JP6536664B2 - Pressure-sensitive adhesive, pressure-sensitive adhesive sheet, and laminate - Google Patents

Description

  The present invention relates to an adhesive having antistatic properties.

  Display devices such as liquid crystal displays (LCD), flat panel displays (FPD) such as organic electro luminescence (OLED), and touch panel displays (TSP) combining a flat panel display and a touch panel are television (TV), personal computer It is widely used in PCs, portable information terminals, etc.

  Conventionally, a surface protective sheet has been widely used to protect an optical member used in a display device from adhesion of a scratch or dust.

  A pressure-sensitive adhesive containing a urethane resin (hereinafter referred to as a urethane pressure-sensitive adhesive) in the pressure-sensitive adhesive layer of the surface protective sheet has excellent adhesion and removability to various adherends represented by glass. It has been used since. In addition, the static electricity generated when peeling the surface protection sheet from the adherend may destroy the electronic device inside the FPD or TSP, which may require antistatic performance.

  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 and an ionic compound (D) not containing a hydroxyl group and an isocyanate group, There is disclosed a urethane-based pressure-sensitive adhesive composition comprising 0.05 to 5 parts by weight of the component (D) with respect to a total of 100 parts by weight of the components (A) to (C).

  Patent Document 2 discloses a urethane-based pressure-sensitive adhesive containing a polyurethane-based resin, wherein the polyurethane-based resin is obtained by curing a composition containing a polyol (A) and a polyfunctional isocyanate compound (B). And the 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. Disclosed is a urethane-based pressure-sensitive adhesive, wherein the urethane-based pressure-sensitive adhesive comprises an ionic liquid containing a fluoroorganic anion.

JP, 2017-105866, A JP, 2015-098503, A

  However, although the conventional pressure sensitive adhesive obtained the desired antistatic property by containing the antistatic agent, the metal catalyst in the pressure sensitive adhesive coordinates with the antistatic agent to reduce the reaction rate of the isocyanate curing agent. The curing speed was reduced because In addition, when the surface protection sheet is manufactured not by sheet but by roll-to-roll, a level difference that occurs when sticking the top of the surface protection sheet to the winding roll of the coating apparatus is added to the adhesive layer by the winding pressure, Since the influence of the step remains in the adhesive layer as an indentation because the surface protection sheet disappears, it has been necessary to discard the surface protective sheet until the indentation disappears. Furthermore, since the reduction of the curing speed due to the compounding of the antistatic agent reduces the cohesion of the adhesive layer immediately after coating, 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 speed causes a decrease in the crosslink density of the pressure-sensitive adhesive layer, and there is a problem that the adhesive strength after high temperature aging increases and the removability decreases. Furthermore, since the pressure-sensitive adhesive of Patent Document 2 is produced by a so-called one-shot method which does not use a 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 high yield and is less likely to be reduced in removability after high temperature aging, and a pressure-sensitive adhesive sheet.

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

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

Terms are defined prior to the description of the invention. In the present specification, an adherend refers to a partner to which an adhesive tape is attached.
In the present specification, the pressure-sensitive adhesive sheet includes a substrate and a pressure-sensitive adhesive layer made of a cured product of the pressure-sensitive adhesive of the present specification.
As used herein, "tape", "film" and "sheet" have the same meaning.
In the present specification, the main component refers to the component with the largest blending amount among the plurality of components to be blended.

  In the present specification, unless otherwise specified, "molecular weight" shall mean number average molecular weight (Mn). In addition, "Mn" is the number average molecular weight of polystyrene conversion calculated | required by gel permeation chromatography (GPC) measurement.

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

  In the pressure-sensitive adhesive of the present specification, the weight average molecular weight of the urethane polyol (A) is set high, and by combining the polyfunctional polyol (F), a disadvantage due to a decrease in curing speed occurring in the compounding of the antistatic agent (E) Can be eliminated to improve the reduction in yield. Furthermore, the pressure-sensitive adhesive of the present specification contains an antioxidant (D) to obtain a pressure-sensitive adhesive layer in which the removability is unlikely to decrease after high temperature aging.

