> The photosensitive composition according to claim 1.

[0008] [ka] (In the formula, R 6 is a hydrogen atom or a methyl group, R 7 represents a hydrogen atom or a monovalent organic group. <4> The 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. <1> ~ <3> 13. The photosensitive composition according to claim 12, <5> The content of the cyclopolymerizable monomer (B) is 60% by mass or less in 100% by mass of the photosensitive composition. <1> ~ <4> 13. The photosensitive composition according to claim 12, <6> The content of the acylphosphine oxide-based photopolymerization initiator (C) is 0.1 to 2% by mass in 100% by mass of the photosensitive composition. <1> ~ <5> 13. The photosensitive composition according to claim 12, <7> The photosensitive composition further comprises a polymerization inhibitor (D). <1> ~ <6> 13. The photosensitive composition according to claim 12, <8> The photosensitive composition is characterized in that the content of the solvent is 3% by mass or less based on 100% by mass of the photosensitive composition. <1> ~ <7> 13. The photosensitive composition according to claim 12, <9> The photosensitive composition is characterized in that the content of the colorant is 3% by mass or less based on 100% by mass of the photosensitive composition. <1> ~ <8> 13. The photosensitive composition according to claim 12, Effect of the Invention

[0009] 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 is 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. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] 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 equal to or greater than the minimum value Min and equal to or less than the maximum value Max. Furthermore, when suitable numerical values ​​are described stepwise for the upper and lower limit values, suitable numerical ranges can be set by appropriately combining the upper and lower limit values ​​described separately.

[0011] <Photosensitive composition> The present invention is a photosensitive composition containing (A) a polyfunctional (meth)acrylate of a lactone-modified polyhydric aliphatic alcohol, (B) a cyclopolymerizable monomer, and (C) an acylphosphine oxide-based photopolymerization initiator. The photosensitive composition of the present invention has the above-mentioned constitution, and therefore 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, it is possible to perform curing sufficiently. The photosensitive composition of the present invention contains (A) a polyfunctional (meth)acrylate of a lactone-modified polyhydric aliphatic alcohol, (B) a cyclopolymerizable monomer, and (C) an acylphosphine oxide-based photopolymerization initiator. 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 difunctional or higher (meth)acrylate, but is preferably a hexafunctional or higher (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.

[0012] [ka] (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+b+c≧6 is satisfied. l is an integer of 0 to 6. In formula (2), R 4 R represents a hydrogen atom or a methyl group. 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 may be the same or different and represent 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-, -SO2- together with the hydrocarbon group. The above hydrocarbon group preferably has 1-20 carbon atoms, more preferably 2-15 carbon atoms, and even more preferably 3-10 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 may be a straight-chain or branched unsaturated aliphatic hydrocarbon group. 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.

[0013] 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 the group containing a bond such as -O-, -S-, -SO-, -SO2-, etc. together with the above-mentioned hydrocarbon group include -OR-, -RO-, -(RO) p Examples include -R- (p is an integer of 1 to 10), -SR-, -SRS-, -SO-R-, -R-SO-R-, -SO2-R-, -R-SO2-R- (R in each case represents the above-mentioned hydrocarbon group), etc. Among 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 the above general formula (1), [(XO) a -R 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. R 1The organic group represented by the formula (I) is preferably a chain-like saturated hydrocarbon group or a group which contains, together with the above-mentioned saturated hydrocarbon group, an -O-, -S-, -SO-, or -SO2- bond, and more preferably a chain-like saturated hydrocarbon group or a group which contains, together with the above-mentioned saturated hydrocarbon group, an -O- or -S- bond. R 1 The number of carbon atoms in the organic group represented by the following formula 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), -[R 3 -(OX) c ], 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. R 3 The organic group represented by the formula (I) is preferably a chain-like saturated hydrocarbon group or a group which contains, together with the above-mentioned saturated hydrocarbon group, an -O-, -S-, -SO-, or -SO2- bond, and more preferably a chain-like saturated hydrocarbon group or a group which contains, together with the above-mentioned saturated hydrocarbon group, an -O- or -S- bond. R 3 The number of carbon atoms in the organic group represented by the following formula 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), R 2 Examples of such structures include the following:

