CN111201252A

CN111201252A - Resin and adhesive composition

Info

Publication number: CN111201252A
Application number: CN201880066262.4A
Authority: CN
Inventors: 浅津悠司; 小泽昭一; 国见信孝
Original assignee: Sumitomo Chemical Co Ltd
Current assignee: Sumitomo Chemical Co Ltd
Priority date: 2017-10-13
Filing date: 2018-10-03
Publication date: 2020-05-26
Also published as: TW201927988A; JP2019090005A; KR20200067832A; WO2019073869A1

Abstract

The pressure-sensitive adhesive composition contains a resin (A) having a structural unit having a merocyanine structure and having a glass transition temperature of 40 ℃ or lower, a pressure-sensitive adhesive composition containing the resin (A), and an optical laminate containing a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition containing the resin (A) and an optical film.

Description

Resin and adhesive composition

Technical Field

The present invention relates to a resin, a pressure-sensitive adhesive composition containing the resin, and an optical film in which a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition is laminated.

Background

Patent document 1 describes an adhesive composition containing: a copolymer of N-butyl acrylate, 2-hydroxyethyl acrylate and N, N-dimethylacrylamide, and an ultraviolet absorber (BONASORB UA-3901, manufactured by Oriental chemical industries, Ltd.) as an indole derivative.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2017-48340

Disclosure of Invention

Problems to be solved by the invention

However, when an optical laminate in which an adhesive layer formed from the adhesive composition described in patent document 1 and a polarizing plate are laminated is subjected to a durability test (for example, a heat resistance test at 85 ℃ for 120 hours), an ultraviolet absorber precipitates, and the bleeding resistance is insufficient.

Means for solving the problems

The present invention includes the following inventions.

[1] A resin (A) which contains a structural unit having a merocyanine structure and has a glass transition temperature of 40 ℃ or lower.

[2] The resin according to [1], wherein the resin (A) is a resin satisfying the following formula (1).

ε(405)≥0.02 (1)

[ in the formula (1),. epsilon. (. 405) represents the gram absorption coefficient of the resin at a wavelength of 405 nm. The unit of the gram absorption coefficient is L/(g.cm). ]

[3] The resin according to [1] or [2], wherein the resin (A) is a resin satisfying the following formula (2).

ε(405)/ε(440)≥5 (2)

[ in the formula (2),. epsilon. (. epsilon.) (405) represents the gram absorption coefficient of the resin at a wavelength of 405nm, and. epsilon. (. epsilon.) (440) represents the gram absorption coefficient of the resin at a wavelength of 440 nm. ]

[4] The resin according to any one of [1] to [3], wherein the resin (A) is a resin containing a structural unit having a merocyanine structure in a side chain.

[5] The resin according to [4], wherein the structural unit having a merocyanine structure in a side chain is a structural unit derived from a compound represented by formula (I).

[ in the formula, R¹、R²、R³、R⁴And R⁵Each independently represents a hydrogen atom, an optionally substituted aliphatic hydrocarbon group having 1 to 25 carbon atoms, an optionally substituted aromatic hydrocarbon group having 6 to 15 carbon atoms, a heterocyclic group or an ethylenically unsaturated group, -CH contained in the aliphatic hydrocarbon group or the aromatic hydrocarbon group₂-is optionally substituted by-NR^1A－、－SO₂-, -CO-, -O-or-S-.

R⁶And R⁷Each independently represents a hydrogen atom, an alkyl group having 1 to 25 carbon atoms, an electron-withdrawing group or an ethylenically unsaturated group.

R^1ARepresents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

R¹And R²Optionally joined to each other to form a ring structure, R²And R³Optionally joined to each other to form a ring structure, R²And R⁴Optionally joined to each other to form a ring structure, R³And R⁶Optionally joined to each other to form a ring structure, R⁵And R⁷Optionally joined to each other to form a ring structure, R⁶And R⁷Optionally interconnected to form a ring structure.

Wherein R is¹～R⁷Wherein 1 is an ethylenically unsaturated groupAnd (4) clustering.]

[6] The resin of claim 5, wherein the compound of formula (I) is a compound of formula (II).

[ in the formula (II), R¹¹、R¹²、R¹³、R¹⁴And R¹⁵Each independently represents a hydrogen atom, an optionally substituted aliphatic hydrocarbon group having 1 to 25 carbon atoms, an optionally substituted aromatic hydrocarbon group having 6 to 15 carbon atoms or a heterocyclic group, or-CH contained in the aliphatic hydrocarbon group or the aromatic hydrocarbon group₂-is optionally substituted by-NR^11A－、－SO₂-, -CO-, -O-or-S-.

R¹⁶And R¹⁷Each independently represents a hydrogen atom, an alkyl group having 1 to 25 carbon atoms, an electron-withdrawing group or an ethylenically unsaturated group.

R^11ARepresents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

R¹²And R¹³Optionally joined to each other to form a ring structure, R¹³And R¹⁴Optionally interconnected to form a ring structure.

Wherein R is¹⁶Or R¹⁷Any 1 of which is an ethylenically unsaturated group.]

[7] The resin according to any one of [1] to [6], wherein the resin (A) further comprises at least 1 structural unit selected from the structural units described in the following group A.

Group A: a structural unit derived from a (meth) acrylate, a structural unit derived from a styrenic monomer, a structural unit derived from a vinyl monomer, a structural unit represented by the formula (a), a structural unit represented by the formula (b), and a structural unit represented by the formula (c)

[ in the formula, R^a1Represents a divalent hydrocarbon group.

R^b1And R^b2Each independently represents a hydrogen atom or a hydrocarbon group.

R^c1And R^c2Each independently represents a divalent hydrocarbon group.]

[8] The resin according to [7], wherein the content of at least 1 structural unit selected from the structural units described in group A is 50% by mass or more based on the total structural units of the resin (A).

[9] An adhesive composition comprising the resin according to any one of [1] to [8 ].

[10] The adhesive composition according to [9], further comprising a crosslinking agent (B).

[11] An adhesive layer formed from the adhesive composition of [9] or [10 ].

[12] The adhesive layer according to [11], which satisfies the following formula (3).

A(405)≥0.5 (3)

In the formula (3), A (405) represents the absorbance at a wavelength of 405 nm. ]

[13] The adhesive layer according to [12], which further satisfies the following formula (4).

A(405)/A(440)≥5 (4)

In the formula (4), A (405) represents the absorbance at a wavelength of 405nm, and A (440) represents the absorbance at a wavelength of 440 nm. ]

[14] An optical laminate comprising an optical film laminated on at least one side of the pressure-sensitive adhesive layer according to any one of [11] to [13 ].

[15] The optical laminate according to [14], wherein the optical film is a polarizing plate.

[16] An image display device comprising the optical laminate according to [15 ].

[17] A compound represented by the formula (II).

[ in the formula (II), R¹¹、R¹²、R¹³、R¹⁴And R¹⁵Each independently represents a hydrogen atom, optionallyAn aliphatic hydrocarbon group having 1 to 25 carbon atoms and a substituent, an optionally substituted aromatic hydrocarbon group having 6 to 15 carbon atoms or a heterocyclic group, -CH contained in the aliphatic hydrocarbon group or the aromatic hydrocarbon group₂-is optionally substituted by-NR^11A－、－SO₂-, -CO-, -O-or-S-.

R^11ARepresents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

R¹²And R¹³Optionally joined to each other to form a ring structure, R¹²And R¹⁴Optionally interconnected to form a ring structure.

Effects of the invention

The optical laminate comprising a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition containing the resin of the present invention and an optical film laminated thereon has good bleed-out resistance even when subjected to a durability test (for example, a heat resistance test at 85 ℃ for 120 hours).

Drawings

Fig. 1 shows an example of the layer structure of the pressure-sensitive adhesive layer of the present invention.

Fig. 2 shows an example of the layer structure of the optical laminate of the present invention.

Fig. 3 shows an example of the layer structure of the optical laminate of the present invention.

Fig. 4 shows an example of the layer structure of the optical laminate of the present invention.

Fig. 5 shows an example of the layer structure of the optical laminate of the present invention.

Detailed Description

< resin (A) >

The resin (A) contains a structural unit having a merocyanine structure and has a glass transition temperature of 40 ℃ or lower.

In the present invention, the merocyanine structure refers to a partial structure represented by > N-C < C. The merocyanine structure of the present invention does not include an aromatic fused ring (e.g., a benzotriazole ring, a benzimidazole ring, an indole ring, an isoindole ring, a quinoline ring, etc.) having a partial structure represented by > N-C ═ C < as a ring component.

The resin (a) may have a merocyanine structure in the main chain or in the side chain. The resin (a) more preferably contains a structural unit having a merocyanine structure in a side chain. The structural unit having a merocyanine structure in a side chain is preferably a structural unit derived from a light selective absorbing compound having a merocyanine structure.

The glass transition temperature (Tg) of the resin (A) is 40 ℃ or lower, preferably 20 ℃ or lower, more preferably 10 ℃ or lower, and still more preferably 0 ℃ or lower. The glass transition temperature of the resin (A) is usually-80 ℃ or higher, preferably-60 ℃ or higher, more preferably-50 ℃ or higher, still more preferably-45 ℃ or higher, and particularly preferably-30 ℃ or higher. When the glass transition temperature of the resin (a) is 40 ℃ or lower, it is advantageous to improve the adhesion of the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition containing the resin (a) to an adherend. Further, when the glass transition temperature of the resin (A) is-80 ℃ or higher, it is advantageous to improve the durability of the pressure-sensitive adhesive layer formed of the pressure-sensitive adhesive composition containing the resin (A) (appearance defects in a high-temperature test: cohesive failure, etc.). The glass transition temperature can be measured by a Differential Scanning Calorimeter (DSC).

The structural unit having a merocyanine structure in a side chain is not particularly limited, and is preferably a structural unit derived from a compound having a polymerizable group and a merocyanine structure, and more preferably a structural unit derived from a light selective absorbing compound having a polymerizable group and a merocyanine structure.

The light selective absorbing compound having a polymerizable group and a merocyanine structure preferably satisfies the following formula (1-a), and more preferably also satisfies formula (2-a).

ε(405)≥5 (1－a)

[ in the formula (1-a), [ epsilon ] (405) represents the gram absorption coefficient of a compound having a polymerizable group and a merocyanine structure at a wavelength of 405 nm. The unit of the gram absorption coefficient is L/(g.cm). ]

ε(405)/ε(440)≥20 (2－a)

[ in the formula (2-a), [ epsilon ] (405) represents the gram absorption coefficient of the compound having a polymerizable group and a merocyanine structure at a wavelength of 405nm, and [ epsilon ] (440) represents the gram absorption coefficient of the compound having a polymerizable group and a merocyanine structure at a wavelength of 440 nm. ]

The value of ∈ (405) of the compound having a polymerizable group and a merocyanine structure is preferably 5L/(g · cm) or more, more preferably 10L/(g · cm) or more, still more preferably 20L/(g · cm) or more, still more preferably 30L/(g · cm) or more, and usually 500L/(g · cm) or less. The larger the value of ε (405), the more easily the compound absorbs light having a wavelength of 405nm, and the more easily the compound exhibits a function of suppressing deterioration due to ultraviolet rays or short-wavelength visible light.

The value of ∈ (405)/∈ (440) of the compound having a polymerizable group and a merocyanine structure is preferably 20 or more, more preferably 40 or more, still more preferably 70 or more, and particularly more preferably 80 or more. A resin containing a compound having a large value of ∈ (405)/∈ (440) can absorb light near 405nm without impairing color expression of a display device, and can suppress light degradation of a display device such as a retardation film or an organic EL element.

Examples of the structural unit having a merocyanine structure in a side chain include structural units derived from a compound represented by formula (I).

[ in the formula (I), R¹、R²、R³、R⁴And R⁵Each independently represents a hydrogen atom, an optionally substituted aliphatic hydrocarbon group having 1 to 25 carbon atoms, an optionally substituted aromatic hydrocarbon group having 6 to 15 carbon atoms, a heterocyclic group or an ethylenically unsaturated group, -CH contained in the aliphatic hydrocarbon group or the aromatic hydrocarbon group₂-is optionally substituted by-NR^1A－、－SO₂-, -CO-, -O-or-S-.

R^1AAnd R^1BEach independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

Wherein R is¹～R⁷Wherein 1 is an ethylenically unsaturated group]

As R¹～R⁵Examples of the aliphatic hydrocarbon group having 1 to 25 carbon atoms include: a straight-chain or branched alkyl group having 1 to 25 carbon atoms such as a methyl group, an ethyl group, a n-propyl group, an isopropyl group, a n-butyl group, a tert-butyl group, a sec-butyl group, a n-pentyl group, an isopentyl group, a n-hexyl group, an isohexyl group, a n-octyl group, an isooctyl group, a n-nonyl group, an isononyl group, a n-decyl group, an isodecyl group, a n-dodecyl group, an isododecyl group, an undecyl group, a lauryl group, a myri: cycloalkyl groups having 3 to 25 carbon atoms such as cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl; cycloalkyl alkyl group having 4 to 25 carbon atoms such as cyclohexylmethyl group, etc., preferably alkyl group having 4 to 25 carbon atoms.

As R¹～R⁵The optional substituent of the aliphatic hydrocarbon group having 1 to 25 carbon atoms includes: hydroxyl group, cyano group, halogen atom, mercapto group, amino group, nitro group, etc.

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

As R¹～R⁵The aromatic hydrocarbon group having 6 to 15 carbon atoms includes: aryl groups having 6 to 15 carbon atoms such as phenyl, naphthyl, anthryl and biphenyl groups; aralkyl groups having 7 to 15 carbon atoms such as benzyl, phenethyl, naphthylmethyl, and phenyl.

As R¹～R⁵The substituent optionally contained in the aromatic hydrocarbon group having 6 to 15 carbon atoms includes: hydroxy, cyano, halogen atom, mercapto, amino, nitro, alkoxy, alkylthio, alkoxycarbonyl, acyl, acyloxy, -C (NR)^2A)R^2B、－CONR^3AR^3B、－SO₂R^4A(R^2A、R^2B、R^3AAnd R^3BEach independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, R^4AAn alkyl group having 1 to 6 carbon atoms) and the like.

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

Examples of the alkoxy group include alkoxy groups having 1 to 12 carbon atoms such as a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group, a hexyloxy group, an octyloxy group, a 2-ethylhexyloxy group, a nonyloxy group, a decyloxy group, an undecyloxy group, and a dodecyloxy group.

The alkylthio group includes alkylthio groups having 1 to 12 carbon atoms such as a methylthio group, an ethylthio group, a propylthio group, and a butylthio group.

Examples of the acyl group include acyl groups having 2 to 13 carbon atoms such as an acetyl group, a propionyl group, and a butyryl group.

Examples of the acyloxy group include acyloxy groups having 2 to 13 carbon atoms such as a methylcarbonyloxy group, an ethylcarbonyloxy group, an n-propylcarbonyloxy group, an isopropylcarbonyloxy group, an n-butylcarbonyloxy group, a sec-butylcarbonyloxy group, a tert-butylcarbonyloxy group, a pentylcarbonyloxy group, a hexylcarbonyloxy group, an octylcarbonyloxy group and a 2-ethylhexylcarbonyloxy group.

