JP6645607B2 - Adhesive, adhesive sheet, and laminate - Google Patents

Description

  The present invention relates to an adhesive having antistatic properties.

  Display devices such as a liquid crystal display (LCD), a flat panel display (FPD) such as an organic electroluminescence (OLED), a touch panel display (TSP) combining a flat panel display and a touch panel, and the like include a television (TV), a personal computer ( PC), portable information terminals and the like.

  Conventionally, a surface protection sheet has been widely used to protect an optical member used in a display device from scratches, dust and the like.

  The pressure-sensitive adhesive containing a urethane resin (hereinafter, referred to as a urethane pressure-sensitive adhesive) has excellent adhesive strength and excellent removability to various adherends such as glass for the pressure-sensitive adhesive layer of the surface protection sheet. Used from. In addition, static electricity generated when the surface protection sheet is peeled off from the adherend may destroy electronic devices inside the FPD or TSP, so that antistatic performance may be required.

  Patent Document 1 contains a polyurethane resin (A) containing a hydroxyl group, a polyfunctional isocyanate compound (B), a compound (C) having a molecular weight of 250 to 1000 containing no hydroxyl group and isocyanate group, and an ionic compound (D), A urethane-based pressure-sensitive adhesive composition comprising 0.05 to 5 parts by weight of the component (D) based on 100 parts by weight of the total of the components (A) to (C) is disclosed.

  Patent Document 2 discloses a urethane-based pressure-sensitive adhesive containing a polyurethane-based resin, which is obtained by curing a composition containing a polyol (A) and a polyfunctional isocyanate compound (B). An equivalent ratio of NCO groups to OH groups in the polyol (A) and the polyfunctional isocyanate compound (B) is more than 1.0 and 5.0 or less as NCO groups / OH groups. A urethane-based pressure-sensitive adhesive is disclosed in which the urethane-based pressure-sensitive adhesive contains an ionic liquid containing a fluoroorganic anion.

JP 2017-105866 A JP-A-2005-098503

  However, the conventional pressure-sensitive adhesive provided the desired antistatic property by including the antistatic agent, but the metal catalyst in the pressure-sensitive adhesive coordinated with the antistatic agent, thereby reducing the reaction rate of the isocyanate curing agent. Therefore, the curing speed was reduced. In addition, if the surface protection sheet is manufactured by roll-to-roll instead of sheet-by-sheet, a step that occurs when the top of the surface protection sheet is attached to the winding roll of the coating device is added to the adhesive layer by the winding pressure, and the winding is performed. Since the influence of the step is left on the pressure-sensitive adhesive layer as an impression, the surface protection sheet needs to be discarded until the impression disappears. Further, the decrease in the curing speed due to the incorporation of the antistatic agent reduces the cohesive force of the pressure-sensitive adhesive layer immediately after coating, so that the sheet length until the indentation disappears increases and the yield of the surface protective sheet decreases. There was a problem. In addition, the decrease in the curing rate causes a decrease in the crosslinking density of the adhesive layer, and there is a problem in that the adhesive strength after aging at high temperature is increased and the removability is reduced. Further, since the pressure-sensitive adhesive of Patent Document 2 is manufactured by a so-called one-shot method without using urethane polyol, the cohesive force of the pressure-sensitive adhesive layer immediately after coating is low, and the yield is poor.

  An object of the present invention is to provide a pressure-sensitive adhesive which can form a pressure-sensitive adhesive layer which has a good yield and is hardly deteriorated in removability after storage at high temperature, and a pressure-sensitive adhesive sheet.

  In the present invention, the pressure-sensitive adhesive is a urethane polyol (A) having a weight average molecular weight of 100,000 to 500,000, which is a reaction product of the polyol (a) and the polyisocyanate (b), an isocyanate curing agent (B), an antioxidant ( D), an antistatic agent (E) and a polyfunctional polyol (F).

  According to the present invention described above, it is possible to provide a pressure-sensitive adhesive and a pressure-sensitive adhesive sheet that can form a pressure-sensitive adhesive layer that has a good yield and is hardly deteriorated in removability after high-temperature aging.

Before describing the present invention, terms are defined. In this specification, an adherend refers to a partner to which an adhesive tape is attached.
In this specification, the pressure-sensitive adhesive sheet includes a base material and a pressure-sensitive adhesive layer formed of a cured product of the pressure-sensitive adhesive of this specification.
As used herein, "tape", "film", and "sheet" have the same meaning.
In the present specification, the main component refers to a component having the largest blending amount among a plurality of blended components.

  In the present specification, unless otherwise specified, “molecular weight” means a number average molecular weight (Mn). “Mn” is a number average molecular weight in terms of polystyrene determined by gel permeation chromatography (GPC) measurement.

The pressure-sensitive adhesive of the present specification is a reaction product of a polyol (a) and a polyisocyanate (b), a urethane polyol (A) having a weight average molecular weight of 100,000 to 500,000, an isocyanate curing agent (B), and an antioxidant. (D), an antistatic agent (E) and a polyfunctional polyol (F).
The pressure-sensitive adhesive of the present specification preferably forms a pressure-sensitive adhesive layer by coating and is used as a pressure-sensitive adhesive sheet. The pressure-sensitive adhesive sheet preferably includes a substrate.

  The pressure-sensitive adhesive of the present specification has the disadvantage that the weight-average molecular weight of the urethane polyol (A) is set to be high and the combination of the polyfunctional polyol (F) and the curing speed caused by the compounding of the antistatic agent (E) is reduced. Can be counteracted, and the decrease in yield can be improved. Furthermore, the pressure-sensitive adhesive of the present specification contains an antioxidant (D), whereby a pressure-sensitive adhesive layer whose removability is hardly reduced after aging at high temperature can be obtained.

The pressure-sensitive adhesive of the present specification can be used for, for example, a liquid crystal display (LCD) having a flat portion or a curved surface portion, a display such as an organic electroluminescence (OLED), and a touch panel using such a display. Further, it can be widely used for surface protection of electronic devices such as mobile phones, smartphones, tablet terminals, and computers equipped with such displays or touch panels.
Further, the material of the adherend is not limited to glass, and can be used to protect easily fragile materials such as polyolefin, gold, silver, copper, and ITO.

The application of the pressure-sensitive adhesive is not limited to displays, but can be used for, for example, window glasses, LEDs, vehicles, wiring members, and laminates thereof.
Further, the pressure-sensitive adhesive sheet of the present specification can be used for protection during the manufacturing process of various members, and also for products after manufacturing. Needless to say, the pressure-sensitive adhesive of the present specification can be used for purposes other than surface protection.

(Urethane polyol (A))
The urethane polyol (A) is a reaction product obtained by subjecting one or more polyols (a) and one or more polyisocyanates (b) to a urethane reaction. The polyisocyanate (b) is preferably a bifunctional isocyanate (b1) having two isocyanate groups in one molecule (also referred to as diisocyanate). Further, the polyol (a) is preferably a polyol (a1) having two or more hydroxyl groups in one molecule. The isocyanate group (isocyanato group) of the polyisocyanate (b) is used in a molar ratio (NCO / OH ratio) that is smaller than the hydroxyl group of the polyol (a). Thereby, a urethane polyol having a hydroxyl group is obtained. In the urethane reaction, it is preferable to use a catalyst for promoting the reaction. A solvent can be used for the urethanization reaction, if necessary.
The urethane polyol (A) can be used alone or in combination of two or more.

<Polyol (a)>
The polyol (a) is a compound having two or more hydroxyl groups. The polyol (a) is preferably a polyol such as a polyether polyol, a polyester polyol, a polybutadiene-modified polyol, a polycarbonate polyol, or a castor oil polyol, and more preferably a polyether polyol, a polyester polyol, or a polybutadiene-modified polyol.
In the present specification, the polyol (a) may be of one type, but when two or more types are used in combination, the cohesive force and the adhesive force of the adhesive layer are easily adjusted. When one kind of the polyol (a) is used, it is preferable to use a polyol having three or more hydroxyl groups. When two or more polyols (a) are used, it is preferable to use a polyol having two hydroxyl groups and a polyol having three or more hydroxyl groups in combination. When a polyol having three or more hydroxyl groups is used in combination, the NCO / OH ratio (molar ratio) of the polyisocyanate (b) and the polyol (a) is preferably set to 0.80 or less. When the NCO / OH ratio (molar ratio) is used in an appropriate range, the reaction can be easily controlled in the synthesis of the urethane polyol (A).

