KR20200052213A - Adhesive composition, adhesive sheet, manufacturing method for adhesive sheet and image display device - Google Patents

Abstract

Provided is an adhesive capable of satisfying re-peelability, wettability, and adherend contamination resistance under high temperature and high humidity. The adhesive of the present invention comprises: a urethane prepolymer (A) having a hydroxyl group; and nonionic sulfonic acid ester (B).

Description

A pressure-sensitive adhesive, a pressure-sensitive adhesive sheet, a manufacturing method of the pressure-sensitive adhesive sheet, and an image display device {ADHESIVE COMPOSITION, ADHESIVE SHEET, MANUFACTURING METHOD FOR ADHESIVE SHEET AND IMAGE DISPLAY DEVICE}

The present invention relates to an adhesive, an adhesive sheet, a method of manufacturing the adhesive sheet, and an image display device.

The pressure-sensitive adhesive and the pressure-sensitive adhesive sheet using the same are widely used in various fields in industry. As a specific use, for example, a protective film or the like that is attached to a surface of glass or the like is used. As said glass, windowpanes, such as a mobile phone, a smart phone, a car, a building, are mentioned, for example.

Examples of the pressure sensitive adhesive include an acrylic resin pressure sensitive adhesive, a rubber pressure sensitive adhesive, and a urethane pressure sensitive adhesive. Among these, the urethane adhesive has properties such as a property that can be peeled off after being attached (hereinafter referred to as re-peelability), or a property in which bubbles or the like are difficult to pull into the interface between the adhesive layer and the adherend (hereinafter referred to as wettability). Because it is excellent in, it is widely used (Patent Document 1, etc.).

Patent Document 1: Japanese Patent Publication No. 2016-186064

In recent years, adhesives used for adhesive sheets for surface protection, etc., in addition to removability and wettability, require adherend contamination. This is because a product with an adhesive attached to a surface such as plastic or glass may be transported or stored over a long period of time. Here, the adherend stain resistance means that, even when the product with the adhesive sheet is placed under high temperature and high humidity conditions for a long time, when the adhesive sheet is peeled, contamination from the adhesive to the adherend does not occur. In addition, since the degree of contamination differs depending on the type of the material (adherent) to which the pressure-sensitive adhesive is applied and the environment where the product is left for a long time, the required contamination resistance of the adherend is also different. In addition, what is considered as the cause of the contamination includes deterioration contamination derived from the material of the adherend, in addition to traces of the glue originating from the pressure-sensitive adhesive.

Accordingly, an object of the present invention is to provide a pressure-sensitive adhesive, a pressure-sensitive adhesive sheet, a method for manufacturing the pressure-sensitive adhesive sheet, and an image display device capable of satisfying re-peelability, wettability, and adherend contamination under high temperature and high humidity.

To achieve the above object, the pressure-sensitive adhesive of the present invention is characterized in that it comprises a urethane prepolymer (A) having a hydroxyl group and a nonionic sulfonic acid ester (B).

The adhesive sheet of the present invention is an adhesive sheet in which an adhesive layer is formed on at least one surface of a base material, and the adhesive layer is characterized in that it is an adhesive layer formed of the adhesive of the present invention.

The manufacturing method of the pressure-sensitive adhesive sheet of the present invention includes the coating step of coating the pressure-sensitive adhesive of the present invention on the pressure-sensitive adhesive layer formation surface on which the pressure-sensitive adhesive layer is formed, and after the coating step, the pressure-sensitive adhesive layer is formed. It is a method of manufacturing the pressure-sensitive adhesive sheet of the present invention comprising a heating step of heating the pressure-sensitive adhesive on the surface.

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

According to the present invention, it is possible to provide an adhesive, a pressure-sensitive adhesive sheet, a method of manufacturing the pressure-sensitive adhesive sheet, and an image display device capable of satisfying re-peelability, wettability, and adherend contamination under high temperature and high humidity.

Hereinafter, the present invention will be described by way of example. However, the present invention is not limited by the following description.

For the pressure-sensitive adhesive of the present invention, for example, the urethane prepolymer (A) may be an adduct of polyol and isocyanate.

The pressure-sensitive adhesive of the present invention may further contain, for example, a crosslinking agent (C), and the crosslinking agent (C) may be polyisocyanate.

The adhesive of the present invention may be, for example, an adhesive for forming an adhesive sheet by forming an adhesive layer on at least one surface of the substrate. In addition, in the pressure-sensitive adhesive sheet of the present invention, the base material may be, for example, a polyethylene terephthalate or polyolefin.

In the present invention, the "aliphatic group" is not particularly limited, and for example, it may be saturated or unsaturated, or may be included even if it does not contain a cyclic structure. As said aliphatic group, an alkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group, a cycloalkenyl group etc. are mentioned, for example.

In the present invention, "alkyl" includes, for example, straight-chain or branched alkyl. The number of carbon atoms of the alkyl is not particularly limited, and is, for example, 1 to 30, and preferably 1 to 18, 3 to 16, or 4 to 12. The alkyl is not particularly limited, for example, 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, etc. Can be heard. The same applies to groups derived from alkyl groups and atomic groups (such as alkoxy groups). The same applies to groups containing an alkyl group in the structure (alkylamino group, alkoxy group, etc.), or groups derived from alkyl groups (haloalkyl groups, hydroxyalkyl groups, aminoalkyl groups, alkanol groups, etc.).

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

In the present invention, "aromatic ring" or "aromatic group" includes, for example, aryl, heteroaryl and arylalkyl. In addition, the "cyclic structure" includes, for example, the aforementioned aromatic rings, cycloalkyls, bridged cyclic hydrocarbon groups, spirohydrocarbon groups, and cycloalkenyls.

In the present invention, "aryl" includes, for example, a monocyclic aromatic hydrocarbon group and a polycyclic aromatic hydrocarbon group. As said monocyclic aromatic hydrocarbon group, phenyl etc. are mentioned, for example. The polycyclic aromatic hydrocarbon group is, for example, 1-naphthyl, 2-naphthyl, 1-anthryl, 2-anthryl, 9-anthryl, 1-phenanthryl, 2-phenanthryl, 3-phenanthryl, 4-phenanthryl, 9-phenanthryl, and the like. Preferably, naphthyl etc., such as phenyl, 1-naphthyl and 2-naphthyl, are mentioned, for example.

In the present invention, "heteroaryl" includes, for example, a monocyclic aromatic heterocyclic group and a condensed aromatic heterocyclic group. The heteroaryl is, for example, furyl (eg 2-furyl), thienyl (eg 2-thienyl), pyrrolyl (eg 1-pyrrolyl), imidazolyl (eg 1-imida Zolyl), pyrazolyl (eg 1-pyrazolyl), triazolyl (eg 1,2,4-triazol-1-yl), tetrazolyl (eg 1-tetrazolyl), oxazolyl (eg 2 -Oxazolyl), isoxazolyl (eg 3-isoxazolyl), thiazolyl (eg 2-thiazolyl), thiadiazolyl, isothiazolyl (eg 3-isothiazolyl), pyridyl (eg : 2-pyridyl), pyridazinyl (eg 3-pyridazinyl), pyrimidinyl (eg 2-pyrimidinyl), furazanyl (eg 3-furazinyl), pyrazinyl (eg 2 -Pyrazinyl), oxadiazolyl (eg 1,3,4-oxadiazol-2-yl), benzofuryl (eg 2-benzo [b] furyl), benzothienyl (eg 2-benzo [ b] thienyl), benzimidazolyl (e.g. 1-benzoimidazolyl), dibenzofuryl, benzooxazolyl, benzothiazolyl, quinoxalyl (e.g. 2-quinolsarinyl), cynolinyl (e.g. : 3-cinnolinyl), quinazole (Eg 2-quinazolinyl), quinolyl (eg 2-quinolyl), phthalazinyl (eg 1-phthalazinyl), isoquinolyl (eg 1-isoquinolyl), furyl, fruyl Teridinyl (e.g. 2-pteridinyl), carbazolyl, phenanthridinyl, acridinyl (e.g. 1-acridinyl), indolyl (e.g. 1-indolyl), isoindolyl, phenazineyl (Example: 1-phenazinyl) or Phenothiazineyl (eg 1-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 to 24 or 3 to 15. Examples of the cycloalkyl include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, bridged cyclic hydrocarbon groups, spirohydrocarbon groups, and the like, preferably cyclopropyl, cyclo And butyl, cyclopentyl, cyclohexyl, and bridged cyclic hydrocarbon groups.