[0014] [ka] (In the formula, R 8 represents a hydrogen atom, a substituent, or a hydrocarbon group which may have a substituent. Above R 8 Examples of the substituent represented by R include a hydroxyl group, a carboxyl group, an alkoxyl group, an alkyl group, and a halogen atom. 8Examples of the hydrocarbon group represented by the formula (I) 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 0-6, and more preferably an integer of 0-3. 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+b l+c≧6 is satisfied. a and c are the same or different and each is more preferably an integer of 1 to 3. b is more preferably 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), R 4 represents a hydrogen atom or a methyl group. R 5 represents a hydrocarbon group having 1 to 8 carbon atoms. R 5 The hydrocarbon group represented by the formula (I) 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. R 5 The hydrocarbon group represented by the following formula (1) 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.

[0015] [ka] (In formula (4), Y represents a structure represented by general formula (5). In formula (5), R 9 R represents a hydrogen atom or a methyl group. 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 can 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 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, based on 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 below, the photosensitive composition of the present invention can provide a cured product that is more excellent in 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, based on 100% by mass of the photosensitive composition, in terms of high elasticity. 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.

[0016] (B) Cyclopolymerizable monomer The cyclic polymerizable 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 suitable. Examples of the acrylic ether dimer include compounds described in JP 2018-154720 A (paragraph number 0027). Examples of the 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 preferable. 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 (A) of the lactone-modified polyhydric aliphatic alcohol to the cyclopolymerizable monomer (B) is preferably 1 / 1 to 10 / 1. When the mass ratio is within the above range, both high elasticity and high adhesion can be achieved. In terms of achieving 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.

[0017] [ka] (In the formula, R 6 is a hydrogen atom or a methyl group, R 7 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 (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 that occurs in the cyclopolymerization:

[0018] [ka] (In the formula, R 11 is a hydrogen atom or a methyl group, 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), which facilitates interaction between the tetrahydrofuran ring and the functional group on the substrate surface, and is therefore believed to exhibit good adhesion. The methylene groups on both sides of the tetrahydrofuran ring are believed to improve the flexibility of the polymer chain, which makes the above-mentioned interaction more effective. Furthermore, the cured product of the α-allyloxymethylacrylic acid monomer also has excellent heat resistance, compatibility, and mechanical properties, and the reason why these various properties are exhibited is believed to be due to the structure represented by the formula (6).

[0019] The α-allyloxymethylacrylic acid monomer preferably has a boiling point of 95°C or more 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 more. It has been confirmed that there is a strong correlation between boiling point and curability in the α-allyloxymethylacrylic acid monomer, and if the boiling point is 95°C or more under 1333 Pa conditions, the monomer will exhibit excellent curability. In addition, by having such a boiling point, the α-allyloxymethylacrylic acid monomer will have excellent curing speed, surface curability, and thin film curability. 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., it may be cured depending on the conditions, but in order to obtain good curability, the boiling point at normal pressure is preferably 205° C. or higher. It is more preferably 210° C. or higher, and most preferably 215° C. or higher.

[0020] R in the above formula (3) 7 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 chain saturated hydrocarbon groups having 1 to 30 carbon atoms, chain 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 chain saturated hydrocarbon groups having 1 to 10 carbon atoms, chain 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 above-mentioned 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.

[0021] The chain saturated hydrocarbon group may be a straight-chain or branched hydrocarbon group without any particular limitation, 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. Suitable 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 a hydrocarbon group containing an aromatic ring structure having six or more members. The alkyl group may be any group, and is not particularly limited. Suitable examples include phenyl, methylphenyl, dimethylphenyl, trimethylphenyl, 4-t-butylphenyl, benzyl, diphenylmethyl, diphenylethyl, triphenylmethyl, cinnamyl, naphthyl, anthranyl and the like. 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 having a hydrocarbon skeleton containing an ether bond include chain ether groups such as methoxyethyl, methoxyethoxyethyl, methoxyethoxyethoxyethyl, 3-methoxybutyl, ethoxyethyl, and ethoxyethoxyethyl; cyclopentoxyethyl, cyclohexyloxyethyl, cyclopentoxyethoxyethyl, cyclohexyloxyethoxyethyl, and the like. 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.

