CN111032813B

CN111032813B - Urethane adhesive and adhesive sheet

Info

Publication number: CN111032813B
Application number: CN201980003934.1A
Authority: CN
Inventors: 户根嘉孝; 斋藤秀平; 田邉慎吾
Original assignee: Toyo Ink SC Holdings Co Ltd; Toyochem Co Ltd
Current assignee: Toyochem Co Ltd; Artience Co Ltd
Priority date: 2018-08-29
Filing date: 2019-07-17
Publication date: 2021-12-21
Anticipated expiration: 2039-07-17
Also published as: KR20210049716A; WO2020044829A1; TWI808226B; JP6516056B1; TW202020090A; JP2020033434A; CN111032813A

Abstract

The invention provides a urethane adhesive and an adhesive sheet, which have reduced adhesive force even in the initial stage (before time lapse) and after time lapse (especially after (wet) heat time lapse), have good re-peeling property, and can form an adhesive layer with less contamination of an adherend after re-peeling. The adhesive of the invention is a carbamate adhesive, comprising: one or more active hydrogen group-containing compounds (H) having a plurality of active hydrogen groups in one molecule, one or more polyfunctional isocyanate compounds (I), and one or more surfactants (S) having a cationic hydrophilic group, wherein the amine value of the surfactant (S) is 0.1mgKOH/g to 150mgKOH/g in terms of nonvolatile components, and the content of the surfactant (S) is 0.01 parts by mass to 20 parts by mass relative to 100 parts by mass of the active hydrogen group-containing compound (H).

Description

Urethane adhesive and adhesive sheet

Technical Field

The present invention relates to a urethane adhesive and an adhesive sheet.

Background

An adhesive sheet having an adhesive layer formed on a base sheet has been widely used as a surface protection sheet for various members since now. Examples of the adhesive include acrylic adhesives, silicone adhesives, and urethane adhesives. The acrylic pressure-sensitive adhesive has excellent adhesive strength, but has poor removability after being stuck to an adherend because of its strong adhesive strength. In particular, after a lapse of time in a (wet) hot environment, the removability further decreases due to an increase in adhesive force, and the adherend tends to be contaminated by the adhesive remaining on the surface of the adherend after removability. Silicone adhesives tend to stain adherends, and silicone resins having relatively low molecular weights may volatilize and adsorb on the surfaces of devices such as electronic components, thereby causing problems. In contrast, the urethane adhesive has good adhesion to an adherend, is relatively excellent in removability, and is also difficult to volatilize.

In the present specification, "adhesive" refers to an adhesive having releasability (removable adhesive), and "adhesive sheet" refers to an adhesive sheet having releasability (removable adhesive sheet).

Flat panel displays such as Liquid Crystal Displays (LCDs) and organic electroluminescent displays (OELDs), and touch panel displays in which the flat panel displays and a touch panel are combined are widely used in electronic devices such as Televisions (TVs), Personal Computers (PCs), mobile phones, and portable information terminals.

The urethane adhesive sheet is preferably used as a surface protection sheet for flat panel displays, touch panel displays, substrates manufactured or used in these manufacturing steps (glass substrates, ITO/glass substrates having an Indium Tin Oxide (ITO) film formed on a glass substrate, and the like), optical members, and the like.

As a method for producing a urethane adhesive, there are a method of using a hydroxyl-terminated urethane prepolymer, which is a reaction product of an active hydrogen group-containing compound such as a polyol and a polyisocyanate, and a polyfunctional isocyanate compound, and a method of reacting an active hydrogen group-containing compound such as a polyol and a polyfunctional isocyanate compound once without using a hydroxyl-terminated urethane prepolymer (one shot).

A general method for producing an adhesive sheet includes: a coating step of coating an adhesive on a substrate sheet; a heating step of forming an adhesive layer containing a cured product of an adhesive by heating and drying the formed coating layer; a winding step of winding the obtained adhesive sheet around a winding core to form an adhesive sheet roll; and a curing step of curing the adhesive sheet roll.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2014-162821

Patent document 2: japanese patent laid-open No. 2018-062628

Patent document 3: japanese patent laid-open No. 2015-172202

Patent document 4: japanese patent laid-open publication No. 2011-037928

Disclosure of Invention

Problems to be solved by the invention

Although the urethane adhesive is cured immediately after production, if the initial curing property is low, the coating layer or the adhesive layer is affected by hot air during heating and drying of the coating layer or mechanical stress during winding and curing of the adhesive sheet obtained after heating and drying, and surface appearance defects such as a core step mark, orange peel, and a curl mark may occur in the adhesive layer. The urethane adhesive preferably has a good pot life (pot life) and good initial curability.

The pressure-sensitive adhesive sheet preferably has good removability to be easily removable from an adherend when it is unloaded from the adherend, in both the initial stage (before lapse of time) and the post-lapse stage (particularly after lapse of (moist) heat). In general, when an adhesive sheet is exposed to a (moist) heat environment, the adhesiveness between an adherend and an adhesive layer is increased, and as a result, the adhesive force of the adhesive layer tends to increase and the removability tends to decrease. Even when the adhesive sheet is exposed to a (moist) heat environment, it is preferable that the re-peelability is good and there is no adherend contamination in which an adhesive component remains on the surface of the adherend after re-peeling.

As the related documents of the present invention, patent documents 1 to 4 will be described in detail later.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an adhesive which has good initial curability, reduced adhesive force even in either the initial stage (before time elapses) or after time elapses (particularly after (wet) heat elapses), good removability, and can form an adhesive layer with less contamination of an adherend after removability, and an adhesive sheet using the same.

Means for solving the problems

The adhesive of the invention is a carbamate adhesive, comprising:

one or more active hydrogen group-containing compounds (H) having a plurality of active hydrogen groups in one molecule,

At least one polyfunctional isocyanate compound (I) and

one or more surfactants (S) having a cationic hydrophilic group,

the surfactant (S) has an amine value of 0.1mgKOH/g to 150mgKOH/g in terms of nonvolatile matter,

the content of the surfactant (S) is 0.01 to 20 parts by mass with respect to 100 parts by mass of the active hydrogen group-containing compound (H).

The adhesive sheet of the present invention comprises: a substrate sheet, and an adhesive layer containing a cured product of the adhesive of the present invention.

In the present specification, "Mw" is a polystyrene-equivalent weight average molecular weight determined by Gel Permeation Chromatography (GPC) measurement. "Mn" is a number average molecular weight in terms of polystyrene determined by GPC measurement. These can be measured by the method described in "example".

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, there can be provided an adhesive which has good initial curability, reduced adhesive force even in both initial (before) and after (particularly after (wet) heat aging), good re-peelability, and can form an adhesive layer with little contamination of an adherend after re-peeling, and an adhesive sheet using the same.

Drawings

FIG. 1 is a schematic cross-sectional view of an adhesive sheet according to a first embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view of an adhesive sheet according to a second embodiment of the present invention.

Detailed Description

[ urethane adhesive ]

The adhesive of the invention is a carbamate adhesive, comprising:

one or more active hydrogen group-containing compounds (H) having a plurality of active hydrogen groups in one molecule, one or more polyfunctional isocyanate compounds (I), and one or more surfactants (S) having a cationic hydrophilic group.

In the adhesive of the present invention, the amine value of the surfactant (S) is 0.1mgKOH/g to 160mgKOH/g, preferably 0.1mgKOH/g to 150mgKOH/g, in terms of nonvolatile matter, and the content of the surfactant (S) is 0.01 parts by mass to 20 parts by mass relative to 100 parts by mass of the active hydrogen group-containing compound (H).

The adhesive sheet of the present invention is a urethane adhesive sheet, comprising: a substrate sheet, and an adhesive layer containing a cured product of the adhesive of the present invention.

The active hydrogen group-containing compound (H) is a compound having a plurality of active hydrogen groups in one molecule.

As the active hydrogen group, there can be mentioned: hydroxyl group (hydroxyl group), mercapto group, and amino group (amino group includes imino group unless otherwise specified in the present specification). As the active hydrogen group-containing compound (H), there can be mentioned: polyols having a plurality of hydroxyl groups in one molecule, polyamines having a plurality of amino groups in one molecule, aminoalcohols having amino groups and hydroxyl groups in one molecule, and polythiols having a plurality of mercapto groups in one molecule, and the like. These active hydrogen group-containing compounds (H) may be non-polymer or polymer. These may be used singly or in combination.

Among them, polyhydric alcohols are preferable. Polyamines and polythiols are highly reactive and have a short pot life, and therefore when these are used, they are preferably used in combination with polyols. In addition, in the case where the active hydrogen group of the polyol is a secondary hydroxyl group, the initial curing property of the urethane adhesive is not improved, and therefore, the polyol preferably contains a primary hydroxyl group having an appropriate reactivity in terms of pot life and initial curing property.

(hydroxyl-terminated Urethane Prepolymer (UPH))

The active hydrogen group-containing compound (H) is preferably a hydroxyl-terminated Urethane Prepolymer (UPH) which is a reaction product obtained by copolymerization of one or more active hydrogen group-containing compounds (HX) with one or more polyisocyanates (N). The copolymerization can be carried out in the presence of one or more catalysts, if desired. If necessary, one or more solvents may be used in the copolymerization reaction.

< Compound containing active Hydrogen group (HX) >

As the polyol that can be used as the active hydrogen group-containing compound (HX), there can be mentioned: polyester polyols, polyether polyols, polyacrylic polyols, polycaprolactone polyols, polycarbonate polyols, castor oil polyols, and the like. Among these, polyester polyols, polyether polyols, and combinations thereof are preferable.

As the polyester polyol that can be used as the active hydrogen group-containing compound (HX), a known polyester polyol can be used. Examples of the polyester polyol include compounds (esterified products) obtained by esterification of one or more polyol components and one or more acid components.

As the polyol component of the raw material, there can be mentioned: ethylene Glycol (EG), Propylene Glycol (PG), diethylene Glycol, 1, 3-butanediol, 1, 4-butanediol, neopentyl Glycol, 3-methyl-1, 5-pentanediol, 2-butyl-2-ethyl-1, 3-propanediol, 2, 4-diethyl-1, 5-pentanediol, 1, 2-hexanediol, 1, 6-hexanediol, 2-ethyl-1, 3-hexanediol (1, 3-octanediol), 1, 8-octanediol, 1, 9-nonanediol, 2-methyl-1, 8-octanediol, 1, 8-decanediol, octadecanediol, glycerol, trimethylolpropane, pentaerythritol, hexanetriol, and the like.

As the acid component of the raw material, there can be mentioned: succinic acid, methylsuccinic acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, 1, 12-dodecanedioic acid, 1, 14-tetradecanedioic acid, dimer acid, 2-methyl-1, 4-cyclohexanedicarboxylic acid, 2-ethyl-1, 4-cyclohexanedicarboxylic acid, phthalic acid, isophthalic acid, terephthalic acid, 1, 4-naphthalenedicarboxylic acid, 4' -biphenyldicarboxylic acid, anhydrides of these, and the like.

As the polyether polyol that can be used as the active hydrogen group-containing compound (HX), known polyether polyols can be used. The polyether polyol includes a compound (addition polymer) obtained by addition polymerization of one or more oxetane (oxolane) compounds using an active hydrogen group-containing compound having a plurality of active hydrogen groups in one molecule as an initiator.