In the present invention, the "bridged cyclic hydrocarbon group" is, 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, the "spirohydrocarbon group" includes, for example, spiro [3.4] octyl.

In the present invention, "cycloalkenyl" contains, for example, a cyclic unsaturated aliphatic hydrocarbon group, and has 3 to 24 or 3 to 7 carbon atoms, for example. Examples of the cyclic unsaturated aliphatic hydrocarbon group include cyclopropenyl, cyclobutenyl, cyclopentenyl, clohexenyl, cycloheptenyl, and the like, preferably cyclopropenyl, cyclobutenyl, cyclo Pentenyl, cyclohexenyl, and the like. The cycloalkenyl includes, for example, a bridged cyclic hydrocarbon group having an unsaturated bond in the ring and a spirohydrocarbon group.

In the present invention, "arylalkyl" includes, for example, benzyl, 2-phenethyl, naphthalenylmethyl, and the like, and "cycloalkylalkyl" includes, for example, cyclohexylmethyl and adamantylmethyl. And the like, and examples of "hydroxyalkyl" include hydroxymethyl and 2-hydroxyethyl.

Further, in the present invention, the "substituent" or "one more substitution method" is not particularly limited, for example, carboxy, halogen, alkyl halide (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 (eg cyclohexylmethyl, adamantylmethyl), cycloalkenyl (eg cyclopropenyl), aryl (eg phenyl, naphthyl), arylalkyl (eg benzyl, phen Netyl), heteroaryl (e.g. pyridyl, furyl), heteroarylalkyl (e.g. pyridylmethyl), heterocyclyl (e.g. piperidyl), heterocyclylalkyl (e.g. morpholinylmethyl), alkoxy ( Examples: methoxy, ethoxy, propoxy, butoxy), perfluoroalkyl (e.g. CF ₃ ), halogenated alkoxy (e.g. OCF ₃ ), acyl, alkenyloxy (e.g. vinyloxy, allyloxy), Ryloxy (eg phenyloxy), alkyloxycarbonyl (eg methoxycarbonyl, ethoxycarbonyl, tert-butoxycarbonyl), arylalkyloxy (eg benzyloxy), amino [alkylamino (eg : Methylamino, ethylamino, dimethylamino), acylamino (e.g. acetylamino, benzoylamino), arylalkylamino (e.g. benzylamino, tritylamino), hydroxyamino), alkylaminoalkyl (e.g. diethyl Aminomethyl), 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. There are, for example, "alkoxyalkyl", for example, methoxymethyl, and the like, "aminoalkyl", for example, 2-aminoethyl and the like.

In the present invention, "acyl" is not particularly limited, for example, formyl, acetyl, propionyl, isobutylyl, valeryl, isovaleryl, pivaloyl, hexanoyl, cyclohexanoyl, benzoyl, Ethoxycarbonyl, and the like. The same applies to groups containing acyl groups in the structure (acyloxy groups, alkanoloxy groups, etc.). In the present invention, the carbon number of the acyl group includes carbonyl carbon, and, for example, an alkanol group (acyl group) having 1 carbon atom 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 straight-chain or branched alkyl group having 1 to 30 carbon atoms. The "perfluoroalkyl" is more specifically, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl and tert-butyl, pentyl, hexyl, heptyl, And perfluoroalkyl groups derived from groups such as octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, and icosyl. The same applies to groups containing perfluoroalkyl groups in the structure (perfluoroalkylsulfonyl groups, perfluoroacyl groups, etc.).

In addition, in the present invention, when the various groups described above are heterocycles or include heterocycles, "carbon number" also includes the number of heteroatoms constituting the heterocycle.

In addition, in the present invention, when there is an isomer such as a substituent, any isomer may be used as long as there is no clue. For example, in the case of "naphthyl group", 1-naphthyl group or 2-naphthyl group may be used, and in the case of "propyl group", n-propyl group or isopropyl group may be used.

In addition, the pressure-sensitive adhesive sheet of the present invention is characterized in that the pressure-sensitive adhesive layer is a pressure-sensitive adhesive layer formed of the pressure-sensitive adhesive of the present invention, as described above, the pressure-sensitive adhesive sheet is formed on at least one side of the substrate. It is preferable that the adhesive sheet of this invention is an adhesive sheet used as a protective sheet of the said image display surface by attaching to the image display surface of an image display apparatus.

The manufacturing method of the pressure-sensitive adhesive sheet according to the present invention is, as described above, the coating step of applying the pressure-sensitive adhesive of the present invention to the pressure-sensitive adhesive layer forming surface of the substrate, the pressure-sensitive adhesive layer is formed, and after the coating step, the pressure-sensitive adhesive It is a method of manufacturing the pressure-sensitive adhesive sheet of the present invention, comprising a heating step of heating the pressure-sensitive adhesive on the layer forming surface. In the said coating process, when the adhesive of this invention does not contain a crosslinking agent (C), it is preferable to coat the adhesive of this invention with a crosslinking agent (C).

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

[1.Adhesive]

As described above, the pressure-sensitive adhesive of the present invention includes a urethane prepolymer (A) having a hydroxyl group (hereinafter sometimes referred to as "component (A)") and a nonionic sulfonic acid ester (B) (hereinafter referred to as "component (B ) ”.

[1-1. Urethane prepolymer having hydroxyl group (A)]

The urethane prepolymer (A) is a urethane prepolymer having a hydroxyl group, as described above.

The urethane prepolymer (A) may be, for example, a polyurethane polyol synthesized from polyol and polyisocyanate. In addition, in the present invention, "urethane prepolymer" refers to a prepolymer of polyurethane. In the present invention, "polyurethane polyol" refers to a prepolymer of polyurethane and having a plurality of hydroxyl groups. In addition, in the present invention, "prepolymer" is a polymer in which polymerization or crosslinking has progressed halfway, and refers to a polymer capable of further polymerization or crosslinking. In the present invention, "prepolymer of polyurethane" refers to a polyurethane in which polymerization or crosslinking has progressed halfway, and further refers to polyurethane that can be converted into polyurethane undergoing polymerization or crosslinking. The said "prepolymer of polyurethane" can be converted into polyurethane which further polymerized or bridge | crosslinked by having multiple hydroxyl groups or isocyanate groups, for example. In the present invention, "polyurethane polyisocyanate" is a polyurethane that can be converted into a further polymerized or crosslinked polyurethane by having a plurality of isocyanate groups (e.g., at the sock end of a molecule) unless otherwise indicated. Refers to a prepolymer. However, in the present invention, the urethane prepolymer (A) is a urethane prepolymer having a hydroxyl group, as described above. In the present invention, "polyol" refers to an organic compound having a hydroxyl group (preferably at least one of an alcoholic hydroxyl group and a phenolic hydroxyl group) in one molecule, "polyisocyanate" Refers to an organic compound (polyfunctional isocyanate) having a plurality (2 or 3 or more) of isocyanato groups (-N = C = O, also referred to as isocyanate groups) in one molecule.

The hydroxyl value of the urethane prepolymer (A) is not particularly limited, but may be, for example, 1 mgKOH / g or more or 10 mgKOH / g or more, for example, 50 mgKOH / g or less, 30 mgKOH / It may be g or less or 25 mgKOH / g or less. The hydroxyl value of the urethane prepolymer (A) may be, for example, 1 to 50 mgKOH / g, 1 to 30 mgKOH / g, 10 to 30 mgKOH / g, or 10 to 25 mgKOH / g. When the hydroxyl value of the urethane prepolymer (A) is within the above-mentioned predetermined range, for example, in an adhesive sheet, an adhesive layer having a good crosslinking density is easily obtained, and wettability is further improved.

The method for measuring the hydroxyl value of the urethane prepolymer (A) is not particularly limited, but can be measured, for example, by the following method.

[Measurement method of hydroxyl value]

The hydroxyl value (OHV) of the resin can be measured by a measurement method based on JIS K1557-1: 2007. Specifically, 1 g of the resin (e.g., urethane prepolymer (A)) to be measured is acetylated with acetic acid-free acetic acid, and the number of mg of potassium hydroxide required for neutralization is the hydroxyl value of the resin [mg] KOH / g].