  Examples of the polyether polyol include a reaction product obtained by addition-polymerizing one or more oxirane compounds using an active hydrogen-containing compound having two or more active hydrogens in one molecule as an initiator.

The active hydrogen-containing compound is preferably a hydroxyl group-containing compound, an amine or the like.
Examples of the hydroxyl group-containing compound include bifunctional active hydrogen-containing compounds such as ethylene glycol (EG), propylene glycol (PG), 1,4-butanediol, neopentyl glycol, and butylethylpentanediol; glycerin, trimethylolpropane, and the like. And a tetrafunctional active hydrogen-containing compound such as pentaerythritol.
Examples of the amine include bifunctional active hydrogen-containing compounds such as N-aminoethylethanolamine, isophoronediamine, and xylylenediamine; trifunctional active hydrogen-containing compounds such as triethanolamine; tetrafunctional active hydrogen such as ethylenediamine and aromatic diamine. Compounds containing: pentafunctional active hydrogen-containing compounds such as diethylenetriamine.

  Examples of the oxirane compound include an alkylene oxide (AO) such as ethylene oxide (EO), propylene oxide (PO), and butylene oxide (BO); and tetrahydrofuran (THF).

  The polyether polyol preferably has an alkyleneoxy group derived from an active hydrogen-containing compound in the molecule (this polyol is also referred to as “polyoxyalkylene polyol”). As the hydroxyl group-containing compound constituting the polyoxyalkylene polyol, polyether polyols such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol are preferable, and particularly, polypropylene glycol having low crystallinity and easily exhibiting flexibility is preferable.

  The number average molecular weight (Mn) of the polyether polyol is not particularly limited, but is preferably 200 to 6,000, more preferably 400 to 5,000, and more preferably 400 to 5,000 because transparency and flexibility are easily developed. 000 is more preferred. By controlling Mn to 200 or more, it is easy to control the reaction during the synthesis of the urethane polyol (A). Further, by setting Mn to 6,000 or less, it is easy to adjust the cohesive force of the urethane polyol (A) to an appropriate range.

  The polyester polyol is, for example, a compound (esterified product) obtained by an esterification reaction of one or more polyol components and one or more acid components, or a compound (ring-opened polymer) synthesized by ring-opening polymerization of lactone. preferable.

  Examples of the lactone include polycaprolactone, poly (β-methyl-γ-valerolactone), and polyvalerolactone.

  The polyol component is, for example, diethylene glycol, 1,3-butanediol, 3-methyl-1,5-pentanediol, 2-butyl-2-ethyl-1,3-propanediol, in addition to the above active hydrogen-containing compound. , 2,4-diethyl-1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 2-ethyl-1,3-hexanediol, 1,8-octanediol, 1,9- Nonanediol, 2-methyl-1,8-octanediol, 1,8-decanediol, octadecanediol, hexanetriol and the like can be mentioned.

  Acid components include, for example, succinic acid, methyl succinic acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, 1,12-dodecandioic acid, 1,14-tetradecandioic acid, dimer acid, 2-methyl-1,4 -Cyclohexanedicarboxylic acid, 2-ethyl-1,4-cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, isophthalic acid, terephthalic acid, 1,4-naphthalenedicarboxylic acid, and 4,4′-biphenyldicarboxylic acid , Dimer acid, trimer acid, and acid anhydrides thereof.

  The number average molecular weight (Mn) of the polyester polyol is preferably from 200 to 6,000, more preferably from 500 to 6,000, further preferably from 500 to 4,000, and particularly preferably from 500 to 3,000. By controlling Mn to 200 or more, it is easy to control the reaction during the synthesis of the urethane polyol (A). Further, by setting Mn to 6,000 or less, it is easy to adjust the cohesive force of the urethane polyol (A) to an appropriate range.

  The polybutadiene-modified polyol has, for example, two or more hydroxyl terminal groups, a 1,2-vinyl site, a 1,4-cis site, a 1,4-trans site, or a hydrogenated structure thereof. It is a chain or branched polybutadiene.

  The number average molecular weight (Mn) of the polybutadiene-modified polyol is preferably from 200 to 6,000, more preferably from 500 to 6,000, further preferably from 500 to 4,000, and particularly preferably from 500 to 3,000. By controlling Mn to 200 or more, it is easy to control the reaction during the synthesis of the urethane polyol (A). Further, by setting Mn to 6,000 or less, it is easy to adjust the cohesive force of the urethane polyol (A) to an appropriate range.

  The degree of hydrogenation of the polybutadiene-modified polyol is preferably such that all of the double bond sites existing before hydrogenation are hydrogenated, but in the present invention, some double bond sites remain. Is also good.

Other polyols other than the above include, for example, polycarbonate polyol, castor oil polyol and the like. Other polyols are preferably used in combination with a polyether polyol or a polyester polyol.
Other polyols have a number average molecular weight (Mn) of about 200 to 6,000.

  When the polyol (a) contains an acidic functional group such as a carboxyl group or a sulfo group, the adherend may be corroded. Therefore, it is preferable to use a polyol having no acidic functional group.

  Among them, the polyol (a) is preferably aliphatic. Thereby, the removability after the high temperature test is further improved, and the transparency of the adhesive layer is easily maintained.

<Polyisocyanate (b)>
As the polyisocyanate (b), for example, known polyisocyanates such as an aromatic polyisocyanate, an aliphatic polyisocyanate, an araliphatic polyisocyanate, and an alicyclic polyisocyanate can be used.

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

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

  As the araliphatic polyisocyanate, for example, ω, ω′-diisocyanate-1,3-dimethylbenzene, ω, ω′-diisocyanate-1,4-dimethylbenzene, ω, ω′-diisocyanate-1,4-diethylbenzene , 1,4-tetramethylxylylene diisocyanate, and 1,3-tetramethyl xylylene diisocyanate.

  Examples of the alicyclic polyisocyanate include 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate, 1,3-cyclopentane diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, and methyl-2. , 4-cyclohexanediisocyanate, methyl-2,6-cyclohexanediisocyanate, 4,4'-methylenebis (cyclohexylisocyanate), 1,4-bis (isocyanatomethyl) cyclohexane, 1,4-bis (isocyanatomethyl) cyclohexane and the like No.

  The above polyisocyanate is a diisocyanate, but a triisocyanate modified from the above diisocyanate can also be used. Examples of the triisocyanate include a trimethylolpropane adduct, a burette, and a trimer of the diisocyanate (the trimer contains an isocyanurate ring).

  The polyisocyanate (b) is preferably 4,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate, 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (isophorone diisocyanate) or the like.

  The polyisocyanate (b) can be used alone or in combination of two or more.

<Catalyst>
As the catalyst, for example, a tertiary amine compound and an organometallic compound are preferable.

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

The organometallic compound is preferably a tin compound or a non-tin compound.
Tin compounds include, for example, dibutyltin dichloride, dibutyltin oxide, dibutyltin dibromide, dibutyltin dimaleate, dibutyltin dilaurate (DBTDL), dibutyltin diacetate, dibutyltin sulfide, tributyltin sulfide, tributyltin oxide, tributyltin oxide. Examples include acetate, triethyltin ethoxide, tributyltin ethoxide, dioctyltin oxide, tributyltin chloride, tributyltin trichloroacetate, and tin 2-ethylhexanoate.
Non-tin compounds include, for example, titanium compounds such as dibutyl titanium dichloride, tetrabutyl titanate, and butoxy titanium trichloride; lead compounds such as lead oleate, lead 2-ethylhexanoate, lead benzoate, and lead naphthenate. Compounds; iron compounds such as iron 2-ethylhexanoate and iron acetylacetonate; cobalt compounds such as cobalt benzoate and cobalt 2-ethylhexanoate; zinc compounds such as zinc naphthenate and zinc 2-ethylhexanoate. A zirconium-based compound such as zirconium naphthenate; Among these, tin-based compounds are more preferable because they improve the reaction rate and cause less coloring.