Examples of the initiator include hydroxyl group-containing compounds and amines. Specifically, there may be mentioned: difunctional initiators such as Ethylene Glycol (EG), Propylene Glycol (PG), 1, 4-butanediol, neopentyl glycol, butylethylpentanediol, N-aminoethylethanolamine, isophoronediamine, and xylylenediamine; trifunctional initiators such as glycerin, trimethylolpropane and triethanolamine; tetrafunctional initiators such as pentaerythritol, ethylenediamine, and aromatic diamines; pentafunctional initiators such as diethylenetriamine, and the like.

Examples of the oxirane compound include: alkylene Oxides (AO) such as Ethylene Oxide (EO), Propylene Oxide (PO), and Butylene Oxide (BO); tetrahydrofuran (THF), and the like.

The polyether polyol is preferably an alkylene oxide adduct of an active hydrogen-containing compound (also referred to as polyoxyalkylene polyol). Among them, bifunctional polyether polyols such as Polyethylene Glycol (PEG), Polypropylene Glycol (PPG), PPG (PPG-EO) in which Ethylene Oxide (EO) is added to the end, and polyalkylene glycols such as polytetramethylene Glycol are preferable; and trifunctional polyether polyols such as alkylene oxide adducts of glycerin.

The unsaturation of the polyether polyol is preferably low. The degree of unsaturation is the total amount of unsaturation contained per 1g of polyether polyol, corresponding to the amount of impurity monool. By using a high-purity material having a low degree of unsaturation, the initial curing properties of the adhesive become good, and in particular, when the adhesive sheet is exposed to a (moist) heat environment, it is possible to suppress contamination of the adherend in which the adhesive component remains on the surface of the adherend after the adhesive sheet is peeled off again. The unsaturation degree of the polyether polyol is preferably 0.07meq/g or less, more preferably 0.04meq/g or less, and particularly preferably 0.01meq/g or less.

In the present specification, unless otherwise specified, the unsaturation degree of the polyol is a value measured in accordance with Japanese Industrial Standards (JIS) K15576.7.

As the polyamine that can be used as the active hydrogen group-containing compound (HX), there can be mentioned: ethylenediamine, 1, 2-propylenediamine, 1, 3-propylenediamine, 1, 4-butylenediamine, 1, 5-pentylenediamine, 1, 6-hexylenediamine, 1, 7-heptylenediamine, 1, 8-octylenediamine, 1, 9-nonylenediamine, 1, 10-decyldiamine, 1, 12-dodecyldiamine, 1, 14-tetradecylenediamine, 1, 16-hexadecyldiamine, hexamethylenediamine, trimethylhexamethylenediamine, iminobispropylamine, methyliminobispropylamine, 1, 5-diamino-2-methylpentane, isophoronediamine, 1, 3-bisaminomethylcyclohexane, 1-cyclohexylamino-3-aminopropane, 3-aminomethyl-3, 3, 5-trimethyl-cyclohexylamine, 1, 4-butylenediamine, 1, 5-tetramethylenediamine, 1, 6-dodecyldiamine, 1, 14-tetradecylenediamine, 1, 16-hexadecyldiamine, hexamethylenediamine, trimethylhexamethylenediamine, iminobispropylamine, 1, 5-trimethyl-cyclohexylamine, 3-aminopropane, 3-aminomethyl-cyclohexylamine, 2-diamine, and mixtures thereof, Aliphatic polyamines such as dimethylene amine with a norbornane skeleton, m-xylylenediamine (MXDA), hexamethylene diamine carbamate, diethylene triamine, triethylene tetramine, tetraethyl pentamine, and pentaethylene hexamine; aromatic polyamines such as 3, 3 '-dichloro-4, 4' -diaminodiphenylmethane (MOCA), 4 '-diaminodiphenylmethane, 2, 4' -diaminodiphenylmethane, 3 '-diaminodiphenylmethane, 3, 4' -diaminodiphenylmethane, 2 '-diaminobiphenyl, 3' -diaminobiphenyl, 2, 4-diaminophenol, 2, 5-diaminophenol, o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 2, 3-tolylenediamine, 2, 4-tolylenediamine, 2, 5-tolylenediamine, 2, 6-tolylenediamine, 3, 4-tolylenediamine, and diethyltolylenediamine.

As the amino alcohol that can be used as the active hydrogen group-containing compound (HX), there can be mentioned: monoamines having a hydroxyl group such as monoethanolamine, diethanolamine, 2-amino-2-methyl-1-propanol, tris (hydroxymethyl) aminomethane and 2-amino-2-ethyl-1, 3-propanediol; diamines having a hydroxyl group such as N- (2-hydroxypropyl) ethanolamine, and the like.

As polythiols that can be used as the active hydrogen group-containing compound (HX), there can be mentioned: methanedithiol, 1, 3-butanedithiol, 1, 4-butanedithiol, 2, 3-butanedithiol, 1, 2-benzenedithiol, 1, 3-benzenedithiol, 1, 4-benzenedithiol, 1, 10-decanedithiol, 1, 2-ethanedithiol, 1, 6-hexanedithiol, 1, 9-nonanedithiol, 1, 8-octanedithiol, 1, 5-pentanedithiol, 1, 2-propanedithiol, 1, 3-propanedithiol, toluene-3, 4-dithiol, 3, 6-dichloro-1, 2-benzenedithiol, 1, 5-naphthalenedithiol, 1, 2-benzenedimethanethiol, 1, 3-benzenedimethanethiol, 1, 4-benzenedimethanethiol, 1, 3-benzenedithiol, 1, 4-benzenedimethanethiol, 1, 2-benzenedithiol, 1, 2-benzenedimethanethiol, 1, 2,1, 2,1, and benzene dimethanethiol, 4, 4' -thiobisbenzenethiol, 2, 5-dimercapto-1, 3, 4-thiadiazole, 1, 8-dimercapto-3, 6-dioxaoctane, 1, 5-dimercapto-3-thiopentane, 2-di-n-butylamino-4, 6-dimercapto-s-triazine, and thiol group-terminated polymers (polythioether polymers and the like).

The one or more active hydrogen group-containing compounds (HX) may comprise a difunctional active hydrogen group-containing compound and/or a trifunctional or more active hydrogen group-containing compound. In general, the bifunctional active hydrogen group-containing compound has two-dimensional crosslinkability and can impart appropriate flexibility to the adhesive layer. The trifunctional or higher active hydrogen group-containing compound has three-dimensional crosslinkability and can impart an appropriate hardness to the adhesive layer. The properties of the urethane adhesive such as adhesive force, cohesive force, and removability can be adjusted by selecting the number of functional groups (the number of active hydrogen groups) of each active hydrogen group-containing compound (HX). The number of functional groups of each material may be selected so that the properties such as adhesive force, cohesive force, and removability fall within preferable ranges according to the application.

The one or more active hydrogen group-containing compounds (HX) are preferably a di-functional active hydrogen group-containing compound and a tri-functional active hydrogen group-containing compound, in terms of easily achieving both the adhesion and removability.

The number average molecular weight (Mn) of each functional group of the active hydrogen group-containing compound (HX) is not particularly limited. In terms of the adhesive force and wettability of the adhesive layer becoming preferable, the one or more active hydrogen group-containing compounds (HX) are preferably compounds containing the following active hydrogen groups: mn is preferably 500 or more, more preferably 1000 or more, particularly preferably 2000 or more, and most preferably 3000 or more.

The active hydrogen group contained in the active hydrogen group-containing compound (HX) is preferably a hydroxyl group. That is, the active hydrogen group-containing compound (HX) is preferably a polyol.

When the active hydrogen group-containing compound (HX) is an amine compound, the interaction between the polar adherend and the hydroxyl-terminated Urethane Prepolymer (UPH) increases and the adhesive strength of the adhesive layer increases, and particularly in a (moist) hot environment, there is a concern that the adherend may be contaminated after being peeled off again. When a polyol is used as the active hydrogen group-containing compound (HX), the interaction between the polar adherend and the hydroxyl-terminated Urethane Prepolymer (UPH) is small, and the adherend can be prevented from being contaminated after being peeled off again. From the viewpoint of pot life and initial hardenability, the active hydrogen group-containing compound (HX) preferably contains a primary terminal hydroxyl group.

< polyisocyanate (N) >

As the polyisocyanate (N), known polyisocyanates can be used, and there can be mentioned: aromatic polyisocyanate, aliphatic polyisocyanate, alicyclic polyisocyanate, and the like.

Examples of the aromatic polyisocyanate include: 1, 3-phenylene diisocyanate, 4 '-diphenyl diisocyanate, 1, 4-phenylene diisocyanate, 4' -diphenylmethane diisocyanate, 2, 4-tolylene diisocyanate, 2, 6-tolylene diisocyanate, 4 '-toluidine diisocyanate, 2, 4, 6-triisocyanate toluene, 1, 3, 5-triisocyanate benzene, dianisidine diisocyanate, 4' -diphenyl ether diisocyanate and 4, 4 '-triphenylmethane triisocyanate, omega' -diisocyanate-1, 3-dimethylbenzene, omega '-diisocyanate-1, 4-dimethylbenzene, omega' -diisocyanate-1, 4-diethylbenzene, 1, 4-tetramethylxylene diisocyanate, 1, 3-tetramethylxylene diisocyanate, and the like.

Examples of the aliphatic polyisocyanate include: trimethylene diisocyanate, tetramethylene diisocyanate, Hexamethylene Diisocyanate (HDI), pentamethylene diisocyanate, 1, 2-propylene diisocyanate, 2, 3-butylene diisocyanate, 1, 3-butylene diisocyanate, dodecamethylene diisocyanate, and 2, 4, 4-trimethylhexamethylene diisocyanate, and the like.

Examples of the alicyclic polyisocyanate include: isophorone diisocyanate (IPDI), 1, 3-cyclopentane diisocyanate, 1, 3-cyclohexane diisocyanate, 1, 4-cyclohexane diisocyanate, methyl-2, 6-cyclohexane diisocyanate, 4' -methylenebis (cyclohexyl isocyanate), 1, 4-bis (isocyanatomethyl) cyclohexane, and the like.

In addition, as the polyisocyanate, there may be mentioned: trimethylolpropane adduct, biuret (biuret) form, allophanate form and trimer form (the trimer form contains an isocyanurate ring) of the polyisocyanate.

The polyisocyanate (N) is preferably an aliphatic polyisocyanate or an alicyclic polyisocyanate, more preferably Hexamethylene Diisocyanate (HDI), isophorone diisocyanate (IPDI), or the like, from the viewpoint of reducing the adhesive force in the initial stage (before the lapse of time) and after the lapse of time (particularly after the lapse of (wet) heat).

The preferred raw material compounding ratio of the hydroxyl-terminated Urethane Prepolymer (UPH) is as follows.

The raw material compounding ratio is preferably determined so that the ratio (NCO/H ratio) of the number of moles of isocyanate groups (NCO) contained in the polyisocyanate (N) to the total number of moles of active hydrogen groups (H) contained in the plurality of active hydrogen group-containing compounds (HX) is 0.20 to 0.95, more preferably 0.40 to 0.80. The closer the NCO/H ratio is to 1, the more likely it is that the hydroxyl-terminated Urethane Prepolymer (UPH) is gelled during synthesis. When the NCO/H ratio is 0.95 or less, gelation at the time of synthesis of a hydroxyl-terminated Urethane Prepolymer (UPH) can be effectively suppressed.

