CN110799611A

CN110799611A - Adhesive sheet and film with adhesive layer

Info

Publication number: CN110799611A
Application number: CN201880042798.2A
Authority: CN
Inventors: 阪上智惠; 小桥亚依; 浅津悠司
Original assignee: Sumitomo Chemical Co Ltd
Current assignee: Sumitomo Chemical Co Ltd
Priority date: 2017-06-27
Filing date: 2018-06-21
Publication date: 2020-02-14
Also published as: JP2019007001A; TW201906963A; KR20200024780A; KR20230113849A; JP7182913B2; WO2019004043A1

Abstract

The invention provides an adhesive sheet which exhibits high absorption selectivity for ultraviolet rays and visible light having a short wavelength of around 405nm, and thus has a good function of inhibiting deterioration of a retardation film or an organic EL light-emitting element caused by ultraviolet rays. The adhesive sheet of the present invention is an adhesive layer formed from an adhesive composition containing at least a (meth) acrylic resin and a light selective absorbing compound, and satisfies the following formulas (1) and (2). A (350) ≥ 0.5(1) A (405) ≥ 0.5(2) [ in formula (1), A (350) represents absorbance at wavelength 350 nm. In the formula (2), A (405) represents absorbance at a wavelength of 405nm ].

Description

Adhesive sheet and film with adhesive layer

Technical Field

The present invention relates to an adhesive sheet and an adhesive layer-attached film using the same.

Background

Display devices (FPD: flat panel display) such as organic EL display devices and liquid crystal display devices use various members such as display elements such as organic EL elements and liquid crystal cells, and optical films such as polarizing plates. Since organic EL compounds, liquid crystal compounds, and the like used in these members are organic substances, deterioration by ultraviolet rays (UV) is likely to be a problem. In order to solve such a problem, for example, patent document 1 describes a polarizing plate in which an ultraviolet absorber having excellent ultraviolet absorption performance in a wavelength region of 370nm or less is added to a protective film of the polarizing plate.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2006-308936

Disclosure of Invention

Problems to be solved by the invention

In recent years, thinning of display devices has been advanced, and development of a liquid crystal retardation film obtained by aligning and photocuring a polymerizable liquid crystal compound has been advanced. It has been clearly recognized that these liquid crystal retardation films and organic EL light-emitting devices tend to be deteriorated not only by ultraviolet light but also by visible light having a short wavelength of about 400 nm. However, the polarizing plate described in patent document 1 has excellent ultraviolet absorption performance in a wavelength region of 370nm or less, but has low absorption performance for visible light in the vicinity of 400nm, and thus deterioration suppression of a liquid crystal retardation film and an organic EL light emitting element may be insufficient. Further, in recent display devices, further excellent display characteristics are required.

The invention provides an adhesive sheet which exhibits high absorption selectivity for ultraviolet rays and short-wavelength visible light having a wavelength of about 405nm, and has a good function of inhibiting deterioration of a retardation film or an organic EL light-emitting element caused by ultraviolet rays or short-wavelength visible light.

Means for solving the problems

The present invention includes the following inventions.

[1] An adhesive sheet comprising an adhesive composition containing a (meth) acrylic resin (A) and a light selective absorbing compound, and satisfying the following formulas (1) and (2).

A(350)≥0.5 (1)

A(405)≥0.5 (2)

[ in the formula (1), A (350) represents the absorbance at a wavelength of 350 nm.

In the formula (2), A (405) represents the absorbance at a wavelength of 405 nm. ]

[2] The adhesive sheet according to [1], which further satisfies the following formula (3).

A(440)≤0.1 (3)

[ in formula (3), A (440) represents the absorbance at a wavelength of 440 nm. ]

[3] The adhesive sheet according to [1], 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. ]

[4] The adhesive sheet according to any one of [1] to [3], wherein the light selective absorption compound includes a compound that selectively absorbs light having a wavelength of 350nm and a compound that selectively absorbs light having a wavelength of 405 nm.

[5] The adhesive sheet according to [4], wherein the compound that selectively absorbs light having a wavelength of 405nm is a compound satisfying the formula (5).

ε(405)≥20 (5)

[ in formula (5),. epsilon. (. 405) represents the gram absorption coefficient of the compound at a wavelength of 405 nm. The unit of the gram absorption coefficient is L/(g.cm). Angle (c)

[6] The adhesive sheet according to [5], wherein the compound that selectively absorbs light having a wavelength of 405nm is a compound satisfying the formula (6).

ε(405)/ε(440)≥20 (6)

[ in the formula (6),. epsilon. (405) represents the gram absorption coefficient of the compound at a wavelength of 405nm, and. epsilon. (440) represents the gram absorption coefficient at a wavelength of 440 nm. ]

[7] The adhesive sheet according to any one of [4] to [6], wherein the compound that selectively absorbs light having a wavelength of 405nm is a compound having a merocyanine structure in the molecule.

[8] The adhesive sheet according to any one of [1] to [7], wherein the adhesive composition further comprises a crosslinking agent.

[9] The adhesive sheet according to [8], wherein the content of the crosslinking agent (B) is 0.01 to 15 parts by mass per 100 parts by mass of the (meth) acrylic resin (A).

[10] The adhesive sheet according to any one of [1] to [9], wherein the content of the light selective absorbing compound is 0.01 to 20 parts by mass per 100 parts by mass of the (meth) acrylic resin (A).

[11] An optical film having the pressure-sensitive adhesive layer according to any one of [1] to [10], wherein the optical film is laminated on at least one surface of the pressure-sensitive adhesive sheet.

[12] The polarizing plate with an adhesive layer according to [11], wherein the optical film is a polarizing plate.

[13] A display device comprising the optical film with an adhesive according to any one of [11] or [12 ].

Effects of the invention

The pressure-sensitive adhesive sheet of the present invention exhibits high absorption selectivity for ultraviolet light and visible light having a short wavelength of around 405nm, and thus has a good function of suppressing deterioration of a retardation film or an organic EL light-emitting device due to ultraviolet light. The adhesive sheet of the present invention exhibits high absorption selectivity for visible light having a short wavelength of around 405nm even after a weather resistance test, and can keep the deterioration due to ultraviolet light or visible light having a short wavelength. When the adhesive sheet of the present invention is used for a display device, good display characteristics and durability can be provided.

Drawings

Fig. 1 shows an example of the layer structure of the adhesive sheet of the present invention.

Fig. 2 shows an example of the layer structure of an optical laminate including the pressure-sensitive adhesive sheet of the present invention.

Fig. 3 shows an example of the layer structure of an optical laminate including the pressure-sensitive adhesive sheet of the present invention.

Fig. 4 shows an example of the layer structure of an optical laminate including the pressure-sensitive adhesive sheet of the present invention.

Detailed Description

The adhesive sheet of the present invention is formed from an adhesive composition containing a (meth) acrylic resin (a) and a light selective absorbing compound, and satisfies the following formulae (1) and (2).

A(350)≥0.5 (1)

A(405)≥0.5 (2)

A (350) is higher at a wavelength of 350 nm. When the value of a (350) is less than 0.5, absorption at a wavelength of 350nm is low, and the effect of suppressing deterioration of a display device such as a retardation film or an organic EL element under ultraviolet light is small. The value of a (350) is preferably 0.5 or more, more preferably 0.8 or more, and particularly preferably 1.0 or more.

The larger the value of A (405), the higher the absorption at a wavelength of 405 nm. When the value of a (405) is less than 0.5, absorption at a wavelength of 405nm is low, and the effect of suppressing deterioration of a display device such as a retardation film or an organic EL element under ultraviolet light or short-wavelength visible light is small. The value of a (405) is preferably 0.6 or more, more preferably 0.8 or more, and particularly preferably 1.0 or more. The upper limit is not particularly limited, but is usually 10 or less.

The adhesive sheet of the present invention preferably further satisfies any one of the following formulae (3) and (4), and more preferably satisfies both the following formulae (3) and (4).

A(440)≤0.1 (3)

A(405)/A(440)≥5 (4)

The smaller the value of A (440), the lower the absorption at a wavelength of 440nm, and the larger the value of A (440) is than 0.1, the favorable color expression of the display device tends to be impaired. In addition, since light emission of the display device is inhibited, luminance is also reduced. The value of a (440) is preferably 0.05 or less, more preferably 0.04 or less, and particularly preferably 0.03. The lower limit is not particularly limited, and is usually 0.00001 or more.

The value of a (405)/a (440) represents the magnitude of absorption at a wavelength of 405nm with respect to the magnitude of absorption at a wavelength of 440nm, and the larger the value, the more specific the adhesive sheet of the present invention has absorption in a wavelength region near 405 nm. The value of A (405)/A (440) is preferably 10 or more, more preferably 30 or more, and particularly preferably 60 or more.

The adhesive layer of the present invention is formed from an adhesive composition containing at least a (meth) acrylic resin and a light selective absorbing compound.

The adhesive composition preferably further comprises a crosslinking agent.

The light selective absorbing compound is not particularly limited as long as it selectively absorbs light having a wavelength of 350nm or light having a wavelength of 405 nm. The light selective absorbing compound preferably comprises a compound that selectively absorbs light having a wavelength of 350nm and a compound that selectively absorbs light having a wavelength of 405 nm.

