JP6516056B1 - Urethane pressure sensitive adhesive and adhesive sheet - Google Patents

Abstract

An object of the present invention is to reduce adhesion, exhibit good removability, and reduce adherent contamination after re-peeling, both in the initial stage (before time-lapsed) and after time-lapse (especially after heat aging). Provided is an adhesive capable of forming an adhesive layer. An adhesive according to the present invention comprises 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 a cation. And the surfactant (S) have an amine value of 0.1 to 160 mg KOH / g in terms of nonvolatile content, and an active hydrogen group-containing compound (H The urethane-based pressure-sensitive adhesive wherein the content of the surfactant (S) is 0.01 to 20 parts by mass with respect to 100 parts by mass. [Selected figure] Figure 1

Description

  The present invention relates to a urethane-based pressure-sensitive adhesive and a pressure-sensitive adhesive sheet.

DESCRIPTION OF RELATED ART Conventionally, the adhesive sheet in which the adhesion layer was formed on the base material sheet as a surface protection sheet of various members is used widely. Examples of the pressure-sensitive adhesive include acrylic pressure-sensitive adhesives, silicone-based pressure-sensitive adhesives, and urethane-based pressure-sensitive adhesives. Acrylic pressure-sensitive adhesives are excellent in adhesive strength, but because of their strong adhesive strength, their removability after being attached to an adherend is not good. In particular, after aging in a (wet) heat environment, the removability is further reduced due to the increase in adhesive strength, and the adhesive tends to remain on the surface of the adherend after re-peeling. is there. The silicone-based pressure-sensitive adhesive is liable to cause contamination of the adherend, and furthermore, a silicone resin having a relatively low molecular weight volatilizes and may be adsorbed on the surface of an apparatus such as an electronic device to cause a problem. On the other hand, the urethane-based pressure-sensitive adhesive has excellent adhesion to the adherend, is also relatively excellent in removability, and hardly volatilizes.
In the present specification, the “pressure-sensitive adhesive” is a pressure-sensitive adhesive (re-peelable pressure-sensitive adhesive) having removability, and the “pressure-sensitive adhesive sheet” is a pressure-sensitive adhesive sheet (re-peelable pressure-sensitive adhesive sheet) having removability.

Flat panel displays such as liquid crystal displays (LCDs) and organic electroluminescent displays (OELDs), and touch panel displays combining such flat panel displays and touch panels are used for TVs (TVs), personal computers (PCs), mobile phones, and It is widely used in electronic devices such as portable information terminals.
The urethane-based pressure-sensitive adhesive sheet is a flat panel display and a touch panel display, and a substrate manufactured or used in these manufacturing steps (a glass substrate, and an ITO / glass substrate having an ITO (indium tin oxide) film formed on the glass substrate) Etc. and optical members etc. are suitably used as surface protection sheets.

  As a method for producing a urethane-based pressure-sensitive adhesive, a method 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 hydroxyl-terminated urethane prepolymer Instead, there is a method (one-shot method) in which an active hydrogen group-containing compound such as a polyol and a polyfunctional isocyanate compound are reacted at one time.

  A general method for producing a pressure-sensitive adhesive sheet comprises a step of applying a pressure-sensitive adhesive onto a substrate sheet, and heat-drying the formed coating layer to form a pressure-sensitive adhesive layer containing a cured product of the pressure-sensitive adhesive. It includes a heating step, a winding step of winding the obtained pressure-sensitive adhesive sheet around a core to form a pressure-sensitive adhesive sheet roll, and a curing step of curing the pressure-sensitive adhesive sheet roll.

JP, 2014-162821, A Japanese Patent Laid-Open No. 2018-062628 JP, 2015-172202, A JP, 2011-037928, A

  Curing proceeds immediately after production of the urethane-based pressure-sensitive adhesive, but when the initial curing property is low, the coated layer or the adhesive layer is formed by hot air during heating and drying of the coated layer, or winding of the pressure-sensitive adhesive sheet obtained after heating and drying Under the influence of mechanical stress received at the time of curing and at the time of curing, there may be surface appearance defects such as winding core step marks, wrinkles, and wrinkles in the adhesive layer. The urethane-based pressure-sensitive adhesive preferably has a good initial curing property while having a good pot life.

  The pressure-sensitive adhesive sheet has good removability which can be easily re-peeled from the adherend when it is removed from the adherend, both in the initial stage (before aging) and after the aging (in particular, after (wet) heat aging). Is preferred. Conventionally, in general, the pressure-sensitive adhesive sheet has high anchorability between the adherend and the pressure-sensitive adhesive layer when exposed to a (humid) thermal environment, and as a result, the adhesive strength of the pressure-sensitive adhesive layer is increased. There is a tendency to decline. It is preferable that the pressure-sensitive adhesive sheet has good removability even when exposed to a (wet) heat environment and that there is no contamination of the adherend with the pressure-sensitive adhesive component remaining on the surface of the adherend after re-peeling.

  Although details will be described later, Patent Documents 1 to 4 can be mentioned as related documents of the present invention.

  The present invention has been made in view of the above-mentioned circumstances, and the initial curing property is good, and the adhesive strength is reduced both in the initial stage (before time-lapse) and after time-lapse (especially after (moist) heat time-lapse) It is an object of the present invention to provide a pressure-sensitive adhesive which is capable of forming a pressure-sensitive adhesive layer which has the following removability and which less adheres to the adherend after re-peeling, and a pressure sensitive adhesive sheet using the same.

The pressure-sensitive adhesive of the present invention is
At least one active hydrogen group-containing compound (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 0.1 to 160 mg KOH / g in terms of nonvolatile content,
It is a urethane type adhesive which is 0.01-20 mass parts in content of surfactant (S) with respect to 100 mass parts of active hydrogen group containing compounds (H).

  The pressure-sensitive adhesive sheet of the present invention comprises a substrate sheet and a pressure-sensitive adhesive layer comprising a cured product of the pressure-sensitive adhesive of the present invention described above.

  In the present specification, “Mw” is a polystyrene-equivalent weight average molecular weight determined by gel permeation chromatography (GPC) measurement. "Mn" is the polystyrene equivalent number average molecular weight determined by GPC measurement. These can be measured by the method described in the [Example] section.

  According to the present invention, the initial curing property is good, and the adhesive strength is reduced and has good removability both in the initial stage (before the aging) and after the aging (in particular, after the (wet) heat aging). It is possible to provide a pressure-sensitive adhesive capable of forming a pressure-sensitive adhesive layer with less contamination of adherend after re-peeling, and a pressure-sensitive adhesive sheet using the same.

It is a schematic cross section of the adhesive sheet of 1st Embodiment which concerns on this invention. It is a schematic cross section of the adhesive sheet of 2nd Embodiment which concerns on this invention.

[Urethane-based adhesive]
The pressure-sensitive adhesive of the present invention is
At least one active hydrogen group-containing compound (H) having a plurality of active hydrogen groups in one molecule, at least one polyfunctional isocyanate compound (I), and at least one surfactant having a cationic hydrophilic group It is a urethane type adhesive which contains an agent (S).
In the pressure-sensitive adhesive of the present invention, the surfactant (S) has an amine value of 0.1 to 160 mg KOH / g in terms of nonvolatile content, and the surfactant (S) per 100 parts by mass of the active hydrogen group-containing compound (H) The content is 0.01 to 20 parts by mass.
The pressure-sensitive adhesive sheet of the present invention is a urethane-based pressure-sensitive adhesive sheet including a substrate sheet and a pressure-sensitive adhesive layer comprising a cured product of the above-mentioned pressure-sensitive 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.
Examples of the active hydrogen group include a hydroxyl group (hydroxy group), a mercapto group, and an amino group (in the present specification, unless otherwise specified, the amino group includes an imino group). The active hydrogen group-containing compound (H) includes a polyol having a plurality of hydroxyl groups in one molecule, a polyamine having a plurality of amino groups in one molecule, an amino alcohol having an amino group and a hydroxyl group in one molecule, and Among them, polythiols having a plurality of mercapto groups can be mentioned. These active hydrogen group-containing compounds (H) may be non-polymers or polymers. These can be used alone or in combination of two or more.
Among these, polyols are preferred. Since polyamines and polythiols have high reactivity and short pot life, it is preferable to use them in combination with polyols when using them. In addition, when the active hydrogen group of the polyol is a secondary hydroxyl group, the initial curing property of the urethane-based pressure-sensitive adhesive does not improve, so from the viewpoint of the pot life and the initial curing property, the polyol has a primary hydroxyl group with appropriate reactivity. It is preferable to include.

(Hydroxyl-terminated urethane prepolymer (UPH))
As the active hydrogen group-containing compound (H), a hydroxyl group-terminated urethane which is a reaction product obtained by copolymerizing one or more active hydrogen group-containing compounds (HX) and one or more polyisocyanates (N) Prepolymers (UPH) are preferred. The copolymerization reaction can be carried out in the presence of one or more catalysts, if necessary. If necessary, one or more solvents can be used for the copolymerization reaction.

<Active hydrogen group-containing compound (HX)>
Examples of the polyol that can be used as the active hydrogen group-containing compound (HX) include polyester polyols, polyether polyols, polyacrylic polyols, polycaprolactone polyols, polycarbonate polyols, and castor oil-based polyols. Among them, polyester polyols, polyether polyols, and combinations thereof are preferred.

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

  As a polyol component of the raw material, 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-propanediol Hexanediol (1,3-octanediol), 1,8-octanediol, 1,9-nonanediol, 2-methyl-1,8-octanediol, 1,8-decanediol, octadecanediol, glycerin, trimethylol Examples thereof include propane, pentaerythritol, and hexanetriol.

  As the acid component of the raw material, succinic acid, methyl succinic 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, 4,4'-biphenyldicarboxylic acid, and their acid anhydrides Etc.

  As a polyether polyol which can be used as an active hydrogen group containing compound (HX), a well-known thing can be used. Examples of polyether polyols include compounds (addition polymers) obtained by addition polymerization of one or more oxirane 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, ethylene glycol (EG), propylene glycol (PG), 1,4-butanediol, neopentyl glycol, butylethyl pentanediol, N-aminoethyl ethanolamine, isophorone diamine, and xylylene diamine 2 Functional initiators; trifunctional initiators such as glycerin, trimethylolpropane and triethanolamine; tetrafunctional initiators such as pentaerythritol, ethylenediamine and aromatic diamine; and pentafunctional initiators such as diethylenetriamine.
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.

