JP6200838B2 - Adhesive, adhesive sheet, and image display device - Google Patents

Description

  The present invention relates to an adhesive, an adhesive sheet, and an image display device.

  Adhesives and adhesive sheets (adhesive tapes) using the same are widely used in various industrial fields. As a specific use, for example, there is a protective film used by being attached to the surface of glass or the like. As said glass, window glass, such as a mobile telephone, a smart phone, a motor vehicle, a building, is mentioned, for example.

  Examples of the adhesive include an acrylic resin adhesive, a rubber adhesive, and a urethane adhesive. Among these, urethane pressure-sensitive adhesives are widely used because they are excellent in properties such as re-peelability (property that can be easily peeled off after being attached to an adherend) (Patent Documents 1 and 2, etc.).

JP 2001-192636 A JP 2011-190420 A

  However, when the pressure-sensitive adhesive sheet is peeled off (re-peeled) from the adherend, the surface of the adherend is caused by the adhesive remaining on the surface of the adherend or the adhesion of dirt to the remaining pressure-sensitive adhesive. There is a risk of contamination. For this reason, in the pressure-sensitive adhesive and the pressure-sensitive adhesive sheet using the same, when the pressure-sensitive adhesive sheet is peeled off (re-peeled) from the adherend, the property that the surface of the adherend is hardly contaminated (contamination resistance) is important. It is.

  Then, an object of this invention is to provide the adhesive, the adhesive sheet, and the image display apparatus which were excellent in the stain resistance with respect to the to-be-adhered body surface.

In order to achieve the above object, the pressure-sensitive adhesive of the present invention comprises:
A pressure-sensitive adhesive containing the following components (A) and (B),

(A) Prepolymer of polyurethane (B) Crosslinking agent

The prepolymer (A) has a hydroxyl group,
The crosslinking agent (B) has an isocyanate group, and
The pressure-sensitive adhesive satisfies at least one of the following conditions [I] and [II].

[I] The prepolymer (A) is a polyurethane polyol obtained by reacting a polyol and a polyisocyanate, and the polyol does not contain a nitrogen atom,
And,
The crosslinking agent (B) includes the following (B1).

(B1) Biuret having three isocyanate groups in one molecule

[II] The crosslinking agent (B) contains at least one selected from the group consisting of the following (B2) to (B5).

(B2) allophanate having two isocyanate groups in one molecule (B3) uretdione having two isocyanate groups in one molecule (B4) urethane prepolymer having two isocyanate groups in one molecule (B5) in one molecule Biuret with two isocyanate groups

  The pressure-sensitive adhesive sheet of the present invention is a pressure-sensitive adhesive sheet in which a pressure-sensitive adhesive layer is formed on at least one surface of a substrate, and the pressure-sensitive adhesive layer is a pressure-sensitive adhesive layer formed using the pressure-sensitive adhesive of the present invention. To do.

  The image display device of the present invention is an image display device in which a protective sheet of the image display device is attached to an image display surface, and the protective sheet is the pressure-sensitive adhesive sheet of the present invention.

  ADVANTAGE OF THE INVENTION According to this invention, it is possible to provide the adhesive, the adhesive sheet, and image display apparatus which were excellent in the stain resistance with respect to the to-be-adhered body surface.

  Hereinafter, the present invention will be described with examples. However, the present invention is not limited by the following description.

  In the present invention, the “prepolymer” refers to a polymer in a state where polymerization or crosslinking has progressed partway, and further allows polymerization or crosslinking to proceed. In the present invention, the “polyurethane prepolymer” or “urethane prepolymer” refers to a polyurethane in a state where polymerization or crosslinking has progressed partway and which can be converted into a polyurethane having undergone polymerization or crosslinking. The “polyurethane prepolymer” can be converted into a polyurethane having further polymerized or crosslinked by having a plurality of hydroxyl groups or isocyanate groups.

  In the present invention, “polyurethane polyol” refers to a prepolymer of polyurethane having a plurality of hydroxyl groups. Further, in the present invention, unless otherwise specified, the “urethane prepolymer” is a polyurethane that can be converted into a polyurethane further polymerized or crosslinked by having a plurality of isocyanate groups (for example, at both ends of the molecule). A prepolymer.

  In the present invention, “polyol” refers to an organic compound having a plurality (two or three or more) of hydroxyl groups (preferably at least one of alcoholic hydroxyl groups and phenolic hydroxyl groups) in one molecule. “Polyisocyanate” refers to an organic compound (polyfunctional isocyanate) having a plurality (2 or 3 or more) of isocyanate groups (also referred to as isocyanato groups), that is, (—N═C═O), in one molecule.

In the present invention, “biuret” is not particularly limited, but refers to, for example, a compound represented by the following chemical formula (Biu).

  In the chemical formula (Biu), each R is a hydrogen atom or an arbitrary substituent, and may be the same or different.

In the present invention, “allophanate” is not particularly limited, but refers to, for example, a compound represented by the following chemical formula (Allo).

  In the chemical formula (Allo), each R is a hydrogen atom or an arbitrary substituent, and may be the same or different.

In the present invention, the aforementioned (B1), that is, “biuret having three isocyanate groups in one molecule” is not particularly limited, but refers to, for example, a compound represented by the following chemical formula (B1).

In the chemical formula (B1), R ¹⁰¹ , R ¹⁰² and R ¹⁰³ are each an arbitrary atomic group and may be the same or different.

In the chemical formula (B1), R ¹⁰¹ , R ¹⁰² and R ¹⁰³ may be, for example, a hydrocarbon group. The hydrocarbon group may be saturated or unsaturated, may be linear or branched, may or may not contain a cyclic structure, and may or may not contain an aromatic ring. It may be substituted with a further substituent or may not be substituted.

In the chemical formula (B1), R ¹⁰¹ , R ^102, and R ¹⁰³ are each a linear or branched alkylene group, a linear or branched unsaturated hydrocarbon group, or an alicyclic hydrocarbon group. preferable. In the chemical formula (B1), R ¹⁰¹ , R ¹⁰² and R ¹⁰³ are each a linear or branched alkylene group having 1 to 6 carbon atoms or a linear or branched unsaturated group having 2 to 6 carbon atoms. More preferably, it is a hydrocarbon group or an alicyclic hydrocarbon group having 5 to 24 carbon atoms. The “linear or branched unsaturated hydrocarbon group” is not particularly limited, and examples thereof include a linear or branched alkenylene group and a linear or branched alkynylene group.

In R ¹⁰¹ , R ¹⁰² and R ¹⁰³ , the “linear or branched alkylene group” is, for example, a methylene group, a dimethylene group (ethylene group), a trimethylene group, a tetramethylene group, a pentamethylene group, and a hexamethylene group, Etc. The “straight chain or branched unsaturated hydrocarbon group” is, for example, a group in which one or more single bonds in the “straight chain or branched alkylene group” are unsaturated bonds, specifically, A vinylene group etc. are mentioned. Examples of the “alicyclic hydrocarbon group” include 1,2-cyclopentylene group, 1,3-cyclopentylene group, 1,2-cyclohexylene group, 1,3-cyclohexylene. Group, 1,4-cyclohexylene group and the like.

In the present invention, the (B2), that is, “allophanate having two isocyanate groups” is not particularly limited, but for example, refers to a compound represented by the following chemical formula (B2).

In Chemical Formula ^{(B2), R 101} and ^{R 103} are the same as ^{R 101} and ^{R 103} in the formula (B1). In the present invention, when using both the chemical equation (B1) a compound of formula (B2), ^{R 101} in ^{R 101} and Formula in Formula (B1) (B5) may be the same or different, Formula (B1) ^{R 103} in the ^{R 103} and the formula (B2) in may be the same or different. R ¹⁰⁴ is an arbitrary atomic group. R ¹⁰⁴ may be, for example, a hydrogen atom or a hydrocarbon group, and may or may not be substituted with a further substituent. In R ¹⁰⁴ , the hydrocarbon group may be saturated or unsaturated, linear or branched, may or may not contain a cyclic structure, and may contain an aromatic ring. You don't have to leave. The hydrocarbon group is more preferably a straight chain or branched alkyl group, a straight chain or branched unsaturated hydrocarbon group, or an alicyclic hydrocarbon group, and is a straight chain or branched chain having 1 to 12 carbon atoms. It is more preferably a branched alkyl group, a straight chain or branched unsaturated hydrocarbon group having 2 to 10 carbon atoms, or an alicyclic hydrocarbon group having 5 to 24 carbon atoms, and a straight chain having 4 to 12 carbon atoms. Or it is more preferable that it is a branched alkyl group. The “linear or branched unsaturated hydrocarbon group” is not particularly limited, and examples thereof include a linear or branched alkenyl group and a linear or branched alkynyl group.

In the present invention, the above (B3), that is, “uretdione having two isocyanate groups” is not particularly limited, but for example, refers to a compound represented by the following chemical formula (B3).

In the chemical formula (B3), R ²⁰¹ and R ²⁰² each represent an arbitrary atomic group, and may be the same or different.

In the chemical formula (B3), R ²⁰¹ and R ²⁰² are each preferably a linear or branched alkylene group, a linear or branched unsaturated hydrocarbon group, or an alicyclic hydrocarbon group. In the chemical formula (B1), R ²⁰¹ and R ²⁰² are each a linear or branched alkylene group having 1 to 6 carbon atoms or a linear or branched unsaturated hydrocarbon group having 2 to 6 carbon atoms. Or an alicyclic hydrocarbon group having 5 to 24 carbon atoms. The “linear or branched unsaturated hydrocarbon group” is not particularly limited, and examples thereof include a linear or branched alkenylene group and a linear or branched alkynylene group.

In R ²⁰¹ and R ²⁰² , examples of the “linear or branched alkylene group” include a methylene group, a dimethylene group (ethylene group), a trimethylene group, a tetramethylene group, a pentamethylene group, and a hexamethylene group. . The “straight chain or branched unsaturated hydrocarbon group” is, for example, a group in which one or more single bonds in the “straight chain or branched alkylene group” are unsaturated bonds, specifically, A vinylene group etc. are mentioned. Examples of the “alicyclic hydrocarbon group” include 1,2-cyclopentylene group, 1,3-cyclopentylene group, 1,2-cyclohexylene group, 1,3-cyclohexylene. Group, 1,4-cyclohexylene group and the like.

In the present invention, the above (B4), that is, “urethane prepolymer having two isocyanate groups” is not particularly limited, but for example, refers to a compound represented by the following chemical formula (B4).

In the chemical formula (B4), R ³⁰¹ and R ³⁰² are arbitrary atomic groups, and may be the same or different.

R ³⁰¹ and R ³⁰² may be, for example, a hydrocarbon group. The hydrocarbon group may be saturated or unsaturated, may be linear or branched, may or may not contain a cyclic structure, and may or may not contain an aromatic ring. It may be substituted with a further substituent or may not be substituted.

In the chemical formula (B4), R ³⁰¹ and R ³⁰² are each preferably a linear or branched alkylene group, or a linear or branched unsaturated hydrocarbon group or alicyclic hydrocarbon group. In the chemical formula (B4), R ³⁰¹ and R ³⁰² are each a linear or branched alkylene group having 1 to 6 carbon atoms or a linear or branched unsaturated hydrocarbon group having 2 to 6 carbon atoms. Or an alicyclic hydrocarbon group having 5 to 24 carbon atoms. The “linear or branched unsaturated hydrocarbon group” is not particularly limited, and examples thereof include a linear or branched alkenylene group and a linear or branched alkynylene group.

In R ³⁰¹ and R ³⁰² , examples of the “linear or branched alkylene group” include a methylene group, a dimethylene group (ethylene group), a trimethylene group, a tetramethylene group, a pentamethylene group, and a hexamethylene group. . The “straight chain or branched unsaturated hydrocarbon group” is, for example, a group in which one or more single bonds in the “straight chain or branched alkylene group” are unsaturated bonds, specifically, A vinylene group etc. are mentioned. Examples of the “alicyclic hydrocarbon group” include 1,2-cyclopentylene group, 1,3-cyclopentylene group, 1,2-cyclohexylene group, 1,3-cyclohexylene. Group, 1,4-cyclohexylene group and the like.

Alternatively, in R ³⁰³ in the chemical formula (B4), HOR ³⁰³ OH may be, for example, polyether polyol (bifunctional diol), polymer polyol, acrylic polyol, polyolefin polyol, or the like. HOR ³⁰³ OH may be a diol or a trivalent (trifunctional) or higher polyol. Examples of the polyether polyol (bifunctional diol) include PEG (polyethylene glycol), PPG (polypropylene glycol), PTMG (polytetramethylene glycol), poly (2-methyltetramethylene) glycol, and the like. Examples of the polymer polyol include polyester polyol. Examples of the polyester polyol include one or more of carboxylic acids (dibasic acids) such as succinic acid, adipic acid, sebacic acid, dimer acid, maleic anhydride, phthalic anhydride, isophthalic acid, and terephthalic acid. And polyester polyols obtained by a condensation reaction with one or more of polyhydric alcohols such as ethylene glycol, propylene glycol, diethylene glycol, neopentyl glycol, trimethylolpropane, and glycerin. Examples of the polyester polyol include polycaprolactones obtained by ring-opening polymerization of ε-caprolactone to a polyhydric alcohol. Examples of the polycaprolactones include polycaprolactone polyols obtained by ring-opening polymerization of one or more types such as tetramethylene carbonate and hexamethylene carbonate to polyhydric alcohols. Examples of the polyolefin polyol include polybutene having two or more hydroxyl groups, hydrogenated polybutadiene, polyisoprene, hydrogenated polyisoprene, terminal hydroxyl group polybutadiene, and isoprene. Preferred examples of the polyol represented by HOR ³⁰³ OH are the low molecular weight polyols and polyester polyols described above, more preferably polyester polyols, and most preferably, ε-caprolactone is ring-opened to the low molecular weight polyols. It is a polycaprolactone polyol obtained by polymerization. Further, the molecular weight of HOR ³⁰³ OH is not particularly limited, but is preferably 300 or more, and the upper limit is not particularly limited, but is, for example, 1800 or less.

In the present invention, the (B5), that is, “biuret having two isocyanate groups” is not particularly limited, but refers to, for example, a compound represented by the following chemical formula (B5).

In the chemical formula (B5), R ¹⁰¹ is the same as R ¹⁰¹ and R ^{102 in the} chemical formulas (B1) and (B2). R ¹⁰² is the same as ^{R 102} in the formula (B1). In addition, in this invention, when using 2 or more types among 3 types of compounds of chemical formula (B1), (B2), and (B5), each ^R101 may be same or different. In the present invention, when using both the compound of formula (B1) and (B5), ^{R 102} in ^{R 102} and Formula (B5) in the chemical formula (B1) may be the same or different. In the chemical formula (B5), R ¹⁰⁵ is an arbitrary atomic group. R ¹⁰⁵ is, for example, a hydrogen atom, a hydrocarbon group, an acyl group (—CO—R, R is a hydrogen atom or a hydrocarbon group), a carboxy group, or an alkoxycarbonyl group (—CO—O—R, R is a hydrocarbon. Group), it may be substituted with a further substituent or may be unsubstituted. In R ¹⁰⁵ , the hydrocarbon group, the hydrocarbon group in the acyl group, and the hydrocarbon group in the alkoxycarbonyl group may be saturated or unsaturated, may be linear or branched, and have a cyclic structure. It may or may not be included, and may or may not include an aromatic ring. The hydrocarbon group is more preferably a straight chain or branched alkyl group, a straight chain or branched unsaturated hydrocarbon group, or an alicyclic hydrocarbon group, and is a straight chain having 1 to 6 carbon atoms or More preferably, it is a branched alkyl group, a linear or branched unsaturated hydrocarbon group having 2 to 6 carbon atoms, or an alicyclic hydrocarbon group having 5 to 24 carbon atoms. The “linear or branched unsaturated hydrocarbon group” is not particularly limited, and examples thereof include a linear or branched alkenyl group and a linear or branched alkynyl group.