The pressure-sensitive adhesive of the present specification can be used, for example, in a display such as a liquid crystal display (LCD) having a flat portion or a curved portion, an organic electroluminescence (OLED), or a touch panel using such a display. Moreover, it can be widely used for surface protection applications of electronic devices such as mobile phones, smart phones, portable terminals of 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 scratchable materials such as polyolefin, gold, silver, copper, ITO and the like.

Moreover, the use of an adhesive can be used for members, such as window glass, LED, a vehicle, wiring, etc., and these laminated bodies other than a display, for example.
Moreover, the adhesive sheet of this specification can be used also for the protection in the manufacturing process of various members, and the product after manufacture. 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 urethanization reaction. The polyisocyanate (b) is preferably a bifunctional isocyanate (b1) (also referred to as a diisocyanate) having two isocyanate groups in one molecule. 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 at a molar ratio (NCO / OH ratio) which is smaller than the hydroxyl group of the polyol (a). Thereby, the urethane polyol which has a hydroxyl group is obtained. In the urethane reaction, it is preferable to use a catalyst to accelerate the reaction. A solvent can be used for the urethanization reaction as needed.
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, a castor oil polyol and the like, and more preferably a polyether polyol, a polyester polyol and a polybutadiene modified polyol.
Although one type of polyol (a) may be used in the present specification, it is easy to adjust the cohesion and adhesion of the adhesive layer if two or more types are used in combination. When one type of polyol (a) is used, it is preferable to use a polyol having three or more hydroxyl groups. Moreover, when using two or more types of polyols (a), it is preferable to use together the polyol which has two hydroxyl groups, and the polyol which has three or more hydroxyl groups. When a polyol having three or more hydroxyl groups is used in combination, it is preferable to set the NCO / OH ratio (molar ratio) of the polyisocyanate (b) and the polyol (a) 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).

  The polyether polyol includes, for example, a reaction product obtained by addition polymerization of 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 and an amine.
Examples of hydroxyl group-containing compounds include bifunctional active hydrogen-containing compounds such as ethylene glycol (EG), propylene glycol (PG), 1,4-butanediol, neopentyl glycol, butylethyl pentanediol, etc .; glycerin, trimethylolpropane, etc. And trifunctional active hydrogen-containing compounds such as pentaerythritol and the like.
Examples of the amine include bifunctional active hydrogen-containing compounds such as N-aminoethyl ethanolamine, isophorone diamine and xylylene diamine; trifunctional active hydrogen-containing compounds such as triethanolamine; and tetrafunctional active hydrogen such as ethylene diamine and aromatic diamine Containing compounds; 5-functional active hydrogen-containing compounds such as diethylenetriamine etc. may be mentioned.

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

  The polyether polyol preferably has in the molecule an alkyleneoxy group derived from an active hydrogen-containing compound (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 polypropylene glycol having low crystallinity and easy expression of flexibility is particularly 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 600 to 4, since transparency and flexibility are easily developed. 000 is more preferred. By setting the Mn to 200 or more, reaction control at the time of synthesizing the urethane polyol (A) can be easily performed. Moreover, it is easy to adjust the cohesive force of a urethane polyol (A) in a suitable range by making Mn or less into 6,000.

  Examples of polyester polyols include compounds (esterified compounds) obtained by subjecting one or more types of polyol components and one or more types of acid components to an esterification reaction, or compounds (ring-opening polymers) synthesized by ring-opening polymerization of lactones. preferable.

  Examples of lactones 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-mentioned active hydrogen-containing compounds. 2,4-diethyl-1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 2-ethyl-1,3-hexanediol, 1,8-octanediol, 1,9- Nonane diol, 2-methyl-1, 8-octanediol, 1, 8-decanediol, octadecanediol, hexanetriol and the like.

  Examples of the acid component include 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, terephthalic acid, isophthalic acid, phthalic acid, isophthalic acid, terephthalic acid, 1,4-naphthalenedicarboxylic acid, and 4,4'-biphenyldicarboxylic acid And dimer acids, trimer acids, acid anhydrides thereof and the like.