Examples of the alkoxycarbonyl group include: alkoxycarbonyl group having 2 to 13 carbon atoms such as methoxycarbonyl group, ethoxycarbonyl group, propoxycarbonyl group, butoxycarbonyl group, pentyloxycarbonyl group, hexyloxycarbonyl group, octyloxycarbonyl group, 2-ethylhexyloxycarbonyl group, nonyloxycarbonyl group, decyloxycarbonyl group, undecyloxycarbonyl group, dodecyloxycarbonyl group and the like.

as-CONR^3AR^3BExamples thereof include aminocarbonyl group, methylaminocarbonyl group, dimethylaminocarbonyl group, ethylaminocarbonyl group, and methylmethylaminocarbonyl group.

as-C (NR)^2A)R^2BExamples thereof include methylimino, dimethylimino and methylethylimino.

as-SO₂R^4AExamples thereof include methylsulfonyl group and ethylsulfonyl group.

As R^1AExamples of the alkyl group having 1 to 6 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, sec-butyl and the like.

As R¹～R⁵Examples of the heterocyclic group include: and aliphatic heterocyclic groups having 4 to 20 carbon atoms such as pyrrolidine ring group, pyrroline ring group, imidazolidine ring group, imidazoline ring group, oxazoline ring group, thiazoline ring group, piperidine ring group, morpholine ring group, piperazine ring group, indole ring group, isoindole ring group, quinoline ring group, thiophene ring group, pyrrole ring group, thiazoline ring group, and furan ring group, and aromatic heterocyclic groups having 3 to 20 carbon atoms.

As R⁶And R⁷Examples of the alkyl group having 1 to 25 carbon atoms include: and linear or branched alkyl groups having 1 to 25 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, sec-butyl, n-pentyl, isopentyl, n-hexyl, isohexyl, n-octyl, isooctyl, n-nonyl, isononyl, n-decyl, isodecyl, n-dodecyl, isododecyl, undecyl, lauryl, myristyl, hexadecyl, and stearyl groups.

As R⁶And R⁷Examples of the electron-withdrawing group include: a cyano group, a nitro group, a halogen atom, an alkyl group substituted with a halogen atom, a group represented by the formula (I-1).

^*-X¹-R¹¹¹(I-1)

[ in the formula, R¹¹¹Represents a hydrogen atom or a hydrocarbon group having 1 to 25 carbon atoms, and at least 1 of methylene groups contained in the alkyl group is optionally replaced by an oxygen atom.

X¹represents-CO-¹、－COO－*¹、－CS－*¹、－CSS－*¹、－CSNR¹¹²－*¹、－CONR¹¹³－*¹、－CNR¹¹⁴－*¹or-SO₂－*¹。

R¹¹²、R¹¹³And R¹¹⁴Each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or a phenyl group.

*¹Is represented by the formula¹¹¹The connecting bond of (1).

Denotes a bond to a carbon atom. ]

Examples of the halogen atom include: fluorine atom, chlorine atom, bromine atom, iodine atom.

Examples of the alkyl group substituted with a halogen atom include a perfluoroalkyl group such as a trifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluoroisopropyl group, a perfluorobutyl group, a perfluorosec-butyl group, a perfluorotert-butyl group, a perfluoropentyl group, and a perfluorohexyl group. The number of carbon atoms of the alkyl group substituted with a halogen atom is usually 1 to 25.

As R¹¹¹Examples of the hydrocarbon group having 1 to 25 carbon atoms include: a straight-chain or branched alkyl group having 1 to 25 carbon atoms such as a methyl group, an ethyl group, a n-propyl group, an isopropyl group, a n-butyl group, a tert-butyl group, a sec-butyl group, a n-pentyl group, an isopentyl group, a n-hexyl group, an isohexyl group, a n-octyl group, an isooctyl group, a n-nonyl group, an isononyl group, a n-decyl group, an isodecyl group, a n-dodecyl group, an isododecyl group, an undecyl group, a lauryl group, a myri: cycloalkyl groups having 3 to 25 carbon atoms such as cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl; a cycloalkylalkyl group having 4 to 25 carbon atoms such as a cyclopropylmethyl group and a cyclohexylmethyl group; aryl groups having 6 to 25 carbon atoms such as phenyl, naphthyl, anthryl and biphenyl groups; aralkyl groups having 7 to 25 carbon atoms such as benzyl, phenethyl, naphthylmethyl and phenyl.

As R¹¹²、R¹¹³And R¹¹⁴Examples of the alkyl group having 1 to 6 carbon atoms include the group represented by the formula^1AThe alkyl group having 1 to 6 carbon atoms is the same as the alkyl group.

R¹¹¹Preferably an alkyl group having 4 to 25 carbon atoms, more preferably an alkyl group having 4 to 12 carbon atoms.

X¹preferably-CO-¹and-COO-)¹。

R⁶And R⁷Shown as electron withdrawingEach of the linear groups is independently preferably a cyano group or a group represented by the formula (I-1).

As R¹And R²The ring structures formed by bonding each other are those containing R¹And R²Examples of the nitrogen-containing ring structure of the nitrogen atom to be bonded include nitrogen-containing heterocycles having four to ten members. R¹And R²The ring structures formed by the mutual connection may be monocyclic or polycyclic. Specific examples thereof include a pyrrolidine ring, a pyrroline ring, an imidazolidine ring, an imidazoline ring, an oxazoline ring, a thiazoline ring, a piperidine ring, a morpholine ring, a piperazine ring, an indole ring, and an isoindole ring. R¹And R²The ring formed by bonding to each other may optionally have a substituent, and examples of the substituent include: alkyl groups having 1 to 12 carbon atoms such as methyl, ethyl, propyl, butyl, isobutyl, etc.; alkoxy groups having 1 to 12 carbon atoms such as methoxy, ethoxy, propoxy and butoxy groups.

As R²And R³The ring structures formed by bonding each other are those containing R²Examples of the nitrogen-containing ring structure of the nitrogen atom to be bonded include nitrogen-containing heterocycles having four to ten members. R²And R³The ring structures formed by the mutual connection may be monocyclic or polycyclic. Specifically, there may be mentioned a pyrrolidine ring, a pyrroline ring, an imidazolidine ring, an imidazoline ring, an oxazoline ring, a thiazoline ring, a piperidine ring, a morpholine ring, a piperazine ring, an indole ring, an isoindole ring and a ring structure represented by the following formula (I-3).

[ in the formula (I-3), X represents a nitrogen atom, an oxygen atom or a sulfur atom.

Ring W¹Represents a ring having a nitrogen atom and X as constituent elements.]

Ring W¹Preferably a five-membered ring or a six-membered ring having nitrogen atoms and X as constituent elements.

Specific examples of the ring structure represented by the formula (I-3) include the following rings.

R²And R³The ring structures bonded to each other may optionally have a substituent, and examples of the substituent include: alkyl groups having 1 to 12 carbon atoms such as methyl, ethyl, propyl, butyl, isobutyl, etc.; alkoxy groups having 1 to 12 carbon atoms such as methoxy, ethoxy, propoxy and butoxy groups.

R²And R³The ring structures bonded to each other are preferably ring structures represented by the following formula (I-4).

[ in the formula (I-4), R¹¹The same meaning as above is indicated. m2 represents an integer of 1 to 7.

R^11a、R^11b、R^11cAnd R^11dEach independently represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms.

Denotes a bond to a carbon atom. ]

m2 is preferably 2 or 3, more preferably 2.

As R²And R⁴Examples of the ring structure formed by bonding to each other include a nitrogen-containing ring structure having four to ten members, and preferably a nitrogen-containing ring structure having five to nine members. R²And R⁴The ring structures formed by bonding to each other may be monocyclic or polycyclic. These rings optionally have a substituent. Examples of such a ring structure include an azole ring, an indole ring, a pyrimidine ring, and the rings described below.

R²And R⁴The ring structures bonded to each other may optionally have a substituent, and examples of the substituent include: alkyl groups having 1 to 12 carbon atoms such as methyl, ethyl, propyl, butyl, isobutyl, etc.; methoxy, ethoxy, propoxyAn alkoxy group having 1 to 12 carbon atoms such as butoxy group; -NR such as amino, methylamino or dimethylamino^22AR^22BThe group shown (R)^22AAnd R^22BEach independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms); alkylthio groups having 1 to 12 carbon atoms such as a methylthio group, an ethylthio group, a propylthio group, a butylthio group, a pentylthio group, and the like; and a C4-9 heterocyclic group such as a pyrrolidinyl group, a piperidinyl group, or a morpholinyl group.

As R³And R⁶The ring structures formed by interconnection being R³－C＝C－C＝C－R⁶The ring structure forming the backbone of the ring. For example, phenyl group and the like are mentioned.

As R⁵And R⁷Examples of the ring structures formed by connecting the ring structures to each other include the following ring structures. R⁵And R⁷The ring structure formed by bonding to each other optionally has a substituent, and examples of the substituent include an alkyl group having 1 to 12 carbon atoms such as a methyl group, an ethyl group, a propyl group, a butyl group, and an isobutyl group; alkoxy groups having 1 to 12 carbon atoms such as methoxy, ethoxy, propoxy and butoxy groups.

As R⁶And R⁷Examples of the ring structures formed by connecting the two to each other include the ring structures described below. R⁶And R⁷The ring structures formed by bonding to each other may have a substituent (R in the following formula)₁～R₁₆) Examples of the substituent include alkyl groups having 1 to 12 carbon atoms such as methyl group, ethyl group, propyl group, butyl group, and isobutyl group; alkoxy groups having 1 to 12 carbon atoms such as methoxy, ethoxy, propoxy and butoxy; an ethylenically unsaturated group described later, and the like.

[ in the formula, a represents a bond to a carbon atom. ]

As R¹～R⁷As the ethylenically unsaturated group, there may be mentioned BAlkenyl, α -methylvinyl, acryloyl, methacryloyl, allyl, styryl and the group of formula (I-2).

*-R¹¹⁵-X²(I-2)

[ in the formula (I-2), X²Represents a vinyl group, an acryloyl group or a methacryloyl group.

R¹¹⁵Represents a C1-18 divalent aliphatic hydrocarbon group, and-CH contained in the aliphatic hydrocarbon group₂May be substituted by-O-, -CO-, -CS-or-NR¹¹⁶－。

R¹¹⁶Represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

Denotes a bond to a carbon atom or a nitrogen atom. ]

As R¹¹⁵Examples of the divalent aliphatic hydrocarbon group having 1 to 18 carbon atoms include alkane diyl groups having 1 to 18 carbon atoms such as a methylene group, an ethylene group, a propane-1, 3-diyl group, a propane-1, 2-diyl group, a butane-1, 4-diyl group, a pentane-1, 5-diyl group, a hexane-1, 6-diyl group, a butane-1, 3-diyl group, a 2-methylpropane-1, 2-diyl group, a pentane-1, 4-diyl group, and a 2-methylbutane-1, 4-diyl group: a cycloalkanediyl group having 3 to 18 carbon atoms such as a cyclopropanediyl group, a cyclobutanediyl group, a cyclopentanediyl group, a cyclohexanediyl group and the like, and preferably a divalent aliphatic hydrocarbon group having 1 to 12 carbon atoms.

As R¹¹⁶Examples of the alkyl group having 1 to 6 carbon atoms include the group represented by the formula^1AThe alkyl group having 1 to 6 carbon atoms is the same as the alkyl group.

R¹～R⁷The ethylenically unsaturated groups shown are each independently preferably a vinyl group, an acryloyl group, a methacryloyl group, and a group represented by the formula (I-2).

Preferably, R is⁶And R⁷Either one of them is an electron-withdrawing group.

Preferably, R is⁶And R⁷Any one of them is an ethylenically unsaturated group.

The structural unit derived from the compound represented by the formula (I) is preferably a structural unit derived from the compound represented by the formula (II).

R^11AEach independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

As R¹¹～R¹⁵Examples of the optionally substituted C1-25 aliphatic hydrocarbon group include¹The aliphatic hydrocarbon group having 1 to 25 carbon atoms, which may be substituted, is the same group.

As R¹¹～R¹⁵The aromatic hydrocarbon group having 6 to 15 carbon atoms which may be substituted includes R¹The aromatic hydrocarbon group having 6 to 15 carbon atoms, which may be substituted, is the same group.

As R¹¹～R¹⁵Examples of the heterocyclic ring include the heterocyclic ring with R¹The heterocyclic rings shown are the same heterocyclic rings.

As R¹⁶And R¹⁷Examples of the alkyl group having 1 to 25 carbon atoms include the group represented by the formula⁶The alkyl groups having 1 to 25 carbon atoms are the same.

As R¹⁶And R¹⁷Examples of the electron-withdrawing group include⁶The electron-withdrawing groups shown are the same.

As R^11AExamples of the alkyl group having 1 to 6 carbon atoms include the group represented by the formula^1AThe alkyl groups having 1 to 6 carbon atoms are the same.

As R¹²And R¹³Examples of the ring structure which can be formed by connecting R and R²And R³The ring structures are connected to each other to form the same ring structure. R¹²And R¹³The ring structure which can be formed by connecting them is preferably a single ring structure.

As R¹²And R¹⁴Examples of the ring structure which can be formed by connecting R and R²And R⁴The ring structures are connected to each other to form the same ring structure. R¹²And R¹⁴The ring structure which can be formed by connecting them is preferably a single ring structure. R¹²And R¹⁴The ring structure that can be formed by connecting them to each other is preferably an aromatic ring, and more preferably a pyrimidine ring structure.

R¹¹、R¹³And R¹⁵Independently of each other, the aliphatic hydrocarbon group is preferably an optionally substituted alkyl group having 1 to 25 carbon atoms, more preferably an optionally substituted alkyl group having 1 to 25 carbon atoms, and still more preferably an optionally substituted alkyl group having 1 to 12 carbon atoms.

In particular, as R¹¹The aliphatic hydrocarbon group is preferably an aliphatic hydrocarbon group having 1 to 10 carbon atoms, more preferably an alkyl group having 1 to 10 carbon atoms, and further preferably a methyl group.

Preferably, R is¹²And R¹⁴Each independently is an optionally substituted aliphatic hydrocarbon group having 1 to 25 carbon atoms, or R¹²And R¹⁴Are connected to each other to form a ring structure.

R¹²And R¹³Preferably, they are linked to each other to form a ring structure, and more preferably a ring structure represented by the above formula (I-4). Among the ring structures represented by the formula (I-4), preferred is a ring structure represented by the formula (I-4-1) or a ring structure represented by the formula (I-4-2),the ring structure represented by the formula (I-4-1) is particularly preferable.

Preferably, R is¹⁶And R¹⁷One of them is an ethylenically unsaturated group, and the other is an electron-withdrawing group.

R¹⁶And R¹⁷The electron-withdrawing groups are each independently preferably a cyano group, a nitro group, a fluoro group, a trifluoromethyl group, or a group represented by the formula (I-1). Cyano is particularly preferred.

R¹⁶And R¹⁷The ethylenically unsaturated groups shown are each independently preferably a vinyl group, an acryloyl group, a methacryloyl group, and a group represented by the formula (I-2). Further preferred is-CO-O- (CH)₂)n－X²(X²And n represents an integer of 1 to 10 (preferably an integer of 2 to 6). ).