< catalyst >

If desired, more than one catalyst may be used in the polymerization of the hydroxyl-terminated Urethane Prepolymer (UPH). As the catalyst, a known catalyst can be used, and examples thereof include tertiary amine compounds, organometallic compounds, and the like.

Examples of the tertiary amine compound include triethylamine, triethylenediamine, and 1, 8-Diazabicyclo (5, 4, 0) -undecene-7 (1, 8-Diazabicyclo (5.4.0) -undecene-7, DBU).

Examples of the organometallic compound include tin compounds and non-tin compounds.

Examples of the tin-based compound include: dibutyl tin dichloride, dibutyl tin oxide, dibutyl tin dibromide, dibutyl tin dimaleate, dibutyl tin dilaurate, dibutyl tin diacetate, dioctyl tin dilaurate, dibutyl tin sulfide, tributyl tin oxide, tributyl tin acetate, triethyl tin ethoxide, tributyl tin ethoxide, dioctyl tin oxide, tributyl tin chloride, tributyl tin trichloroacetate, and tin 2-ethylhexanoate, and the like.

Examples of the non-tin compound include: titanium systems such as dibutyltitanium dichloride, tetrabutyl titanate, and butoxytitanium trichloride; lead-based materials such as lead oleate, lead 2-ethylhexoate, lead benzoate, and lead naphthenate; iron series such as iron 2-ethylhexanoate and iron acetylacetonate; cobalt systems such as cobalt benzoate and cobalt 2-ethylhexanoate; zinc systems such as zinc naphthenate and zinc 2-ethylhexanoate; zirconium-based compounds such as zirconium naphthenate.

The kind and amount of the catalyst may be suitably designed within a range in which the reaction proceeds well.

When a plurality of active hydrogen group-containing compounds (HX) having different reactivities are used in combination, there is a possibility that a polymerization stability defect or a reaction solution turbidity tends to occur in a single catalyst system due to the difference in reactivity. In such a case, the use of two or more catalysts makes it easy to control the reaction (for example, reaction rate), and thus the above-mentioned problems can be solved. In the system using a plurality of active hydrogen group-containing compounds (HX) having different reactivities in combination, it is preferable to use two or more catalysts. The combination of two or more catalysts is not particularly limited, and examples thereof include tertiary amine/organic metal-based, tin-based/non-tin-based, and tin-based/tin-based catalysts. Tin-based/tin-based is preferred, and dioctyl tin dilaurate and tin 2-ethylhexanoate are more preferred.

The mass ratio of tin 2-ethylhexanoate to tin dioctyldilaurate (tin 2-ethylhexanoate/tin dioctyldilaurate) is not particularly limited, but is preferably greater than 0 and less than 1, and more preferably 0.2 to 0.8. When the mass ratio is less than 1, the balance of the catalyst activity is good, gelation and clouding of the reaction solution can be effectively suppressed, and the polymerization stability is further improved.

The amount of the one or more catalysts used is not particularly limited, but is preferably 0.01 to 1.0% by mass based on the total amount of the one or more active hydrogen group-containing compounds (HX) and the one or more polyisocyanates (N).

< solvent >

If necessary, one or more solvents may be used for the polymerization of the hydroxyl-terminated Urethane Prepolymer (UPH). As the solvent, known solvents can be used, and examples thereof include: methyl ethyl ketone, ethyl acetate, toluene, xylene, acetone, and the like. In terms of solubility of the hydroxyl-terminated Urethane Prepolymer (UPH), boiling point of the solvent, and the like, ethyl acetate, toluene, and the like are particularly preferable.

< method for polymerizing hydroxyl-terminated Urethane Prepolymer (UPH) >

The polymerization method of the hydroxyl-terminated Urethane Prepolymer (UPH) is not particularly limited, and known polymerization methods such as bulk polymerization and solution polymerization can be used.

Examples of the polymerization order of the hydroxyl-terminated Urethane Prepolymer (UPH) include:

sequence 1) a sequence of putting one or more active hydrogen group-containing compounds (HX), one or more polyisocyanates (N), optionally one or more catalysts, and optionally one or more solvents into a flask together;

sequence 2) a sequence of adding one or more active hydrogen group-containing compounds (HX), optionally one or more catalysts, and optionally one or more solvents to a flask, and adding one or more polyisocyanates (N) dropwise thereto.

In the case of using a plurality of active hydrogen group-containing compounds (HX) and/or polyisocyanates (N), the reaction may be carried out in a plurality of stages.

The reaction temperature when the catalyst is used is preferably less than 100 ℃, more preferably from 50 ℃ to 95 ℃, and particularly preferably from 60 ℃ to 85 ℃. When the reaction temperature is 100 ℃ or higher, it is difficult to control the reaction rate, polymerization stability, and the like, and it is difficult to produce a hydroxyl-terminated Urethane Prepolymer (UPH) having a desired molecular weight. The reaction temperature when no catalyst is used is preferably 100 ℃ or higher, more preferably 110 ℃ or higher.

(polyfunctional isocyanate Compound (I))

As the polyfunctional isocyanate compound (I), known polyfunctional isocyanate compounds can be used, and compounds exemplified by polyisocyanate (N) which is a raw material of the hydroxyl-terminated Urethane Prepolymer (UPH) (specifically, aromatic polyisocyanate, aliphatic polyisocyanate, aromatic aliphatic polyisocyanate, alicyclic polyisocyanate, and trimethylolpropane adduct/biuret/allophanate/trimer thereof) can be used.

(surfactant (S) having cationic hydrophilic group)

The adhesive of the present invention comprises one or more surfactants (S) having a cationic hydrophilic group as follows: the amine value is 0.1mgKOH/g to 160mgKOH/g, preferably 0.1mgKOH/g to 150mgKOH/g, in terms of nonvolatile components.

The surfactant (S) may be one or two or more known cationic surfactants and/or amphoteric surfactants, and is not particularly limited as long as the amine value is 0.1mgKOH/g to 160mgKOH/g in terms of nonvolatile components. Examples of the cationic hydrophilic group include a primary to tertiary amino group, a primary to tertiary amine salt group, and a quaternary ammonium salt group.

Further, even if the structure or composition of a commercially available surfactant is not clear, the surfactant (S) may be selected so that the amine value is 0.1mgKOH/g to 160mgKOH/g, preferably 0.1mgKOH/g to 150mgKOH/g, in terms of nonvolatile matter. It is also possible to include a plurality of different cationic hydrophilic groups in one of the commercially available surfactants having the amine number.

Specific examples of commercially available cationic surfactants or amphoteric surfactants that can be used as the surfactant (S) include:

souna Pass (Solsperse)9000, Solonas Pass (Solsperse)11200, Solonas (Solsperse)13240, Solonas (Solsperse)13940, Solonas (Solsperse)16000, Solonas (Solsperse)17000, Solonas (Solsperse)18000, Solonas (Solsperse)20000, Souna Pass (Solsperse)24000, Souna Pase (Solsperse)24000GR, Souna Pase (Solsperse)26000, Souna Pase (Solsperse)28000, Souna Pase (Solonas) 3100, Solonas (Solsperse)32000, Solonas (Solsperse)56000, Solonas (Solospe) 35500, Solonas (Solospe) 3200, Solonas (Solospe) 3500, Solonas (Solonas) 3500, Solonas (Solonas) 3295, Solonas (Solonas) 3200, Solonas (Solonas) 35500, Solonas) (Solonas) 3200, Solonas) (Solonas) 3295, Solonas) (Solonas) 3200, Solonas) (Solonas) 3200, Solonas (Solonas) 3200, Solonas) (Solonas) 3295, Solonas) 3200, Solonas) (Solonas) 3200, Solonas) (Solonas) 3200, Solonas) (Solonas) 3200, Solonas) (Solonas) 3200, Solonas) (Solonas) 3295, Solonas) (Solonas) 3200, Solonas) (, Sonopause (Solsperse) D510, Sonopause (Solsperse) D530, Sonopause (Solsperse) L300, Sonopause (Solsperse) K200, Sonopause (Solsperse) K210, Sonopause (Solsperse) K500, Sonopause (Solsperse) R700;

flowen (Flowen) DOPA-15B, Flowen (Flowen) DOPA-15BHFS, Flowen (Flowen) DOPA-17HF, Flowen (Flowen) DOPA-22, Flowen (Flowen) DOPA-35, Flowen (Flowen) G-600, Flowen (Flowen) G-820, Flowen (Flowen) NC-500, Flowen (Flowen) KDG-2400 manufactured by Kyoho;

henaoarket (Hinoact) KF-1300M, Henaoactette (Hinoact) KF-1500, Henaoactette (Hinoact) KF-1700, Henaoactette (Hinoact) T-6000, Henaoactette (Hinoact) T-8000E, Henaoactette (Hinoact) T-9100, Henaoactette (Hinoact) A-110, Henaoactette (Hinoact) NB manufactured by Chuanjian refining (Fine Chemical);

dikadsnapus (TEGO Dispers)650, dikadsnapus (TEGO Dispers)660C, dikadsnapus (TEGO Dispers)662C, dikadsnapus (TEGO Dispers)670, dikadsnapus (TEGO Dispers)685, dikadsnapus (TEGO Dispers)700, dikadsnapus (TEGO Dispers)710, dikadsnapus (TEGO Dispers)760W manufactured by winkao (Evonik);

ajispar (Ajisper) PB821, Ajisper (Ajisper) PB822, Ajisper (Ajisper) PB824, Ajisper (Ajisper) PB881, and Ipomonet Fine-Techno manufactured by Ajinomoto technology,

DISPERBYK-106, DISPERBYK-108, DISPERBYK-140, DISPERBYK-142, DISPERBYK-145, DISPERBYK-161, DISPERBYK-162, DISPERBYK-163, DISPERBYK-164, DISPERBYK-167, DISPERBYK-168, DISPERBYK (DISPERBYK) -2001, DISPERBYK-182, disperbyyk-184, DISPERBYK-185, peerbyk-2008, peybyk-2000, perbyk-2009, DISPERBYK-185, perbyk-2008, diserbyk-2000, diserbyk-180, diserbyk-185, diserbyk-2008, diserbyk-180, diserbyk, disyby, diserbyk, disybyk, disyby, diserbyk, disybyk, disyby, diserbyk, disybyk, disyby, disdyy, disdyb, disyby, disdyy, disdyb, and so, disdyb, dis, Dipper (DISPERBYK) -2013, Dipper (DISPERBYK) -2022, Dipper (DISPERBYK) -2025, Dipper (DISPERBYK) -2026, Dipper (DISPERBYK) -2050, Dipper (DISPERBYK) -2055, Dipper (DISPERBYK) -2150, Dipper (DISPERBYK) -2155, Dipper (DISPERBYK) -2163, Dipper (DISPERBYK) -2164, pigment dispersants such as bisk-9076, bisk-9077, orange-orange (ANTI-tera) -U/U100, orange-orange (ANTI-tera) -204, orange-tera (ANTI-tera) -250, Disbacky (DISPERBYK) -187, Disbacky (DISPERBYK) -191, Disbacky (DISPERBYK) -2010, Disbacky (DISPERBYK) -2012, and Disbacky (DISPERBYK) -2061;

philono (Filalon) PA-075F, Philono (Filalon) PA-085C, Philono (Filalon) PA-107P, Eimem (esleam) AD-3172M, Eimem (esleam) AD-374M, Eimem (esleam) AD-508E, available from Nippon oil Co;

sharu (SHAROL) DC902P, Sharu (SHAROL) DC303P, manufactured by first Industrial pharmaceutical company;

and polymer surfactants such as texanol IL55, texanol L7, and texanol CP-81 manufactured by Nippon emulsifier corporation.

