Adhesive sheet, optical laminate, and image display apparatus

Abstract

To provide a photocurable adhesive sheet adapted for an image display apparatus that can be subjected to a high-temperature environment.SOLUTION: The provided adhesive sheet is formed from a photocurable adhesive composition containing a monomer component M, the monomer component M including a predetermined monomer m represented by the following formula (1), and a value of the monomer m according to a regression equation shown by the following formula (Y) being 8.00 or more, wherein a represents a charge of X1 obtained by a Mulliken method through predetermined quantum chemical calculation, b and c represent descriptors VSA_EState5 and VSA_EState7, respectively, d represents a descriptor Num Aliphatic Heterocycles, e represents a descriptor δD, f represents a descriptor PEOE_VSA1, g represents a descriptor AntB, and each descriptor is installed in RDkit or HSPiP software, formula (Y): 20.63a-0.6602b+0.2859c+0.2797d+0.2050e+0.1180f+0.000865g-0.8069.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a pressure-sensitive adhesive sheet, and an optical laminate and an image display device that include the pressure-sensitive adhesive sheet. [Background technology]

[0002] Various image display devices, such as liquid crystal display devices and electroluminescence (EL) display devices, generally include an optical laminate including an optical substrate such as a polarizing film and an adhesive sheet. An adhesive sheet is typically used to bond layers included in the optical laminate or to bond the optical laminate to an image display panel. A typical adhesive sheet is a sheet obtained by curing monomer components, such as acrylic monomers and silicone monomers, through polymerization and crosslinking. Patent Document 1 discloses an optical laminate including an adhesive sheet formed from a photocurable adhesive composition (hereinafter, sometimes referred to as a "photocurable adhesive sheet" or "photocurable adhesive sheet") and an optical substrate. A different type of adhesive sheet from the photocurable type is a thermosetting adhesive sheet formed by thermally curing a coating layer containing an adhesive composition and a solvent. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-56510 Summary of the Invention [Problem to be solved by the invention]

[0004] When a photocurable pressure-sensitive adhesive sheet is used in an optical laminate, problems tend to occur in the quality of images displayed in an image display device that may be exposed to a high-temperature environment.

[0005] An object of the present invention is to provide a photocurable pressure-sensitive adhesive sheet suitable for use in image display devices that may be exposed to high-temperature environments. [Means for solving the problem]

[0006] [1] The pressure-sensitive adhesive sheet according to an embodiment of the present invention comprises: A pressure-sensitive adhesive sheet formed from a photocurable pressure-sensitive adhesive composition containing a monomer component M, The monomer component M includes a monomer m represented by the following formula (1): [ka] For the monomer m, the value of the regression equation shown in the following formula (Y) is 8.00 or more. Formula (Y):20.63a-0.6602b+0.2859c+0.2797d+0.2050e+0.1180f+0.000865g-0.8069 however, X in the formula (1) 1 The number of atoms that make up X 2 is smaller than the number of atoms constituting the X 3 is a hydrogen atom, or X 2 It bonds to form a ring structure, a in the formula (Y) is X in a state of being contained in the monomer m, which is obtained by standard structure optimization that can be performed by quantum chemical calculations using the density functional method with B3LYP / 6-31G(d,p) as a basis function. 1 is the charge by Mulliken's method, b and c are the descriptors VSA_EState5 and VSA_EState7, respectively, included in the RDkit software. d is the descriptor Num Aliphatic Heterocycles included in the RDkit software, e is the descriptor δD included in the HSPiP software, f is the descriptor PEOE_VSA1 included in the RDkit software, g is the descriptor AntB included in the HSPiP software. [2] In the pressure-sensitive adhesive sheet described in [1] above, the value of c may be 1.15 or more. [3] In the pressure-sensitive adhesive sheet according to the above [1] or [2], the value of g may be 1680 or more. [4] In the pressure-sensitive adhesive sheet according to any one of the above [1] to [3], the value of a may be 0.1 or more, and the value of e may be 16 or more. [5] In the pressure-sensitive adhesive sheet according to any one of [1] to [4] above, X in the formula (1) 1 may be a hydrogen atom or a methyl group. [6] In the pressure-sensitive adhesive sheet according to any one of [1] to [5] above, X in the formula (1) 2 may contain an aliphatic heterocycle. [7] In the pressure-sensitive adhesive sheet according to the above item [6], the aliphatic heterocycle may not contain a nitrogen atom. [8] In the pressure-sensitive adhesive sheet according to the above [6] or [7], the aliphatic heterocycle may be a five- or more-membered ring. [9] In the pressure-sensitive adhesive sheet according to any one of the above items [6] to [8], the aliphatic heterocycle may be a cyclic ether.

[10] In the pressure-sensitive adhesive sheet according to any one of [1] to [9] above, X in the formula (1) 3 may be a hydrogen atom.

[11] In the pressure-sensitive adhesive sheet according to any one of the above items [1] to

[10] , the monomer m may be a (meth)acrylate monomer.

[12] In the pressure-sensitive adhesive sheet according to any one of the above items [1] to

[11] , the monomer m may be a monomer represented by the following formula (2): [ka] X in the formula (2) 4 is a cyclic ether group, L is a single bond, an alkylene group, a carboxylic acid ester group, or a group in which an alkylene group and a carboxylic acid ester group are combined.

[13] In the pressure-sensitive adhesive sheet according to any one of the above [1] to

[12] , the content of the monomer m in the monomer component M may be 4 to 20 wt %.

[14] In the pressure-sensitive adhesive sheet according to any one of the above [1] to

[13] , the polymerization rate of the monomer component M in the pressure-sensitive adhesive sheet may be 95% or more.

[15] In the pressure-sensitive adhesive sheet according to any one of the above items [1] to

[14] , the monomer component M may be substantially free of a carboxyl group-containing monomer.

[16] The adhesive sheet according to any one of the above items [1] to

[15] may have a thickness of 5 to 30 μm.

[17] In the pressure-sensitive adhesive sheet according to any one of the above items [1] to

[16] , the pressure-sensitive adhesive sheet may contain a solvent in an amount of 5 wt % or less.

[18] The pressure-sensitive adhesive sheet according to any one of the above items [1] to

[17] may be used for attaching an optical substrate including a polarizing film.

[19] An optical laminate according to an embodiment of the present invention is The adhesive sheet according to any one of [1] to

[18] above and an optical substrate are included.

[20] In the optical laminate according to the above item

[19] , the optical substrate may include a polarizing film.

[21] In the optical laminate according to the above item

[20] , the pressure-sensitive adhesive sheet and the polarizing film may be in contact with each other.

[22] An image display device according to an embodiment of the present invention includes the optical laminate according to any one of

[19] to

[21] above. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a photocurable pressure-sensitive adhesive sheet suitable for use in image display devices that may be exposed to high-temperature environments. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view schematically illustrating an example of a pressure-sensitive adhesive sheet according to an embodiment of the present invention. [Figure 2] 1A to 1C are schematic diagrams illustrating an example of a method for forming a pressure-sensitive adhesive sheet according to an embodiment of the present invention. [Figure 3]FIG. 1 is a cross-sectional view schematically illustrating an example of an optical laminate according to an embodiment of the present invention. [Figure 4] FIG. 1 is a cross-sectional view schematically illustrating an example of an optical laminate according to an embodiment of the present invention. [Figure 5] FIG. 1 is a cross-sectional view schematically illustrating an example of an optical laminate according to an embodiment of the present invention. [Figure 6] FIG. 1 is a cross-sectional view schematically illustrating an example of an optical laminate according to an embodiment of the present invention. [Figure 7] 1 is a cross-sectional view schematically illustrating an example of an image display device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] [Terminology] In this specification, when the expression "weight" appears, it may be read as "mass," which is the commonly used SI unit for indicating weight, and vice versa.

[0010] In this specification, the expression "(meth)acrylic" means "acrylic and / or methacrylic", the expression "(meth)acrylate" means "acrylate and / or methacrylate", the expression "(meth)allyl" means "allyl and / or methallyl", and the expression "(meth)acrolein" means "acrolein and / or methacrolein".

[0011] The present invention will be described in detail below, but the following description is not intended to limit the present invention to a specific embodiment.

[0012] <<1. Adhesive sheet>> An example of a pressure-sensitive adhesive sheet according to an embodiment of the present invention is shown in Fig. 1. The pressure-sensitive adhesive sheet 1 in Fig. 1 is a pressure-sensitive adhesive sheet formed from a photocurable pressure-sensitive adhesive composition (hereinafter referred to as "pressure-sensitive adhesive composition A") containing a monomer component M. The monomer component M contains a monomer m represented by the following formula (1). X in formula (1) 1 The number of atoms that make up X 2The number of atoms constituting the formula (1) is smaller than the number of atoms constituting the formula (1) and is 4 or less. 3 is a hydrogen atom, or X 2 The monomer m is a monofunctional polymerizable monomer. [ka]

[0013] For the monomer m, the value of the regression equation shown in the following formula (Y) is 8.00 or more. Formula (Y):20.63a-0.6602b+0.2859c+0.2797d+0.2050e+0.1180f+0.000865g-0.8069

[0014] According to the inventors' research, one of the factors that contributes to the deterioration of image quality due to exposure to high-temperature environments is the tendency for the adhesive sheet in the optical laminate to peel off from the adherend (object to be adhesively attached) at high temperatures. Another factor that can contribute to the deterioration of visibility is the foaming of monomers remaining in the adhesive sheet at high temperatures. The adhesive sheet 1 is formed through the photopolymerization of a photocurable adhesive composition A. The presence of monomer m in the photopolymerization system tends to improve the polymerization rate and increase the molecular weight of the polymer formed by polymerization. The increase in molecular weight is believed to contribute to an excellent balance between the stress relaxation properties and cohesive strength of the adhesive sheet 1, and this excellent balance may be suitable for suppressing the above-mentioned peeling at high temperatures. Furthermore, an increase in the polymerization rate can contribute to the suppression of foaming at high temperatures. Note that increasing the amount of photopolymerization initiator or increasing the irradiance of light to increase the cumulative light dose in order to improve the polymerization rate increases the number of radicals that are simultaneously generated, making it difficult to increase the molecular weight. In addition, in a thermosetting pressure-sensitive adhesive composition, the above-mentioned effect due to the presence of monomer m is usually not observed, probably because a large amount of chain transfer of radicals to the solvent occurs.