As R¹²And R¹³The compound represented by the formula (II) which is linked to each other to form a ring structure is preferably a compound represented by the formula (II-A-1) or a compound represented by the formula (II-A-2). As R¹²And R¹⁴The compound represented by the formula (II) which is linked to each other to form a ring structure is preferably a compound represented by the formula (II-B-1).

[ formula (II-A-1), formula (II-A-2) and formula (II-B-1) wherein R¹¹、R¹⁴、R¹⁵、R¹⁶And R¹⁷Each represents the same meaning as above.

R^11e、R^11f、R^11g、R^11h、R^11k、R^11m、R¹¹ⁿEach independently represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms.

R^11qAnd R^11pEach independently represents a hydrogen atomAlkyl group having 1 to 12 carbon atoms, -NR^22AR^22BThe group shown (R)^22AAnd R^22BEach independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms) or a heterocycle.]

For example, the compound represented by the formula (II) in which the electron-withdrawing group is a cyano group can be obtained by reacting a compound represented by the following formula (I') with a compound represented by the formula (L).

[ in the formula, R²²²Represents a divalent linking group, X²Represents a polymerizable group.]

The reaction of the compound of formula (I') with the compound of formula (L) can be promoted by any conditions used for the general Knoevenagel condensation. For example, it is preferably carried out in the presence of a base or a carboxylic acid anhydride. Examples of the base include: triethylamine, N-diisopropylethylamine, pyridine, piperidine, pyrrolidine, proline, N-dimethylaminopyridine, imidazole, sodium hydroxide, potassium carbonate, sodium bicarbonate, potassium tert-butoxide, sodium hydride and the like. Examples of the carboxylic anhydride include acetic anhydride, succinic anhydride, phthalic anhydride, maleic anhydride, and benzoic anhydride. The amount of the base used is preferably 0.1 to 10 mol based on 1 mol of the compound represented by the formula (I'). The amount of acetic anhydride used is preferably 0.2 to 5 mol based on 1 mol of the compound represented by the formula (I').

The reaction of the compound represented by the formula (I') with the compound represented by the formula (L) is preferably carried out in an organic solvent. Examples of the organic solvent include toluene, acetonitrile, dichloromethane, and chloroform.

The reaction of the compound represented by the formula (I ') with the compound represented by the formula (L) can be carried out by mixing the compound represented by the formula (I') with the compound represented by the formula (L).

The reaction temperature of the compound represented by the formula (I') and the compound represented by the formula (L) is preferably-40 to 130 ℃, and the reaction time is preferably 1 to 24 hours.

The compound represented by the formula (I') can be synthesized, for example, according to the method described in Japanese unexamined patent publication No. 2014-194508.

The compound represented by the formula (L) can be obtained, for example, by reacting cyanoacetic acid with a hydroxyalkyl acrylate.

The amount of the cyanoacetic acid to be used is preferably 0.5 to 3 moles based on 1 mole of the hydroxyalkyl acrylate.

The reaction of cyanoacetic acid with hydroxyalkyl acrylate may be carried out using any esterification catalyst used in general esterification reactions, preferably in the presence of a base and a carbodiimide condensing agent. Examples of the base include: triethylamine, diisopropylethylamine, pyridine, piperidine, pyrrolidine, proline, N-dimethylaminopyridine, imidazole, sodium hydroxide, potassium carbonate, sodium bicarbonate, potassium tert-butoxide, sodium hydride and the like. Examples of the carbodiimide condensing agent include N, N-dicyclohexylcarbodiimide, N-diisopropylcarbodiimide, and 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride. The amount of the base used is preferably 0.5 to 5 mol based on 1 mol of cyanoacetic acid.

The reaction of cyanoacetic acid with hydroxyalkyl acrylate is preferably carried out in an organic solvent. Examples of the organic solvent include acetonitrile, isopropanol, toluene, chloroform, and dichloromethane.

The reaction of the cyanoacetic acid with the hydroxyalkyl acrylate is carried out by mixing the cyanoacetic acid with the hydroxyalkyl acrylate.

The reaction temperature of the cyanoacetic acid and the hydroxyalkyl acrylate is preferably-40 to 130 ℃, and the reaction time is preferably 1 to 24 hours.

Examples of the compound having a polymerizable group and a merocyanine structure include the compounds described below.

The resin (a) may be a homopolymer having a structural unit having a merocyanine structure in a side chain, or may be a copolymer comprising a structural unit having a merocyanine structure in a side chain and another structural unit. The resin (a) is preferably a copolymer.

Examples of the structural unit that the resin (a) may contain in addition to the structural unit having a merocyanine structure in the side chain include structural units described in the following group a.

[ in the formula, R^a1Represents a divalent hydrocarbon group.

R^c1And R^c2Each independently represents a divalent hydrocarbon group.]

Examples of the (meth) acrylate include: linear alkyl esters of (meth) acrylic acid such as methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, n-pentyl (meth) acrylate, n-hexyl (meth) acrylate, n-heptyl (meth) acrylate, n-octyl (meth) acrylate, n-nonyl (meth) acrylate, n-decyl (meth) acrylate, n-dodecyl (meth) acrylate, lauryl (meth) acrylate, and stearyl (meth) acrylate;

branched alkyl esters of (meth) acrylic acid such as isopropyl (meth) acrylate, isobutyl (meth) acrylate, tert-butyl (meth) acrylate, isoamyl (meth) acrylate, isohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate, isostearyl (meth) acrylate, and isoamyl (meth) acrylate;

alkyl esters having an alicyclic skeleton of (meth) acrylic acid such as cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, adamantyl (meth) acrylate, dicyclopentanyl (meth) acrylate, cyclododecyl (meth) acrylate, methylcyclohexyl (meth) acrylate, trimethylcyclohexyl (meth) acrylate, t-butylcyclohexyl (meth) acrylate, and α -cyclohexylethoxyacrylate;

aromatic ring skeleton-containing esters of (meth) acrylic acid such as phenyl (meth) acrylate;

and so on.

The structural unit derived from a (meth) acrylate may be a substituent-containing alkyl (meth) acrylate obtained by introducing a substituent to an alkyl group in an alkyl (meth) acrylate. The substituent of the alkyl (meth) acrylate having a substituent is a group in which a hydrogen atom of an alkyl group is substituted, and specific examples thereof include a phenyl group, an alkoxy group, and a phenoxy group. Specific examples of the alkyl (meth) acrylate containing a substituent include 2-methoxyethyl (meth) acrylate, ethoxymethyl (meth) acrylate, phenoxyethyl (meth) acrylate, 2- (2-phenoxyethoxy) ethyl (meth) acrylate, phenoxydiethylene glycol (meth) acrylate, and phenoxypoly (ethylene glycol) meth (acrylate).

These (meth) acrylates may be used alone or in combination of two or more.

The resin (a) of the present invention preferably contains: a structural unit derived from an alkyl (meth) acrylate (a1) having a homopolymer glass transition temperature Tg of less than 0 ℃ among alkyl (meth) acrylates, and a structural unit derived from an alkyl (meth) acrylate (a2) having a homopolymer Tg of 0 ℃ or higher. This is advantageous in improving the high-temperature durability of the adhesive layer. The Tg of the homopolymer of the alkyl (meth) acrylate can be obtained, for example, from literature values of POLYMER HANDBOOK (Wiley-Interscience) and the like.

Specific examples of the alkyl (meth) acrylate (a1) include: alkyl (meth) acrylates having an alkyl group of about 2 to 12 carbon atoms such as ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, n-pentyl acrylate, n-hexyl acrylate, isohexyl acrylate, n-heptyl acrylate, n-octyl acrylate, isooctyl acrylate, 2-ethylhexyl acrylate, n-nonyl acrylate, isononyl acrylate, n-decyl acrylate, isodecyl acrylate, and n-dodecyl acrylate.

The alkyl (meth) acrylate (a1) may be used in only 1 kind, or may be used in combination of 2 or more kinds. Among them, n-butyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate and the like are preferable from the viewpoint of the followability and reworkability when laminated on the optical film.

The alkyl (meth) acrylate (a2) is an alkyl (meth) acrylate other than the alkyl (meth) acrylate (a 1). Specific examples of the alkyl (meth) acrylate (a2) include: methyl acrylate, cyclohexyl acrylate, isobornyl acrylate, stearyl acrylate, t-butyl acrylate, and the like.

The alkyl (meth) acrylate (a2) may be used in only 1 kind, or may be used in combination of 2 or more kinds. Among them, the alkyl (meth) acrylate (a2) preferably includes methyl acrylate, cyclohexyl acrylate, isobornyl acrylate, and the like, and more preferably includes methyl acrylate, from the viewpoint of high-temperature durability.

Further, as the structural unit derived from a (meth) acrylate, a structural unit derived from a (meth) acrylate having a polar functional group can be also cited.

Examples of the (meth) acrylate monomer having a polar functional group include:

1-hydroxymethyl (meth) acrylate, 1-hydroxyethyl (meth) acrylate, 1-hydroxyheptyl (meth) acrylate, 1-hydroxybutyl (meth) acrylate, 1-hydroxypentyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 2-hydroxypentyl (meth) acrylate, 2-hydroxyhexyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 3-hydroxypentyl (meth) acrylate, 3-hydroxyhexyl (meth) acrylate, 3-hydroxyheptyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 4-hydroxypentyl (meth) acrylate, 4-hydroxyhexyl (meth) acrylate, 4-hydroxyheptyl (meth) acrylate, hydroxy-heptyl (meth) acrylate, hydroxy-hexyl (meth) acrylate, hydroxy-, 4-hydroxyoctyl (meth) acrylate, 2-chloro-2-hydroxypropyl (meth) acrylate, 3-chloro-2-hydroxypropyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, 5-hydroxypentyl (meth) acrylate, 5-hydroxyhexyl (meth) acrylate, 5-hydroxyheptyl (meth) acrylate, 5-hydroxyoctyl (meth) acrylate, 5-hydroxynonyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 6-hydroxyheptyl (meth) acrylate, 6-hydroxyoctyl (meth) acrylate, 6-hydroxynonyl (meth) acrylate, 6-hydroxydecyl (meth) acrylate, 7-hydroxyheptyl (meth) acrylate, 7-hydroxyoctyl (meth) acrylate, 7-hydroxynonyl (meth) acrylate, 7-hydroxydecyl (meth) acrylate, 7-hydroxyundecyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 8-hydroxynonyl (meth) acrylate, 8-hydroxydecyl (meth) acrylate, 8-hydroxyundecyl (meth) acrylate, 8-hydroxydodecyl (meth) acrylate, 9-hydroxynonyl (meth) acrylate, 9-hydroxydecyl (meth) acrylate, 9-hydroxyundecyl (meth) acrylate, 9-hydroxydodecyl (meth) acrylate, 9-hydroxytridecyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 10-hydroxyundecyl (meth) acrylate, 10-hydroxydodecyl (meth) acrylate, 10-hydroxytridecyl acrylate, 10-hydroxytetradecyl (meth) acrylate, 11-hydroxyundecyl (meth) acrylate, 11-hydroxydodecyl (meth) acrylate, and mixtures thereof, And (meth) acrylic acid alkyl esters having a hydroxyl group such as 11-hydroxytridecyl (meth) acrylate, 11-hydroxytetradecyl (meth) acrylate, 11-hydroxypentadecyl (meth) acrylate, 12-hydroxydodecyl (meth) acrylate, 12-hydroxytridecyl (meth) acrylate, 12-hydroxytetradecyl (meth) acrylate, 13-hydroxypentadecyl (meth) acrylate, 13-hydroxytetradecyl (meth) acrylate, 13-hydroxypentadecyl (meth) acrylate, 14-hydroxytetradecyl (meth) acrylate, 14-hydroxypentadecyl (meth) acrylate, 15-hydroxypentadecyl (meth) acrylate, and 15-hydroxyheptadecyl (meth) acrylate.

Examples of the styrene monomer include: styrene; alkylstyrenes such as methylstyrene, dimethylstyrene, trimethylstyrene, ethylstyrene, diethylstyrene, triethylstyrene, propylstyrene, butylstyrene, hexylstyrene, heptylstyrene, octylstyrene and the like; halogenated styrenes such as fluorostyrene, chlorostyrene, bromostyrene, dibromostyrene, iodostyrene, etc.; nitrostyrene; acetyl styrene; a methoxystyrene; and divinylbenzene.

Examples of the vinyl monomer include: vinyl esters of fatty acids such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl 2-ethylhexanoate, and vinyl laurate; vinyl halides such as vinyl chloride and vinyl bromide; vinylidene halides such as vinylidene chloride; nitrogen-containing heteroaromatic vinyl groups such as vinylpyridine, vinylpyrrolidone and vinylcarbazole; conjugated dienes such as butadiene, isoprene and chloroprene; and unsaturated nitriles such as acrylonitrile and methacrylonitrile.

The compound which leads to the structural unit represented by the formula (a) can be synthesized, for example, by reacting a diisocyanate compound with a polyol.

The compound which leads to the structural unit represented by the formula (b) can be synthesized, for example, by reacting a halosilane or a silane having a hydroxyl group.

The compound that leads to the structural unit represented by formula (c) can be synthesized, for example, by the reaction of a polycarboxylic acid with a polyhydric alcohol, or the like.

The structural unit selected from the structural units described in group a is preferably a structural unit derived from a (meth) acrylate. The structural units derived from (meth) acrylic acid esters are preferably alkyl (meth) acrylates and alkyl (meth) acrylates having hydroxyl groups.

The resin (a) of the present invention may further contain another structural unit (sometimes referred to as structural unit (aa)). Specifically, there may be mentioned: a structural unit derived from a (meth) acrylamide monomer, a structural unit derived from a monomer having a carboxyl group, a structural unit derived from a monomer having a heterocyclic group, a structural unit derived from a monomer having a substituted or unsubstituted amino group, and the like.

Examples of the (meth) acrylamide monomer include: n-hydroxymethyl (meth) acrylamide, N- (2-hydroxyethyl) (meth) acrylamide, N- (3-hydroxypropyl) (meth) acrylamide, N- (4-hydroxybutyl) (meth) acrylamide, N- (5-hydroxypentyl) (meth) acrylamide, N- (6-hydroxyhexyl) (meth) acrylamide, N-dimethyl (meth) acrylamide, N-diethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N- (3-dimethylaminopropyl) (meth) acrylamide, N- (1, 1-dimethyl-3-oxobutyl) (meth) acrylamide, N- [ 2- (2-oxo-1-imidazolidinyl) ethyl ] (meth) acrylamide, 2-acrylamido-2-methyl-1-propanesulfonic acid, N- (methoxymethyl) acrylamide, N- (ethoxymethyl) (meth) acrylamide, N- (propoxymethyl) (meth) acrylamide, N- (1-methylethoxymethyl) (meth) acrylamide, N- (1-methylpropoxymethyl) (meth) acrylamide, N- (2-methylpropoxymethyl) (meth) acrylamide, N- (butoxymethyl) (meth) acrylamide, N- (1, 1-dimethylethoxymethyl) (meth) acrylamide, N- (2-methoxyethyl) (meth) acrylamide, N- (2-ethoxyethyl) (meth) acrylamide, N- (2-propoxyethyl) (meth) acrylamide, N- [ 2- (1-methylethoxy) ethyl ] (meth) acrylamide, N- [ 2- (1-methylpropoxy) ethyl ] (meth) acrylamide, N- (1-methylethoxy) ethyl (meth) acrylamide, N- (1-methylpropoxy) ethyl (meth) acrylamide, n- [ 2- (2-methylpropoxy) ethyl ] (meth) acrylamide, N- (2-butoxyethyl) (meth) acrylamide, N- [ 2- (1, 1-dimethylethoxy) ethyl ] (meth) acrylamide, and the like. Among them, N- (methoxymethyl) acrylamide, N- (ethoxymethyl) acrylamide, N- (propoxymethyl) acrylamide, N- (butoxymethyl) acrylamide and N- (2-methylpropoxymethyl) acrylamide are preferable.