By adding one or more surfactants (S) having a cationic hydrophilic group to the adhesive comprising the active hydrogen group-containing compound (H) and the polyfunctional isocyanate compound (I), the adhesive force of the adhesive layer before and after the lapse of time can be reduced, and the increase in the adhesive force of the adhesive layer under (wet) thermal environment can be suppressed. As a result, even when exposed to a (wet) hot environment, the following adhesive layer can be formed: the re-peelability is good, and there is no adherend contamination in which an adhesive component remains on the surface of the adherend after re-peeling.

The mechanism is not necessarily clear, but is presumed as follows.

It is considered that the adhesive layer has a low adhesive force and improved removability even before and after the lapse of time by cutting the interfacial interaction between the adhesive layer and an adherend such as a glass substrate, an ITO/glass substrate having an ITO (indium tin oxide) film formed on the glass substrate, and an optical member, by the surfactant (S) having a cationic hydrophilic group.

When the amine value of the surfactant (S) in terms of nonvolatile components is 0.1mgKOH/g or more, the above-mentioned effects (particularly, the reduction in adhesion of the adhesive layer in a (wet) hot environment, the improvement in removability due to the same, and the reduction in contamination of the adherend) can be remarkably exhibited.

If the amine value of the surfactant (S) is too high, the interaction between the adherend and the surfactant (S) becomes too large, and therefore, the surfactant (S) may bleed out particularly in a (wet) hot environment, and the adherend may be contaminated after being peeled off again. It is considered that when the amine value is 160mgKOH/g or less, preferably 0.1mgKOH/g to 150mgKOH/g in terms of nonvolatile matter, the interaction between the adherend and the adhesive layer can be cut while suppressing the bleeding of the surfactant (S).

In terms of effectively exhibiting the above-described effects (particularly, reduction in adhesion of the adhesive layer under (wet) thermal environment, improvement in removability due to the adhesion, and reduction in adherend contamination), the amine value is preferably 0.1mgKOH/g to 150mgKOH/g, more preferably 0.1mgKOH/g to 100mgKOH/g, particularly preferably 0.1mgKOH/g to 60mgKOH/g, and most preferably 0.1mgKOH/g to 30mgKOH/g, in terms of nonvolatile components.

The acid value of the surfactant (S) is not particularly limited, and is preferably small. From the viewpoint of initial curing properties, and in particular, the reduction in adhesive force of the adhesive layer in a (wet) hot environment and the improvement in removability due to the reduction, the acid value is preferably 40mgKOH/g or less, more preferably 20mgKOH/g or less, particularly preferably 10mgKOH/g or less, and most preferably 0mgKOH/g in terms of nonvolatile components.

The amine number, acid number and nonvolatile content can be measured by the following methods.

< amine value >

In a stopcock conical flask, 1g of a sample was precisely measured, and dissolved in 100ml of a toluene/ethanol (volume ratio: toluene/ethanol: 1/1), followed by titration with a 0.1N-alcoholic hydrochloric acid solution. The amine value (unit: mgKOH/g) can be determined by the following formula.

Amine value { (5.61 × a × F)/S }/(nonvolatile content concentration/100)

In the formula, each symbol represents the following parameter.

S: the amount of sample collected (g),

a: consumption (ml) of 0.1N-alcoholic hydrochloric acid solution,

F: factor of 0.1N-alcoholic hydrochloric acid solution.

< acid value >

1g of a sample was precisely measured in a stopcock conical flask, and dissolved in 100ml of a toluene/ethanol (volume ratio: toluene/ethanol: 1/2), followed by titration with a 0.1N-alcoholic potassium hydroxide solution. The acid value (unit: mgKOH/g) can be determined by the following formula.

Acid value { (5.61 × a × F)/S }/(nonvolatile concentration/100)

In the formula, each symbol represents the following parameter.

S: the amount of sample collected (g),

a: consumption (ml) of 0.1N-alcoholic potassium hydroxide solution,

F: factor of 0.1N-alcoholic potassium hydroxide solution.

< nonvolatile fraction >

About 1g of the sample solution was weighed in a metal container, dried in an oven at 150 ℃ for 20 minutes, and the remaining components were weighed to calculate the remaining ratio and set as nonvolatile components (nonvolatile component concentration).

The weight average molecular weight (Mw) of the surfactant (S) is not particularly limited, but is preferably 500 or more, more preferably 1000 or more, and particularly preferably 2000 or more. When Mw is 500 or more, bleeding of the surfactant (S) over time (particularly after (wet) heat) is effectively suppressed, and staining of the adherend is improved.

The weight average molecular weight (Mw) of the surfactant (S) may be either a value specified in the table or an actual value.

The weight average molecular weight (Mw) can be determined by the method described in "example".

As related documents of the present invention, there are patent documents 1 to 4 listed in the section "prior art".

Patent document 1 describes an adhesive sheet (surface protective film) using a urethane adhesive containing a leveling agent (claim 7). As the leveling agent, a surfactant can be used. However, the patent document does not describe a surfactant having a cationic hydrophilic group, and does not describe or suggest the addition of a surfactant having a specific amine value of a cationic hydrophilic group and the action and effect thereof.

Patent document 2 discloses an adhesive containing: a polyurethane resin (A) having a hydroxyl group; a reactive compound (B) having a functional group reactive with a hydroxyl group; and a surfactant (C) (technical scheme 1). Examples of the surfactant (C) include: anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants (paragraph 0124).

Patent document 3 describes an adhesive sheet (surface protective film) using a urethane adhesive containing an antistatic agent (AS agent) (technical means 3, paragraph 0022). As the antistatic agent, there may be mentioned: nonionic, cationic, anionic and amphoteric surfactants (paragraph 0023).

Patent document 4 discloses an antistatic pressure-sensitive adhesive composition comprising:

a urethane urea resin (a) obtained by reacting a polyamino compound (c) with a urethane prepolymer obtained by reacting a polyol (a) having a polypropylene glycol skeleton or a polyester skeleton with a polyisocyanate (b);

an ionic compound (B) containing an anion containing a fluorine atom as a part of the constituent;

a curing agent (C); and

a silane coupling agent (D) having an alkoxysilane group (claim 1).

In the composition, an ionic compound (B) is used as an antistatic agent. In patent document 4, in comparative examples 21 and 24, alkylbis (2-hydroxyethyl) methylammonium chloride as a cationic surfactant was used as an antistatic agent.

However, patent documents 2 to 4 do not describe or suggest the addition of a surfactant having a specific amine value of a cationic hydrophilic group to a urethane adhesive and the action and effect thereof.

The symbols of the components described in patent documents 1 to 4 are those described in these documents, and are not related to the symbols used for the components of the present invention.

As the skeleton structure of the surfactant (S), there are a single type in which the number of hydrophilic groups is one and a comb type in which the number of hydrophilic groups is plural, and either one can be used. In order to effectively exhibit the above-described effects (particularly, reduction in adhesion of the adhesive layer in a (moist) hot environment, improvement in removability due to the reduction in contamination of the adherend), the single type in which the number of hydrophilic groups is one is preferable.

(plasticizer (P))

The adhesive of the present invention may further optionally contain one or more plasticizers (P) from the viewpoint of reduction of the adhesive force of the adhesive layer and improvement of wettability. The plasticizer (P) is not particularly limited, and is preferably an organic acid ester from the viewpoint of compatibility with other components and the like.

Examples of esters of mono-or polybasic acids with alcohols include: isostearyl laurate, isopropyl myristate, isocetyl myristate, octyldodecyl myristate, isostearyl palmitate, isocetyl stearate, octyldodecyl oleate, dibutyl phthalate, dioctyl phthalate, dipentyl phthalate, dibenzyl phthalate, butyl benzyl phthalate, diisodecyl adipate, diisostearyl adipate, dibutyl sebacate, diisocetyl sebacate, tributyl acetylcitrate, tributyl trimellitate, trioctyl trimellitate, trihexyl trimellitate, triolenyl trimellitate, and triisocetyl trimellitate.

Examples of esters of other acids with alcohols include: esters of unsaturated fatty acids or branched acids such as myristoleic acid, oleic acid, linoleic acid, linolenic acid, isopalmitic acid, and isostearic acid with alcohols such as ethylene glycol, propylene glycol, glycerol, trimethylolpropane, pentaerythritol, and sorbitan.

Examples of esters of mono-or polybasic acids with polyalkylene glycols include: polyethylene glycol dihexanoate, polyethylene glycol di-2-ethylhexanoate, polyethylene glycol dilaurate, polyethylene glycol dioleate, and diethylene glycol methyl ether adipate.

From the viewpoint of improving wettability, the molecular weight (formula weight or Mn) of the organic acid ester is preferably 250 to 1,000, more preferably 400 to 900, and particularly preferably 500 to 850. When the molecular weight is 250 or more, the heat resistance of the adhesive layer is good, and when the molecular weight is 1,000 or less, the wettability of the adhesive is good.

The plasticizer (P) is preferably small from the viewpoint of suppressing contamination of the adherend. The amount of the one or more plasticizers (P) is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, and particularly preferably 10 parts by mass or less, with respect to 100 parts by mass of the active hydrogen group-containing compound (H).

(solvent)

The adhesives of the invention may optionally contain more than one solvent. As the solvent, known solvents can be used, and examples thereof include: methyl ethyl ketone, ethyl acetate, toluene, xylene, acetone, and the like. From the viewpoints of solubility of the active hydrogen group-containing compound (H) and the boiling point of the solvent, ethyl acetate, toluene and the like are particularly preferable.

(anti-deterioration agent)

The adhesive of the present invention may optionally contain more than one anti-deterioration agent. This can suppress deterioration of various properties due to long-term use of the adhesive layer. As the deterioration preventing agent, there can be mentioned: hydrolysis resistance agents, antioxidants, ultraviolet absorbers, light stabilizers, and the like.

< hydrolysis resistance agent >

In the case where a carboxyl group is generated by a hydrolysis reaction in the adhesive layer under a (hot and humid) environment or the like, a hydrolysis resistant agent may be used in order to block the carboxyl group. As hydrolysis resistance agents, there can be mentioned: carbodiimide, oxazoline and epoxy systems. Among them, a carbodiimide type is preferable from the viewpoint of the hydrolysis suppressing effect.

The carbodiimide-based hydrolysis inhibitor is a compound having one or more carbodiimide groups in one molecule.

Examples of the monocarbodiimide compound include: dicyclohexylcarbodiimide, diisopropylcarbodiimide, dimethylcarbodiimide, diisobutylcarbodiimide, dioctylcarbodiimide, diphenylcarbodiimide, naphthylcarbodiimide and the like.