[0015] The value of the regression equation shown in formula (Y) can be an index of the molecular weight of the polymer formed by polymerization. The value of the regression equation may be 8.20 or more, 8.40 or more, 8.50 or more, 8.70 or more, 8.90 or more, 9.00 or more, 9.20 or more, 9.30 or more, 9.50 or more, 9.70 or more, 9.90 or more, 10.00 or more, 10.20 or more, 10.30 or more, 10.50 or more, 10.70 or more, 10.80 or more, or even 11.00 or more.

[0016] Formula (Y) was created using the following method. One hundred monomers m that can be expressed by formula (1) were randomly selected and combined with a prepolymer consisting of 99 parts by weight of n-butyl acrylate (BA) and 1 part by weight of 4-hydroxyacrylate (4HBA). Polymer sheets for evaluation were prepared by photopolymerization. The weight-average molecular weight (Mw) of the polymers contained in the prepared polymer sheet was measured, and various explanatory variables were created based on the measured Mw values ​​for 24 representative monomers m that evenly covered the data space of Mw measurements. Lasso (least absolute shrinkage and selection operator) regression was then performed. Lasso regression is a linear regression method with an L1 regularization term. Lasso regression was used to extract explanatory variables with high importance, yielding formula (Y). Explanatory variables related to the prepolymer composition were also created, but Lasso regression confirmed that the contribution of these explanatory variables to Mw was low. The coefficient of determination R2 of regression formula (Y) was greater than 0.80.

[0017] a in formula (Y) is the X in the state of being contained in the monomer m, obtained by standard geometry optimization that can be performed by quantum chemical calculations using the density functional theory (DFT) method with B3LYP / 6-31G(d,p) as the basis set. 1The charge (Mulliken charge) calculated by the Mulliken method is shown in Fig. 1. The basis set B3LYP / 6-31G(d,p) is well known in DFT methods for compounds. Standard structural optimization refers to structural optimization calculations that can be performed under the default conditions of software capable of performing quantum chemical calculations. An example of software capable of performing quantum chemical calculations is the general-purpose quantum chemical calculation program Gaussian (e.g., Gaussian 16).

[0018] In formula (Y), b and c are the descriptors VSA_EState5 and VSA_EState7, respectively, included in the RDkit software. b and c are descriptors indicating the contribution of the electrical topological index and molecular surface area of ​​monomer m. The RDkit software is a library of parameters (descriptors) that convert the molecular structure of a compound for cheminformatics processing, and is well known to those skilled in the art for its suitability for building predictive models using machine learning. Note that the "descriptors included in the RDkit software" and "descriptors included in the HSPiP software" described herein may be descriptors included in the new software if the names of the RDkit software or HSPiP software are changed due to a version upgrade or integration, or may be descriptors included in software other than the RDkit software or HSPiP software, as long as they are determined to represent equivalent features in the chemical structure.

[0019] In formula (Y), d is the descriptor Num Aliphatic Heterocycles included in the RDkit software, which indicates the number of aliphatic heterocycles contained in monomer m.

[0020] In formula (Y), e is the descriptor δD implemented in the HSPiP software. e is a descriptor indicating the dispersion term δD in the Hansen solubility parameter. The Hansen solubility parameter is a solubility parameter introduced by Hildebrand, divided into three components: the dispersion term δD, the polarization term δP, and the hydrogen bonding term δH. The dispersion term δD indicates the energy derived from intermolecular dispersion forces. Details of the Hansen solubility parameter are disclosed in "Hansen Solubility Parameters; A Users Handbook" (CRC Press, 2007). The HSPiP software is well known to those skilled in the art as software used to calculate the Hansen solubility parameter.

[0021] In formula (Y), f is the descriptor PEOE_VSA1 included in the RDkit software, which indicates the electronegativity and molecular surface area contribution of the monomer m.

[0022] In formula (Y), g is the descriptor AntB included in the HSPiP software. g is a descriptor indicating the constant B in the Antouine formula of monomer m.

[0023] The value of a in formula (Y) may be 0.08 or more, 0.09 or more, 0.10 or more, 0.11 or more, 0.12 or more, 0.13 or more, or even 0.14 or more. The upper limit of the value of a is, for example, 0.30 or less, and may be 0.25 or less, 0.20 or less, 0.19 or less, 0.18 or less, 0.17 or less, 0.16 or less, 0.15 or less, 0.14 or less, 0.13 or less, 0.12 or less, or even 0.11 or less.

[0024] The value of b in formula (Y) is, for example, -3.00 or more and 0.50 or less. The value of b may be 0 or less, -0.10 or less, -0.20 or less, or even -0.30 or less. The value of b may be -2.50 or more, or -2.00 or more.

[0025] The value of c in formula (Y) may be 1.10 or more, 1.15 or more, 1.20 or more, 1.30 or more, 1.40 or more, 1.50 or more, 1.60 or more, 1.70 or more, 1.80 or more, 1.90 or more, 2.00 or more, 2.10 or more, 2.20 or more, 2.30 or more, 2.40 or more, or even 2.50 or more. The upper limit of the value of c is, for example, 6.00 or less, and may be 5.90 or less, 5.80 or less, 5.70 or less, 5.60 or less, 5.50 or less, or even 5.40 or less.

[0026] The value of d in formula (Y) may be 0 or may be equal to or greater than 1. The value of d may be equal to or greater than 1, in other words, the monomer m may have an aliphatic heterocycle in the side chain.

[0027] The value of e in formula (Y) is, for example, 13.00 or more and 25.00 or less. The upper limit of the value of e may be 24.00 or less, 23.00 or less, 22.00 or less, 21.00 or less, 20.00 or less, 19.00 or less, 18.00 or less, or even 17.50 or less. The lower limit of the value of e may be 14.00 or more, 15.00 or more, 16.00 or more, 16.20 or more, 16.40 or more, 16.50 or more, 16.70 or more, 16.80 or more, or even 16.90 or more.

[0028] The value of f in formula (Y) is, for example, 4.00 or more and 20.00 or less. The upper limit of the value of f may be 19.00 or less. The lower limit of the value of f may be 5.00 or more, 6.00 or more, 7.00 or more, 8.00 or more, or even 9.00 or more.

[0029] The value of g in formula (Y) is, for example, 1500 or more, and may be 1525 or more, 1550 or more, 1575 or more, 1600 or more, 1625 or more, 1650 or more, 1675 or more, 1680 or more, 1685 or more, 1690 or more, or even 1695 or more. The upper limit of the value of g is, for example, 2500 or less, and may be 2450 or less, 2400 or less, 2375 or less, or even 2350 or less.

[0030] The value of a in formula (Y) may be 0.10 or more, and the value of e may be 16.00 or more.

[0031] <1-1. Pressure-sensitive adhesive composition A> The pressure-sensitive adhesive composition A is a photocurable pressure-sensitive adhesive composition that forms a pressure-sensitive adhesive sheet by irradiation with active energy rays. The photocurable type is particularly preferable in terms of environmental protection and sustainability, since it can reduce the amount of energy required to form a pressure-sensitive adhesive sheet compared to a thermosetting type that forms a pressure-sensitive adhesive sheet mainly by using heat.

[0032] <1-1-a. Monomer component M> [1-1-a1.Monomer m] The pressure-sensitive adhesive composition A contains a monomer component M. The monomer component M contains a monomer m. The monomer m is a monomer represented by the following formula (1). X in formula (1) 1 The number of atoms that make up X 2 is smaller than the number of atoms that make up X and is 4 or less. 3 is a hydrogen atom, or X 2 It bonds to form a ring structure. [ka]

[0033] X in equation (1) 1 The lower limit of the number of atoms that make up X is 1 or more. 1 The number of atoms constituting the group may be 3 or less, 2 or less, or 1.

[0034] X 1 The atoms constituting the group may be at least one selected from the group consisting of hydrogen atoms, carbon atoms, and oxygen atoms, or may be at least one selected from the group consisting of hydrogen atoms and carbon atoms.

[0035] X 1may be a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, or may be a hydrogen atom, a methyl group, or an ethyl group, or may be a hydrogen atom or a methyl group. The alkyl group may be linear or branched.

[0036] X in equation (1) 2 The number of atoms constituting X may be 3 or more, 4 or more, 5 or more, 6 or more, 7 or more, 8 or more, or even 9 or more. 2 The upper limit of the number of atoms constituting the group is, for example, 70 or less.

[0037] X 2 The atoms constituting X may be at least one selected from the group consisting of hydrogen atoms, carbon atoms, oxygen atoms, and nitrogen atoms, or may be at least one selected from the group consisting of hydrogen atoms, carbon atoms, and oxygen atoms. 2 may contain a nitrogen atom or may not contain a nitrogen atom. 2 An example of the monomer m includes an amide structure. In other words, the monomer m may be a vinyl amide monomer.