The urethane prepolymer (A) may be, for example, an adduct of polyol and isocyanate, as described above. The isocyanate may be, for example, polyisocyanate. The urethane prepolymer (A) can be produced, for example, by reacting the polyol with the isocyanate. In addition, adjustment of the hydroxyl value of the urethane prepolymer (A) is, for example, a method of adjusting the molecular weight of the polyol during the reaction, a method of adjusting the number of functional groups of the hydroxyl group of the polyol, the polyol and the isocyanate It can be performed by a well-known method, such as a method of adjusting the compounding ratio of. In addition, the types of the polyol and the isocyanate are described together with an example of the method for producing the pressure-sensitive adhesive of the present invention in the "2. Method for producing the pressure-sensitive adhesive" described later.

The number of functional groups of the hydroxyl group in one molecule of the polyol, which is a raw material for the urethane prepolymer (A), is not particularly limited, but is, for example, 2 to 4, particularly preferably 3. The molecular weight (number average molecular weight) of the polyol is not particularly limited, but may be, for example, 1000 to 15000, 1000 to 6000, or 2000 to 5000. It is preferable that the said polyol contains polyether polyol. For example, it is preferable that the polyol contains a trifunctional (including three hydroxyl groups in one molecule) polyether polyol, and the hydroxyl value is 10 to 170 mgKOH / g. In addition, the hydroxyl value of the polyol can be measured by the same method as that of the urethane prepolymer. Thereby, for example, a pressure-sensitive adhesive layer having a suitable crosslinking density is easy to obtain, and the pressure-sensitive adhesive sheet, which has good wettability due to low adhesive strength and does not excessively rise even when the pressure-sensitive adhesive sheet is heated, can be peeled from the adherend. At this time, it is possible to obtain effects such as the ability to suppress the residual of the adhesive layer on the adherend. Moreover, the said polyol may contain polyester polyol etc. in addition to polyether polyol, for example.

The NCO / OH ratio between the polyol as the raw material of the urethane prepolymer (A) and the isocyanate is not particularly limited, but may be, for example, 0.4 or more or 0.5 or more, for example, 0.9 or less, 0.7 or less, or 0.6 or less It's okay. The NCO / OH ratio may be, for example, in the range of 0.4 to 0.9, 0.4 to 0.7, 0.4 to 0.6, 0.5 to 0.9, 0.5 to 0.7, or 0.5 to 0.6. The NCO / OH ratio is a value obtained by dividing the number of moles of the isocyanate group in the total amount of the polyol and the isocyanate by the number of moles of the hydroxyl group.

The content of the urethane prepolymer (A) in the total mass of the pressure-sensitive adhesive of the present invention is not particularly limited, but may be, for example, 20 to 80% by mass, 30 to 70% by mass, or 40 to 60% by mass.

[1-2. Nonionic sulfonic acid ester (B)]

The nonionic sulfonic acid ester (B) is not particularly limited, and may be, for example, an aromatic sulfonic acid ester or a non-aromatic sulfonic acid ester. The non-aromatic sulfonic acid ester may be, for example, an aliphatic sulfonic acid ester. In addition, a single type of nonionic sulfonic acid ester (B) may be used, or a plurality of types may be used in combination.

In addition, in this invention, "nonionic" means that it does not ionize under normal use conditions of an adhesive even if it does not have an ionic functional group or has it, for example. As said ionic functional group, a carboxy group, a phenolic hydroxyl group, etc. are mentioned, for example.

The nonionic sulfonic acid ester (B) may be, for example, a sulfonic acid ester represented by the following formula (I).

[Formula I]

In the formula (I), R ¹ is an aliphatic group or an aromatic group. In R ¹ , the aliphatic group is not particularly limited, but is, for example, as described above, for example, an alkyl group or an alkenyl group, for example, a straight-chain or branched alkyl group having 1 to 18 carbon atoms, or 1 to 18 carbon atoms. It is a straight-chain or branched alkenyl group. In R ¹ , the aromatic group is not particularly limited, but is, for example, as described above, for example, an aryl group, and for example, a phenyl group. In addition, the aromatic group may have, for example, one or more substituents, but may not have them, and the plurality of substituents may be the same or different.

In the formula (I), R ² is an aliphatic group or an aromatic group. In R ² , the aliphatic group is not particularly limited, but is, for example, as described above, for example, an alkyl group or an alkenyl group, for example, a straight-chain or branched alkyl group having 1 to 18 carbon atoms, or 1 to 18 carbon atoms. It is a straight-chain or branched alkenyl group. In R ² , the aromatic group is not particularly limited, but is, for example, as described above, for example, an aryl group, and for example, a phenyl group. In R ² , the aliphatic group or the aromatic group may or may not have additional substituents. One or more of the additional substituents may be used, or in the case of a plurality of additional substituents, they may be the same or different. May be the same rep and - it said further substituent is not particularly limited, for example, may be a substituent described above, or, R ¹ -SO ₃ in the formula (I).

The sulfonic acid ester represented by the formula (I) may be, for example, a sulfonic acid ester represented by the following formula (II).

[Formula Ⅱ]

In the formula (II), Ar is an aromatic group. The aromatic group is not particularly limited, but is, for example, as described above, and is, for example, an aryl group. In addition, the aromatic group may have, for example, one or more substituents, but may not have them, and the plurality of substituents may be the same or different.

In the formula (II), R ² is the same as the formula (I).

The sulfonic acid ester represented by the above formula (I) may be, for example, a sulfonic acid ester represented by the following formula (III).

[Formula Ⅲ]

In the formula (III), R ² is the same as the formula (I).

In the formula (III), R ³ is a substituent, and may or may not be present, and may be 1 or 2, or may be the same or different when present.

As specific examples of the nonionic sulfonic acid ester (B), for example, p-toluenesulfonate methyl, p-toluenesulfonate ethyl, p-toluenesulfonic acid n-octyl, p-toluenesulfonic acid phenyl, ethyl methanesulfonate, 1,3- And bis (tosyloxy) propane.

The content rate of the nonionic sulfonic acid ester (B) is not particularly limited, but is, for example, 0.1 mass% or more, 0.3 mass% or more, 0.5 mass% or more, or 1 mass% with respect to the total mass of the urethane prepolymer (A). The above may be used, for example, 25% by mass or less, 13% by mass or less, 8% by mass or less, or 5% by mass or less. In addition, the above-mentioned "total mass of urethane prepolymer (A)" is only the urethane prepolymer (A) except impurities (for example, a solvent when using the urethane prepolymer (A) in the form of a solution, emulsion, etc.). Say mass. From the viewpoint of adherend contamination, it is preferable that the nonionic sulfonic acid ester (B) is not too small. In addition, from the viewpoint of suppressing the phenomenon that the hydrolysis product of the nonionic sulfonic acid ester (B) deteriorates product stability or inhibits a crosslinking reaction when processed into an adhesive sheet, the nonionic sulfonic acid ester (B) is too large. It is preferred.

[1-3.Crosslinking system (C)]

As described above, the pressure-sensitive adhesive of the present invention further contains a crosslinking agent (C), and the crosslinking agent (C) may be a polyisocyanate. In addition, in the present invention, "polyisocyanate", as described above, in one molecule, an organic group having a plurality of isocyanate groups (also referred to as isocyanato groups), that is, (-N = C = O) (2 or 3 or more) Refers to a compound (polyfunctional isocyanate).

When the pressure-sensitive adhesive of the present invention contains the polyisocyanate as the crosslinking agent (C), the content is not particularly limited, but, for example, the isocyanate of the polyisocyanate with respect to the molar amount of hydroxyl groups of the polyurethane polyol The group may have a molar amount of 0.5 to 5 times or 1 to 4 times.

In the crosslinking agent (C), the polyisocyanate is not particularly limited. The polyisocyanate may be, for example, the same as the polyisocyanate used for the synthesis of the urethane prepolymer (A), which is exemplified in "2. Adhesive Manufacturing Method" described later, and may also be, for example, trimethylolpropane. A duct body, a burette body reacting with water, a trimer having an isocyanurate ring, or the like may be used, or a single type may be used in combination.