The polycarbodiimide compound may be produced by subjecting a diisocyanate to a decarbonylation condensation reaction in the presence of a carbodiimidization catalyst. Examples of the diisocyanate include: 4, 4 ' -diphenylmethane diisocyanate, 3 ' -dimethoxy-4, 4 ' -diphenylmethane diisocyanate, 3 ' -dimethyl-4, 4 ' -diphenylmethane diisocyanate, 4 ' -diphenylether diisocyanate, 3 ' -dimethyl-4, 4 ' -diphenylether diisocyanate, 2, 4-tolylene diisocyanate, 2, 6-tolylene diisocyanate, 1-methoxyphenyl-2, 4-diisocyanate, isophorone diisocyanate, 4 ' -dicyclohexylmethane diisocyanate, tetramethylxylene diisocyanate, and the like. Examples of the carbodiimidization catalyst include: phospholene oxides such as 1-phenyl-2-phospholene (phospholene) -1-oxide, 3-methyl-2-phospholene-1-oxide, 1-ethyl-2-phospholene-1-oxide, and 3-phospholene isomers thereof.

Examples of oxazoline hydrolysis inhibitors include: 2, 2 ' -o-phenylenebis (2-oxazoline), 2 ' -m-phenylenebis (2-oxazoline), 2 ' -p-phenylenebis (4-methyl-2-oxazoline), 2 ' -m-phenylenebis (4-methyl-2-oxazoline), 2 ' -p-phenylenebis (4, 4 ' -dimethyl-2-oxazoline), 2 ' -m-phenylenebis (4, 4 ' -dimethyl-2-oxazoline), 2 ' -ethylenebis (2-oxazoline), 2 ' -tetramethylenebis (2-oxazoline), 2 ' -hexamethylenebis (2-oxazoline), 2, 2 ' -octamethylenebis (2-oxazoline), 2 ' -ethylenebis (4-methyl-2-oxazoline), 2 ' -diphenylenebis (2-oxazoline), and the like.

Examples of the epoxy-based hydrolyzing agent include: diglycidyl ethers of aliphatic diols such as 1, 6-hexanediol, neopentyl glycol, and polyalkylene glycol; polyglycidyl ethers of aliphatic polyhydric alcohols such as sorbitol, sorbitan, polyglycerol, pentaerythritol, diglycerol, glycerol, and trimethylolpropane; polyglycidyl ethers of alicyclic polyols such as cyclohexanedimethanol; diglycidyl esters or polyglycidyl esters of aliphatic or aromatic polycarboxylic acids such as terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, trimellitic acid, adipic acid, and sebacic acid; diglycidyl ethers or polyglycidyl ethers of polyhydric phenols such as resorcinol, bis- (p-hydroxyphenyl) methane, 2, 2-bis- (p-hydroxyphenyl) propane, tris- (p-hydroxyphenyl) methane and 1, 1, 2, 2-tetrakis (p-hydroxyphenyl) ethane; n-glycidyl derivatives of amines such as N, N-diglycidylaniline, N-diglycidyltoluidine, and N, N' -tetraglycidyl-bis- (p-aminophenyl) methane; triglycidyl derivatives of aminophenols; triglycidyl tris (2-hydroxyethyl) isocyanurate and triglycidyl isocyanurate; epoxy resins such as o-cresol type epoxy resins and phenol novolac type epoxy resins.

The addition amount of the hydrolysis resistant agent is not particularly limited, and is preferably 0.1 to 5 parts by mass, more preferably 0.2 to 4.5 parts by mass, and particularly preferably 0.5 to 3 parts by mass, based on 100 parts by mass of the active hydrogen group-containing compound (H).

< antioxidant >

Examples of the antioxidant include a radical scavenger and a peroxide decomposer. Examples of the radical scavenger include phenol compounds and amine compounds. Examples of the peroxide decomposer include sulfur compounds and phosphorus compounds.

Examples of the phenolic compound include: 2, 6-di-tert-butyl-p-cresol, butylated hydroxyanisole, 2, 6-di-tert-butyl-4-ethylphenol, stearyl β - (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate, 2 '-methylenebis (4-methyl-6-tert-butylphenol), 2' -methylenebis (4-ethyl-6-tert-butylphenol), 4 '-thiobis (3-methyl-6-tert-butylphenol), 4' -butylidenebis (3-methyl-6-tert-butylphenol), 3, 9-bis [1, 1-dimethyl-2- [ β - (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy ] ethyl ]2, 4, 8, 10-tetraoxaspiro [5, 5] undecane, phenylpropionic acid, 3, 5-bis (1, 1-dimethylethyl) -4-hydroxy-, C7-C9 side chain alkyl ester, 1, 3-tris (2-methyl-4-hydroxy-5-t-butylphenyl) butane, 1, 3, 5-trimethyl-2, 4, 6-tris (3, 5-di-t-butyl-4-hydroxybenzyl) benzene, tetrakis- [ methylene-3- (3 ', 5' -di-t-butyl-4 '-hydroxyphenyl) propionate ] methane, ethylene glycol bis [3, 3' -bis- (4 '-hydroxy-3' -t-butylphenyl) butyrate ], 1, 3, 5-tris (3 ', 5 ' -di-tert-butyl-4 ' -hydroxybenzyl) -S-triazine-2, 4, 6- (1H, 3H, 5H) trione, tocopherol, and the like.

Examples of the sulfur-based antioxidant include: dilauryl 3, 3 ' -thiodipropionate, dimyristyl 3, 3 ' -thiodipropionate, distearyl 3, 3 ' -thiodipropionate, and the like.

Examples of the phosphorus-based compound include: triphenyl phosphite, diphenylisodecyl phosphite, 4' -butylidene-bis- (3-methyl-6-tert-butylphenyl-ditridecyl) phosphite, cyclopentanetetraylbis (octadecyl phosphite), tris (nonylphenyl) phosphite, tris (monononylphenyl) phosphite, tris (dinonylphenyl) phosphite, diisodecyl pentaerythritol diphosphite, 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10- (3, 5-di-tert-butyl-4-hydroxybenzyl) -9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-decyloxy-9, 10-dihydro-9-oxa-10-phosphaphenanthrene, tris (2, 4-di-tert-butylphenyl) phosphite, cycloneopentanetetraylbis (2, 6-di-tert-butyl-4-methylphenyl) phosphite, and 2, 2-methylenebis (4, 6-di-tert-butylphenyl) octylphosphite.

By using the antioxidant, thermal deterioration of the active hydrogen group-containing compound (H) can be prevented.

The amount of the antioxidant to be added is not particularly limited, but is preferably 0.01 to 5 parts by mass, more preferably 0.1 to 3 parts by mass, and particularly preferably 0.2 to 2 parts by mass, based on 100 parts by mass of the active hydrogen group-containing compound (H).

As the antioxidant, from the viewpoint of stability and antioxidant effect, it is preferable to use one or more phenolic compounds as the radical scavenger, and more preferable to use one or more phenolic compounds as the radical scavenger in combination with one or more phosphorus compounds as the peroxide decomposer. In addition, it is particularly preferable to use a phenol compound as a radical scavenger and a phosphorus compound as a peroxide decomposer in combination as the antioxidant, and to use these antioxidants and the hydrolysis resistance agent in combination.

< ultraviolet absorber >

Examples of the ultraviolet absorber include: benzophenone-based compounds, benzotriazole-based compounds, salicylic acid-based compounds, oxalic acid aniline-based compounds, cyanoacrylate-based compounds, triazine-based compounds, and the like.

The amount of the ultraviolet absorber added is not particularly limited, but is preferably 0.01 to 3 parts by mass, more preferably 0.1 to 2.5 parts by mass, and particularly preferably 0.2 to 2 parts by mass, based on 100 parts by mass of the active hydrogen group-containing compound (H).

< light stabilizer >

Examples of the light stabilizer include hindered amine compounds and hindered piperidine compounds. The amount of the light stabilizer to be added is not particularly limited, but is preferably 0.01 to 2 parts by mass, more preferably 0.1 to 1.5 parts by mass, and particularly preferably 0.2 to 1 part by mass, based on 100 parts by mass of the active hydrogen group-containing compound (H).

(antistatic agent (AS agent))

The adhesive of the present invention may optionally contain one or more antistatic agents (AS agents) (except the active hydrogen group-containing compound (H) and the surfactant (S)). Examples of the antistatic agent include inorganic salts, ionic liquids, ionic solids, and surfactants, and among them, ionic liquids and ionic solids are preferable. The "ionic liquid" may be also referred to as an ambient temperature molten salt, and is a salt having fluidity at 25 ℃.

Examples of the inorganic salt include: sodium chloride, potassium chloride, lithium perchlorate, ammonium chloride, potassium chlorate, aluminum chloride, copper chloride, ferrous chloride, ferric chloride, ammonium sulfate, potassium nitrate, sodium carbonate, sodium thiocyanate and the like.

Examples of the ionic liquid containing an imidazolium ion include: 1-ethyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide, 1, 3-dimethylimidazolium bis (trifluoromethylsulfonyl) imide, and 1-butyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide.

Examples of the ionic liquid containing a pyridinium ion include: 1-methylpyridinium bis (trifluoromethylsulfonyl) imide, 1-butylpyridinium bis (trifluoromethylsulfonyl) imide, 1-hexylpyridinium bis (trifluoromethylsulfonyl) imide, 1-octylpyridinium bis (trifluoromethylsulfonyl) imide, 1-hexyl-4-methylpyridinium bis (trifluoromethylsulfonyl) imide, 1-hexyl-4-methylpyridinium hexafluorophosphate, 1-octyl-4-methylpyridinium bis (trifluoromethylsulfonyl) imide, 1-octyl-4-methylpyridinium bis (fluorosulfonyl) imide, 1-methylpyridinium bis (perfluoroethylsulfonyl) imide, and 1-methylpyridinium bis (perfluorobutylsulfonyl) imide, and the like.

Examples of the ionic liquid containing an ammonium ion include: 1-butyl-3-methylpyridinium bis (trifluoromethanesulfonyl) imide, trimethylpentylammonium bis (trifluoromethanesulfonyl) imide, N-diethyl-N-methyl-N-propylammonium bis (trifluoromethanesulfonyl) imide, N-diethyl-N-methyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide, tri-N-butylmethylammonium bis (trifluoromethanesulfonyl) imide, and the like.

In addition, commercially available ionic liquids such as pyrrolizium salts, phosphonium salts, sulfonium salts and the like can be suitably used.

The ionic solid is a salt of a cation and an anion, as in the case of an ionic liquid, and shows a solid state at 25 ℃ under normal pressure. Examples of the cation include alkali metal ions, phosphonium ions, pyridinium ions, and ammonium ions.

Examples of the ionic solid containing an alkali metal ion include: lithium bis-fluorosulfonyl imide, lithium bis-trifluoromethylsulfonyl imide, lithium bis-pentafluoroethylsulfonyl imide, lithium bis-heptafluoropropylsulfonyl imide, lithium bis-nonafluorobutylsulfonyl imide, sodium bis-fluorosulfonyl imide, sodium bis-trifluoromethylsulfonyl imide, sodium bis-pentafluoroethylsulfonyl imide, sodium bis-heptafluoropropylsulfonyl imide, sodium bis-nonafluorobutylsulfonyl imide, potassium bis-fluorosulfonyl imide, potassium bis-trifluoromethylsulfonyl imide, potassium bis-pentafluoroethylsulfonyl imide, potassium bis-heptafluoropropylsulfonyl imide, and potassium bis-nonafluorobutylsulfonyl imide.