  In the pressure-sensitive adhesive of the present invention, the crosslinking agent (B) preferably contains at least one selected from the group consisting of (B2) to (B4).

  In the pressure-sensitive adhesive of the present invention, the prepolymer (A) is a polyurethane polyol obtained by reacting a polyol and a polyisocyanate, and the polyol preferably does not contain a nitrogen atom. The prepolymer (A) is preferably a polyurethane polyol obtained by reacting a polyol having three or more hydroxyl groups in one molecule with a polyisocyanate having two isocyanate groups in one molecule.

In the pressure-sensitive adhesive of the present invention, the prepolymer (A) is a prepolymer obtained by reacting at least one selected from the group consisting of the following component (a1) and the following components (a2) to (a5). Preferably there is. The prepolymer (A) is preferably a prepolymer obtained by reacting the following component (a1) with at least one selected from the group consisting of the following components (a2) to (a4).

(A1) Polyol having three or more hydroxyl groups in one molecule (a2) Allophanate having two isocyanate groups in one molecule (a3) Uretodione having two isocyanate groups in one molecule (a4) Isocyanate in one molecule Urethane prepolymer having two groups (a5) Biuret having two isocyanate groups in one molecule

  Although the said component (a2) is not specifically limited, For example, the compound represented by the said Chemical formula (B2) may be sufficient. Although the said component (a3) is not specifically limited, For example, the compound represented by the said Chemical formula (B3) may be sufficient. Although the said component (a4) is not specifically limited, For example, the compound represented by the said Chemical formula (B4) may be sufficient. Although the said component (a5) is not specifically limited, For example, the compound represented by the said Chemical formula (B5) may be sufficient.

  The component (a1) is not particularly limited, but is preferably triol type polypropylene glycol (PPG).

  The component (a4) is preferably a urethane prepolymer obtained by reacting a polyol and a polyisocyanate. More preferably, the polyisocyanate in the component (a4) is hexamethylene diisocyanate. Moreover, it is preferable that the said polyol in the said component (a4) is diol. The diol is more preferably a diol having an average molecular weight of 250 to 1800, and even more preferably a diol having an average molecular weight of 250 to 1600. In the case where the polyol in the component (a4) is a diol, the component (a1) is more preferably a triol type polypropylene glycol (PPG).

  In the pressure-sensitive adhesive of the present invention, the number of isocyanate groups of the crosslinking agent (B) is preferably 1.4 to 2.0 in terms of molar ratio with respect to the number of hydroxyl groups of the prepolymer (A).

The pressure-sensitive adhesive of the present invention further contains a carboxylic acid ester, and the carboxylic acid ester preferably satisfies at least one of the following conditions [III] and [IV].

[III] The carboxylic acid ester contains an ether bond in the molecule.

[IV] The carboxylic acid ester contains 31 or more carbon atoms in one molecule.

  In the pressure-sensitive adhesive of the present invention, the carboxylic acid ester preferably contains a plurality of ether bonds in one molecule.

  In the pressure-sensitive adhesive of the present invention, the carboxylic acid ester preferably contains 31 or more carbon atoms in one molecule. The number of carbon atoms of the carboxylic acid ester is more preferably 36 or more. The upper limit of the number of carbon atoms of the carboxylic acid ester is, for example, 232 or less, preferably 92 or less.

前記化学式（Ｉ）中、
Ｒ^１は、炭化水素基、またはエーテル結合を含む基であり、前記炭化水素基および前記エーテル結合を含む基は、飽和でも不飽和でも良く、直鎖状でも分枝状でも環状でも良く、芳香環を含んでいても含んでいなくても良く、さらなる置換基で置換されていても置換されていなくても良く、
Ｒ^１は、さらに１または複数の（−ＣＯ−Ｏ−Ｒ^２）で置換されていても良く、Ｒ^２が複数の場合、各Ｒ^２は同一でも異なっていても良く、
Ｒ^２は、炭化水素基、またはエーテル結合を含む基であり、前記炭化水素基および前記エーテル結合を含む基は、飽和でも不飽和でも良く、直鎖状でも分枝状でも環状構造を含んでいても含んでいなくても良く、芳香環を含んでいても含んでいなくても良く、さらなる置換基で置換されていても置換されていなくても良く、同一または異なる分子（Ｉ）内において１または複数の他のＲ^２と一体化していても良く、
Ｒ^１およびＲ^２の少なくとも一方は、エーテル結合を含む基である。 In the pressure-sensitive adhesive of the present invention, the carboxylic acid ester is preferably a carboxylic acid ester represented by the following chemical formula (I).

In the chemical formula (I),
R ¹ is a hydrocarbon group or a group containing an ether bond, and the hydrocarbon group and the group containing an ether bond may be saturated or unsaturated, and may be linear, branched or cyclic, aromatic May or may not contain a ring, may or may not be substituted with a further substituent,
R ¹ may be further substituted with one or more (—CO—O—R ² ), and when R ² is plural, each R ² may be the same or different;
R ² is a hydrocarbon group or a group including an ether bond, and the hydrocarbon group and the group including an ether bond may be saturated or unsaturated, and may include a linear structure, a branched structure, or a cyclic structure. May or may not contain, may or may not contain an aromatic ring, may or may not be substituted with further substituents, and may be within the same or different molecules (I) And may be integrated with one or more other R ² ,
At least one of R ¹ and R ² is a group containing an ether bond.

In the chemical formula (I),
In R ¹ , the hydrocarbon group has 1 to 17 carbon atoms, the ether group-containing group has 1 to 200 carbon atoms,
In R ² , the hydrocarbon group preferably has 1 to 17 carbon atoms, and the group containing an ether bond preferably has 1 to 200 carbon atoms.

In the chemical formula (I), R ¹ is preferably a hydrocarbon group, and R ² is preferably a group containing an ether bond. In this case, the hydrocarbon group in R ¹ may be saturated or unsaturated, may be linear, branched or cyclic, may or may not contain an aromatic ring, and may be further substituted. It may or may not be substituted. In R ² , the group containing an ether bond may be saturated or unsaturated, may be linear, branched, or may not contain a cyclic structure, and may contain an aromatic ring. Or may be substituted with a further substituent or may be integrated with one or more other R ² groups.

In the chemical formula (I), R ¹ is more preferably a hydrogen atom, a linear or branched alkyl group, or a linear or branched unsaturated hydrocarbon group. In the chemical formula (I), R ¹ is a hydrogen atom, a linear or branched alkyl group having 1 to 17 carbon atoms, or a linear or branched unsaturated hydrocarbon group having 2 to 17 carbon atoms. More preferably it is. In the present invention, the “straight chain or branched unsaturated hydrocarbon group” is not particularly limited, and examples thereof include a straight chain or branched alkenyl group, a straight chain or branched alkynyl group, and the like.

In the chemical formula (I), R ¹ is methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group (sec-butyl group), tert-butyl group, n-pentyl group, isopentyl. Group (3-methylbutyl group), neopentyl group (2,2-dimethylpropyl group), n-hexyl group, n-heptyl group, 1-ethylheptyl group, n-octyl group, 2-ethylhexyl group, undecyl group (CH _{3 (CH 2) 10 -)} , a tridecyl group _{(CH 3 (CH 2) 12} -), a tetradecyl group _{(CH 3 (CH 2) 13} -), a pentadecyl group _{(CH 3 (CH 2) 14} -), a hexadecyl group _{(CH 3 (CH 2) 15} -), a heptadecyl group _{(CH 3 (CH 2) 16} -), cis-8- heptadecenyl _{(CH 3 - (CH 2)} 7 _{CH = CH (CH 2) 7} -), cis, cis-8,11- hept decadienyl group _{(CH 3 - (CH 2)} 3 (CH 2 CH = CH) 2 (CH 2) 7 -), 8 , 11,14-heptadecanetrienyl group (CH ₃ — (CH ₂ CH═CH) ₃ (CH ₂ ) ₇ —), or 5,8,11-heptadecatrienyl group (CH ₃ — (CH ₂ ) ₃ (CH ₂ CH═CH) ₃ (CH ₂ ) ₄ —) is preferred.

前記化学式（１）中、Ｒ^１１は、直鎖または分枝アルキル基であり、ｌは、正の整数であり、
前記化学式（２）中、Ｒ^１２は、直鎖または分枝アルキル基であり、ｍは、正の整数であり、
前記化学式（３）中、Ｒ^１３は、直鎖または分枝アルキル基であり、ｐは、正の整数であり、
前記化学式（４）中、Ｒ^１４は、直鎖または分枝アルキル基であり、ｑは、正の整数であり、
前記化学式（６）中、Ｒ^１６は、直鎖または分枝アルキル基であり、ｓは、正の整数であり、
前記化学式（１）〜（６）中、★印は、その位置で前記化学式（Ｉ）中のＯ原子に結合していることを表す。 In the chemical formula (I), R ² is preferably at least one of groups represented by the following chemical formulas (1) to (6).

In the chemical formula (1), R ¹¹ is a linear or branched alkyl group, l is a positive integer,
In the chemical formula (2), R ¹² is a linear or branched alkyl group, m is a positive integer,
In the chemical formula (3), R ¹³ is a linear or branched alkyl group, p is a positive integer,
In the chemical formula (4), R ¹⁴ is a linear or branched alkyl group, q is a positive integer,
In the chemical formula (6), R ¹⁶ is a linear or branched alkyl group, s is a positive integer,
In the chemical formulas (1) to (6), the asterisk (*) indicates that the atom is bonded to the O atom in the chemical formula (I) at that position.

In the chemical formula (1), R ¹¹ is more preferably a methyl group. In the chemical formula (1), l is more preferably 1-50.

In the chemical formula (2), R ¹² is more preferably a methyl group. Moreover, in said chemical formula (2), it is more preferable that m is 1-50.

In the chemical formula (3), R ¹³ is more preferably a methyl group. Moreover, in said chemical formula (3), it is more preferable that p is 1-50.

In the chemical formula (4), R ¹⁴ is more preferably a methyl group. Moreover, in said chemical formula (4), it is more preferable that q is 1-50.

In the chemical formula (6), R ¹⁶ is more preferably a methyl group. In the chemical formula (6), s is more preferably 1 to 50.

前記化学式（II）中、
Ｒ^１は、前記化学式（Ｉ）と同じであり、各Ｒ^１は同一でも異なっていても良く、
Ｒ^２０は、炭化水素基またはエーテル結合を含む基であり、前記炭化水素基および前記エーテル結合を含む基は、飽和でも不飽和でも良く、直鎖状でも分枝状でも環状構造を含んでいても含んでいなくても良く、芳香環を含んでいても含んでいなくても良く、さらなる置換基で置換されていても置換されていなくても良く、
Ｒ^１およびＲ^２０の少なくとも一方は、エーテル結合を含む基である。 The carboxylic acid ester represented by the chemical formula (I) may be represented by the following chemical formula (II) by combining two R ² together to form the atomic group R ²⁰ .

In the chemical formula (II),
R ¹ is the same as the chemical formula (I), and each R ¹ may be the same or different,
R ²⁰ is a hydrocarbon group or a group containing an ether bond, and the hydrocarbon group and the group containing an ether bond may be saturated or unsaturated, and include a linear structure, a branched structure, or a cyclic structure. May or may not contain, may or may not contain an aromatic ring, may or may not be substituted with a further substituent,
At least one of R ¹ and R ²⁰ is a group containing an ether bond.

In the chemical formula (II), in R ²⁰ , the number of carbon atoms of the hydrocarbon group is preferably 1-17, more preferably 2-9. ^Further, in ^{R 20,} carbon atoms group containing the ether bond is preferably from 1 to 200, more preferably from 36 to 92.

In the chemical formula (II), R ²⁰ is preferably a group containing an ether bond. In this case, the group containing an ether bond may be saturated or unsaturated, linear or branched, may or may not contain a cyclic structure, and may contain an aromatic ring. It may not be substituted, and it may or may not be substituted with a further substituent.

In the chemical formula (II), R ²⁰ is PEG (polyethylene glycol), PPG (polypropylene glycol), or EO / PO glycol (glycol which is a copolymer of ethylene oxide (EO) and propylene oxide (PO)). A group excluding the terminal hydroxyl group is preferred.

In the chemical formula (II), R ¹ is preferably a linear or branched alkyl group or an aralkyl group. In this case, the linear or branched alkyl group is preferably a linear or branched alkyl group having 2 to 5 carbon atoms. In the aralkyl group, the alkyl group moiety is a straight chain having 2 to 5 carbon atoms. A chain or branched alkyl group is preferred.

前記化学式（１１）中、ｌ_ａは、正の整数であり、
前記化学式（１２）中、ｍ_ａは、正の整数であり、
前記化学式（１３）中、ｐ_ａは、正の整数であり、
前記化学式（１４）中、ｑ_ａは、正の整数であり、
前記化学式（１５）中、ｒ_ａは、正の整数であり、
前記化学式（１６）中、ｓ_ａは、正の整数であり、
前記化学式（１１）〜（１６）中、★印は、その位置で前記化学式（II）中のＯ原子に結合していることを表す。 In the chemical formula (II), R ²⁰ is more preferably a group represented by any of the following chemical formulas (11) to (16).

In Chemical Formula (11), _{l a} is a positive integer,
In the chemical formula (12), m _a is a positive integer,
In Chemical Formula (13), _{p a} is a positive integer,
In the chemical formula (14), q _a is a positive integer,
In Chemical Formula (15), _{r a} is a positive integer,
In Chemical Formula (16), _{s a} is a positive integer,
In the chemical formulas (11) to (16), the asterisk (*) indicates that the atom is bonded to the O atom in the chemical formula (II) at that position.

In Chemical Formula (11), it is preferable _{l a} is 1 to 50. In the chemical formula (12), m _a is preferably 1 to 50. In Chemical Formula (13), it is preferable _{p a} is 1 to 50. In the chemical formula (14), q _a is preferably 1 to 50. In Chemical Formula (15), it is preferable _{r a} is 1 to 50. Further, in the above chemical formula (16), it is preferred _{s a} is 1 to 50.