Examples of the monomer having a carboxyl group include (meth) acrylic acid, carboxyalkyl (meth) acrylates (e.g., carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate), maleic acid, maleic anhydride, fumaric acid, crotonic acid, and the like, and acrylic acid is preferable.

Examples of the monomer having a heterocyclic group include: acryloyl morpholine, vinyl caprolactam, N-vinyl-2-pyrrolidone, vinyl pyridine, tetrahydrofurfuryl (meth) acrylate, caprolactone-modified tetrahydrofurfuryl acrylate, 3, 4-epoxycyclohexylmethyl (meth) acrylate, glycidyl (meth) acrylate, 2, 5-dihydrofuran, and the like.

Examples of the monomer having a substituted or unsubstituted amino group include: aminoethyl (meth) acrylate, N-dimethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, and the like.

As the structural unit (aa) other than the structural unit having a merocyanine structure and the structural unit selected from group a, a monomer having a carboxyl group is preferable.

The content of the structural unit having a merocyanine structure in a side chain is preferably 0.01 to 50 parts by mass, more preferably 0.1 to 20 parts by mass, and still more preferably 0.5 to 10 parts by mass, based on 100 parts by mass of all the structural units contained in the resin (a).

The content of at least 1 kind of structural unit selected from the structural units described in group a is preferably 50 parts by mass or more, and more preferably 60 to 99.99 parts by mass, based on 100 parts by mass of all the structural units of the resin (a).

When the resin (a) contains the structural unit (aa), it is preferably 20 parts by mass or less, more preferably 0.5 parts by mass or more and 15 parts by mass or less, further preferably 0.5 parts by mass or more and 10 parts by mass or less, and particularly preferably 1 part by mass or more and 7 parts by mass or less, relative to 100 parts by mass of all the structural units of the resin (a).

When the resin (a) contains a structural unit derived from an alkyl (meth) acrylate having a hydroxyl group, the content of the structural unit is preferably 20 parts by mass or less, more preferably 0.5 parts by mass or more and 15 parts by mass or less, further preferably 0.5 parts by mass or more and 10 parts by mass or less, and particularly preferably 1 part by mass or more and 7 parts by mass or less, per 100 parts by mass of the total structural units of the resin (a).

From the viewpoint of preventing a large increase in the peeling force of a separator that can be laminated on the outer surface of the pressure-sensitive adhesive layer, it is preferable that the separator contains substantially no monomer having an amino group. The term "substantially not included" means that the amount is 0.1 parts by mass or less per 100 parts by mass of all the structural units constituting the resin (a).

From the viewpoint of reactivity of the resin (a) with the crosslinking agent (B) described later, the resin (a) preferably contains a structural unit derived from an alkyl (meth) acrylate having a hydroxyl group or a structural unit derived from a monomer having a carboxyl group, and more preferably contains both a structural unit derived from an alkyl (meth) acrylate having a hydroxyl group and a structural unit derived from a monomer having a carboxyl group. As the alkyl (meth) acrylate having a hydroxyl group, 2-hydroxyethyl acrylate, 3-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 5-hydroxypentyl acrylate, and 6-hydroxyhexyl acrylate are preferable. In particular, good durability can be obtained by using 2-hydroxyethyl acrylate, 4-hydroxybutyl acrylate and 5-hydroxypentyl acrylate. As the monomer having a carboxyl group, acrylic acid is preferably used.

The weight average molecular weight (Mw) of the resin (a) of the present invention is preferably 30 to 250 ten thousand, and more preferably 50 to 250 ten thousand. When the weight average molecular weight is 30 ten thousand or more, the durability of the pressure-sensitive adhesive layer in a high-temperature environment is improved, and defects such as peeling of an adherend from the pressure-sensitive adhesive layer by lifting and cohesive failure of the pressure-sensitive adhesive layer are easily suppressed. When the weight average molecular weight is 250 ten thousand or less, it is advantageous from the viewpoint of coatability when the adhesive composition is processed into, for example, a sheet form (applied to a substrate). From the viewpoint of satisfying both the durability of the pressure-sensitive adhesive layer and the coatability of the pressure-sensitive adhesive composition, the weight average molecular weight is preferably 60 to 180 ten thousand, more preferably 70 to 170 ten thousand, and particularly preferably 100 to 160 ten thousand. The molecular weight distribution (Mw/Mn) represented by the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is usually 2 to 10, preferably 3 to 8. The weight average molecular weight can be analyzed by gel permeation chromatography and is a value in terms of standard polystyrene.

When the resin (A) of the present invention is dissolved in ethyl acetate to form a 20 mass% solution, the viscosity at 25 ℃ is preferably 20 pas or less, and more preferably 0.1 to 15 pas. A viscosity in this range is advantageous from the viewpoint of coatability when the adhesive composition is applied to a substrate. The viscosity can be measured by a brookfield viscometer.

The resin (a) of the present invention can be produced by a known method such as solution polymerization, bulk polymerization, suspension polymerization, or emulsion polymerization, and the solution polymerization is particularly preferred. Examples of the solution polymerization method include: a method comprising mixing a monomer and an organic solvent, adding a thermal polymerization initiator under a nitrogen atmosphere, and stirring at a temperature of 40 to 90 ℃, preferably 50 to 80 ℃ for about 3 to 15 hours. In order to control the reaction, a monomer or a thermal polymerization initiator may be continuously or intermittently added during the polymerization. The monomer and the thermal initiator may be added to an organic solvent.

As the polymerization initiator, a thermal polymerization initiator, a photopolymerization initiator, or the like can be used. Examples of the photopolymerization initiator include 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone and the like. Examples of the thermal polymerization initiator include: azo compounds such as 2, 2 ' -azobisisobutyronitrile, 2 ' -azobis (2-methylbutyronitrile), 1 ' -azobis (cyclohexane-1-carbonitrile), 2 ' -azobis (2, 4-dimethylvaleronitrile), 2 ' -azobis (2, 4-dimethyl-4-methoxyvaleronitrile), dimethyl-2, 2 ' -azobis (2-methylpropionate), and 2, 2 ' -azobis (2-hydroxymethylpropionitrile); organic peroxides such as lauryl peroxide, t-butyl hydroperoxide, benzoyl peroxide, t-butyl peroxybenzoate, cumene hydroperoxide, diisopropyl peroxydicarbonate, dipropyl peroxydicarbonate, t-butyl peroxyneodecanoate, t-butyl peroxypivalate, and (3, 5, 5-trimethylhexanoyl) peroxide; and inorganic peroxides such as potassium persulfate, ammonium persulfate, and hydrogen peroxide. In addition, redox initiators using a combination of a peroxide and a reducing agent, and the like can also be used.

The proportion of the polymerization initiator is about 0.001 to 5 parts by mass relative to 100 parts by mass of the total amount of the monomers constituting the resin (A). Polymerization methods using active energy rays (e.g., ultraviolet rays) can also be used for polymerization of the resin (a).

Examples of the organic solvent include: aromatic hydrocarbons such as toluene and xylene; esters such as ethyl acetate and butyl acetate; aliphatic alcohols such as propanol and isopropanol; ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone.

The resin (a) is preferably a resin satisfying the following formula (1), and more preferably a resin further satisfying the following formula (2).

ε(405)≥0.02 (1)

ε(405)/ε(440)≥5 (2)

The gram absorbance coefficient of the resin (a) can be measured by the method described in examples.

The larger the value of ε (405) of resin (A), the more easily it absorbs light having a wavelength of 405nm, and the value of ε (405) is preferably 0.02L/(g cm) or more, more preferably 0.1L/(g cm) or more, still more preferably 0.2L/(g cm) or more, and usually 10L/(g cm) or less.

When the adhesive composition containing the resin (a) is applied to a display device (FPD: flat panel display) such as an organic electroluminescent display (organic EL display device) or a liquid crystal display device, if ∈ (405) of the resin (a) is 0.02L/(g · cm) or more, the absorption performance of visible light in the vicinity of 400nm is good, and thus degradation of a retardation film or an organic EL light-emitting element used in the display device such as the organic EL display device or the liquid crystal display device due to visible light can be suppressed.

The larger the value of ε (405)/ε (440) of the resin (A), the more selectively light having a wavelength of around 400nm can be absorbed. The value of ε (405)/ε (440) is preferably 5 or more, more preferably 50 or more, still more preferably 75 or more, and particularly preferably 100 or more.

When epsilon (405)/epsilon (440) of the resin (a) is 5 or more, when the adhesive composition containing the resin (a) is applied to a display device (FPD: flat panel display) such as an organic EL display device or a liquid crystal display device, light near 405nm can be absorbed without impairing the color expression of the display device, and light degradation of a retardation film, an organic EL element, or the like can be suppressed.

< adhesive composition >

The adhesive composition of the present invention contains a resin (a). The adhesive composition of the present invention may further contain a crosslinking agent (B), a silane compound (D), an antistatic agent, and the like.

The content of the resin (a) is usually 60 to 99.99 mass%, preferably 70 to 99.9 mass%, and more preferably 80 to 99.7 mass% in 100 mass% of the solid content of the binder composition.

The adhesive composition of the present invention may contain a crosslinking agent (B).

Examples of the crosslinking agent (B) include: isocyanate crosslinking agents, epoxy crosslinking agents, aziridine crosslinking agents, metal chelate crosslinking agents, and the like, and particularly isocyanate crosslinking agents are preferable from the viewpoints of the pot life of the adhesive composition, the durability of the adhesive layer, the crosslinking rate, and the like.

The isocyanate compound is preferably a compound having at least 2 isocyanate groups (-NCO) in the molecule, and examples thereof include aliphatic isocyanate compounds (e.g., hexamethylene diisocyanate), alicyclic isocyanate compounds (e.g., isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate), aromatic isocyanate compounds (e.g., toluene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, triphenylmethane triisocyanate, and the like). The crosslinking agent (B) may be an adduct (adduct) of the isocyanate compound with a polyol compound [ for example, an adduct of glycerin, trimethylolpropane or the like ], an isocyanurate compound, a biuret compound, a urethane prepolymer type isocyanate compound obtained by addition reaction with a polyether polyol, a polyester polyol, an acryl polyol, a polybutadiene polyol, a polyisoprene polyol or the like, or the like. The crosslinking agent (B) may be used alone or in combination of two or more. Among them, typically, aromatic isocyanate compounds (e.g., toluene diisocyanate, xylylene diisocyanate), aliphatic isocyanate compounds (e.g., hexamethylene diisocyanate), adducts thereof based on polyol compounds (e.g., glycerin, trimethylolpropane), or isocyanurates are exemplified. When the crosslinking agent (B) is an aromatic isocyanate-based compound and/or an adduct thereof based on a polyol compound or an isocyanurate compound, the durability of the adhesive layer can be improved, probably because it is advantageous to form an optimum crosslinking density (or crosslinking structure). In particular, when the adhesive layer is a toluene diisocyanate-based compound and/or an adduct thereof based on a polyol compound, durability can be improved even when the adhesive layer is applied to a polarizing plate, for example.

The content of the crosslinking agent (B) is usually 0.01 to 15 parts by mass, preferably 0.05 to 10 parts by mass, and more preferably 0.1 to 5 parts by mass, based on 100 parts by mass of the resin (A).

The adhesive composition of the present invention may further contain a silane compound (D).

Examples of the silane compound (D) include: vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylethoxydimethylsilane, 2- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane and the like.

The silane compound (D) may be a silicone oligomer. Specific examples of the silicone oligomer are described below when the monomers are combined with each other.

Mercaptopropyl-containing oligomers such as 3-mercaptopropyltrimethoxysilane-tetramethoxysilane oligomer, 3-mercaptopropyltrimethoxysilane-tetraethoxysilane oligomer, 3-mercaptopropyltriethoxysilane-tetramethoxysilane oligomer, and 3-mercaptopropyltriethoxysilane-tetraethoxysilane oligomer; mercapto methyl group-containing oligomers such as mercapto methyltrimethoxysilane-tetramethoxysilane oligomer, mercapto methyltrimethoxysilane-tetraethoxysilane oligomer, mercapto methyltriethoxysilane-tetramethoxysilane oligomer, and mercapto methyltriethoxysilane-tetraethoxysilane oligomer; 3-glycidoxypropyl group-containing copolymers such as 3-glycidoxypropyltrimethoxysilane-tetramethoxysilane copolymer, 3-glycidoxypropyltrimethoxysilane-tetraethoxysilane copolymer, 3-glycidoxypropyltriethoxysilane-tetramethoxysilane copolymer, 3-glycidoxypropyltriethoxysilane-tetraethoxysilane copolymer, 3-glycidoxypropylmethyldimethoxysilane-tetramethoxysilane copolymer, 3-glycidoxypropylmethyldimethoxysilane-tetraethoxysilane copolymer, 3-glycidoxypropylmethyldiethoxysilane-tetramethoxysilane copolymer and 3-glycidoxypropylmethyldiethoxysilane-tetraethoxysilane copolymer; methacryloxypropyl-containing oligomers such as 3-methacryloxypropyltrimethoxysilane-tetramethoxysilane oligomer, 3-methacryloxypropyltrimethoxysilane-tetraethoxysilane oligomer, 3-methacryloxypropyltriethoxysilane-tetramethoxysilane oligomer, 3-methacryloxypropyltriethoxysilane-tetraethoxysilane oligomer, 3-methacryloxypropylmethyldimethoxysilane-tetramethoxysilane oligomer, 3-methacryloxypropylmethyldimethoxysilane-tetraethoxysilane oligomer, 3-methacryloxypropylmethyldiethoxysilane-tetramethoxysilane oligomer, and 3-methacryloxypropylmethyldiethoxysilane-tetraethoxysilane oligomer; acryloxypropyl-containing oligomers such as 3-acryloxypropyltrimethoxysilane-tetramethoxysilane oligomer, 3-acryloxypropyltrimethoxysilane-tetraethoxysilane oligomer, 3-acryloxypropyltriethoxysilane-tetramethoxysilane oligomer, 3-acryloxypropyltriethoxysilane-tetraethoxysilane oligomer, 3-acryloxypropylmethyldimethoxysilane-tetramethoxysilane oligomer, 3-acryloxypropylmethyldimethoxysilane-tetraethoxysilane oligomer, 3-acryloxypropylmethyldiethoxysilane-tetramethoxysilane oligomer, and 3-acryloxypropylmethyldiethoxysilane-tetraethoxysilane oligomer; vinyl group-containing oligomers such as vinyltrimethoxysilane-tetramethoxysilane oligomer, vinyltrimethoxysilane-tetraethoxysilane oligomer, vinyltriethoxysilane-tetramethoxysilane oligomer, vinyltriethoxysilane-tetraethoxysilane oligomer, vinylmethyldimethoxysilane-tetramethoxysilane oligomer, vinylmethyldimethoxysilane-tetraethoxysilane oligomer, vinylmethyldiethoxysilane-tetramethoxysilane oligomer, and vinylmethyldiethoxysilane-tetraethoxysilane oligomer; amino group-containing copolymers such as 3-aminopropyltrimethoxysilane-tetramethoxysilane copolymer, 3-aminopropyltrimethoxysilane-tetraethoxysilane copolymer, 3-aminopropyltriethoxysilane-tetramethoxysilane copolymer, 3-aminopropyltriethoxysilane-tetraethoxysilane copolymer, 3-aminopropylmethyldimethoxysilane-tetramethoxysilane copolymer, 3-aminopropylmethyldimethoxysilane-tetraethoxysilane copolymer, 3-aminopropylmethyldiethoxysilane-tetramethoxysilane copolymer and 3-aminopropylmethyldiethoxysilane-tetraethoxysilane copolymer.