Examples of ionic solids containing phosphonium ions include: tetrabutylphosphonium bis (fluorosulfonyl imide), tetrabutylphosphonium bis (trifluoromethylsulfonyl imide), tetrabutylphosphonium bis (pentafluoroethylsulfonyl imide), tetrabutylphosphonium bis (heptafluoropropylsulfonyl imide), tetrabutylphosphonium bis (nonylfluorobutylsulfonyl imide), tributylhexadecylphosphonium bis (fluorosulfonyl imide), tributylhexadecylphosphonium bis (trifluoromethylsulfonyl imide), tributylhexadecylphosphonium bis (pentafluoroethylsulfonyl imide), tributylhexadecylphosphonium bis (heptafluoropropylsulfonyl imide), tributylhexadecylphosphonium bis (nonylfluorobutylsulfonyl imide, tetraoctylphosphonium bis (fluorosulfonyl imide), tetraoctylphosphonium bis (trifluoromethylsulfonyl imide), tetraoctylphosphonium bis (pentafluoroethylsulfonyl imide), tetraoctylphosphonium bis (heptafluoropropylsulfonyl imide, tetraoctylphosphonium bis (nonylfluorobutylsulfonyl imide), and the like.

Examples of the ionic solid containing a pyridinium ion include: 1-hexadecyl-4-methylpyridinium difluorosulfonimide, 1-hexadecyl-4-methylpyridinium bistrifluoromethylsulfonimide, 1-hexadecyl-4-methylpyridinium dipentafluoroethylsulfonyl imide, 1-hexadecyl-4-methylpyridinium bistetrafluoropropylsulfonimide, and 1-hexadecyl-4-methylpyridinium dinonylfluorobutylsulfonimide, etc.

Examples of the ionic solid containing an ammonium ion include: lauryl trimethyl ammonium chloride, tributylmethyl bis (trifluoromethyl) sulfonyl imide, tributylmethyl bis (pentafluoroethyl) sulfonyl imide, tributylmethyl bis (heptafluoropropyl) sulfonyl imide, tributylmethyl bis (nonane) fluorobutyl sulfonyl imide, octyltributyl bis (trifluoromethyl) sulfonyl imide, octyltributyl bis (pentafluoroethyl) sulfonyl imide, octyltributyl bis (heptafluoropropyl) sulfonyl imide, octyltributyl bis (nonane) fluorobutyl sulfonyl imide, tetrabutyl bis (fluoro) sulfonyl imide, tetrabutyl bis (trifluoromethyl) sulfonyl imide, tetrabutyl bis (pentafluoroethyl) sulfonyl imide, tetrabutyl bis (heptafluoropropyl) sulfonyl imide, tetrabutyl bis (nonane) fluorobutyl sulfonyl imide, and the like.

In addition, as the cation, a known ionic solid such as a pyrrolizium ion, an imidazolium ion, and a sulfonium ion can be suitably used.

Surfactants other than the surfactant (S) include nonionic surfactants and anionic surfactants, and any of the types is classified into low-molecular surfactants and high-molecular surfactants.

Examples of the nonionic low-molecular-weight surfactant include: glycerin fatty acid ester, polyoxyalkylene alkyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene alkylamine fatty acid ester, fatty acid diethanolamide, and the like.

Examples of the anionic low-molecular-weight surfactant include: alkyl sulfonates, alkylbenzene sulfonates, and alkyl phosphate esters.

Examples of the amphoteric low-molecular-weight surfactant include alkyl betaines and alkyl imidazolium betaines.

Examples of the nonionic polymer surfactant include: polyether ester amide type, ethylene oxide-epichlorohydrin type, polyether ester type, and the like.

Examples of the anionic polymeric surfactant include polystyrene sulfonic acid type surfactants.

Examples of the amphoteric polymer surfactant include: and amino acid type amphoteric surfactants such as higher alkyl aminopropionates, and betaine type amphoteric surfactants such as higher alkyl dimethyl betaines and higher alkyl dihydroxyethyl betaines.

The amount of the antistatic agent (AS agent) added is preferably 0.01 to 10 parts by mass, more preferably 0.03 to 5 parts by mass, based on 100 parts by mass of the active hydrogen group-containing compound (H).

(leveling agent)

The adhesive of the present invention may optionally contain a leveling agent. By adding the leveling agent, the leveling property of the adhesive layer can be improved. As the leveling agent, there can be mentioned: acrylic leveling agents, fluorine leveling agents, silicone leveling agents, and the like are preferred from the viewpoint of suppressing contamination of the adherend after re-peeling of the adhesive sheet.

The amount of the leveling agent is not particularly limited, and is preferably 0.001 to 2 parts by mass, more preferably 0.01 to 1.5 parts by mass, and particularly preferably 0.1 to 1 part by mass, based on 100 parts by mass of the active hydrogen group-containing compound (H), from the viewpoint of suppressing contamination of an adherend after the adhesive sheet is peeled off again and improving the leveling property of the adhesive layer.

(other optional ingredients)

The adhesive of the present invention may contain other optional components as necessary within a range not impairing the effects of the present invention. As other optional components, there may be mentioned: a catalyst, a resin other than the urethane resin, a filler (talc, calcium carbonate, titanium oxide, or the like), a metal powder, a colorant (pigment, or the like), a foil, a softening agent, a conductive agent, a silane coupling agent, a lubricant, an anticorrosive agent, a heat-resistant stabilizer, a weather-resistant stabilizer, a polymerization inhibitor, an antifoaming agent, or the like.

When the adhesive of the present invention contains a catalyst, it is preferable to add a known catalyst action inhibitor such as acetylacetone for the purpose of increasing the pot life of the adhesive.

(mixing ratio)

The adhesive of the present invention contains one or more active hydrogen group-containing compounds (H) (preferably, hydroxyl-terminated Urethane Prepolymers (UPH)), one or more polyfunctional isocyanate compounds (I), and a surfactant (S) having a cationic hydrophilic group as essential components, and further contains one or more optional components as required. The blending ratio of these is not particularly limited, and preferred blending ratios are as follows.

The amount of the one or more polyfunctional isocyanate compounds (I) is preferably 1 to 30 parts by mass, more preferably 3 to 20 parts by mass, relative to 100 parts by mass of the one or more active hydrogen group-containing compounds (H). When the amount of the one or more polyfunctional isocyanate compounds (I) is 1 part by mass or more, the cohesive force of the adhesive layer becomes good, and when it is 30 parts by mass or less, the pot life becomes good.

In terms of effectively exhibiting the above-described effects (particularly, low adhesion of the adhesive layer in a (wet) hot environment, improvement of removability due to the low adhesion, and reduction of adherend contamination), the amount of the one or more surfactants (S) is 0.01 to 20 parts by mass, preferably 0.1 to 10 parts by mass, and more preferably 0.2 to 5.0 parts by mass, based on 100 parts by mass of the one or more active hydrogen group-containing compounds (H).

If the amount of the surfactant (S) added is too small, the effect of the addition may not be effectively exhibited. If the amount of the surfactant (S) added is too large, the adherend may be contaminated by bleeding of the surfactant (S) when exposed to a (moist) hot environment.

(method for producing adhesive)

The method for producing the adhesive of the present invention is not particularly limited.

The adhesive of the present invention can be produced by adding and mixing one or more polyfunctional isocyanate compounds (I), one or more surfactants (S) and optionally one or more optional components to one or more active hydrogen group-containing compounds (H) (preferably, hydroxyl-terminated Urethane Prepolymers (UPH) synthesized by the above-described method).

The gel fraction of the adhesive after curing is preferably 70% or more, more preferably 80% or more, particularly preferably 90% or more, and most preferably 95% or more. When the gel fraction is 70% or more, the cohesive strength of the adhesive layer becomes good, and good adhesive strength and removability can be obtained even after exposure to (moist) heat environment, and contamination of the adherend can be reduced by reduction of exudation components. The gel fraction can be determined by the method described in "example".

[ adhesive sheet ]

The adhesive sheet of the present invention comprises: a substrate sheet, and an adhesive layer containing a cured product of the adhesive of the present invention. The adhesive layer may be formed on one or both sides of the substrate sheet. If necessary, the exposed surface of the adhesive layer may be covered with a release sheet. Further, the release sheet is peeled off when the adhesive sheet is attached to an adherend.

Fig. 1 is a schematic cross-sectional view of an adhesive sheet according to a first embodiment of the present invention. In fig. 1, reference numeral 10 denotes an adhesive sheet, reference numeral 11 denotes a base sheet, reference numeral 12 denotes an adhesive layer, and reference numeral 13 denotes a release sheet. The adhesive sheet 10 is a single-sided adhesive sheet having an adhesive layer formed on one side of a base sheet.

Fig. 2 is a schematic cross-sectional view of an adhesive sheet according to a second embodiment of the present invention. In fig. 2, reference numeral 20 denotes an adhesive sheet, reference numeral 21 denotes a base sheet,

reference numerals

22A and 22B denote adhesive layers, and

reference numerals

23A and 23B denote release sheets.

The substrate sheet is not particularly limited, and examples thereof include a resin sheet, paper, and a metal foil. The base sheet may be a laminate sheet in which any one or more layers are laminated on at least one surface of the base sheets. The surface of the substrate sheet on the side where the adhesive layer is formed may be subjected to an easy adhesion treatment such as corona discharge treatment and anchor coating agent application, if necessary.

The resin constituting the resin sheet is not particularly limited, and includes: ester resins such as polyethylene terephthalate (PET); olefin resins such as Polyethylene (PE) and polypropylene (PP); vinyl resins such as polyvinyl chloride; amide resins such as nylon 66; urethane resin (including foam); combinations of these, and the like.

The thickness of the resin sheet other than the polyurethane (polyurethane) sheet is not particularly limited, and is preferably 15 to 300 μm. The thickness of the polyurethane sheet (including the foam) is not particularly limited, and is preferably 20 μm to 50,000 μm.

The paper is not particularly limited, and may be plain paper, coated paper, and coated paper.

The constituent metal of the metal foil is not particularly limited, and aluminum, copper, a combination thereof, and the like can be mentioned.

The release sheet is not particularly limited, and a known release sheet obtained by applying a known release treatment such as coating with a release agent to the surface of a substrate sheet such as a resin sheet or paper can be used.

The adhesive sheet can be produced by a known method.

First, the adhesive of the present invention is applied to the surface of a substrate sheet to form a coating layer containing the adhesive of the present invention. As the coating method, a known method can be used, and examples thereof include a roll coater (roll coater) method, a comma coater (comma coater) method, a die coater (die coater) method, a reverse coater (reverse coater) method, a silk screen printing (silk screen) method, and a gravure coater (gravure coater) method.

Next, the coating layer is dried and cured to form an adhesive layer containing a cured product of the adhesive of the present invention. The heating and drying temperature is not particularly limited, but is preferably about 60 ℃ to 150 ℃. The thickness of the adhesive layer (thickness after drying) varies depending on the application, but is preferably 0.1 to 200 μm.

Next, a release sheet is attached to the exposed surface of the adhesive layer by a known method as needed.

Thus, a single-sided adhesive sheet can be produced.

By performing the above operation on both sides, a double-sided adhesive sheet can be manufactured.

In contrast to the above method, a coating layer containing the adhesive of the present invention is formed by applying the adhesive of the present invention to the surface of a release sheet, and then the coating layer is dried and cured to form an adhesive layer containing a cured product of the adhesive of the present invention, and a substrate sheet may be laminated on the exposed surface of the adhesive layer.