  A single catalyst or two or more catalysts can be used.

  The catalyst is preferably used in an amount of 0.01 to 1.0 part by mass based on 100 parts by mass of the total of the polyisocyanate (b) and the polyol (a).

<Solvent>
For the production of the urethane polyol (A), one or more solvents can be used as necessary. Examples of the solvent include ketone solvents such as acetone and methyl ethyl ketone, ester solvents such as ethyl acetate, and hydrocarbon solvents such as toluene and xylene. Among them, ester solvents, hydrocarbon solvents, and the like are preferable from the viewpoint of the solubility of the urethane polyol (A) and the boiling point of the solvent.

<Method for producing urethane polyol (A)>
The method for producing the urethane polyol (A) is not particularly limited, and it can be produced by a known polymerization method such as a bulk polymerization method or a solution polymerization method.
The procedure of the manufacturing method is, for example,
(Procedure 1) One or more polyols (a), one or more polyisocyanates (b), if necessary, one or more catalysts, and if necessary, one or more solvents are charged into a flask all at once. procedure;
(Procedure 2) One or more polyols (a), one or more catalysts as needed, and one or more solvents as needed are charged into a flask, and one or more polyisocyanates (b) are added thereto. A procedure of dropwise addition.
(Procedure 3) One or more polyols (a) are charged with a final dropping amount, one or more catalysts as needed, and one or more solvents as needed. A procedure in which one or more polyisocyanates (b) are added dropwise, and then the remaining one or more polyols (a) are added dropwise.
Among these, (Procedure 2) and (Procedure 3) in which the reaction heat can be easily controlled are preferable.

  When a catalyst is used, the reaction temperature is preferably lower than 100 ° C, more preferably 70 to 95 ° C. When the reaction temperature is lower than 100 ° C., side reactions other than the urethane reaction can be suppressed, so that a desired urethane polyol (A) is easily obtained. When no catalyst is used, the reaction temperature is preferably 100 ° C. or higher, more preferably 110 ° C. or higher.

  The isocyanate group (NCO) of the polyisocyanate (b) and the hydroxyl group (OH) of the polyol (a) at the time of producing the urethane polyol (A) are 0.3 to 0.95 in terms of a molar ratio of NCO / OH. Preferably, it is 0.4 to 0.90, more preferably, 0.5 to 0.80. When the NCO / OH ratio is within the above range, a urethane polyol having an appropriate molecular chain can be formed, so that wettability and productivity are further improved.

  When a catalyst is used in the synthesis, it is preferable to deactivate the catalyst. The reaction terminator may be, for example, acetylacetone or the like.

  The reaction terminator may be used alone or in combination of two or more.

  The weight average molecular weight (Mw) of the urethane polyol (A) is preferably from 100,000 to 500,000, more preferably from 100,000 to 400,000, and still more preferably from 150,000 to 400,000. By adjusting the weight average molecular weight (Mw) to the above range, the pressure-sensitive adhesive layer has a constant cohesive force immediately after winding, so that indentation can be suppressed and the yield can be improved.

<Isocyanate curing agent (B)>
The isocyanate curing agent (B) is a known compound having a plurality of isocyanate groups. The isocyanate curing agent (B) is preferably the above polyisocyanate (b), and among them, aromatic polyisocyanate, aliphatic polyisocyanate, araliphatic polyisocyanate, and alicyclic polyisocyanate, and trimethylolpropane adduct thereof And burettes thereof, and trimers of these trifunctional isocyanates are more preferred.

  The isocyanate curing agent (B) can be used alone or in combination of two or more.

  The compounding amount of the isocyanate curing agent (B) is preferably 0.1 part by mass or more and 30 parts by mass or less, more preferably 1 to 25 parts by mass, and more preferably 3 to 20 parts by mass based on 100 parts by mass of the urethane polyol (A). Further preferred is 5 to 15 parts by mass. When the isocyanate curing agent (B) is blended in an appropriate amount, it is easy to obtain an appropriate adhesive strength and cohesive strength.

<Plasticizer (C)>
The pressure-sensitive adhesive of the present specification can further contain a plasticizer (C). Contains a plasticizer (C). Here, the wettability of the adhesive layer to the adherend is further improved. The plasticizer (C) is preferably a fatty acid ester having 8 to 30 carbon atoms or a phosphoric acid ester from the viewpoint of compatibility with other components.

  The fatty acid ester having 8 to 30 carbon atoms has 8 to 30 carbon atoms in the whole compound. For example, an ester of a monobasic acid or polybasic acid having 6 to 18 carbon atoms with a branched alcohol having 18 or less carbon atoms, Esters of unsaturated fatty acids or branched acids having the number of 14 to 18 and alcohols having 4 or less valency, esters of monobasic acids or polybasic acids having 6 to 18 carbon atoms and polyalkylene glycol, peroxides having unsaturated sites, etc. And the like.

  Examples of the ester of a monobasic acid or polybasic acid having 6 to 18 carbon atoms and a branched alcohol having 18 or less carbon atoms include, for example, isostearyl laurate, isopropyl myristate, isocetyl myristate, octyl dodecyl myristate, isopalmitate. Examples include stearyl, isocetyl stearate, octyldodecyl oleate, diisostearyl adipate, diisocetyl sebacate, trioleyl trimellitate, and triisocetyl trimellitate.

  The unsaturated fatty acids having 14 to 18 carbon atoms and the branched acids and the branched acids and the alcohols having 4 or less carbon atoms, which constitute the esters of the unsaturated fatty acids having 14 to 18 carbon atoms or the branched acids with the alcohols having 4 or less valences, are as follows. Examples of the unsaturated fatty acid or branched acid having 14 to 18 carbon atoms include myristoleic acid, oleic acid, linoleic acid, linolenic acid, isopalmitic acid, isostearic acid, and the like. Examples of the tetravalent or lower alcohol include ethylene glycol, propylene glycol, glycerin, trimethylolpropane, pentaerythritol, and sorbitan.

  Examples of the ester of a monobasic acid or polybasic acid having 6 to 18 carbon atoms with a polyalkylene glycol include, for example, polyethylene glycol dihexylate, polyethylene glycol di-2-ethylhexylate, polyethylene glycol dilaurate, polyethylene glycol dioleate, adipine Acid dipolyethylene glycol methyl ether;

  Fatty acid esters in which unsaturated sites are epoxidized with peroxide or the like, for example, epoxidized unsaturated fatty acids having 8 to 18 carbon atoms or epoxidized oils and fats such as epoxidized soybean oil, epoxidized linseed oil, and epoxidized cottonseed oil. An ester compound of a compound and a linear or branched alcohol having 1 to 6 carbon atoms is exemplified.

  Examples of the phosphate ester include an ester compound of phosphorous acid or phosphoric acid and a linear or branched alcohol having 2 to 18 carbon atoms.

  The plasticizer (C) can be used alone or in combination of two or more.

  The formula weight or the number average molecular weight (Mn) of the plasticizer (C) is preferably from 300 to 1,000, more preferably from 300 to 900, and still more preferably from 350 to 850, from the viewpoint of improving the wetting rate.

  The compounding amount of the plasticizer (C) is preferably from 0.1 to 100 parts by mass, more preferably from 1 to 80 parts by mass, even more preferably from 5 to 60 parts by mass based on 100 parts by mass of the urethane polyol (A). When an appropriate amount of the plasticizer (C) is blended, the wettability is further improved.

<Antioxidant (D)>
The pressure-sensitive adhesive of the present specification contains an antioxidant (D). When the antioxidant (D) is contained, the thermal decomposition of the crosslinked network between the urethane polyol (A) and the isocyanate curing agent (B) can be suppressed, so that a pressure-sensitive adhesive layer whose removability is hardly reduced after aging at high temperature can be obtained.
Examples of the antioxidant (D) include radical chain inhibitors such as phenolic antioxidants and amine antioxidants, sulfur antioxidants, and phosphorus antioxidants. Of these, phenolic antioxidants are preferred.