[0038] X 2 may contain a ring structure or may be composed of a ring structure. The ring structure may be an aliphatic ring, a heterocyclic ring, or an aliphatic heterocyclic ring. In other words, X 2 may contain an aliphatic heterocycle. The heteroatom constituting the heterocycle may be at least one selected from the group consisting of an oxygen atom, a nitrogen atom, and a sulfur atom, or at least one selected from the group consisting of an oxygen atom and a nitrogen atom, or may be an oxygen atom. The heterocycle may contain only an oxygen atom as a heteroatom. The heterocycle may not contain a nitrogen atom. The number of heteroatoms contained in the heterocycle may be 1 or 2, or may be 1.

[0039] X 2 The aliphatic heterocycle that may be contained in X may not contain a nitrogen atom. An example of an aliphatic heterocycle that does not contain a nitrogen atom is a cyclic ether. 2The aliphatic heterocycle that may be contained may be a cyclic ether.

[0040] X 2 The ring structure that may be contained in X, for example, an aliphatic heterocycle, may be a 4- or more-membered ring, a 5- or more-membered ring, or even a 6- or more-membered ring. 2 The aliphatic heterocycle that may be contained may be a five- or more-membered ring.

[0041] X 2 The ring structure may have a substituent. Examples of the substituent include an alkyl group having 1 to 6 carbon atoms, a hydroxy group, a nitro group, an amino group, a sulfo group, an aldehyde group, a carboxy group, and a carbonyl group. The alkyl group may be linear or branched. More specific examples of the substituent include a methyl group, an ethyl group, an n-propyl group, and an isopropyl group.

[0042] X 2 is not limited to the above example.

[0043] X in equation (1) 3 is a hydrogen atom, or X 2 It bonds to form a ring structure. X 2 and X 3 The ring structure formed by bonding with X may contain the carbon-carbon double bond (—C═C—) shown in formula (1) as part of the ring structure. 2 and X 3 The ring structure formed by the bond with may contain a carboxylic acid anhydride structure. An example of a carboxylic acid anhydride structure is a maleic anhydride structure.

[0044] X 3 may be a hydrogen atom.

[0045] Monomer m may be a (meth)acrylate monomer or an acrylate monomer. X of monomer m which is a (meth)acrylate monomer 2 contains a carboxylic acid ester group (-C(=O)O-).

[0046] Monomer m may be a monomer represented by the following formula (2): X in formula (2) 4 is a cyclic ether group. L is a single bond, an alkylene group, a carboxylic acid ester group, or a group in which an alkylene group and a carboxylic acid ester group are combined. [ka]

[0047] The cyclic ether group may have a substituent bonded to a carbon atom constituting the ring. Examples of the substituent that the cyclic ether group may have include X 2 are the same as the examples of the substituents that the ring structure may have.

[0048] The cyclic ether group may be a four- or more-membered ring, or even a five- or more-membered ring.

[0049] X 4 Examples of cyclic ether groups that can be are oxolane, dioxolane, and dioxane groups, where X 4 The cyclic ether groups that can be are not limited to the above examples.

[0050] The number of carbon atoms in the alkylene group that can be L is, for example, 1 to 12, and may be 1 to 10, 1 to 9, 1 to 8, 1 to 7, or even 1 to 6. The alkylene group may be a methylene group or an ethylene group, or may be a methylene group.

[0051] An example of a group in which an alkylene group and a carboxylic acid ester group are combined, which can be L, is a group shown in the following formula (3): n in formula (3) is, for example, 1 to 6, and may be 1 to 5, 1 to 4, 1 to 3, or even 1 or 2. [ka]

[0052] The molecular weight of monomer m may be 500 or less, 450 or less, 400 or less, 380 or less, 360 or less, 350 or less, 340 or less, 325 or less, 300 or less, 275 or less, 250 or less, 225 or less, or even 200 or less. The lower limit of the molecular weight of monomer m is, for example, 40 or more.

[0053] Monomer m is not limited to the above specific examples, as long as it is a monomer represented by the above formula (1) and satisfies the regression equation value represented by formula (Y) of 8.00 or more.

[0054] The content of monomer m in monomer component M is, for example, 1 to 70% by weight. The lower limit of the content may be 1.5% by weight or more, 2% by weight or more, 2.5% by weight or more, 3% by weight or more, 3.5% by weight or more, 4% by weight or more, 4.5% by weight or more, 5% by weight or more, 5.5% by weight or more, 6% by weight or more, 6.5% by weight or more, 7% by weight or more, 7.5% by weight or more, 8% by weight or more, 8.5% by weight or more, 9% by weight or more, 9.5% by weight or more, 10% by weight or more, 11% by weight or more, 12% by weight or more, or even 13% by weight or more. The upper limit of the content may be 65% by weight or less, 60% by weight or less, 55% by weight or less, 50% by weight or less, 45% by weight or less, 40% by weight or less, 35% by weight or less, 30% by weight or less, 25% by weight or less, 20% by weight or less, 18% by weight or less, 16% by weight or less, or even 15% by weight or less. The content of the monomer m may be 4 to 20% by weight.

[0055] When the total amount of monomers other than monomer m contained in monomer component M is taken as 100 parts by weight, the content of monomer m in monomer component M may be, for example, 1.5 parts by weight or more, 2 parts by weight or more, 2.5 parts by weight or more, 3 parts by weight or more, 3.5 parts by weight or more, 4 parts by weight or more, 4.5 parts by weight or more, 5 parts by weight or more, 5.5 parts by weight or more, 6 parts by weight or more, 6.5 parts by weight or more, 7 parts by weight or more, 7.5 parts by weight or more, 8 parts by weight or more, 8.5 parts by weight or more, 9 parts by weight or more, 9.5 parts by weight or more, 10 parts by weight or more, 11 parts by weight or more, 12 parts by weight or more, 13 parts by weight or more, 14 parts by weight or more, or even 15 parts by weight or more. The upper limit of the content may be 250 parts by weight or less, 225 parts by weight or less, 200 parts by weight or less, 175 parts by weight or less, 150 parts by weight or less, 125 parts by weight or less, 100 parts by weight or less, 90 parts by weight or less, 80 parts by weight or less, 70 parts by weight or less, 60 parts by weight or less, 50 parts by weight or less, 40 parts by weight or less, 35 parts by weight or less, 30 parts by weight or less, 25 parts by weight or less, 20 parts by weight or less, or even 18 parts by weight or less. The content of monomer m may be 4 to 25 parts by weight when the total amount of monomers other than monomer m contained in monomer component M is 100 parts by weight.

[0056] [1-1-a2. Other Monomers] Monomer component M may contain other monomers in addition to monomer m. An example of such other monomers is a hydroxyl group-containing monomer. The hydroxyl group-containing monomer has at least one hydroxyl group and at least one ethylenically unsaturated group in one molecule. Monomer component M may contain one or more hydroxyl group-containing monomers. The hydroxyl group-containing monomers as other monomers exclude those corresponding to monomer m.

[0057] Examples of ethylenically unsaturated groups are (meth)acryloyl, vinyl, and (meth)allyl groups. From the viewpoint of polymerization reactivity, (meth)acryloyl groups are preferred, and from the viewpoint of flexibility and adhesiveness, acryloyl groups are more preferred. The same applies to the ethylenically unsaturated groups described below. The hydroxyl group-containing monomer may be a (meth)acrylic monomer.

[0058] Examples of hydroxyl group-containing monomers include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, and (4-hydroxymethylcyclohexyl)-methyl acrylate. The hydroxyl group-containing monomer is preferably 4-hydroxybutyl (meth)acrylate. The content of the hydroxyl group-containing monomer in the monomer component M may be, for example, 25% by weight or less, 20% by weight or less, 15% by weight or less, 12% by weight or less, 10% by weight or less, 8% by weight or less, 7% by weight or less, 6% by weight or less, 5% by weight or less, 4% by weight or less, 3% by weight or less, 2% by weight or less, or even 1% by weight or less. The lower limit of the content is, for example, 0.01% by weight or more, and may be 0.1% by weight or more, 0.5% by weight or more, or even 1% by weight or more. Monomer component M may be substantially free of hydroxyl group-containing monomers.

[0059] Another example of the other monomer is a (meth)acrylic acid alkyl ester having an alkyl group of 1 to 20 carbon atoms on the side chain. The number of carbon atoms in the alkyl group may be 7 or less, 6 or less, 5 or less, or even 4 or less. The alkyl group may be linear or branched. The monomer component M may contain one or more types of (meth)acrylic acid alkyl ester. The (meth)acrylic acid alkyl ester as the other monomer excludes those corresponding to monomer m.

[0060] Examples of (meth)acrylic acid alkyl esters include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, isobutyl (meth)acrylate, n-pentyl (meth)acrylate, isopentyl (meth)acrylate, n-hexyl (meth)acrylate, isohexyl (meth)acrylate, isoheptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, n-nonyl (meth)acrylate, isononyl (meth)acrylate, n-decyl (meth)acrylate, isodecyl (meth)acrylate, n-dodecyl (meth)acrylate (lauryl (meth)acrylate), n-tridecyl (meth)acrylate, n-tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, and octadecyl (meth)acrylate. The (meth)acrylic acid alkyl ester may be n-butyl (meth)acrylate.