The method for producing an adhesive sheet preferably includes: a coating step of coating an adhesive on a substrate sheet; a heating step of forming an adhesive layer containing a cured product of an adhesive by heating and drying the formed coating layer; a winding step of winding the obtained adhesive sheet around a winding core to form an adhesive sheet roll; and a curing step of curing the adhesive sheet roll.

As described above, according to the present invention, it is possible to provide an adhesive which has good initial curability, reduced adhesive force even in the initial stage (before time elapses) or after time elapses (particularly after (wet) heat elapses), good removability, and can form an adhesive layer which is less contaminated with an adherend after removability, and an adhesive sheet using the same.

According to the present invention, there can be provided an adhesive which is suppressed in increase in adhesive force even when exposed to a (moist) heat environment, has good removability, and can form an adhesive layer with less contamination of an adherend after removability, and an adhesive sheet using the same.

[ use ]

The adhesive sheet of the present invention can be used in the form of a tape, a label, a sheet, a double-sided tape, or the like. The adhesive sheet of the present invention can be preferably used as a surface protective sheet, a cosmetic sheet, an anti-slip sheet, and the like.

Flat panel displays such as Liquid Crystal Displays (LCDs) and organic electroluminescent displays (OELDs), and touch panel displays in which the flat panel displays and the touch panel are combined are widely used in electronic devices such as Televisions (TVs), Personal Computers (PCs), mobile phones, and portable information terminals.

The adhesive sheet of the present invention is preferably used as a surface protective sheet for flat panel displays, touch panel displays (these are also collectively referred to simply as "displays"), substrates produced or used in these production steps (glass substrates, ITO/glass substrates having an ITO (indium tin oxide) film formed on a glass substrate, and the like), optical members, and the like.

Examples

Synthetic examples, examples of the present invention, and comparative examples are described below. In the following description, "part" means part by mass, "%" means% by mass, and "RH" means relative humidity unless otherwise specified.

[ measurement of Mn and Mw ]

The number average molecular weight (Mn) and the weight average molecular weight (Mw) were measured by a Gel Permeation Chromatography (GPC) method. The measurement conditions are as follows. Both Mn and Mw are values in terms of polystyrene.

< measurement conditions >

The device comprises the following steps: shimadzu excellence (Shimadzu project) (manufactured by Shimadzu corporation),

Pipe column: 2 LF-804 manufactured by Shodex (Shodex) were connected in series,

A detector: a differential refractive index detector (RID-10A),

Solvent: tetrahydrofuran (THF),

Flow rate: 1mL/min,

Temperature of the solvent: at 40 deg.C,

Sample concentration: 0.2 percent of,

Sample injection amount: 100 μ L.

[ Material ]

The materials used are as follows.

(active hydrogen group-containing Compound (HX))

< polyols having relatively high molecular weights and Mn of 100 or more >

(HX-11): p-1010 polyol (Kuraray), a bifunctional polyester polyol (manufactured by Kuraray Co., Ltd.), a hydroxyl group value of 112.2,

(HX-12): PEG400, a difunctional polyether polyol made by Sanyo chemical industries, a hydroxyl value of 280.5,

(HX-13): sannix (SANNIX) PP-2000, a difunctional polypropylene glycol, hydroxyl number 56.1, manufactured by Sanyo chemical industries, Ltd,

(HX-14): preminol 5001F, a difunctional polyether polyol made by Asahi glass company, a hydroxyl value of 28.1, a degree of unsaturation of 0.02, a polyol having a hydroxyl group, and a polyol having a hydroxyl group,

(HX-15): GL3000, a trifunctional polyether polyol manufactured by Sanyo chemical industries, hydroxyl value 56.1,

(HX-16): GP3000, a trifunctional polyether polyol, manufactured by Sanyo chemical industries, hydroxyl value 56.1,

(HX-17): excinol 851, manufactured by Asahi glass company, a trifunctional polyether polyol, a hydroxyl value of 25.1, and an unsaturation value of 0.04.

(HX-18): praminole (priminol) 7012, available from Asahi glass company, a trifunctional polyether polyol, a hydroxyl value of 16.8, and an unsaturation value of 0.02.

The units of unsaturation are meq/g.

< polyamine >

(HX-21): IPDA, isophoronediamine, made by Yingchu (EVONIK) Inc., a difunctional polyamine.

< amino alcohol >

(HX-22): AMP, 2-amino-2-methyl-1-propanol, difunctional amino alcohols.

< lower molecular weight polyol having Mn less than 100 >

(HX-31): 1, 3PDO, 1, 3-propanediol, difunctional polyol.

The number of functional groups of each active hydrogen group-containing compound (HX), Mn, and Mn per functional group are shown in tables 2-1 and 2-2. The number of terminal hydroxyl groups (terminal OH) for the polyol is also shown in the table.

(polyisocyanate (N))

(N-11): HDI, hexamethylene diisocyanate, Koshika polyurethane (Sumika Covestro Urethane) Co., Ltd., Desmodur (Desmodur) H,

(N-12): TDI, tolylene diisocyanate (a mixture of 2, 4-tolylene diisocyanate (80% by mass) and 2, 6-tolylene diisocyanate (20% by mass), Crohn's acid (CORONATE) T-80, available from Tosoh corporation,

(N-13): IPDI, isophorone diisocyanate, manufactured by Sumika Covestro Urethane, Inc., Desmodium Multiflorum (Desmodur) I.

The number of functional groups of each polyisocyanate (N), Mn, and Mn per functional group are shown in tables 2-1 and 2-2.

(polyfunctional isocyanate Compound (I))

(I-11) HDI adduct, Crosstide (CORONATE) HL, manufactured by Tosoh corporation, Hexamethylene Diisocyanate (HDI)/Trimethylolpropane (TMP) adduct, HDI/TMP, HDI, and TMP,

(I-12) HDI isocyanurate, Sumidur N-3300, available from Sumika Bayer Urethane corporation, Hexamethylene Diisocyanate (HDI)/isocyanurate.

(surfactant (S) having cationic hydrophilic group, other surfactant (R))

A list of the surfactant (S) having a cationic hydrophilic group and the other surfactants (R) used is shown in table 1. In the table, the amine value and the acid value are calculated as nonvolatile components (unit is mgKOH/g).

(plasticizer (P))

(P-11): exoparu (EXCEPARL) MOL, methyl oleate, a commercially available product of Kao corporation,

(P-12): mosaize (Monocizer) W262, polyether ester plasticizer, DIC company.

(antioxidant (C))

(C-11): lyocell (IRGANOX)1010, pentaerythritol tetrakis [3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ], a phenolic antioxidant, and BASF.

[ Synthesis example of a solution of a hydroxyl-terminated Urethane Prepolymer (UPH) ]

Synthesis example 1 (1-stage polymerization Process)

Into a four-necked flask equipped with a stirrer, a reflux condenser, a nitrogen gas inlet tube, a thermometer, and a dropping funnel, 5 parts by mass of an active hydrogen group-containing compound (HX-11), 95 parts by mass of an active hydrogen group-containing compound (HX-18), 1.6 parts by mass of a polyisocyanate (N-11), 67 parts by mass of toluene, 0.020 parts by mass of dioctyltin dilaurate as a catalyst, and 0.008 parts by mass of tin 2-ethylhexanoate were charged and mixed. The internal solution was slowly heated to 75 ℃ to carry out the reaction for 3 hours.

The ratio (NCO/H ratio) of the number of moles of isocyanate groups in the polyisocyanate (N) used in the reaction to the total number of moles of active hydrogen groups in all the active hydrogen group-containing compounds (HX) used in the reaction was 0.49.

After the disappearance of the remaining isocyanate group was confirmed by infrared spectroscopic analysis (IR analysis), the internal solution was cooled to 30 ℃. Finally, 0.56 part by mass of acetylacetone was added.

Thus, a colorless and transparent solution of a hydroxyl-terminated urethane prepolymer (UPH-1) having a nonvolatile content of 60% and a viscosity of 2,100cps was obtained. The Mw of the obtained hydroxyl-terminated urethane prepolymer was 105,000.

The formulation composition, NCO/H ratio, and Mw of the resulting hydroxyl-terminated urethane prepolymer are shown in Table 2-1.

Synthesis examples 2 to 12 (1-stage polymerization method)

In synthetic examples 2 to 12, colorless and transparent solutions of hydroxyl-terminated urethane prepolymer (UPH-2) to hydroxyl-terminated urethane prepolymer (UPH-11) were obtained by a 1-stage polymerization method in the same manner as in synthetic example 1, except that the kind of the active hydrogen group-containing compound (HX), the kind of the polyisocyanate (N), and the blending ratio thereof were changed.

In each synthesis example, the formulation composition, NCO/H ratio, and Mw of the obtained hydroxyl-terminated urethane prepolymer are shown in tables 2-1 and 2-2.

Synthesis example 13 (multistage polymerization method)

100 parts by mass of an active hydrogen group-containing compound (HX-13), 17 parts by mass of a polyisocyanate (N-13), 29.3 parts by mass of toluene, and 0.01 part by mass of dioctyltin dilaurate as a catalyst were put into a four-necked flask equipped with a stirrer, a reflux condenser, a nitrogen inlet, a thermometer, and a dropping funnel, and mixed. The internal solution was slowly heated to 100 ℃ to carry out the reaction for 2 hours. Thereafter, the mixture was cooled to 25 ℃ and 90.7 parts by mass of ethyl acetate and 0.5 part by mass of acetylacetone were added, and then 3.4 parts by mass of the active hydrogen group-containing compound (HX-21) was added dropwise over 1 hour. After the liquid temperature was maintained at 25 ℃ and the reaction was continued for 1 hour, 1.2 parts by mass of an active hydrogen group-containing compound (HX-22) was added and allowed to react. After the disappearance of the remaining isocyanate group was confirmed by infrared spectroscopic analysis (IR analysis), the reaction was terminated.

Thus, a colorless and transparent solution of a hydroxyl-terminated urethane prepolymer (UPH-12) having a nonvolatile content of 45% and a viscosity of 3,100cps was obtained. The Mw of the obtained hydroxyl-terminated urethane prepolymer was 52,000.

The formulation composition, NCO/H ratio and Mw of the resulting hydroxyl-terminated urethane prepolymer are shown in Table 2-2.

Synthesis example 14 (multistage polymerization method)

100 parts by mass of an active hydrogen group-containing compound (HX-18), 6.5 parts by mass of a polyisocyanate (N-13), 45.7 parts by mass of toluene, and 0.02 part by mass of dioctyltin dilaurate as a catalyst were put into a four-necked flask equipped with a stirrer, a reflux condenser, a nitrogen inlet, a thermometer, and a dropping funnel, and mixed. The internal solution was slowly heated to 80 ℃ and reacted for 2 hours to obtain an isocyanate group-terminated prepolymer. Thereafter, the reaction mixture was cooled to 60 ℃ and 26.6 parts by mass of ethyl acetate was added, followed by addition and reaction of 2.5 parts by mass of the active hydrogen group-containing compound (HX-31). After the disappearance of the remaining isocyanate group was confirmed by infrared spectroscopic analysis (IR analysis), the internal solution was cooled to 30 ℃. Finally, 0.43 part by mass of acetylacetone was added.