The silane compound (D) may be a silane compound represented by the following formula (D1).

(wherein A represents a C1-20 alkanediyl group or a C3-20 divalent alicyclic hydrocarbon group, -CH constituting the alkanediyl group and the alicyclic hydrocarbon group₂Optionally substituted by-O-or-CO-, R⁴¹Represents an alkyl group having 1 to 5 carbon atoms, R⁴²、R⁴³、R⁴⁴、R⁴⁵And R⁴⁶Each independently represents an alkyl group having 1 to 5 carbon atoms or an alkoxy group having 1 to 5 carbon atoms. )

Examples of the C1-20 alkanediyl group represented by A include: methylene, 1, 2-ethanediyl, 1, 3-propanediyl, 1, 4-butanediyl, 1, 5-pentanediyl, 1, 6-hexanediyl, 1, 7-heptanediyl, 1, 8-octanediyl, 1, 9-nonanediyl, 1, 10-decanediyl, 1, 12-dodecanediyl, 1, 14-tetradecanediyl, 1, 16-hexadecanediyl, 1, 18-octadecanediyl and 1, 20-eicosanediyl. Examples of the divalent alicyclic hydrocarbon group having 3 to 20 carbon atoms include a1, 3-cyclopentanediyl group and a1, 4-cyclohexanediyl group. as-CH constituting the alkanediyl group and the alicyclic hydrocarbon group₂Examples of the group in which-is replaced by-O-or-CO-, include-CH₂CH₂－O－CH₂CH₂－、－CH₂CH₂－O－CH₂CH₂－O－CH₂CH₂－、－CH₂CH₂－O－CH₂CH₂－O－CH₂CH₂－O－CH₂CH₂－、－CH₂CH₂－CO－O－CH₂CH₂－、－CH₂CH₂－O－CH₂CH₂－CO－O－CH₂CH₂－、－CH₂CH₂CH₂CH₂－O－CH₂CH₂-and-CH₂CH₂CH₂CH₂－O－CH₂CH₂CH₂CH₂－。

As R⁴¹～R⁴⁵Examples of the alkyl group having 1 to 5 carbon atoms include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl and pentyl, and R is⁴²～R⁴⁵Examples of the alkoxy group having 1 to 5 carbon atoms include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, an isobutoxy group, a tert-butoxy group and a pentyloxy group.

Examples of the silane compound represented by the formula (d1) include (trimethoxysilyl) methane, 1, 2-bis (trimethoxysilyl) ethane, 1, 2-bis (triethoxysilyl) ethane, 1, 3-bis (trimethoxysilyl) propane, 1, 3-bis (triethoxysilyl) propane, 1, 4-bis (trimethoxysilyl) butane, 1, 4-bis (triethoxysilyl) butane, 1, 5-bis (trimethoxysilyl) pentane, 1, 5-bis (triethoxysilyl) pentane, 1, 6-bis (trimethoxysilyl) hexane, 1, 6-bis (triethoxysilyl) hexane, 1, 6-bis (tripropoxysilyl) hexane, 1, 8-bis (trimethoxysilyl) octane, 1, 8-bis (triethoxysilyl) octane, and the like, Bis (tri-C1-5 alkoxysilyl) C1-10 alkanes such as 1, 8-bis (tripropoxysilyl) octane; bis (di-C1-5 alkoxy C1-5 alkylsilyl) C1-10 alkanes such as bis (dimethoxymethylsilyl) methane, 1, 2-bis (dimethoxymethylsilyl) ethane, 1, 2-bis (dimethoxyethylsilyl) ethane, 1, 4-bis (dimethoxymethylsilyl) butane, 1, 4-bis (dimethoxyethylsilyl) butane, 1, 6-bis (dimethoxymethylsilyl) hexane, 1, 6-bis (dimethoxyethylsilyl) hexane, 1, 8-bis (dimethoxymethylsilyl) octane and 1, 8-bis (dimethoxyethylsilyl) octane; and bis (mono C1-5 alkoxydiC 1-5 alkylsilyl) C1-10 alkanes such as 1, 6-bis (methoxydimethylsilyl) hexane and 1, 8-bis (methoxydimethylsilyl) octane. Among them, bis (tri C1-3 alkoxysilyl) C1-10 alkanes such as 1, 2-bis (trimethoxysilyl) ethane, 1, 3-bis (trimethoxysilyl) propane, 1, 4-bis (trimethoxysilyl) butane, 1, 5-bis (trimethoxysilyl) pentane, 1, 6-bis (trimethoxysilyl) hexane, 1, 8-bis (trimethoxysilyl) octane and the like are preferable, and 1, 6-bis (trimethoxysilyl) hexane and 1, 8-bis (trimethoxysilyl) octane are particularly preferable.

The content of the silane compound (D) is usually 0.01 to 10 parts by mass, preferably 0.03 to 5 parts by mass, more preferably 0.05 to 2 parts by mass, and still more preferably 0.1 to 1 part by mass, based on 100 parts by mass of the resin (a).

The adhesive composition may further comprise an antistatic agent.

Examples of the antistatic agent include a surfactant, a silicone compound, a conductive polymer, an ionic compound, and the like, and an ionic compound is preferable. The ionic compound may be a conventional ionic compound. Examples of the cation component constituting the ionic compound include an organic cation and an inorganic cation. Examples of the organic cation include a pyridinium cation, a pyrrolidinium cation, a piperidinium cation, an imidazolium cation, an ammonium cation, a sulfonium cation, and a phosphonium cation. Examples of the inorganic cation include alkali metal cations such as lithium cation, potassium cation, sodium cation, and cesium cation, and alkaline earth metal cations such as magnesium cation and calcium cation. In particular, from the viewpoint of compatibility with the (meth) acrylic resin, a pyridinium cation, an imidazolium cation, a pyrrolidinium cation, a lithium cation, and a potassium cation are preferable. As a constitutionThe anionic component of the ionic compound may be any of inorganic anions and organic anions, and is preferably an anionic component containing a fluorine atom from the viewpoint of antistatic performance. Examples of the anion component containing a fluorine atom include hexafluorophosphate anion (PF)₆ ^－) Bis (trifluoromethanesulfonyl) imide anion [ (CF)₃SO₂)₂N^－]Bis (fluorosulfonyl) imide anion [ (FSO)₂)₂N^－]Tetrakis (pentafluorophenyl) borate anion [ (C)₆F₅)₄B^－]And the like. These ionic compounds may be used alone or in combination of two or more. Particularly preferred is the bis (trifluoromethanesulfonyl) imide anion [ (CF)₃SO₂)₂N^－]Bis (fluorosulfonyl) imide anion [ (FSO)₂)₂N^－]Tetrakis (pentafluorophenyl) borate anion [ (C)₆F₅)₄B^－]。

From the viewpoint of the stability with time of the antistatic performance of the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition, an ionic compound which is solid at room temperature is preferable.

The content of the antistatic agent is, for example, 0.01 to 20 parts by mass, preferably 0.1 to 10 parts by mass, and more preferably 1 to 7 parts by mass, per 100 parts by mass of the resin (a).

The pressure-sensitive adhesive composition may contain 1 or 2 or more of additives such as a solvent, a crosslinking catalyst, a tackifier, a plasticizer, an agent, a pigment, a rust inhibitor, an inorganic filler, and light-scattering fine particles.

< adhesive layer >

The pressure-sensitive adhesive layer of the present invention can be formed, for example, by dissolving or dispersing the pressure-sensitive adhesive composition in a solvent to prepare a solvent-containing pressure-sensitive adhesive composition, applying the composition to the surface of a substrate, and drying the composition.

The substrate is preferably a plastic film, and specifically, a release film subjected to a release treatment is exemplified. Examples of the release film include: a film obtained by subjecting one surface of a film containing a resin such as polyethylene terephthalate, polybutylene terephthalate, polycarbonate, or polyarylate to a mold release treatment such as a silicone treatment.

The pressure-sensitive adhesive layer of the present invention is preferably a pressure-sensitive adhesive layer satisfying the following formula (3), and more preferably a pressure-sensitive adhesive layer also satisfying the formula (4).

A(405)≥0.5 (3)

A(405)/A(440)≥5 (4)

A larger value of A (405) indicates a higher absorption at a wavelength of 405 nm. If the value of a (405) is less than 0.5, absorption at a wavelength of 405nm is low, and deterioration of a member (for example, a display device such as an organic EL element, a liquid crystal retardation film, or the like) which is easily deteriorated by light in the vicinity of 400nm is likely to occur. The value of a (405) is preferably 0.6 or more, more preferably 0.8 or more, still more preferably 1.0 or more, and particularly preferably 2.0 or more. There is no specific upper limit, and it is usually 10 or less.

The value of A (405)/A (440) represents the magnitude of absorption at a wavelength of 405nm relative to the magnitude of absorption at a wavelength of 440nm, and a larger value indicates more specific absorption in a wavelength region around 405 nm. The value of a (405)/a (440) is preferably 10 or more, more preferably 30 or more, further preferably 75 or more, and particularly preferably 100 or more.

The thickness of the adhesive layer of the present invention is usually 0.1 to 30 μm, preferably 3 to 30 μm, and more preferably 5 to 25 μm.

< optical layered body >

The adhesive composition of the present invention and the adhesive layer formed from the adhesive composition can be used for, for example, bonding an optical film.

An optical film with an adhesive layer (optical laminate) in which an optical film is laminated on at least one side of the adhesive layer of the present invention is also included in the present invention.

The optical laminate of the present invention can be formed by dissolving or dispersing the pressure-sensitive adhesive composition in a solvent to prepare a solvent-containing pressure-sensitive adhesive composition, applying the solvent-containing pressure-sensitive adhesive composition to the surface of an optical film, and drying the applied solvent-containing pressure-sensitive adhesive composition. Alternatively, the pressure-sensitive adhesive layer may be formed on the release film in the same manner, and the pressure-sensitive adhesive layer may be laminated (transferred) on the surface of the optical film.

Fig. 1 to 5 show examples of the layer structures of the pressure-sensitive adhesive layer of the present invention and the optical laminate of the present invention.

The pressure-sensitive adhesive layer 1 shown in fig. 1 is a state in which a release film 2 is bonded to the pressure-sensitive adhesive layer surface 1 in order to temporarily protect the pressure-sensitive adhesive layer surface.

The optical laminate 10A shown in fig. 2 is an optical laminate including a protective film 8, an adhesive layer 7, a polarizing film 9, an adhesive layer 7, a protective film 3, an adhesive layer 1, and a release film 2. The

protective films

3 and 8 may have a phase difference. The optical laminate 10B shown in fig. 3 is an optical laminate including a protective film 8, an adhesive layer 7, a polarizing film 9, an adhesive layer 7, an adhesive layer 1, and a release film 2. The optical laminate 10C shown in fig. 4 and the optical laminate 10D shown in fig. 5 are optical laminates including a protective film 8, an adhesive layer 7, a polarizing film 9, an adhesive layer 7, a protective film 3, an adhesive layer 1, an optical film 40, an adhesive layer 7a, and a light-emitting element 30 (a liquid crystal element or an organic EL element).

The optical film 40 has optical functions of transmitting, reflecting, and absorbing light. The optical film 40 may be a single-layer film or a multilayer film. Examples of the optical film 40 include a polarizing film, a phase difference film, a brightness enhancement film, an antiglare film, an antireflection film, a diffusion film, a light-collecting film, and a window film, and preferably a polarizing film, a phase difference film, a window film, or a laminated film thereof.

The condensing film is used for the purpose of optical path control or the like, and may be a prism array sheet, a lens array sheet, a sheet provided with a dot matrix, or the like.

The brightness enhancement film is used for the purpose of improving the brightness of a liquid crystal display device to which a polarizing plate is applied. Specifically, there may be mentioned: a reflective polarization separation sheet designed to have a reflectance anisotropy by laminating a plurality of films having different refractive index anisotropies, an alignment film of a cholesteric liquid crystal polymer, a circularly polarized light separation sheet in which an alignment liquid crystal layer thereof is supported on a base film, and the like.

The window film is a front panel in a flexible display device such as a flexible display, and is generally disposed on the outermost surface of the display device. Examples of the window film include resin films containing polyimide resins. The window film may be, for example, a mixed film of an organic material and an inorganic material, such as a resin film containing polyimide and silica. The window film may have a hard coat layer on its surface for imparting functions such as surface hardness, stain resistance, and fingerprint resistance. Examples of the window film include films described in Japanese patent laid-open publication No. 2017-94488.

The polarizing film is a film having the following properties: the polarizing film is a film that absorbs linearly polarized light having a plane of vibration parallel to the absorption axis thereof and transmits linearly polarized light having a plane of vibration orthogonal to the absorption axis (parallel to the transmission axis), and for example, a film in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol resin film can be used.

Examples of the dichroic dye include iodine and a dichroic organic dye.

The saponification degree of the polyvinyl alcohol resin is usually 85 mol% to 100 mol%, and preferably 98 mol% or more. The polyvinyl alcohol resin may be modified, and may be, for example, polyvinyl formal, polyvinyl acetal, or the like, which is obtained by modifying an aldehyde. The polymerization degree of the polyvinyl alcohol resin is usually 1000 to 10000, preferably 1500 to 5000.

A film formed of a polyvinyl alcohol resin is generally used as a raw material film of a polarizing film. The polyvinyl alcohol resin can be formed into a film by a known method. The thickness of the raw material film is usually 1 to 150 μm, and preferably 10 μm or more in consideration of ease of stretching and the like.

The polarizing film is produced, for example, by subjecting a raw material film to uniaxial stretching, dyeing the film with a dichroic dye to adsorb the dichroic dye, treating the film with an aqueous boric acid solution, washing the film with water, and finally drying. The thickness of the polarizing film is usually 1 to 30 μm, and from the viewpoint of making a film of the optical laminate with an adhesive layer thinner, the thickness is preferably 20 μm or less, more preferably 15 μm or less, and particularly 10 μm or less.