[0061] The content of the (meth)acrylic acid alkyl ester in the monomer component M is, for example, 25% by weight or more, and may be 30% by weight or more, 35% by weight or more, 40% by weight or more, 45% by weight or more, 50% by weight or more, 55% by weight or more, 60% by weight or more, 65% by weight or more, 70% by weight or more, 75% by weight or more, 80% by weight or more, or even 85% by weight or more. The upper limit of the content is, for example, 98% by weight or less, and may be 97% by weight or less, 96% by weight or less, 95% by weight or less, 93% by weight or less, 91% by weight or less, 90% by weight or less, 88% by weight or less, 86% by weight or less, or even 85% by weight or less. The monomer component M may be substantially free of a (meth)acrylic acid alkyl ester.

[0062] The monomer component M may contain the monomer m, the above-mentioned (meth)acrylic acid alkyl ester, and a hydroxyl group-containing monomer.

[0063] Another example of the other monomer is a carboxyl group-containing monomer. The carboxyl group-containing monomer that can be contained in the monomer component M has at least one carboxyl group and at least one ethylenically unsaturated group in one molecule. The carboxyl group-containing monomer may be a (meth)acrylic monomer. The monomer component M may contain one or more carboxyl group-containing monomers. The carboxyl group-containing monomers as the other monomers exclude those that correspond to the monomer m.

[0064] Examples of carboxyl group-containing monomers are (meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid and crotonic acid.

[0065] The content of the carboxyl group-containing monomer in the monomer component M is, for example, 10% by weight or less, and may be 7% by weight or less, 5% by weight or less, 3% by weight or less, 1% by weight or less, 0.5% by weight or less, 0.3% by weight or less, 0.2% by weight or less, 0.15% by weight or less, or even 0.12% by weight or less. The lower limit of the content is, for example, 0.05% by weight or more, and may be 0.1% by weight or more, 0.3% by weight or more, or even 0.5% by weight or more. Preferably, the monomer component M is substantially free of a carboxyl group-containing monomer. In this specification, "substantially free" means that the content is less than 0.1% by weight, preferably less than 0.05% by weight.

[0066] The pressure-sensitive adhesive sheet 1 includes a polymer having structural units formed by polymerization of monomers contained in the monomer component M. The weight-average molecular weight (Mw) of the polymer may be 750,000 or more, 800,000 or more, 850,000 or more, 900,000 or more, 930,000 or more, 950,000 or more, 980,000 or more, or even 1,000,000 or more. The upper limit of Mw is, for example, 3,000,000 or less, and may be 2,500,000 or less, 2,200,000 or less, 2,000,000 or less, 1,700,000 or less, or even 1,500,000 or less. The Mw of the polymer can be measured by GPC (gel permeation chromatography) and calculated in polystyrene equivalent terms.

[0067] The polymerization rate of the monomer component M in the pressure-sensitive adhesive sheet 1 is preferably 90% or more. The polymerization rate may be 93% or more, 95% or more, 96% or more, 96.5% or more, 97% or more, 98% or more, or even 98.5% or more.

[0068] In the pressure-sensitive adhesive sheet 1, both the Mw of the polymer having structural units formed by polymerization of the monomers contained in the monomer component M and the polymerization rate of the monomer component M may be within the ranges exemplified above.

[0069] <1-1-b. Partially polymerized product> The pressure-sensitive adhesive composition A may contain a partial polymer of the monomer component M. The partial polymer may be either a homopolymer or a copolymer. The partial polymer can contribute to the stable formation of a coating layer, which will be described later, by appropriately increasing the viscosity of the pressure-sensitive adhesive composition A. The pressure-sensitive adhesive composition A does not necessarily contain a partial polymer of the monomer component M.

[0070] <1-1-c. Photopolymerization initiator> The pressure-sensitive adhesive composition A usually contains a photopolymerization initiator. The photopolymerization initiator may be a photoradical generator that generates radicals when exposed to visible light and / or ultraviolet light with a wavelength shorter than 450 nm.

[0071] Examples of photopolymerization initiators include benzoin ethers such as benzoin methyl ether, benzoin isopropyl ether, and benzil dimethyl ketal; substituted benzoin ethers such as anisole methyl ether; substituted acetophenones such as 2,2-diethoxyacetophenone and 2,2-dimethoxy-2-phenylacetophenone; α-hydroxyalkylphenones such as 1-hydroxycyclohexyl-phenyl ketone; substituted alpha-ketols such as 2-methyl-2-hydroxypropiophenone; aromatic sulfonyl chlorides such as 2-naphthalenesulfonyl chloride; photoactive oximes such as 1-phenyl-1,1-propanedione-2-(o-ethoxycarbonyl)-oxime; and benzophenone compounds such as benzophenone, benzoylbenzoic acid, methyl benzoylbenzoate, 4-phenylbenzophenone, hydroxybenzophenone, acrylated benzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, and 3,3',4,4'-tetra(t-butylperoxycarbonyl)benzophenone. Thioxanthone compounds such as thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthioxanthone, and 2,4-diethylthioxanthone; 2,4,6-trichloro-s-triazine, 2-phenyl-4,6-bis(trichloromethyl)-s-triazine, 2-(p-methoxyphenyl)-4,6-bis(trichloromethyl)-s-triazine, and 2-(p-tolyl)-4,6-bis(trichloromethyl)-s-triazine triazine-based compounds such as 2-piperonyl-4,6-bis(trichloromethyl)-s-triazine, 2,4-bis(trichloromethyl)-6-styryl-s-triazine, 2-(naphth-1-yl)-4,6-bis(trichloromethyl)-s-triazine, 2-(4-methoxy-naphth-1-yl)-4,6-bis(trichloromethyl)-s-triazine, 2,4-trichloromethyl-(piperonyl)-6-triazine, and 2,4-trichloromethyl-(4'-methoxystyryl)-6-triazine;Oxime ester compounds such as 1,2-octanedione, 1-[4-(phenylthio)-, 2-(O-benzoyloxime)], O-(acetyl)-N-(1-phenyl-2-oxo-2-(4'-methoxy-naphthyl)ethylidene)hydroxylamine; phosphine compounds such as bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide and 2,4,6-trimethylbenzoyldiphenylphosphine oxide; quinone compounds such as 9,10-phenanthrenequinone, camphorquinone, and ethylanthraquinone; borate compounds; carbazole compounds; imidazole compounds; and titanocene compounds. The pressure-sensitive adhesive composition A may contain one or more photopolymerization initiators.

[0072] Specific examples of the photopolymerization initiator include 2,2-dimethoxy-1,2-diphenylethan-1-one (Omnirad651, manufactured by IGM Resins), bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (Omnirad819, manufactured by IGM Resins), 1-hydroxycyclohexyl phenyl ketone (Omnirad184, manufactured by IGM Resins), and 2-hydroxy-1-(4-(4-(2-hydroxy-2-methylpropionyl)benzyl)phenyl)2-methylpropan-1-one (Omnirad127D, manufactured by IGM Resins). However, the photopolymerization initiator is not limited to the above examples.

[0073] The content of the photopolymerization initiator in the pressure-sensitive adhesive composition A is, for example, 0.02 to 10 parts by weight, or may be 0.05 to 5 parts by weight, 0.1 to 3 parts by weight, or even 0.2 to 2 parts by weight, relative to 100 parts by weight of the monomer component M.

[0074] <1-1-d. Crosslinking Agents> The pressure-sensitive adhesive composition A may contain a crosslinking agent. An example of the crosslinking agent is a polyfunctional monomer having two or more polymerizable functional groups in one molecule. The polyfunctional monomer may be a (meth)acrylic monomer. Examples of the polyfunctional monomer are a monomer having two or more C=C bonds in one molecule, and a monomer having one or more C=C bonds and one or more polymerizable functional groups such as epoxy groups, aziridine groups, oxazoline groups, hydrazine groups, methylol groups, etc. in one molecule. The polyfunctional monomer is preferably a monomer having two or more C=C bonds in one molecule.

[0075] Examples of polyfunctional monomers include (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,2-ethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol diacrylate (N Polyfunctional acrylates (such as ester compounds of polyhydric alcohols and (meth)acrylic acid) such as dimethyl acrylate (DDA), 1,12-dodecanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, and tetramethylolmethane tri(meth)acrylate; allyl (meth)acrylate, vinyl (meth)acrylate, divinylbenzene, epoxy acrylate, polyester acrylate, urethane acrylate, butyl di(meth)acrylate, and hexyl di(meth)acrylate. The polyfunctional monomer is preferably a polyfunctional acrylate, more preferably trimethylolpropane tri(meth)acrylate, hexanediol di(meth)acrylate, or dipentaerythritol hexa(meth)acrylate.

[0076] The content of the crosslinking agent in the pressure-sensitive adhesive composition A is, for example, 5 parts by weight or less, and may be 4 parts by weight or less, 3 parts by weight or less, 2 parts by weight or less, 1 part by weight or less, 0.5 parts by weight or less, 0.4 parts by weight or less, 0.3 parts by weight or less, or even 0.2 parts by weight or less, relative to 100 parts by weight of the monomer component M. The lower limit of the content may be, for example, 0.01 parts by weight or more, 0.02 parts by weight or more, 0.03 parts by weight or more, 0.04 parts by weight or more, or even 0.05 parts by weight or more.