  As the polyether polyol, an alkylene oxide adduct of an active hydrogen-containing compound (also referred to as polyoxyalkylene polyol) is preferable. Among them, bifunctional polyether polyols such as polyethylene glycol (PEG), polypropylene glycol (PPG), PPG (PPG-EO) having ethylene oxide (EO) added at the end, and polyalkylene glycol such as polytetramethylene glycol; Preferred are trifunctional polyether polyols such as alkylene oxide adducts of glycerin and the like.

The degree of unsaturation of the polyether polyol is preferably low. The degree of unsaturation refers to the total amount of unsaturated groups contained per gram of polyether polyol and corresponds to the amount of impurity monool. By using a high purity material having a low degree of unsaturation, the initial curing property of the pressure-sensitive adhesive is improved, and particularly on the surface of an adherend after re-peeling of the pressure-sensitive adhesive sheet when exposed to a (wet) heat environment. It is possible to suppress the contamination of the adherend where the adhesive component remains. The degree of unsaturation of the polyether polyol is preferably at most 0.07 meq / g, more preferably at most 0.04 meq / g, particularly preferably at most 0.01 meq / g.
In the present specification, unless otherwise specified, the degree of unsaturation of the polyol is a value measured in accordance with JIS K1557 6.7.

  Examples of the polyamine which can be used as the active hydrogen group-containing compound (HX) include ethylenediamine, 1,2-propanediamine, 1,3-propanediamine, 1,4-butanediamine, 1,5-pentanediamine, 1,6 Hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,12-dodecanediamine, 1,14-tetradecanediamine, 1,16-hexadecane Diamine, hexamethylenediamine, trimethylhexamethylenediamine, iminobispropylamine, methyliminobispropylamine, 1,5-diamino-2-methylpentane, isophoronediamine, 1,3-bisaminomethylcyclohexane, 1-cyclohexylamino- 3-aminopro , 3-aminomethyl-3,3,5-trimethyl-cyclohexylamine, dimethyleneamine of norbornane skeleton, metaxylylenediamine (MXDA), hexamethylenediamine carbamate, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and Aliphatic polyamines such as pentaethylenehexamine; 3,3'-dichloro-4,4'-diaminodiphenylmethane (MOCA), 4,4'-diaminodiphenylmethane, 2,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane 3,4'-diaminodiphenylmethane, 2,2'-diaminobiphenyl, 3,3'-diaminobiphenyl, 2,4-diaminophenol, 2,5-diaminophenol, o-phenylenediamine, m-phenylene Diamines, p-phenylenediamine, 2,3-tolylenediamine, 2,4-tolylenediamine, 2,5-tolylenediamine, 2,6-tolylenediamine, 3,4-tolylenediamine, and diethyltoluene And aromatic polyamines such as diamine;

  Examples of amino alcohols which can be used as the active hydrogen group-containing compound (HX) include monoethanolamine, diethanolamine, 2-amino-2-methyl-1-propanol, tri (hydroxymethyl) aminomethane, and 2-amino-2 -Monoamines having a hydroxyl group such as ethyl 1,3-propanediol; diamines having a hydroxyl group such as N- (2-hydroxypropyl) ethanolamine; and the like.

  Examples of polythiols that can be used as the active hydrogen group-containing compound (HX) include methanedithiol, 1,3-butanedithiol, 1,4-butanedithiol, 2,3-butanedithiol, 1,2-benzenedithiol, 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-propadithiol, toluene-3,4-dithiol, 3,6-dichloro-1,2-benzenedithiol, 1,5-naphthalenedithiol, 1,2- Benzenedimethanethiol, 1,3-benzenedimethanethiol, 1,4-benzenedimer Thiol, 4,4'-thiobisbenzenethiol, 2,5-dimercapto-1,3,4-thiadiazole, 1,8-dimercapto-3,6-dioxaoctane, 1,5-dimercapto-3-thiapentane, Examples thereof include 2-di-n-butylamino-4,6-dimercapto-s-triazine, thiol group-terminated polymers (polysulfide polymers and the like), and the like.

The one or more active hydrogen group-containing compounds (HX) can include a bifunctional active hydrogen group-containing compound and / or a trifunctional or higher functional 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. By selecting the number of functional groups (the number of active hydrogen groups) of each active hydrogen group-containing compound (HX), it is possible to adjust the properties such as the adhesive strength, cohesion and removability of the urethane-based pressure-sensitive adhesive. Depending on the application etc., the functional group number of each material can be selected so that the properties such as adhesive strength, cohesion and removability fall within a preferable range.
At least one active hydrogen group-containing compound (HX) contains a bifunctional active hydrogen group-containing compound and a trifunctional or higher active hydrogen group-containing compound, since adhesion and removability are easily achieved. Is preferred.

  The number average molecular weight (Mn) per functional group of the active hydrogen group-containing compound (HX) is not particularly limited. Preferably, the one or more active hydrogen group-containing compounds (HX) have a Mn of 500 or more, more preferably 1000 or more, particularly preferably 2000 or more, and most preferably, because the adhesion and wettability of the adhesive layer are suitable. Preferably contain an active hydrogen group-containing compound of 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 group-terminated urethane prepolymer (UPH) is increased to increase the adhesion of the adhesive layer. 2.) Under the thermal environment, there is a possibility that adherend contamination may occur after re-peeling. 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 relatively small, and the adherent contamination after re-peeling is suppressed Can. From the viewpoint of pot life and initial curability, the active hydrogen group-containing compound (HX) preferably contains a primary terminal hydroxyl group.

<Polyisocyanate (N)>
Known polyisocyanates can be used as the polyisocyanate (N), and aromatic polyisocyanates, aliphatic polyisocyanates, alicyclic polyisocyanates, and the like can be mentioned.

  As the aromatic polyisocyanate, 1,3-phenylene diisocyanate, 4,4'-diphenyl diisocyanate, 1,4-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6-triisocyanate Diisocyanate, 4,4'-toluidine diisocyanate, 2,4,6-triisocyanate toluene, 1,3,5-triisocyanatobenzene, dianisidine diisocyanate, 4,4'-diphenylether diisocyanate, and 4,4 ', 4 “-Triphenylmethane triisocyanate, ω, ω′-diisocyanate-1,3-dimethylbenzene, ω, ω′-diisocyanate-1,4-dimethylbenzene, ω, ω′-diisocyanate-1,4-diethylbenzene 1,4-tetramethyl xylylene diisocyanate, and 1,3-tetramethylxylylene diisocyanate and the like.

  As aliphatic polyisocyanate, 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.

  As alicyclic polyisocyanate, isophorone diisocyanate (IPDI), 1,3-cyclopentadiisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, methyl-2,4-cyclohexane diisocyanate, methyl-2, 6 -Cyclohexane diisocyanate, 4,4'- methylene bis (cyclohexyl isocyanate), and 1, 4- bis (isocyanato methyl) cyclohexane etc. are mentioned.

  In addition, examples of the polyisocyanate include trimethylolpropane adduct, biuret, allophanate, and trimer of the above-mentioned polyisocyanate (the trimer includes an isocyanurate ring).

  Aliphatic polyisocyanate or alicyclic polyisocyanate is preferable as the polyisocyanate (N) from the viewpoint of reducing the adhesive strength in the initial stage (before time lapse) and after time lapse (in particular, after (wet) heat time course), hexamethylene diisocyanate ( More preferred are HDI) and isophorone diisocyanate (IPDI).

The preferable raw material compounding ratio of a hydroxyl group terminal urethane prepolymer (UPH) is as follows.
The ratio of the number of moles of isocyanate groups (NCO) possessed by polyisocyanate (N) to the total number of moles of active hydrogen groups (H) possessed by a plurality of active hydrogen group-containing compounds (HX) (NCO / H ratio) is 0. It is preferable to determine the raw material blending ratio so as to be 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 to be gelled during synthesis of the hydroxyl terminated urethane prepolymer (UPH). When the NCO / H ratio is 0.95 or less, gelation at the time of synthesis of a hydroxyl group-terminated urethane prepolymer (UPH) can be effectively suppressed.

<Catalyst>
If necessary, one or more catalysts can be used for the polymerization of the hydroxyl group-terminated urethane prepolymer (UPH). A well-known thing can be used as a catalyst, A tertiary amine type compound, an organometallic type compound, etc. are mentioned.
Examples of tertiary amine compounds include triethylamine, triethylenediamine, and 1,8-diazabicyclo (5,4,0) -undecene-7 (DBU).
Examples of organic metal compounds include tin compounds and non-tin compounds.
Examples of tin compounds include dibutyltin dichloride, dibutyltin oxide, dibutyltin dibromide, dibutyltin dimaleate, dibutyltin dilaurate (DBTDL), dibutyltin diacetate, dioctyltin dilaurate, dibutyltin sulfide, tributyltin sulfide, and tributyltin oxide. And tributyl tin acetate, triethyl tin ethoxide, tributyl tin ethoxide, dioctyl tin oxide, tributyl tin chloride, tributyl tin trichloroacetate, tin 2-ethylhexanoate and the like.
Examples of non-tin compounds include titanium such as dibutyl titanium dichloride, tetrabutyl titanate, and butoxy titanium trichloride; lead such as lead oleate, lead 2-ethylhexanoate, lead benzoate, and lead naphthenate; 2 -Iron based such as iron and ethyl acetyl hexanoate; cobalt based such as cobalt benzoate and cobalt 2-ethyl hexanoate; zinc based such as zinc naphthenate and zinc 2-ethyl hexanoate such as zirconium naphthenate A zirconium system is mentioned.
The type and addition amount of the catalyst can be appropriately designed within the range in which the reaction proceeds favorably.