The polarizing plate is preferably provided with a protective film on at least one surface of the polarizing film via an adhesive.

As the adhesive, a known adhesive can be used, and an aqueous adhesive or an active energy ray-curable adhesive can be used.

Examples of the aqueous adhesive include conventional aqueous adhesives (for example, adhesives containing an aqueous polyvinyl alcohol resin solution, aqueous two-component urethane emulsion adhesives, aldehyde compounds, epoxy compounds, melamine compounds, methylol compounds, isocyanate compounds, amine compounds, crosslinking agents such as polyvalent metal salts, and the like). Among them, an aqueous adhesive containing an aqueous solution of a polyvinyl alcohol resin can be suitably used. In the case of using the water-based adhesive, it is preferable to perform a drying step after the polarizing film and the protective film are bonded to each other in order to remove water contained in the water-based adhesive. After the drying step, a curing step of curing at a temperature of, for example, about 20 to 45 ℃ may be provided. The adhesive layer formed of the aqueous adhesive is usually 0.001 to 5 μm.

The active energy ray-curable adhesive is an adhesive which is cured by irradiation with an active energy ray such as an ultraviolet ray or an electron ray, and examples thereof include a curable composition containing a polymerizable compound and a photopolymerization initiator, a curable composition containing a photoreactive resin, a curable composition containing a binder resin and a photoreactive crosslinking agent, and the like, and an ultraviolet ray-curable adhesive is preferable.

Examples of the method for bonding the polarizing film and the protective film include: and a method of performing a surface activation treatment such as saponification, corona treatment, or plasma treatment on at least one of the surfaces to be bonded. When the protective films are laminated on both surfaces of the polarizing film, the adhesives used for laminating the resin films may be the same type of adhesive or different types of adhesives.

The protective film is preferably a film made of a transparent thermoplastic resin. Specifically, examples include polyolefin-based resins; a cellulose-based resin; a polyester resin; (meth) acrylic resins; or mixtures, copolymers, etc. thereof. When protective films are provided on both sides of the polarizing film, the protective films used may be films containing different thermoplastic resins or films containing the same thermoplastic resin.

When a protective film is laminated on at least one surface of the polarizing film, the protective film is preferably a protective film containing a polyolefin resin or a cellulose resin. By using these films, shrinkage of the polarizing film in a high-temperature environment can be effectively suppressed without impairing the optical characteristics of the polarizing film. The protective film may be an oxygen barrier layer.

A preferable structure of the polarizing plate is one in which a protective film is laminated on at least one surface of a polarizing film via an adhesive layer. When the protective film is laminated on only one surface of the polarizing film, it is more preferably laminated on the visible side. The protective film laminated on the visible side is preferably a protective film containing a triacetyl cellulose resin or a cycloolefin resin. The protective film may be an unstretched film or may be stretched in any direction to have a retardation. The surface of the protective film laminated on the visible side may be provided with a surface treatment layer such as a hard coat layer or an antiglare layer.

When the protective films are laminated on both sides of the polarizing film, the protective film on the panel side (the side opposite to the visible side) is preferably a protective film or a retardation film comprising a triacetyl cellulose resin, a cycloolefin resin, or an acrylic resin. The retardation film may be a zero retardation film described later.

The retardation film is an optical film exhibiting optical anisotropy, and examples thereof include: and stretched films obtained by stretching a polymer film containing polyvinyl alcohol, polycarbonate, polyester, polyarylate, polyimide, polyolefin, polycycloolefin, polystyrene, polysulfone, polyethersulfone, polyvinylidene fluoride/polymethyl methacrylate, acetyl cellulose, a saponified ethylene-vinyl acetate copolymer, polyvinyl chloride, or the like by a factor of about 1.01 to 6. Among the stretched films, a polymer film obtained by uniaxially or biaxially stretching an acetyl cellulose, polyester, polycarbonate film, or cycloolefin resin film is preferable. The retardation film may be one in which a liquid crystalline compound is applied to a substrate and aligned to exhibit optical anisotropy.

In the present specification, the retardation film includes a zero retardation film, and includes films such as a uniaxial retardation film, a low photoelastic coefficient retardation film, and a wide-angle retardation film.

Zero retardation film means that the front retardation R is_eRetardation R with respect to the thickness direction_thAll of them are-15 to 15nm and optically isotropic films. The zero retardation film may be a resin film containing a cellulose-based resin, a polyolefin-based resin (e.g., a chain polyolefin-based resin or a polycycloolefin-based resin), or a polyethylene terephthalate-based resin, and is preferably a cellulose-based resin or a polyolefin-based resin from the viewpoint of easy control of retardation value and easy availability. A zero retardation film may also be used as the protective film. Examples of the zero retardation film include: "Z-TAC" (trade name) sold by Fuji film corporation, "Zero TAC (registered trademark)" sold by Konica Minolta corporation, "ZF-14" (trade name) sold by Nippon Rieger Co., Ltd.

In the optical film of the present invention, the retardation film is preferably a retardation film in which a liquid crystalline compound is applied and aligned to exhibit optical anisotropy.

Examples of the film exhibiting optical anisotropy by application and alignment of a liquid crystalline compound include the following first to fifth embodiments.

The first mode is as follows: a retardation film in which the rod-like liquid crystal compound is oriented in a horizontal direction with respect to the supporting substrate,

The second mode is as follows: a retardation film in which the rod-like liquid crystal compound is aligned in a direction perpendicular to the supporting substrate,

A third mode: a retardation film in which the orientation direction of the rod-like liquid crystal compound changes in a spiral shape in a plane,

A fourth formula: a retardation film in which a discotic liquid crystal compound is oriented obliquely,

The fifth mode is: a biaxial retardation film in which a discotic liquid crystal compound is aligned in a direction perpendicular to a support base.

For example, the first, second, and fifth embodiments are suitable as optical films used in organic electroluminescent displays. Alternatively, a retardation film of these types may be laminated and used.

When the retardation film is a layer containing a polymer in an aligned state of a polymerizable liquid crystal compound (hereinafter, sometimes referred to as "optically anisotropic layer"), the retardation film preferably has reverse wavelength dispersibility. The reverse wavelength dispersibility is an optical property that a retardation value in a liquid crystal alignment plane at a short wavelength is smaller than that at a long wavelength, and it is preferable that the retardation film satisfies the following formulas (7) and (8). Re (λ) represents an in-plane phase difference value with respect to light having a wavelength λ nm.

Re(450)/Re(550)≤1 (7)

1≤Re(630)/Re(550) (8)

In the optical film of the present invention, when the retardation film is of the first aspect and has reverse wavelength dispersibility, coloration in black display in a display device is reduced, and therefore, it is preferable that 0.82. ltoreq. Re (450)/Re (550). ltoreq.0.93 is more preferable in the above formula (7). Furthermore, 120. ltoreq. Re (550). ltoreq.150 is preferred.

Examples of the polymerizable liquid crystal compound in the case where the retardation film is a film having an optically anisotropic layer include: examples of the polymerizable liquid crystal compounds include compounds having a polymerizable group among compounds described in "3.8.6 network (completely crosslinked type)" and "6.5.1 liquid crystal material b" which are available from "liquid crystal materials" published by the editorial committee for liquid crystal accessibility (12 years, 10 months, 30 days) "and" polymerizable nematic liquid crystal materials ", and polymerizable liquid crystal compounds described in japanese patent application laid-open nos. 2010-31223, 2010-270108, 2011-6360, 2011-207765, 2011-162678, 2016-81035, international publication nos. 2017/043438 and 2011-765.

Examples of a method for producing a retardation film from a polymer in an aligned state of a polymerizable liquid crystal compound include the method described in jp 2010-31223 a.

In the case of the second mode, the front phase difference Re (550) may be adjusted to a range of 0 to 10nm, preferably 0 to 5nm, and the phase difference R in the thickness direction_thIt is adjusted to a range of-10 to-300 nm, preferably-20 to-200 nm. Thickness-direction phase difference value R representing thickness-direction refractive index anisotropy_thThe phase difference value R can be measured by tilting the fast axis in the plane by 50 degrees as the tilt axis₅₀Phase difference value R from plane₀And (6) calculating. Namely, the phase difference value R in the thickness direction_thCan be calculated as follows: according to the in-plane phase difference value R₀A phase difference value R measured by tilting the optical axis by 50 degrees with the fast axis as the tilt axis₅₀Thickness d of retardation film, and average refractive index n of retardation film₀N is obtained by the following equations (10) to (12)_x、n_yAnd n_zThen, they are calculated by substituting them into the formula (9).

R_th＝[(n_x+n_y)/2－n_z]×d (9)

R₀＝(n_x－n_y)×d (10)

(n_x+n_y+n_z)/3＝n₀(12)

Here, the number of the first and second electrodes,

examples of the film exhibiting optical anisotropy by application and alignment of a liquid crystalline compound and the film exhibiting optical anisotropy by application of an inorganic layered compound include: a FILM called a temperature compensation type phase difference FILM, "NH FILM" (trade name: a FILM in which rod-like liquid crystal is obliquely oriented) sold by JX rijie energy corporation, "WV FILM" (trade name: a FILM in which discotic liquid crystal is obliquely oriented) sold by fuji FILM corporation, "FILM" (trade name: a FILM in which complete biaxial orientation) sold by sumitomo chemical corporation, "new VAC FILM" (trade name: a FILM in which biaxial orientation) sold by sumitomo chemical corporation, and the like.

The retardation film may be a multilayer film having two or more layers. Examples thereof include: a film obtained by laminating a protective film on one or both surfaces of a retardation film, or a film obtained by laminating two or more retardation films with an adhesive or a bonding agent interposed therebetween.

When the retardation film is a multilayer film, as a configuration of an optical laminate including the optical film of the present invention, as shown in fig. 4, there can be mentioned: the retardation film 110 is composed of a 1/4 wavelength retardation layer 50 which imparts a retardation of 1/4 wavelength parts to transmitted light and a 1/2 wavelength retardation layer 70 which imparts a retardation of 1/2 wavelength parts to transmitted light, which are laminated via an adhesive layer or an adhesive layer 60. As shown in fig. 5, there may be mentioned: the optical film comprises an optical film 40 in which an 1/4 wavelength retardation layer 50a and a positive C layer 80 are laminated via an adhesive layer or a pressure-sensitive adhesive layer 60.

The 1/4 wavelength retardation layer 50 that imparts a retardation of 1/4 wavelength parts and the 1/2 wavelength retardation layer 70 that imparts a retardation of 1/2 wavelength parts to transmitted light in fig. 4 may be the optical film of the first embodiment or the optical film of the fifth embodiment. In the case of the configuration of fig. 4, at least one of them is more preferably the fifth aspect.

In the case of the configuration of fig. 5, the 1/4-wavelength retardation layer 50a is preferably an optical film of the first embodiment, and more preferably satisfies the expressions (7) and (8).

The adhesive layer 7a in fig. 4 and 5 is a layer formed of an adhesive composition. The adhesive layer 7a may be formed using a known adhesive composition, or may be formed using the adhesive composition of the present invention.

< liquid Crystal display device >

The resin of the present invention, the adhesive composition containing the resin, and the optical laminate comprising the adhesive layer formed from the adhesive composition can be used in display devices (FPD: flat panel display) such as organic EL display devices and liquid crystal display devices by being laminated on display devices such as organic EL devices and liquid crystal devices.

Examples

The present invention will be described in further detail below with reference to examples and comparative examples. In examples and comparative examples, "%" and "part(s)" are "% by mass" and "part(s) by mass" unless otherwise specified.

Example 1: synthesis of light-selective absorbing Compound (1) having polymerizable group and merocyanine Structure

A 300mL four-necked flask equipped with a diemroth (Dimroth) condenser and a thermometer was placed under a nitrogen atmosphere, 10 parts of 2-hydroxyethyl acrylate, 8.1 parts of cyanoacetic acid, 1.1 parts of N, N-dimethyl-4-aminopyridine, 0.95 part of dibutylhydroxytoluene, and 50 parts of toluene were added, and the mixture was stirred with a magnetic stirrer. After cooling in an ice bath, it was confirmed that the internal temperature was 10 ℃, 12 parts of N, N-diisopropylcarbodiimide was added dropwise over 1 hour, and after completion of the addition, the temperature was maintained at 0 to 10 ℃ in the internal temperature for 2 hours. Thereafter, insoluble matter was removed by filtration under reduced pressure to obtain 70 parts of a filtrate containing a compound represented by UVA-M-02.

A300 mL four-necked flask equipped with a Dimerosal condenser and a thermometer was placed in a nitrogen atmosphere, and 20 parts of the compound represented by UVA-M-01 synthesized with reference to Japanese unexamined patent publication No. 2014-194508, 7.1 parts of acetic anhydride, 70 parts of a filtrate containing UVA-M-02, and 40 parts of acetonitrile were charged and stirred with a magnetic stirrer. The internal temperature is 25 DEG CTo the resulting mixture was added dropwise 9 parts of N, N-diisopropylethylamine over 1 hour. The resulting mixture was incubated at an internal temperature of 25 ℃ for 2 hours. To the resulting mixture was added 200g of ice water and stirred, and the precipitated crude product was removed by filtration under reduced pressure. The obtained crude product was recrystallized from isopropyl alcohol to obtain 10 parts of a compound represented by UVA-01. The obtained compound represented by UVA-01 was subjected to LC-MS and¹H-NMR was carried out for identification.

[M+H]⁺＝291.0

¹H－NMR(CDCl₃)δ：2.10(quin、2H)、3.02(m.5H)、3.66(t、2H)、4.41(s、4H)、5.53(d、1H)、5.84(d、1H)、6.14(dd、1H)、6.46(d、1H)、7.92(7.92、d)

< measurement of the extinction coefficient ε >

The obtained 2-butanone solution (61.2g/L) of the compound represented by UVA-01 was added to a 1cm quartz cuvette, which was set in a spectrophotometer UV-2450 (manufactured by Shimadzu corporation), and the absorbance was measured in 1nm steps in a wavelength range of 300 to 800nm by a two-beam method. And calculating the gram absorption coefficient at each wavelength according to the obtained absorbance value, the UVA-01 concentration in the solution and the optical path length of the quartz cuvette.

ε(λ)＝A(λ)/CL

[ in the formula,. epsilon. (. lamda.) represents the gram absorption coefficient (L/(g. cm)) of the resin (A) at a wavelength of. lamda.,. alpha.,. lambda.,. C represents the concentration (g/L)), and L represents the optical path length (cm) of the quartz cuvette. ]

The compound represented by UVA-01 obtained had an ε (405) of 49L/(g.cm) and ε (440) of 0L/(g.cm).

Example 2: synthesis of light-selective absorbing Compound (2) having polymerizable group and merocyanine Structure

After replacing the nitrogen atmosphere in a 2000mL four-necked flask equipped with a thermometer with a nitrogen atmosphere, 100 parts of 4-hydroxybutyl acrylate, 65 parts of cyanoacetic acid, 8.5 parts of 4-dimethylaminopyridine, 7.7 parts of 2, 6-di-tert-butyl-4-methylphenol, and 500 parts of acetonitrile were charged and cooled to 0 ℃ to 10 ℃ while stirring. While maintaining this temperature, 96 parts of N, N' -diisopropylcarbodiimide was added dropwise over 2 hours. After completion of the dropwise addition, the resulting mixture was filtered to obtain 725 parts of an acetonitrile solution containing the compound represented by UVA-M-03.