[0077] <1-1-e. Additives> The pressure-sensitive adhesive composition A may contain an additive, such as a silane coupling agent. Specific examples of the silane coupling agent include epoxy group-containing silane coupling agents such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; amino group-containing silane coupling agents such as 3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl-N-(1,3-dimethylbutylidene)propylamine, and N-phenyl-γ-aminopropyltrimethoxysilane; (meth)acrylic group-containing silane coupling agents such as 3-acryloxypropyltrimethoxysilane and 3-methacryloxypropyltriethoxysilane; and isocyanate group-containing silane coupling agents such as 3-isocyanatepropyltriethoxysilane.

[0078] The content of the silane coupling agent in the pressure-sensitive adhesive composition A is, for example, 5 parts by weight or less, and may be 3 parts by weight or less, 1 part by weight or less, 0.8 parts by weight or less, 0.5 parts by weight or less, 0.4 parts by weight or less, 0.3 parts by weight or less, 0.2 parts by weight or less, or even 0.1 parts by weight or less, relative to 100 parts by weight of the monomer component M. The lower limit of the content may be, for example, 0.01 parts by weight or more, or even 0.05 parts by weight or more. The pressure-sensitive adhesive composition A may not contain a silane coupling agent.

[0079] Another example of an additive is an antioxidant, examples of which include phenolic antioxidants, hindered phenolic antioxidants, amine antioxidants, and phosphite antioxidants.

[0080] Examples of the phenolic antioxidant include monophenolic antioxidants, bisphenolic antioxidants, and polymeric phenolic antioxidants. Examples of the monophenolic antioxidant include 2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-4-ethylphenol, and stearin-β-(3,5-di-t-butyl-4-hydroxyphenyl)propionate. Examples of the bisphenol antioxidant are 2,2'-methylenebis(4-methyl-6-t-butylphenol), 2,2'-methylenebis(4-ethyl-6-t-butylphenol), 4,4'-thiobis(3-methyl-6-t-butylphenol), 4,4'-butylidenebis(3-methyl-6-t-butylphenol), and 3,9-bis[1,1-dimethyl-2-[β-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy]ethyl]2,4,8,10-tetraoxaspiro[5,5]undecane. Examples of polymeric phenolic antioxidants include 1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane, 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene, tetrakis-[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane, bis[3,3'-bis-(4'-hydroxy-3'-t-butylphenyl)butyric acid]glycol ester, 1,3,5-tris(3',5'-di-t-butyl-4'-hydroxybenzyl)-S-triazine-2,4,6-(1H,3H,5H)trione, and tocopherol.

[0081] The hindered phenol-based antioxidant may have a structure in which a tertiary butyl group is bonded to at least one carbon atom adjacent to a carbon atom on an aromatic ring to which a phenolic OH group is bonded. Examples of hindered phenolic antioxidants include dibutylhydroxytoluene (BHT); and Irganox1010, Irganox1010FF, Irganox1035, Irganox1035FF, Irganox1076, Irganox1076FD, Irganox1076DWJ, Irganox1098, Irganox1135, Irganox1330, Irganox1726, Irganox1425WL, Irganox1520L, Irganox245, Irganox245FF, Irganox259, Irganox3114, Irganox565, and Irganox295 (all of which are trade names manufactured by BASF).

[0082] The amine antioxidant is preferably a hindered amine antioxidant. The hindered amine antioxidant may have at least one hindered piperazine group in one molecule. Examples of the hindered amine antioxidant include ADK STAB LA-63, ADK STAB LA-63P, ADK STAB LA-52, and ADK STAB LA-57 (all of which are trade names, manufactured by ADEKA Corporation).

[0083] Examples of the phosphite antioxidants are triphenyl phosphite, diphenyl isodecyl phosphite, and phenyl diisodecyl phosphite; and Adeka STAB 2112, Adeka STAB 2112RG, Adeka STAB 1178, and Adeka STAB 3010 (all of which are trade names, manufactured by ADEKA Corporation).

[0084] The content of the antioxidant in the pressure-sensitive adhesive composition A is, for example, 5 parts by weight or less, and may be 3 parts by weight or less, 1 part by weight or less, 0.8 parts by weight or less, or even 0.5 parts by weight or less, relative to 100 parts by weight of the monomer component M. The lower limit of the content may be, for example, 0.01 parts by weight or more, or even 0.05 parts by weight or more. The pressure-sensitive adhesive composition A may not contain an antioxidant.

[0085] The PSA composition A may contain additives other than those described above. Examples of the additives include a chain transfer agent, a viscosity modifier, a tackifier, a plasticizer, a softener, an antioxidant, a filler, a colorant, a surfactant, and an antistatic agent.

[0086] <1-1-f. Solvents> The content of the solvent in the PSA composition A is, for example, 5 wt % or less, and may be 4 wt % or less, 3 wt % or less, 2 wt % or less, 1 wt % or less, or even 0.5 wt % or less. The PSA composition A may be substantially free of solvent. "Substantially free of solvent" means that solvents derived from additives and the like are allowed at a content of, for example, 0.1 wt % or less, preferably 0.05 wt % or less, and more preferably 0.01 wt % or less.

[0087] <1-1-g. Physical properties> The viscosity of the pressure-sensitive adhesive composition A is preferably 5 to 150 poise at 25° C. The pressure-sensitive adhesive composition A having a viscosity in the above range is particularly suitable for forming a coating layer, which will be described later.

[0088] ≪1-2. Characteristics of adhesive sheets≫ The thickness of the pressure-sensitive adhesive sheet 1 is, for example, 500 μm or less, and may be 250 μm or less, 150 μm or less, 100 μm or less, 50 μm or less, 30 μm or less, 25 μm or less, or even 20 μm or less. The lower limit of the thickness of the pressure-sensitive adhesive sheet 1 is, for example, 2 μm or more, and may be 3 μm or more, 4 μm or more, or 5 μm or more. The thickness of the pressure-sensitive adhesive sheet 1 may be 5 to 30 μm.

[0089] The gel fraction of the pressure-sensitive adhesive sheet 1 is, for example, 50% or more, and may be 75% or more, 80% or more, 85% or more, or even 90% or more.

[0090] The solvent content in the pressure-sensitive adhesive sheet 1 is, for example, 5% by weight or less, and may be 4% by weight or less, 3% by weight or less, 2% by weight or less, 1% by weight or less, or even 0.5% by weight or less. The pressure-sensitive adhesive sheet 1 may be substantially free of solvent.

[0091] The pressure-sensitive adhesive sheet 1 may be used to attach an optical substrate, or may be used to attach an optical substrate including a polarizing film. The object to which the optical substrate is attached is, for example, an image display panel. However, the use of the optical substrate and the object to which the optical substrate is attached are not limited to the above examples.

[0092] ≪1-3. Manufacturing method of adhesive sheets≫ The PSA sheet 1 can be formed from the PSA composition A, for example, by irradiating a first laminate 30 comprising, in this order, a base sheet 31, a coating layer 32 containing the PSA composition A, and a release liner 33 with active energy rays 34 (see FIG. 2 ). The coating layer 32 is irradiated with active energy rays 34 and cured to form the PSA sheet 1. When the PSA sheet 1 is formed by irradiating one side of the coating layer 32 with active energy rays 34, the irradiation is typically carried out from the side of the base sheet 31. In this case, the active energy rays 34 penetrate the base sheet 31 to reach the coating layer 32 and cure the coating layer 32. However, the irradiation with active energy rays 34 may also be carried out from the side of the release liner 33. When the PSA sheet 1 is formed by irradiating both sides of the coating layer 32 with active energy rays 34, the irradiation is carried out from both the side of the release liner 33 and the side of the base sheet 31.

[0093] The formed pressure-sensitive adhesive sheet 1 is sandwiched between the base sheet 31 and the release liner 33 until the release liner 33 is peeled off, and constitutes a part of the second laminate 37. By peeling the release liner 33 from the second laminate 37, a third laminate 35 including the base sheet 31 and the pressure-sensitive adhesive sheet 1 is obtained. In the third laminate 35, the surface of the pressure-sensitive adhesive sheet 1 is exposed to the outside. An optical substrate can be laminated onto the exposed surface of the pressure-sensitive adhesive sheet 1 directly or via another layer.

[0094] Examples of active energy rays 34 include ionizing radiation such as α rays, β rays, γ rays, neutron rays, and electron beams, as well as visible light and ultraviolet light. The active energy rays 34 are preferably visible light or ultraviolet light having a wavelength shorter than 450 nm, and more preferably ultraviolet light. Hereinafter, visible light and ultraviolet light will be collectively referred to as "light."

[0095] The light may include light having a wavelength in the same region as the absorption wavelength of the photopolymerization initiator contained in the pressure-sensitive adhesive composition A. Light having a wavelength of 300 nm or less may be irradiated by filtering out short-wavelength light using a filter or the like. Filtering out short-wavelength light is suitable for suppressing deterioration of the base sheet 31 and / or release liner 33 due to the active energy rays 34. The light source 38 for the active energy rays 34 is, for example, a light irradiation device equipped with an ultraviolet irradiation lamp. Examples of ultraviolet irradiation lamps include ultraviolet LEDs, low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halide lamps, xenon lamps, microwave-excited mercury lamps, black light lamps, chemical lamps, germicidal lamps, low-pressure discharge mercury lamps, and excimer lasers. Two or more ultraviolet irradiation lamps may be combined.