[0022] 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, α-Allyloxymethylacrylic acid n-hexyl, α-allyloxymethylacrylic acid s-hexyl, α-allyloxymethylacrylic acid n-heptyl, α-allyloxymethylacrylic acid n-octyl, α-allyloxymethylacrylic acid s-octyl, α-allyloxymethylacrylic acid t-octyl, α-allyloxymethylacrylic acid 2-ethylhexyl, α-allyloxymethylacrylic acid capryl, α-allyloxymethylacrylic acid nonyl, α-allyloxymethylacrylic acid decyl, α-allyloxymethylacrylic acid undecyl , lauryl α-allyloxymethylacrylate, tridecyl α-allyloxymethylacrylate, myristyl α-allyloxymethylacrylate, pentadecyl α-allyloxymethylacrylate, cetyl α-allyloxymethylacrylate, heptadecyl α-allyloxymethylacrylate, stearyl α-allyloxymethylacrylate, nonadecyl α-allyloxymethylacrylate, eicosyl α-allyloxymethylacrylate, ceryl α-allyloxymethylacrylate, melissyl α-allyloxymethylacrylate, ... crotyl dimethylacrylate, 1,1-dimethyl-2-propenyl α-allyloxymethylacrylate, 2-methylbutenyl α-allyloxymethylacrylate, 3-methyl-2-butenyl α-allyloxymethylacrylate, 3-methyl-3-butenyl α-allyloxymethylacrylate, 2-methyl-3-butenyl α-allyloxymethylacrylate, oleyl α-allyloxymethylacrylate, linoleyl α-allyloxymethylacrylate, linolene α-allyloxymethylacrylate, cyclopentyl α-allyloxymethylacrylate,α-Allyloxymethylacrylic acid cyclopentyl methyl, α-Allyloxymethylacrylic acid cyclohexyl, α-Allyloxymethylacrylic acid cyclohexyl methyl, α-Allyloxymethylacrylic acid 4-methylcyclohexyl, α-Allyloxymethylacrylic acid 4-t-butylcyclohexyl, α-Allyloxymethylacrylic acid tricyclodecanyl, α-Allyloxymethylacrylic acid isobornyl, α-Allyloxymethylacrylic acid adamantyl, α-Allyloxymethylacrylic acid dicyclopentanyl, α-Allyloxymethylacrylic acid dicyclopentenyl acrylate, phenyl α-allyloxymethylacrylate, methylphenyl α-allyloxymethylacrylate, dimethylphenyl α-allyloxymethylacrylate, trimethylphenyl α-allyloxymethylacrylate, 4-t-butylphenyl α-allyloxymethylacrylate, benzyl α-allyloxymethylacrylate, diphenylmethyl α-allyloxymethylacrylate, diphenylethyl α-allyloxymethylacrylate, triphenylmethyl α-allyloxymethylacrylate, α-allyloxymethylacrylic α-Allyloxymethylacrylic acid cinnamyl, α-allyloxymethylacrylic acid naphthyl, α-allyloxymethylacrylic acid anthranyl, α-allyloxymethylacrylic acid methoxyethyl, α-allyloxymethylacrylic acid methoxyethoxyethyl, α-allyloxymethylacrylic acid methoxyethoxyethoxyethyl, α-allyloxymethylacrylic acid 3-methoxybutyl, α-allyloxymethylacrylic acid ethoxyethyl, α-allyloxymethylacrylic acid ethoxyethoxyethyl, α-allyloxymethylacrylic acid cyclopentoxyethyl, α-allyloxy cyclohexyloxyethyl methylacrylate, cyclopentoxyethoxyethyl α-allyloxymethylacrylate, cyclohexyloxyethoxyethyl α-allyloxymethylacrylate, dicyclopentenyloxyethyl α-allyloxymethylacrylate, phenoxyethyl α-allyloxymethylacrylate, phenoxyethoxyethyl α-allyloxymethylacrylate, glycidyl α-allyloxymethylacrylate, β-methylglycidyl α-allyloxymethylacrylate, β-ethylglycidyl α-allyloxymethylacrylate,Preferred examples thereof include 3,4-epoxycyclohexylmethyl α-allyloxymethyl acrylate, 2-oxetanemethyl α-allyloxymethyl acrylate, 3-methyl-3-oxetanemethyl α-allyloxymethyl acrylate, 3-ethyl-3-oxetanemethyl α-allyloxymethyl acrylate, tetrahydrofuranyl α-allyloxymethyl acrylate, tetrahydrofurfuryl α-allyloxymethyl acrylate, tetrahydropyranyl α-allyloxymethyl acrylate, dioxazolanyl, and dioxanyl α-allyloxymethyl acrylate. 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 ... 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, R in the above formula (3) 7is 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.