Examples of the compound that selectively absorbs light having a wavelength of 350nm (hereinafter, may be referred to as a light selective absorbing compound (a)) include an ultraviolet absorber. The ultraviolet absorber is not particularly limited, and examples thereof include organic ultraviolet absorbers such as oxybenzone-based ultraviolet absorbers, benzotriazole-based ultraviolet absorbers, salicylate-based ultraviolet absorbers, benzophenone-based ultraviolet absorbers, cyanoacrylate-based ultraviolet absorbers, and triazine-based ultraviolet absorbers. More specifically, examples thereof include 5-chloro-2- (3, 5-di-sec-butyl-2-hydroxyphenyl) -2H-benzotriazole, (2-2H-benzotriazol-2-yl) -6- (linear and side chain dodecyl) -4-methylphenol, 2-hydroxy-4-benzyloxybenzophenone, 2, 4-benzyloxybenzophenone and the like. These organic ultraviolet absorbers may be used in 1 kind or 2 or more kinds in combination.

Examples of the ultraviolet absorber include "Kemisorb 102" manufactured by Chemipro corporation, "adekasab LA 46" and "adekasab LAF 70" manufactured by ADEKA corporation, "Tinuvin 109", "Tinuvin 171", "Tinuvin 234", "Tinuvin 326", "Tinuvin 327", "Tinuvin 328", "Tinuvin 928", "Tinuvin 400", "Tinuvin 460", "Tinuvin 405" and "Tinuvin 477". Examples of the benzotriazole-based ultraviolet absorbers include "Adekastab LA 31" and "Adekastab LA 36" manufactured by ADEKA corporation, "Sumisorb 200", "Sumisorb 250", "Sumisorb 300", "Sumisorb 340" and "Sumisorb 350" manufactured by Chemitex corporation, "Kemisorb 74", "Kemisorb 79" and "Kemisorb 279" manufactured by BASF corporation, "TINUVIN 99-2", "TINUVIN 900" and "TINUVIN 928".

The ultraviolet absorber may be an inorganic ultraviolet absorber. Examples of the inorganic ultraviolet absorber include titanium oxide, zinc oxide, indium oxide, tin oxide, talc, kaolin, calcium carbonate, titanium oxide-based composite oxide, zinc oxide-based composite oxide, ITO (tin-doped indium oxide), ATO (antimony-doped tin oxide), and the like. Examples of the titanium oxide-based composite oxide include zinc oxide doped with silica or alumina. These inorganic ultraviolet absorbers may be used in 1 kind, or 2 or more kinds in combination. In addition, the organic ultraviolet absorber and the inorganic ultraviolet absorber may be used in combination.

The compound that selectively absorbs light having a wavelength of 405nm (hereinafter, sometimes referred to as a light selective absorbing compound (B)) is preferably a compound that satisfies the following formula (5), and more preferably a compound that also satisfies the following formula (6).

ε(405)≥20 (5)

ε(405)/ε(440)≥20 (6)

The gram absorbance coefficient was measured by the method described in examples.

The larger the value of ε (405), the more easily the compound absorbs light having a wavelength of 405nm, and the more suppressed the deterioration of the retardation film under ultraviolet light or visible light having a short wavelength. If the value of ∈ (405) is less than 20L/(g · cm), the function of suppressing deterioration of the retardation film or the organic EL light-emitting element due to ultraviolet light or short-wavelength visible light tends to be difficult to exhibit without increasing the content of the light selective absorbing compound (B) in the adhesive composition. When the content of the light selective absorbing compound (B) is increased, the light selective absorbing compound (B) may bleed out or be unevenly dispersed, and the light absorbing function may be insufficient. The value of ε (405) is preferably 20L/(g cm) or more, more preferably 30L/(g cm) or more, still more preferably 40L/(g cm) or more, and usually 500L/(g cm) or less.

The larger the value of epsilon (405)/epsilon (440), the more the compound can absorb light near 405nm without inhibiting the color expression of the display device and suppress the light degradation of the display device such as a retardation film and an organic EL element. The value of ε (405)/ε (440) is preferably 20 or more, more preferably 40 or more, still more preferably 70 or more, and particularly preferably 80 or more.

The compound that selectively absorbs light having a wavelength of 405nm is preferably a compound containing a merocyanine structure in the molecule. The compound containing a merocyanine structure in the molecule is a compound containing a partial structure represented by- (N-C) -in the molecule, and examples thereof include merocyanine compounds, cyanine compounds, indole compounds, benzotriazole compounds, and the like, preferably merocyanine compounds, cyanine compounds, and benzotriazole compounds, and more preferably a compound represented by formula (I).

[ in the formula, R¹And R⁵Each independently represents a hydrogen atom, an alkyl group having 1 to 25 carbon atoms which may have a substituent, an aralkyl group having 7 to 15 carbon atoms which may have a substituent, an aryl group having 6 to 15 carbon atoms, a heterocyclic group, or-CH contained in the alkyl group or the aralkyl group₂Can be represented by-NR^1A－、－CO－、－SO₂-, -O-or-S-substitution.

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

R²、R³And R⁴Each independently represents a hydrogen atom, an optionally substituted alkyl group having 1 to 6 carbon atoms, an optionally substituted aromatic hydrocarbon group or an optionally substituted aromatic heterocyclic group, -CH contained in the alkyl group₂Can be represented by-NR^1B－、－CO－、－SO₂-, -O-or-S-substitution.

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

R⁶And R⁷Each independently represents a hydrogen atom, an alkyl group having 1 to 25 carbon atoms or an electron-withdrawing group, or R⁶And R⁷Are connected to form a ring structure.

R¹And R²Can be connected to each other to form a ring structure, R²And R³Can be connected to each other to form a ring structure, R²And R⁴Can be connected to each other to form a ring structure, R³And R⁶May be joined to form a ring structure.]

As by R¹And R⁵Examples of the alkyl group having 1 to 25 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, a 2-cyanopropyl group, an n-butyl group, a tert-butyl group, a sec-butyl group, an n-pentyl group, an n-hexyl group, a 1-methylbutyl group, a,3-methylbutyl, n-octyl, n-decyl, 2-hexyl-octyl and the like.

As by R¹And R⁵The substituent that the alkyl group having 1 to 25 carbon atoms may have is exemplified by the groups described in the following group A.

Group A includes nitro, hydroxy, carboxyl, sulfo, cyano, amino, halogen atom, alkoxy of 1 to 6 carbon atoms, alkylsilyl of 1 to 12 carbon atoms, alkylcarbonyl of 2 to 8 carbon atoms, and ＊ -R^a1－(O－R^a2)_t1－R^a3(R^a1And R^a2Each independently represents an alkanediyl group having 1 to 6 carbon atoms, R^a3Represents an alkyl group having 1 to 6 carbon atoms, and s1 represents an integer of 1 to 3. ) The group represented, and the like.

Examples of the alkylsilyl group having 1 to 12 carbon atoms include monoalkylsilyl groups such as methylsilyl group, ethylsilyl group, and propylsilyl group; dialkylsilyl groups such as dimethylsilyl group, diethylsilyl group and methylethylsilyl group; trialkylsilyl groups such as trimethylsilyl, triethylsilyl and tripropylsilyl groups.

Examples of the alkylcarbonyl group having 2 to 8 carbon atoms include a methylcarbonyl group, an ethylcarbonyl group and the like.

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

As by R¹And R⁵Examples of the aralkyl group having 7 to 15 carbon atoms include benzyl group and phenylethyl group. as-CH contained in aralkyl groups₂-by-SO₂Examples of the-or-COO-substituted group include 2-phenylacetate ethyl group and the like.

As by R¹And R⁵The aralkyl group having 7 to 15 carbon atoms may have a substituent, and examples thereof include those described in the above group A.

As by R¹And R⁵Examples of the aryl group having 6 to 15 carbon atoms include phenyl, naphthyl and anthracenyl.

As by R¹And R⁵The substituent which the aryl group having 6 to 15 carbon atoms may have is exemplified by the groups described in the above group A.

As by R¹And R⁵Examples of the heterocyclic group having 6 to 15 carbon atoms include aromatic heterocyclic groups having 3 to 9 carbon atoms such as a pyridyl group, a pyrrolidinyl group, a quinolyl group, a thienyl group, an imidazolyl group, an oxazolyl group, a pyrrolyl group, a thiazolyl group and a furyl group.

As by R^1AAnd R^1BExamples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a tert-butyl group, a sec-butyl group, an n-pentyl group, and an n-hexyl group.

As by R²、R³And R⁴Examples of the alkyl group having 1 to 6 carbon atoms represented by the formula R^1BThe alkyl group having 1 to 6 carbon atoms is the same as the alkyl group.

As by R²、R³And R⁴Examples of the substituent which may be contained in the alkyl group having 1 to 6 carbon atoms include those described in the above group A.

As by R²、R³And R⁴The aromatic hydrocarbon group includes aryl groups having 6 to 15 carbon atoms such as phenyl, naphthyl, and anthracenyl; aralkyl groups having 7 to 15 carbon atoms such as benzyl group and phenylethyl group.

As by R²、R³And R⁴The aromatic hydrocarbon group may have a substituent, and examples thereof include those described in the above group A.

As by R²、R³And R⁴Examples of the aromatic heterocyclic group include aromatic heterocyclic groups having 3 to 9 carbon atoms such as pyridyl, pyrrolidinyl, quinolyl, thienyl, imidazolyl, oxazolyl, pyrrolyl, thiazolyl and furyl groups.

As by R²、R³And R⁴The substituents which the aromatic heterocyclic ring may have include those described in the above group A.

As by R⁶And R⁷Examples of the alkyl group having 1 to 25 carbon atoms includeIs reacted with R¹And R⁵The alkyl group having 1 to 25 carbon atoms is the same as the alkyl group.

As by R⁶And R⁷Examples of the substituent which may be contained in the alkyl group having 1 to 25 carbon atoms include those described in the above group A.

As by R⁶And R⁷Examples of the alkyl group having 1 to 25 carbon atoms represented by the formula R¹And R⁵The alkyl group having 1 to 25 carbon atoms is the same as the alkyl group.