[0096] The illuminance of the light irradiated onto the first laminate 30 (specifically, the coating layer 32) is, for example, 2.0 to 30 mW / cm 2 The illuminance is 2.5mW / cm 2 More than 3.0mW / cm 2 More than 3.5mW / cm 2 More than 4.0mW / cm 2 More than 5.0mW / cm 2 More than 6.0mW / cm 2 More than 7.0mW / cm 2 More than 8.0mW / cm 2 More than 9.0mW / cm 2 or more, and even 10mW / cm 2 The upper limit of the illuminance may be, for example, 25 mW / cm 2 less than 20 mW / cm 2 It may be the following:

[0097] The time for irradiating the first laminate 30 (specifically, the coating layer 32) with light is, for example, 10 to 1000 seconds, and may be 60 seconds or more, 100 seconds or more, 150 seconds or more, or even 200 seconds or more. The upper limit of the time is, for example, 800 seconds or less, and may be 600 seconds or less, 500 seconds or less, 400 seconds or less, 300 seconds or less, or even 250 seconds or less. The light irradiation may be continuous or intermittent.

[0098] The integrated amount of light on the first laminate 30 (specifically, the coating layer 32) is, for example, 25 mJ / cm 2 2 or more, 100 mJ / cm 2 More than 500mJ / cm 2 More than 1000mJ / cm 2 More than 2000mJ / cm 2 More than 2500mJ / cm 2 More than 3000mJ / cm 2 More than 5000mJ / cm 2 More than 7500mJ / cm 2 or more, even 10,000 mJ / cm 2 The upper limit of the cumulative light amount is not particularly limited, and may be, for example, 30,000 mJ / cm 2 or more. 2 Less than 25,000 mJ / cm 2 Below, 20000mJ / cm 2 Below that, even 18000mJ / cm 2 It may be the following:

[0099] The light may be irradiated to the first laminate 30 in multiple stages. The illuminance and / or the integrated amount of light in each stage may be the same or different. Furthermore, the light source in each stage may be the same or different.

[0100] An example of the substrate of the release liner 33 (hereinafter referred to as the "liner substrate") is a resin film. Examples of resins that can be contained in the liner substrate include polyesters such as polyethylene terephthalate and polyethylene naphthalate, acetate resins, polyethersulfone, polycarbonate, polyamide, polyimide, polyolefin, (meth)acrylic resins, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyvinyl alcohol, polyarylate, and polyphenylene sulfide. The resin is preferably a polyester such as polyethylene terephthalate.

[0101] The release liner 33 may include a layer other than the liner substrate. The release liner 33 may include a release layer. The release liner 33 includes, for example, a liner substrate and a release layer formed on one surface of the liner substrate. This release liner 33 can be used so that the release layer faces the coating layer 32. The release layer is typically a cured layer of a release agent composition containing a release agent. Various release agents can be used as the release agent, such as silicone-based release agents, fluorine-based release agents, long-chain alkyl-based release agents, fatty acid amide-based release agents, and silica powder.

[0102] The release liner 33 may be in the form of a sheet or a continuous piece.

[0103] An example of the base sheet 31 is a resin film. Examples of the resin contained in the base sheet 31 are the same as the examples of the resin that can be contained in the liner base material.

[0104] The thickness of the base sheet 31 is, for example, 10 to 200 μm, and may be 25 to 150 μm.

[0105] The base sheet 31 may have a release layer on the surface on the side of the coating layer 32. Examples of the release layer that may be provided on the base sheet 31 are the same as the examples of the release layer that may be provided on the release liner 33. Both the release liner 33 and the base sheet 31 may have a release layer.

[0106] For base sheet 31 , a sheet having a greater peel strength from adhesive sheet 1 than release liner 33 can usually be selected.

[0107] The base sheet 31 may be in the form of a sheet or a continuous sheet.

[0108] The first laminate 30 can be formed, for example, by forming a coating layer 32 on a base sheet 31 (or a release liner 33), and then placing the release liner 33 (or base sheet 31) on the formed coating layer 32. Alternatively, the first laminate 30 may be formed by applying the PSA composition A in a pouring manner into the space between the base sheet 31 and the release liner 33, which are held at a predetermined distance so that their main surfaces face each other.

[0109] The coating layer 32 can be formed by various coating methods such as roll coating, kiss roll coating, gravure coating, reverse coating, roll brush, spray coating, dip roll coating, bar coating, knife coating, air knife coating, curtain coating, lip coating, and die coating.

[0110] The thickness of coating layer 32 can be adjusted depending on the desired thickness of PSA sheet 1, and may be, for example, 500 μm or less, 250 μm or less, 150 μm or less, 100 μm or less, 50 μm or less, 30 μm or less, 25 μm or less, or even 20 μm or less. The lower limit of the thickness of coating layer 32 is, for example, 2 μm or more, and may be 3 μm or more, 4 μm or more, or even 5 μm or more.

[0111] The first laminate 30 may include a long base sheet 31, a long coating layer 32, and a long release liner 33, in other words, may be long. The long first laminate 30 can be obtained, for example, by forming the coating layer 32 between the base sheet 31 and the release liner 33 while conveying them after they have been unwound from a roll.

[0112] ≪≪2. Optical laminate≫≫ An example of an optical laminate according to an embodiment of the present invention is shown in Figure 3. The optical laminate 20A in Figure 3 includes an adhesive sheet 1 and an optical substrate 2. The adhesive sheet 1 and the optical substrate 2 are laminated together. The optical laminate 20A can be used as an optical substrate with an adhesive sheet. The optical substrate is typically in the form of a film.

[0113] Examples of the optical substrate 2 include a polarizing film, a retardation film, and a laminate film including a polarizing film and / or a retardation film. However, the optical substrate 2 is not limited to the above examples. The optical substrate 2 may also include a glass film.

[0114] The optical substrate 2 may include a polarizing film. In this case, the pressure-sensitive adhesive sheet 1 and the polarizing film may be in contact with each other.

[0115] The polarizing film includes a polarizer. The polarizing film typically includes a polarizer and a protective film (transparent protective film). The protective film is disposed, for example, in contact with the main surface (the surface having the largest area) of the polarizer. The polarizer may be disposed between two protective films. The protective film may be disposed on at least one surface of the polarizer.

[0116] The polarizer is not particularly limited, and examples include hydrophilic polymer films such as polyvinyl alcohol films, partially formalized polyvinyl alcohol films, and partially saponified ethylene-vinyl acetate copolymer films, which are uniaxially stretched after adsorbing a dichroic substance such as iodine or a dichroic dye; and oriented polyene films such as dehydrated polyvinyl alcohol and dehydrochlorinated polyvinyl chloride. Polarizers typically consist of a polyvinyl alcohol film (including partially saponified ethylene-vinyl acetate copolymer films) and a dichroic substance such as iodine.

[0117] The thickness of the polarizer is not particularly limited and may be, for example, 80 μm or less, 50 μm or less, 30 μm or less, 25 μm or less, or even 20 μm or less. The lower limit of the polarizer thickness is not particularly limited and may be, for example, 1 μm or more, 5 μm or more, 10 μm or more, or even 15 μm or more. A thin polarizer (for example, a thickness of 20 μm or less) has reduced dimensional change and can contribute to improving the durability of the optical laminate, particularly its durability at high temperatures.

[0118] The material for the protective film may be, for example, a thermoplastic resin that is excellent in transparency, mechanical strength, thermal stability, moisture barrier properties, isotropy, etc. Specific examples of such thermoplastic resins include cellulose resins such as triacetyl cellulose, polyester resins, polyethersulfone resins, polysulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, (meth)acrylic resins, cyclic polyolefin resins (norbornene-based resins), polyarylate resins, polystyrene resins, polyvinyl alcohol resins, and mixtures thereof. The material for the protective film may be a thermosetting resin or an ultraviolet-curable resin such as a (meth)acrylic, urethane, acrylic urethane, epoxy, or silicone-based resin. When the polarizing film has two protective films, the materials of the two protective films may be the same or different. For example, a protective film made of a thermoplastic resin may be bonded to one main surface of a polarizer via an adhesive, and a protective film made of a thermosetting resin or an ultraviolet-curable resin may be bonded to the other main surface of the polarizer. The protective film may contain one or more optional additives, such as ultraviolet absorbers, antioxidants, lubricants, plasticizers, release agents, color inhibitors, flame retardants, nucleating agents, antistatic agents, pigments, and colorants.

[0119] The thickness of the protective film can be determined as appropriate, but is generally about 10 to 200 μm in terms of strength, workability such as handling, thinness, and the like.

[0120] The polarizer and the protective film are usually adhered to each other via an aqueous adhesive or the like. Examples of aqueous adhesives include isocyanate-based adhesives, polyvinyl alcohol-based adhesives, gelatin-based adhesives, vinyl latex, aqueous polyurethane, and aqueous polyester. Examples of adhesives other than the above-mentioned adhesives include ultraviolet-curable adhesives and electron beam-curable adhesives. Electron beam-curable polarizing film adhesives exhibit suitable adhesiveness to various protective films. The adhesive may contain a metal compound filler.

[0121] In the polarizing film, a retardation film or the like can be formed on the polarizer instead of the protective film. Another protective film or a retardation film or the like can be further provided on the protective film.

[0122] The protective film may have a hard coat layer on the surface opposite to the surface bonded to the polarizer, and may also be subjected to treatments for purposes such as anti-reflection, anti-sticking, diffusion, and anti-glare.

[0123] The polarizing film may be a circular polarizing film.

[0124] The thickness of the polarizing film is, for example, 500 μm or less, and may be 300 μm or less, 200 μm or less, 100 μm or less, or even 60 μm or less. The lower limit of the thickness may be, for example, 10 μm or more, 25 μm or more, or even 40 μm or more.