[0023] As a method for producing an α-allyloxymethylacrylic acid monomer, the method described in Japanese Patent No. 5591543 (paragraphs 0037 to 0040) can be mentioned.

[0024] (C) Acylphosphine oxide photoinitiator The photosensitive composition of the present invention further contains an acylphosphine oxide-based 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, adhesion, and durability.

[0025] 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 them, the above-mentioned 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, 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.

[0026] (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) etc.), 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.

[0027] (E) Alicyclic monofunctional (meth)acrylate The 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 value described in POLYMER HANDBOOK (Polymer Handbook, 4th Edition, Wily 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, Inc.), etc. 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 above-mentioned 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.

[0028] (F) Other ingredients 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).

[0029] 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, the amount 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 above-mentioned solvent includes those that are usually used in photosensitive compositions, and may be appropriately selected according to the purpose and use, and is not particularly limited. For example, 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 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 thereof include known pigments and dyes that are commonly used as colorants.

[0030] (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 step 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, etc., but is, for example, 10 to 10,000 mJ / cm 2 is preferable, and 20 to 9000 mJ / cm 2 More preferably, 30 to 8000 mJ / cm 2 is more preferred. 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 depending on the purpose and use of the cured film, but is more preferably 1000 μm or less, and even more preferably 800 μm or less, for example. The cured product obtained by curing the photosensitive composition of the present invention preferably has an elastic recovery rate 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, more preferably 4H or more. The pencil hardness can be determined by a method in accordance with JIS-K5600-5-4 (1999), 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 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 conforming to 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.

[0031] (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. EXAMPLES

[0032] 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 then irradiated with 1 J / cm 2 using a UV aligner (TME-150RNS, manufactured by TOPCON) equipped with a 2.0 kW ultra-high pressure mercury lamp. 2 The coating was irradiated with ultraviolet light at an intensity of 100-95%, 20-85%, 30-65%, 40-65%, and 50-85%. The cured coating was then subjected to JIS K5600-5-6:1999 "General test methods for paints - Part 5: Mechanical properties of coatings - Section 6: Adhesion (cross-cut method)". The coating was rated as 1 if the remaining rate was 100-95%, 2 if it was 95-85%, 3 if it was 85-65%, 4 if it was 65-35%, and 5 if 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 then irradiated with 1 J / cm 2 using a UV aligner (TME-150RNS, manufactured by TOPCON) equipped with a 2.0 kW ultra-high pressure mercury lamp. 2 (365 nm illuminance equivalent) 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, the old JIS version of JIS-K5400 (1990), and the hardest pencil that did not produce a scratch was recorded as the hardness (surface hardness). (3) Elastic recovery The photosensitive composition was applied onto a 10 cm square glass substrate using a spin coater. The applied film was then irradiated with 1 J / cm 2 using a UV aligner (TME-150RNS, manufactured by TOPCON) equipped with a 2.0 kW ultra-high pressure mercury lamp. 2 The cured film was obtained by irradiating ultraviolet light at an intensity of 1000 nm (converted into 365 nm illuminance). 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 80 mN was applied and then unloaded to 0.49 mN using a 100 μm square flat indenter at a loading rate and unloading rate of 4.7 mN / sec. Load-deformation curves during loading and unloading were created. 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 according to the following formula. Elastic recovery rate (%) = (L1-L2) x 100 / L1