As by 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, and a group represented by the formula (I-1).

*-X¹-R¹¹(I-1)

[ in the formula, R¹¹Represents a hydrogen atom or an alkyl group having 1 to 25 carbon atoms, and at least 1 of methylene groups contained in the alkyl group may be replaced with an oxygen atom.

X¹represents-CO-, -COO-, -OCO-, -CS-, -CSO-, -CSS-, -NR-¹²CO-or CONR¹³－。

R¹²And R¹³Each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a phenyl group.]

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

R⁶And R⁷Can be connected to each other to form a ring structure consisting of R⁶And R⁷Examples of the ring structure to be formed include a meldrum's acid structure, a barbituric acid structure, and a dimedone structure.

As by R¹¹Having 1 to 25 carbon atomsAlkyl, may be exemplified by the group R¹And R⁵The alkyl groups shown are the same alkyl groups.

As R²And R³The ring structures formed by bonding with each other are those containing R²Examples of the nitrogen-containing ring structure of the bonded nitrogen atom include a4 to 14-membered nitrogen-containing heterocycle. R²And R³The ring structure formed by the mutual connection may be a single ring or multiple rings. 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.

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 a nitrogen-containing heterocycle having 4 to 14 rings (preferably 4 to 8 rings). R¹And R²The ring structure formed by the mutual connection may be a single ring or multiple rings. Specifically, R may be mentioned²And R³The ring structures are connected to form the same ring structure.

As R²And R⁴Examples of the ring structure formed by bonding to each other include a nitrogen-containing ring structure having 4 to 14 members, preferably a nitrogen-containing ring structure having 5 to 9 members. R²And R⁴The ring structures formed by bonding to each other may be monocyclic or polycyclic. These rings may have a substituent, and examples of such a ring structure include the structure represented by the formula R²And R³Examples of the ring structure to be formed include the same ring structures.

As R³And R⁶The ring structures formed by the mutual connection are R³－C＝C－C＝C－R⁶The ring structure forming the backbone of the ring. Examples thereof include phenyl groups.

As R²And R³The compound represented by the formula (I) which is linked to each other to form a ring structure includes a compound represented by the formula (I-A) wherein R is²And R⁴The compound represented by the formula (I) which is linked to each other to form a ring structure includes the compounds represented by the formula (I)The compound represented by I-B), and the like.

[ formula (I-A) or formula (I-B) wherein R¹、R³、R⁴、R⁵、R⁶And R⁷Each means the same as described above.

Ring W¹And a ring W²Each independently represents a nitrogen-containing ring.]

Ring W¹And a ring W²Represents a nitrogen-containing ring containing a nitrogen atom as a constituent unit of the ring. Ring W¹And a ring W²Each of which may be independently monocyclic or polycyclic, and may contain a hetero atom other than nitrogen as a constituent unit of the ring. Ring W¹And a ring W²Rings each independently of the other 5-to 9-membered ring are preferred.

The compound represented by the formula (I-A) is preferably a compound represented by the formula (I-A-1).

[ in the formula (I-A), R¹、R⁴、R⁵、R⁶And R⁷Each means the same as described above.

A¹represents-CH₂-, -O-, -S-or-NR^1D－。

R¹⁴And R¹⁵Each independently represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms.

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

The compound represented by the formula (I-B) is preferably a compound represented by the formula (I-B-1) or a compound represented by the formula (I-B-2).

[ in the formula (I-B-1), R¹、R⁶And R⁷Each means the same as described above.

R¹⁶Each independently represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or an aryl group.]

[ in the formula (I-B-2), R³、R⁵、R⁶And R⁷Each means the same as described above.

R³⁰Represents a hydrogen atom, a cyano group, a nitro group, a halogen atom, a mercapto group, an amino group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, an acyl group having 2 to 13 carbon atoms, an acyloxy group having 2 to 13 carbon atoms, or an alkoxycarbonyl group having 2 to 13 carbon atoms.

R³¹Represents an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, a mercapto group, an alkylthio group having 1 to 12 carbon atoms, an amino group which may have a substituent or a heterocyclic group.]

As by R³⁰Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

As by R³⁰Represented by R³⁰Examples of the acyl group having 2 to 13 carbon atoms include acetyl, propionyl, and butyryl.

As by R³⁰Examples of the acyloxy group having 2 to 13 carbon atoms include a methylcarbonyloxy group, an ethylcarbonyloxy group, a propylcarbonyloxy group, and a butylcarbonyloxy group.

As by R³⁰Examples of the alkoxycarbonyl group having 2 to 13 carbon atoms include a methoxycarbonyl group, an ethoxycarbonyl group, a propoxycarbonyl group, a butoxycarbonyl group and the like.

As by R³⁰The aromatic hydrocarbon group having 6 to 18 carbon atoms includes aryl groups having 6 to 18 carbon atoms such as phenyl, naphthyl and biphenyl; aralkyl groups having 7 to 18 carbon atoms such as benzyl group and phenylethyl group.

As by R³⁰Examples of the alkyl group having 1 to 12 carbon atoms represented by the formula R¹⁴The alkyl group is the same as the alkyl group having 1 to 12 carbon atoms.

As by R³⁰Examples of the alkyl group having 1 to 12 carbon atoms include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, and a pentyloxy group.

R³⁰Preferably an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an amino group or a mercapto group.

As by R³¹Examples of the alkyl group having 1 to 12 carbon atoms represented by the formula R¹⁴The alkyl group is the same as the alkyl group having 1 to 12 carbon atoms.

As by R³¹The alkoxy group having 1 to 12 carbon atoms is represented by R³⁰Alkoxy groups having 1 to 12 carbon atoms and the like.

As by R³¹The alkylthio group having 1 to 12 carbon atoms includes a methylthio group, an ethylthio group, a propylthio group, a butylthio group, a pentylthio group, a hexylthio group, and the like.

As by R³¹Examples of the optionally substituted amino group include an amino group; an amino group substituted with an alkyl group having 1 to 8 carbon atoms, such as an N-methylamino group or an N-ethylamino group; an amino group substituted with an alkyl group having 2 carbon atoms of 1 to 8, such as an N, N-dimethylamino group, an N, N-diethylamino group, or an N, N-methylethylamino group; and the like.

As by R³¹Examples of the heterocyclic ring include nitrogen-containing heterocyclic groups having 4 to 9 carbon atoms such as pyrrolidinyl, piperidinyl and morpholinyl groups.

As R³And R⁶Are connected to each other to form a ring structure, and R²And R⁴The compound represented by the formula (I) which forms a ring structure by bonding to each other includes compounds represented by the formula (I-C).

[ in the formula (I-C), R¹、R⁶And R⁷The same meanings as described above are indicated.

R²¹、R²²Each independently represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or a hydroxyl group.

X²And X³Each independently represents-CH₂-or-N (R)²⁵)＝。

R²⁵Represents a hydrogen atom, an alkyl group having 1 to 25 carbon atoms, or an aromatic hydrocarbon group which may have a substituent.]

As by R²⁵Examples of the alkyl group having 1 to 25 carbon atoms represented by the formula R¹The alkyl group having 1 to 25 carbon atoms is the same as the alkyl group.

As by R²⁵Examples of the aromatic hydrocarbon group include aryl groups such as phenyl and naphthyl: aralkyl groups such as benzyl and phenylethyl: biphenyl, and the like, preferably an aromatic hydrocarbon group having 6 to 20 carbon atoms. As by R²⁵Examples of the substituent which may be contained in the aromatic hydrocarbon group include a hydroxyl group.

R³And R⁶Preferably each independently is an electron-withdrawing group.

As R¹And R²Are connected to each other to form a ring structure, and R³And R⁶The compound represented by the formula (I) which is bonded to each other to form a ring structure includes compounds represented by the formula (I-D).

[ formula (I-D) wherein R⁴、R⁵、R⁷The same meanings as described above are indicated.

R²⁵、R²⁶、R²⁷And R²⁸Each independently represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms which may have a substituent, a hydroxyl group, or an aralkyl group.]

As by R²⁵、R²⁶、R²⁷And R²⁸Examples of the alkyl group having 1 to 12 carbon atoms represented by the formula R^1AAnd R^1BC1E C12 alkyl is the same alkyl. As by R²⁵、R²⁶、R²⁷And R²⁸The substituent that the alkyl group having 1 to 12 carbon atoms may have is a hydroxyl group.

As by R²⁵、R²⁶、R²⁷And R²⁸Examples of the aralkyl group include aralkyl groups having 7 to 15 carbon atoms such as a benzyl group and a phenylethyl group.

As R⁶And R⁷Examples of the compound (I) which is linked to each other to form a ring structure include compounds represented by the formula (I-E).

[ in the formula (I-E), R¹、R³、R⁴、R⁵Each means the same as described above.

Ring W³Represents a cyclic compound.]

Ring W³The ring may be a 5-to 9-membered ring, and may contain a heteroatom such as a nitrogen atom, an oxygen atom or a sulfur atom as a constituent unit of the ring.

The compound represented by the formula (I-E) is preferably a compound represented by the formula (IE-1).

[ in the formula (I-C-1), R¹、R²、R³And R⁵Each means the same as described above.

R¹⁷、R¹⁸、R¹⁹、R^qEach independently represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms which may have a substituent, an aralkyl group, an aryl group, or-CH contained in the alkyl group or the aralkyl group₂The radical-NR may be^1D-, -C (═ O) -, -C (═ S) -, -O-, -S-substitution, R¹⁷And R¹⁸Can be connected to each other to form a ring structure, R¹⁸And R¹⁹Can be connected to form a ring structure,R¹⁹and R^qMay be joined to form a ring structure. m, p and q each independently represent an integer of 0 to 3.]