When two or more active hydrogen group-containing compounds (HX) having different reactivities are used in combination, there is a risk that poor polymerization stability or white turbidity of the reaction solution may easily occur in a single catalyst system due to the difference in reactivity. is there. In this case, by using two or more types of catalysts, it is easy to control the reaction (for example, the reaction rate etc.), and the above problem can be solved. In a system in which a plurality of active hydrogen group-containing compounds (HX) having different reactivities are used 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 amines / organic metals, tin-based / non-tin-based, and tin-based / tin-baseds. Preferred are tin-based / tin-based, more preferably dioctyl tin dilaurate and tin 2-ethylhexanoate.
The mass ratio of tin 2-ethylhexanoate to dioctyltin dilaurate (tin 2-ethylhexanoate / dioctyltin dilaurate) is not particularly limited, and is preferably more than 0 and less than 1, more preferably 0.2 to 0.8. is there. If the mass ratio is less than 1, catalyst activity is well balanced, gelation and white turbidity of the reaction solution are effectively suppressed, and polymerization stability is further improved.

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

<Solvent>
If necessary, one or more solvents can be used for the polymerization of the hydroxyl group-terminated urethane prepolymer (UPH). Known solvents can be used as the solvent, and methyl ethyl ketone, ethyl acetate, toluene, xylene, acetone and the like can be mentioned. Ethyl acetate, toluene and the like are particularly preferable in view of the solubility of the hydroxyl group-terminated urethane prepolymer (UPH) and the boiling point of the solvent.

<Polymerization Method of Hydroxyl-Terminated Urethane Prepolymer (UPH)>
The polymerization method of the hydroxyl group-terminated urethane prepolymer (UPH) is not particularly limited, and known polymerization methods such as bulk polymerization and solution polymerization can be applied.
As a polymerization procedure of a hydroxyl group terminal urethane prepolymer (UPH),
Procedure 1) One or more active hydrogen group-containing compounds (HX), one or more polyisocyanates (N), if necessary, one or more catalysts, and if necessary, one or more solvents, collectively Procedure for charging flasks;
Procedure 2) A flask is charged with one or more active hydrogen group-containing compounds (HX), optionally one or more catalysts, and optionally one or more solvents, and one or more polyisocyanates (this is added to the flask) The procedure of dripping addition of N etc., etc. are mentioned.
When two or more active hydrogen group-containing compounds (HX) and / or polyisocyanates (N) are used, the reaction may be performed in multiple steps.

  The reaction temperature when using a catalyst is preferably less than 100 ° C., more preferably 50 to 95 ° C., particularly preferably 60 to 85 ° C. When the reaction temperature is 100 ° C. or higher, control of the reaction rate, polymerization stability and the like becomes difficult, and there is a possibility that the formation of a hydroxyl group-terminated urethane prepolymer (UPH) having a desired molecular weight becomes difficult. The reaction temperature when no catalyst is used is preferably 100 ° C. or more, more preferably 110 ° C. or more.

(Multifunctional isocyanate compound (I))
As the polyfunctional isocyanate compound (I), known compounds can be used, and compounds exemplified as the polyisocyanate (N) which is a raw material of the hydroxyl group-terminated urethane prepolymer (UPH) (specifically, aromatic polyisocyanate, aliphatic Polyisocyanates, araliphatic polyisocyanates, alicyclic polyisocyanates and their trimethylolpropane adduct / biuret / allophanate / 3-mer) can be used.

(Surfactant having a cationic hydrophilic group (S))
The pressure-sensitive adhesive of the present invention contains one or more surfactant (S) having a cationic hydrophilic group, which has an amine value of 0.1 to 160 mg KOH / g in terms of nonvolatile content.
As the surfactant (S), one or more of known cationic surfactants and / or amphoteric surfactants can be used, and the amine value is 0.1 to 160 mg KOH / g in terms of nonvolatile content. There is no particular limitation if it is. Examples of the cationic hydrophilic group include primary to tertiary amino groups, primary to tertiary amine bases, and quaternary ammonium bases.
In addition, even if the commercially available surfactant is unknown in its structure or composition, a surfactant having an amine value of 0.1 to 160 mg KOH / g in terms of nonvolatile content is selected as the surfactant (S). Just do it. One commercially available surfactant having such an amine value may contain a plurality of different cationic hydrophilic groups.

As specific examples of commercially available cationic surfactants or amphoteric surfactants which can be used as the surfactant (S),
Solspurs 9000, Solspars 11200, Solspars 13240, Solspars 13940, Solspars 16000, Solspars 17000, Solspars 18000, Solspars 20000, Solspars 24000SC, Solspars 24000, Solspars 26000, Solspars 28000, Solspars 31845, Solspars 32500, Solspars 32500 Solspars 32550, Solspars 32600, Solspars 33000, Solspars 34750, Solspars 35100, Solspars 35200, Solspars 37500, Solspars 38500, Solspars 39000, Solspars 53095, Solspars 56000, Solspars 71 00, SOLSPERSE 76500, SOLSPERSE D510, SOLSPERSE D530, SOLSPERSE L300, SOLSPERSE K200, SOLSPERSE K210, SOLSPERSE K500, Solsperse R700;
Kyoei Co., Ltd. Floren DOPA-15B, Floren DOPA-15BHFS, Floren DOPA-17HF, Floren DOPA-22, Floren DOPA-35, Floren G-600, Floren G-820, Floren NC-500, Floren KDG-2400;
Hinoac KF-1300M, Hinoacto KF-1500, Hinoacto KF-1700, Hinoacto T-6000, Hinoacto T-8000, Hinoacto T-8000E, Hinoacto T-9100, Hinoacto A-110, Hinoacto NB, manufactured by Kawaken Fine Chemical Co.
Evonik TEGODispers 650, TEGODispers 660C, TEGODispers 662C, TEGODispers 670, TEGODispers 685, TEGODispers 700, TEGODispers 710, TEGODispers 760W;
Ajinomoto Fine Techno Co., Ltd. Ajispar PB 821, Ajisper PB 822, Agisper PB 824, Agisper PB 881,
BICK CHEMY DISPERBYK-106, DISPERBYK-108, DISPERBYK-140, DISPERBYK-142, DISPERBYK-145, DISPERBYK-161, DISPERBYK-162, DISPERBYK-163, DISPERBYK-164, DISPERBYK-164, DISPERBYK-167, DISPERBYK-168, DISPERBYK-168, DISPERBYK- 180, DISPERBYK-182, DISPERBYK-184, DISPERBYK-185, DISPERBYK-2000, DISPERBYK-2001, DISPERBYK-2008, DISPERBYK-2009, DISPERBYK-2013, DISPERBYK-2013, DISPERBYK-222, DISPERBYK-2025, DISPERBYK 2026, DISPERBYK-2050, DISPERBYK-2055, DISPERBYK-2150, DISPERBYK-2155, DISPERBYK-2163, DISPERBYK-2164, BYK-9076, BYK-9077, ANTI-TERRA-U / U100, ANTI-TERRA-204, ANTI- TERRA-250, DISPERBYK, DISPERBYK-180, DISPERBYK-184, DISPERBYK-185, DISPERBYK-187, DISPERBYK-191, DISPERBYK-2010, DISPERBYK-2012, DISPERBYK-2012, DISPERBYK-2012, DISPERBYK-022, DISPERBYK-2025, DISPERBYK-2026, D Pigment dispersing agents such as SPERBYK-2050, DISPERBYK-2055, DISPERBYK-2061;
NOF Corporation Filanol PA-075F, Filanol PA-085C, Filanol PA-107P, Esleam AD-3172M, Esleem AD-374M, Esleem AD-508E;
Charol DC 902 P, Charol DC 303 P manufactured by Daiichi Kogyo Seiyaku Co., Ltd .;
Polymer surfactants such as Teksnol IL 55, Teksnol L7, Teksnol CP-81, manufactured by Nippon Emulsifier, and the like.

By adding one or more surfactants (S) having a cationic hydrophilic group to the adhesive containing the active hydrogen group-containing compound (H) and the polyfunctional isocyanate compound (I), before and after the passage of time The adhesive strength of the adhesive layer can be reduced, and the increase in the adhesive strength of the adhesive layer in a (wet) heat environment can be suppressed. As a result, even when exposed to a (wet) heat environment, it is possible to form a pressure-sensitive adhesive layer having good removability and having no adhesive component remaining on the surface of the adherend after re-peeling. It becomes possible.
Although this mechanism is not necessarily clear, it is guessed as follows.
A glass substrate, an ITO / glass substrate having an ITO (indium tin oxide) film formed on the glass substrate, and a surfactant having a cationic hydrophilic group for interfacial interaction between an adherend such as an optical member and an adhesive layer ( It is thought that the adhesive layer becomes less adhesive and the removability is improved by cutting off S) both before and after the passage of time.

If the amine value of non-volatile matter equivalent of surfactant (S) is 0.1 mg KOH / g or more, the above-mentioned effect (especially (wet)) of the adhesive layer becoming less adhesive in the heat environment and its removability Enhancement and reduction of adherent contamination) can be significantly expressed.
If the amine value of the surfactant (S) is too high, the interaction between the adherend and the surfactant (S) becomes too large, so particularly under the (wet) heat environment, the surfactant (S) Bleed out may occur and adherent contamination may occur after re-peeling. If the amine value is 160 mg KOH / g or less in terms of nonvolatile content, it is considered that the interaction between the adherend and the adhesive layer can be cut off while suppressing the bleed out of the surfactant (S).

  The amine value is converted to non-volatile content, as the above-mentioned effects (in particular, the reduction of the adhesive strength of the adhesive layer under the (moist) heat environment and the improvement of the removability and the reduction of the adherend contamination thereby effectively appear) , Preferably 0.1 to 150 mg KOH / g, more preferably 0.1 to 100 mg KOH / g, particularly preferably 0.1 to 60 mg KOH / g, and most preferably 0.1 to 30 mg KOH / g.

  The acid value of the surfactant (S) is not particularly limited, and is preferably smaller. The acid value is preferably 40 mg KOH / g or less, and more preferably, in terms of non-volatile content, from the viewpoints of the initial curing property, and the improvement of the adhesion strength of the adhesive layer under the (humid) heat environment and the removability thereby. Is 20 mg KOH / g or less, particularly preferably 10 mg KOH / g or less, and most preferably 0 mg KOH / g.