A3000 mL four-necked flask equipped with a thermometer was charged with a nitrogen atmosphere, 266 parts of a compound represented by UVA-M-01, 71 parts of acetic anhydride, and 837 parts of acetonitrile were charged, and 725 parts of an acetonitrile solution containing the compound represented by UVA-M-03 was charged. While the resulting mixture was stirred, 90 parts of diisopropylethylamine was added dropwise to the resulting mixture over 2 hours. 200g of silica gel was put into the obtained mixture, followed by filtration, and 1000 parts of toluene and 1000 parts of water were mixed with the obtained filtrate to separate the mixture into liquid, thereby obtaining an organic layer. The obtained organic layer was further subjected to liquid separation washing with 1000 parts of water. The above-mentioned liquid separation washing was repeated 3 times, and the obtained organic layer was concentrated. The concentrated residue was mixed with 730 parts of dimethylformamide, the resulting solution was cooled, 2000 parts of water were added, and the precipitated crystal was collected by filtration. The obtained crystals were recrystallized from isopropanol and dried to obtain 86 parts of a compound represented by UVA-02.

1H－NMR(CDCl₃)δ：1.75－1.82(m、4H)、2.04－2.11(m、2H)、2.95－3.02(t、2H)、3.02(s、3H)、3.60－3.65(t、2H)、4.16－4.22(m、4H)、5.48－5.52(d、1H)、5.78－5.81(d、1H)、6.06－6.13(dd、1H)、6.36－6.41(d、1H)、7.88－7.92(d、1H)

< measurement of the extinction coefficient ε >

A2-butanone solution (60.2g/L) of a compound represented by UVA-02 was placed in a 1cm quartz cuvette, which was set in a spectrophotometer UV-2450 (manufactured by Shimadzu corporation), and the absorbance was measured in 1nm steps in a wavelength range of 300 to 800nm by a two-beam method. The compound represented by UVA-02 obtained had an ε (405) of 45L/(g.cm) and ε (440) of 0L/(g.cm).

[ example 3 ]: preparation of resin (A-1) having a merocyanine Structure

A reaction vessel equipped with a condenser, a nitrogen inlet tube, a thermometer and a stirrer was charged with a mixed solution of 86.4 parts of ethyl acetate, 60 parts of butyl acrylate, 1.9 parts of 2-hydroxyethyl acrylate and 1.9 parts of a compound represented by UVA-01 as a solvent, and the internal temperature was increased to 60 ℃ while the atmosphere in the apparatus was replaced with nitrogen gas to remove oxygen. To the obtained mixture, a solution of 0.4 parts of azobisisobutyronitrile (polymerization initiator) dissolved in 10 parts of ethyl acetate was added in total. The resulting mixture was maintained at 60 ℃ for 1 hour, ethyl acetate was continuously added to the reaction vessel at an addition rate of 17.3 parts/hour while maintaining the internal temperature of 50 to 70 ℃, the addition of ethyl acetate was stopped when the concentration of the acrylic resin reached 35%, and the internal temperature was maintained at 50 to 70 ℃ from the start of the addition of ethyl acetate to the elapse of 12 hours. Ethyl acetate was added to the resultant mixture to adjust the concentration of the resin (A-1) having a merocyanine structure to 20%, thereby preparing an ethyl acetate solution of the resin (A-1) having a merocyanine structure. The weight average molecular weight Mw of the obtained resin (A-1) having a merocyanine structure was 50 ten thousand in terms of polystyrene by GPC, and Mw/Mn was 7.5. This was used as resin (A-1). The glass transition temperature based on DSC was-48.4 ℃.

< measurement of the extinction coefficient ε >

The obtained ethyl acetate solution (0.006g/L) of the resin (A-1) was placed in a 1cm quartz cuvette, which was set in a spectrophotometer UV-2450 (manufactured by Shimadzu corporation), and the absorbance was measured in 1nm steps in a wavelength range of 300 to 800nm by a two-beam method. The gram absorption coefficient at each wavelength was calculated from the obtained absorbance value, the concentration of the resin (A) in the solution, and the optical path length of the quartz cuvette. The results are shown in Table 1.

ε(λ)＝A(λ)/CL

[ in the formula,. epsilon. (. lamda.) represents the gram absorption coefficient L/(g.cm) of the resin (A) at a wavelength of. lamda.,. C represents the concentration g/L, and L represents the optical path length cm of the quartz cuvette. ]

[ example 4 ]: preparation of resin (A-2) having a merocyanine Structure

A reaction vessel equipped with a condenser, a nitrogen inlet tube, a thermometer and a stirrer was charged with a mixed solution of 78 parts of ethyl acetate, 18 parts of butyl acrylate, 0.66 part of 2-hydroxyethyl acrylate and 3.3 parts of a compound represented by UVA-01 as a solvent, and the internal temperature was increased to 65 ℃ while replacing the air in the apparatus with nitrogen gas to remove oxygen. To the obtained mixture, a solution of 0.13 parts of azobisisobutyronitrile (polymerization initiator) dissolved in 10 parts of ethyl acetate was added in total. After the obtained mixture was kept at 65 ℃ for 6 hours, a solution prepared by dissolving 0.026 part of azobisisobutyronitrile (polymerization initiator) in 10 parts of ethyl acetate was added to the whole amount of the obtained mixture, and the mixture was kept at 65 ℃ for 4 hours. Next, to the obtained mixture was added all of a solution prepared by dissolving 0.0012 part of 4-methoxyphenol (polymerization inhibitor) in 5 parts of ethyl acetate. Ethyl acetate was added to the resulting mixture to adjust the concentration of the resin (a-2) having a merocyanine structure to 20%, thereby preparing an ethyl acetate solution of the resin (a-2) having a merocyanine structure. The weight average molecular weight Mw of the obtained resin (A-2) having a merocyanine structure was 17 ten thousand in terms of polystyrene by GPC, and Mw/Mn was 5.9. The glass transition temperature based on DSC was-47.5 ℃.

The gram absorption coefficient of the resin (A-2) was determined in the same manner as above. The results are shown in Table 1.

[ example 5 ]: preparation of resin (A-3) having a merocyanine Structure

A reaction vessel equipped with a condenser, a nitrogen inlet tube, a thermometer and a stirrer was charged with a mixed solution of 86.4 parts of ethyl acetate, 60 parts of butyl acrylate, 1.9 parts of 2-hydroxyethyl acrylate and 1.9 parts of a compound represented by UVA-02 as a solvent, and the internal temperature was increased to 60 ℃ while the atmosphere in the apparatus was replaced with nitrogen gas to remove oxygen. To the obtained mixture, a solution of 0.4 parts of azobisisobutyronitrile (polymerization initiator) dissolved in 10 parts of ethyl acetate was added in total. The resulting mixture was maintained at 60 ℃ for 1 hour, ethyl acetate was continuously added to the reaction vessel at an addition rate of 17.3 parts/hour while maintaining the internal temperature of 50 to 70 ℃, the addition of ethyl acetate was stopped when the concentration of the acrylic resin reached 35%, and the internal temperature was maintained at 50 to 70 ℃ from the start of the addition of ethyl acetate to the elapse of 12 hours. To the resulting mixture was added ethyl acetate and adjustment was made so that the concentration of the resin (a-3) having a merocyanine structure reached 20%, to prepare an ethyl acetate solution of the resin (a-3) having a merocyanine structure. The weight average molecular weight Mw of the obtained resin (A-3) having a merocyanine structure was 50 ten thousand in terms of polystyrene by GPC, and Mw/Mn was 6.3. This was used as resin (A-3). The glass transition temperature based on DSC was-52.3 ℃.

The gram absorption coefficient of the resin (A-3) was determined in the same manner as above. The results are shown in Table 1.

[ polymerization example 1 ]: preparation of acrylic resin (A-4)

A reaction vessel equipped with a condenser, a nitrogen inlet tube, a thermometer and a stirrer was charged with a mixed solution of 86.4 parts of ethyl acetate, 61.9 parts of butyl acrylate and 1.9 parts of 2-hydroxyethyl acrylate as a solvent, and the internal temperature was increased to 60 ℃ while the atmosphere in the apparatus was replaced with nitrogen gas to exclude oxygen. Then, a solution prepared by dissolving 0.4 part of azobisisobutyronitrile (polymerization initiator) in 10 parts of ethyl acetate was added in total. The resulting mixture was kept at 60 ℃ for 1 hour, ethyl acetate was continuously added to the reaction vessel at an addition rate of 17.3 parts/hour while keeping the internal temperature at 50 to 70 ℃, the addition of ethyl acetate was stopped when the concentration of the acrylic resin reached 35%, and the temperature was maintained at that temperature until 12 hours elapsed from the start of the addition of ethyl acetate. Finally, ethyl acetate was added to adjust the concentration of the acrylic resin to 20%, to prepare an ethyl acetate solution of the acrylic resin. The weight average molecular weight Mw of the obtained acrylic resin was 60 ten thousand in terms of polystyrene based on GPC, and Mw/Mn was 7.0. This was used as resin (A-4). The glass transition temperature based on DSC was-52.9 ℃.

The gram absorption coefficient of the resin (A-4) was determined in the same manner as above. The results are shown in Table 1.

[ TABLE 1]

In table 1, the symbols located in the column of the monomer composition each refer to the following monomer.

BA: acrylic acid butyl ester

HEA: 2-Hydroxyethyl acrylate

UVA-01: light selective absorbing compound having polymerizable group and merocyanine structure synthesized in synthesis example 1

UVA-02: light selective absorbing compound having polymerizable group and merocyanine structure synthesized in synthesis example 2

< preparation of adhesive composition and adhesive layer >

(a) Preparation of adhesive composition

[ example 6 ]: preparation of adhesive composition (1)

In the ethyl acetate solution (resin concentration: 20%) of the resin (A-1) having a merocyanine structure obtained above, 0.5 parts of a crosslinking agent (CORONATE L, 75% of solid content: manufactured by Tosoh) and 0.5 parts of a silane compound (KBM-403, manufactured by shin-Etsu chemical industries) were mixed with 100 parts of the solid content of the solution, and 2-butanone was added so that the solid content concentration became 14%, thereby obtaining a pressure-sensitive adhesive composition (1). The amount of the crosslinking agent (CORONATE L) is the mass part based on the active ingredient.

[ example 7 ]: preparation of adhesive composition (2)

In the ethyl acetate solution (resin concentration: 20%) of the resin (A-2) having a merocyanine structure obtained above, 0.5 parts of a crosslinking agent (CORONATE L, 75% of solid content: manufactured by Tosoh) and 0.5 parts of a silane compound (KBM-403, manufactured by shin-Etsu chemical industries) were mixed with 100 parts of the solid content of the solution, and 2-butanone was added so that the solid content concentration became 14%, thereby obtaining a pressure-sensitive adhesive composition (2). The amount of the crosslinking agent (CORONATE L) is the mass part based on the active ingredient.

[ example 8 ]: preparation of adhesive composition (3)

In the ethyl acetate solution (resin concentration: 20%) of the resin (A-3) having a merocyanine structure obtained above, 0.5 parts of a crosslinking agent (CORONATE L, 75% of solid content: manufactured by Tosoh) and 0.5 parts of a silane compound (KBM-403, manufactured by shin-Etsu chemical industries) were mixed with 100 parts of the solid content of the solution, and 2-butanone was added so that the solid content concentration became 14%, thereby obtaining an adhesive composition (3). The amount of the crosslinking agent (CORONATE L) is the mass part based on the active ingredient.

Comparative example 1: preparation of adhesive composition (4)

In an ethyl acetate solution (resin concentration: 20%) of an acrylic resin (A-4), 0.5 parts of a crosslinking agent (CORONATE L, 75% of solid content: manufactured by Tosoh), 0.5 parts of a silane compound (KBM-403, manufactured by shin-Etsu chemical Co., Ltd.), and 1 part of a light-absorbing compound (ultraviolet light absorber; BONASORB UA-3911, manufactured by eastern chemical Co., Ltd.) were mixed with 100 parts of the solid content of the solution, and 2-butanone was added so that the solid content concentration became 14%, thereby obtaining an adhesive composition (4). The amount of the crosslinking agent (CORONATE L) is the mass part based on the active ingredient.

Further, a 2-butanone solution (56.0g/L) of BONASORB UA-3911 was placed in a 1cm quartz cuvette, which was set in a spectrophotometer UV-2450 (manufactured by Shimadzu corporation), and the absorbance was measured in 1nm steps in a wavelength range of 300 to 800nm by a two-beam method. The obtained UVA-02 had an ε (405) of 93L/(g. cm) and ε (440) of 1.3L/(g. cm).

Preparation example 1: preparation of adhesive composition (5)

0.5 parts of a crosslinking agent (CORONATE L, manufactured by Tosoh Co., Ltd., solid content 75%) and 0.5 part of a silane compound (manufactured by shin Etsu chemical Co., Ltd.: KBM-403) were mixed with an ethyl acetate solution (resin concentration: 20%) of the acrylic resin (A-4), and 2-butanone was added so that the solid content concentration became 14% to obtain an adhesive composition (5). The amount of the crosslinking agent (CORONATE L) is the mass part based on the active ingredient.

(b) Production of adhesive layer

Each of the pressure-sensitive adhesive compositions prepared in (a) above was applied to a release-treated surface of a polyethylene terephthalate film (SP-PLR 382050 manufactured by Lintec, hereinafter simply referred to as a "spacer") subjected to release treatment using an applicator (applicator) so that the thickness of the dried pressure-sensitive adhesive layer became 20 μm, and dried at 100 ℃ for 1 minute to prepare a pressure-sensitive adhesive layer. The pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition obtained in example 4 was regarded as the pressure-sensitive adhesive layer (1), the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition obtained in example 5 was regarded as the pressure-sensitive adhesive layer (2), the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition obtained in example 6 was regarded as the pressure-sensitive adhesive layer (3), the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition obtained in comparative example 1 was regarded as the pressure-sensitive adhesive layer (4), and the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition obtained in preparation example 1 was regarded as the pressure-sensitive adhesive layer (5).

< measurement of Absorbance of pressure-sensitive adhesive layer >

In order to measure the absorbance of the obtained pressure-sensitive adhesive layers (1) to (4), the pressure-sensitive adhesive layers (1) to (4) were bonded to glass, and after the spacers were peeled off, a cycloolefin polymer (COP) film (ZF-14 manufactured by gironiu corporation) was bonded to the pressure-sensitive adhesive layers to prepare a laminate for pressure-sensitive adhesive layer evaluation. The pressure-sensitive adhesive layer-evaluating laminate thus prepared was set in a spectrophotometer UV-2450 (manufactured by Shimadzu corporation), and the absorbance was measured in a wavelength range of 300 to 800nm by a two-beam method at 1nm step. The absorbance of the prepared adhesive layer is shown in table 2. The absorbance of the glass at the wavelength of 405nm and the absorbance of the COP film at the wavelength of 440nm were both 0.