[1-4: other ingredients]

The pressure-sensitive adhesive of the present invention includes the components (A) and (B) as described above. The component (C) (crosslinking agent (C)) may or may not be included as described above. In addition, the pressure-sensitive adhesive of the present invention may or may not contain other components than the components (A) to (C). For example, the pressure-sensitive adhesive of the present invention may further contain a solvent, a plasticizer, an antioxidant, a crosslinking agent, a filler, a colorant, an ultraviolet absorber, an antifoaming agent, a light stabilizer, a leveling agent, an antistatic agent, etc. as the other components. , You do not need to include. Although the kind etc. are not specifically limited, For example, it may be the same as or similar to a general adhesive.

The antistatic agent is not particularly limited, but may be, for example, an ionic compound. It is preferable that the said ionic compound is other than an ionic compound which can show alkalinity, and an ionic sulfonic acid ester compound. Examples of the ionic compound include, for example, chloride, perchlorate, acetate, nitrate, and more specifically lithium chloride, lithium perchlorate, sodium perchlorate, potassium acetate, lithium trifluoroacetate, lithium nitrate, and the like. Can be lifted.

As said plasticizer, carboxylic acid ester etc. are mentioned, for example. Although it does not specifically limit as said carboxylic acid ester, For example, you may use the carboxylic acid esters described in Unexamined-Japanese-Patent No. 2011-190420, Unexamined-Japanese-Patent No. 2015-151429, and Unexamined-Japanese-Patent No. 2016-186029. The carboxylic acid ester may be, for example, a carboxylic acid ester in Examples described later. Although the content rate of the said plasticizer is not specifically limited, For 1 mass% or more, 3 mass% or more, 5 mass% or more, or 10 mass% or more with respect to the whole mass of urethane prepolymer (A), for example For example, it may be 150 mass% or less, 100 mass% or less, 75 mass% or less, or 60 mass% or less. As described above, "the total mass of the urethane prepolymer (A)" is a urethane prepolymer (A) excluding impurities (for example, solvent when urethane prepolymer (A) is used in the form of a solution, emulsion, etc.). ) Is the total mass of only. From the viewpoint of improving the adhesion of the pressure-sensitive adhesive to the base material (for example, a PET film) of the pressure-sensitive adhesive sheet, it is preferable that there are many plasticizers. On the other hand, it is preferable that there are not too many plasticizers from the viewpoint of suppressing the phenomenon that the adhesive strength greatly increases when the pressure-sensitive adhesive sheet is peeled from the adherend and the pressure-sensitive adhesive remains on the adherend.

Although it does not specifically limit as said ultraviolet absorber, For example, ultraviolet absorbers, such as a benzophenone type, a benzotriazole type, and a triazine type, are mentioned. Although it does not specifically limit as said antifoaming agent, For example, antifoaming agents, such as silicone type and mineral oil type, are mentioned. Although it does not specifically limit as said light stabilizer, For example, the light stabilizer, such as a hindered amine system, is mentioned. Examples of the antistatic agent include ionic compounds such as inorganic salts and organic salts, and nonionic compounds such as nonionic surfactants. The solvent, the antioxidant, and the crosslinking inhibitor are not particularly limited, but are described, for example, in the "2. Adhesive Manufacturing Method" described later, together with an example of the manufacturing method of the adhesive of the present invention. .

Moreover, although the adhesive of this invention does not need to contain even if it contains an acidic component, it is preferable that the content rate of an acidic component is as small as possible. If the content of the acidic component in the pressure-sensitive adhesive is not too high, for example, the viscosity of the pressure-sensitive adhesive increases over time, and when the pressure-sensitive adhesive is coated on a substrate (for example, a PET film, etc.), the pressure-sensitive adhesive inhibits the crosslinking reaction of the pressure-sensitive adhesive. When it comes into contact with a metal part such as a coating machine, problems such as corrosion of the metal can be suppressed. Since the nonionic sulfonic acid ester (B) has a slow hydrolysis rate and hardly generates an acidic component, the pressure-sensitive adhesive of the present invention is unlikely to cause such problems.

[2. Method of manufacturing adhesive]

The manufacturing method of the pressure-sensitive adhesive of the present invention is not particularly limited except that the components (A) and (B) are used. For example, a method of manufacturing a general pressure-sensitive adhesive may be referred to, for example, the patent You may refer to Document 1 and the like. Hereinafter, mainly, the manufacturing method in the case where the urethane prepolymer (A) is a polyurethane polyol synthesized from polyol and polyisocyanate is described, for example.

First, a polyol, a polyisocyanate, a solvent, and a catalyst are added as needed to the reaction vessel, and the reaction is performed while heating and stirring. The use amount of the polyol is not particularly limited, but is, for example, 20 to 80% by mass or 40 to 60% by mass relative to the mass of the pressure-sensitive adhesive after production. The amount of the polyisocyanate used is not particularly limited, but is, for example, 0.5 to 10% by mass or 1 to 5% by mass relative to the mass of the pressure-sensitive adhesive after production. Although the usage-amount of the said solvent is not specifically limited, For example, it is 10-50 mass% or 20-40 mass% with respect to the mass of the adhesive after manufacture. Although it is not necessary to use the said catalyst, it is preferable to use it from a viewpoint of smooth progress of a reaction. When using the catalyst, the amount of use is not particularly limited, but is, for example, 0.001 to 0.1% by mass relative to the mass of the pressure-sensitive adhesive after production. Although the reaction temperature of the said reaction is not specifically limited, For example, it is 30-80 degreeC, or 40-60 degreeC. Although the reaction time of the said reaction is not specifically limited, For example, it is 0.5 to 15 hr, 0.5 to 4 hr, or 1 to 3 hr. In this way, a composition containing a polyurethane polyol (urethane prepolymer (A)) can be synthesized.

In addition, in the synthesis of the polyurethane polyol-containing composition, for example, (1) a polyester polyol, a polyether polyol, a method of putting a catalyst, a polyisocyanate into a flask, and (2) a polyester polyol, a polyether polyol , It is possible to add a catalyst by dropping polyisocyanate into a flask and adding it. The side of (1) is convenient, but the side of (2) is easy to control the reaction, so it is possible to scrub it as needed.

In addition, component (B) is added to the synthesized polyurethane polyol-containing composition and stirred until uniform. At this time, if necessary, component (C) (crosslinking agent (C)) may be added. Moreover, you may add components other than components (A)-(C) as needed. The said other component may contain the solvent, for example, and may also contain antioxidant, crosslinking agent, carboxylic acid ester, etc. as mentioned above. In this way, the pressure-sensitive adhesive of the present invention can be obtained.

In the crosslinking agent (C), the polyisocyanate is not particularly limited, but may be the same as the polyisocyanate used for the synthesis of the polyurethane polyol (urethane prepolymer (A))-containing composition illustrated below. , A trimethylolpropane adduct, a burette that reacts with water, a trimer having an isocyanurate ring, or the like, or a combination of a plurality of types. In the crosslinking agent (C), the amount of the polyisocyanate used is not particularly limited, for example, 0.5 to 5 times or 1 to 4 times the isocyanate group of the polyisocyanate relative to the molar amount of hydroxyl groups of the urethane prepolymer (A). The molar amount of the hydroxyl group of the polyol is preferably 0.5 to 5 times or 1 to 4 times based on the molar amount or the molar amount of the isocyanate group of the polyurethane polyisocyanate.

Although it is not necessary to use the said solvent, it is preferable to use it from a viewpoint of smooth mixing of each component which comprises the adhesive of this invention. When the catalyst is used, the amount of use is not particularly limited, but is, for example, 0.001 to 0.1% by mass or 0.01 to 0.05% by mass relative to the mass of the pressure-sensitive adhesive after production. Although it is not necessary to use the said antioxidant, it is preferable to use. When using the said antioxidant, although the usage amount is not specifically limited, For example, it is 0.05-1 mass% or 0.1-0.6 mass% with respect to the mass of the adhesive after manufacture. When the said fatty acid ester is used, its use amount is not particularly limited, but is, for example, 5 to 50% by mass or 10 to 30% by mass relative to the mass of the pressure-sensitive adhesive after production.

Hereinafter, the synthesis of the polyurethane polyol (urethane prepolymer (A))-containing composition will be described in more detail.