An amine value, an acid value, and a non volatile matter can be measured by the following method.
<Amine value>
1 g of a sample is precisely weighed in a stoppered Erlenmeyer flask, 100 ml of a mixed solution of toluene / ethanol (volume ratio: toluene / ethanol = 1/1) is added and dissolved, and then 0.1 N-alcoholic hydrochloric acid solution is used Perform a titration. The amine value (unit: mg KOH / g) is determined by the following formula.
Amine value = {(5.61 × a × F) / S} / (non volatile matter concentration / 100)
In the formula, each symbol indicates the following parameter.
S: amount of sample collected (g),
a: consumption of 0.1 N-alcoholic hydrochloric acid solution (ml),
F: Factor of 0.1 N-alcoholic hydrochloric acid solution.
<Acid number>
Accurately measure 1 g of a sample in a stoppered Erlenmeyer flask, add 100 ml of a mixture of toluene / ethanol (volume ratio: toluene / ethanol = 2/1) and dissolve, and then dissolve with 0.1N alcoholic potassium hydroxide solution Use the titration. The acid value (unit: mg KOH / g) is determined by the following formula.
Acid value = {(5.61 × a × F) / S} / (nonvolatile content concentration / 100)
In the formula, each symbol indicates the following parameter.
S: amount of sample collected (g),
a: consumption of 0.1 N alcoholic potassium hydroxide solution (ml),
F: Factor of 0.1 N alcoholic potassium hydroxide solution.

<Non-volatile content>
About 1 g of the sample solution is weighed in a metal container, dried in an oven at 150 ° C. for 20 minutes, the residue is weighed to calculate the residue, and this is taken as the non-volatile content (non-volatile content concentration).

The weight average molecular weight (Mw) of the surfactant (S) is not particularly limited, and is preferably 500 or more, more preferably 1000 or more, and particularly preferably 2000 or more. By having Mw of 500 or more, the bleed out of the surfactant (S) after aging (particularly after (wet) heat aging) can be effectively suppressed, and the adherend contamination can be improved.
The weight average molecular weight (Mw) of surfactant (S) can employ a catalog value or a measured value.
The weight average molecular weight (Mw) can be determined by the method described in the [Example] section.

As related documents of the present invention, there are Patent Documents 1 to 4 listed in the "Background Art" section.
Patent Document 1 describes a pressure-sensitive adhesive sheet (surface protective film) using a urethane-based pressure-sensitive adhesive containing a leveling agent (claim 7). A surfactant can be used as a leveling agent. However, this document does not describe a surfactant having a cationic hydrophilic group, and does not describe or suggest addition of a surfactant having a specific amine value having a cationic hydrophilic group and its effect.

  Patent Document 2 discloses a pressure-sensitive adhesive containing a polyurethane resin (A) having a hydroxyl group, a reactive compound (B) having a functional group capable of reacting with a hydroxyl group, and a surfactant (C) ( Claim 1). As surfactant (C), anionic surfactant, cationic surfactant, amphoteric surfactant, and nonionic surfactant are mentioned (paragraph 0124).

  Patent Document 3 describes a pressure-sensitive adhesive sheet (surface protective film) using a urethane-based pressure-sensitive adhesive containing an antistatic agent (AS agent) (claim 3, paragraph 0022). As the antistatic agent, nonionic, cationic, anionic and amphoteric surfactants are mentioned (paragraph 0023).

Patent Document 4 discloses
Urethane urea resin (A) formed 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 a fluorine atom-containing anion as a part of the component,
A curing agent (C),
An antistatic pressure-sensitive adhesive composition is disclosed which comprises a silane coupling agent (D) having an alkoxysilyl group (Claim 1).
In the above composition, an ionic compound (B) is used as an antistatic agent. In Comparative Examples 21 and 24, in Patent Document 4, alkyl bis (2-hydroxyethyl) methyl ammonium chloride as a cationic surfactant is 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 having a cationic hydrophilic group to a urethane-based pressure-sensitive adhesive and its function and effect.
In addition, the code | symbol of each component of patent documents 1-4 is a code | symbol described in these documents, and it has nothing to do with the code | symbol used for each component of this invention.

  As a skeleton structure of 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 any may be used. The above effects (in particular, the reduction of the adhesive strength of the adhesive layer under the (moist) heat environment and the improvement of the removability by it and the reduction of the adherend contamination) are effectively exhibited, so the number of hydrophilic groups is 1 The single type is preferred.

(Plasticizer (P))
The adhesive of the present invention may further contain one or more plasticizers (P), if necessary, from the viewpoint of decreasing the adhesive strength of the adhesive layer and improving the wettability. The plasticizer (P) is not particularly limited, and is preferably an organic acid ester from the viewpoint of compatibility with other components.

  Examples of esters of monobasic acids or polybasic acids with alcohols include, for example, isostearyl laurate, isopropyl myristate, isocetyl myristate, octyldodecyl myristate, isostearyl palmitate, isocetyl stearate, octyldodecyl oleate, phthalate Dibutyl phthalate, dioctyl phthalate, diheptyl phthalate, dibenzyl phthalate, butyl benzyl phthalate, diisodecyl adipate, diisostearyl adipate, dibutyl sebacate, diisocetyl sebacate, tributyl acetyl citrate, tributyl trimellitate, trimellit Examples thereof include trioctyl acid, trihexyl trimellitate, trioleyl trimellitate, and triisocetyl trimellitate.

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

  Examples of esters of monobasic acids or polybasic acids with polyalkylene glycols include polyethylene glycol dihexylate, polyethylene glycol di-2-ethylhexylate, polyethylene glycol dilaurate, polyethylene glycol dioleate, and dipolyethylene glycol methyl adipate. Ether etc. are mentioned.

  From the viewpoint of improving wettability and the like, 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.

  It is preferable that the amount of the plasticizer (P) be small from the viewpoint of suppressing the contamination of the adherend. The amount of one or more plasticizers (P) relative to 100 parts by mass of the active hydrogen group-containing compound (H) 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.

(solvent)
The pressure-sensitive adhesive of the present invention may optionally contain one or more solvents. Known solvents can be used as the solvent, and methyl ethyl ketone, ethyl acetate, toluene, xylene, acetone and the like can be mentioned. From the viewpoint of the solubility of the active hydrogen group-containing compound (H) and the boiling point of the solvent, ethyl acetate and toluene are particularly preferable.

(Anti-deterioration agent)
The pressure-sensitive adhesive of the present invention can optionally contain one or more alteration inhibitors. Thereby, the fall of the various characteristics by long-term use of the adhesion layer can be suppressed. As the deterioration preventing agent, a hydrolysis resistant agent, an antioxidant, an ultraviolet light absorber, a light stabilizer and the like can be mentioned.

<Hydrolysis resistant agent>
When a hydrolysis reaction occurs in the adhesive layer in a (humid) thermal environment or the like to generate a carboxy group, a hydrolysis resistant agent can be used to block the carboxy group. As a hydrolysis resistance, a carbodiimide type, an oxazoline type, an epoxy type etc. are mentioned. Among them, carbodiimides are preferable from the viewpoint of the hydrolysis inhibitory effect.

The carbodiimide hydrolysis inhibitor is a compound having one or more carbodiimide groups in one molecule.
Examples of monocarbodiimide compounds include dicyclohexyl carbodiimide, diisopropyl carbodiimide, dimethyl carbodiimide, diisobutyl carbodiimide, dioctyl carbodiimide, diphenyl carbodiimide, and naphthyl carbodiimide.
The polycarbodiimide compound can be produced by the decarboxylation condensation reaction of diisocyanate in the presence of a carbodiimidization catalyst. Here, as the diisocyanate, for example, 4,4′-diphenylmethane diisocyanate, 3,3′-dimethoxy-4,4′-diphenylmethane diisocyanate, 3,3′-dimethyl-4,4′-diphenylmethane diisocyanate, 4,4 '-Diphenylether diisocyanate, 3,3'-dimethyl-4,4'-diphenylether diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1-methoxyphenyl-2,4-diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, and tetramethyl xylylene diisocyanate. As a carbodiimidization catalyst, 1-phenyl-2-phospholene-1-oxide, 3-methyl-2-phospholene-1-oxide, 1-ethyl-3-methyl-2-phospholene-1-oxide, 1-ethyl- 2-phospholene-1-oxide, and phosphorene oxides such as 3-phospholene isomers thereof, and the like can be mentioned.

  As an oxazoline type hydrolysis inhibitor, for example, 2,2'-o-phenylene bis (2-oxazoline), 2,2'-m-phenylene bis (2-oxazoline), 2,2'-p-phenylene bis (2-oxazoline), 2,2'-p-phenylenebis (4-methyl-2-oxazoline), 2,2'-m-phenylenebis (4-methyl-2-oxazoline), 2,2'-p -Phenylene bis (4,4'- dimethyl -2- oxazoline), 2, 2 'm- phenylene bis (4, 4'-dimethyl -2- oxazo line), 2, 2'- ethylene bis (2- oxazo line) 2,2'-Tetramethylene bis (2-oxazoline), 2,2'-hexamethylene bis (2-oxazoline), 2,2'-octamethylene bis (2-oxazoline), 2,2'-ether Examples include thylene bis (4-methyl-2-oxazoline), 2,2'-diphenylene bis (2-oxazoline) and the like.

  Examples of epoxy hydrolyzing agents include diglycidyl ethers of aliphatic diols such as 1,6-hexanediol, neopentyl glycol, and polyalkylene glycol; sorbitol, sorbitan, polyglycerol, pentaerythritol, diglycerol, glycerol, And polyglycidyl ethers of aliphatic polyols such as trimethylolpropane; polyglycidyl ethers of alicyclic polyols such as cyclohexanedimethanol; terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, trimellitic acid, adipic acid, sebacic acid and the like Diglycidyl esters or polyglycidyl esters of aliphatic or aromatic polyvalent carboxylic acids; resorcinol, bis- (p-hydroxyphenyl) methane, 2,2-bis- (p-hy) Diglycidyl ethers or polyglycidyl ethers of polyhydric phenols such as roxyphenyl) propane, tris- (p-hydroxyphenyl) methane, and 1,1,2,2-tetrakis (p-hydroxyphenyl) ethane; N-glycidyl derivatives of amines such as diglycidyl aniline, N, N-diglycidyl toluidine, and N, N, N ', N'-tetraglycidyl-bis- (p-aminophenyl) methane; triglycidyl derivatives of aminophenols And triglycidyl tris (2-hydroxyethyl) isocyanurate; and triglycidyl isocyanurate; and epoxy resins such as ortho cresol type epoxy resin and phenol novolac type epoxy resin.