[0125] A retardation film is a film having birefringence in the in-plane direction and / or the thickness direction, and is, for example, a stretched resin film or a film in which a liquid crystal material is oriented and fixed.

[0126] The retardation film may be a λ / 4 plate, a λ / 2 plate, an anti-reflection retardation film (see, for example, paragraphs 0221, 0222, and 0228 of JP 2012-133303 A), a viewing angle compensation retardation film (see, for example, paragraphs 0225 and 0226 of JP 2012-133303 A), or an obliquely oriented viewing angle compensation retardation film (see, for example, paragraph 0227 of JP 2012-133303 A). The retardation film is not limited to the above examples, as long as it has birefringence in the in-plane direction and / or the thickness direction. The retardation value, arrangement angle, three-dimensional birefringence, whether the retardation film is single-layer or multi-layer, and the like are also not limited. Known films can be used as the retardation film.

[0127] The optical substrate 2 has a thickness of, for example, 1 to 200 μm.

[0128] The optical substrate 2 may be a single layer or a laminated film composed of two or more layers. When the optical substrate 2 is a laminated film, the pressure-sensitive adhesive sheet 1 may be used to bond the layers together.

[0129] Another example of an optical laminate according to an embodiment of the present invention is shown in Figure 4. Optical laminate 20B in Figure 4 has a layered structure in which a release liner 3, a pressure-sensitive adhesive sheet 1, and an optical substrate 2 are layered in this order. By peeling off release liner 3, optical laminate 20B can be used as an optical substrate with a pressure-sensitive adhesive sheet.

[0130] The release liner 3 is typically a resin film. Examples of resins that can be used to form the release liner 3 include polyesters such as polyethylene terephthalate (PET), polyolefins such as polyethylene and polypropylene, polycarbonate, acrylic, polystyrene, polyamide, and polyimide. The surface of the release liner 3 that comes into contact with the pressure-sensitive adhesive sheet 1 may be subjected to a release treatment. The release treatment may be, for example, a treatment using a silicone compound. However, the release liner 3 is not limited to the above examples. The release liner 3 is peeled off when the optical laminate 20B is used, for example, when it is attached to the image-forming layer.

[0131] Another example of an optical laminate according to an embodiment of the present invention is shown in Fig. 5. Optical laminate 20C in Fig. 5 has a layered structure in which a release liner 3, a pressure-sensitive adhesive sheet 4, a retardation film 2B, a pressure-sensitive adhesive sheet 1, and a polarizing film 2A are layered in this order. After peeling off release liner 3, optical laminate 20C can be used by being attached to, for example, an image-forming layer.

[0132] A known adhesive sheet can be used for the adhesive sheet 4. The adhesive sheet 1 may also be used for the adhesive sheet 4.

[0133] Another example of an optical laminate according to an embodiment of the present invention is shown in Fig. 6. Optical laminate 20D in Fig. 6 has a layered structure in which a release liner 3, a pressure-sensitive adhesive sheet 4, a retardation film 2B, a pressure-sensitive adhesive sheet 1, a polarizing film 2A, and a protective film 5 are layered in this order. After peeling off release liner 3, optical laminate 20D can be used by being attached to, for example, an image-forming layer.

[0134] The protective film 5 has the function of protecting the polarizing film 2A, which is the outermost layer, during distribution and storage of the optical laminate 20D and when the optical laminate 20D is incorporated into an image display device. The protective film 5 may also function as a window to the external space when incorporated into an image display device. The protective film 5 is typically a resin film. Examples of resins constituting the protective film 5 include polyesters such as PET, polyolefins such as polyethylene and polypropylene, acrylics, cycloolefins, polyimides, and polyamides, with polyesters being preferred. However, the protective film 5 is not limited to the above examples. The protective film 5 may also be a glass film or a laminate film including a glass film. The protective film 5 may be subjected to surface treatments such as anti-glare, anti-reflection, and anti-static.

[0135] The protective film 5 may be bonded to the optical substrate 2 by any adhesive. Bonding by an adhesive sheet 1 is also possible.

[0136] The optical laminate may have any configuration as long as it includes the pressure-sensitive adhesive sheet 1 and the optical substrate 2.

[0137] The pressure-sensitive adhesive sheet 1 can be disposed between any layers included in the optical laminate.

[0138] The optical laminate according to the embodiment of the present invention can be distributed and stored, for example, as a rolled body obtained by rolling up a strip-shaped optical laminate, or as a sheet-shaped optical laminate.

[0139] The optical laminate according to the embodiment of the present invention is typically used in an image display device, such as a liquid crystal display, an EL display such as an organic EL display, or an inorganic EL display.

[0140] ≪≪3. Image display device≫≫ An example of an image display device according to an embodiment of the present invention is shown in Fig. 7. The image display device 21 in Fig. 7 has a layered structure in which a substrate 7, an image-forming layer (e.g., an organic EL layer or a liquid crystal layer) 6, an adhesive sheet 4, a retardation film 2B, an adhesive sheet 1, a polarizing film 2A, and a protective film 5 are layered in this order. The image display device 21 has the optical laminate 20D of Fig. 6 (excluding the release liner 3). The image display device 21 may have the optical laminates 20A, 20B, and 20C of Figs. 3 to 5 instead of the optical laminate 20D (excluding the release liner 3). The substrate 7 and the image-forming layer 6 may have the same configurations as the substrate and the image-forming layer, respectively, of known image display devices.

[0141] The image display device 21 in FIG. 7 may be an organic EL display or a liquid crystal display. However, the image display device 21 is not limited to this example. The image display device 21 may also be an electroluminescence (EL) display, a plasma display (PD), a field emission display (FED), or the like. The image display device 21 may be used for home appliances, in-vehicle applications, public information displays (PID), and the like. Among the above examples, the image display device 21 for in-vehicle applications is particularly likely to be exposed to high-temperature environments.

[0142] The image display device 21 may have any configuration as long as it includes the pressure-sensitive adhesive sheet 1 and / or the optical laminate 20. [Example]

[0143] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited thereto.

[0144] [Preparation of Pressure-Sensitive Adhesive Composition] (Prepolymer P1) 99 parts by weight of n-butyl acrylate (BA), 1 part by weight of 4-hydroxybutyl acrylate (4-HBA), and 0.2 parts by weight of Omnirad 127D (IGM Resin) as a photopolymerization initiator were placed in a four-neck flask. The liquid in the flask was then irradiated with ultraviolet light under a nitrogen atmosphere to partially photopolymerize the monomers, yielding prepolymer P1. UV irradiation was continued until the viscosity of the liquid in the flask reached 10 Pa·s (measurement conditions: BH viscometer No. 5 rotor, 10 rpm, measurement temperature 30°C).

[0145] (Adhesive compositions A1 to A10) Next, prepolymer P1, additional monomers, and a crosslinker (NDDA: 1,9-nonanediol diacrylate) were mixed to obtain the compositions shown in Table 1 below, thereby obtaining photocurable pressure-sensitive adhesive compositions A1 to A10. For the additional monomers, the values ​​of the regression equation shown in formula (Y) were calculated from the quantum chemical calculations using the DFT method described above and calculations using RDkit software and HSPiP software. The values ​​of a to g in the regression equation for each additional monomer are shown in Table 2. The quantum chemical calculations were performed using the general-purpose quantum chemical calculation program Gaussian 16 (version AM64L-G16RevC.01). The version of the RDkit software used was 2022.09.1. The version of the HSPiP software used was 5.3.03.1.

[0146] [Table 1]

[0147] [Table 2]

[0148] The final composition of the monomers contained in each adhesive composition is shown in Table 3 below.

[0149] [Table 3]

[0150] [Preparation of adhesive sheet] Example 1 (Preparation of release liner) A silicone-based release agent composition was prepared by mixing 30 parts by weight of an addition reaction curable silicone (LTC761, a 30 wt% toluene solution containing a hexenyl group-containing polyorganosiloxane, manufactured by Dow Corning Toray Co., Ltd.), 0.9 parts by weight of a release control agent (BY24-850, containing an unreactive silicone resin, manufactured by Dow Corning Toray Co., Ltd.), 2 parts by weight of a curing catalyst (SRX212, containing a platinum catalyst, manufactured by Dow Corning Toray Co., Ltd.), and a toluene / hexane mixed solvent (volume ratio 1:1) as a diluent. The silicone solids concentration in the release agent composition was 1.0 wt%. Next, the release agent composition was applied to one side of a liner substrate (Lumirror XD500P polyester film, 75 μm thick) using a wire bar and heated at 130°C for 1 minute to prepare a release liner with a release layer (60 nm thick) on one side.

[0151] (Preparation of adhesive sheet) The PSA composition A1 was applied to one side of a substrate sheet (PET separator, manufactured by Mitsubishi Plastics, MRF38) using an applicator to form a coating layer (thickness: 20 μm). Next, a release liner was placed on the formed coating layer to obtain a first laminate. The release liner was placed so that the release layer was in contact with the coating layer. Next, an illuminance of 9 mW / cm was applied from the substrate sheet side of the first laminate. 2 and irradiation time was 56 seconds (integrated light dose 500 mJ / cm 2 An LED was used as the light source, and the peak wavelength of the irradiated light was 340 nm. Furthermore, an illuminance of 9 mW / cm was applied from the side of the base sheet of the first laminate. 2 and irradiation time was 22 seconds (integrated light dose 200 mJ / cm 2 ). A metal halide lamp was used as the light source. This photocured the coating layer, yielding the PSA sheet of Example 1 (thickness 20 μm) sandwiched between the base sheet and release liner. The illuminance of the light was measured using an illuminance meter (UD-T3040T2, manufactured by Topcon Technohouse Co., Ltd.) at a position on the base sheet near the surface where ultraviolet light enters.