  In the present invention, “alkyl” includes, for example, linear or branched alkyl. The number of carbon atoms in the alkyl is not particularly limited, and is, for example, 1 to 30, preferably 1 to 12, 1 to 6, or 1 to 4. Examples of the alkyl include, but are not limited to, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group and tert-butyl group, pentyl group, hexyl group, heptyl Group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, icosyl group and the like. The same applies to groups derived from alkyl groups and atomic groups (alkoxy groups and the like). The same applies to a group containing an alkyl group in the structure (alkylamino group, alkoxy group, etc.) or a group derived from an alkyl group (haloalkyl group, hydroxyalkyl group, aminoalkyl group, alkanoyl group, etc.).

  In the present invention, “alkenyl” includes, for example, linear or branched alkenyl. Examples of the alkenyl include those having one or more double bonds in the alkyl. The number of carbon atoms of the alkenyl is not particularly limited, and is the same as, for example, the alkyl, preferably 2 to 12 or 2 to 8. Examples of the alkenyl include vinyl, 1-propenyl, 2-propenyl, 1-butenyl, 2-butenyl, 3-butenyl, 1,3-butadienyl, 3-methyl-2-butenyl, and the like.

  In the present invention, “alkynyl” includes, for example, linear or branched alkynyl. Examples of the alkynyl include those having one or more triple bonds in the alkyl. The number of carbon atoms of the alkynyl is not particularly limited, and is the same as, for example, the alkyl, preferably 2 to 12 or 2 to 8. Examples of the alkynyl include ethynyl, propynyl, butynyl and the like. The alkynyl may further have one or more double bonds, for example.

  In the present invention, the “aromatic ring” includes, for example, aryl, heteroaryl and arylalkyl. The “cyclic structure” includes, for example, the aromatic ring, cycloalkyl, bridged cyclic hydrocarbon group, spiro hydrocarbon group, and cycloalkenyl.

  In the present invention, “aryl” includes, for example, a monocyclic aromatic hydrocarbon group and a polycyclic aromatic hydrocarbon group. The same applies to a group containing an aryl group in the structure (for example, an aralkyl group). Examples of the monocyclic aromatic hydrocarbon group include phenyl and the like. Examples of the polycyclic aromatic hydrocarbon group include 1-naphthyl, 2-naphthyl, 1-anthryl, 2-anthryl, 9-anthryl, 1-phenanthryl, 2-phenanthryl, 3-phenanthryl, 4-phenanthryl, 9- Examples include phenanthryl. Preferable examples include naphthyl such as phenyl, 1-naphthyl and 2-naphthyl.

  In the present invention, “heteroaryl” includes, for example, a monocyclic aromatic heterocyclic group and a condensed aromatic heterocyclic group. Examples of the heteroaryl include furyl (eg, 2-furyl, 3-furyl), thienyl (eg, 2-thienyl, 3-thienyl), pyrrolyl (eg, 1-pyrrolyl, 2-pyrrolyl, 3-pyrrolyl), Imidazolyl (eg: 1-imidazolyl, 2-imidazolyl, 4-imidazolyl), pyrazolyl (eg: 1-pyrazolyl, 3-pyrazolyl, 4-pyrazolyl), triazolyl (eg: 1,2,4-triazol-1-yl, 1,2,4-triazol-3-yl, 1,2,4-triazol-4-yl), tetrazolyl (eg 1-tetrazolyl, 2-tetrazolyl, 5-tetrazolyl), oxazolyl (eg 2-oxazolyl, 4-oxazolyl, 5-oxazolyl), isoxazolyl (eg, 3-isoxazolyl, 4-isoxazolyl, 5-isoxazolyl) Thiazolyl (eg: 2-thiazolyl, 4-thiazolyl, 5-thiazolyl), thiadiazolyl, isothiazolyl (eg: 3-isothiazolyl, 4-isothiazolyl, 5-isothiazolyl), pyridyl (eg: 2-pyridyl, 3-pyridyl, 4- Pyridyl), pyridazinyl (eg: 3-pyridazinyl, 4-pyridazinyl), pyrimidinyl (eg: 2-pyrimidinyl, 4-pyrimidinyl, 5-pyrimidinyl), furazanyl (eg: 3-furazinyl), pyrazinyl (eg: 2-pyrazinyl) Oxadiazolyl (eg 1,3,4-oxadiazol-2-yl), benzofuryl (eg 2-benzo [b] furyl, 3-benzo [b] furyl, 4-benzo [b] furyl, 5- Benzo [b] furyl, 6-benzo [b] furyl, 7-benzo [b] furyl), benzothienyl ( : 2-benzo [b] thienyl, 3-benzo [b] thienyl, 4-benzo [b] thienyl, 5-benzo [b] thienyl, 6-benzo [b] thienyl, 7-benzo [b] thienyl), Benzimidazolyl (eg, 1-benzimidazolyl, 2-benzimidazolyl, 4-benzoimidazolyl, 5-benzoimidazolyl), dibenzofuryl, benzoxazolyl, benzothiazolyl, quinoxalyl (eg, 2-quinoxalinyl, 5-quinoxalinyl, 6-quinoxalinyl), cinnolinyl (Example: 3-cinnolinyl, 4-cinnolinyl, 5-cinnolinyl, 6-cinnolinyl, 7-cinnolinyl, 8-cinnolinyl), quinazolyl (eg: 2-quinazolinyl, 4-quinazolinyl, 5-quinazolinyl, 6-quinazolinyl, 7- Quinazolinyl, 8-quinazolinyl ), Quinolyl (eg: 2-quinolyl, 3-quinolyl, 4-quinolyl, 5-quinolyl, 6-quinolyl, 7-quinolyl, 8-quinolyl), phthalazinyl (eg: 1-phthalazinyl, 5-phthalazinyl, 6-phthalazinyl) ), Isoquinolyl (eg, 1-isoquinolyl, 3-isoquinolyl, 4-isoquinolyl, 5-isoquinolyl, 6-isoquinolyl, 7-isoquinolyl, 8-isoquinolyl), prill, pteridinyl (eg, 2-pteridinyl, 4-pteridinyl, 6 -Pteridinyl, 7-pteridinyl), carbazolyl, phenanthridinyl, acridinyl (eg 1-acridinyl, 2-acridinyl, 3-acridinyl, 4-acridinyl, 9-acridinyl), indolyl (eg 1-indolyl, 2- In-drill, 3-in-drill, 4-in-drill, 5- N-dolyl, 6-indolyl, 7-indolyl), isoindolyl, phenazinyl (eg 1-phenazinyl, 2-phenazinyl) or phenothiazinyl (eg 1-phenothiazinyl, 2-phenothiazinyl, 3-phenothiazinyl, 4-phenothiazinyl) ) And the like.

  In the present invention, “cycloalkyl” is, for example, a cyclic saturated hydrocarbon group, and the number of carbon atoms is not particularly limited, but is, for example, 3-24 or 3-15. Examples of the cycloalkyl include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, a bridged cyclic hydrocarbon group, a spiro hydrocarbon group, and the like, preferably cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl. And a bridged cyclic hydrocarbon group.

  In the present invention, the “bridged cyclic hydrocarbon group” includes, for example, bicyclo [2.1.0] pentyl, bicyclo [2.2.1] heptyl, bicyclo [2.2.2] octyl and bicyclo [3. 2.1] octyl, tricyclo [2.2.1.0] heptyl, bicyclo [3.3.1] nonane, 1-adamantyl, 2-adamantyl and the like.

  In the present invention, examples of the “spiro hydrocarbon group” include spiro [3.4] octyl and the like.

  In the present invention, “cycloalkenyl” includes, for example, a cyclic unsaturated aliphatic hydrocarbon group, and the number of carbon atoms is, for example, 3-24 or 3-7. Examples of the group include cyclopropenyl, cyclobutenyl, cyclopentenyl, cyclohexenyl, cycloheptenyl, and the like, preferably cyclopropenyl, cyclobutenyl, cyclopentenyl, cyclohexenyl, and the like. The cycloalkenyl includes, for example, a bridged cyclic hydrocarbon group and a spiro hydrocarbon group having an unsaturated bond in the ring.

  In the present invention, “arylalkyl” includes, for example, benzyl, 2-phenethyl, naphthalenylmethyl and the like, and “cycloalkylalkyl” includes, for example, cyclohexylmethyl, adamantylmethyl and the like, and “hydroxyalkyl” "" Includes, for example, hydroxymethyl and 2-hydroxyethyl.

In the present invention, the “substituent” or “further substituent” is not particularly limited, and examples thereof include carboxy, halogen, and halogenated alkyl (eg, CF ₃ , CH ₂ CF ₃ , CH ₂ CCl ₃ ), Nitro, nitroso, cyano, alkyl (eg, methyl, ethyl, isopropyl, tert-butyl), alkenyl (eg, vinyl), alkynyl (eg, ethynyl), cycloalkyl (eg, cyclopropyl, adamantyl), cycloalkylalkyl ( Examples: cyclohexylmethyl, adamantylmethyl), cycloalkenyl (eg, cyclopropenyl), aryl (eg, phenyl, naphthyl), arylalkyl (eg, benzyl, phenethyl), heteroaryl (eg, pyridyl, furyl), heteroarylalkyl (Example: pyridylmethyl), f Telocyclyl (eg piperidyl), heterocyclylalkyl (eg morpholylmethyl), alkoxy (eg methoxy, ethoxy, propoxy, butoxy), perfluoroalkyl (eg CF ₃ ), halogenated alkoxy (eg OCF ₃ ), acyl, alkenyl Oxy (eg, vinyloxy, allyloxy), aryloxy (eg, phenyloxy), alkyloxycarbonyl (eg, methoxycarbonyl, ethoxycarbonyl, tert-butoxycarbonyl), arylalkyloxy (eg, benzyloxy), amino [alkylamino (Example: methylamino, ethylamino, dimethylamino), acylamino (eg, acetylamino, benzoylamino), arylalkylamino (eg, benzylamino, tritylamino), hydroxyamino No.], alkylaminoalkyl (eg, diethylaminomethyl), sulfamoyl, oxo and the like.

  In the present invention, “alkoxy” includes, for example, the alkyl-O— group, and examples thereof include methoxy, ethoxy, n-propoxy, isopropoxy, and n-butoxy, and “alkoxyalkyl” includes, for example, Examples thereof include methoxymethyl and the like, and “aminoalkyl” includes, for example, 2-aminoethyl and the like.

  In the present invention, “acyl” is not particularly limited, and examples thereof include formyl, acetyl, propionyl, isobutyryl, valeryl, isovaleryl, pivaloyl, hexanoyl, cyclohexanoyl, benzoyl, ethoxycarbonyl, and the like. The same applies to groups containing an acyl group in the structure (acyloxy group, alkanoyloxy group, etc.). In the present invention, the carbon number of the acyl group includes carbonyl carbon. For example, an alkanoyl group having 1 carbon atom (acyl group) refers to a formyl group.

  In the present invention, “halogen” refers to any halogen element, and examples thereof include fluorine, chlorine, bromine and iodine.

  In the present invention, “perfluoroalkyl” is not particularly limited, and examples thereof include a perfluoroalkyl group derived from a linear or branched alkyl group having 1 to 30 carbon atoms. More specifically, the “perfluoroalkyl” is, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl and tert-butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl. , Perfluoroalkyl groups derived from groups such as undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, icosyl and the like. The same applies to groups containing a perfluoroalkyl group in the structure (perfluoroalkylsulfonyl group, perfluoroacyl group, etc.).

  In the present invention, when the various groups described above are heterocycles or contain heterocycles, the “carbon number” includes the number of heteroatoms constituting the heterocycle.

  In the present invention, when an isomer is present in a substituent or the like, any isomer may be used unless otherwise specified. For example, a “naphthyl group” may be a 1-naphthyl group or a 2-naphthyl group, and a “propyl group” may be an n-propyl group or an isopropyl group.

前記化学式（１００１）および（１０１０）中、ｎは、正の整数である。 In the pressure-sensitive adhesive of the present invention, the carboxylic acid ester represented by the chemical formula (II) is at least one of a carboxylic acid ester represented by the following chemical formula (1001) and a carboxylic acid ester represented by the following chemical formula (1010). More preferably it is.

In the chemical formulas (1001) and (1010), n is a positive integer.

  In the chemical formulas (1001) and (1010), n is more preferably 1 to 50.

  Moreover, as described above, the pressure-sensitive adhesive sheet of the present invention is a pressure-sensitive adhesive sheet in which a pressure-sensitive adhesive layer is formed on at least one side of a substrate, and the pressure-sensitive adhesive layer is formed using the pressure-sensitive adhesive of the present invention. It is characterized by being. The pressure-sensitive adhesive sheet of the present invention is preferably a pressure-sensitive adhesive sheet that is used as a protective sheet for the image display surface by being attached to the image display surface of the image display device.

  The method for producing a pressure-sensitive adhesive sheet according to the present invention includes a coating step of coating the pressure-sensitive adhesive of the present invention on the pressure-sensitive adhesive layer-forming surface of the base material on which the pressure-sensitive adhesive layer is formed, and after the coating step, And a heating step of heating the pressure-sensitive adhesive on the pressure-sensitive adhesive layer forming surface.

  Moreover, as described above, the image display device of the present invention is an image display device in which the protective sheet of the image display device is attached to the image display surface, and the protective sheet is the pressure-sensitive adhesive sheet of the present invention. It is characterized by that.

  The pressure-sensitive adhesive, pressure-sensitive adhesive sheet, pressure-sensitive adhesive sheet manufacturing method, and image display device of the present invention can be described as, for example, the following (1) to (42), but are not limited thereto.

(1)
A pressure-sensitive adhesive containing the following components (A) and (B),

(A) Prepolymer of polyurethane (B) Crosslinking agent

The prepolymer (A) has a hydroxyl group,
The crosslinking agent (B) has an isocyanate group, and
The pressure-sensitive adhesive satisfies at least one of the following conditions [I] and [II].

[I] The prepolymer (A) is a polyurethane polyol obtained by reacting a polyol and a polyisocyanate, and the polyol does not contain a nitrogen atom,
And,
The crosslinking agent (B) includes the following (B1).

(B1) Biuret having three isocyanate groups in one molecule

[II] The crosslinking agent (B) contains at least one selected from the group consisting of the following (B2) to (B5).

(B2) allophanate having two isocyanate groups in one molecule (B3) uretdione having two isocyanate groups in one molecule (B4) urethane prepolymer having two isocyanate groups in one molecule (B5) in one molecule Biuret with two isocyanate groups

(2)
The said prepolymer (A) is a polyurethane polyol obtained by making a polyol and polyisocyanate react, and the said polyol does not contain a nitrogen atom, The adhesive as described in (1).

(3)
The prepolymer (A) is a polyurethane polyol obtained by reacting a polyol having three or more hydroxyl groups in one molecule with a polyisocyanate having two isocyanate groups in one molecule (1) or (2 ) The pressure-sensitive adhesive described.

(4)
The prepolymer (A) is a prepolymer obtained by reacting the following component (a1) with at least one selected from the group consisting of the following components (a2) to (a5) (1) to (3 ) The pressure-sensitive adhesive according to any one of

(A1) Polyol having three or more hydroxyl groups in one molecule (a2) Allophanate having two isocyanate groups in one molecule (a3) Uretodione having two isocyanate groups in one molecule (a4) Isocyanate in one molecule Urethane prepolymer having two groups (a5) Biuret having two isocyanate groups in one molecule

(5)
The pressure-sensitive adhesive according to (4), wherein the component (a1) is triol-type polypropylene glycol (PPG).