The compound represented by the formula (I) includes the following compounds.

The total content of the light selective absorbing compounds is usually 0.01 to 20 parts by mass, preferably 0.05 to 15 parts by mass, more preferably 0.1 to 10 parts by mass, and still more preferably 0.1 to 5 parts by mass, based on 100 parts by mass of the (meth) acrylic resin.

The mass ratio of the light selective absorbing compound (A) to the light selective absorbing compound (B) (light selective absorbing compound (A)/light selective absorbing compound (B)) is usually 0.05 to 20, preferably 0.1 to 10.

(meth) acrylic resin (A) >, and a process for producing the same

The (meth) acrylic resin (a) is preferably a polymer containing a constituent unit derived from a (meth) acrylate ester as a main component (preferably containing 50 mass% or more). The structural unit derived from a (meth) acrylate ester may contain one or more structural units derived from a monomer other than a (meth) acrylate ester (for example, a structural unit derived from a monomer having a polar functional group). In the present specification, the term "(meth)" used in the case of (meth) acrylic acid ester refers to (meth) acrylic acid, and the term "meth" refers to (meth) acrylic acid ester or the like.

Examples of the (meth) acrylate include (meth) acrylates represented by the following formula (I).

[ in the formula (I), R₁Represents a hydrogen atom or a methyl group, R₂Represents an alkyl group having 1 to 14 carbon atoms or an aralkyl group having 7 to 20 carbon atoms, and the hydrogen atom of the alkyl group or the aralkyl group may be substituted with an alkoxy group having 1 to 10 carbon atoms.]

In the formula (I), R²Preferably an alkyl group having 1 to 14 carbon atoms, and more preferably an alkyl group having 1 to 8 carbon atoms.

Examples of the (meth) acrylate represented by the formula (I) 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, t-butyl (meth) acrylate, isoprene (i- ペンチル) meth (acrylate), isohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate, isostearyl (meth) acrylate, and isoprene (i- アミル) meth (acrylate);

alicyclic skeleton-containing alkyl esters 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 -ethoxycyclohexyl acrylate;

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

Further, there may be mentioned a substituted alkyl (meth) acrylate in which a substituent is introduced into the alkyl group of the alkyl (meth) acrylate. The substituent of the alkyl (meth) acrylate having a substituent is a group which substitutes for a hydrogen atom of an alkyl group, and specific examples thereof include a phenyl group, an alkoxy group, and a phenoxy group. Specific examples of the alkyl (meth) acrylate having 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 different (meth) acrylates may be used.

The (meth) acrylic resin (a) preferably contains a constituent unit derived from an alkyl acrylate (a1) having a homopolymer glass transition temperature Tg of less than 0 ℃ and a constituent unit derived from an alkyl acrylate (a2) having a homopolymer Tg of 0 ℃ or higher. From the viewpoint of improving the high-temperature durability of the pressure-sensitive adhesive layer, it is advantageous to contain a constituent unit derived from an alkyl acrylate (a1) and a constituent unit derived from an alkyl acrylate (a 2). 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 acrylate (a1) include alkyl acrylates having an alkyl group of about 2 to 12 carbon atoms such as ethyl acrylate, n-and iso-propyl acrylate, n-and iso-butyl acrylate, n-pentyl acrylate, n-and iso-hexyl acrylate, n-heptyl acrylate, n-and iso-octyl acrylate, 2-ethylhexyl acrylate, n-and iso-nonyl acrylate, n-and iso-decyl acrylate, and n-dodecyl acrylate.

The alkyl acrylate (a1) may be used in a single amount of 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 viewpoints of the follow-up property and the reworkability (リワーク property) when the adhesive sheet of the present invention is laminated on an optical film.

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

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

The structural unit derived from the (meth) acrylate represented by the formula (I) is preferably 50% by mass or more, more preferably 60 to 95% by mass, and further preferably 65 to 95% by mass or more of the total structural units contained in the (meth) acrylic resin.

The structural unit derived from a monomer other than a (meth) acrylate is preferably a structural unit derived from a monomer having a polar functional group, and more preferably a structural unit derived from a (meth) acrylate having a polar functional group. Examples of the polar functional group include a hydroxyl group, a carboxyl group, a substituted or unsubstituted amino group, a heterocyclic group such as an epoxy group, and the like.

Examples of the 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, hydroxy-decyl (meth) acrylate, hydroxy-dodecyl (meth), Hydroxyl group-containing monomers such as 11-hydroxydodecyl (meth) acrylate, 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;

carboxyl group-containing monomers such as (meth) acrylic acid, carboxyalkyl (meth) acrylate (e.g., carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate), maleic acid, maleic anhydride, fumaric acid, and crotonic acid;

monomers having a heterocyclic group such as acryloylmorpholine, vinylcaprolactam, N-vinyl-2-pyrrolidone, vinylpyridine, tetrahydrofurfuryl (meth) acrylate, caprolactone-modified tetrahydrofurfuryl acrylate, 3, 4-epoxycyclohexylmethyl (meth) acrylate, glycidyl (meth) acrylate, and 2, 5-dihydrofuran;

monomers having a substituted or unsubstituted amino group such as aminoethyl (meth) acrylate, N-dimethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, and the like.

Among them, from the viewpoint of reactivity between the (meth) acrylate polymer and the crosslinking agent, the monomer having a hydroxyl group and the monomer having a carboxyl group are preferable, and the monomer having a hydroxyl group and the monomer having a carboxyl group are more preferable.

As the monomer having a hydroxyl group, 2-hydroxyethyl acrylate, 3-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 5-hydroxypentyl acrylate, and 6-hydroxyhexyl acrylate are preferable. In particular, by using 2-hydroxyethyl acrylate, 4-hydroxybutyl acrylate and 5-hydroxypentyl acrylate, good durability can be obtained.

As the monomer having a carboxyl group, acrylic acid is preferably used.

From the viewpoint of preventing the increase in the peeling force of the release film that can be laminated on the outer surface of the adhesive sheet, it is preferable that the (meth) acrylic resin (a) contains substantially no structural unit derived from a monomer having an amino group. The term "substantially not included" as used herein means 0.1 parts by mass or less per 100 parts by mass of all the constituent units constituting the (meth) acrylic resin (a).

The content of the structural unit derived from the monomer having a polar functional group 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 the total structural units of the (meth) acrylic resin (a).

The content of the structural unit derived from the aromatic group-containing monomer is preferably 20 parts by mass or less, more preferably 4 parts by mass or more and 20 parts by mass or less, and further preferably 4 parts by mass or more and 16 parts by mass or less, based on 100 parts by mass of the total structural units of the (meth) acrylic resin (a).

Examples of the structural unit derived from a monomer other than the (meth) acrylate ester include a structural unit derived from a styrene monomer, a structural unit derived from a vinyl monomer, a structural unit derived from a monomer having a plurality of (meth) acryloyl groups in the molecule, and a structural unit derived from a (meth) acrylamide monomer.

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 ethylenes such as vinylpyridine, vinylpyrrolidone and vinylcarbazole; conjugated dienes such as butadiene, isoprene and chloroprene; and unsaturated nitriles such as acrylonitrile and methacrylonitrile.

Examples of the monomer having a plurality of (meth) acryloyl groups in a molecule include monomers having 2 (meth) acryloyl groups in a molecule, such as 1, 4-butanediol di (meth) acrylate, 1, 6-hexanediol di (meth) acrylate, 1, 9-nonanediol di (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, and tripropylene glycol di (meth) acrylate; a monomer having 3 (meth) acryloyl groups in the molecule, such as trimethylolpropane tri (meth) acrylate.

Examples of the (meth) acrylamide monomer include N-methylol (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 (meth) acrylamide, N- [ 2- (1-methylpropoxy) ethyl ] -meth (meth) acrylamide, N- (propoxymethyl) acrylamide, N- (1-methylethoxy) ethyl ] -meth) acrylamide, N- (2-propoxymethyl, N- [ 2- (2-methylpropoxy) ethyl ] -meth (acrylamide), N- (2-butoxyethyl) (meth) acrylamide, N- [ 2- (1, 1-dimethylethoxy) ethyl ] -meth (acrylamide, etc. Among them, N- (methoxymethyl) acrylamide, N- (ethoxymethyl) acrylamide, N- (propoxymethyl) acrylamide, N- (butoxymethyl) acrylamide and N- (2-methylpropoxymethyl) acrylamide are preferable.

The weight average molecular weight (Mw) of the (meth) acrylic resin (a) is preferably 50 to 250 ten thousand. When the weight average molecular weight is 50 ten thousand or more, the durability of the pressure-sensitive adhesive sheet in a high-temperature environment is improved, and troubles such as peeling of an adherend from the pressure-sensitive adhesive sheet and cohesive failure of the pressure-sensitive adhesive sheet are likely to be suppressed. The weight average molecular weight is advantageously 250 ten thousand or less from the viewpoint of coatability. From the viewpoint of satisfying both the durability of the pressure-sensitive adhesive sheet 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) expressed 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, and more preferably 3 to 6. The weight average molecular weight can be analyzed by gel permeation chromatography and is a value in terms of standard polystyrene.

When the (meth) acrylic resin (A) is dissolved in ethyl acetate to give a 20 mass% concentration solution, the viscosity at 25 ℃ is preferably 20 pas or less, 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 glass transition temperature (Tg) of the (meth) acrylic resin (A) is, for example, -60 to 20 ℃, preferably-50 to 15 ℃, more preferably-45 to 10 ℃, and particularly preferably-40 to 0 ℃. When Tg is not more than the upper limit, wettability of the pressure-sensitive adhesive sheet to an adherend substrate is favorably improved, and when Tg is not less than the lower limit, durability of the pressure-sensitive adhesive sheet is favorably improved. The glass transition temperature can be measured by a Differential Scanning Calorimeter (DSC).