The polyol as a raw material of the urethane prepolymer (A) is not particularly limited, and may be, for example, bifunctional (having two hydroxyl groups in one molecule) or trifunctional (having three or more hydroxyl groups in one molecule). , It is preferably trifunctional or higher, and particularly preferably trifunctional. Further, the polyol may be used alone or in combination of two or more. The polyol is not particularly limited, and may be, for example, one or both of polyester polyol and polyether polyol.

It does not specifically limit as said polyester polyol, For example, well-known polyester polyol may be sufficient. As an acid component of the said polyester polyol, terephthalic acid, adipic acid, azelaic acid, sebacic acid, phthalic anhydride, isophthalic acid, trimellitic acid etc. are mentioned, for example. As the glycol component of the polyester polyol, for example, ethylene glycol, propylene glycol, diethylene glycol, butylene glycol, 1,6-hexane glycol, 3-methyl-1 5-pentanediol, 3,3'-dimethyl All-heptane, polyoxyethylene glycol, polyoxypropylene glycol, 1,4-butanediol, neopentyl glycol, butylethylpentanediol, and the like. As a polyol component of the said polyester polyol, glycerin, trimethylolpropane, pentaerythritol, etc. are mentioned, for example. In addition, polyester polyols obtained by ring-opening polymerization of lactones such as polycaprolactone, poly (β-methyl-γ-valerolactone), and polyvalerolactone are also exemplified.

The molecular weight of the polyester polyol is not particularly limited, and can be used from low molecular weight to high molecular weight. Preferably, a polyester polyol having a number average molecular weight of 500 to 5,000 is used. When the number average molecular weight is 500 or more, the reactivity is too high and it is easy to prevent gelation. Moreover, when the number average molecular weight is 5,000 or less, it is easy to prevent a decrease in reactivity and a decrease in cohesive force of the polyurethane polyol itself. The polyester polyol may or may not be used, but the amount used may be, for example, 10 to 90 mol% or 10 to 50 mol% of the polyols 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, water, or low molecular weight polyols such as propylene glycol, ethylene glycol, glycerin, and trimethylol propane as an initiator, and ethylene oxide, A polyether polyol obtained by polymerizing an oxirane compound such as propylene oxide, butylene oxide, or tetrahydrofuran may be used. More specifically, the polyether polyol may have two or more functional groups such as polypropylene glycol, polyethylene glycol, and polytetramethylene glycol. The molecular weight of the polyether polyol is not particularly limited, and can be used from low molecular weight to high molecular weight. For example, a polyether polyol having a number average molecular weight of 1,000 to 15,000 may be used. When the number average molecular weight is 1,000 or more, the reactivity is too high and it is easy to prevent gelation. Moreover, when the number average molecular weight is 15,000 or less, it is easy to prevent a decrease in reactivity and a decrease in cohesive force of the polyurethane polyol itself. The polyether polyol may or may not be used, but the amount used may be, for example, 20 to 100 mol% or 20 to 80 mol% of the polyols constituting the polyurethane polyol.

The polyether polyol may be partially ethylene glycol, 1,4-butanediol, neopentyl glycol, butylethylpentanediol, glycerin, trimethylolpropane, pentaerythritol, glycols, ethylenediamine, N-, if necessary. Substituted with polyvalent amines such as aminoethylethanolamine, isophoronediamine, and xylenediamine may be used in combination.

As described above, the polyol may be a polyfunctional polyether polyol (having two hydroxyl groups in one molecule), but is preferably trifunctional or higher (having three or more hydroxyl groups in one molecule). In particular, the number average molecular weight is 1,000 to 15,000, and by using part or all of the polyol having trifunctionality or more, the balance between the adhesion and removability is more likely to be taken. When the number average molecular weight is 1,000 or more, the reactivity of the polyol having a trifunctional or higher function is too high to prevent gelation. Moreover, when the number average molecular weight is 15,000 or less, it is easy to prevent a decrease in the reactivity of a polyol having a trifunctional or higher function and a decrease in the cohesive force of the polyurethane polyol itself. For example, a polyol having a number average molecular weight of 2,500 to 3,500 and trifunctional or higher may be used in whole or in part.

The polyisocyanate (organic polyisocyanate compound) as a raw material of the urethane prepolymer (A) is not particularly limited, and examples thereof include known aromatic polyisocyanates, aliphatic polyisocyanates, aromatic aliphatic polyisocyanates, and alicyclic polyisocyanates. Can be. Moreover, you may use only 1 type and multiple types of polyisocyanate may be used together.

Examples of the aromatic polyisocyanate include 1,3-phenylene diisocyanate, 4,4'-diphenyl diisocyanate, 1,4-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, and 2,4. -Trilene diisocyanate, 2,6-triylene diisocyanate, 4,4'-toluidine diisocyanate, 2,4,6-triisocyanate toluene, 1,3,5-triisocyanatebenzene, dianisidine diisocyanate, 4,4 And '-diphenyl ether diisocyanate, 4,4', 4 "-triphenylmethane triisocyanate.

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

Examples of the aromatic aliphatic polyisocyanate include ω, ω'-diisocyanate-1,3-dimethylbenzene, ω, ω'-diisocyanate-1,4-dimethylbenzene, ω, ω'-diisocyanate-1 And 4-diene benzene, 1,4-tetramethylxylenediisocyanate, and 1,3-tetramethylxylenediisocyanate.

Examples of the alicyclic polyisocyanate include 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate, 1,3-cyclopentane diisocyanate, 1,3-cyclohexanediisocyanate, and 1,4-cyclo Hexanediisocyanate, methyl-2 4-cyclohexanediisocyanate, methyl-2,6-cyclohexanediisocyanate, 4,4'-methylenebis (cyclohexylisocyanate), 1,4-bis (isocyanatemethyl) cyclohexane, And 1,4-bis (isocyanate methyl) cyclohexane.

In addition, a trimethylolpropane adduct of some of the polyisocyanates, a burette that reacts with water, and a trimer having an isocyanurate ring 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.

It does not specifically limit as said catalyst, For example, a well-known catalyst can be used. Examples of the catalyst include tertiary amine compounds and organometallic compounds.

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

Examples of the organometallic compound include a tin-based compound and a non-tin-based compound. Examples of the tin-based compound include dibutyl tin dichloride, dibutyl tin oxide, dibutyl tin dibromide, dibutyl tin dimaleate, dibutyl tin dilaurate (DBTDL), dibutyl tin diacetate, Dibutyl tin sulfide, tributyl tin sulfide, tributyl tin oxide, tributyl tin acetate, triethyl tin ethoxide, tributyl tin ethoxide, dioctyl tin oxide, dioctyl tin dilaurate, tributyl And tin chloride, tributyltin trichloroacetate, and 2-ethylhexanoate. Examples of the non-tin-based compound include lead-based compounds such as titanium, such as dibutyl titanium dichloride, tetrabutyl titanate, butoxytitanium trichloride, lead oleate, lead 2-ethylhexanoate, lead benzoate, and lead naphthenate (鉛 系), iron-based 2-ethylhexanoate, iron-acetylacetonate, cobalt benzoate, cobalt 2-ethylhexanoate, zinc naphthenate, zinc 2-ethylhexanoate, zirconium naphthenate And the like.

When these catalysts are used, for example, in a system in which two types of polyols such as polyester polyol and polyether polyol are present, gelation occurs in the system of a single catalyst due to the difference in reactivity, or the reaction solution becomes turbid. It is easy to cause problems. In such a case, for example, by using two or more kinds of catalysts in combination, the reaction rate and selectivity of the catalyst can be controlled, and these problems can be solved. As the combination, for example, tertiary amine / organic metal-based, tin-based / non-tin-based, tin-based / tin-based, etc. are used, preferably tin-based / tin-based, more preferably dibutyltin-dilaurate And 2-ethylhexanoate. Although the mixing ratio is not particularly limited, for example, 2-ethylhexanoate / dibutyltin dilaurate in a mass ratio is less than 1, and may be, for example, 0.2 to 0.6. When the compounding ratio (mass ratio) is less than 1, it is easy to prevent gelation due to the balance of catalytic activity. The amount of the catalyst used is not particularly limited, but is, for example, 0.01 to 1.0% by mass or 0.01 to 0.2% by mass relative to the total amount of the polyol and the organic polyisocyanate.