(6)
The pressure-sensitive adhesive according to (4) or (5), wherein the component (a4) is a urethane prepolymer obtained by reacting a polyol and a polyisocyanate.

(7)
The pressure-sensitive adhesive according to (6), wherein the polyisocyanate in the component (a4) is HDI (hexamethylene diisocyanate).

(8)
The pressure-sensitive adhesive according to (6) or (7), wherein the polyol in the component (a4) is a diol.

(9)
The pressure-sensitive adhesive according to (8), wherein the diol is a diol having an average molecular weight of 250 to 1800.

(10)
The pressure-sensitive adhesive according to (8), wherein the diol is a diol having an average molecular weight of 250 to 1600.

(11)
The pressure-sensitive adhesive according to any one of (8) to (10), wherein the component (a1) is triol-type polypropylene glycol (PPG).

(12)
The pressure-sensitive adhesive according to any one of (1) to (11), wherein the number of isocyanate groups of the cross-linking agent (B) is 0.4 to 1.0 in terms of molar ratio with respect to the number of hydroxyl groups of the prepolymer (A). .

(13)
The pressure-sensitive adhesive according to any one of (1) to (11), wherein the number of isocyanate groups of the crosslinking agent (B) is 0.4 to 0.8 in terms of molar ratio with respect to the number of hydroxyl groups of the prepolymer (A). .

(14)
The pressure-sensitive adhesive according to any one of (1) to (13), further comprising a carboxylic acid ester, wherein the carboxylic acid ester satisfies at least one of the following conditions [III] and [IV].

[III] The carboxylic acid ester contains an ether bond in the molecule.

[IV] The carboxylic acid ester contains 31 or more carbon atoms in one molecule.

(15)
The pressure-sensitive adhesive according to (14), wherein the carboxylic acid ester contains a plurality of ether bonds in one molecule.

(16)
The pressure-sensitive adhesive according to (14) or (15), wherein the carboxylic acid ester contains 36 or more carbon atoms in one molecule.

前記化学式（Ｉ）中、
Ｒ^１は、炭化水素基、またはエーテル結合を含む基であり、前記炭化水素基および前記エーテル結合を含む基は、飽和でも不飽和でも良く、直鎖状でも分枝状でも環状でも良く、芳香環を含んでいても含んでいなくても良く、さらなる置換基で置換されていても置換されていなくても良く、
Ｒ^１は、さらに１または複数の（−ＣＯ−Ｏ−Ｒ^２）で置換されていても良く、Ｒ^２が複数の場合、各Ｒ^２は同一でも異なっていても良く、
Ｒ^２は、炭化水素基、またはエーテル結合を含む基であり、前記炭化水素基および前記エーテル結合を含む基は、飽和でも不飽和でも良く、直鎖状でも分枝状でも環状構造を含んでいても含んでいなくても良く、芳香環を含んでいても含んでいなくても良く、さらなる置換基で置換されていても置換されていなくても良く、同一または異なる分子（Ｉ）内において１または複数の他のＲ^２と一体化していても良く、
Ｒ^１およびＲ^２の少なくとも一方は、エーテル結合を含む基である。 (17)
The pressure-sensitive adhesive according to any one of (14) to (16), wherein the carboxylic acid ester is a carboxylic acid ester represented by the following chemical formula (I).

In the chemical formula (I),
R ¹ is a hydrocarbon group or a group containing an ether bond, and the hydrocarbon group and the group containing an ether bond may be saturated or unsaturated, and may be linear, branched or cyclic, aromatic May or may not contain a ring, may or may not be substituted with a further substituent,
R ¹ may be further substituted with one or more (—CO—O—R ² ), and when R ² is plural, each R ² may be the same or different;
R ² is a hydrocarbon group or a group including an ether bond, and the hydrocarbon group and the group including an ether bond may be saturated or unsaturated, and may include a linear structure, a branched structure, or a cyclic structure. May or may not contain, may or may not contain an aromatic ring, may or may not be substituted with further substituents, and may be within the same or different molecules (I) And may be integrated with one or more other R ² ,
At least one of R ¹ and R ² is a group containing an ether bond.

(18)
In the chemical formula (I),
In R ¹ , the hydrocarbon group has 1 to 17 carbon atoms, the ether group-containing group has 1 to 200 carbon atoms,
In R ² , the hydrocarbon group has 1 to 17 carbon atoms, and the group containing the ether bond has 1 to 200 carbon atoms.
(17) The pressure-sensitive adhesive as described.

(19)
In the chemical formula (I),
R ¹ is a hydrocarbon group, and the hydrocarbon group may be saturated or unsaturated, linear, branched or cyclic, and may or may not contain an aromatic ring, May be substituted or unsubstituted with further substituents,
R ² is a group containing an ether bond, and the group containing an ether bond may be saturated or unsaturated, and may or may not contain a linear or branched or cyclic structure; It may or may not contain an aromatic ring, may be substituted with a further substituent or may not be substituted, and may be integrated with one or more other R ² .
(17) or the pressure-sensitive adhesive according to (18).

(20)
In the chemical formula (I),
The pressure-sensitive adhesive according to any one of (17) to (19), wherein R ¹ is a linear or branched alkyl group, or a linear or branched unsaturated hydrocarbon group.

(21)
In the chemical formula (I),
Any one of (17) to (19), wherein R ¹ is a linear or branched alkyl group having 1 to 17 carbon atoms, or a linear or branched unsaturated hydrocarbon group having 2 to 17 carbon atoms The adhesive as described.

(22)
In the chemical formula (I),
R ¹ is methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group (sec-butyl group), tert-butyl group, n-pentyl group, isopentyl group (3-methylbutyl group). , Neopentyl group (2,2-dimethylpropyl group), n-hexyl group, n-heptyl group, 1-ethylheptyl group, n-octyl group, 2-ethylhexyl group, undecyl group (CH ₃ (CH ₂ ) ₁₀ − ), Tridecyl group (CH ₃ (CH ₂ ) ₁₂ —), tetradecyl group (CH ₃ (CH ₂ ) ₁₃ —), pentadecyl group (CH ₃ (CH ₂ ) ₁₄ —), hexadecyl group (CH ₃ (CH ₂ )) ₁₅ -), a heptadecyl group _{(CH 3 (CH 2) 16} -), cis-8- heptadecenyl _{(CH 3 - (CH 2)} 7 CH = CH (CH 2 _{7 -), cis, cis-} 8,11- hept decadienyl group _{(CH 3 - (CH 2)} 3 (CH 2 CH = CH) 2 (CH 2) 7 -), 8,11,14- heptadecyl Cantrienyl group (CH ₃ — (CH ₂ CH═CH) ₃ (CH ₂ ) ₇ —) or 5,8,11-heptadecatrienyl group (CH ₃ — (CH ₂ ) ₃ (CH ₂ CH═ The pressure-sensitive adhesive according to any one of (17) to (19), which is CH) ₃ (CH ₂ ) ₄ —).

前記化学式（１）中、Ｒ^１１は、直鎖または分枝アルキル基であり、ｌは、正の整数であり、
前記化学式（２）中、Ｒ^１２は、直鎖または分枝アルキル基であり、ｍは、正の整数であり、
前記化学式（３）中、Ｒ^１３は、直鎖または分枝アルキル基であり、ｐは、正の整数であり、
前記化学式（４）中、Ｒ^１４は、直鎖または分枝アルキル基であり、ｑは、正の整数であり、
前記化学式（６）中、Ｒ^１６は、直鎖または分枝アルキル基であり、ｓは、正の整数であり、
前記化学式（１）〜（６）中、★印は、その位置で前記化学式（Ｉ）中のＯ原子に結合していることを表す。 (23)
In the chemical formula (I),
The pressure-sensitive adhesive according to any one of (17) to (22), wherein R ² is at least one of groups represented by the following chemical formulas (1) to (6).

In the chemical formula (1), R ¹¹ is a linear or branched alkyl group, l is a positive integer,
In the chemical formula (2), R ¹² is a linear or branched alkyl group, m is a positive integer,
In the chemical formula (3), R ¹³ is a linear or branched alkyl group, p is a positive integer,
In the chemical formula (4), R ¹⁴ is a linear or branched alkyl group, q is a positive integer,
In the chemical formula (6), R ¹⁶ is a linear or branched alkyl group, s is a positive integer,
In the chemical formulas (1) to (6), the asterisk (*) indicates that the atom is bonded to the O atom in the chemical formula (I) at that position.

(24)
In the chemical formula (1), R ¹¹ is a methyl group, l is 1 to 50,
In the chemical formula (2), R ¹² is a methyl group, m is 1 to 50,
In the chemical formula (3), R ¹³ is a methyl group, p is 1 to 50,
In the chemical formula (4), R ¹⁴ is a methyl group, q is 1 to 50,
In the chemical formula (6), the pressure-sensitive adhesive according to (23), wherein R ¹⁶ is a methyl group and s is 1 to 50.

前記化学式（II）中、
Ｒ^１は、前記化学式（Ｉ）と同じであり、各Ｒ^１は同一でも異なっていても良く、
Ｒ^２０は、炭化水素基またはエーテル結合を含む基であり、前記炭化水素基および前記エーテル結合を含む基は、飽和でも不飽和でも良く、直鎖状でも分枝状でも環状構造を含んでいても含んでいなくても良く、芳香環を含んでいても含んでいなくても良く、さらなる置換基で置換されていても置換されていなくても良く、
Ｒ^１およびＲ^２０の少なくとも一方は、エーテル結合を含む基である。 (25)
The carboxylic acid ester represented by the chemical formula (I) is represented by the following chemical formula (II) by combining two R ² together to form the atomic group R ²⁰ , (17) to (22) The adhesive in any one of.

In the chemical formula (II),
R ¹ is the same as the chemical formula (I), and each R ¹ may be the same or different,
R ²⁰ is a hydrocarbon group or a group containing an ether bond, and the hydrocarbon group and the group containing an ether bond may be saturated or unsaturated, and include a linear structure, a branched structure, or a cyclic structure. May or may not contain, may or may not contain an aromatic ring, may or may not be substituted with a further substituent,
At least one of R ¹ and R ²⁰ is a group containing an ether bond.

(26)
In R ^20, the number of carbon atoms of the hydrocarbon group is a 1 to 17 carbon atoms in the group containing the ether bond is 1 to 200,
(25) The adhesive as described.

(27)
R ²⁰ is a group containing an ether bond, and the group containing an ether bond may be saturated or unsaturated, and may or may not contain a linear structure, a branched structure, or a cyclic structure; May or may not contain an aromatic ring, may or may not be substituted with a further substituent,
(25) or the adhesive as described in (26).

(28)
R ²⁰ is a group obtained by removing hydroxyl groups at both ends in PEG (polyethylene glycol), PPG (polypropylene glycol), or EO / PO glycol (glycol which is a copolymer of ethylene oxide (EO) and propylene oxide (PO)). The adhesive according to (25) or (26).

(29)
The pressure-sensitive adhesive according to any one of (25) to (28), wherein R ¹ is a linear or branched alkyl group or an aralkyl group.

(30)
The linear or branched alkyl group is a linear or branched alkyl group having 2 to 5 carbon atoms, and in the aralkyl group, the alkyl group portion is a linear or branched alkyl group having 2 to 5 carbon atoms. A pressure-sensitive adhesive according to (29).

前記化学式（１１）中、ｌ_ａは、正の整数であり、
前記化学式（１２）中、ｍ_ａは、正の整数であり、
前記化学式（１３）中、ｐ_ａは、正の整数であり、
前記化学式（１４）中、ｑ_ａは、正の整数であり、
前記化学式（１５）中、ｒ_ａは、正の整数であり、
前記化学式（１６）中、ｓ_ａは、正の整数であり、
前記化学式（１１）〜（１６）中、★印は、その位置で前記化学式（II）中のＯ原子に結合していることを表す。 (31)
In the chemical formula (II),
The pressure-sensitive adhesive according to any one of (25) to (30), wherein R ²⁰ is a group represented by any one of the following chemical formulas (11) to (16).

In Chemical Formula (11), _{l a} is a positive integer,
In the chemical formula (12), m _a is a positive integer,
In Chemical Formula (13), _{p a} is a positive integer,
In the chemical formula (14), q _a is a positive integer,
In Chemical Formula (15), _{r a} is a positive integer,
In Chemical Formula (16), _{s a} is a positive integer,
In the chemical formulas (11) to (16), the asterisk (*) indicates that the atom is bonded to the O atom in the chemical formula (II) at that position.

(32)
In Chemical Formula (11), _{l a} is 1 to 50,
In Chemical Formula (12), _{m a} is 1 to 50,
In Chemical Formula (13), _{p a} is 1 to 50,
In the chemical formula (14), q _a is 1 to 50,
In Chemical Formula (15), _{r a} is 1 to 50,
In Chemical Formula (16), _{s a} is 1 to 50, the pressure-sensitive adhesive described (31).

前記化学式（１００１）および（１０１０）中、ｎは、正の整数である。 (33)
The adhesive according to (25), wherein the carboxylic acid ester represented by the chemical formula (II) is at least one of a carboxylic acid ester represented by the following chemical formula (1001) and a carboxylic acid ester represented by the following chemical formula (1010). Agent.

In the chemical formulas (1001) and (1010), n is a positive integer.

(34)
The adhesive according to (33), wherein n is 1 to 50 in the chemical formulas (1001) and (1010).

(35)
A polyurethane prepolymer used for producing the pressure-sensitive adhesive according to any one of (1) to (34), comprising the component (A).

(36)
A crosslinking agent comprising the component (B) and used for producing the pressure-sensitive adhesive according to any one of (1) to (34).

(37)
A kit for producing a pressure-sensitive adhesive comprising the components (A) and (B) and capable of producing the pressure-sensitive adhesive according to any one of (1) to (34) by mixing the components.

(38)
An adhesive sheet having an adhesive layer formed on at least one side of a substrate,
The pressure-sensitive adhesive sheet, wherein the pressure-sensitive adhesive layer is a pressure-sensitive adhesive layer formed using the pressure-sensitive adhesive according to any one of (1) to (34).

(39)
The pressure-sensitive adhesive sheet according to (38), which is used as a surface protective sheet.

(40)
The pressure-sensitive adhesive sheet according to (38) or (39), which is used as a protective sheet for the image display surface by being attached to the image display surface of the image display device.

(41)
A coating step of coating the pressure-sensitive adhesive according to any one of (1) to (34) on the pressure-sensitive adhesive layer-forming surface of the base material on which the pressure-sensitive adhesive layer is formed;
A heating step of heating the pressure-sensitive adhesive on the pressure-sensitive adhesive layer forming surface after the coating step,
(38) The manufacturing method of the adhesive sheet in any one of (40).

(42)
An image display device in which a protective sheet of the image display device is attached to an image display surface,
The image display device, wherein the protective sheet is the pressure-sensitive adhesive sheet described in (40).

  Hereinafter, embodiments of the present invention will be described more specifically. However, the present invention is not limited to the following embodiments.