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

<Antioxidant>
Antioxidants include radical scavengers and peroxide decomposers. Examples of the radical scavenger include phenolic compounds and amine compounds. Examples of peroxide decomposition agents include sulfur compounds and phosphorus compounds.

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

  Examples of sulfur-based antioxidants include dilauryl 3,3'-thiodipropionate, dimyristyl 3,3'-thiodipropionate, and distearyl 3,3'-thiodipropionate.

  Examples of phosphorus compounds include triphenyl phosphite, diphenyl isodecyl phosphite, 4,4'-butylidene-bis (3-methyl-6-tert-butylphenyl ditridecyl) phosphite, cyclic neopentanetetrayl Bis (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 -Desiloxy- 10-Dihydro-9-oxa-10-phosphaphenanthrene, tris (2,4-di-tert-butylphenyl) phosphite, cyclic neopentanetetrayl bis (2,4-di-tert-butylphenyl) Phosphite, cyclic neopentanetetrayl bis (2,6-di-tert-butyl-4-methylphenyl) phosphite, and 2,2-methylene bis (4,6-di-tert-butylphenyl) octyl phosphite Etc.

The thermal deterioration of the active hydrogen group-containing compound (H) can be prevented by using the antioxidant.
The addition amount of the antioxidant is not particularly limited, and is preferably 0.01 to 5 parts by mass, more preferably 0.1 to 3 parts by mass, particularly preferably 100 parts by mass of the active hydrogen group-containing compound (H). Is 0.2 to 2 parts by mass.

  As the antioxidant, it is preferable to use one or more kinds of phenol compounds which are radical scavengers from the viewpoint of stability and the antioxidant effect, and it is preferable to use one or more kinds of phenol compounds and peroxide decomposition agents which are radical scavengers. It is more preferable to use one or more phosphorus compounds in combination. In addition, it is particularly preferable to use, as an antioxidant, a phenol-based compound which is a radical scavenger and a phosphorus-based compound which is a peroxide decomposition agent in combination, and to use these antioxidants and the above-mentioned hydrolysis resistance together. .

<UV absorber>
Examples of the ultraviolet absorber include benzophenone compounds, benzotriazole compounds, salicylic acid compounds, oxalic acid anilide compounds, cyanoacrylate compounds, and triazine compounds.
The addition amount of the ultraviolet absorber is not particularly limited, and is preferably 0.01 to 3 parts by mass, more preferably 0.1 to 2.5 parts by mass with respect to 100 parts by mass of the active hydrogen group-containing compound (H). Particularly preferably, it is 0.2 to 2 parts by mass.

<Light stabilizer>
Examples of light stabilizers include hindered amine compounds and hindered piperidine compounds. The addition amount of the light stabilizer is not particularly limited, and is preferably 0.01 to 2 parts by mass, more preferably 0.1 to 1.5 parts by mass, with respect to 100 parts by mass of the active hydrogen group-containing compound (H). Particularly preferably, it is 0.2 to 1 part by mass.

(Antistatic agent (AS agent))
The pressure-sensitive adhesive of the present invention optionally contains one or more antistatic agents (AS agent) (but excluding those corresponding to the active hydrogen group-containing compound (H) and the surfactant (S)). Can. The antistatic agent may, for example, be an inorganic salt, an ionic liquid, an ionic solid, or a surfactant. Among these, an ionic liquid and an ionic solid are preferable. The “ionic liquid” is also referred to as a normal temperature molten salt, and is a salt having fluidity at 25 ° C.

  As the inorganic salt, for example, sodium chloride, potassium chloride, lithium chloride, lithium perchlorate, ammonium chloride, potassium chlorate, aluminum chloride, copper chloride, ferrous chloride, ferric chloride, ferric chloride, ammonium sulfate, potassium nitrate, sodium nitrate Sodium carbonate, sodium thiocyanate and the like.

  As an ionic liquid containing an imidazolium ion, for example, 1-ethyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide, 1,3-dimethylimidazolium bis (trifluoromethylsulfonyl) imide, and 1-butyl -3- methyl imidazolium bis (trifluoromethyl sulfonyl) imide etc. are mentioned.

  As an ionic liquid containing a pyridinium ion, for example, 1-methyl pyridinium bis (trifluoromethyl sulfonyl) imide, 1-butyl pyridinium bis (trifluoromethyl sulfonyl) imide, 1-hexyl pyridinium bis (trifluoromethyl sulfonyl) 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-methyl-pyridinium bis (perfluorobutylsulfonyl) imide, and the like.

  As an ionic liquid containing ammonium ion, for example, 1-butyl-3-methylpyridinium bis (trifluoromethanesulfonyl) imide, trimethylheptyl ammonium bis (trifluoromethanesulfonyl) imide, N, N-diethyl-N-methyl-N- Propylammonium bis (trifluoromethanesulfonyl) imide, N, N-diethyl-N-methyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide, N, N-diethyl-N-methyl-N-heptylammonium bis (trifluoromethane) And sulfonyl) imide, and tri-n-butyl methyl ammonium bis trifluoromethane sulfone imide and the like.

  In addition, commercially available ionic liquids such as pyrrolidinium salts, phosphonium salts, and sulfonium salts can be appropriately used.

  The ionic solid, like the ionic liquid, is a salt of a cation and an anion, but is a substance exhibiting a solid property at 25 ° C. under normal pressure. As a cation, an alkali metal ion, a phosphonium ion, a pyridinium ion, an ammonium ion etc. are preferable, for example.

  As an ionic solid containing an alkali metal ion, for example, lithium bisfluorosulfonyl imide, lithium bis trifluoromethyl sulfonyl imide, lithium bis pentafluoro ethyl sulfonyl imide, lithium bis hepta fluoro propyl sulfonyl imide, lithium bis nonane fluoro butyl sulfonyl imide, sodium bis Fluorosulfonyl imide, sodium bis trifluoromethyl sulfonyl imide, sodium bis penta fluoro ethyl sulfonyl imide, sodium bis hepta fluoro propyl sulfonyl imide, sodium bis nonane fluoro butyl sulfonyl imide, potassium bis fluoro sulfonyl imide, potassium bis trifluoromethyl sulfonyl imide, potassium bis Pentafluoroethylsulfonyl De, potassium bis heptafluoropropyl imide and potassium bis nonane-fluoro-butyl imide, and the like.

  Examples of ionic solid containing phosphonium ion include tetrabutylphosphonium bisfluorosulfonyl imide, tetrabutyl phosphonium bis trifluoromethyl sulfonyl imide, tetrabutyl phosphonium bis pentafluoroethyl sulfonyl imide, tetrabutyl phosphonium bis heptafluoropropyl sulfonylimide, tetrabutyl phosphonium Bisnonane fluorobutyl sulfonyl imide, tributyl hexadecyl phosphonium bis fluorosulfonyl imide, tributyl hexadecyl phosphonium bis trifluoromethyl sulfonyl imide, tributyl hexadecyl phosphonium bis pentafluoroethyl sulfonyl imide, tributyl hexadecyl phosphonium bis hepta fluoropropyl sulfonyl imide, trib Hexadecylphosphonium bisnonane fluorobutyl sulfonyl imide, tetraoctyl phosphonium bis fluoro sulfonyl imide, tetra octyl phosphonium bis trifluoromethyl sulfonyl imide, tetra octyl phosphonium bis pentafluoro ethyl sulfonyl imide, tetra octyl phosphonium bis hepta fluoro propyl sulfonyl imide, and The octyl phosphonium bis nonane fluoro butyl sulfonyl imide etc. are mentioned.

  As an ionic solid containing a pyridinium ion, for example, 1-hexadecyl-4-methylpyridinium bisfluorosulfonylimide, 1-hexadecyl-4-methylpyridinium bistrifluoromethylsulfonylimide, 1-hexadecyl-4-methylpyridinium bispentafluoroethylsulfonyl Imide, 1-hexadecyl-4-methylpyridinium bisheptafluoropropylsulfonyl imide, 1-hexadecyl-4-methylpyridinium bisnonane fluorobutyl sulfonylimide, etc. may be mentioned.

  As an ionic solid containing ammonium ion, for example, lauryl trimethyl ammonium chloride, tributyl methyl bis trifluoromethyl sulfonyl imide, tri butyl methyl bis penta fluoro ethyl sulfonyl imide, tri butyl methyl bis hepta fluoro propyl sulfonyl imido, tri butyl methyl bis nonane fluoro butyl sulfonyl imido , Octyl tributyl bis trifluoromethyl sulfonyl imide, octyl tri butyl bis penta fluoro ethyl sulfonyl imide, octyl tri butyl bis hepta fluoro propyl sulfonyl imido, octyl tri butyl bis bis nonane fluoro butyl sulfonyl imido, tetrabutyl bis fluoro sulfonyl imide, tetra butyl bis trifluoromethyl sulfonyl sulfonyl Imide, teto Butyl bis pentafluoroethylsulfonyl imide, tetrabutyl bis heptafluoropropylsulfonyl imide, and tetrabutyl arm bis nonane-fluoro-butyl imide and the like.

  In addition, well-known ionic solid whose cation is pyrrolidinium ion, imidazolium ion, sulfonium ion etc. can be used suitably.

  Surfactants other than surfactant (S) include nonionic surfactants and anionic surfactants, and both types are classified into low molecular weight surfactants and high molecular weight surfactants. .

Examples of nonionic low molecular weight surfactants include glycerin fatty acid ester, polyoxyalkylene alkyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene alkylamine, polyoxyethylene alkylamine fatty acid ester, fatty acid diethanolamide, etc. Be
Examples of anionic low molecular weight surfactants include alkyl sulfonates, alkyl benzene sulfonates, and alkyl phosphates.
Examples of amphoteric low molecular weight surfactants include alkyl betaines and alkyl imidazolium betaines.