When using the catalyst, the reaction temperature of the polyurethane polyol synthesis may be, for example, less than 100 ° C or 40 ° C to 60 ° C. When it is less than 100 ° C, it is easy to control the reaction rate and the crosslinked structure, and it is easy to obtain a polyurethane polyol having a predetermined molecular weight.

In addition, when the catalyst is not used (no catalyst), the reaction temperature of the polyurethane polyol synthesis may be, for example, 100 ° C or higher, or 110 ° C or higher. In addition, under the absence of a catalyst, the reaction time of the polyurethane polyol synthesis is, for example, 3 hours or more.

The solvent used for the synthesis of the urethane prepolymer (A) is not particularly limited, and, for example, a known solvent can be used. As said solvent, 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, are mentioned, for example. Toluene is particularly preferred from the viewpoint of solubility of the polyurethane polyol, boiling point of the solvent, and the like.

Moreover, although it does not specifically limit as said antioxidant, For example, antioxidants, such as a phenol type and a sulfur type, are mentioned.

In addition, in this invention, the molecular weight of a urethane prepolymer (A), molecular weight dispersion degree, etc. are not specifically limited. When the number average molecular weight of the urethane prepolymer (A) is determined, the molecular weight of each of the polyisocyanates and polyols used as a raw material for the production of the urethane prepolymer (A), and the reaction ratio (NCO / OH equivalent ratio) between the polyisocyanate and the polyol is determined. It can be calculated theoretically (Japanese Patent Publication No. 2017-025147).

[3.Adhesive sheet and its manufacturing method, use, etc.]

Next, the pressure-sensitive adhesive sheet of the present invention and its manufacturing method, use, etc. will be described, for example.

As described above, the pressure-sensitive adhesive sheet of the present invention is a pressure-sensitive adhesive sheet having an adhesive layer formed on at least one surface of a substrate, and the pressure-sensitive adhesive layer is an adhesive layer formed of the pressure-sensitive adhesive of the present invention. Although the manufacturing method is not specifically limited, For example, it can be manufactured by the manufacturing method of this invention (the manufacturing method of the adhesive sheet of this invention).

The manufacturing method of the pressure-sensitive adhesive sheet of the present invention, as described above, a coating step of coating the pressure-sensitive adhesive of the present invention on the pressure-sensitive adhesive layer forming surface of the substrate, the pressure-sensitive adhesive layer is formed, and after the coating step, the pressure-sensitive adhesive layer It is a method of manufacturing the pressure-sensitive adhesive sheet of the present invention, comprising a heating step of heating the pressure-sensitive adhesive on the formation surface. Hereinafter, a method for producing the pressure-sensitive adhesive sheet of the present invention will be mainly described, for example, when the urethane prepolymer (A) contains a polyurethane polyol synthesized from polyol and polyisocyanate.

That is, first, the pressure-sensitive adhesive of the present invention is coated on the pressure-sensitive adhesive layer forming surface of the substrate on which the pressure-sensitive adhesive layer is formed (coating step). The base material is not particularly limited, and examples thereof include plastic, polyurethane, paper, and metal foil, but plastic is preferred. As said plastic, PET (polyethylene terephthalate), PE (polyethylene), PP (polypropylene), PC (polycarbonate), etc. are mentioned, for example.

The shape of the substrate is not particularly limited, and examples thereof include sheets, films, foams, and the like. It is preferable that the said base material is a long tape shape which can be wound up, for example from a viewpoint of easiness of handling of the adhesive sheet after manufacture, easiness of storage, etc.

In addition, the base material may be, for example, a base material subjected to an easy-adhesive treatment on the adhesive layer-forming surface of the base material as needed. Although the said easily adhesive treatment is not specifically limited, Specifically, the method of processing a corona discharge, the method of apply | coating an anchor coat agent etc. are mentioned, for example.

When the pressure-sensitive adhesive of the present invention does not contain a crosslinking agent (C), for example, it is preferable to mix the crosslinking agent (C) prior to the coating step. When the crosslinking agent (C) contains a polyisocyanate, the polyisocyanate is not particularly limited, but is reacted with the polyisocyanate exemplified in the above "2. Method for producing an adhesive", and a trimethylolpropane adduct, water A burette body, a trimer having an isocyanurate ring, etc. are mentioned, You may use together 1 type and multiple types together. The amount of the crosslinking agent (C) used is as described above, for example. Further, for the purpose of easily mixing the pressure-sensitive adhesive and the crosslinking agent (C) of the present invention, or for the purpose of easily coating the substrate, a solvent may be mixed prior to the coating step. The type of the solvent and the like are not particularly limited, but, for example, it is the same as the solvent exemplified in the above "2. Adhesive manufacturing method", and may be used alone or in combination.

The coating method in the said coating process is not specifically limited, A well-known method may be sufficient. 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.

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, 5 to 30 μm, 7 to Let it be 20 micrometers or 10-15 micrometers.

In addition, after the coating step, the pressure-sensitive adhesive is heated on the adhesive layer forming surface (heating step). In addition, hereafter, in order to distinguish the said heating process from the 2nd heating process mentioned later, it may be called "the 1st heating process." Although the heating temperature in the said heating process (1st heating process) is not specifically limited, For example, it is 60 degreeC or more, the temperature exceeding 60 degreeC, 90 degreeC or more, or the temperature exceeding 90 degreeC, or It is 100 degreeC or more, or 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 adhesive layer from coming off from the end of the base material during storage or handling of the adhesive sheet, it is preferable to increase the heating temperature in the heating step as much as possible. It is presumed that by making the heating temperature as high as possible, for example, the cross-linking (curing) reaction between the pressure-sensitive adhesive and the cross-linking agent (C) of the present invention is easy to proceed sufficiently, so that it is possible to prevent the swelling. However, this mechanism is speculation, and the present invention is not limited at all.

Generally, when the heating temperature after coating the pressure-sensitive adhesive on the substrate is too high, there is a fear that the adhesion of the pressure-sensitive adhesive layer to the substrate is reduced. On the other hand, according to the pressure-sensitive adhesive of the present invention, even when heated at a high temperature, for example, the adhesion to the substrate is good, and it is possible to prevent rebounding and protruding from the substrate.

In addition, the heating time in the heating step (first heating step) is not particularly limited, but, for example, drying (removal of the solvent) of the coated adhesive is sufficient, and the substrate is damaged by heat. It is desirable that the time is not enough. Although the said specific heating time depends on the kind of the said solvent and the said base material etc., it is 30-240 second, or 60-180 second, for example.

Moreover, in the manufacturing method of the adhesive sheet by this invention, it is preferable to include the 2nd heating process which heats to a temperature lower than the said heating process after the said heating process (1st heating process). Although it is not necessary to perform the said 2nd heating process even if it does, by doing this, the sticking-off of the adhesive layer from the edge of the said base material can be prevented more effectively. The phenomenon occurring in the second heating step is not clear, but it is presumed that, for example, curing (crosslinking) of the adhesive layer is further progressing. However, this guess does not limit the present invention at all. Although the heating temperature in the said 2nd heating process is not specifically limited, For example, it is 30-50 degreeC, or 35-45 degreeC. The heating time in the second heating step is not particularly limited, but is, for example, 24 to 120 hr or 48 to 96 hr.

The use of the pressure-sensitive adhesive sheet of the present invention is not particularly limited, but as described above, it is preferable to use it as a protective sheet for the image display surface by attaching it to the image display surface of the image display device. Moreover, when it uses 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 characterized in that the protective sheet is the pressure-sensitive adhesive sheet of the present invention, as the image display device with the protective sheet of the image display device attached to the image display surface. The image display device is not particularly limited, and examples thereof include a mobile phone, a smart phone, and a tablet computer. However, the use of the pressure-sensitive adhesive sheet of the present invention is not limited to an image display device, and can also be used as a protective sheet for windowpanes such as automobiles and buildings. In addition, the pressure-sensitive adhesive sheet of the present invention is not limited to, for example, glass, and can also be used as a protective sheet for ITO (Indium Tin Oxide) processed on a glass substrate as a transparent conductive film. Moreover, the use of the adhesive sheet of this invention is not limited to these, For example, it can be widely used for uses, such as a general adhesive sheet, an adhesive film, an adhesive tape, etc. Since the pressure-sensitive adhesive sheet of the present invention does not contaminate the adherend after peeling even when exposed to, for example, wet heat, it is excellent in wettability, and also excellent in adhesion between the pressure-sensitive adhesive and the substrate, so that As one can be used for a wide range of applications. In addition, the use of the pressure-sensitive adhesive of the present invention is also not particularly limited to the pressure-sensitive adhesive sheet of the present invention, and can be widely used, for example, in applications such as general pressure-sensitive adhesives.