Phenolic antioxidants include, for example, 2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-4-ethylphenol, and stearin-β- (3 Monophenolic antioxidants such as 2,5-di-t-butyl-4-hydroxyphenyl) propionate;
2,2′-methylenebis (4-methyl-6-t-butylphenol), 2,2′-methylenebis (4-ethyl-6-t-butylphenol), 4,4′-thiobis (3-methyl-6-t -Butylphenol), 4,4′-butylidenebis (3-methyl-6-tert-butylphenol), and 3,9-bis [1,1-dimethyl-2- [β- (3-tert-butyl-4-hydroxy) Bisphenol antioxidants such as -5-methylphenyl) propionyloxy] ethyl] 2,4,8,10-tetraoxaspiro [5,5] undecane;
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-tert-butyl-4'-hydroxyphenyl) propionate] methane, bis [3,3'-bis- (4'-Hydroxy-3'-t-butylphenyl) butyric acid] glycol ester, and 1,3,5-tris (3 ', 5'-di-t-butyl-4'-hydroxybenzyl) -S-triazine- Polymer-type phenolic antioxidants such as 2,4,6- (1H, 3H, 5H) trione and tocophenol are exemplified.

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

  Examples of the phosphorus antioxidant include triphenyl phosphite, diphenyl isodecyl phosphite, and phenyl diisodecyl phosphite.

  The antioxidant (D) can be used alone or in combination of two or more.

  The compounding amount of the antioxidant (D) is preferably 0.1 to 10 parts by mass, more preferably 0.3 to 5 parts by mass, and preferably 0.5 to 3 parts by mass with respect to 100 parts by mass of the urethane polyol (A). Parts are more preferred.

<Antistatic agent (E)>
The pressure-sensitive adhesive of the present specification contains an antistatic agent (E). When the antistatic agent (E) is contained, electrostatic discharge at the time of peeling the pressure-sensitive adhesive sheet is suppressed, and for example, damage to electronic components incorporated in a display or the like is easily prevented.
Examples of the antistatic agent include an inorganic salt, an ionic liquid, an ionic solid, and a surfactant. Of these, ionic liquids are preferred. In addition, "ionic liquid" is also called room temperature molten salt, and shows the property of a liquid at 25 ° C.

  Inorganic salts include, for example, sodium chloride, potassium chloride, lithium chloride, lithium perchlorate, ammonium chloride, potassium chlorate, aluminum chloride, copper chloride, ferrous chloride, ferric chloride, ammonium sulfate, potassium nitrate, sodium nitrate, Sodium carbonate and sodium thiocyanate.

  The ionic liquid is a salt of a cation and an anion, and the cation is preferably, for example, an imidazolium ion, a pyridinium ion, an ammonium ion, or the like.

  Ionic liquids containing imidazolium ions include, for example, 1-ethyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide, 1,3-dimethylimidazolium bis (trifluoromethylsulfonyl) imide, and 1-butyl- 3-methylimidazolium bis (trifluoromethylsulfonyl) imide and the like.

  Ionic liquids containing pyridinium ions include, for example, 1-methylpyridinium bis (trifluoromethylsulfonyl) imide, 1-butylpyridinium bis (trifluoromethylsulfonyl) imide, 1-hexylpyridinium bis (trifluoromethylsulfonyl) imide, 1 -Octylpyridinium bis (trifluoromethylsulfonyl) imide, 1-hexyl-4-methylpyridiniumbis (trifluoromethylsulfonyl) imide, 1-hexyl-4-methylpyridinium hexafluorophosphate, 1-octyl-4-methyl Pyridinium bis (trifluoromethylsulfonyl) imide, 1-octyl-4-methylpyridinium bis (fluorosulfonyl) imide, 1-methylpyridinium bis (perfluoroethylsulfonyl) imid , And 1-methyl-pyridinium bis (perfluorobutylsulfonyl) imide, and the like.

  Ionic liquids containing ammonium ions include, for example, trimethylheptyl ammonium bis (trifluoromethanesulfonyl) imide, N, N-diethyl-N-methyl-N-propylammoniumbis (trifluoromethanesulfonyl) imide, N, N-diethyl-N -Methyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide, N, N-diethyl-N-methyl-N-heptylammonium bis (trifluoromethanesulfonyl) imide, and tri-n-butylmethylammonium bistrifluoromethanesulfonimide And the like.

  In addition, a known ionic liquid having a cation such as a pyrrolidinium ion, a phosphonium ion, or a sulfonium ion can be appropriately used.

  The ionic solid is a salt of a cation and an anion similarly to the ionic liquid, but shows a solid property at 25 ° C. under normal pressure. The cation is preferably, for example, an alkali metal ion, a phosphonium ion, a pyridinium ion, an ammonium ion, or the like.

  Ionic solids containing alkali metal ions include, for example, lithium bisfluorosulfonylimide, lithium bistrifluoromethylsulfonylimide, lithium bispentafluoroethylsulfonylimide, lithium bisheptafluoropropylsulfonylimide, lithium bisnonanefluorobutylsulfonylimide, sodium bis Fluorosulfonylimide, sodium bistrifluoromethylsulfonylimide, sodium bispentafluoroethylsulfonylimide, sodium bisheptafluoropropylsulfonylimide, sodium bisnonanefluorobutylsulfonylimide, potassium bisfluorosulfonylimide, potassium bistrifluoromethylsulfonylimide, potassium bis Pentafluoroethylsulfonylimide Potassium bis heptafluoropropyl imide, potassium bis nonane-fluoro-butyl imide and the like.

  Ionic solids containing phosphonium ions include, for example, tetrabutylphosphonium bisfluorosulfonylimide, tetrabutylphosphonium bistrifluoromethylsulfonylimide, tetrabutylphosphonium bispentafluoroethylsulfonylimide, tetrabutylphosphonium bisheptafluoropropylsulfonylimide, tetrabutylphosphonium Bisnonanefluorobutylsulfonylimide, tributylhexadecylphosphonium bisfluorosulfonylimide, tributylhexadecylphosphonium bistrifluoromethylsulfonylimide, tributylhexadecylphosphonium bispentafluoroethylsulfonylimide, tributylhexadecylphosphonium bisheptafluoropropylsulfonylimide, tributyl Xadecylphosphonium bisnonanefluorobutylsulfonylimide, tetraoctylphosphonium bisfluorosulfonylimide, tetraoctylphosphonium bistrifluoromethylsulfonylimide, tetraoctylphosphonium bispentafluoroethylsulfonylimide, tetraoctylphosphonium bisheptafluoropropylsulfonylimide, tetraoctylphosphonium Bisnonanefluorobutylsulfonylimide; and the like.

  Ionic solids containing pyridinium ions include, for example, 1-hexadecyl-4-methylpyridinium bisfluorosulfonylimide, 1-hexadecyl-4-methylpyridinium bistrifluoromethylsulfonylimide, 1-hexadecyl-4-methylpyridinium bispentafluoroethylsulfonyl Examples include imide, 1-hexadecyl-4-methylpyridinium bisheptafluoropropylsulfonylimide, 1-hexadecyl-4-methylpyridiniumbisnonanefluorobutylsulfonylimide, and the like.

  Ionic solids containing ammonium ions include, for example, tributylmethylbistrifluoromethylsulfonylimide, tributylmethylbispentafluoroethylsulfonylimide, tributylmethylbisheptafluoropropylsulfonylimide, tributylmethylmubisnonanefluorobutylsulfonylimide, octyltributylbistrifluoromine Methylsulfonylimide, octyltributylbispentafluoroethylsulfonylimide, octyltributylbisheptafluoropropylsulfonylimide, octyltributylmubisnonanefluorobutylsulfonylimide, tetrabutylbisfluorosulfonylimide, tetrabutylbistrifluoromethylsulfonylimide, tetrabutylbis Pentafluoroethylsulfonylimy , Tetrabutyl bis heptafluoropropylsulfonyl imide, tetrabutyl arm bis nonane-fluoro-butyl imide and the like.

  In addition, a known ionic solid having a cation such as a pyrrolidinium ion, an imidazolium ion, or a sulfonium ion can be appropriately used.