Examples of the nonionic high molecular weight surfactant include polyether ester amide type, ethylene oxide-epichlorohydrin type, and polyether ester type.
Polystyrene sulfonic acid type etc. are mentioned as anionic high molecular surfactant.
Examples of amphoteric high molecular weight surfactants include amino acid type amphoteric surfactants such as higher alkyl amino propionates, higher alkyl dimethyl betaines, and betaine type amphoteric surfactants such as higher alkyl dihydroxyethyl betaines.

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

(Leveling agent)
The pressure-sensitive adhesive of the present invention can optionally contain a leveling agent. By adding a leveling agent, the leveling property of the adhesive layer can be improved. As a leveling agent, an acrylic type leveling agent etc. are preferable from a viewpoint of the adherend contamination control after pressure sensitive adhesive sheet re-peeling which an acrylic type leveling agent, a fluorine type leveling agent, a silicone type leveling agent, etc. are mentioned.

  The addition amount of the leveling agent is not particularly limited, and is preferably 100 parts by mass of the active hydrogen group-containing compound (H) from the viewpoint of suppression of adherend contamination after re-peeling of the pressure-sensitive adhesive sheet and improvement of the leveling property of the pressure-sensitive adhesive layer. The amount is 0.001 to 2 parts by mass, more preferably 0.01 to 1.5 parts by mass, and particularly preferably 0.1 to 1 parts by mass.

(Other optional ingredients)
The pressure-sensitive adhesive of the present invention can contain other optional components as needed, as long as the effects of the present invention are not impaired. Other optional components include catalysts, resins other than urethane resins, fillers (talc, calcium carbonate, titanium oxide, etc.), metal powders, colorants (pigments, etc.), foils, softeners, electrical conductivity Agents, silane coupling agents, lubricants, corrosion inhibitors, heat resistance stabilizers, weathering stabilizers, polymerization inhibitors, antifoam agents, and the like.
When the adhesive of the present invention contains a catalyst, it is preferable to add a known catalyst inhibitor such as acetylacetone for the purpose of improving the pot life of the adhesive.

(Blending ratio)
The pressure-sensitive adhesive of the present invention comprises at least one active hydrogen group-containing compound (H) (preferably a hydroxyl terminated urethane prepolymer (UPH)), at least one polyfunctional isocyanate compound (I), and a cationic hydrophilic group The surfactant (S) is included as an essential component, and, if necessary, one or more optional components. The blending ratio is not particularly limited, but the preferred blending ratio is as follows.
The amount of the one or more polyfunctional isocyanate compounds (I) relative to 100 parts by mass of the one or more active hydrogen group-containing compounds (H) is preferably 1 to 30 parts by mass, more preferably 3 to 20 parts by mass. If the amount of one or more polyfunctional isocyanate compounds (I) is 1 part by mass or more, the cohesion of the adhesive layer is good, and if it is 30 parts by mass or less, the pot life is good.

One or more active hydrogens are effectively exhibited because the above-mentioned effects (in particular, the reduction of the adhesive strength of the adhesive layer under the (moist) heat environment and the improvement of the removability and the reduction of the contamination of the adherend) are effectively exhibited. The amount of one or more surfactants (S) relative to 100 parts by mass of the group-containing compound (H) is 0.01 to 20 parts by mass, preferably 0.1 to 10 parts by mass, more preferably 0.2 to 5. It is 0 mass part.
If the amount of surfactant (S) added is too small, the effects of the addition may not be effectively exhibited. When the addition amount of the surfactant (S) is excessive, there is a possibility that the contamination of the adherend may occur due to the bleed out of the surfactant (S) when exposed to the (wet) heat environment.

(Method of producing adhesive)
The method for producing the pressure-sensitive adhesive of the present invention is not particularly limited.
One or more polyfunctional isocyanate compounds (I), one or more, relative to one or more active hydrogen group-containing compounds (H) (preferably, a hydroxyl terminated urethane prepolymer (UPH) synthesized by the above method) The pressure-sensitive adhesive of the present invention can be produced by adding and mixing the surfactant (S) of the above and optionally one or more optional components.

  The pressure-sensitive adhesive preferably has a gel fraction after curing of 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 cohesion of the adhesive layer becomes good, and good adhesion and removability can be obtained even after being exposed to a (wet) heat environment, and the bleed out component As a result, the contamination of the adherend can be reduced. In addition, a gel fraction can be calculated | required by the method as described in the term of [Example].

[Adhesive sheet]
The pressure-sensitive adhesive sheet of the present invention comprises a substrate sheet and a pressure-sensitive adhesive layer comprising a cured product of the above-mentioned pressure-sensitive adhesive of the present invention. The adhesive layer can be formed on one side or both sides of the substrate sheet. If necessary, the exposed surface of the adhesive layer can be coated with a release sheet. In addition, a peeling sheet is peeled when sticking an adhesive sheet to a to-be-adhered body.

In FIG. 1, the schematic cross section of the adhesive sheet of 1st Embodiment which concerns on this invention is shown. In FIG. 1, reference numeral 10 denotes a pressure-sensitive adhesive sheet, reference numeral 11 denotes a base sheet, reference numeral 12 denotes a pressure-sensitive adhesive layer, and reference numeral 13 denotes a release sheet. The adhesive sheet 10 is a single-sided adhesive sheet in which an adhesive layer is formed on one side of a substrate sheet.
FIG. 2 shows a schematic cross-sectional view of a pressure-sensitive adhesive sheet according to a second embodiment of the present invention. In FIG. 2, reference numeral 20 denotes a pressure-sensitive adhesive sheet, reference numeral 21 denotes a base sheet, reference numerals 22A and 22B denote a pressure-sensitive adhesive layer, and reference numerals 23A and 23B denote a release sheet.

  It does not restrict | limit especially as a base material sheet, A resin sheet, paper, and metal foil etc. are mentioned. The substrate sheet may be a laminated sheet in which any one or more layers are laminated on at least one surface of these substrate sheets. The surface on which the adhesive layer of the base sheet is to be formed may be subjected to an adhesion-promoting treatment such as corona discharge treatment and anchor coating agent application, as necessary.

The constituent resin of the resin sheet is not particularly limited, and ester resins such as polyethylene terephthalate (PET); olefin resins such as polyethylene (PE) and polypropylene (PP); vinyl resins such as polyvinyl chloride; nylon 66 etc. Amide-based resins; urethane-based resins (including foams); combinations thereof, and the like.
The thickness of the resin sheet excluding the polyurethane sheet is not particularly limited, and is preferably 15 to 300 μm. The thickness of the polyurethane sheet (including foam) is not particularly limited, and is preferably 20 to 50,000 μm.

The paper is not particularly limited, and examples thereof include plain paper, coated paper, and art paper.
It does not restrict | limit especially as a component metal of metal foil, Aluminum, copper, and these combination etc. are mentioned.

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

The pressure-sensitive adhesive sheet can be produced by a known method.
First, the pressure-sensitive adhesive of the present invention is coated on the surface of a substrate sheet to form a coated layer comprising the pressure-sensitive adhesive of the present invention. The coating method can apply a well-known method, and the roll coater method, the comma coater method, the die coater method, the reverse coater method, the silk screen method, the gravure coater method etc. are mentioned.
Next, the coated layer is dried and cured to form a pressure-sensitive adhesive layer comprising a cured product of the pressure-sensitive adhesive of the present invention. The heating and drying temperature is not particularly limited, and preferably about 60 to 150 ° C. The thickness (thickness after drying) of the adhesive layer varies depending on the application, but is preferably 0.1 to 200 μm.
Next, if necessary, a release sheet is attached to the exposed surface of the adhesive layer by a known method.
A single-sided pressure-sensitive adhesive sheet can be produced as described above.
By performing the above operation on both sides, a double-sided pressure-sensitive adhesive sheet can be manufactured.

  Contrary to the above method, the pressure-sensitive adhesive of the present invention is applied to the surface of the release sheet to form a coated layer comprising the pressure-sensitive adhesive of the present invention, and then the coated layer is dried and cured. The pressure-sensitive adhesive layer may be formed of a cured product of the pressure-sensitive adhesive, and the base sheet may be laminated on the exposed surface of the pressure-sensitive adhesive layer.

  The method for producing the pressure-sensitive adhesive sheet preferably includes a step of applying a pressure-sensitive adhesive on a substrate sheet, and heating the formed coating layer to form a pressure-sensitive adhesive layer including a cured product of the pressure-sensitive adhesive. The process includes a winding process of winding the obtained pressure-sensitive adhesive sheet around a core to form a pressure-sensitive adhesive sheet roll, and a curing process of curing the pressure-sensitive adhesive sheet roll.

As described above, according to the present invention, the initial curing property is good, and the adhesive force is reduced both in the initial stage (before time-lapse) and after time-lapse (particularly after time-lapse (especially after (wet) heat)). It is possible to provide a pressure-sensitive adhesive that is peelable and can form a pressure-sensitive adhesive layer that is less likely to cause contamination of the adherend after re-peeling, and a pressure-sensitive adhesive sheet using the same.
According to the present invention, even when placed in a (humid) thermal environment, the increase in adhesion is suppressed, and the adhesive layer having good removability and less adherent contamination after re-peeling is formed. An adhesive that can be used, and an adhesive sheet using the same can be provided.

[Use]
The pressure-sensitive adhesive sheet of the present invention can be used in the form of a tape, a label, a seal, a double-sided tape and the like. The pressure-sensitive adhesive sheet of the present invention is suitably 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 combining such flat panel displays and touch panels are used in TVs (TVs), personal computers (PCs), mobile phones, And widely used in electronic devices such as portable information terminals.
The pressure-sensitive adhesive sheet of the present invention includes flat panel displays and touch panel displays (collectively referred to simply as "displays"), and substrates manufactured or used in these manufacturing processes (glass substrates, and ITO on glass substrates) It is suitably used as a surface protective sheet of an ITO / glass substrate or the like on which an (indium tin oxide) film is formed and an optical member.