[1. Adhesive]
As described above, the adhesive of the present invention is
A pressure-sensitive adhesive containing the following components (A) and (B),

(A) Prepolymer of polyurethane (B) Crosslinking agent

The prepolymer (A) has a hydroxyl group,
The crosslinking agent (B) has an isocyanate group, and
The pressure-sensitive adhesive satisfies at least one of the following conditions [I] and [II].

[I] The prepolymer (A) is a polyurethane polyol obtained by reacting a polyol and a polyisocyanate, and the polyol does not contain a nitrogen atom,
And,
The crosslinking agent (B) includes the following (B1).

(B1) Biuret having three isocyanate groups in one molecule

[II] The crosslinking agent (B) contains at least one selected from the group consisting of the following (B2) to (B5).

(B2) allophanate having two isocyanate groups in one molecule (B3) uretdione having two isocyanate groups in one molecule (B4) urethane prepolymer having two isocyanate groups in one molecule (B5) in one molecule Biuret with two isocyanate groups

[1-1. Said components (A) and (B)]
The prepolymer (A) is not particularly limited, but as described above, a prepolymer obtained by reacting at least one selected from the group consisting of the following component (a1) and the following components (a2) to (a5). A polymer is preferable, and a prepolymer obtained by reacting at least one selected from the group consisting of the following components (a2) to (a4) is more preferable. In this case, the raw material of the prepolymer (A) may contain components other than the following components (a1) to (a5) or (a1) to (a4), and may contain a diol, for example. .

(A1) Polyol having three or more hydroxyl groups in one molecule (a2) Allophanate having two isocyanate groups in one molecule (a3) Uretodione having two isocyanate groups in one molecule (a4) Isocyanate in one molecule Urethane prepolymer having two groups (a5) Biuret having two isocyanate groups in one molecule

  The component (a1), that is, a polyol having 3 or more hydroxyl groups in one molecule (also referred to as trivalent or higher or trifunctional or higher) is not particularly limited, and examples thereof include triol, tetraol, and pentaol. One kind or plural kinds of polyols may be used. The component (a1) is particularly preferably triol from the viewpoint that it is difficult to gel. For example, as mentioned above, the raw material of the prepolymer (A) may contain a diol in addition to the component (a1).

  The component (a1) can be selected from, for example, various known polyols. Specifically, the component (a1) is selected from, for example, polyether polyol (a1-1), polyester polyol (a1-2), polycarbonate polyol (a1-3), polyolefin polyol (a1-4), and the like. be able to. These may be used alone or in combination of two or more. The component (a1) may be a copolymer. Specifically, the copolymer may be, for example, a copolymer in which a lactone monomer is added to the end of a polyether polyol. In addition, the component (a1) particularly preferably contains a polypropylene glycol (PPG) polyol having a valence of 3 or more (having 3 or more hydroxyl groups).

  Further, as described above, the prepolymer (A) is obtained by reacting the component (a1), that is, a polyol having three or more hydroxyl groups, and the component (a4), that is, a urethane prepolymer having two isocyanate groups. More preferred are prepolymers. In this case, the component (a1) is more preferably triol, and further preferably triol-type polypropylene glycol (PPG).

The component (a4), that is, the urethane prepolymer having two isocyanate groups in one molecule may be, for example, a urethane prepolymer having an isocyanate group at at least one terminal (preferably both terminals). Moreover, it is preferable that the said component (a4) is a urethane prepolymer obtained by making the following component (a4-1) and the following component (a4-2) react.

(A4-1) Polyol (a4-2) Polyisocyanate

  More preferably, the polyol (a4-1) is a diol, and the polyisocyanate (a4-2) is a bifunctional polyisocyanate (also referred to as polyisocyanate having two isocyanate groups or diisocyanate). Moreover, although the said component (a4) does not need to have a hydroxyl group, it does not need to have a hydroxyl group. The hydroxyl group may be, for example, a (unreacted) hydroxyl group derived from the polyol (a4-1). For example, the raw material of the said component (a4) may contain components other than the said components (a4-1) and (a4-2), for example, may contain arbitrary chain extenders.

  As described above, the polyol (a4-1) is preferably a diol, but may be a trivalent (trifunctional) or higher polyol, or may contain a diol and a trivalent or higher polyol. Specifically, the component (a4-1) includes, for example, polyether polyol (a4-1-1), polyester polyol (a4-1-2), polycarbonate polyol (a4-1-3), polyolefin polyol ( a4-1-4) or the like. These may be used alone or in combination of two or more. The component (a4-1) may be a copolymer. Specifically, the copolymer may be, for example, a copolymer in which a lactone monomer is added to the end of a polyether polyol.

  In addition, the specific structure of the component (a4) is not particularly limited, but may be a compound represented by the chemical formula (B4), for example.

  In the pressure-sensitive adhesive of the present invention, as described above, the crosslinking agent (B) contains (B1), or at least one selected from the group consisting of (B2) to (B5). Including. Or while the said crosslinking agent (B) contains the said (B1), it may further contain at least one selected from the group which consists of said (B2)-(B5). Moreover, it is preferable that at least one selected from the group consisting of (B2) to (B5) is at least one selected from the group consisting of (B2) to (B4). The structures (B1) to (B5) are not particularly limited, and are, for example, as described above. The structure, raw material, etc. of (B4) may be the same as (a4), for example. Commercially available products may be used as the urethane prepolymer represented by (a4) or (B4), and specific examples include Duranate D-101 (trade name) manufactured by Asahi Kasei Chemicals Corporation.

  In addition, from the viewpoint of preventing unnecessary crosslinking (curing) during storage, for example, the prepolymer (A) and the crosslinking agent (B) may be stored without being mixed. In this case, the pressure-sensitive adhesive of the present invention may be produced by mixing the prepolymer (A) and the cross-linking agent (B), for example, in the “coating step” during the production of the pressure-sensitive adhesive sheet. Alternatively, for example, the pressure-sensitive adhesive of the present invention is described later so that unnecessary cross-linking (curing) during storage of the pressure-sensitive adhesive can be prevented even if the prepolymer (A) and the cross-linking agent (B) are mixed. It may contain a crosslinking inhibitor (crosslinking retarder).

  As described above, the prepolymer (A) is more preferably a polyurethane polyol synthesized from a polyol and a polyisocyanate. Although the content rate of the said polyurethane polyol is not specifically limited, Preferably it is 70 to 80 weight% with respect to the total weight of the adhesive of this invention, More preferably, it is 30 to 70 weight%, More preferably, it is 40 to 60 weight%. is there. In this case, the pressure-sensitive adhesive of the present invention may or may not contain polyisocyanate as a cross-linking agent. When the pressure-sensitive adhesive of the present invention contains the polyisocyanate as a crosslinking agent, the content is not particularly limited, but is preferably 0.5 to 70% by weight, more preferably, based on the total weight of the pressure-sensitive adhesive of the present invention. Is 2 to 10% by weight. In addition, although the kind etc. of the said polyol and polyisocyanate are not specifically limited, For example, it is as above-mentioned. Also in “2. Method for producing pressure-sensitive adhesive” described later, the types of the polyol and polyisocyanate are described together with an example of the method for producing the pressure-sensitive adhesive of the present invention.

[1-2. Components other than the components (A) and (B)]
The pressure-sensitive adhesive of the present invention may or may not contain components other than the components (A) and (B) as appropriate. The pressure-sensitive adhesive of the present invention includes a solvent, an antioxidant, a crosslinking inhibitor (crosslinking retarder), a filler, a colorant, an ultraviolet absorber, and an antifoam as components other than the components (A) and (B). Agents, light stabilizers, etc. may or may not be included. Although those kinds etc. are not specifically limited, For example, you may follow the same as that of a general adhesive, or it. Although it does not specifically limit as said ultraviolet absorber, For example, ultraviolet absorbers, such as a benzophenone series, a benzotriazole series, and a triazine series, are mentioned. Although it does not specifically limit as said antifoamer, For example, antifoamers, such as a silicone type and a mineral oil type, are mentioned. Although it does not specifically limit as said light stabilizer, For example, light stabilizers, such as a hindered amine type, are mentioned. The solvent, the antioxidant, and the crosslinking inhibitor (crosslinking retarder) will be described together with an example of the method for producing the pressure-sensitive adhesive of the present invention in “2. Moreover, the adhesive of this invention may contain the plasticizer as components other than the said component (A) and (B), for example, and does not need to contain it. By including the plasticizer, for example, an effect of suppressing an increase in adhesive strength with time can be obtained. The “increased adhesive strength with time” is a phenomenon in which, when an adhesive is applied to the surface of an adherend (for example, in the form of an adhesive sheet), the adhesive strength to the adherend surface increases with the passage of time after application. Say. By suppressing this increase in adhesive strength over time, for example, the removability of the pressure-sensitive adhesive or pressure-sensitive adhesive sheet is further improved, and the stain resistance to the adherend surface is further improved. The plasticizer may or may not contain, for example, a carboxylic acid ester that satisfies at least one of the conditions [III] and [IV], or may contain other plasticizers. You don't have to leave.

As described above, the pressure-sensitive adhesive of the present invention preferably contains a carboxylic acid ester that satisfies at least one of the following conditions [III] and [IV] as other components than the components (A) and (B).

[III] The carboxylic acid ester contains an ether bond in the molecule.

[IV] The carboxylic acid ester contains 31 or more carbon atoms in one molecule.

  Here, the manufacturing method of the pressure-sensitive adhesive sheet according to the present invention, as described above, a coating step of applying the pressure-sensitive adhesive of the present invention to the pressure-sensitive adhesive layer-forming surface on which the pressure-sensitive adhesive layer is formed, It is the manufacturing method of the adhesive sheet of the said invention including the heating process of heating the said adhesive on the said adhesion layer formation surface after the said coating process. The heating temperature in the heating step is not particularly limited and can be set as appropriate. It is preferable that the heating temperature is not too low from the viewpoint of preventing curing (crosslinking reaction) of the adhesive layer and preventing the adhesive layer from protruding from the end of the substrate. When drying (removing the solvent) together with heating, it is preferable that the heating temperature is not too low from the viewpoint of preventing a decrease in productivity due to the time required for drying. On the other hand, it is preferable that the heating temperature is not too high from the viewpoint of not reducing the adhesion of the adhesive layer to the substrate.

  When the pressure-sensitive adhesive of the present invention contains a carboxylic acid ester that satisfies at least one of the above conditions [III] and [IV], for example, the heating temperature after applying the pressure-sensitive adhesive to a substrate is made higher. Thus, the productivity is further improved, and the adhesion between the substrate and the adhesive layer is further improved. In addition, for example, it is possible to provide a pressure-sensitive adhesive that can prevent repellency and protrusion to the base material and has good adhesion between the base material and the pressure-sensitive adhesive layer. Although the reason (mechanism) is not clear, for example, the reason that the carboxylic acid ester relieves the internal stress of the pressure-sensitive adhesive can be considered. However, this mechanism is speculation and does not limit the present invention.

As described above, the carboxylic acid ester is preferably, for example, a carboxylic acid ester represented by the following chemical formula (I). Moreover, as described above, in the chemical formula (I), R ² is preferably at least one of groups represented by the following chemical formulas (1) to (6). R ¹ and R ^{2 in} the following chemical formula (I), R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁶ , l, m, p, q and s in the following chemical formulas (1) to (6) are: As described above.

In addition, the carboxylic acid moiety (R ¹ —CO—O—) of the fatty acid ester represented by the chemical formula (I) has, for example, a monobasic acid or polybasic acid having 8 to 18 carbon atoms, or a carbon number. 14-18 unsaturated fatty acid etc. are mentioned. Examples of the monobasic acid or polybasic acid having 8 to 18 carbon atoms include lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, adipic acid, sebacic acid, trimellitic acid, and trimellitic acid. Examples of the unsaturated fatty acid having 14 to 18 carbon atoms include myristoleic acid, oleic acid, linoleic acid, linolenic acid, isopalmitic acid, and isostearic acid.

  Specific examples of the fatty acid ester represented by the chemical formula (I) include compounds (101) to (112) shown in Table 1 below.

As described above, the carboxylic acid ester is preferably a carboxylic acid ester represented by the following chemical formula (II), for example. Moreover, as described above, in the chemical formula (II), R ² is preferably a group represented by any of the following chemical formulas (11) to (16). Following chemical formula (II) ^{R 1} and ^{R 20} in, _l a in the following chemical formula _{(11) ~ (16),} m a, p a, q a, r a, and _{s a} are as described above.

  Specific examples of the fatty acid ester represented by the chemical formula (II) include compounds (1001) to (1012) shown in Table 2 below.

  Further, in the pressure-sensitive adhesive of the present invention, the content of the carboxylic acid ester is not particularly limited. However, the viewpoint of developing better base material adhesion, and excellent wettability (wet spreading property) to the adherend. From the viewpoint of developing the content, 5% by weight or more is preferable with respect to the total weight of the pressure-sensitive adhesive of the present invention. The content of the carboxylic acid ester is preferably 50% by weight or less with respect to the total weight of the pressure-sensitive adhesive of the present invention from the viewpoint of preventing the applied pressure-sensitive adhesive from protruding from the end of the substrate. The content of the carboxylic acid ester is more preferably 10 to 30% by weight, still more preferably 15 to 25% by weight, based on the total weight of the pressure-sensitive adhesive of the present invention.

[2. Manufacturing method of adhesive]
The method for producing the pressure-sensitive adhesive of the present invention is not particularly limited, and for example, a general method for producing a pressure-sensitive adhesive may be referred to, for example, the above-mentioned Patent Document 1 or 2 may be referred to. Hereinafter, the production method of the pressure-sensitive adhesive of the present invention will be described with examples.

  First, the component (A), that is, a polyurethane polyol (a polyurethane prepolymer having a hydroxyl group) is produced (synthesized). That is, first, a polyol, polyisocyanate, solvent, and a catalyst as necessary are placed in a reaction vessel, and the reaction is carried out with heating and stirring. Although the usage-amount of the said polyol is not specifically limited, It is 20 to 80 weight% with respect to the weight of the adhesive after manufacture, Preferably it is 40 to 60 weight%. Although the usage-amount of the said polyisocyanate is not specifically limited, It is 0.5 to 10 weight% with respect to the weight of the adhesive after manufacture, Preferably it is 1 to 5 weight%. Although the usage-amount of the said solvent is not specifically limited, It is 10 to 50 weight% with respect to the weight of the adhesive after manufacture, Preferably it is 20 to 40 weight%. The catalyst may not be used, but is preferably used from the viewpoint of smooth progress of the reaction. When using the said catalyst, the usage-amount is although it does not specifically limit, For example, it is 0.001-0.1 weight% with respect to the weight of the adhesive after manufacture. Although the reaction temperature of the said reaction is not specifically limited, For example, 30-80 degreeC, More preferably, it is 40-60 degreeC. Although the reaction time of the said reaction is not specifically limited, For example, it is 0.5-15 hr, More preferably, it is 0.5-4 hr, More preferably, it is 1-3 hr. In this way, a polyurethane polyol (A) -containing composition can be synthesized.

  In the synthesis of the polyurethane polyol (A) -containing composition, for example, (1) polyester polyol, polyether polyol, catalyst, method of charging polyisocyanate into the whole flask, and (2) polyester polyol, polyether polyol A method of adding the catalyst by dropping the polyisocyanate into the flask is possible. (1) is simpler, but (2) is easier to control the reaction, so it can be used as needed.