  The number average molecular weight (Mn) of the polyester polyol is preferably 200 to 6,000, more preferably 500 to 6,000, still more preferably 500 to 4,000, and particularly preferably 500 to 3,000. By setting the Mn to 200 or more, reaction control at the time of synthesizing the urethane polyol (A) can be easily performed. Moreover, it is easy to adjust the cohesive force of a urethane polyol (A) in a suitable range by making Mn or less into 6,000.

  Polybutadiene-modified polyols, for example, have two or more hydroxyl group ends, and have a 1,2-vinyl site, a 1,4-cis site, a 1,4-trans site or a structure in which they are hydrogenated, It is a linear or branched polybutadiene.

  The number average molecular weight (Mn) of the polybutadiene modified polyol is preferably 200 to 6,000, more preferably 500 to 6,000, still more preferably 500 to 4,000, and particularly preferably 500 to 3,000. By setting the Mn to 200 or more, reaction control at the time of synthesizing the urethane polyol (A) can be easily performed. Moreover, it is easy to adjust the cohesive force of a urethane polyol (A) in a suitable range by making Mn or less into 6,000.

  The degree to which the polybutadiene modified polyol is hydrogenated is preferably that all of the double bond sites present prior to hydrogenation are hydrogenated, but in the present invention, some double bond sites remain. Also good.

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

  The polyol (a) may corrode the adherend if it contains an acidic functional group such as a carboxyl group or a sulfo group, so it is preferable to use a polyol having no acidic functional group.

  Among these, 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 polyisocyanate (b), for example, known polyisocyanates such as aromatic polyisocyanates, aliphatic polyisocyanates, araliphatic polyisocyanates, and alicyclic polyisocyanates can be used.

  As aromatic polyisocyanate, for example, 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 and the like.

  As aliphatic polyisocyanate, for example, 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 and the like.

  As aromatic aliphatic polyisocyanate, for example, ω, ω′-diisocyanate-1,3-dimethylbenzene, ω, ω′-diisocyanate-1,4-dimethylbenzene, ω, ω′-diisocyanate-1,4-diethylbenzene And 1,4-tetramethyl xylylene diisocyanate and 1,3-tetramethyl xylylene diisocyanate.

  As the alicyclic polyisocyanate, for example, 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate, 1,3-cyclopentadiisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, methyl-2 2,4-cyclohexanediisocyanate, methyl-2,6-cyclohexanediisocyanate, 4,4'-methylenebis (cyclohexylisocyanate), 1,4-bis (isocyanatemethyl) cyclohexane, and 1,4-bis (isocyanatemethyl) cyclohexane It can be mentioned.

  The above polyisocyanate is diisocyanate, but triisocyanate modified with the above diisocyanate can also be used. Examples of the triisocyanate include trimethylolpropane adduct, biuret, and trimer of the above diisocyanate (the trimer includes 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>
The catalyst is preferably, for example, a tertiary amine compound and an organic metal compound.

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

The organic metal compound is preferably a tin compound or a non-tin compound.
Examples of tin-based compounds include dibutyltin dichloride, dibutyltin oxide, dibutyltin dibromide, dibutyltin dimaleate, dibutyltin dilaurate (DBTDL), dibutyltin diacetate, dibutyltin sulfide, tributyltin sulfide, tributyltin oxide, and tributyltin. Acetate, triethyltin ethoxide, tributyltin ethoxide, dioctyltin oxide, tributyltin chloride, tributyltin trichloroacetate, tin 2-ethylhexanoate and the like can be mentioned.
Non-tin-based compounds include, for example, titanium-based compounds such as dibutyl titanium dichloride, tetrabutyl titanate, and butoxy titanium trichloride; lead-based compounds such as lead oleate, lead 2-ethylhexanoate, lead benzoate, and lead naphthenate Compounds; Iron-based compounds such as iron 2-ethylhexanoate and iron acetylacetonate; cobalt-based compounds such as cobalt benzoate and cobalt 2-ethylhexanoate; zinc-based compounds such as zinc naphthenate and zinc 2-ethylhexanoate And zirconium compounds such as zirconium naphthenate. Among these, tin compounds are more preferable because they have little reaction rate improvement and little coloring.