The shape of the pressure-sensitive adhesive sheet of the present invention is also not particularly limited, but for example, upon storage, a separator is attached to the pressure-sensitive adhesive layer to protect the pressure-sensitive adhesive layer, and immediately before use (for example, attachment to an image display device, etc.) It is preferable to peel the separator. Further, for example, the pressure-sensitive adhesive sheet of the present invention is a long tape-like shape that can be wound, and it is preferable to wind up and store it. According to the pressure-sensitive adhesive tape of the present invention, it is possible to prevent the pressure-sensitive adhesive layer from coming off from the end of the pressure-sensitive adhesive tape, for example, during winding up and storage.

[Example]

Hereinafter, examples of the present invention will be described. In addition, the present invention is not limited to these examples.

The raw material names (compound names) used in the following examples and comparative examples, and their product names (brand names) and manufacturers, are collectively shown in Table 1 below.

[Table 1]

[Synthesis Example 1]

According to the following procedure, a urethane prepolymer (A) was synthesized to prepare a urethane prepolymer (A) solution.

Glycerin PO · EO, hexamethylene diisocyanate, toluene, and DBTDL were placed in a separable flask equipped with a stirrer, reflux cooling tube, and thermometer, and reacted at 60 ° C. for 3 hours with stirring. When the NCO group of the content after the reaction was measured using an infrared spectrophotometer (IR), the residual of the NCO group could not be confirmed. Thereby, it was confirmed that the synthesis of the urethane prepolymer (A) was completed. Then, the contents were cooled to 40 ° C or lower, and antioxidant and ethyl acetate were added to prepare a urethane prepolymer (A) solution. This solution was used in the following examples and comparative examples. In addition, "Liseline PO.EO" represents the propylene oxide and ethylene oxide adducts of glycerin, and "DBTDL" represents dibutyl tin dilaurate.

[Synthesis Example 2]

A urethane prepolymer (A) was synthesized in the same manner as in Synthesis Example 1, except that glycerin PO was used instead of glycerin PO · EO to prepare a urethane prepolymer (A) solution. In addition, "glycerin PO" represents the propylene oxide adduct of glycerin.

[Synthesis Example 3]

As a polyol, a urethane prepolymer (A) was synthesized in the same manner as in Synthesis Example 1, except that a pluronic polyol was used in addition to glycerin PO · EO to prepare a urethane prepolymer (A) solution. In addition, "Pluronic polyol" represents the ethylene oxide adduct of polypropylene glycol.

[Synthesis Example 4]

As a polyol, a urethane prepolymer (A) was synthesized in the same manner as in Synthesis Example 1, except that polypropylene glycol was used in addition to glycerin PO · EO to prepare a urethane prepolymer (A) solution.

[Synthesis Example 5]

A urethane prepolymer (A) was synthesized in the same manner as in Synthesis Example 1 except that 4,4'-diphenylmethane diisocyanate was used instead of hexamethylene diisocyanate to prepare a urethane prepolymer (A) solution.

[Synthesis Example 6]

As a polyol, a urethane prepolymer (A) was synthesized in the same manner as in Synthesis Example 5, except that a molecular weight of glycerin PO was changed to 4,000, to prepare a urethane prepolymer (A) solution.

[Synthesis Example 7]

As a polyol, a urethane prepolymer (A) was synthesized in the same manner as in Synthesis Example 2, except that a molecular weight of glycerin PO was changed to 10,000, to prepare a urethane prepolymer (A) solution.

The component amounts (parts by mass) of each component used in the synthesis of the urethane prepolymer (A) in the Synthesis Examples 1 to 7 and the preparation of the urethane prepolymer (A) solution are collectively shown in Table 2 below.

[Table 2]

[Example 1]

100 parts by mass of the urethane prepolymer solution of Synthesis Example 1 (60 parts by mass as a solid content), 3 parts by mass of p-toluenesulfonate (nonionic sulfonic acid ester (B)), and an isocyanurate body of hexamethylene diisocyanate (crosslinking agent (C ), Asahi Chemical Co., Ltd., trade name Duranate TKA-100) 6 parts by mass, and stirred well as the pressure-sensitive adhesive (coating solution) of Example 1.

[Example 2]

An adhesive was prepared in the same manner as in Example 1 except that the urethane prepolymer solution of Synthesis Example 2 was used instead of the urethane prepolymer solution of Synthesis Example 1.

[Example 3]

An adhesive was prepared in the same manner as in Example 1 except that the urethane prepolymer solution of Synthesis Example 3 was used instead of the urethane prepolymer solution of Synthesis Example 1.

[Example 4]

An adhesive was prepared in the same manner as in Example 1 except that the urethane prepolymer solution of Synthesis Example 4 was used instead of the urethane prepolymer solution of Synthesis Example 1.

[Example 5]

An adhesive was prepared in the same manner as in Example 1 except that the urethane prepolymer solution of Synthesis Example 5 was used instead of the urethane prepolymer solution of Synthesis Example 1.

[Example 6]

An adhesive was prepared in the same manner as in Example 1 except that the urethane prepolymer solution of Synthesis Example 6 was used instead of the urethane prepolymer solution of Synthesis Example 1.

[Example 7]

An adhesive was prepared in the same manner as in Example 1 except that the urethane prepolymer solution of Synthesis Example 7 was used instead of the urethane prepolymer solution of Synthesis Example 1.

[Example 8]

An adhesive was prepared in the same manner as in Example 1 except that the addition amount of p-toluenesulfonic acid methyl (nonionic sulfonic acid ester (B)) was changed to 1 part by mass.

[Example 9]

As a nonionic sulfonic acid ester (B), an adhesive was prepared in the same manner as in Example 1, except that ethyl p-toluenesulfonate of the same mass was used instead of methyl p-toluenesulfonic acid.

[Example 10]

An adhesive was prepared in the same manner as in Example 9 except that the addition amount of p-toluenesulfonate (nonionic sulfonic acid ester (B)) was changed to 1 part by mass.

[Example 11]

As a nonionic sulfonic acid ester (B), an adhesive was prepared in the same manner as in Example 1 except that n-octyl p-toluenesulfonic acid was used in place of methyl p-toluenesulfonic acid.

[Example 12]

An adhesive was prepared in the same manner as in Example 11 except that the addition amount of p-toluenesulfonic acid n-octyl (nonionic sulfonic acid ester (B)) was changed to 1 part by mass.

[Example 13]

As a nonionic sulfonic acid ester (B), a pressure-sensitive adhesive was prepared in the same manner as in Example 8, except that 1,3-bis (tosyloxy) propane of the same mass was used instead of methyl p-toluenesulfonate.

[Example 14]

An adhesive was prepared in the same manner as in Example 8, except that 30 parts by mass of the carboxylic acid ester represented by the following formula (1001) (n is an average of 12) was also blended.

[Formula 1001]

[Example 15]

An adhesive was prepared in the same manner as in Example 14 except that the addition amount of p-toluenesulfonic acid methyl (nonionic sulfonic acid ester (B)) was changed to 0.5 parts by mass.

[Example 16]

An adhesive was prepared in the same manner as in Example 14 except that the addition amount of p-toluenesulfonic acid methyl (nonionic sulfonic acid ester (B)) was changed to 0.25 parts by mass.

[Example 17]

An adhesive was prepared in the same manner as in Example 8, except that 30 parts by mass of the carboxylic acid ester represented by the following formula (1010) (n is an average of 10) was also blended.

[Formula 1010]

[Example 18]

In place of 6 parts by mass of the isocyanurate body of the hexamethylene diisocyanate of Example 14 (crosslinking agent (C), Asahi Chemical Co., Ltd., trade name Duranate TKA-100), a burette body of hexamethylene diisocyanate (Asahi Chemical Co., Ltd.) The adhesive was manufactured in the same manner as in Example 14, except that 6 parts by mass of Duranate 24A-100) was used.