The (meth) acrylic resin (a) 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. The solution polymerization method includes, for example, a method of mixing a monomer and an organic solvent, adding a thermal polymerization initiator in a nitrogen atmosphere, and stirring at a temperature of about 40 to 90 ℃, preferably about 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 the organic solvent.

As the polymerization initiator, a thermal polymerization initiator, a photopolymerization initiator, or the like is 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 (meth) acrylic resin (A). Polymerization using active energy rays (e.g., ultraviolet rays) can also be used for the polymerization of the (meth) acrylic resin.

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 content of the (meth) acrylic resin (a) is usually 60 to 99.9 mass%, preferably 70 to 99.5 mass%, and more preferably 80 to 99 mass% in 100 mass% of the adhesive composition.

The crosslinking agent (B) reacts with the polar functional group (for example, hydroxyl group, amino group, carboxyl group, heterocyclic group, etc.) in the (meth) acrylic resin (a). The crosslinking agent (B) forms a crosslinked structure with a (meth) acrylic resin or the like, and forms a crosslinked structure advantageous for durability and reworkability.

Examples of the crosslinking agent (B) include isocyanate crosslinking agents, epoxy crosslinking agents, aziridine crosslinking agents, and metal chelate crosslinking agents, 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 speed, 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, aromatic isocyanate compounds (e.g., toluene diisocyanate, xylylene diisocyanate), aliphatic isocyanate compounds (e.g., hexamethylene diisocyanate), adducts of these compounds with a polyol compound (e.g., glycerin, trimethylolpropane), or isocyanurate compounds can be representatively exemplified. When the crosslinking agent (B) is an aromatic isocyanate compound and/or an adduct thereof using a polyol compound or an isocyanurate compound, it may be advantageous to form an optimum crosslinking density (or crosslinking structure) and improve the durability of the pressure-sensitive adhesive layer. In particular, when the adhesive layer is a toluene diisocyanate based compound and/or an adduct thereof using a polyol compound, the durability can be improved even when the adhesive layer is applied to a polarizing plate or the like.

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 (meth) acrylic resin (a).

The adhesive composition of the present invention may further comprise 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 and 3-mercaptopropyltrimethoxysilane.

The silane compound (D) may also be a silicone oligomer. Specific examples of the silicone oligomer are shown below when the silicone oligomer is expressed in the form of a combination of monomers.

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 (d 1). When the pressure-sensitive adhesive composition contains a silane compound represented by the following formula (d1), the pressure-sensitive adhesive composition can further improve the adhesion to a substrate, glass, a transparent electrode, or the like, and thus can form a pressure-sensitive adhesive layer having good durability in which peeling off or foaming is less likely to occur in a high-temperature environment.

(wherein B represents a C1-20 alkanediyl group or a C3-20 divalent alicyclic hydrocarbon group, -CH constituting the alkanediyl group and the alicyclic hydrocarbon group₂-may be replaced by-O-or-CO-, R^d7Represents an alkyl group having 1 to 5 carbon atoms, R^d8、R^d9、R^d10、R^d11And R^d12Each independently represents an alkyl group having 1 to 5 carbon atoms or an alkoxy group having 1 to 5 carbon atoms)

In the formula (d1), B represents alkanediyl having 1 to 20 carbon atoms such as methylene, ethylene, trimethylene, tetramethylene, hexamethylene, heptamethylene, octamethylene, etc.; a divalent alicyclic hydrocarbon group having 3 to 20 carbon atoms such as a cyclobutyl group (e.g., 1, 2-cyclobutyl group), a cyclopentyl group (e.g., 1, 2-cyclopentyl group), a cyclohexyl group (e.g., 1, 2-cyclohexyl group), a cyclooctylene group (e.g., 1, 2-cyclooctylene group), or the like, -CH constituting these alkanediyl group and the alicyclic hydrocarbon group₂-a group displaced by-O-or-CO-. Preferably, B is an alkanediyl group having 1 to 10 carbon atoms. R^d7Represents an alkyl group having 1 to 5 carbon atoms such as methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl, pentyl, etc., R^d8、R^d9、R^d10、R^d11And R^d12Each independently represents the R²¹Examples of the (C1-5) alkyl group include a C1-5 alkyl group, and a C1-5 alkoxy group such as a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, a sec-butoxy group, and a tert-butoxy group. Preferred R^d8、R^d9、R^d10、R^d11And R^d12Each independently an alkoxy group having 1 to 5 carbon atoms. These silane compounds (d) may be used alone or in combination of two or more.

Specific 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, bis (tri-C1-5 alkoxysilyl) C1-10 alkanes such as 8-bis (triethoxysilyl) octane and 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 alkoxy-di C1-5 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 (meth) acrylic resin (a). When the content is not more than the upper limit, bleeding of the silane compound (d) from the pressure-sensitive adhesive layer is favorably suppressed, and when the content is not less than the lower limit, adhesiveness (or adhesiveness) between the pressure-sensitive adhesive layer and the metal layer, the glass substrate, or the like is easily improved, and peeling resistance or the like is favorably improved.

The adhesive composition may further contain 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. Examples of the ionic compound include conventional ionic compounds. 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 ion, potassium ion, sodium ion, and cesium ion, and alkaline earth metal cations such as magnesium ion and calcium ion. In particular, from the viewpoint of compatibility with the (meth) acrylic resin, a pyridinium cation, an imidazolium cation, a pyrrolidinium cation, a lithium ion, and a potassium ion are preferable. The anionic component constituting the ionic compound may be any of inorganic anions and organic anions, but from the viewpoint of antistatic performance, an anionic component containing a fluorine atom is preferable. 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. Particular preference is given to 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 property 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 antistatic agent is contained in an amount of, 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, based on 100 parts by mass of the (meth) acrylic resin (a).

The adhesive composition may contain 1 or 2 or more kinds of additives such as a solvent, a crosslinking catalyst, a thickener, a plasticizer, a softener, a pigment, a rust preventive, an inorganic filler, and light-scattering fine particles.

< adhesive layer and optical film with adhesive layer constitution and manufacturing method >

The adhesive sheet of the present invention can be formed, for example, by dissolving or dispersing the adhesive composition in a solvent to prepare a solvent-containing adhesive composition, applying the composition to the surface of a substrate, and drying the composition. Examples of the optical film with an adhesive layer include a method in which an optical film is laminated on the adhesive sheet surface of the substrate with an adhesive sheet formed as described above and then the substrate is peeled off, and a method in which an adhesive composition is applied to a resin film such as an optical film and dried.

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 those obtained by subjecting one surface of a film made of a resin such as polyethylene terephthalate, polybutylene terephthalate, polycarbonate, or polyarylate to a mold release treatment such as a silicone treatment. For temporary protection of the adhesive sheet, a release film may be attached to the adhesive sheet.

Fig. 1 shows an example of the layer structure of the adhesive sheet of the present invention. The pressure-sensitive adhesive sheet 1 shown in fig. 1 is in a state in which a release film 2 is attached for temporary protection. The release film may be laminated on one side or both sides of the pressure-sensitive adhesive sheet.

An 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. Fig. 2 to 4 show an optical laminate including the pressure-sensitive adhesive sheet of the present invention. 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 sheet 1, and a release film 2. The protective film 3 may have a phase difference. The layers of the protective film 8, the adhesive layer 7, the polarizing film 9, the adhesive layer 7, and the protective film 3 constitute a polarizing plate corresponding to the optical film 40. The optical laminate 10B shown in fig. 3 and the optical laminate 10C shown in fig. 4 are optical laminates each including a protective film 8, an adhesive layer 7, a polarizing film 9, an adhesive layer 7, a protective film 3, an adhesive sheet 1, an optical film 40, an adhesive layer 7a, and a light-emitting element 30 (liquid crystal cell, OLED cell), and the optical film 40 is an optical film having a multilayer structure.

The optical film 40 has optical functions such as transmission, reflection, and absorption of light, and may be a single-layer film or a multilayer film. Examples of the optical film 40 include a polarizing film (polarizing plate), a retardation 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 retardation film, a window film, or a laminate thereof.

The retardation film is an optical film exhibiting optical anisotropy, and examples thereof include a stretched film 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 about 1.01 to 6 times. Among them, a polymer film obtained by uniaxially or biaxially stretching a polycarbonate film or a cycloolefin resin film is preferable. In the present specification, the retardation film includes a zero retardation film, and also includes films such as a uniaxial retardation film, a low photoelastic rate retardation film, and a wide viewing angle retardation film.

Examples of the Film exhibiting optical anisotropy by coating and alignment of a liquid crystal compound and the Film exhibiting optical anisotropy by coating of an inorganic layered compound include a Film called a temperature compensation type retardation Film, "NH Film" (trade name; Film in which rod-like liquid crystal is obliquely oriented) sold by JX liquid crystal Film, "WV Film" (trade name; Film in which discotic liquid crystal is obliquely oriented) sold by fuji Film co.

The zero retardation film means a front retardation R_eRetardation R with respect to the thickness direction_thAll of them are-15 to 15nm and optically isotropic films. Examples of the zero retardation film include resin films 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 the cellulose-based resin or the polyolefin-based resin is preferable in terms of easy control and acquisition of the retardation value. The zero retardation film may be used as a protective film. Examples of the ZERO retardation film include "Z-TAC (trade name)" sold by fuji film co, "ZERO TAC (registered trademark)" sold by Konica Minolta co, and "ZF-14 (trade name)" sold by japan Zeon co.