  Surfactants can be divided into non-ionic, anionic, cationic, and amphoteric types.

Nonionic surfactants include, for example, glycerin fatty acid ester, polyoxyalkylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene alkylamine, polyoxyethylene alkylamine fatty acid ester, fatty acid diethanolamide, polyether ester amide Type, ethylene oxide-epichlorohydrin type, polyetherester type and the like.
Examples of the anionic surfactant (excluding the ionic liquid and the ionic solid) include, for example, an alkyl sulfonate, an alkylbenzene sulfonate, an alkyl phosphate, and a polystyrene sulfonic acid type.
Examples of the cationic surfactant include a tetraalkylammonium salt, a trialkylbenzylammonium salt, and a quaternary ammonium base-containing acrylate polymer type.
Amphoteric surfactants include, for example, alkyl betaines and alkyl imidazolium betaines, amino acid type amphoteric surfactants such as higher alkylaminopropionates, higher alkyl dimethyl betaines, and betaine type amphoteric surfactants such as higher alkyl dihydroxyethyl betaines. And the like.

The antistatic agent (E) distinguishes between liquid and solid at 25 ° C.
The antistatic agent (E) which is liquid at 25 ° C. easily migrates to the interface between the pressure-sensitive adhesive layer and the adherend as compared with a solid, so that better antistatic properties are easily obtained.

  Further, the antistatic agent (E) which is solid at 25 ° C. is more likely to partially exist as an island having a sea-island structure in the adhesive layer than the liquid. Thereby, the stress relaxation property of the adhesive layer is improved, so that good substrate adhesion is easily obtained.

  Among them, the antistatic agent (E) is preferably 1-octyl-4-methylpyridinium bis (fluorosulfonyl) imide or tetrabutylphosphonium bis (trifluoromethanesulfonylimide).

  The antistatic agent (E) can be used alone or in combination of two or more.

  The compounding amount of the antistatic agent (E) is preferably 0.01 to 3 parts by mass, more preferably 0.03 to 2 parts by mass, and 0.06 to 1 part by mass with respect to 100 parts by mass of the urethane polyol (A). Parts are more preferred. When an appropriate amount of the antistatic agent (E) is blended, the removability after high-temperature aging hardly decreases, and the yield during the production of the pressure-sensitive adhesive sheet is further improved.

<Polyfunctional polyol (F)>
In this specification, the polyfunctional polyol (F) reacts with the isocyanate curing agent (B) together with the urethane polyol (A) to form a segment having a high crosslink density in the crosslink structure of the adhesive layer. The segment having a high crosslink density has excellent surface orientation due to the low molecular weight immediately before the reaction, and has the effect of strengthening the coating film surface and reducing indentation. The polyfunctional polyol (F) can utilize the residual polyol (a) when synthesizing the urethane polyol (A), or can be newly blended. The residual polyol (a) may be used in combination with the novel compound.

  As the polyfunctional polyol (F), a polyol having three or more hydroxyl groups in one molecule can be used among the polyols (a) already described. By setting the number of hydroxyl groups in one molecule to 3 or more, a segment having a high crosslinking density can be appropriately adjusted on the surface of the adhesive layer, so that indentation is further reduced.

  When a polyol having a primary hydroxyl group at a terminal is used as the polyfunctional polyol (F), the curing speed with the isocyanate curing agent (B) is increased, indentations are suppressed, and the yield is more likely to be improved.

  When a polyol having a secondary hydroxyl group at the molecular terminal is used as the polyfunctional polyol (F), it takes a long time until the completion of crosslinking, so that an adhesive layer with less curing distortion can be formed. As a result, the pressure-sensitive adhesive layer may be able to sufficiently adhere to a substrate that has not been subjected to an easy adhesion treatment such as a corona treatment.

  The polyfunctional polyol (F) preferably contains 2 to 50 parts by mass, more preferably 2 to 30 parts by mass, and still more preferably 4 to 20 parts by mass, based on 100 parts by mass of the urethane polyol (A). By including 2 to 50 parts by mass of the polyfunctional polyol (F), the ratio of the segment having a high crosslinking density on the surface of the pressure-sensitive adhesive layer can be appropriately adjusted, so that the indentation is further reduced.

  As the polyfunctional polyol (F), those listed in the above-mentioned polyol (a), those having 3 or more hydroxyl groups in one molecule and having a primary or secondary hydroxyl group at a molecular terminal can be used. Particularly, polyester polyol or polyether polyol is preferable.

  The number average molecular weight (Mn) of the polyfunctional polyol (F) is preferably in the range of 500 to 6,000, more preferably 1,000 to 5,000, and still more preferably 1,000 to 4,000. If it is 500 or more, the formation of a microgel locally reacted with the isocyanate curing agent (B) can be suppressed, and if it is 6,000 or less, the molecular weight between crosslinks can be reduced. The performance is further improved.

<Solvent>
As the solvent, a solvent that can be used in producing the urethane polyol (A) can be used, but an ester solvent, a hydrocarbon solvent, and the like are preferable. The solvent can be used alone or in combination of two or more.

<Other additives>
The pressure-sensitive adhesive of the present specification may include other additives as needed as long as the problem can be solved. Other additives include, for example, resins, fillers, metal powders, pigments, foils, softeners, ultraviolet absorbers, light stabilizers, surface lubricants, leveling agents, corrosion inhibitors, heat stabilizers, and polymerization inhibitors. , An antifoaming agent, a lubricant and the like.

  Examples of the filler include talc, calcium carbonate, and titanium oxide.

  Examples of the ultraviolet absorber include a benzophenone ultraviolet absorber, a benzotriazole ultraviolet absorber, a salicylic acid ultraviolet absorber, an oxalic anilide ultraviolet absorber, a cyanoacrylate ultraviolet absorber, and a triazine ultraviolet absorber. Can be

  Benzophenone ultraviolet absorbers include, for example, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-dodecyloxybenzophenone, 2,2′- Dihydroxy-4-dimethoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone, and bis (2-methoxy-4-hydroxy-5-benzoylphenyl ) Methane and the like.

  Benzotriazole-based ultraviolet absorbers include, for example, 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2- (2′-hydroxy-5′-tert-butylphenyl) benzotriazole, 2- (2 '-Hydroxy-3', 5'-di-tert-butylphenyl) benzotriazole, 2- (2'-hydroxy-3'-tert-butyl-5'-methylphenyl) -5-chlorobenzotriazole, 2- (2′-hydroxy-3 ′, 5′-di-tert-butylphenyl) 5-chlorobenzotriazole, 2- (2′-hydroxy-3 ′, 5′-di-tert-amylphenyl) benzotriazole, -(2′-hydroxy-4′-octoxyphenyl) benzotriazole, 2- [2′-hydroxy-3 ′-(3 ″, '', 5 '', 6 '',-tetrahydrophthalimidomethyl) -5'-methylphenyl] benzotriazole, 2,2'methylenebis [4- (1,1,3,3-tetramethylbutyl) -6 (2H-benzotriazol-2-yl) phenol] and [2 (2′-hydroxy-5′-methacryloxyphenyl) -2H-benzotriazole.

  Examples of the salicylic acid-based ultraviolet absorber include phenyl salicylate, p-tert-butylphenyl salicylate, and p-octylphenyl salicylate.

  Examples of the cyanoacrylate-based ultraviolet absorber include 2-ethylhexyl-2-cyano-3,3'-diphenylacrylate and ethyl-2-cyano-3,3'-diphenylacrylate.

  Examples of the light stabilizer include a hindered amine light stabilizer and an ultraviolet light stabilizer.

  Hindered amine light stabilizers include, for example, [bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate], bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, And methyl 1,2,2,6,6-pentamethyl-4-piperidyl sebacate.

  Examples of the ultraviolet stabilizer include nickel bis (octylphenyl) sulfide, [2,2′-thiobis (4-tert-octylphenolate)]-n-butylamine nickel, nickel complex-3,5-di-tert-butyl. -4-hydroxybenzyl-phosphate monoethylate, nickel-dibutyldithiocarbamate, benzoate-type quencher, nickel-dibutyldithiocarbamate, and the like.