Thus, a colorless and transparent solution of a hydroxyl-terminated urethane prepolymer (UPH-13) having a nonvolatile content of 60% and a viscosity of 2,800cps was obtained. The Mw of the obtained hydroxyl-terminated urethane prepolymer was 98,000.

[ production of urethane adhesive and adhesive sheet ]

(example 1)

A urethane adhesive was obtained by mixing 100 parts by mass (calculated as nonvolatile matter) of the solution of the hydroxyl-terminated urethane prepolymer (UPH-1) obtained in example 1, 10 parts by mass of the polyfunctional isocyanate compound (I-11), 0.5 part by mass of the surfactant (S-11) having a cationic hydrophilic group, 1.0 part by mass of the antioxidant (C-1), and 100 parts by mass of ethyl acetate as a solvent, and stirring the mixture with a dispersing machine. The amounts of the respective materials other than the solvent used are expressed as nonvolatile components (the same applies to the other examples and comparative examples). The formulation composition is shown in Table 3-1.

A50 μm-thick polyethylene terephthalate (PET) film (Lumiler T-60, manufactured by Toray corporation) was prepared as a substrate sheet. The obtained urethane adhesive was applied to one surface of the substrate sheet using a comma wheel coater (registered trademark) so that the thickness after drying became 12 μm. Next, the formed coating layer was dried at 100 ℃ for 2 minutes to form a coherent layer. A release sheet ("Super Stik) SP-PET 38", manufactured by Lintec) was attached to the adhesive layer to a thickness of 38 μm to obtain an adhesive sheet.

The initial hardenability was evaluated after curing for 5 hours under 23 to 50% RH. For other evaluations, the evaluation was performed after 1 week of curing under the conditions of 23 to 50% RH.

(examples 2 to 42, comparative examples 1 to 5)

In examples 2 to 42 and comparative examples 1 to 5, the production of the urethane adhesive and the adhesive sheet and the evaluation thereof were carried out in the same manner as in example 1 except that the kind and the blending ratio of the materials used were changed as shown in tables 3-1 to 3-6 and table 4.

[ evaluation items and evaluation methods ]

Evaluation items and evaluation methods of the adhesive and the adhesive sheet are as follows.

(gel fraction)

Test pieces 30mm wide and 100mm long were cut from the adhesive sheet after 1 week of curing in an environment of 23-50% RH. The test piece was attached to a SUS net (mesh: 0.077mm, wire diameter: 0.05mm), and then immersed in ethyl acetate. After extraction at 50 ℃ for 24 hours, the gel fraction (% by mass) after curing was calculated based on the following formula (1) by drying at 100 ℃ for 30 minutes.

Gel fraction (% by mass) of (G2/G1) × 100 … (1)

In the formula, each symbol represents the following parameter.

G1: the quality of the adhesive layer before extraction with ethyl acetate,

G2: extraction with ethyl acetate and the quality of the dried adhesive layer.

(initial hardening)

Test pieces 30mm wide and 100mm long were cut from the adhesive sheet after 5 hours of curing in an environment of 23 to 50% RH. The test piece was attached to a SUS net (mesh: 0.077mm, wire diameter: 0.05mm), and then immersed in ethyl acetate. After extraction at 50 ℃ for 24 hours, and drying at 100 ℃ for 30 minutes, the initial gel fraction (% by mass) was calculated based on the following formula (2).

Initial gel fraction (% by mass) of (G4/G3) × 100 … (2)

In the formula, each symbol represents the following parameter.

G3: the quality of the adhesive layer before extraction with ethyl acetate,

G4: extraction with ethyl acetate and the quality of the dried adhesive layer.

The evaluation criteria are as follows.

Very good: the initial gel fraction was 70 mass% or more, and the results were excellent.

O: the initial gel fraction is preferably 40 mass% or more and less than 70 mass%.

And (delta): the initial gel fraction is 20 mass% or more and less than 40 mass%, and is practical.

X: the initial gel fraction was less than 20 mass%, and this was not practical.

(adhesive force before heating)

Test pieces having a width of 25mm and a length of 100mm were cut from the adhesive sheet after 1 week of curing in an environment of 23 to 50% RH. Subsequently, the release sheet was peeled from the test piece in an environment of 23 to 50% RH, and the exposed adhesive layer was attached to the surface of the sodium hydroxide glass plate, and pressure-bonded by reciprocating a 2kg roller once. Thereafter, the mixture was left to stand in an atmosphere of 23 to 50% RH for 24 hours. Then, the adhesive force (adhesive force before heating) was measured using a tensile tester (Tensilon, manufactured by Aiander, Inc.) at a peel speed of 300mm/min and a peel angle of 180 ℃ in accordance with JIS Z0237. The evaluation criteria are as follows.

Very good: less than 20mN/25mm, excellent.

O: 20mN/25mm or more and less than 50mN/25mm, good.

And (delta): more than 50mN/25mm and less than 200mN/25mm, and is practical.

X: 200mN/25mm or more, and is not practical.

(rate of increase in adhesive force after heating)

Test pieces having a width of 25mm and a length of 100mm were cut from the adhesive sheet after 1 week of curing in an environment of 23 to 50% RH. Subsequently, the release sheet was peeled from the test piece in an environment of 23 to 50% RH, and the exposed adhesive layer was attached to a sodium hydroxide glass plate, and pressure-bonded by reciprocating a 2kg roller once. Thereafter, the mixture was left at 150 ℃ for 1 hour. Then, after air-cooling for 30 minutes in an environment of 23 to 50% RH, the adhesion (adhesion after heating at 150 ℃ C.) was measured using a tensile tester (manufactured by Tensilon (TENSILON): Ahond (Orientec)) at a peeling speed of 300mm/min and a peeling angle of 180 ℃ in accordance with JIS Z0237. The rate of increase in the adhesive force after heating was calculated based on the following formula (3).

The rate of increase (%) of the adhesive force after heating was (N2/N1) × 100 … (3)

In the formula, each symbol represents the following parameter.

N1: evaluation 2 of the value of the adhesion before heating,

N2: the value of the adhesive force after heating at 150 ℃ measured in the evaluation 3.

The evaluation criteria are as follows.

Very good: less than 150%, excellent.

O: 150% or more and less than 300%, good.

And (delta): more than 300% and less than 500%, and is practical.

X: above 500%, it is not practical.

(adherend contamination inhibitory Property)

Two test pieces having a width of 70mm and a length of 100mm were cut from the adhesive sheet after 1 week of curing in an environment of 23 to 50% RH. For each test piece, the release sheet was peeled off in an environment of 23 to 50% RH, and a soda glass plate was attached to the surface of the exposed adhesive layer, followed by pressing with a laminator. One of the two laminates obtained was placed in an oven at 60-90% RH for 72 hours. The other stack was placed in an oven at 85-85% RH for 24 hours. After 2 laminates were taken out from the oven and air-cooled in an environment of 23 to 50% RH for 3 hours, the adhesive sheet was peeled off from the glass plate, and contamination of the adherend was evaluated. The surface of the glass plate on the side to which the adhesive sheet was attached was irradiated with a Light Emitting Diode (LED) lamp in a dark room, and was visually observed to evaluate. The evaluation criteria are as follows.

Very good: in the samples heated to either 60 to 90% RH or 85 to 85% RH, no adhesion of the adhesive layer component was observed on the glass surface, and the samples were excellent.

O: in the samples heated to a heating condition of 60 to 90% RH, no adhesion of the adhesive layer component was observed on the glass surface, but in the samples heated to a heating condition of 85 to 85% RH, adhesion of the adhesive layer component was observed to be thin at one to three sites on the glass surface, and was good.

And (delta): in the samples heated to a heating condition of 60 to 90% RH, adhesion of a thin adhesive layer component is observed at one to three sites on the glass surface, and in the samples heated to a heating condition of 85 to 85% RH, adhesion of a thin adhesive layer component is observed at four or more sites on the glass surface and/or adhesion of a thick adhesive layer component is observed at one to two sites on the glass surface, and therefore, it is practical.

X: in the samples heated to either 60 to 90% RH or 85 to 85% RH, adhesion of a thin adhesive layer component was observed at four or more positions on the glass surface and/or adhesion of a thick adhesive layer component was observed at one to two positions on the glass surface, which was not practical.

[ evaluation results ]

The evaluation results are shown in tables 3-1 to 3-6 and table 4.

In examples 1 to 42, the following urethane adhesive was produced, and the urethane adhesive included:

A polyfunctional isocyanate compound (I), and

a surfactant (S) having a cationic hydrophilic group,

the surfactant (S) has an amine value of 0.1 to 160mgKOH/g, preferably 0.1 to 150mgKOH/g in terms of nonvolatile matter,

In all of these examples, an adhesive having good initial curability, a small adhesive force before heating and a small increase rate of the adhesive force after heating at 150 ℃ were produced, and an adhesive sheet having little contamination of an adherend even when exposed to a moist heat environment was produced.

The adhesive sheet obtained in comparative example 1, in which the surfactant (S) having a cationic hydrophilic group and the other surfactant (R) were not added, was poor because the increase rate of the adhesive force after heating was large.

The pressure-sensitive adhesive sheet obtained in comparative example 2 in which the amount of the surfactant (S) having a cationic hydrophilic group added to 100 parts by mass of the active hydrogen group-containing compound (H) was more than 20 parts by mass had poor initial hardenability, a poor rate of increase in the adhesive force before heating and the adhesive force after heating, and the adherend was significantly contaminated.

The adhesive sheet obtained in comparative example 3, to which the comparative surfactant (R) having a cationic hydrophilic group and an amine value of more than 160mgKOH/g in terms of nonvolatile matter was added, was poor because the increase rate of the adhesive force after heating at 150 ℃ was large.

The adhesive sheets obtained in comparative examples 4 and 5, to which the comparative surfactant (R) having a cationic hydrophilic group and an amine value of less than 0.1mgKOH/g in terms of nonvolatile matter was added, had a large increase in adhesive strength after heating at 150 ℃ and were significantly contaminated with an adherend.

The present invention is not limited to the above-described embodiments and examples, and can be appropriately modified in design without departing from the spirit of the present invention.

The present application claims priority based on japanese application No. 2018-159967 filed on 29.8.2018, the entire disclosure of which is incorporated herein.

Description of the symbols

10. 20: adhesive sheet

11. 21: substrate sheet

12. 22A, 22B: adhesive layer

13. 23A, 23B: release sheet

Claims

1. A urethane adhesive comprising:

At least one polyfunctional isocyanate compound (I) and

one or more surfactants (S) having a cationic hydrophilic group,

2. The urethane adhesive according to claim 1, wherein the active hydrogen group-containing compound (H) is a hydroxyl-terminated Urethane Prepolymer (UPH) which is a reaction product of one or more active hydrogen group-containing compounds and one or more polyisocyanates.

3. The urethane-based adhesive according to claim 1 or 2, wherein the number of hydrophilic groups in the surfactant (S) is one.

4. The urethane adhesive according to claim 1 or 2, wherein the amine value of the surfactant (S) is from 0.1mgKOH/g to 60mgKOH/g in terms of nonvolatile matter.

5. The urethane adhesive according to claim 1 or 2, further comprising one or more deterioration inhibitors selected from the group consisting of an antioxidant, a hydrolysis resistance agent, an ultraviolet absorber, and a light stabilizer.

6. An adhesive sheet comprising: a substrate sheet, and an adhesive layer containing a cured product of the urethane adhesive according to any one of claims 1 to 5.