In the optical film of the present invention, the retardation film is preferably a retardation film obtained by curing a polymerizable liquid crystal compound.

Examples of the film exhibiting optical anisotropy by application and alignment of a liquid crystalline compound include a first formula: a retardation film in which a rod-like liquid crystal compound is aligned in a horizontal direction with respect to a support substrate, a second embodiment: a retardation film in which a rod-like liquid crystal compound is aligned in a vertical direction with respect to a support substrate, the third formula: a retardation film in which the in-plane orientation direction of the rod-like liquid crystal compound changes in a spiral manner, the fourth formula: retardation film in which discotic liquid crystal compound is obliquely aligned, fifth embodiment: a biaxial retardation film in which the discotic liquid crystal compound is aligned in a direction perpendicular to the support substrate.

For example, the first, second, and fifth embodiments can be suitably used as an optical film used for an organic electroluminescent display. Alternatively, they may be stacked 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 the retardation value in the liquid crystal alignment plane at a short wavelength is smaller than the retardation value in the liquid crystal alignment plane at a long wavelength, and the retardation film preferably 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 mode and has reverse wavelength dispersibility, coloration at the time of black display in a display device is reduced, and therefore, it is preferable that in the above formula (7), 0.82. ltoreq. Re (450)/Re (550). ltoreq.0.93 is more preferable. Further preferably 120. ltoreq. Re (550). ltoreq.150.

When the retardation film is a film having an optically anisotropic layer, examples thereof include 3.8.6 ネットワーク (complete type) (network (completely crosslinked type)) published by liquid crystal laboratory list (liquid crystal laboratory editorial committee, published by pill-mart, 12 years, 10 months and 30 days), a compound having a polymerizable group among compounds described in "6.5.1 liquid crystal material b." superimposed ネマチック liquid crystal material (polymerizable nematic liquid crystal material) ", and polymerizable liquid crystal compounds described in japanese patent application laid-open nos. 2010-31223, 2010-270108, 2011-6360, 2011-207765, 2011-162162678, 2016-81035, 2017/043438 and 2011-207765.

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 preferably adjusted to a range of-10 to-300 nm, more preferably-20 to-200 nm. Thickness-direction phase difference value R representing thickness-direction refractive index anisotropy_thThe phase difference value R that can be measured by tilting 50 degrees with the fast axis in the plane as the tilt axis₅₀Phase difference value R in sum plane₀And (6) calculating. Namely, the phase difference value R in the thickness direction_thCan be calculated from the in-plane phase difference value R₀And a phase difference value R measured by tilting the fast axis by 50 degrees 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_zThese 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)

R₅₀＝(n_x－n_y＇)×d/cos(φ) (11)

(n_x+n_y+n_z)/3＝n₀(12)

Here, the number of the first and second electrodes,

φ＝sin^－1〔sin(40°)/n₀〕

n_y＇＝n_y×n_z/〔n_y ²×sin²(φ)+n_z ²×cos²(φ)〕^1/2

the phase difference film may be a multilayer film having two or more layers. For example, a multilayer film obtained by laminating a protective film on one surface or both surfaces of a retardation film, or a multilayer film obtained by laminating two or more retardation films with an adhesive or a bonding agent may be mentioned.

The thickness of the retardation film is usually 0.1 to 100 μm.

When the retardation film is a multilayer film, the total thickness may be 0.5 to 200 μm.

In the case where the optical film 40 is a multilayer film obtained by laminating two or more retardation films, as shown in fig. 3, an optical laminate including the optical film of the present invention includes an optical film 40 obtained by laminating a 1/4 wavelength retardation layer 50 which imparts a retardation of 1/4 parts in wavelength to transmitted light and a 1/2 wavelength retardation layer 70 which imparts a retardation of 1/2 parts in wavelength to transmitted light via an adhesive or a pressure-sensitive adhesive 60. As shown in fig. 4, an optical film 40 including an 1/4 wavelength retardation layer 50a and a positive C layer 80 laminated via an adhesive layer or a pressure-sensitive adhesive layer may be used.

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 the transmitted light in fig. 3 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. 3, at least one of them is more preferably the fifth aspect.

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

The polarizing film has a property of absorbing linearly polarized light having a vibration plane parallel to the absorption axis thereof and transmitting linearly polarized light having a vibration plane 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.

In general, a material obtained by forming a film of a polyvinyl alcohol resin is used as a 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 performing a step of uniaxially stretching a raw material film, a step of dyeing the film with a dichroic dye and adsorbing the dichroic dye, a step of treating the film with an aqueous boric acid solution, and a step of washing the film with water, and finally drying the film. The thickness of the polarizing plate 2 is usually 1 to 30 μm, and from the viewpoint of making the optical film 1 with an adhesive layer thinner, it is preferably 20 μm or less, more preferably 15 μm or less, and particularly preferably 10 μm or less.

A polarizing film in which a dichroic dye is adsorbed on a polyvinyl alcohol resin film and oriented can be obtained by a method (1)) in which a single film of the polyvinyl alcohol resin film is used as a raw material film, and the film is subjected to uniaxial stretching treatment and dyeing treatment of the dichroic dye, and a method (2)) in which a coating liquid (aqueous solution or the like) containing a polyvinyl alcohol resin is applied to a base material film, dried to obtain a base material film having a polyvinyl alcohol resin layer, and then the base material film is uniaxially stretched together with the base material film, and the stretched polyvinyl alcohol resin layer is subjected to dyeing treatment of the dichroic dye, and then the base material film is peeled off and removed. As the base film, a film containing a thermoplastic resin similar to the thermoplastic resin can be used, and preferably a film containing a polyester resin such as polyethylene terephthalate, a polycarbonate resin, a cellulose resin such as triacetyl cellulose, a cyclic polyolefin resin such as a norbornene resin, a polystyrene resin, or the like. By the above method (2), a polarizing film of a film can be easily produced, and for example, the production of the polarizing plate 2 having a thickness of 7 μm or less can be easily performed.

At least one surface of the polarizing film is preferably provided with a protective film via an adhesive.

As the adhesive, a known adhesive may be used, and may be a water-based adhesive or an active energy ray-curable adhesive.

Examples of the aqueous adhesive include conventional aqueous adhesives (for example, adhesives containing an aqueous polyvinyl alcohol resin solution, aqueous two-part 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 an aqueous adhesive, it is preferable to perform a step of drying the polarizing film in order to remove water contained in the aqueous adhesive after the polarizing film and the protective film are bonded to each other. After the drying step, a curing step of curing at a temperature of about 20 to 45 ℃ may be provided, for example. The adhesive layer formed of the aqueous adhesive is usually 0.001 to 5 μm.

The active energy ray-curable adhesive is an adhesive that is cured by irradiation with an active energy ray such as ultraviolet ray or electron beam, 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.

In the case of using an active energy ray-curable adhesive, after the polarizing film and the protective film are bonded, a drying step is performed as necessary, and then a curing step of curing the active energy ray-curable adhesive by irradiation with an active energy ray is performed. The light source of the active energy ray is not particularly limited, but ultraviolet rays having an emission distribution at a wavelength of 400nm or less are preferable. The adhesive layer formed by the active energy ray curing adhesive is usually 0.1-20 μm.

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

A preferable configuration 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 triacetylcellulose-based resin or a cycloolefin-based resin. The protective film may be an unstretched film or may be stretched in any direction to have a retardation. A surface treatment layer such as a hard coat layer or an antiglare layer may be provided on the surface of the protective film laminated on the visible side.

When the protective films are laminated on both surfaces 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.

Between the polarizing plate and the panel, another layer or film may be further laminated. When used as a circularly polarizing plate for an organic EL display, it is preferable to laminate a retardation layer having an 1/4-wavelength retardation layer and a 1/2-wavelength retardation layer, and a 1/4-wavelength layer having the above-mentioned reverse wavelength dispersibility. The retardation layer is preferably a liquid crystal retardation film from the viewpoint of making the film thinner.

The light-collecting film is a film used for the purpose of optical path control or the like, and may be a prism array sheet, a lens array sheet, a sheet with dots attached thereto, 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 are a reflective polarization separation sheet in which a plurality of films having different refractive index anisotropy are stacked to produce anisotropy in reflectance, a circularly polarized light separation sheet in which an alignment film of a cholesteric liquid crystal polymer or an alignment liquid crystal layer thereof is supported on a base film, and the like.

The window film is a front panel of a flexible liquid crystal 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 a composite 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 provided on the surface thereof for imparting 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 optical laminate comprising the pressure-sensitive adhesive layer of the present invention can be laminated on a display element such as an organic EL element or a liquid crystal cell, and used in a display device (FPD: flat panel display) such as an organic EL display device or a liquid crystal display device.

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.

In the following examples, the weight average molecular weight and the number average molecular weight were measured by a gel permeation chromatography (hereinafter referred to as GPC.) apparatus (GPC-8120, manufactured by Tosoh) in which a total of 5 "TSK gel XL (manufactured by Tosoh) and 5" Shodex GPC KF-802 (manufactured by showa electrician) were arranged in series as a column, and the measurement was performed using tetrahydrofuran as an eluent under conditions of a sample concentration of 5mg/mL, a sample introduction amount of 100 μ L, a temperature of 40 ℃, and a flow rate of 1 mL/min, and calculated in terms of standard polystyrene.