  Examples of the leveling agent include an acrylic leveling agent, a fluorine-based leveling agent, and a silicon-based leveling agent. Acrylic leveling agents include, for example, polyflow no. 36, polyflow no. 56, polyflow no. 85HF, Polyflow No. 99C (manufactured by Kyoeisha Chemical Co., Ltd.) and the like. Examples of the fluorine-based leveling agent include Megafac F470N and Megafac F556 (all manufactured by DIC). Examples of the silicon-based leveling agent include Grandic PC4100 (manufactured by DIC).

<Adhesive sheet>
The pressure-sensitive adhesive sheet of the present specification includes a substrate and a pressure-sensitive adhesive layer that is a cured product of a pressure-sensitive adhesive. The adhesive layer can be formed on one side or both sides of the substrate. The surface of the pressure-sensitive adhesive layer that is not in contact with the substrate is usually protected with a release sheet until immediately before use in order to prevent adhesion of foreign matter.

As the base material, a flexible sheet and a plate material can be used without limitation. Examples of the substrate include plastic, paper, and metal foil, and a laminate thereof.
In order to improve the adhesiveness of the surface of the base material in contact with the adhesive layer, an easy adhesion treatment such as a dry treatment such as corona discharge treatment or a wet treatment such as application of an anchor coating agent can be performed in advance.

  Examples of the base plastic include, for example, ester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN); olefin resins such as polyethylene (PE), polypropylene (PP) and cycloolefin polymer (COP); Vinyl resins such as vinyl; amide resins such as nylon 66; urethane resins (including foams);

  The thickness of the substrate is usually about 10 to 300 μm. When a polyurethane sheet (including a foam) is used as the base material, the thickness is usually about 20 to 50,000 μm. Examples of the paper include plain paper, coated paper, and art paper. Examples of the metal foil include an aluminum foil and a copper foil.

  As the release sheet, a known release sheet in which a known release treatment such as a silicone release agent is applied to the surface of plastic or paper or the like can be used.

  Examples of the method for producing the pressure-sensitive adhesive sheet include a method in which a pressure-sensitive adhesive is applied to the surface of a substrate to form a coating layer, and then the coating layer is dried and cured to form a pressure-sensitive adhesive layer. The heating and drying temperature is usually about 60 to 150 ° C. The thickness of the adhesive layer is usually about 0.1 to 200 μm.

  Examples of the coating method include a known method such as a roll coater method, a comma coater method, a die coater method, a reverse coater method, a silk screen method, and a gravure coater method.

  Also, contrary to the above method, an adhesive is applied to the surface of the release sheet to form a coating layer, and then the coating layer is dried and cured to form an adhesive comprising a cured product of the adhesive of the present specification. A method of forming a layer and finally bonding a substrate to the exposed surface of the adhesive layer can be mentioned. When a release sheet is bonded in place of the substrate by the above method, a cast adhesive sheet of a release sheet / adhesive layer / release sheet is obtained.

<Laminate>
The laminate of the present specification includes a member selected from the group consisting of a transparent conductive film, a glass, an acrylic plate, a polycarbonate plate, an olefin plate, and an inorganic barrier layer, and a pressure-sensitive adhesive sheet.
Since the laminate includes the pressure-sensitive adhesive sheet formed from the pressure-sensitive adhesive of the present specification, for example, when manufacturing a display, it protects a member of the display that is easily damaged and can be easily peeled off after manufacturing. The display is, for example, an LCD, an OLED, or the like, and often includes a touch panel as another member.

  The touch panel includes, for example, a transparent electrode film. The transparent electrode film is, for example, a film in which a conductive layer such as ITO (indium tin oxide) is formed on a transparent film such as polyethylene terephthalate (PET) to a thickness of about 0.1 to 0.3 μm by sputtering or vapor deposition. A conductive layer (electrode layer) formed of ITO or the like is easily damaged. Therefore, when the pressure-sensitive adhesive sheet is provided, the conductive layer is hardly damaged by handling such as conveyance and processing.

  OLEDs include an inorganic barrier layer to protect light-emitting elements that are easily degraded. The inorganic barrier layer is a layer having a thickness of about 15 to 100 nm formed by depositing or sputtering an inorganic compound such as silicon nitride. Therefore, when the pressure-sensitive adhesive sheet is provided, the inorganic barrier layer is not easily damaged by handling such as transportation and processing of the OLED.

  Glass, an acrylic plate, a polycarbonate plate, and an olefin plate are optical members that constitute a part of a laminated body that constitutes a display such as an LCD or an OLED. Used for etc. Since the touch panel is required to be thin, the optical member is also thin and easily broken. Therefore, when the pressure-sensitive adhesive sheet is provided, the optical member is not easily damaged by handling such as transporting and processing the touch panel. In addition, the optical member may have an optical function such as a hard coat, a retardation, and a polarizing plate. The thickness of the optical member is about 10 to 1000 μm.

Hereinafter, embodiments of the present invention will be described with reference to examples. It goes without saying that the embodiments of the present invention are not limited to the examples. Hereinafter, “parts” means “parts by mass”. “%” Means “% by mass”. In addition, the compounding quantity in a table | surface is a mass part.
In addition, Examples 1 to 27, 29, 31 to 33, 35, and 37 to 73, which will be described later, are to be read as reference examples in order to match the invention according to claim 1.

[Synthesis example of urethane polyol (A)]
(Synthesis example 1)
500 parts of Kuraray polyol P-1010 (bifunctional polyester polyol, manufactured by Kuraray Co., Ltd.) and Kuraray polyol F-1010 (trifunctional polyester) in a four-necked flask equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, a thermometer, and a dropping funnel. (Polyol, manufactured by Kuraray Co., Ltd.) 500 parts, hexamethylene diisocyanate 140 parts, toluene 760 parts, and dioctyltin dilaurate 0.05 part as a catalyst were charged, and the temperature was gradually raised to 75 ° C., and a reaction was carried out for 3 hours. After confirming that the NCO characteristic absorption (2,270 cm ^-1 ) in the IR chart had disappeared, the mixture was cooled to 30 ° C. to terminate the reaction. The urethane polyol (A1) had a weight average molecular weight (Mw) of 150,000 and a conversion of more than 99%.

(Synthesis examples 2-36, 38, 39)
The urethane polyols (A) of Synthesis Examples 2 to 36, 38, and 39 were obtained by performing the same procedure as in Synthesis Example 1 except that the materials and the compounding ratio of Example 1 were changed as shown in Tables 1 to 4. Was. Table 1 shows Mw and conversion of the obtained urethane polyol (A). In addition, the compounding amount of the raw material in a table | surface is a non volatile matter conversion, and the unit of the numerical value which does not have a notice is [part].

(Synthesis Example 37)
200 parts of Kuraray polyol P-1010 (bifunctional polyester polyol, manufactured by Kuraray Co., Ltd.) and exenol 240 (trifunctional polyether polyol, in a four-necked flask equipped with a stirrer, a reflux condenser, a nitrogen inlet, a thermometer, and a dropping funnel) 550 parts of Asahi Glass Co., Ltd., 70 parts of hexamethylene diisocyanate, 547 parts of toluene, and 0.05 part of dioctyltin dilaurate as a catalyst were charged, and the temperature was gradually raised to 90 ° C., and the reaction was carried out for 30 minutes. Thereafter, a mixed solution of 100 parts of Kuraray polyol P-1010, 150 parts of Exenol 240, and 167 parts of toluene was dropped from the dropping funnel over 30 minutes. After confirming that the NCO characteristic absorption (2,270 cm ^-1 ) in the IR chart had disappeared, the mixture was cooled to 30 ° C. to terminate the reaction. The Mw of this urethane polyol (A37) was 210,000, and the conversion was 90%.