< production of optical layered body >

(i) Production of polarizing film (polarizing plate)

A polyvinyl alcohol FILM having an average polymerization degree of about 2400 and a saponification degree of 99.9 mol% and a thickness of 30 μm ("kuraraypaval FILM VF-PE # 3000", manufactured by kuraray corporation) was immersed in pure water at 37 ℃ and then immersed in an aqueous solution containing iodine and potassium iodide at 30 ℃ (iodine/potassium iodide/water (weight ratio): 0.04/1.5/100). Thereafter, it was immersed in an aqueous solution containing potassium iodide and boric acid at 56.5 ℃ (potassium iodide/boric acid/water (weight ratio) ═ 12/3.6/100). Then, the film was washed with pure water at 10 ℃ and dried at 85 ℃ to obtain a polarizing film a having a thickness of about 12 μm in which iodine was adsorbed and oriented on polyvinyl alcohol. The stretching was mainly performed in the steps of iodine dyeing and boric acid treatment, and the total stretching magnification was 5.3 times.

(ii) Fabrication of polarizing plates

(ii) a transparent protective film ("25 KCHCN-TC", manufactured by letterpress printing) obtained by applying a hard coat layer of 7 μm to a cellulose triacetate film of 25 μm thickness was laminated on one surface of the polarizing film obtained in (i) via an adhesive agent comprising an aqueous solution of a polyvinyl alcohol resin. On the surface opposite to the transparent protective film, a cycloolefin resin film ("ZF 14-023", manufactured by japan rayleigh corporation) having a thickness of 23 μm was laminated via an adhesive agent composed of an aqueous solution of a polyvinyl alcohol resin, to prepare an optical film a (polarizing plate, thickness 67 μm).

(iii) Preparation of composition for forming photo-alignment film

A photo-alignment film-forming composition was obtained by mixing 5 parts of a photo-alignment material having the following structure and 95 parts of cyclopentanone as components, and stirring the resulting mixture at 80 ℃ for 1 hour. The photo-alignment material described below is synthesized by the method described in jp 2013-33248 a.

(iv) Preparation of composition A containing polymerizable liquid Crystal Compound

A composition containing a polymerizable liquid crystal compound was obtained by mixing 12 parts of a polymerizable liquid crystal compound A having the following structure, 0.12 part of a polyacrylate compound (leveling agent, BYK-361N manufactured by BYK-Chemie Co., Ltd.), 0.72 part of a polymerization initiator (IRGACURE 369 manufactured by Ciba specialty Chemicals Co., Ltd.), and 100 parts of cyclopentanone.

The polymerizable liquid crystal compound a is synthesized by the method described in japanese patent application laid-open No. 2010-31223. The maximum absorption wavelength λ max (LC) of the polymerizable liquid crystal compound A was 350 nm.

(v) Production of optically anisotropic layer

A cycloolefin polymer film (ZF-14, manufactured by Ration corporation, Japan) was treated 1 time with a corona treatment device (AGF-B10, manufactured by Chunshi electric Co., Ltd.) under conditions of an output of 0.3kW and a treatment speed of 3 m/min. (iv) the photo-alignment film-forming composition obtained in (iii) was bar-coated on the corona-treated surface, dried at 80 ℃ for 1 minute, and irradiated at 100mJ/cm using a polarized UV irradiation apparatus (SPOT CURE SP-7; manufactured by NIFI TAIL MOTOR CO., LTD.)²The cumulative amount of light of (a) is subjected to polarized UV exposure. The film thickness of the obtained alignment film was measured by an ellipsometer, and the result was 100 nm.

Next, a coating liquid containing the composition A containing the polymerizable liquid crystal compound obtained in (iv) was applied onto the alignment film BY using a bar coater, dried at 120 ℃ for 1 minute, and then irradiated with ultraviolet light (cumulative light quantity at a wavelength of 313nm under nitrogen atmosphere: 500 mJ/cm) from the side coated with the composition containing the polymerizable liquid crystal compound BY using a high-pressure mercury lamp (Unicure VB-15201 BY-A, manufactured BY NIFI TAIL MOTOR Co., Ltd.)²) Thereby, an optical film including the optically anisotropic layer 1 was formed. The thickness of the obtained optically anisotropic layer 1 was measured by a laser microscope, and was 2 μm.

Example 9: production of optical laminate (1)

The adhesive layer (1) was bonded to the cycloolefin resin film surface of the polarizing plate produced in the above (ii), and the spacer was peeled off. Further, the surface of the pressure-sensitive adhesive layer (1) from which the spacer was peeled and the opposite surface to the COP surface of the optically anisotropic layer produced in (V) were bonded to each other, and the COP was peeled. The pressure-sensitive adhesive layer (5) with a spacer was bonded to the surface of the optically anisotropic layer from which the COP had been peeled off, thereby obtaining an optical laminate (1).

Example 10: production of optical laminate (2)

An optical laminate (2) was obtained in the same manner as in example 7, except that the pressure-sensitive adhesive layer (1) was replaced with the pressure-sensitive adhesive layer (2).

Example 11: production of optical laminate (3)

An optical laminate (3) was obtained in the same manner as in example 7, except that the pressure-sensitive adhesive layer (1) was replaced with the pressure-sensitive adhesive layer (3).

Comparative example 2: production of optical laminate (4)

An optical laminate (4) was obtained in the same manner as in example 7, except that the pressure-sensitive adhesive layer (1) was replaced with the pressure-sensitive adhesive layer (4).

< evaluation of bleeding resistance of adhesive layer >

The obtained optical laminate (1) was cut into a size of 30mm × 30mm, and the spacer laminated on the pressure-sensitive adhesive layer (3) was peeled off and bonded to alkali-free glass [ trade name "EAGLE XG" manufactured by corning corporation ]. The obtained optical laminate with glass was put into an oven at 85 ℃ for 120 hours, and then the presence or absence of crystal deposition of the compound in the plane was confirmed using a microscope. The evaluation results are shown in Table 2.

The bleeding resistance of the pressure-sensitive adhesive layer was evaluated in the same manner as above, except that the optical laminate (1) was replaced with the optical laminate (2). The evaluation results are shown in Table 2.

The bleeding resistance of the pressure-sensitive adhesive layer was evaluated in the same manner as above, except that the optical laminate (1) was replaced with the optical laminate (3). The evaluation results are shown in Table 2.

The bleeding resistance of the pressure-sensitive adhesive layer was evaluated in the same manner as above, except that the optical laminate (1) was replaced with the optical laminate (4). The evaluation results are shown in Table 2.

< confirmation of transferability to optically Anisotropic layer >

The optical laminate (1) thus obtained was cut into a size of 30mm × 30mm, and the resulting laminate was put into an oven at a temperature of 85 ℃ for 120 hours with the spacers on the adhesive layer (5) as they were. Thereafter, the separator was peeled from the pressure-sensitive adhesive layer (5), and FTIR measurement was performed on the surface of the pressure-sensitive adhesive layer (5) by the ATR method. Peaks 1550-1560 cm in the light selective absorbing compound having a polymerizable group and a merocyanine structure^－1Then, it is judged whether or not the light selective absorbing compound having a polymerizable group and a merocyanine structure is transferred from the pressure-sensitive adhesive layer (1) to the pressure-sensitive adhesive layer (5). The results are shown in Table 2.

The transferability to the optically anisotropic layer was confirmed in the same manner as above, except that the optical laminate (1) was replaced with the optical laminate (2). The evaluation results are shown in Table 2.

The transferability to the optically anisotropic layer was confirmed in the same manner as above, except that the optical laminate (1) was replaced with the optical laminate (3). The evaluation results are shown in Table 2.

The transferability to the optically anisotropic layer was confirmed in the same manner as above, except that the optical laminate (1) was replaced with the optical laminate (4). The evaluation results are shown in Table 2.

< confirmation of the influence of the adhesive layer on the retardation change of the optically anisotropic layer >

The obtained optical laminate (1) was cut into a size of 30mm × 30mm, and the spacer laminated on the pressure-sensitive adhesive layer (5) was peeled off and bonded to alkali-free glass [ trade name "EAGLE XG" manufactured by corning corporation ]. The retardation value at a wavelength of 450nm of the obtained optical laminate with glass was measured by a birefringence measurement device (KOBRA-WR; manufactured by Oji scientific Co., Ltd.). Thereafter, the optical laminate with glass was put into an oven at 85 ℃ for 120 hours, taken out, left to stand at 23 ℃ for 24 hours in a 50% atmosphere, and the phase difference value at a wavelength of 450nm was measured again. A phase difference change value is obtained from the change amount of the phase difference value before and after the durability. The change values are shown in Table 2.

The influence of the change in retardation by the pressure-sensitive adhesive layer on the optically anisotropic layer was confirmed in the same manner as above except that the optical laminate (1) was replaced with the optical laminate (2). The phase difference change value before and after endurance was obtained. The change values are shown in Table 2.

The influence of the change in retardation by the pressure-sensitive adhesive layer on the optically anisotropic layer was confirmed in the same manner as above, except that the optical laminate (1) was replaced with the optical laminate (3). The phase difference change value before and after endurance was obtained. The change values are shown in Table 2.

The influence of the change in retardation by the pressure-sensitive adhesive layer on the optically anisotropic layer was confirmed in the same manner as above except that the optical laminate (1) was replaced with the optical laminate (4). The phase difference change value before and after endurance was obtained. The change values are shown in Table 2.

[ TABLE 2]

The adhesive composition of the present invention has good bleeding resistance without causing compound precipitation even after being subjected to a heat resistance test at 85 ℃ for 120 hours. In addition, an optical laminate including an adhesive layer formed from the adhesive composition of the present invention does not cause transfer of the light-absorbing compound from the adhesive layer to the optically anisotropic layer, and can suppress deterioration of the retardation film and the like. In addition, an optical laminate including a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition of the present invention has a small change in retardation even after a durability test (heat resistance test at 85 ℃ for 120 hours), and has good display characteristics.

Industrial applicability

The resin of the present invention, the adhesive composition containing the resin, and the optical laminate containing the adhesive layer formed from the adhesive composition are suitably used for a liquid crystal panel and a liquid crystal display device.

Description of the symbols

1 adhesive layer

2 Release film

10A, 10B, 10C, 10D optical laminate

3.8 protective film

4 optical film

7 adhesive layer

7a adhesive layer

9 polarizing film

30 light emitting element

40 optical film

50. 50a 1/4 wavelength phase difference layer

60 adhesive layer or adhesive layer

701/2 wavelength phase difference layer

80 positive C layer

100 polarizing plate

Claims

1. A resin A which contains a structural unit having a merocyanine structure and has a glass transition temperature of 40 ℃ or lower.

2. The resin according to claim 1, wherein the resin A is a resin satisfying the following formula (1),

ε(405)≥0.02 (1)

in the formula (1), ε (405) represents the gram absorption coefficient of the resin at a wavelength of 405nm, and the unit of the gram absorption coefficient is L/(g · cm).

3. The resin according to claim 1 or 2, wherein,

the resin A is a resin satisfying the following formula (2),

ε(405)/ε(440)≥5 (2)

in the formula (2), ε (405) represents the gram absorption coefficient of the resin at a wavelength of 405nm, and ε (440) represents the gram absorption coefficient of the resin at a wavelength of 440 nm.

4. The resin according to any one of claims 1 to 3, wherein,

the resin a is a resin containing a structural unit having a merocyanine structure in a side chain.

5. The resin according to claim 4, wherein,

the structural unit having a merocyanine structure in a side chain is a structural unit derived from a compound represented by formula (I),

in the formula, R¹、R²、R³、R⁴And R⁵Each independently represents a hydrogen atom, an optionally substituted aliphatic hydrocarbon group having 1 to 25 carbon atoms, an optionally substituted aromatic hydrocarbon group having 6 to 15 carbon atoms, a heterocyclic group or an ethylenically unsaturated group, -CH contained in the aliphatic hydrocarbon group or the aromatic hydrocarbon group₂-is optionally substituted by-NR^1A－、－SO₂-, -CO-, -O-or-S-,

R⁶and R⁷Each independently represents a hydrogen atom, an alkyl group having 1 to 25 carbon atoms, an electron-withdrawing group or an ethylenically unsaturated group,

R^1Arepresents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms,

R¹and R²Optionally joined to each other to form a ring structure, R²And R³Optionally joined to each other to form a ring structure, R²And R⁴Optionally joined to each other to form a ring structure, R³And R⁶Optionally joined to each other to form a ring structure, R⁵And R⁷Optionally joined to each other to form a ring structure, R⁶And R⁷Optionally joined to each other to form a ring structure,

R¹～R⁷any 1 of which is an ethylenically unsaturated group.

6. The resin according to claim 5, wherein,

the compound shown in the formula (I) is a compound shown in a formula (II),

in the formula (II), R¹¹、R¹²、R¹³、R¹⁴And R¹⁵Each independently represents a hydrogen atom, an optionally substituted aliphatic hydrocarbon group having 1 to 25 carbon atoms, an optionally substituted aromatic hydrocarbon group having 6 to 15 carbon atoms or a heterocyclic group, or-CH contained in the aliphatic hydrocarbon group or the aromatic hydrocarbon group₂-is optionally substituted by-NR^11A－、－SO₂-, -CO-, -O-or-S-,

R¹⁶and R¹⁷Each independently represents a hydrogen atom, an alkyl group having 1 to 25 carbon atoms, an electron-withdrawing group or an ethylenically unsaturated group,

R^11Arepresents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms,

R¹²and R¹³Optionally joined to each other to form a ring structure, R¹²And R¹⁴Optionally joined to each other to form a ring structure,

R¹⁶or R¹⁷Any 1 of which is an ethylenically unsaturated group.

7. The resin according to any one of claims 1 to 6,

the resin A is a resin further having at least 1 structural unit selected from the structural units described in the following group A,

In the formula, R^a1Represents twoA monovalent hydrocarbon group selected from the group consisting of,

R^b1and R^b2Each independently represents a hydrogen atom or a hydrocarbon group,

R^c1and R^c2Each independently represents a divalent hydrocarbon group.

8. The resin according to claim 7, wherein,

the content of at least 1 structural unit selected from the structural units described in group a is 50% by mass or more with respect to the total structural units of the resin a.

9. An adhesive composition comprising the resin of any one of claims 1-8.

10. The adhesive composition of claim 9, further comprising a crosslinker B.

11. An adhesive layer formed from the adhesive composition of claim 9 or 10.

12. The adhesive layer according to claim 11, which satisfies the following formula (3),

A(405)≥0.5 (3)

in the formula (3), A (405) represents the absorbance at a wavelength of 405 nm.

13. The adhesive layer according to claim 12, which further satisfies the following formula (4),

A(405)/A(440)≥5 (4)

in the formula (4), A (405) represents the absorbance at a wavelength of 405nm, and A (440) represents the absorbance at a wavelength of 440 nm.

14. An optical laminate comprising the adhesive layer according to any one of claims 11 to 13 and an optical film laminated on at least one side of the adhesive layer.

15. The optical stack of claim 14,

the optical film is a polarizing plate.

16. An image display device comprising the optical stack of claim 15.

17. A compound represented by the formula (II),

R^11Arepresents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms,

wherein R is¹⁶Or R¹⁷Any 1 of which is an ethylenically unsaturated group.