[Example 19]

The bifunctional type of hexamethylene diisocyanate (Asahi Chemical Co., Ltd.) in place of 6 parts by mass of the isocyanurate body of the hexamethylene diisocyanate of Example 14 (crosslinking agent (C), Asahi Chemical Co., Ltd., trade name Duranate TKA-100) , Trade name Duranate D101) An adhesive was prepared in the same manner as in Example 14 except that 7 parts by mass was used.

[Example 20]

An adduct of toluene diisocyanate (Tosoh Corporation, brand name) in place of 6 parts by mass of the isocyanurate body of the hexamethylene diisocyanate of Example 14 (crosslinking agent (C), Asahi Chemical Co., Ltd., trade name Duranate TKA-100) Coronate L) An adhesive was prepared in the same manner as in Example 14 except that 10 parts by mass was used.

[Example 21]

Non-yellowing of hexamethylene diisocyanate in place of 6 parts by mass of the isocyanurate of hexamethylene diisocyanate of Example 14 (crosslinking agent (C), Asahi Chemical Co., Ltd., trade name Duranate TKA-100) An adhesive was prepared in the same manner as in Example 14 except that 11 parts by mass of type (Tosoh Corporation, trade name Coronate HL) was used.

[Example 22]

An adduct of xylene diisocyanate (Mitsui Chemicals Co., Ltd.) in place of 6 parts by mass of the isocyanurate body of the hexamethylene diisocyanate of Example 14 (crosslinking agent (C), Asahi Chemical Co., Ltd., trade name Duranate TKA-100) A pressure-sensitive adhesive was prepared in the same manner as in Example 14, except that 12 parts by mass of Takenate D-110N) was used.

[Example 23]

An adduct of isophorone diisocyanate (Mitsui Chemicals Co., Ltd.) in place of 6 parts by mass of the isocyanurate body of the hexamethylene diisocyanate of Example 14 (crosslinking agent (C), Asahi Chemical Co., Ltd., trade name Duranate TKA-100) , Product name Takenate D-140N) An adhesive was prepared in the same manner as in Example 14 except that 13 parts by mass was used.

[Example 24]

The isocyanurate body of toluene diisocyanate (Mitsui Chemicals) in place of 6 parts by mass of the isocyanurate body of the hexamethylene diisocyanate of Example 14 (crosslinking agent (C), Asahi Chemical Co., Ltd., trade name Duranate TKA-100) A pressure-sensitive adhesive was prepared in the same manner as in Example 14, except that 18 parts by mass of Co., Ltd. brand name Takenate D-262) was used.

[Comparative Example 1]

An adhesive was prepared in the same manner as in Example 1, except that p-toluenesulfonate methyl (nonionic sulfonic acid ester (B)) was not blended.

[Comparative Example 2]

An adhesive was prepared in the same manner as in Comparative Example 1, except that 1 part by mass of the carboxylic acid ester represented by the formula (1010) (n is an average of 10) was also blended.

[Comparative Example 3]

An adhesive was prepared in the same manner as in Comparative Example 1, except that 30 parts by mass of the carboxylic acid ester represented by the formula (1010) (n is an average of 10) was also blended.

With respect to the adhesives of Examples and Comparative Examples prepared as described above, the adhesive force (peeling force), wettability, and adherend contamination were evaluated by the following methods. The results are summarized in Tables 3 and 4 below.

1. Adhesion

For evaluation of the adhesive force, an adhesive sheet prepared by coating a coating solution (adhesive) on a PET film having a thickness of 50 µm was used as a sample. In an environment of 23 ° C. x 50% RH humidity, the sample was cut to a width of 25 mm and bonded to the adherend (glass plate) with a load of 3 reciprocating rollers of 2 kg. After curing for 1 hour, the peel force (N / 25 mm) when one end of the sample was peeled off with an autograph at a rate of 300 mm / min in the 180 ° direction was used as the adhesive force. The peeling force as the pressure-sensitive adhesive sheet is preferably not excessively large, and preferably 0.1 N / 25 mm or less, from the viewpoint of removability.

2. Wetting

For evaluation of wettability, an adhesive sheet prepared by coating a coating solution on a PET film having a thickness of 50 µm was used as a sample. The sample was cut to 5 cm × 10 cm, and only one side of the width of 5 cm of the sample was brought into contact with the glass plate at a 45 ° tilt. Thereafter, hands were released, and the time (seconds) required for the entire surface of the sample to contact the glass plate (wet the glass plate) was evaluated as wettability. The shorter the time (second), the higher the wettability (adhesiveness) of the glass plate. The higher the wettability, the faster the adherend (the glass plate in this embodiment) can be joined. The wettability is preferably 10 seconds / 10 cm or less.

3. Endothelial body Pollution

For evaluation of the adherend contamination, an adhesive sheet prepared by coating a coating solution on a PET film having a thickness of 50 µm was used as a sample. The sample was cut to 4 cm x 10 cm, and an adhesive sheet was bonded to a glass plate or PET film. This was allowed to stand for 72 hours in a thermo-hygrostat with 80 ° C x 80% RH humidity, and then left for 1 hour under an environment of 23 ° C x 50% RH humidity. Next, the pressure-sensitive adhesive sheet was peeled from the glass plate or PET film, and the state of white contamination of the glass surface of the portion where the pressure-sensitive adhesive sheet was bonded was visually evaluated, and this was used as the evaluation result of adherend contamination. In addition, the state of white contamination was evaluated by irradiating white light in the dark.

(Results of evaluating adherend contamination)

?: No white contaminants were observed on the glass surface.

(Circle): A white stain was observed on a part of the glass surface.

Δ: A white contaminant was observed on the glass surface in a stain shape.

×: White contaminants were observed on the entire surface of the glass.

[Table 3]

[Table 4]

As shown in Tables 3 and 4, the pressure-sensitive adhesives of Examples 1 to 24 including all of the components (A) to (C) had good adhesion (removability), wettability, and adherend contamination. That is, the adhesives of Examples 1 to 24 were able to satisfy all of the removability, wettability, and adherend contamination. On the other hand, the adhesives of Comparative Examples 1 to 3 not containing the nonionic sulfonic acid ester (B) had good adhesive strength (removability) and wettability, but the adherend contamination was inferior to that of the Examples.

[Industrial availability]

As described above, according to the present invention, it is possible to provide a pressure-sensitive adhesive, a pressure-sensitive adhesive sheet, a method for manufacturing the pressure-sensitive adhesive sheet, and an image display device capable of satisfying re-peelability, wettability, and adherend contamination under high temperature and high humidity. The pressure-sensitive adhesive, the pressure-sensitive adhesive sheet of the present invention, and the manufacturing method of the pressure-sensitive adhesive sheet can be used, for example, as a protective sheet for windowpanes such as mobile phones, smart phones, automobiles, buildings, and the like. In addition, the present invention is not limited to this, and can be widely used in various applications, and for example, it is widely applicable to fields in which a general pressure-sensitive adhesive, a pressure-sensitive adhesive sheet and a method of manufacturing the pressure-sensitive adhesive sheet are used.

Claims (6)

A pressure-sensitive adhesive comprising a urethane prepolymer (A) having a hydroxyl group and a nonionic sulfonic acid ester (B). According to claim 1,
The pressure-sensitive adhesive, characterized in that the urethane prepolymer (A) is an adduct of polyol and isocyanate. The method according to claim 1 or 2,
In addition, a pressure-sensitive adhesive comprising a crosslinking agent (C), wherein the crosslinking agent (C) is a polyisocyanate. An adhesive sheet in which an adhesive layer is formed on at least one surface of a base material, wherein the adhesive layer is an adhesive layer formed of the adhesive according to any one of claims 1 to 3. A coating step of coating the pressure-sensitive adhesive according to any one of claims 1 to 3 on the pressure-sensitive adhesive layer formation surface on which the pressure-sensitive adhesive layer is formed,
After the coating step, a method of manufacturing the pressure-sensitive adhesive sheet according to claim 4, comprising a heating step of heating the pressure-sensitive adhesive on the pressure-sensitive adhesive layer forming surface. As an image display device with a protective sheet of the image display device attached to the image display surface,
An image display device characterized in that the protective sheet is the adhesive sheet according to claim 4.