[0033] (4) Durability (reliability) 4-1. Preparation of samples for reliability evaluation The photosensitive composition was applied to a 10 cm square glass substrate using a spin coater, and the applied film was then irradiated with 1 J / cm 2 using a UV aligner (TME-150RNS, manufactured by TOPCON) equipped with a 2.0 kW ultra-high pressure mercury lamp. 2The film was developed by irradiating it with ultraviolet light at an intensity of 1000 nm (equivalent to 365 nm illuminance) and then heated in a 100°C oven (PHH-201, Espec Corp.) for 10 minutes. On this cured product, a titanium oxide 2-layer / silica 3-layer alternate deposition film (visible light anti-reflection film) was formed by ion-assisted electron beam deposition using a high-speed IAD vacuum thin film forming device (Shinchron Corp., 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 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 Corp.). 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 cycle test using a thermal shock device (TSA-71S, manufactured by Espec Corporation), 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 using a paint shaker according to the formulations shown in Table 1. The components shown in Table 1 are as follows. <Monofunctional monomer> AOMA: α-allyloxymethyl methyl acrylate EtAOMA: Ethyl α-allyloxymethylacrylate ChAOMA: α-allyloxymethyl hexyl acrylate 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 made by Nippon Kayaku DPHA: Kyoeisha Chemical, dipentaerythritol hexaacrylate A-9300: Shin-Nakamura Chemical Co., Ltd., ethoxylated isocyanuric acid triacrylate UX-5000: Nippon Kayaku Co., Ltd., 6-functional urethane acrylate <Photopolymerization initiator> All made by BASF Omn 184: Omnirad 184 (α-hydroxyalkylphenone) 1-Hydroxycyclohexyl phenyl ketone Omn TPO: Omnirad TPO H (Acylphosphine Oxide) 2,4,6-Trimethylbenzoyl-diphenylphosphine oxide Omn 819: Omnirad 819 (Acylphosphine Oxide) Bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide Omn 907: Omnirad 907 (α-aminoalkylphenone series) 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one Irg OXE02: Irgacure OXE02 (N-Oxime Ester Series) 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

[0034] [Table 1] From Table 1, it was found that the photosensitive compositions of the Examples, which contain a polyfunctional (meth)acrylate of a lactone-modified polyhydric aliphatic alcohol, a cyclopolymerizable monomer, and an acylphosphine oxide-based photopolymerization initiator, give cured products excellent in elastic recovery, hardness, adhesion, and durability (reliability). In particular, the photosensitive compositions of the Examples were confirmed to be significantly superior in adhesion (cross-cut) and reliability (THS, TC) compared to the Comparative Examples. In addition, when comparing the total performance of Examples 2 to 4, all of them are at a high level, but as in Example 4 (using α-allyloxymethyl hexyl acrylate), the R 7 This confirmed the advantage of using a cyclopolymerizable monomer with a moderately high hydrophobicity. [Industrial Applicability]

[0035] 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

1. 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. 【Chemistry 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. 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.

2. 2. The photosensitive composition according to claim 1, wherein the content of the acylphosphine oxide-based photopolymerization initiator (C) is 0.1 to 2% by mass based on 100% by mass of the photosensitive composition.

3. 3. The photosensitive composition according to claim 1, further comprising an alicyclic monofunctional (meth)acrylate (E).

4. 3. The photosensitive composition according to claim 1, wherein the cyclopolymerizable monomer (B) is a compound represented by the following general formula (3): 【Chemistry 2】 (In the formula, R ６ is a hydrogen atom or a methyl group, R ７ represents a hydrogen atom or a monovalent organic group.

5. 3. The photosensitive composition according to claim 1, wherein 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.

6. 4. The photosensitive composition according to claim 3, wherein the content of the alicyclic monofunctional (meth)acrylate (E) is from 2% by mass to 40% by mass in 100% by mass of the photosensitive composition.

7. 3. The photosensitive composition according to claim 1, further comprising a polymerization inhibitor (D).

8. 3. The photosensitive composition according to claim 1, wherein the photosensitive composition has a solvent content of 3% by mass or less relative to 100% by mass of the photosensitive composition.

9. 3. 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.

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