[material]
The materials used in the table are as follows.
<Polyol (a)>
(A1): P1010 ("Kuraray polyol P-1010", polyester polyol, Mn1000, number of hydroxyl groups 2, primary hydroxyl group, manufactured by Kuraray)
(A2): P3199 (“Preplast 3199”, polyester polyol, Mn2000, number of hydroxyl groups 2, primary hydroxyl group, manufactured by CRODA)
(A3): PP1000 ("SUNIX PP-1000", polyoxypropylene glycol, Mn1000, number of hydroxyl groups 2, secondary hydroxyl group, manufactured by Sanyo Chemical Industries, Ltd.)
(A4): PP2000 (“SUNIX PP-2000”, polyoxypropylene glycol, Mn2000, number of hydroxyl groups 2, secondary hydroxyl group, manufactured by Sanyo Chemical Industries, Ltd.)
(A5): Exe 510 ("Exenol 510", polyether polyol, Mn 4000, number of hydroxyl groups 2, primary hydroxyl group, manufactured by Asahi Glass Co., Ltd.)
(A6): GI1000 (“NISSO-PB GI-1000”, hydroxyl-terminated polybutadiene at both ends, Mn 1500, number of hydroxyl groups, primary hydroxyl group, manufactured by Nippon Soda Co., Ltd.)
(A7): GI3000 (“NISSO-PB GI-3000”, hydrogenated hydroxyl groups at both ends polybutadiene, Mn3100, hydroxyl group number 2, primary hydroxyl group, manufactured by Nippon Soda Co., Ltd.)
(A8): HLBH P2000 (“Krasol (registered trademark) HLBH P2000
, Terminal hydroxyl group-modified liquid polybutadiene, Mn2000, hydroxyl group number 1.95, primary hydroxyl group, CRAY VALLEY)
(A9): F1010 ("Kuraray polyol F-1010", polyester polyol, Mn1000, number of hydroxyl groups 3, primary hydroxyl group, manufactured by Kuraray)
(A10): F3010 ("Kuraray polyol F-3010", polyester polyol, Mn3000, number of hydroxyl groups 3, primary hydroxyl group, manufactured by Kuraray Co., Ltd.)
(A11): Exe 1030 (“Exenol 1030”, polyether polyol,
Mn1000, number of hydroxyl groups 3, secondary hydroxyl group, manufactured by Asahi Glass Co., Ltd.)
(A12): EXE 240 (“Exenol 240”, polyether polyol, Mn)
3000, hydroxyl group number 3, primary hydroxyl group, manufactured by Asahi Glass Co., Ltd.)
(A13): Exe 4030 (“Exenol 4030”, polyether polyol,
Mn 4000, number of hydroxyl groups 3, secondary hydroxyl group, manufactured by Asahi Glass Co., Ltd.)
(A14): Exe 828 (“Exenol 828”, polyether polyol, Mn)
5000, number of hydroxyl groups, primary hydroxyl group, manufactured by Asahi Glass Co., Ltd.)
(A15): P3010 (“Kuraray polyol P-3010”, polyester polyol, Mn1000, number of hydroxyl groups 3, primary hydroxyl group, manufactured by Kuraray)
(A16): GP3000 ("Sunnics GP-3000", polyether polyol, Mn3000, number of hydroxyl groups 3, secondary hydroxyl group, manufactured by Sanyo Chemical Industries, Ltd.)
(A17): AM302 ("ADEKA polyether AM-302", polyether polyol, Mn3000, number of hydroxyl groups 3, primary hydroxyl group, manufactured by ADEKA)
(A18): PTMG1000 (“PTMG1000”, polytetramethylene ether glycol, Mn1000, hydroxyl group number 2, primary hydroxyl group, manufactured by Mitsubishi Chemical Corporation)
(A19): S3011 ("Preminol S-3011", polyether polyol, Mn10000, hydroxyl group number 3, secondary hydroxyl group, manufactured by Asahi Glass Co., Ltd.)
(A20): GP1000 ("Sunnics GP-1000", polyether polyol, Mn1000, number of hydroxyl groups 3, secondary hydroxyl group, manufactured by Sanyo Chemical Industries, Ltd.)

<Polyisocyanate (b)>
(B1): HDI (hexamethylene diisocyanate, “Desmodur H” manufactured by Sumika Covest Low Urethane Co.),
(B2): TDI (tolylene diisocyanate, “Desmodur T-80” manufactured by Sumika Covest Low Urethane Co.),

<Isocyanate curing agent (B)>
(B1): HDI adduct (“Sumidur HT”, trimethylolpropane adduct of hexamethylene diisocyanate, manufactured by Sumika Kovestoururethane Co., Ltd.)
(B2): HDI Nurate ("Sumidur N3300", a nurate of hexamethylene diisocyanate, manufactured by Sumika Covestrourethane Co., Ltd.)

<Plasticizer (C)>
(C1): M182A ("Unistar M182A", methyl oleate, manufactured by NOF CORPORATION)
(C2): W262 (“Monosizer W262”, ether ester plasticizer, manufactured by DIC)
(C3): D55 ("ADEKASIZER D-55", epoxidized fatty acid alkyl ester, manufactured by ADEKA)
(C4): TOP ("TOP", tris (2-ethylhexyl) phosphate, manufactured by Daihachi Chemical)
(C5): IPP (“Exepearl IPP”, isopropyl palmitate, manufactured by Kao Corporation)

<Antioxidant (D)>
(D1): Irg1010 (“Irganox 1010”, pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], a phenolic antioxidant, manufactured by BASF)
(D2): IrgL135 ("Irganox L135", 3,5-benzenepropanoic acid
Bis (1,1-dimethyl-ethyl) -4-hydroxy-, C7-C9 side chain alkyl ester, phenolic antioxidant, BASF

<Antistatic agent (E)>
(E1): TFSI ammonium salt (tri-n-butylmethylammonium bistrifluoromethanesulfonimide, ionic liquid)
(E2): TFSI lithium salt (lithium bistrifluoromethanesulfonylimide, ionic solid)
(E3): FSI / pyridinium salt (1-octyl-4-methylpyridinium / bisfluorosulfonylimide, ionic liquid)
(E4): FSI imidazolium salt (1-ethyl-3-methyl-imidazolium bisfluorosulfonylimide, ionic liquid)
(E5): TFSI / phosphonium salt (tetrabutylphosphonium / bistrifluoromethanesulfonylimide, ionic solid)

<Polyfunctional polyol (F)>
Each of the above (a9) to (a20) was also used as a polyfunctional polyol.

[Measurement of weight average molecular weight (Mw) and number average molecular weight (Mn)]
The weight average molecular weight (Mw) and the number average molecular weight (Mn) were measured by a gel permeation chromatography (GPC) method. The measurement conditions are as follows. Note that both Mw and Mn are values in terms of polystyrene.
<Measurement conditions>
Apparatus: SHIMADZU Prominence (manufactured by Shimadzu Corporation),
Column: three SHOdex LF-804 (manufactured by Showa Denko KK) connected in series,
Detector: Differential refractive index detector Solvent: Tetrahydrofuran (THF)
Flow rate: 0.5 mL / min Solvent temperature: 40 ° C
Sample concentration: 0.1%
Sample injection volume: 100 μL

(Example 1)
100 parts of urethane polyol (A1) obtained in Synthesis Example 1, 2 parts of isocyanate curing agent (B1), 30 parts of plasticizer (C1), 0.7 parts of antioxidant (D1), 0 parts of antistatic agent (E1) .1 part, 10 parts of a polyfunctional polyol (F4 = a12), and 100 parts of ethyl acetate as a solvent were mixed and stirred with a disper to obtain an adhesive. In addition, the usage amount of each material except the solvent shows a non-volatile content conversion value [part].

A 50 μm-thick polyethylene terephthalate (PET) (“Lumilar T-60”, manufactured by Toray Industries, Inc.) was prepared as a substrate. Using a comma coater (registered trademark), the obtained pressure-sensitive adhesive is applied on the above base material at a coating speed of 3 m / min, a width of 30 cm and a thickness of 12 μm after drying to form a coating layer. did.
Next, the formed coating layer was dried at 100 ° C. for 1 minute using a drying oven to form an adhesive layer. A commercially available release sheet having a thickness of 38 μm was stuck on this adhesive layer, and further cured for 1 week at 23 ° C. and 50% RH to obtain an adhesive sheet.