  Hereinafter, synthesis examples, examples according to the present invention, and comparative examples will be described. In the following description, “parts” means parts by mass, “%” means 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 gel permeation chromatography (GPC). The measurement conditions were as follows. In addition, both Mn and Mw are polystyrene conversion values.
<Measurement conditions>
Device: SHIMADZU Prominence (manufactured by Shimadzu Corporation),
Column: Two LF-804 manufactured by Shodex Corporation are connected in series,
Detector: Differential Refractive Index Detector (RID-10A),
Solvent: tetrahydrofuran (THF),
Flow rate: 1 mL / min,
Solvent temperature: 40 ° C,
Sample concentration: 0.2%
Sample injection volume: 100 μL.

[material]
The materials used are as follows.
(Active hydrogen group-containing compound (HX))
<Polyol of relatively high molecular weight> 100 Mn>
(HX-11): Kuraray polyol P-1010, manufactured by Kuraray Co., Ltd., bifunctional polyester polyol, hydroxyl value 112.2,
(HX-12): PEG 400, manufactured by Sanyo Chemical Industries, Ltd., bifunctional polyether polyol, hydroxyl value 280.5,
(HX-13): Sannix PP-2000, manufactured by Sanyo Chemical Industries, Ltd., bifunctional polypropylene glycol, hydroxyl value 56.1,
(HX-14): Preminol 5001F, manufactured by Asahi Glass Co., Ltd., bifunctional polyether polyol, hydroxyl value 28.1, degree of unsaturation 0.02,
(HX-15): GL 3000, manufactured by Sanyo Chemical Industries, Ltd., trifunctional polyether polyol, hydroxyl value 56.1,
(HX-16): GP 3000, manufactured by Sanyo Chemical Industries, Ltd., trifunctional polyether polyol, hydroxyl value 56.1,
(HX-17): Exenol 851, manufactured by Asahi Glass Co., Ltd., trifunctional polyether polyol, hydroxyl value 25.1, degree of unsaturation 0.04.
(HX-18): Preminol 7012, manufactured by Asahi Glass Co., Ltd., trifunctional polyether polyol, hydroxyl value 16.8, degree of unsaturation 0.02.
The unit of degree of unsaturation is meq / g.

<Polyamine>
(HX-21): IPDA, isophorone diamine, manufactured by EVONIK, bifunctional polyamine.
<Amino alcohol>
(HX-22): AMP, 2-amino-2-methyl-1-propanol, bifunctional amino alcohol.
<Lower molecular weight polyol less than 100 Mn>
(HX-31): 1,3 PDO, 1,3-propanediol, bifunctional polyol.
The number of functional groups, Mn, and Mn per functional group of each active hydrogen group-containing compound (HX) are shown in Tables 2-1 and 2-2. As for polyols, the series of terminal hydroxyl groups (terminal OH) is also shown in the same table.

(Polyisocyanate (N))
(N-11): HDI, hexamethylene diisocyanate, manufactured by Sumika Kobethurourethane, 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)), Tosoh Co., Coronate T-80 ,
(N-13): IPDI, isophorone diisocyanate, manufactured by Sumika Kobethurourethane, 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.

(Multifunctional isocyanate compound (I))
(I-11) HDI adduct, Coronate HL, manufactured by Tosoh Corporation, hexamethylene diisocyanate (HDI) / trimethylolpropane (TMP) adduct,
(I-12) HDI nurate, Sumidur N-3300, manufactured by Sumika Bayer Urethane Co., Ltd., hexamethylene diisocyanate (HDI) / isocyanurate.

(Surfactant having a cationic hydrophilic group (S), other surfactant (R))
A list of surfactants (S) having a cationic hydrophilic group and other surfactants (R) used is shown in Table 1. In the table, the amine value and the acid value are non-volatiles equivalent values (unit: mg KOH / g).

(Plasticizer (P))
(P-11): Excepearl MOL, methyl oleate, manufactured by Kao Corporation,
(P-12): Monosizer W262, polyether ester plasticizer, manufactured by DIC.
(Antioxidant (C))
(C-11): IRGANOX 1010, pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], a phenolic antioxidant, manufactured by BASF.

[Synthesis Example of Solution of Hydroxyl-Terminated Urethane Prepolymer (UPH)]
Synthesis Example 1 (One-Step Polymerization Method)
In a four-necked flask equipped with a stirrer, a reflux condenser, a nitrogen introduction tube, a thermometer, and a dropping funnel, 5 parts by mass of an active hydrogen group-containing compound (HX-11), an active hydrogen group-containing compound (HX-18) 95 parts by mass, 1.6 parts by mass of 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 mixed and mixed. The contents were gradually heated to 75 ° C. and allowed to react for 3 hours.
The ratio of the number of moles of isocyanate groups possessed by the polyisocyanate (N) used in the reaction to the total number of moles of active hydrogen groups possessed by all the active hydrogen group-containing compounds (HX) used in the reaction (NCO / H ratio) is It was 0.49.
After confirming the disappearance of the remaining isocyanate group by infrared spectroscopy (IR analysis), the content liquid was cooled to 30 ° C. to complete the reaction. Finally, 0.56 parts by mass of acetylacetone was added.
As described above, a solution of a non-volatile component 60%, a viscosity of 2,100 cps, and a colorless and transparent hydroxyl-terminated urethane prepolymer (UPH-1) was obtained. The obtained hydroxyl group-terminated urethane prepolymer had a Mw of 105,000.
The compounding composition, the NCO / H ratio, and the Mw of the obtained hydroxyl group-terminated urethane prepolymer are shown in Table 2-1.

Synthesis Examples 2 to 12 (One-Step Polymerization Method)
In Synthesis Examples 2 to 12, in the same manner as in Synthesis Example 1 except that the type of the active hydrogen group-containing compound (HX), the type of the polyisocyanate (N), and the compounding ratio thereof are changed, Thus, a solution of colorless and transparent hydroxyl-terminated urethane prepolymers (UPH-2) to (UPH-11) was obtained.
In each synthesis example, the compounding composition, the NCO / H ratio, and the Mw of the obtained hydroxyl group-terminated urethane prepolymer are shown in Tables 2-1 and 2-2.

Synthesis Example 13 (Multi-step polymerization method)
100 parts by mass of active hydrogen group-containing compound (HX-13) and 17 parts by mass of polyisocyanate (N-13) in a 4-neck flask equipped with a stirrer, a reflux condenser, a nitrogen introduction pipe, a thermometer, and a dropping funnel Then, 29.3 parts by mass of toluene and 0.01 parts by mass of dioctyltin dilaurate as a catalyst were charged and mixed. The content liquid was gradually heated up to 100 ° C. and reacted for 2 hours. Then, it cooled to 25 degreeC and added 90.7 mass parts of ethyl acetate, and 0.5 mass part of acetylacetone, Then, 3.4 mass parts of active hydrogen group containing compounds (HX-21) were dripped over 1 hour. The solution temperature was maintained at 25 ° C. and the reaction was continued for further 1 hour, and then 1.2 parts by mass of an active hydrogen group-containing compound (HX-22) was added for reaction. The reaction was terminated after confirming the disappearance of the residual isocyanate group by infrared spectroscopy (IR analysis).
As described above, a solution of a non-volatile content of 45%, a viscosity of 3,100 cps, and a colorless and transparent hydroxyl-terminated urethane prepolymer (UPH-12) was obtained. The obtained hydroxyl group-terminated urethane prepolymer had Mw = 52,000.
The compounding composition, the NCO / H ratio, and the Mw of the obtained hydroxyl group-terminated urethane prepolymer are shown in Table 2-2.

Synthesis Example 14 (Multi-step polymerization method)
In a four-necked flask equipped with a stirrer, a reflux condenser, a nitrogen inlet, a thermometer, and a dropping funnel, 100 parts by mass of an active hydrogen group-containing compound (HX-18), and polyisocyanate (N-13) 6.5 A mass part, 45.7 mass parts of toluene, and 0.02 mass part of dioctyl tin dilaurate as a catalyst were charged and mixed. The content liquid was gradually heated to 80 ° C., and reacted for 2 hours to obtain an isocyanate group-terminated prepolymer. Then, after cooling to 60 degreeC and adding 26.6 mass parts of ethyl acetate, 2.5 mass parts of active hydrogen group containing compounds (HX-31) were added, and it was made to react. After confirming the disappearance of the remaining isocyanate group by infrared spectroscopy (IR analysis), the content liquid was cooled to 30 ° C. to complete the reaction. Finally, 0.43 parts by mass of acetylacetone was added.
As described above, a solution of a colorless and hydroxyl-terminated urethane prepolymer (UPH-13) having a nonvolatile content of 60% and a viscosity of 2,800 cps was obtained. The obtained hydroxyl group-terminated urethane prepolymer had a Mw of 98,000.
The compounding composition, the NCO / H ratio, and the Mw of the obtained hydroxyl group-terminated urethane prepolymer are shown in Table 2-2.

[Manufacture of urethane pressure sensitive adhesive and adhesive sheet]
Example 1
100 parts by mass (in terms of non-volatile components) of a hydroxyl-terminated urethane prepolymer (UPH-1) solution obtained in Synthesis Example 1 (in terms of nonvolatile content), 10 parts by mass of polyfunctional isocyanate compound (I-11), surfactant having a cationic hydrophilic group ( S-11) A urethane-based pressure-sensitive adhesive was obtained by blending 0.5 parts by mass of an antioxidant (C-1) and 100 parts by mass of ethyl acetate as a solvent and stirring with a disper . In addition, the usage-amount of each material other than a solvent shows the non-volatile-content conversion value (the same may be said of another Example and a comparative example). The composition is shown in Table 3-1.
As a substrate sheet, a 50 μm thick polyethylene terephthalate (PET) film (Lumirror T-60, manufactured by Toray Industries, Inc.) was prepared. Using a comma coater (registered trademark), the obtained urethane-based pressure-sensitive adhesive was coated on one side of this base sheet so that the thickness after drying would be 12 μm. Next, the formed coating layer was dried at 100 ° C. for 2 minutes to form an adhesive layer. On this adhesive layer, a 38 μm-thick release sheet (Superstick SP-PET 38, manufactured by Lintec Corporation) was adhered to obtain an adhesive sheet.
Evaluation of the initial curing was carried out after curing for 5 hours under conditions of 23 ° C. and 50% RH. For other evaluations, after aging for 1 week under conditions of 23 ° C. and 50% RH, the evaluations were performed.