  Furthermore, the above-mentioned polyurethane polyol (A) -containing composition is added with the above-mentioned crosslinking agent (B) and, if necessary, a solvent, an antioxidant and a crosslinking inhibitor (crosslinking retarder), the fatty acid ester, etc. Stir until. In this way, the pressure-sensitive adhesive of the present invention can be obtained. Although the usage-amount of the said crosslinking agent (B) is not specifically limited, Preferably it is 0.5-20 weight% with respect to the total weight of the said adhesive of this invention, More preferably, it is 1-10 weight%. Or the usage-amount of the said crosslinking agent (B) becomes like this. Preferably it is 0.8-30 weight% with respect to the total weight of the said polyurethane polyol (A) contained in the said adhesive of this invention, More preferably, it is 3-16. % By weight. The amount of the fatty acid ester used is not particularly limited and may or may not be used, but when used, for example, 5 to 50% by weight, preferably based on the weight of the pressure-sensitive adhesive after production. 10 to 30% by weight. The solvent may not be used, but is preferably used from the viewpoint of smooth mixing of the polyurethane polyol (A) -containing composition, the crosslinking agent, and other components as necessary. When the catalyst is used, the amount used is not particularly limited, but is 0.001 to 0.1% by weight, preferably 0.01 to 0.05% by weight, based on the weight of the pressure-sensitive adhesive after production. is there. The antioxidant is not necessarily used, but is preferably used. When the antioxidant is used, the amount used is not particularly limited, but is 0.05 to 1% by weight, preferably 0.1 to 0.6% by weight, based on the weight of the pressure-sensitive adhesive after production. is there.

  The polyol is not particularly limited. For example, as described above, the polyol may be bifunctional (divalent, that is, having two hydroxyl groups in one molecule) or trifunctional or more (trivalent or more, that is, having three or more hydroxyl groups in the molecule). Trifunctional or higher is preferable, and trifunctional is particularly preferable. Moreover, only one kind of the polyol may be used or a plurality of kinds may be used in combination. Although the said polyol is not specifically limited, For example, one or both of polyester polyol and polyether polyol may be sufficient.

  The polyester polyol is not particularly limited, and for example, a known polyester polyol may be used. Examples of the acid component of the polyester polyol include terephthalic acid, adipic acid, azelaic acid, sebacic acid, phthalic anhydride, isophthalic acid, trimellitic acid, and the like. Examples of the glycol component of the polyester polyol include ethylene glycol, propylene glycol, diethylene glycol, butylene glycol, 1,6-hexane glycol, 3-methyl-1,5-pentanediol, 3,3′-dimethylol heptane, poly Examples thereof include oxyethylene glycol, polyoxypropylene glycol, 1,4-butanediol, neopentyl glycol, and butylethylpentanediol. Examples of the polyol component of the polyester polyol include glycerin, trimethylolpropane, pentaerythritol and the like. Other examples include polyester polyols obtained by ring-opening polymerization of lactones such as polycaprolactone, poly (β-methyl-γ-valerolactone), and polyvalerolactone.

  The molecular weight of the polyester polyol is not particularly limited, and can be used from a low molecular weight to a high molecular weight. Preferably, a polyester polyol having a number average molecular weight of 500 to 5,000 is used. If the number average molecular weight is 500 or more, it is easy to prevent gelation due to too high reactivity. Moreover, if a number average molecular weight is 5,000 or less, it will be easy to prevent the fall of reactivity and the fall of the cohesive force of polyurethane polyol itself. The polyester polyol may or may not be used, but the amount used is, for example, 10 to 90 mol% in the polyol constituting the polyurethane polyol.

  Moreover, the said polyether polyol is not specifically limited, For example, a well-known polyether polyol may be sufficient. Specifically, the polyether polyol is, for example, an oxirane such as ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran using a low molecular weight polyol such as water, propylene glycol, ethylene glycol, glycerin, trimethylolpropane or the like as an initiator. It may be a polyether polyol obtained by polymerizing a compound. More specifically, the polyether polyol may have two or more functional groups such as polypropylene glycol, polyethylene glycol, polytetramethylene glycol, and the like. The molecular weight of the polyether polyol is not particularly limited, and can be used from a low molecular weight to a high molecular weight. Preferably, a polyether polyol having a number average molecular weight of 1,000 to 15,000 is used. If the number average molecular weight is 1,000 or more, it is easy to prevent gelation due to too high reactivity. Moreover, if molecular weight is 15,000 or less, it will be easy to prevent the fall of reactivity and the fall of the cohesion force of polyurethane polyol itself. The polyether polyol may or may not be used, but the amount used when used is, for example, 20 to 80 mol% in the polyol constituting the polyurethane polyol.

  If necessary, the polyether polyol may be partially blended with glycols such as ethylene glycol, 1,4-butanediol, neopentyl glycol, butylethylpentanediol, glycerin, trimethylolpropane, pentaerythritol, ethylenediamine, N -It may be used in combination with polyamines such as aminoethylethanolamine, isophoronediamine and xylylenediamine.

  As described above, the polyol may be a bifunctional polyether polyol (having two hydroxyl groups in one molecule), but is preferably trifunctional or more (having three or more hydroxyl groups in one molecule). In particular, the use of a part or all of a polyol having a number average molecular weight of 1,000 to 15,000 and a trifunctional or higher functionality makes it easier to balance the adhesive force and the removability. If the number average molecular weight is 1,000 or more, it is easy to prevent gelation due to too high reactivity of the tri- or higher functional polyol. Moreover, if the number average molecular weight is 15,000 or less, it is easy to prevent a decrease in reactivity of a tri- or higher functional polyol and a decrease in cohesive strength of the polyurethane polyol itself. More preferably, a part or all of a polyol having a number average molecular weight of 2,500 to 3,500 and having a functionality of 3 or more is used.

  Although it does not specifically limit as said polyisocyanate (organic polyisocyanate compound), For example, well-known aromatic polyisocyanate, aliphatic polyisocyanate, araliphatic polyisocyanate, alicyclic polyisocyanate etc. are mentioned. Moreover, polyisocyanate may be used alone or in combination of two or more.

  Examples of the aromatic polyisocyanate include 1,3-phenylene diisocyanate, 4,4′-diphenyl diisocyanate, 1,4-phenylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2, 6-tolylene diisocyanate, 4,4′-toluidine diisocyanate, 2,4,6-triisocyanate toluene, 1,3,5-triisocyanate benzene, dianisidine diisocyanate, 4,4′-diphenyl ether diisocyanate, 4,4 ′ , 4 "-triphenylmethane triisocyanate and the like.

  Examples of the aliphatic polyisocyanate include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, and dodecamethylene diisocyanate. 2,4,4-trimethylhexamethylene diisocyanate and the like.

  Examples of the araliphatic polyisocyanate include ω, ω′-diisocyanate-1,3-dimethylbenzene, ω, ω′-diisocyanate-1,4-dimethylbenzene, ω, ω′-diisocyanate-1,4- Examples include diethylbenzene, 1,4-tetramethylxylylene diisocyanate, 1,3-tetramethylxylylene diisocyanate, and the like.

  Examples of the alicyclic polyisocyanate include 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate, 1,3-cyclopentane diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, methyl- 2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 4,4′-methylenebis (cyclohexyl isocyanate), 1,4-bis (isocyanate methyl) cyclohexane, 1,4-bis (isocyanate methyl) cyclohexane, etc. Can be mentioned.

  Further, a trimethylolpropane adduct of the above polyisocyanate, a burette reacted with water, a trimer having an isocyanurate ring, and the like can also be used in combination.

  As the polyisocyanate, 4,4′-diphenylmethane diisocyanate, hexamethylene diisocyanate, 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate (isophorone diisocyanate) and the like are preferable.

  The catalyst is not particularly limited, and for example, a known catalyst can be used. Examples of the catalyst include tertiary amine compounds and organometallic compounds.

  Examples of the tertiary amine compound include triethylamine, triethylenediamine, 1,8-diazabicyclo (5,4,0) -undecene-7 (DBU), and the like.

  Examples of the organometallic compound include a tin compound and a non-tin compound. Examples of the tin compound include dibutyltin dichloride, dibutyltin oxide, dibutyltin dibromide, dibutyltin dimaleate, dibutyltin dilaurate (DBTDL), dibutyltin diacetate, dibutyltin sulfide, tributyltin sulfide, tributyltin oxide, Examples include tributyltin acetate, triethyltin ethoxide, tributyltin ethoxide, dioctyltin oxide, tributyltin chloride, tributyltin trichloroacetate, and tin 2-ethylhexanoate. Examples of the non-tin compound include titanium-based compounds such as dibutyltitanium dichloride, tetrabutyltitanate, butoxytitanium trichloride, lead-based compounds such as lead oleate, lead 2-ethylhexanoate, lead benzoate, lead naphthenate, Iron such as iron 2-ethylhexanoate and iron acetylacetonate, cobalt such as cobalt benzoate and cobalt 2-ethylhexanoate, zinc such as zinc naphthenate and zinc 2-ethylhexanoate, zirconium naphthenate, etc. Is mentioned.

  When these catalysts are used, for example, in a system in which two types of polyols, a polyester polyol and a polyether polyol, exist, gelation occurs in a single catalyst system or the reaction solution becomes cloudy due to the difference in reactivity. Is likely to occur. In such a case, for example, by using two or more kinds of catalysts in combination, the reaction rate, the selectivity of the catalyst, and the like can be controlled, and these problems can be solved. Examples of the combination include tertiary amine / organometallic, tin / non-tin, tin / tin, etc., preferably tin / tin, and more preferably dibutyltin dilaurate and 2- It is a combination of tin ethylhexanoate. The mixing ratio is not particularly limited, but for example, 2-ethylhexanoic acid tin / dibutyltin dilaurate is less than 1 by weight, and preferably 0.2 to 0.6. If the blending ratio is less than 1, it is easy to prevent gelation due to the balance of catalyst activity. Although the usage-amount of these catalysts is not specifically limited, For example, it is 0.01 to 1.0 weight% with respect to the total amount of a polyol and organic polyisocyanate.

  When using the said catalyst, the reaction temperature of the said polyurethane polyol synthesis | combination is preferably less than 100 degreeC, More preferably, it is 40 to 60 degreeC. If it is less than 100 degreeC, it is easy to control reaction rate and a crosslinked structure, and it is easy to obtain the polyurethane polyol which has predetermined molecular weight.

  When the catalyst is not used (no catalyst), the reaction temperature of the polyurethane polyol synthesis is preferably 100 ° C. or higher, preferably 110 ° C. or higher. In the absence of a catalyst, the reaction time of the polyurethane polyol synthesis is preferably 3 hours or more.

  The said solvent used for the said polyurethane polyol synthesis | combination is not specifically limited, For example, a well-known solvent can be used. Examples of the solvent include ketones such as methyl ethyl ketone, acetone, and methyl isobutyl ketone, esters such as ethyl acetate, n-butyl acetate, and isobutyl acetate, hydrocarbons such as toluene and xylene, and the like. In view of the solubility of the polyurethane polyol and the boiling point of the solvent, toluene is particularly preferable.

  The antioxidant is not particularly limited, and examples thereof include phenol-based and sulfur-based antioxidants.

[3. Adhesive sheet and its manufacturing method, application, etc.]
Next, the pressure-sensitive adhesive sheet of the present invention, its production method, use and the like will be described with examples.

  As described above, the pressure-sensitive adhesive sheet of the present invention is a pressure-sensitive adhesive sheet in which a pressure-sensitive adhesive layer is formed on at least one side of a substrate, and the pressure-sensitive adhesive layer is a pressure-sensitive adhesive layer formed using the pressure-sensitive adhesive of the present invention. It is characterized by that. Although the manufacturing method is not specifically limited, For example, it can manufacture with the manufacturing method (manufacturing method of the adhesive sheet by this invention) of the said this invention.

  In the production method of the present invention (manufacturing method of the pressure-sensitive adhesive sheet according to the present invention), as described above, the pressure-sensitive adhesive of the present invention is applied to the surface of the substrate on which the pressure-sensitive adhesive layer is formed. It is the manufacturing method of the adhesive sheet of the said invention including the coating process and the heating process which heats the said adhesive on the said adhesion layer formation surface after the said coating process. Hereinafter, an example will be described.

  That is, first, the pressure-sensitive adhesive of the present invention is applied to the pressure-sensitive adhesive layer-forming surface of the base material on which the pressure-sensitive adhesive layer is formed (coating step). The substrate is not particularly limited, and examples thereof include plastic, polyurethane, paper, and metal foil, but plastic is preferable. Examples of the plastic include PET (polyethylene terephthalate), PE (polyethylene), PP (polypropylene), and PC (polycarbonate).

  The shape of the substrate is not particularly limited, and examples thereof include a sheet, a film, and a foam. The base material is preferably in the form of a long tape that can be wound, for example, from the viewpoints of easy handling and storage of the pressure-sensitive adhesive sheet after manufacture.

  Moreover, the said base material may be the base material which gave the easily bonding process to the adhesive layer formation surface of the said base material as needed, for example. Although the said easy-adhesion process is not specifically limited, Specifically, the method of processing a corona discharge, the method of apply | coating an anchor coating agent, etc. are mentioned, for example.

  In addition, you may mix a solvent further prior to the said coating process for the purpose of making it easy to apply the adhesive of this invention to the said base material. The type of the solvent is not particularly limited. For example, the solvent is the same as the solvent exemplified in “2. Method for producing adhesive”, and may be used alone or in combination. Further, for example, as described above, the polyurethane polyol (A) and the crosslinking agent (B) may be mixed in the coating step or immediately before the coating step to form the pressure-sensitive adhesive of the present invention. Although the usage-amount of the said polyisocyanate is not specifically limited, For example, it is as above-mentioned.

  The coating method in the coating process is not particularly limited and may be a known method. Examples of the coating method include a roll coater method, a comma coater method, a die coater method, a reverse coater method, a silk screen method, and a gravure coater method.

  Moreover, the coating amount (coating amount) of the pressure-sensitive adhesive in the coating step is not particularly limited, but the thickness of the pressure-sensitive adhesive layer in the produced pressure-sensitive adhesive sheet is, for example, 1 to 50 μm. The thickness of the adhesive layer is preferably 5 to 30 μm, more preferably 7 to 20 μm, and still more preferably 10 to 15 μm.

  Further, after the coating step, the pressure-sensitive adhesive is heated on the pressure-sensitive adhesive layer forming surface (heating step). Hereinafter, the heating step may be referred to as a “first heating step” in order to distinguish it from a second heating step described later. Although the heating temperature in the said heating process (1st heating process) is not specifically limited, Preferably it is the temperature exceeding 90 degreeC, More preferably, it is 100 degreeC or more, More preferably, it is 130 degreeC or more. Although the upper limit of the said heating temperature is not specifically limited, For example, it is 150 degrees C or less.