(Examples 2 to 73, Comparative Examples 1 to 6)
Except that the materials and the compounding ratio of Example 1 were changed as shown in Tables 5 to 13, the same procedures as in Example 1 were carried out to obtain the pressure-sensitive adhesives and pressure-sensitive adhesive sheets of Examples 2 to 73 and Comparative Examples 1 to 6, respectively. Obtained.

[Evaluation items and evaluation methods]
The evaluation items and evaluation methods for the obtained pressure-sensitive adhesive and pressure-sensitive adhesive sheet are as follows.

(Indentation)
A pressure-sensitive adhesive sheet was prepared in the same manner as in Example 1 except that the coating speed in Example 1 was changed to 30 m / min and the width was changed to 150 cm, and a trace of a tape connecting the take-up roll and the pressure-sensitive adhesive sheet at regular intervals was prepared. Impression) was visually evaluated. The evaluation criteria are as follows.
：: No tape mark was observed at 10 m point. Excellence.
：: No tape mark was observed at a point of 25 m. Good.
Δ: No tape mark was observed at a point of 50 m. Practical.
X: Tape marks are observed at a point of 50 m. Not practical.

(Removability after high temperature aging)
The removability after aging at high temperature was evaluated by the adhesive strength.
The obtained pressure-sensitive adhesive sheet was prepared in a size of 25 mm in width and 100 mm in length, and was used as a measurement sample. Next, under an atmosphere of 23 ° C. and 50% RH, the release sheet was peeled off from the measurement sample, the exposed adhesive layer was adhered to a caustic soda glass plate, and a 2 kg roll was reciprocated once and pressed. Then, it was left under the condition of 100 ° C. for 24 hours. 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 ° were measured using a tensile tester (Tensilon: manufactured by Orientec) according to JISZ0237. The adhesion was measured. The adhesion was measured in the same manner as above except that the adherend was changed to an ITO film ("Tetraite TCF", manufactured by Oike Kogyo) and PET ("Lumirror T-60", manufactured by Toray Industries, Inc.).
The evaluation criteria are as follows.
A: Less than 100 mN / 25 mm. Excellence.
：: 100 mN / 25 mm or more and less than 200 mN / 25 mm. Good.
Δ: 200 mN / 25 mm or more and 300 mN / 25 mm. Practical.
X: More than 300 mN / 25 mm. Not practical.

(Adherend contamination)
The contamination from the pressure-sensitive adhesive was evaluated on the ITO surface after the “removability after high-temperature aging”.
The evaluation was performed by visually illuminating the adherend with an LED light in a dark room. The evaluation criteria are as follows.
：: No contamination is observed at all. Good.
Δ: Slight fogging is observed. Practical.
×: Clear clouding is observed. Not practical.

(Substrate adhesion)
The obtained pressure-sensitive adhesive sheet was prepared in a size of 50 mm in width and 50 mm in length, and was used as a measurement sample. Next, the release sheet was peeled off from the measurement sample under an atmosphere of 23 ° C. and 50% RH, and 11 cuts were made in the adhesive layer at intervals of 2 mm to a depth that reached the base material with a knife but did not cut. Next, eleven cuts were made in the direction perpendicular to the cuts in the same manner as above to form 100 grids in a grid pattern. The number of squares in which the adhesive layer was not removed from the base material when the thumb was strongly rubbed 10 times from above was evaluated. The evaluation criteria are as follows.
◎: 100 cells remaining. Excellence.
：: 90 to less than 100 cells remain. Good.
Δ: 75 to less than 90 cells remained. Practical.
X: Less than 75 cells remained. Not practical.

(Antistatic)
The obtained pressure-sensitive adhesive sheet was prepared in a size of 50 mm in width and 50 mm in length, and was used as a measurement sample. Next, under an atmosphere of 23 ° C. and 50% RH, the release sheet was peeled off from the measurement sample, and a probe of a surface resistance value measuring device (Hiresta-UX MCP-HT800, manufactured by Mitsubishi Chemical Analytech) was applied to the adhesive layer. The surface resistance was evaluated. The evaluation criteria are as follows.
A: Surface resistance value is less than 1 × 10 8. Excellence.
：: The surface resistance value is not less than 1 × 10 8 and less than 1 × 10 9. Good.
Δ: Surface resistance value is 1 × 10 9 or more and less than 1 × 10 10. Practical.
×: The surface resistance value is 1 × 10 10 or more. Not practical.

<Appendix>
  The present specification also discloses the invention of the following technical idea grasped from the embodiment.
[Supplementary Note 1]: Urethane polyol (A) having a weight average molecular weight of 100,000 to 500,000, which is a reaction product of polyol (a) and polyisocyanate (b), isocyanate curing agent (B), and antioxidant (D) Containing an antistatic agent (E) and a polyfunctional polyol (F),
  For 100 parts by mass of the urethane polyol (A),
  5 to 30 parts by mass of isocyanate curing agent (B), 0.5 to 10 parts by mass of antioxidant (D), 0.01 to 2 parts by mass of antistatic agent (E), and polyfunctional polyol (F) 4 to 50 parts by mass,
  An adhesive wherein the polyfunctional polyol (F) has a primary hydroxyl group at a terminal.
[Supplementary Note 2]: The pressure-sensitive adhesive according to Supplementary Note 1, wherein the polyfunctional polyol (F) has 3 or more hydroxyl groups in one molecule.
[Supplementary Note 3]: The pressure-sensitive adhesive according to Supplementary Note 1 or 2, further comprising a plasticizer (C).
[Supplementary Note 4]: The pressure-sensitive adhesive according to Supplementary Note 3, including 0.1 to 100 parts by mass of the plasticizer (C) based on 100 parts by mass of the urethane polyol (A).
[Supplementary Note 5]: An adhesive sheet including a base material and an adhesive layer that is a cured product of the adhesive according to any one of Supplementary Notes 1 to 4.
[Supplementary Note 6]: A laminate including a member selected from the group consisting of a transparent conductive film, glass, an acrylic plate, a polycarbonate plate, an olefin plate, and an inorganic barrier layer, and a pressure-sensitive adhesive sheet according to Supplementary Note 5.

Claims (10)

Urethane polyol (A) having a weight average molecular weight of 100,000 to 500,000, which is a reaction product of polyol (a) and polyisocyanate (b), isocyanate curing agent (B), antioxidant (D), antistatic agent ( E) and a polyfunctional polyol (F),
The antioxidant (D) is contained in an amount of 0.5 to 10 parts by mass with respect to 100 parts by mass of the urethane polyol (A),
Multifunctional polyol (F) may have a secondary hydroxyl group at the terminal, a number average molecular weight of 500 to 6000, Der Ru adhesive hydroxyl number is 3 or more in one molecule. The pressure-sensitive adhesive according to claim 1, further comprising a plasticizer (C). The pressure-sensitive adhesive according to claim 2 , comprising 0.1 to 100 parts by mass of the plasticizer (C) based on 100 parts by mass of the urethane polyol (A). The pressure-sensitive adhesive according to any one of claims 1 to 3 , wherein the polyfunctional polyol (F) is contained in an amount of 2 to 50 parts by mass with respect to 100 parts by mass of the urethane polyol (A). The pressure-sensitive adhesive according to any one of claims 1 to 4 , wherein the isocyanate curing agent (B) is contained in an amount of 0.1 to 30 parts by mass with respect to 100 parts by mass of the urethane polyol (A). The pressure-sensitive adhesive according to any one of claims 1 to 5 , comprising 0.01 to 3 parts by mass of the antistatic agent (E) based on 100 parts by mass of the urethane polyol (A). The pressure-sensitive adhesive according to any one of claims 1 to 6 , wherein the antistatic agent (E) is a liquid or a solid at 25 ° C. The pressure-sensitive adhesive according to any one of claims 1 to 7 , wherein the polyfunctional polyol (F) contains the same compound as the polyol (a). An adhesive sheet comprising a substrate and an adhesive layer which is a cured product of the adhesive according to any one of claims 1 to 8 . A laminate comprising: a member selected from the group consisting of a transparent conductive film, glass, an acrylic plate, a polycarbonate plate, an olefin plate, and an inorganic barrier layer; and a pressure-sensitive adhesive sheet according to claim 9 .