(Examples 2-42, Comparative Examples 1-5)
In each of Examples 2 to 42 and Comparative Examples 1 to 5, Example 1 and Example 1 were used except that the types and blending ratios of the materials used were changed as shown in Tables 3-1 to 3-6 and Table 4. In the same manner, production of urethane-based pressure-sensitive adhesives and pressure-sensitive adhesive sheets and their evaluation were carried out.

[Evaluation items and evaluation method]
Evaluation items and evaluation methods of the pressure-sensitive adhesive and the pressure-sensitive adhesive sheet are as follows.
(Gel fraction)
A test piece with a width of 30 mm and a length of 100 mm was cut out from the pressure-sensitive adhesive sheet after aging for 1 week in an atmosphere of 23 ° C. and 50% RH. The test piece was attached to a SUS mesh (opening: 0.077 mm, wire diameter: 0.05 mm), and then immersed in ethyl acetate. It extracted at 50 degreeC for 24 hours, Then, it dried at 100 degreeC for 30 minutes, and the gel fraction (mass%) after hardening was computed based on following formula (1).
Gel fraction (mass%) = (G2 / G1) × 100 (1)
In the above formulae, each symbol indicates the following parameter.
G1: Weight of adhesive layer before extraction with ethyl acetate,
G2: Weight of adhesive layer after extraction with ethyl acetate and drying.

(Initial cure)
A test piece with a width of 30 mm and a length of 100 mm was cut out from the pressure-sensitive adhesive sheet after aging for 5 hours under an atmosphere of 23 ° C. and 50% RH. The test piece was attached to a SUS mesh (opening: 0.077 mm, wire diameter: 0.05 mm), and then immersed in ethyl acetate. It extracted at 50 degreeC for 24 hours, Then, it dried at 100 degreeC for 30 minutes, and the initial stage gel fraction (mass%) was computed based on following formula (2).
Initial gel fraction (mass%) = (G4 / G3) × 100 (2)
In the above formulae, each symbol indicates the following parameter.
G3: Weight of adhesive layer before extraction with ethyl acetate,
G4: Weight of adhesive layer after extraction with ethyl acetate and drying.
Evaluation criteria are as follows.
◎: The initial gel fraction is 70% by mass or more, excellent.
○: The initial gel fraction is 40% by weight or more and less than 70% by weight, good.
Δ: Initial gel fraction is 20% by mass or more and less than 40% by mass, practicable.
X: Initial gel fraction less than 20% by mass, not practical.

(Adhesive force before heating)
The test piece of width 25 mm length 100 mm was cut out from the adhesive sheet after aging for 1 week in 23 degreeC-50% RH atmosphere. Then, the release sheet was peeled off from the test piece under an atmosphere of 23 ° C. and 50% RH, the exposed adhesive layer was attached to the surface of the caustic soda glass plate, and the 2 kg roll was reciprocated once for pressure bonding. Then, it was left to stand in an atmosphere of 23 ° C. and 50% RH for 24 hours. Subsequently, in accordance with JIS Z 0237, using a tensile tester (Tensilon: manufactured by ORIENTEC Co., Ltd.), the adhesive strength (adhesive strength before heating) was measured under the conditions of peeling speed 300 mm / min and peeling angle 180 °. Evaluation criteria are as follows.
◎: less than 20 mN / 25 mm, excellent.
○: 20 mN / 25 mm or more and less than 50 mN / 25 mm, good.
Fair: 50 mN / 25 mm or more and less than 200 mN / 25 mm, practical use possible.
×: 200 mN / 25 mm or more, not practical.

(Rise of adhesion after heating)
The test piece of width 25 mm length 100 mm was cut out from the adhesive sheet after aging for 1 week in 23 degreeC-50% RH atmosphere. Then, the release sheet was peeled off from the test piece under an atmosphere of 23 ° C. and 50% RH, the exposed adhesive layer was adhered to a caustic soda glass plate, and a 2 kg roll was reciprocated one time to be crimped. Then, it was left to stand in a 150 ° C. atmosphere for 1 hour. Next, after air cooling in an atmosphere of 23 ° C. and 50% RH for 30 minutes, a peeling speed of 300 mm / min and a peeling angle of 180 ° using a tensile tester (Tensilon: manufactured by Orientec Co., Ltd.) according to JIS Z0237. The adhesive force (adhesive force after heating at 150 ° C.) was measured. Based on following formula (3), the increase rate of the adhesive force after a heating was computed.
Increase rate of adhesion after heating (%) = (N2 / N1) × 100 (3)
In the above formulae, each symbol indicates the following parameter.
N1: adhesion value before heating measured in evaluation 2,
N2: Value of adhesion after 150 ° C. heating measured in Evaluation 3.
Evaluation criteria are as follows.
◎: less than 150%, excellent.
○: 150% or more and less than 300%, good.
Fair: 300% or more and less than 500%, practical use possible.
X: 500% or more, not practical.

(Adhesive substance contamination control ability)
Two test pieces of width 70 mm length 100 mm were cut out from the adhesive sheet after aging for 1 week in 23 degreeC-50% RH atmosphere. The release sheet was peeled off under an atmosphere of 23 ° C. and 50% RH for each test piece, and a caustic soda glass plate was attached to the surface of the exposed adhesive layer, and was pressure-bonded with a laminator. One of the obtained two laminates was left in an oven set at 60 ° C. and 90% RH for 72 hours. The other laminate was left in an oven set at 85 ° C.-85% RH for 24 hours. The laminates of the two sheets were taken out of the oven and air-cooled in an atmosphere of 23 ° C. and 50% RH for 3 hours, and then the pressure-sensitive adhesive sheet was peeled from the glass plate to evaluate adherend contamination. LED (light emitting diode) lamp light was irradiated to the surface of the glass plate of the side which stuck the adhesive sheet in the dark room, and it evaluated by visual observation. Evaluation criteria are as follows.
◎: No adhesion of the adhesive layer component is observed on the glass surface in any of the heating condition samples of 60 ° C.-90% RH and 85 ° C.-85% RH.
Good: No adhesion of the adhesive layer component is observed on the glass surface in the sample heated at 60 ° C.-90% RH, but thin in one to three places on the glass surface in the sample heated at 85 ° C.-85% RH Good adhesion of the adhesive layer component is observed.
Fair: adhesion of a thin adhesive layer component is observed at 1 to 3 locations on the glass surface in the sample heated at 60 ° C.-90% RH, and at 4 or more locations on the glass surface in the sample heated at 85 ° C.-85% RH Adhesion of a thin adhesive layer component is observed and / or adhesion of a thick adhesive layer component is observed at one or two places on the glass surface, which is practical.
X: adhesion of a thin adhesive layer component is observed at 4 or more locations on the glass surface in any of the heating conditions of 60 ° C.-90% RH and 85 ° C.-85% RH and / or 1 to 2 locations on the glass surface Thick adhesion layer components are observed, not practical.

[Evaluation results]
The evaluation results are shown in Tables 3-1 to 3-6 and Table 4.
In Examples 1 to 42,
At least one active hydrogen group-containing compound (H) having a plurality of active hydrogen groups in one molecule,
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 160 mg KOH / g in terms of nonvolatile content,
The urethane-type adhesive whose content of surfactant (S) is 0.01-20 mass parts with respect to 100 mass parts of active hydrogen group containing compounds (H) was manufactured.
In any of these examples, a pressure-sensitive adhesive having good initial curability can be produced, the adhesion before heating is small, the rate of increase in adhesion after heating at 150 ° C. is small, and exposure to a moist heat environment is possible. It was possible to produce a pressure-sensitive adhesive sheet with less contamination of the adherend.

  The pressure-sensitive 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 had a large increase in adhesion after heating and was defective. there were.

  The pressure-sensitive adhesive sheet obtained in Comparative Example 2 in which the addition amount of the surfactant (S) having a cationic hydrophilic group is more than 20 parts by mass with respect to 100 parts by mass of the active hydrogen group-containing compound (H) The adhesion before heating and the rate of increase in adhesion after heating were poor, and the contamination of the adherend was also remarkable.

  The pressure-sensitive adhesive sheet obtained in Comparative Example 3 to which a comparative surfactant (R) having a cationic hydrophilic group having an amine value of more than 160 mg KOH / g in terms of non-volatile content is added is 150 ° C. The rate of increase was large and bad.

  The pressure-sensitive adhesive sheet obtained in Comparative Examples 4 and 5 to which a comparative surfactant (R) having a cationic hydrophilic group having an amine value of less than 0.1 mg KOH / g in terms of nonvolatile content is added is heated at 150 ° C. The rate of increase in the adhesive strength was large, and the contamination of the adherend was also remarkable.

  The present invention is not limited to the above embodiments and examples, and design changes can be made as appropriate without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 10 and 20 Adhesive sheet 11, 21 Base material sheet 12, 22A, 22B Adhesive layer 13, 23A, 23B Peeling sheet

Claims (6)

At least one active hydrogen group-containing compound (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 0.1 to 150 mg KOH / g in terms of nonvolatile content,
The urethane type adhesive whose content of surfactant (S) is 0.01-20 mass parts with respect to 100 mass parts of active hydrogen group containing compounds (H).   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. Urethane adhesive.   The urethane-based pressure-sensitive adhesive according to claim 1 or 2, wherein the surfactant (S) has one hydrophilic group.   The urethane-based pressure-sensitive adhesive according to any one of claims 1 to 3, wherein the surfactant (S) has an amine value of 0.1 to 60 mg KOH / g in terms of nonvolatile content.   The urethane according to any one of claims 1 to 4, further comprising at least one alteration inhibitor selected from the group consisting of an antioxidant, a hydrolysis resistant agent, an ultraviolet light absorber, and a light stabilizer. Adhesives.   The adhesive sheet containing a base material sheet and the adhesion layer which consists of hardened | cured material of the adhesive in any one of Claims 1-5.

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