  In order to prevent the pressure-sensitive adhesive layer from protruding from the edge of the base material during storage or handling of the pressure-sensitive adhesive sheet, it is preferable to increase the heating temperature in the heating step as much as possible. By increasing the heating temperature as much as possible, for example, the crosslinking (curing) reaction between the pressure-sensitive adhesive of the present invention and the cross-linking agent is likely to proceed sufficiently, so that it is estimated that the protrusion can be prevented. However, this mechanism is speculation and does not limit the present invention.

  In addition, the heating time in the heating step (first heating step) is not particularly limited. For example, the applied pressure-sensitive adhesive is sufficiently dried (solvent removal), and the base material is heated. Time that does not damage is preferred. The specific heating time is, for example, 30 to 240 seconds, preferably 60 to 180 seconds, although it depends on the type of the solvent and the substrate.

  Furthermore, in the manufacturing method of the adhesive sheet by this invention, it is preferable to include the 2nd heating process heated at the temperature lower than the said heating process after the said heating process (1st heating process). The second heating step may or may not be performed. However, by performing this, it is possible to more effectively prevent the adhesive layer from protruding from the end of the substrate. Although the phenomenon that occurs in the second heating step is unknown, for example, it is estimated that the curing (crosslinking) of the adhesive layer is further progressing. However, this assumption does not limit the present invention. The heating temperature in the second heating step is not particularly limited, but is, for example, 30 to 50 ° C, preferably 35 to 45 ° C. Moreover, the heating time in the second heating step is not particularly limited, but is, for example, 24 to 120 hr, preferably 48 to 96 hr.

  As described above, the pressure-sensitive adhesive or pressure-sensitive adhesive sheet of the present invention is excellent in stain resistance to the adherend surface. According to the pressure-sensitive adhesive or pressure-sensitive adhesive sheet of the present invention, for example, it is possible to obtain excellent stain resistance (anti-adherent stain resistance) while maintaining the low adhesive force necessary for peelability (removability). It is.

  Although the use of the adhesive sheet of this invention is not specifically limited, As above-mentioned, it is preferable to use as a protective sheet of the said image display surface by affixing on the image display surface of an image display apparatus. Moreover, when using for this use, it is more preferable that the said base material is transparent, for example.

  As described above, the image display device of the present invention is an image display device in which the protective sheet of the image display device is attached to the image display surface, and the protective sheet is the pressure-sensitive adhesive sheet of the present invention. Features. Although it does not specifically limit as said image display apparatus, For example, a mobile telephone, a smart phone, a tablet computer etc. are mentioned. However, the use of the pressure-sensitive adhesive sheet of the present invention is not limited to the image display device, and can be used, for example, as a protective sheet for window glass of automobiles and buildings. Moreover, the adhesive sheet of this invention is not limited to glass, for example, It can use also as a protective sheet for ITO (Indium Tin Oxide, indium tin oxide) processed on the glass substrate as a transparent conductive film. Furthermore, the application of the pressure-sensitive adhesive sheet of the present invention is not limited to these, and can be widely used for the same applications as, for example, a general pressure-sensitive adhesive sheet, a pressure-sensitive adhesive film, and a pressure-sensitive adhesive tape. In addition, the use of the pressure-sensitive adhesive of the present invention is not particularly limited only to the pressure-sensitive adhesive sheet of the present invention, and can be widely used for the same applications as the pressure-sensitive adhesive, for example.

  Although the form of the pressure-sensitive adhesive sheet of the present invention is not particularly limited, for example, during storage, a separator is affixed on the pressure-sensitive adhesive layer to protect the pressure-sensitive adhesive layer, and immediately before use (for example, affixing to an image display device, etc.) It is preferable to peel the separator. Moreover, for example, the pressure-sensitive adhesive sheet of the present invention is a long tape that can be wound, and is preferably wound and stored. According to the pressure-sensitive adhesive tape of the present invention, it is possible to prevent the pressure-sensitive adhesive layer from protruding from the end of the pressure-sensitive adhesive tape during winding and storage.

  Examples of the present invention will be described below. The present invention is not limited to these examples.

[Reference Examples 1 to 6]
Using each component shown in the following Tables 3 to 5, polyurethane polyol (A) -containing compositions 1 to 6 were produced (synthesized) by the method described later. As will be described later, this polyurethane polyol (A) -containing composition (hereinafter sometimes simply referred to as “composition”) is added with a crosslinking agent (B) and mixed to form the pressure-sensitive adhesive of this example.

In Tables 3 to 5 below, “glycerin PO · EO” represents a propylene oxide and ethylene oxide adduct of glycerin. “DBTDL” represents dibutyltin dilaurate. The fatty acid ester is represented by the following chemical formula (1001), n is an average of 12 (having a distribution) fatty acid ester, and the average number of carbon atoms in one molecule is 40.

[Reference Example 1]
Using the raw materials shown in the column of “Composition 1” in Table 3, Composition 1 was produced. That is, first, a polyol (trifunctional), Duranate D101 (trade name of Asahi Kasei Chemicals Corporation), toluene, and dibutyltin dilaurate (DBTDL) are placed in a separable flask and heated at 45 ° C. to 55 ° C. with stirring for 2 hours. And reacted. Two hours after the start of heating, it was cooled to 40 ° C. or lower. After cooling, an antioxidant was added and stirred until uniform to obtain Composition 1. Duranate D101 is a urethane prepolymer having two isocyanate groups represented by the chemical formula (B4). Hereinafter, the chemical formula (B4) is shown again. In Duranate D101, R ³⁰¹ and R ³⁰² in the following chemical formula (B4) are polytetramethylene ether chains —O— (CH ₂ CH ₂ CH ₂ CH ₂ O) _n −, and R ³⁰³ is a hexamethylene group — ( CH _{2) 6} -.

[Reference Example 2]
A composition 2 was produced in the same manner as in Reference Example 1, except that the raw material of “Composition 2” in the same table was used instead of the raw material of “Composition 1” in Table 3. As shown in Table 3, the raw material of “Composition 2” is “Composition” except that hexamethylene diisocyanate was used instead of duranate D101 as an isocyanate, and the contents of other components were slightly different. It is the same as the raw material of “1”.

[Reference Example 3]
A composition 3 was produced in the same manner as in Reference Example 1 except that the raw material of “Composition 3” in Table 4 was used instead of the raw material of “Composition 1” in Table 3. As shown in Table 4, the raw material of “Composition 3” was “Composition 1” except that Duranate A-201H (trade name of Asahi Kasei Chemicals Corporation) was used as the isocyanate instead of Duranate D101. The same as the raw material. Duranate A-201H is a bifunctional allophanate (having two isocyanate groups) represented by the following chemical formula (A-201H). In the following chemical formula (A-201H), R1 has 4 to 4 carbon atoms. 10 linear or branched alkyls (with intermolecular distribution).

[Reference Example 4]
A composition 3 was produced in the same manner as in Reference Example 1 except that the raw material of “Composition 4” in Table 4 was used instead of the raw material of “Composition 1” in Table 3. As shown in Table 4, “Composition 1” was used except that Desmodur N3400 (trade name of Sumika Bayer Urethane Co., Ltd.) was used as the isocyanate instead of Duranate D101. It is the same as the raw material. Desmodur N3400 is a bifunctional uretdione (having two isocyanate groups) represented by the following chemical formula (N3400).

[Reference Example 5]
A composition 5 was produced in the same manner as in Reference Example 1 except that the raw material of “Composition 5” in Table 5 was used instead of the raw material of “Composition 1” in Table 3. As shown in Table 5, the raw material of “Composition 5” includes the fatty acid ester of the chemical formula (1001) and the raw material of “Composition 1” except that the content of other components is different. It is the same. The fatty acid ester of the chemical formula (1001) was added at the same time when the antioxidant was added after heating and cooling.

[Reference Example 6]
A composition 5 was produced in the same manner as in Reference Example 2, except that the raw material of “Composition 6” in Table 5 was used instead of the raw material of “Composition 2” in Table 3. As shown in Table 5, the raw material of “Composition 6” includes the fatty acid ester of the chemical formula (1001) and the raw material of “Composition 2” except that the content of other components is different. It is the same. The fatty acid ester of the chemical formula (1001) was added at the same time when the antioxidant was added after heating and cooling.

[Examples 1-14 and Comparative Examples 1-10]
As described below, a crosslinking agent was added to each of the compositions of Reference Examples 1 to 6 (polyurethane polyol (A) -containing composition) to produce the respective adhesives of Examples 1 to 14 and Comparative Examples 1 to 10. .

[Example 1]
For 100 parts by weight of composition 1 (polyurethane polyol (A) -containing composition) of Reference Example 1, 7.7 parts by weight of Duranate D101 (polyisocyanate manufactured by Asahi Kasei Chemicals Corporation) and 50 parts by weight of ethyl acetate are blended, What was well stirred was used as the pressure-sensitive adhesive (coating liquid) of this example.

[Example 2]
6.4 parts by weight of Duranate 24A-100 (trade name of Asahi Kasei Chemicals Co., Ltd.) and 50 parts by weight of ethyl acetate are blended with 100 parts by weight of composition 1 (polyurethane polyol (A) -containing composition) of Reference Example 1. Then, the well-stirred one was used as the pressure-sensitive adhesive (coating liquid) of this example. Duranate 24A-100 is a biuret having three isocyanate groups represented by the chemical formula (B1). Hereinafter, the chemical formula (B1) is shown again. In Duranate 24A-100, R ¹⁰¹ , R ¹⁰² and R ^{103 in the following} chemical formula (B1) are each a hexamethylene group, that is, — (CH ₂ ) ₆ —.

[Example 3]
To 100 parts by weight of composition 1 (polyurethane polyol (A) -containing composition) of Reference Example 1, 6.6 parts by weight of Desmodur N3200 (trade name of Sumika Bayer Urethane Co., Ltd.) and 50 parts by weight of ethyl acetate What was mix | blended and stirred well was used as the adhesive (coating liquid) of a present Example. Desmodur N3200 is an HDI (hexamethylene diisocyanate) biuret represented by the following chemical formula (N3200) and has three isocyanate groups.

[Example 4]
6.9 parts by weight of Desmodur N3400 (polyisocyanate manufactured by Sumika Bayer Urethane Co., Ltd.) and 50 parts by weight of ethyl acetate with respect to 100 parts by weight of composition 1 (polyurethane polyol (A) -containing composition) of Reference Example 1 What was mix | blended and stirred well was used as the adhesive (coating liquid) of a present Example.

[Example 5]
For 100 parts by weight of composition 2 (polyurethane polyol (A) -containing composition) of Reference Example 2, 7.7 parts by weight of Duranate D101 (polyisocyanate manufactured by Asahi Kasei Chemicals Corporation) and 50 parts by weight of ethyl acetate are blended, What was well stirred was used as the pressure-sensitive adhesive (coating liquid) of this example.

[Example 6]
6.4 parts by weight of Duranate 24A-100 (polyisocyanate manufactured by Asahi Kasei Chemicals Corporation) and 50 parts by weight of ethyl acetate are blended with 100 parts by weight of composition 2 (composition containing polyurethane polyol (A)) of Reference Example 2. Then, the well-stirred one was used as the pressure-sensitive adhesive (coating liquid) of this example.

[Example 7]
With respect to 100 parts by weight of Composition 2 (Polyurethane polyol (A) -containing composition) of Reference Example 2, 6.6 parts by weight of Desmodur N3200 (polyisocyanate manufactured by Sumika Bayer Urethane Co., Ltd.) and 50 parts by weight of ethyl acetate What was mix | blended and stirred well was used as the adhesive (coating liquid) of a present Example.

[Example 8]
To 100 parts by weight of composition 2 (polyurethane polyol (A) -containing composition) of Reference Example 2, 6.9 parts by weight of Desmodur N3400 (polyisocyanate manufactured by Sumika Bayer Urethane Co., Ltd.) and 50 parts by weight of ethyl acetate What was mix | blended and stirred well was used as the adhesive (coating liquid) of a present Example.

[Example 9]
6.4 parts by weight of Duranate 24A-100 (polyisocyanate manufactured by Asahi Kasei Chemicals Co., Ltd.) and 50 parts by weight of ethyl acetate are blended with 100 parts by weight of composition 3 (polyurethane polyol (A) -containing composition) of Reference Example 3. Then, the well-stirred one was used as the pressure-sensitive adhesive (coating liquid) of this example.

[Example 10]
6.9 parts by weight of Desmodur N3400 (polyisocyanate manufactured by Sumika Bayer Urethane Co., Ltd.) and 50 parts by weight of ethyl acetate with respect to 100 parts by weight of composition 4 (composition containing polyurethane polyol (A)) of Reference Example 4 What was mix | blended and stirred well was used as the adhesive (coating liquid) of a present Example.

[Example 11]
Blending 5.4 parts by weight of Duranate 24A-100 (polyisocyanate manufactured by Asahi Kasei Chemicals Co., Ltd.) and 50 parts by weight of ethyl acetate with respect to 100 parts by weight of composition 3 (composition containing polyurethane polyol (A)) of Reference Example 5. Then, the well-stirred one was used as the pressure-sensitive adhesive (coating liquid) of this example.

[Example 12]
158 parts by weight of Desmodur N3400 (polyisocyanate manufactured by Sumika Bayer Urethane Co., Ltd.) and 50 parts by weight of ethyl acetate with respect to 100 parts by weight of composition 3 (composition containing polyurethane polyol (A)) of Reference Example 5 What was mix | blended and stirred well was used as the adhesive (coating liquid) of a present Example.

[Example 13]
Blending 5.4 parts by weight of Duranate 24A-100 (polyisocyanate manufactured by Asahi Kasei Chemicals Corporation) and 50 parts by weight of ethyl acetate with respect to 100 parts by weight of composition 4 (polyurethane polyol (A) -containing composition) of Reference Example 6. Then, the well-stirred one was used as the pressure-sensitive adhesive (coating liquid) of this example.

[Example 14]
158 parts by weight of Desmodur N3400 (polyisocyanate manufactured by Sumika Bayer Urethane Co., Ltd.) and 50 parts by weight of ethyl acetate with respect to 100 parts by weight of composition 4 (polyurethane polyol (A) -containing composition) of Reference Example 6 What was mix | blended and stirred well was used as the adhesive (coating liquid) of a present Example.

[Comparative Example 1]
Formulating 9.1 parts by weight of Duranate TKA-75E (trade name of Asahi Kasei Chemicals Co., Ltd.) and 50 parts by weight of ethyl acetate with respect to 100 parts by weight of composition 1 (polyurethane polyol (A) -containing composition) of Reference Example 1. Then, the well-stirred one was used as the pressure-sensitive adhesive (coating liquid) of this comparative example. Duranate TKA-75E is a polyisocyanate having three isocyanate groups and has an isocyanurate (cyclic trimer) structure.

[Comparative Example 2]
100 parts by weight of composition 1 (polyurethane polyol (A) -containing composition) of Reference Example 1 is blended with 12.1 parts by weight of Duranate P301-75E (trade name of Asahi Kasei Chemicals Corporation) and 50 parts by weight of ethyl acetate. Then, the well-stirred one was used as the pressure-sensitive adhesive (coating liquid) of this comparative example. Duranate P301-75E is an adduct-type trifunctional polyisocyanate.