[0152] <Examples 2 to 7 and Comparative Examples 1 to 3> Pressure-sensitive adhesive sheets of Examples 2 to 7 and Comparative Examples 1 to 3 were obtained in the same manner as in Example 1, except that the pressure-sensitive adhesive composition used was changed.

[0153] [Adhesive sheet evaluation method] The following evaluations were carried out for each of the produced pressure-sensitive adhesive sheets.

[0154] <Mw of polymer> Compositions were prepared that had the same formulations as the pressure-sensitive adhesive compositions used in Examples 1 to 7 and Comparative Examples 1 to 3, except that they did not contain a crosslinking agent. For each of the prepared compositions, a coating film was formed in the same manner as in Example 1, and the formed coating film was irradiated with light. This caused the monomer components contained in the composition to polymerize, forming a polymer. The Mw of this polymer was measured. The Mw was measured by GPC. The measurement equipment and measurement conditions were as follows:

[0155] Analytical equipment: Agilent Technologies, Agilent 1200 Column: Tosoh Corporation, TSKgel SuperAWM-H + superAW4000 + superAW2500 Column size: 6.0mmφ x 15cm each, total 45cm Column temperature: 40℃ ·Flow rate: 0.4mL / min ·Injection volume: 40μL Eluent: N,N-dimethylformamide (DMF) Detector: Differential refractometer (RI) Standard sample: Polystyrene

[0156] <Polymerization rate> The polymerization rate of the pressure-sensitive adhesive sheet was calculated from the change in weight of the pressure-sensitive adhesive sheet before and after 2 hours of heat drying at 130° C. Specifically, the weight of the pressure-sensitive adhesive sheet immediately after peeling the base sheet and release liner from the second laminate was defined as W0 (weight before drying), and the weight of the pressure-sensitive adhesive sheet after cooling at room temperature (23° C.) for about 20 minutes after the heating was defined as W1 (weight after drying), and the polymerization rate was calculated using the formula: polymerization rate (%) = W1 / W0 × 100.

[0157] <Reliability test> (Preparation of polarizing film) A 45 μm-thick polyvinyl alcohol film was stretched 3 times between rolls with different speed ratios while dyeing in a 0.3% iodine solution at 30°C for 1 minute. Next, the film was stretched to a total stretch ratio of 6 times while immersed in an aqueous solution containing 4% boric acid and 10% potassium iodide at 60°C for 0.5 minutes. The film was then immersed in an aqueous solution containing 1.5% potassium iodide at 30°C for 10 seconds, washed, and then dried at 50°C for 4 minutes to obtain an 18 μm-thick polarizer. A hard-coated triacetyl cellulose (TAC) film (saponified, 40 μm thick) was bonded to one side of the polarizer as a protective film, with the triacetyl cellulose film side bonded using a polyvinyl alcohol-based adhesive. A 30 μm-thick acrylic film was then bonded to the other side of the polarizer as a protective film using a polyvinyl alcohol-based adhesive, thereby producing a polarized film. Furthermore, the discharge amount to the surface of the polarizing film on the acrylic film side is 63 W / m 2 Corona treatment was carried out in minutes.

[0158] (Preparation of polarizing film with adhesive sheet) A polarizing film with a pressure-sensitive adhesive sheet was prepared by placing the polarizing film on the exposed surface of the pressure-sensitive adhesive sheet to be evaluated. The polarizing film was placed so that the surface of the acrylic film was in contact with the pressure-sensitive adhesive sheet.

[0159] <Reliability test (95℃)> The reliability (95°C reliability) of the prepared polarizing film with adhesive sheet was evaluated using the following method. First, the polarizing film with adhesive sheet was cut into a strip measuring 228 mm long x 128 mm wide to prepare a test specimen. Next, the test specimen was attached to the surface of 0.7 mm thick alkali-free glass (manufactured by Corning Incorporated, product name "EG-XG") using the adhesive sheet. The test specimen was attached to the alkali-free glass using a laminator. After attaching the test specimen, it was placed in an autoclave at 50°C and 0.5 MPa for 15 minutes to homogenize the bond between the alkali-free glass and the adhesive sheet, and the adhesive sheet was adhered to the alkali-free glass. Next, the test specimen was heat-treated at 95°C under atmospheric pressure for 500 hours. The vicinity of the edge of the test specimen was observed using an optical microscope to check for peeling from the edge of the test specimen and the presence or absence of bubbles near the edge. A: No peeling or bubbling that affects image display was observed. B: There is a slight amount of foaming at the edge, but it is not enough to affect the image display. C: There are several bubbles at the edge, but they do not affect the image display. D: Peeling and / or bubbling that affects image display

[0160] <Reliability test (105℃)> The 105°C reliability was evaluated using the same method as for the 95°C reliability, except that the heat treatment temperature was changed from 95°C to 105°C. The evaluation items in categories A to D were the same as those for the 95°C reliability.

[0161] The evaluation results are shown in Table 4 below.

[0162] [Table 4]

[0163] As shown in Table 4, the pressure-sensitive adhesive sheets of the examples had improved reliability in high-temperature environments compared to the pressure-sensitive adhesive sheets of the comparative examples. [Industrial Applicability]

[0164] The pressure-sensitive adhesive sheet of the present invention is suitable for use in image display devices, particularly image display devices that may be exposed to high-temperature environments.

Claims

1. A pressure-sensitive adhesive sheet formed from a photocurable pressure-sensitive adhesive composition containing a monomer component M, The monomer component M includes a monomer m represented by the following formula (1): 【Chemistry 1】 For the monomer m, the value of the regression equation shown in the following formula (Y) is 8.00 or more: Adhesive sheet. Formula (Y): 20.63a-0.6602b+0.2859c+0.2797d+0.2050e+0.1180f+0.000865g-0.8069 however, X in the formula (1) 1 The number of atoms that make up X 2 is smaller than the number of atoms constituting the X 3 is a hydrogen atom, or X 2 It bonds to form a ring structure, a in the formula (Y) is X in a state of being contained in the monomer m, which is obtained by standard structural optimization that can be performed by quantum chemical calculations using the density functional method with B3LYP / 6-31G(d,p) as a basis function. 1 is the charge by Mulliken's method, b and c are the descriptors VSA_EState5 and VSA_EState7, respectively, included in the RDkit software; d is the descriptor Num Aliphatic Heterocycles included in the RDkit software; e is the descriptor δD included in the HSPiP software, f is the descriptor PEOE_VSA1 included in the RDkit software, g is the descriptor AntB included in the HSPiP software.

2. The pressure-sensitive adhesive sheet according to claim 1 , wherein the value of c is 1.15 or more.

3. The pressure-sensitive adhesive sheet according to claim 1 , wherein the value of g is 1680 or more.

4. The pressure-sensitive adhesive sheet according to claim 1 , wherein the value of a is 0.1 or more and the value of e is 16 or more.

5. X in the formula (1) 1 The pressure-sensitive adhesive sheet according to claim 1 , wherein is a hydrogen atom or a methyl group.

6. X in the formula (1) 2 The pressure-sensitive adhesive sheet according to claim 1 , wherein

7. The pressure-sensitive adhesive sheet according to claim 6 , wherein the aliphatic heterocycle does not contain a nitrogen atom.

8. The pressure-sensitive adhesive sheet according to claim 6 , wherein the aliphatic heterocycle is a five- or more-membered ring.

9. The pressure-sensitive adhesive sheet according to claim 6 , wherein the aliphatic heterocycle is a cyclic ether.

10. X in the formula (1) 3 The pressure-sensitive adhesive sheet according to claim 1 , wherein is a hydrogen atom.

11. The pressure-sensitive adhesive sheet according to claim 1 , wherein the monomer m is a (meth)acrylate monomer.

12. The pressure-sensitive adhesive sheet according to claim 1 , wherein the monomer m is a monomer represented by the following formula (2): 【Chemistry 2】 X in the formula (2) 4 is a cyclic ether group, L is a single bond, an alkylene group, a carboxylic acid ester group, or a group in which an alkylene group and a carboxylic acid ester group are combined.

13. 2. The pressure-sensitive adhesive sheet according to claim 1, wherein the content of said monomer m in said monomer component M is 4 to 20% by weight.

14. The pressure-sensitive adhesive sheet according to claim 1 , wherein the polymerization rate of the monomer component M in the pressure-sensitive adhesive sheet is 95% or more.

15. The pressure-sensitive adhesive sheet according to claim 1 , wherein the monomer component M is substantially free of a carboxyl group-containing monomer.

16. The pressure-sensitive adhesive sheet according to claim 1, wherein the pressure-sensitive adhesive sheet has a thickness of 5 to 30 μm.

17. The pressure-sensitive adhesive sheet according to claim 1 , wherein the content of the solvent in the pressure-sensitive adhesive sheet is 5% by weight or less.

18. The pressure-sensitive adhesive sheet according to claim 1 , which is used to attach an optical substrate containing a polarizing film.

19. An optical laminate comprising the pressure-sensitive adhesive sheet according to any one of claims 1 to 18 and an optical substrate.

20. The optical laminate according to claim 19 , wherein the optical substrate comprises a polarizing film.

21. The optical laminate according to claim 20 , wherein the pressure-sensitive adhesive sheet and the polarizing film are in contact with each other.

22. An image display device comprising the optical laminate according to claim 19.

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