  The catalyst can be used alone or in combination of two or more.

  The catalyst is preferably used in an amount of 0.01 to 1.0 parts by mass with respect to 100 parts by mass in 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 required. 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 these, ester solvents, hydrocarbon solvents and the like are preferable in view of the solubility of the urethane polyol (a) and the boiling point of the solvent.

<Method of producing urethane polyol (A)>
The method for producing the urethane polyol (A) is not particularly limited, and the urethane polyol (A) can be produced by a known polymerization method such as bulk polymerization or solution polymerization.
The procedure of the manufacturing method is, for example,
(Procedure 1) One or more polyols (a), one or more polyisocyanates (b), and if necessary, one or more catalysts, and, if necessary, one or more solvents are collectively charged into the flask. procedure;
(Procedure 2) A flask is charged with one or more polyols (a), optionally one or more catalysts, and optionally one or more solvents, and one or more polyisocyanates (b) are added to the flask. Drop-wise addition procedure;
(Procedure 3) The remainder from the final drop of one or more polyols (a), and if necessary, one or more catalysts, and, if necessary, one or more solvents are charged into a flask, A step of adding one or more polyisocyanates (b) dropwise, and then dropping one or more polyols (a) in an amount which is left behind;
Among these, (procedure 2) (procedure 3) which is easy to control the reaction heat is preferable.

  When the catalyst is used, the reaction temperature is preferably less than 100 ° C, and more preferably 70 to 95 ° C. When the reaction temperature is less than 100 ° C., side reactions other than the urethane reaction can be suppressed, and thus it is easy to obtain a desired urethane polyol (A). When the catalyst is not used, the reaction temperature is preferably 100 ° C. or more, and more preferably 110 ° C. or more.

  The isocyanate group (NCO) of the polyisocyanate (b) and the hydroxyl group (OH) of the polyol (y) at the time of producing the urethane polyol (a) are 0.3 to 0.95 in 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 in the above range, a urethane polyol having an appropriate molecular chain can be formed, and thus the wettability and the productivity are further improved.

  When using a catalyst at the time of synthesis, it is preferable to inactivate 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 100,000 to 500,000, more preferably 100,000 to 400,000, and still more preferably 150,000 to 400,000. By adjusting the weight average molecular weight (Mw) to the above range, the adhesive layer has a certain cohesion immediately after winding, and therefore, the 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 polyisocyanate curing agent (B) is preferably the above-mentioned polyisocyanate (b), among which aromatic polyisocyanates, aliphatic polyisocyanates, araliphatic polyisocyanates, and alicyclic polyisocyanates, and trimethylolpropane adducts thereof And biuret bodies thereof, and trifunctional isocyanates and the like which are trimers thereof are more preferable.

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

  0.1 mass part or more and 30 mass parts or less are preferable with respect to 100 mass parts of urethane polyol (A), as for the compounding quantity of an isocyanate hardening | curing agent (B), 1-25 mass parts is more preferable, 3-20 mass parts 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 force and cohesive force.

<Plasticizer (C)>
The pressure-sensitive adhesive of the present specification can further contain a plasticizer (C). It 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, a phosphate ester, or the like 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 entire compound, for example, an ester of a monobasic acid or polybasic acid having 6 to 18 carbon atoms and a branched alcohol having 18 or less carbon atoms, carbon Esters of unsaturated fatty acids or branched acids with alcohols having a valence of 14 or less, alcohols with a valence of 6 to 18, esters of monobasic acids or polybasic acids having 6 to 18 carbon atoms with polyalkylene glycols, unsaturated sites such as peroxides, etc. And fatty acid esters epoxidized by

  Examples of esters of monobasic acids or polybasic acids having 6 to 18 carbon atoms and branched alcohols having 18 or less carbon atoms include, for example, isostearyl laurate, isopropyl myristate, isocetyl myristate, octyldodecyl myristate, iso palmitate Examples thereof include stearyl, isocetyl stearate, octyldodecyl oleate, diisostearyl adipate, diisocetyl sebacate, trioleyl trimellitate, triisocetyl trimellitate and the like.