Synthesis example 1 Synthesis of light-selective absorbing Compound (1)

A200 mL-four-necked flask equipped with a Dimrot condenser and a thermometer was placed in a nitrogen atmosphere, and 10 parts of the compound represented by the formula (aa) synthesized by reference to the patent document (Japanese unexamined patent publication No. 2014-194508), 3.6 parts of acetic anhydride (available from Wako pure chemical industries, Ltd.), 6.9 parts of 2-ethylhexyl cyanoacetate (sometimes referred to as DIPEA; available from Tokyo chemical industries, Ltd.), and 60 parts of acetonitrile (available from Wako pure chemical industries, Ltd.) were added thereto, followed by stirring with a magnetic stirrer. 4.5 parts of DIPEA (manufactured by Tokyo chemical industry Co., Ltd.) was added dropwise from a dropping funnel at an internal temperature of 25 ℃ over 1 hour, and after completion of the addition, the mixture was further kept at an internal temperature of 25 ℃ for 2 hours. After the reaction was completed, acetonitrile was removed by a reduced pressure evaporator, and the product was subjected to column chromatography (silica gel) to purify the product, and the effluent containing the light selective absorbing compound (1) represented by the formula (aa1) was subjected to solvent removal by a reduced pressure evaporator to obtain yellow crystals. The crystals were dried under reduced pressure at 60 ℃ to obtain 4.6 parts of the light selective absorbing compound (1) as a yellow powder. The yield thereof was found to be 50%.

To carry out¹As a result of H-NMR analysis, the following peaks were observed, and it was confirmed that the light selective absorbing compound 1 was produced.

¹H－NMR(CDCl₃)δ：0.87－0.94(m，6H)、1.32－1.67(m，8H)、1.59－1.66(m，2H)、2.09(quin，2H)、3.00(m，5H)、3.64(t，2H)、4.10(dd，2H)、5.52(d，2H)、7.87(d，2H)

< g absorptivity ε measurement >

In order to measure the gram absorption coefficient of the obtained light selective absorbing compound (1), the light selective absorbing compound (1) was dissolved in 2-butanone. The obtained solution (0.006g/L) was placed in a 1cm quartz cell, the quartz cell was placed in a spectrophotometer UV-2450 (manufactured by Shimadzu corporation), and the absorbance was measured in a wavelength range of 300 to 800nm in 1nm step by the two-beam method. From the obtained absorbance value, the concentration of the light-absorbing compound in the solution, and the optical path length of the quartz cell, the gram absorption coefficient for each wavelength was calculated using the following formula.

ε(λ)＝A(λ)/CL

[ in the formula, [ epsilon ] (lambda) ] represents a gram absorption coefficient L/(g · cm) of the compound at a wavelength of lambda nm, A (lambda) represents an absorbance at the wavelength of lambda nm, C represents a concentration g/L, and L represents an optical path length cm of the quartz cell. Angle (c)

As a result of measuring the absorption maximum wavelength (λ max) of the light selective absorbing compound (1), λ max is 389nm (2-butanone), the value of ∈ (405) is 47L/(g · cm), the value of ∈ (440) is 0.1L/(g · cm) or less, and the value of ∈ (405)/∈ (440) is 80 or more.

(Synthesis example 2) Synthesis of light-selective absorbing Compound (2)

In a 200 mL-four-necked flask equipped with a Dimrot condenser and a thermometer, 10g of the compound represented by the formula (aa) synthesized by reference to Japanese patent application laid-open No. 2014-194508, 3.6g of acetic anhydride (manufactured by Wako pure chemical industries, Ltd.), 10g of 2-butyloctyl cyanoacetate (manufactured by Tokyo Kasei Co., Ltd.), and 60g of acetonitrile (manufactured by Wako pure chemical industries, Ltd.) were charged in a nitrogen atmosphere, and stirred with a magnetic stirrer. 4.5g of DIPEA (manufactured by Tokyo chemical industry Co., Ltd.) was added dropwise to the obtained mixture at an internal temperature of 25 ℃ over 1 hour, and the mixture was further kept at an internal temperature of 25 ℃ for 2 hours. Thereafter, acetonitrile was removed using a reduced pressure evaporation apparatus, column chromatography (silica gel) was performed to purify, and the effluent containing the compound represented by formula (aa2) was subjected to solvent removal using a reduced pressure evaporation apparatus to obtain yellow crystals. The crystals were dried under reduced pressure at 60 ℃ to thereby obtain 4.6g of the compound represented by the formula (aa2) (light selective absorbing compound (2)) in the form of yellow powder. The yield thereof was found to be 56%.

When the gram absorbance coefficient was determined by the same method as described above, the value of ε (405) and ε (420) of the compound represented by formula (aa2) were 45L/(g cm) and 2.1L/(g cm).

(Synthesis example 3 Synthesis of (meth) acrylic resin

A reaction vessel equipped with a condenser, a nitrogen inlet, a thermometer and a stirrer was charged with a solution obtained by mixing 81.8 parts of ethyl acetate as a solvent, 70.4 parts of butyl acrylate as a monomer, 20.0 parts of methyl acrylate, 8.0 parts of 2-phenoxyethyl acrylate, 1.0 part of 2-hydroxyethyl acrylate and 0.6 part of acrylic acid. The air in the reaction vessel was replaced with nitrogen, and the internal temperature was adjusted to 60 ℃. Thereafter, a solution prepared by dissolving 0.12 parts of azobisisobutyronitrile in 10 parts of ethyl acetate was added. After the same temperature was maintained for 1 hour, ethyl acetate was continuously fed into the reaction vessel at an addition rate of 17.3 parts/Hr while maintaining the internal temperature at 54 to 56 ℃ so that the concentration of the polymer was approximately 35%. After the internal temperature was maintained at 54 to 56 ℃ from the start of the addition of ethyl acetate until 12 hours elapsed, ethyl acetate was added to adjust the polymer concentration to 20% to obtain an ethyl acetate solution (1) of a (meth) acrylic resin. The weight average molecular weight Mw of the (meth) acrylic resin was 139 ten thousand, and the ratio Mw/Mn of the weight average molecular weight Mw to the number average molecular weight Mn was 5.32.

The weight average molecular weight and the number average molecular weight were measured by arranging 4 "TSK gel XL (manufactured by Tosoh corporation)" and 1 "Shodex GPC KF-802 (manufactured by showa electric corporation)" in a total of 5 columns in a GPC apparatus as a column, using tetrahydrofuran as an eluent, under conditions of a sample concentration of 5mg/mL, a sample introduction amount of 100 μ L, a temperature of 40 ℃, and a flow rate of 1 mL/min, and calculating in terms of standard polystyrene.

Synthesis example 4 Synthesis of adhesive composition (1)

An adhesive composition (1) was obtained by mixing 0.4 parts of a crosslinking agent, 0.4 parts of a silane compound, 2 parts of the photoselective absorptive compound (1) synthesized in synthesis example 1, and 2.0 parts of Sumisorb 350 (manufactured by Chemtex corporation) with 100 parts of the solid content of the ethyl acetate solution (1) (resin concentration: 20%) of the (meth) acrylic resin obtained in synthesis example 3, and then adding ethyl acetate so that the solid content concentration was 14%. The amount of the crosslinking agent is the weight part as an active ingredient.

Details of the crosslinking agent and the silane compound used in synthesis example 4 are as follows.

A crosslinking agent: an ethyl acetate solution (solid content concentration: 75%) of a trimethylolpropane adduct of tolylene diisocyanate, and a trade name "Coronate L" obtained from Tosoh corporation.

Silane compound: 3-glycidoxypropyltrimethoxysilane, available from shin-Etsu chemical Co., Ltd under the trade name "KBM 403".

Synthesis example 5 Synthesis of adhesive composition (2)

An adhesive composition (2) was obtained in the same manner as in synthesis example 4, except that 2.0 parts of the light selective absorbing compound (2) obtained in synthesis example 2 and 1.0 part of 2-hydroxy-4-methoxybenzophenone (manufactured by tokyo chemical industries, ltd.) were replaced with the light selective absorbing compound (2).

Synthesis example 6 Synthesis of adhesive composition (3)

An adhesive composition (3) was obtained in the same manner as in synthesis example 4, except that the light selective absorbing compound was replaced with 1.0 part of the light selective absorbing compound (2) and EST-5 (manufactured by sumitomo chemical corporation) obtained in synthesis example 2.

Synthesis example 7 Synthesis of adhesive composition (4)

A (meth) acrylic resin adhesive composition (7) was obtained in the same manner as in synthesis example 4, except that the light selective absorbing compound was changed to only 2 parts of the light selective absorbing compound (1) obtained in synthesis example 1 and that sumiosorb 350 was not mixed.

Synthesis example 8 Synthesis of adhesive composition (5)

A (meth) acrylic resin adhesive composition (5) was obtained in the same manner as in synthesis example 4, except that the light selective absorbing compound was changed to only 2 parts of the light selective absorbing compound (2) obtained in synthesis example 2, and sumiosorb 350 was not mixed.

< production of adhesive sheet >

Example 1 production of adhesive sheet (1)

The obtained adhesive composition (1) was applied to a release-treated surface of a release film (trade name "PLR-382190" available from linetec corporation) comprising a polyethylene terephthalate film, which was subjected to release treatment, using an applicator so that the thickness after drying was 15 μm, and dried at 100 ℃ for 1 minute to produce an adhesive layer (1).

The obtained pressure-sensitive adhesive layer (1) was bonded to a 23 μm cycloolefin film by a laminator, and then aged at a temperature of 23 ℃ and a relative humidity of 65% for 7 days to obtain a pressure-sensitive adhesive sheet (1).

Example 2 production of adhesive sheet (2)

An adhesive sheet (2) was obtained in the same manner as in example 1, except that the adhesive composition was replaced with the adhesive composition (2) obtained in synthesis example 5.

Example 3 production of adhesive sheet (3)

An adhesive sheet (3) was obtained in the same manner as in example 1, except that the adhesive composition was replaced with the adhesive composition (3) obtained in synthesis example 6.