[Comparative Example 3]
For 100 parts by weight of composition 1 (polyurethane polyol (A) -containing composition) of Reference Example 1, 7.6 parts by weight of Desmodur XP2580 (trade name of Sumika Bayer Urethane Co., Ltd.) and 50 parts by weight of ethyl acetate What was mix | blended and stirred well was used as the adhesive (coating liquid) of this comparative example. Desmodur XP2580 is a trifunctional polyisocyanate having an HDI (hexamethylene diisocyanate) allophanate structure.

[Comparative Example 4]
With respect to 100 parts by weight of composition 1 (polyurethane polyol (A) -containing composition) of Reference Example 1, 12.8 parts by weight of Desmodur Z4470BA (trade name of Sumika Bayer Urethane Co., Ltd.) and 50 parts by weight of ethyl acetate What was mix | blended and stirred well was used as the adhesive (coating liquid) of this comparative example. Desmodur Z4470BA is a polyisocyanate having an IPDI (isophorone diisocyanate) isocyanurate structure.

[Comparative Example 5]
12.6 parts by weight of Desmodur XP2565 (polyisocyanate manufactured by Sumika Bayer Urethane Co., Ltd.) and 50 parts by weight of ethyl acetate with respect to 100 parts by weight of the composition 1 (polyurethane polyol (A) -containing composition) of Reference Example 1 What was mix | blended and stirred well was used as the adhesive (coating liquid) of this comparative example. Desmodur XP2565 is a trifunctional polyisocyanate having an IPDI allophanate structure.

[Comparative Example 6]
9.1 parts by weight of Duranate TKA-75E (Asahi Kasei Chemicals Polyisocyanate) and 50 parts by weight of ethyl acetate are added to 100 parts by weight of composition 2 (polyurethane polyol (A) -containing composition) of Reference Example 2. Then, the well-stirred one was used as the pressure-sensitive adhesive (coating liquid) of this comparative example.

[Comparative Example 7]
100 parts by weight of composition 2 (polyurethane polyol (A) -containing composition) of Reference Example 2 is blended with 12.1 parts by weight of Duranate P301-75E (polyisocyanate manufactured by Asahi Kasei Chemicals Corporation) and 50 parts by weight of ethyl acetate. Then, the well-stirred one was used as the pressure-sensitive adhesive (coating liquid) of this comparative example.

[Comparative Example 8]
For 100 parts by weight of composition 2 (polyurethane polyol (A) -containing composition) of Reference Example 2, 7.6 parts by weight of Desmodur XP2580 (polyisocyanate manufactured by Sumika Bayer Urethane Co., Ltd.) and 50 parts by weight of ethyl acetate What was mix | blended and stirred well was used as the adhesive (coating liquid) of this comparative example.

[Comparative Example 9]
With respect to 100 parts by weight of composition 2 (polyurethane polyol (A) -containing composition) of Reference Example 2, 12.8 parts by weight of Desmodur Z4470BA (polyisocyanate manufactured by Sumika Bayer Urethane Co., Ltd.) and 50 parts by weight of ethyl acetate What was mix | blended and stirred well was used as the adhesive (coating liquid) of this comparative example.

[Comparative Example 10]
12.6 parts by weight of Desmodur XP2565 (polyisocyanate manufactured by Sumika Bayer Urethane Co., Ltd.) and 50 parts by weight of ethyl acetate with respect to 100 parts by weight of composition 2 (polyurethane polyol (A) -containing composition) of Reference Example 2 What was mix | blended and stirred well was used as the adhesive (coating liquid) of this comparative example.

[Examples 1-2 to 14-2 and Comparative Examples 1-2 to 10-2]
Using the adhesives of Examples 1 to 12 and Comparative Examples 1 to 10, the adhesive sheets (adhesive tapes) of Examples 1-2 to 14-2 and Comparative Examples 1-2 to 10-2 were used as follows. Manufactured.

[Example 1-2]
Immediately after the preparation, the pressure-sensitive adhesive (coating solution) of Example 1 was applied onto a PET film (base material) having a thickness of 38 μm or 100 μm so that the pressure-sensitive adhesive film thickness after drying was 10 to 15 μm. After leaving it in a 130 ° C. constant temperature bath for 2 minutes and heating and drying (first heating step), it is further left in a 40 ° C. constant temperature bath for 3 days to cure (crosslink) the adhesive (first cross-linking). 2), the pressure-sensitive adhesive sheet (pressure-sensitive adhesive tape) of this example was produced.

[Examples 2-2 to 14-2, Comparative Examples 1-2 to 10-2]
It replaces with the adhesive (coating liquid) of Example 1, and is the same as that of Example 1-2 except using the adhesive (coating liquid) in any of Examples 2-12 and Comparative Examples 1-10, respectively. Thus, pressure-sensitive adhesive sheets (pressure-sensitive adhesive tapes) of Examples 2-2 to 14-2 and Comparative Examples 1-2 to 10-2 were produced.

[Evaluation of adhesive strength, stain resistance (contamination resistance to adherend) and PET substrate adhesion]
About the pressure-sensitive adhesive sheets of Examples 1-2 to 12-2 and Comparative Examples 1-2 to 10-2, the adhesion strength, stain resistance (adhesion resistance), and PET substrate adhesion were measured by the following methods. evaluated.

1. Adhesive strength For the evaluation of adhesive strength, a pressure sensitive adhesive sheet produced by applying a coating liquid (adhesive) on a PET film having a thickness of 38 μm was used as a sample. Under an environment of 23 ° C. × humidity of 50%, the sample was cut to a width of 25 mm and bonded to an adherend (glass plate) with a load of 3 kg of a 2 kg roller. After this was cured for 1 hour, the peel strength (N / 25 mm) when one end of the sample was peeled off at a speed of 300 mm / min in the 180 ° direction by an autograph was defined as the adhesive strength. From the viewpoint of removability as an adhesive sheet, it is preferable that this adhesive force (peeling force) is not excessively large.

2. Contamination resistance (contamination resistance to adherend)
Contamination resistance (resistance to adherend contamination) was evaluated by a wet heat aging test. Specifically, the wet heat aging test was performed as follows. An adhesive sheet produced by applying a coating liquid (adhesive) on a PET film having a thickness of 38 μm was used as a sample. Under an environment of 23 ° C. × humidity of 50%, the sample was cut to a width of 25 mm and bonded to an adherend (glass plate) with a load of 3 kg of a 2 kg roller. After curing for 1 hour, this was left in a thermostat adjusted to a temperature of 80 ° C. and a humidity of 80% RH for 5 days. The sample after the wet heat aging test was taken out from the thermostatic bath, left at room temperature for 1 hour, and then the adhesive sheet was peeled off from the adherend. Thereafter, the adherend from which the pressure-sensitive adhesive sheet was peeled was visually checked for cloudiness. When confirming cloudiness, white light was irradiated as needed. Moreover, the evaluation criteria of stain resistance (anti-adherent stain resistance) are as follows.

A: No fogging is observed on the adherend even when irradiated with white light.
○: Slight cloudiness is observed on the adherend when irradiated with white light.
Δ: When white light is irradiated, the adherend is clouded.
X: Cloudiness is observed on the adherend without irradiation with white light.

3. PET substrate adhesion For the evaluation of PET substrate adhesion, an adhesive sheet produced by applying a coating solution on a PET film having a thickness of 100 μm was used as a sample. Using a cutter knife, the sample was cut only in the adhesive layer (cured film of the adhesive). The presence or absence of peeling of the adhesive layer (adhesive film) from the PET substrate when the cut portion was rubbed with a finger was evaluated as the PET substrate adhesion. The evaluation results were as follows: ○, Δ, or ×. In addition, if the adhesion of the adhesive layer to the base material (PET base material in this example) is high, during processing of the adhesive sheet (for example, during slit processing, punching processing), during storage, during use, The adhesive layer is difficult to peel from the substrate. Thereby, for example, during the processing, the residue due to the peeling of the adhesive layer is hardly generated.

(PET substrate adhesion evaluation results)
◎: No peeling ○: Partial peeling △: All peeling

  As shown in Tables 6 and 7, each of the pressure-sensitive adhesive sheets of Examples 1-2 to 14-2 (pressure-sensitive adhesives of Examples 1 to 14) is excellent in stain resistance (anti-adherent stain resistance). It was. Moreover, since the adhesive sheets of Examples 1-2 to 14-2 (the adhesives of Examples 1 to 14) all have low adhesive strength, they are excellent in releasability (removability). confirmed. Thus, according to the present invention, for example, it is possible to obtain excellent stain resistance (anti-adherent stain resistance) while maintaining a low adhesive force necessary for peelability (removability). . In contrast, the pressure-sensitive adhesive sheets of Comparative Examples 1-2 to 10-2 (pressure-sensitive adhesives of Comparative Examples 1 to 10) were not inferior to the examples in terms of low adhesive strength, but were performed after peeling from the adherend surface. Compared with the example, whitening of the adherend surface was conspicuous. That is, the pressure-sensitive adhesive sheets of Comparative Examples 1-2 to 10-2 were inferior in stain resistance (anti-adherent stain resistance) as compared with the pressure-sensitive adhesive sheets of Examples.

  Moreover, as shown in the said Tables 6-9, Examples 11-14 (Examples 11-2 to 14-2) which added the carboxylic acid represented by the said Chemical formula (1001) are implementation which does not add the said carboxylic acid. The substrate adhesiveness was further superior to Examples 1 to 10 (Examples 1-2 to 10-2) and Comparative Examples 1 to 10 (Comparative Examples 1-2 to 10-2). Specifically, in Examples 11 to 14 (Examples 11-2 to 14-2), even when heated at a high temperature (for example, about 130 ° C.) after applying the pressure-sensitive adhesive to the base material, the base material adhesion is good. It did not drop. Moreover, since Examples 11-14 (Examples 11-2 to 14-2) can be heated at such a high temperature, the curing (crosslinking) of the pressure-sensitive adhesive can sufficiently proceed, and the pressure-sensitive adhesive There was no problem that the agent protruded from the edge of the substrate.

  As described above, according to the present invention, a pressure-sensitive adhesive having excellent stain resistance to the adherend surface, a polyurethane prepolymer, a crosslinking agent, a pressure-sensitive adhesive manufacturing kit, a pressure-sensitive adhesive sheet, a method for manufacturing a pressure-sensitive adhesive sheet, and An image display device can be provided. The pressure-sensitive adhesive, pressure-sensitive adhesive sheet and pressure-sensitive adhesive sheet manufacturing method of the present invention are, for example, window glass for mobile phones, smartphones, automobiles, buildings, etc., or various displays, optical members such as ITO (indium tin oxide) transparent conductive film, etc. It can be used as a protective sheet. In addition, the present invention is not limited to this, and can be widely used in various applications. For example, the present invention can be widely applied to fields where general pressure-sensitive adhesives, pressure-sensitive adhesive sheets, and methods for producing pressure-sensitive adhesive sheets are used. .

Claims (14)

A pressure-sensitive adhesive containing the following components (A) and (B),

(A) Prepolymer of polyurethane (B) Crosslinking agent

The prepolymer (A) has a hydroxyl group,
The crosslinking agent (B) has an isocyanate group ,
The prepolymer (A) is a polyurethane polyol obtained by reacting a polyol having 3 or more hydroxyl groups in one molecule with a polyisocyanate, and the polyol does not contain a nitrogen atom,
And,
The said crosslinking agent (B) contains the following (B1), The adhesive characterized by the above-mentioned.

(B1) Biuret having three isocyanate groups in one molecule   The pressure-sensitive adhesive according to claim 1, wherein the prepolymer (A) is a polyurethane polyol obtained by reacting a polyol having three or more hydroxyl groups in one molecule with a polyisocyanate having two isocyanate groups in one molecule. Agent. The prepolymer (A) is a prepolymer obtained by reacting the following component (a1) with at least one selected from the group consisting of the following components (a2) to (a5). Adhesive.

(A1) Polyol having three or more hydroxyl groups in one molecule (a2) Allophanate having two isocyanate groups in one molecule (a3) Uretodione having two isocyanate groups in one molecule (a4) Isocyanate in one molecule Urethane prepolymer having two groups (a5) Biuret having two isocyanate groups in one molecule   The pressure-sensitive adhesive according to claim 3, wherein the component (a1) is triol-type polypropylene glycol (PPG).   The pressure-sensitive adhesive according to claim 3 or 4, wherein the component (a4) is a urethane prepolymer obtained by reacting a diol having an average molecular weight of 250 to 1800 with HDI (hexamethylene diisocyanate).   The pressure-sensitive adhesive according to any one of claims 1 to 5, wherein the number of isocyanate groups of the cross-linking agent (B) is 0.4 to 1.0 in terms of molar ratio with respect to the number of hydroxyl groups of the prepolymer (A). . The pressure-sensitive adhesive according to any one of claims 1 to 6, further comprising a carboxylic acid ester, wherein the carboxylic acid ester satisfies at least one of the following conditions [III] and [IV].

[III] The carboxylic acid ester contains an ether bond in the molecule.

[IV] The carboxylic acid ester contains 31 or more carbon atoms in one molecule.
The pressure-sensitive adhesive according to claim 7, wherein the carboxylic acid ester is a carboxylic acid ester represented by the following chemical formula (II).

In the chemical formula (II),
R ¹ is a hydrocarbon group or a group containing an ether bond, and the hydrocarbon group and the group containing an ether bond may be saturated or unsaturated, and may be linear, branched or cyclic, aromatic May or may not contain a ring, may or may not be substituted with further substituents, and each R ¹ may be the same or different,
R ²⁰ is a hydrocarbon group or a group containing an ether bond, and the hydrocarbon group and the group containing an ether bond may be saturated or unsaturated, and include a linear structure, a branched structure, or a cyclic structure. May or may not contain, may or may not contain an aromatic ring, may or may not be substituted with a further substituent,
At least one of R ¹ and R ²⁰ is a group containing an ether bond. R ²⁰ is a group obtained by removing hydroxyl groups at both ends in PEG (polyethylene glycol), PPG (polypropylene glycol), or EO / PO glycol (glycol which is a copolymer of ethylene oxide (EO) and propylene oxide (PO)). The pressure-sensitive adhesive according to claim 8. The pressure-sensitive adhesive according to claim 8 or 9, wherein R ¹ is a linear or branched alkyl group or an aralkyl group.   The linear or branched alkyl group is a linear or branched alkyl group having 2 to 5 carbon atoms, and in the aralkyl group, the alkyl group portion is a linear or branched alkyl group having 2 to 5 carbon atoms. The pressure-sensitive adhesive according to claim 10. The pressure-sensitive adhesive according to claim 8, wherein the carboxylic acid ester represented by the chemical formula (II) is at least one of a carboxylic acid ester represented by the following chemical formula (1001) and a carboxylic acid ester represented by the following chemical formula (1010). Agent.

An adhesive sheet having an adhesive layer formed on at least one side of a substrate,
The pressure-sensitive adhesive sheet, wherein the pressure-sensitive adhesive layer is a pressure-sensitive adhesive layer formed using the pressure-sensitive adhesive according to any one of claims 1 to 12. An image display device in which a protective sheet of the image display device is attached to an image display surface,
The image display device, wherein the protective sheet is the pressure-sensitive adhesive sheet according to claim 13.