Comparative example 1 production of adhesive sheet (4)

An adhesive sheet (4) was obtained in the same manner as in example 1, except that the adhesive composition was replaced with the adhesive composition (4) obtained in synthesis example 7.

Comparative example 2 production of adhesive sheet (5)

An adhesive sheet (5) was obtained in the same manner as in example 1, except that the adhesive composition was replaced with the adhesive composition (5) obtained in synthesis example 8.

Production of polarizing plate with adhesive

Production example 1 production of polarizing plate film

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 (trade name "Kuraray Vinylon VF-PE # 3000", manufactured by Kuraray Co., Ltd.) was immersed in pure water at 37 ℃ and then immersed in an aqueous solution containing iodine and potassium iodide (iodine/potassium iodide/water (mass ratio): 0.04/1.5/100) at 30 ℃. Thereafter, the resultant was immersed in an aqueous solution containing potassium iodide and boric acid (potassium iodide/boric acid/water (mass ratio) ═ 12/3.6/100) at 56.5 ℃. The film was washed with pure water at 10 ℃ and then dried at 85 ℃ to obtain a polarizing plate having a thickness of about 12 μm in which iodine was adsorbed and oriented to 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.

On one side of the obtained polarizing plate, a transparent protective film (trade name "KC 2 UA" manufactured by Konica Minolta Opto, hereinafter sometimes referred to as "TAC film") comprising a triacetyl cellulose film having a thickness of 25 μm was bonded via an adhesive containing an aqueous solution of a polyvinyl alcohol resin. Then, a zero-retardation film (hereinafter, sometimes referred to as "ZEONOR" product name manufactured by Zeon corporation, japan) comprising a cyclic polyolefin resin having a thickness of 23 μm was laminated on the surface of the polarizer opposite to the triacetyl cellulose film via an adhesive comprising an aqueous solution of a polyvinyl alcohol resin, and a polarizing plate was manufactured.

Example 4 production of polarizing plate with adhesive (1)

A polarizing plate (1) with an adhesive was obtained in the same manner as in example 2, except that the 23 μm cycloolefin film was replaced with the polarizing plate obtained in production example 1. The polarizing plate (1) with an adhesive layer has a structure of TAC film/adhesive layer/polarizing film/adhesive layer/COP film/adhesive layer.

Example 5 production of polarizing plate with adhesive (2)

A polarizing plate (2) with an adhesive was obtained in the same manner as in example 3, except that the 23 μm cycloolefin film was replaced with the polarizing plate obtained in production example 1. The polarizing plate (2) with an adhesive layer has a structure of TAC film/adhesive layer/polarizing film/adhesive layer/COP film/adhesive layer.

Comparative example 3 production of adhesive-Equipped polarizing plate (3)

A polarizing plate (3) with an adhesive was obtained in the same manner as in comparative example 2, except that the 23 μm cycloolefin film was replaced with the polarizing plate obtained in production example 1. The polarizing plate (3) with an adhesive layer has a structure of TAC film/adhesive layer/polarizing film/adhesive layer/COP film/adhesive layer.

< measurement of Absorbance of adhesive sheet >

The obtained adhesive sheet-attached film (1) was cut into a size of 30mm × 30mm, and the adhesive sheet was attached to alkali-free glass (trade name "EAGLE XG" manufactured by Corning corporation), to prepare a sample. The absorbance of the sample was measured in the wavelength range of 300 to 800nm using a spectrophotometer (UV-2450, manufactured by Shimadzu corporation). The results are shown in table 1. The higher the absorbance retention, the less the light selective absorption function is deteriorated, and the better the weather resistance is exhibited. The absorbances of the COP film monomer and the alkali-free glass monomer at a wavelength of 350nm, a wavelength of 405nm, and a wavelength of 440nm were all 0.

The sample after the absorbance measurement was put into a sunshine weathering test chamber (manufactured by Suga test machine Co., Ltd.) at 63 ℃ under 50% relative humidity for 24 hours, and a weathering test was performed for 24 hours. The absorbance of the sample taken out was measured by the same method as described above. From the measured absorbance, the absorbance retention of the sample at 405nm was determined based on the following formula. The results are shown in table 1.

Absorbance retention rate (a (405) after durability test/a (405) before durability test) x 100

[ TABLE 1]

< measurement of Absorbance of polarizing plate with adhesive >

The polarizing plate with an adhesive thus obtained was cut into a size of 30mm × 30mm, and then the adhesive layer was bonded to a glass substrate to obtain a measurement sample. The layer constitution of the measurement sample was glass substrate/adhesive layer/COP film/adhesive layer/polarizing plate/adhesive layer/TAC film. As the glass substrate, an alkali-free glass substrate [ trade name "EagleXG" manufactured by Corning corporation ] was used.

The obtained measurement sample was measured for the transmission spectrum in the transmission axis direction and the absorption axis direction of the polarizing plate in the wavelength range of 380 to 780nm using an integrating-sphere-equipped spectrophotometer [ product name "V7100" manufactured by japan spectrography, ltd.), and the absorbance of the polarizing plate with an adhesive layer was calculated from the transmission spectrum in the transmission axis direction of the polarizing plate. In addition, it was confirmed that the polarizing plate with an adhesive was inhibited from deterioration under visible light having a short wavelength of 405 nm. The absorbance at wavelengths of 405nm and 440nm of the TAC film monomer, COP film monomer, and alkali-free glass monomer were all 0.

[ TABLE 2]

As shown in Table 1, the pressure-sensitive adhesive sheet of the present invention was excellent in the light absorption function at a wavelength of around 350nm and the light absorption function at a wavelength of around 405 nm. Therefore, when the pressure-sensitive adhesive sheet of the present invention is laminated on a retardation film or an organic EL device, the pressure-sensitive adhesive sheet of the present invention can block ultraviolet rays and light having a wavelength of about 405nm that are incident on the retardation film or the organic EL device, and can suppress deterioration of the retardation film or the organic EL device due to both ultraviolet rays and visible light having a short wavelength. The pressure-sensitive adhesive sheet of the present invention has a good light absorption function at a wavelength of around 405nm even after a weather resistance test, and has good weather resistance (durability). The pressure-sensitive adhesive sheet of the present invention has low light absorption performance at a wavelength around 440nm, and can exhibit a good color without inhibiting light emission of a liquid crystal display device.

As shown in table 2, the optical film with an adhesive sheet of the present invention has a good light absorption function at a wavelength of around 405 nm. Further, even after the weather resistance test, the light absorbing function at a wavelength of about 405nm was good, and the weather resistance (durability) was good.

Industrial applicability

The adhesive sheet and the optical film with the adhesive sheet of the present invention can be suitably used for a liquid crystal panel and a liquid crystal display device.

Description of the symbols

1 pressure-sensitive adhesive sheet, 2 release film, 10A, 10B, 10C optical laminate, 3 protective film, 4 optical film, 7, 60 adhesive layer, 7a pressure-sensitive adhesive layer, 8 protective film, 9 polarizing film, 30 light-emitting element, 40 optical film, 50A 1/4 wavelength retardation layer, 60 adhesive layer, 701/2 wavelength retardation layer, 80 positive C layer.

Claims

1. An adhesive sheet comprising an adhesive composition containing a (meth) acrylic resin (A) and a light selective absorbing compound, and satisfying the following formulae (1) and (2):

A(350)≥0.5 (1)

A(405)≥0.5 (2)

in the formula (1), A (350) represents the absorbance at a wavelength of 350 nm;

in the formula (2), A (405) represents the absorbance at a wavelength of 405 nm.

2. The adhesive sheet according to claim 1, further satisfying the following formula (3):

A(440)≤0.1 (3)

in formula (3), A (440) represents the absorbance at a wavelength of 440 nm.

3. The adhesive sheet according to claim 1, further satisfying 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.

4. The adhesive sheet according to any one of claims 1 to 3,

the light selective absorbing compound includes a compound that selectively absorbs light having a wavelength of 350nm and a compound that selectively absorbs light having a wavelength of 405 nm.

5. The adhesive sheet according to claim 4,

the compound that selectively absorbs light having a wavelength of 405nm is a compound satisfying formula (5):

ε(405)≥20 (5)

in the formula (5), ε (405) represents the gram absorption coefficient of a compound at a wavelength of 405 nm; the unit of the gram absorption coefficient is L/(g.cm).

6. The adhesive sheet according to claim 5,

the compound that selectively absorbs light having a wavelength of 405nm is a compound satisfying formula (6):

ε(405)/ε(440)≥20 (6)

in the formula (6), ε (405) represents the gram absorption coefficient of a compound at a wavelength of 405nm, and ε (440) represents the gram absorption coefficient at a wavelength of 440 nm.

7. The adhesive sheet according to any one of claims 4 to 6,

the compound that selectively absorbs light having a wavelength of 405nm is a compound having a merocyanine structure in the molecule.

8. The adhesive sheet according to any one of claims 1 to 7,

the adhesive composition further comprises a crosslinking agent (B).

9. The adhesive sheet according to claim 8,

the content of the crosslinking agent (B) is 0.01 to 15 parts by mass per 100 parts by mass of the (meth) acrylic resin (A).

10. The adhesive sheet according to any one of claims 1 to 9,

the content of the light selective absorbing compound is 0.01 to 20 parts by mass per 100 parts by mass of the (meth) acrylic resin (a).

11. An optical film having the adhesive layer according to any one of claims 1 to 10, which is obtained by laminating an optical film on at least one surface of an adhesive sheet.

12. The polarizing plate with an adhesive layer according to claim 11, wherein the optical film is a polarizing plate.

13. A display device comprising the adhesive-bearing optical film of any one of claims 11 or 12.