  The unsaturated fatty acid having 14 to 18 carbon atoms, the unsaturated fatty acid having 14 to 18 carbon atoms, and the branched acid and an alcohol having 4 or fewer carbon atoms constituting the ester of the unsaturated fatty acid having 14 to 18 carbon atoms or the branched acid and the alcohol 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 alcohols having a valence of 4 or less include ethylene glycol, propylene glycol, glycerin, trimethylolpropane, pentaerythritol, sorbitan and the like.

  Examples of esters of monobasic acids or polybasic acids having 6 to 18 carbon atoms or polybasic acids with polyalkylene glycols include polyethylene glycol dihexylate, polyethylene glycol di-2-ethylhexylate, polyethylene glycol dilaurate, polyethylene glycol dioleate, and adipine. Acid dipolyethylene glycol methyl ether etc. may be mentioned.

  Fatty acid esters in which unsaturated sites are epoxidized with peroxides and the like are, for example, epoxidized fats and oils such as epoxidized soybean oil, epoxidized linseed oil, and epoxidized cottonseed oil, and epoxidized unsaturated fatty acids having 8 to 18 carbon atoms The ester compound of a compound, and a C1-C6 linear or branched alcohol etc. are mentioned.

  Examples of phosphoric esters include ester compounds 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.

  From a viewpoint of a wetting speed improvement etc., 300-1000 are preferable, as for the formula weight thru | or number average molecular weight (Mn) of a plasticizer (C), 300-900 are more preferable, and 350-850 are more preferable.

  The blending amount of the plasticizer (C) is preferably 0.1 to 100 parts by mass, more preferably 1 to 80 parts by mass, and still more preferably 5 to 60 parts by mass with respect to 100 parts by mass of the urethane polyol (A). When the plasticizer (C) is blended in an appropriate amount, the wettability is further improved.

<Antioxidant (D)>
The pressure-sensitive adhesive herein contains an antioxidant (D). When the antioxidant (D) is contained, the thermal decomposition of the crosslinked network of the urethane polyol (A) and the isocyanate curing agent (B) can be suppressed, whereby a pressure-sensitive adhesive layer in which the removability is unlikely to decrease after high temperature aging can be obtained.
Examples of the antioxidant (D) include radical chain inhibitors such as phenol-based antioxidants and amine-based antioxidants, sulfur-based antioxidants, phosphorus-based antioxidants, and the like. Among 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 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-t-butylphenol), and 3,9-bis [1,1-dimethyl-2- [β- (3-t-butyl-4-hydroxyl Bisphenol-based 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-t-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- Examples thereof include high molecular weight phenolic antioxidants such as 2,4,6- (1H, 3H, 5H) trione and tocophenol.

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

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

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

  0.1-10 mass parts is preferable with respect to 100 mass parts of urethane polyols (A), as for the compounding quantity of antioxidant (D), 0.3-5 mass parts is more preferable, and 0.5-3 mass Parts are more preferred.

<Antistatic agent (E)>
The pressure-sensitive adhesive herein 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, breakage of an electronic component or the like incorporated in a display or the like can be easily prevented.
Examples of the antistatic agent include inorganic salts, ionic liquids, ionic solids, surfactants and the like. Among these, ionic liquids are preferred. The “ionic liquid” is also referred to as a normal temperature molten salt, and exhibits a liquid property 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, sodium thiocyanate and the like can be mentioned.

  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.

  An ionic liquid containing an imidazolium ion is, 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.

  Examples of the ionic liquid containing pyridinium ion include 1-methylpyridinium bis (trifluoromethylsulfonyl) imide, 1-butylpyridinium bis (trifluoromethylsulfonyl) imide, 1-hexylpyridinium bis (trifluoromethylsulfonyl) imide, -Octylpyridinium bis (trifluoromethylsulfonyl) imide, 1-hexyl-4-methylpyridinium bis (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) imime , And 1-methyl-pyridinium bis (perfluorobutylsulfonyl) imide, and the like.

  The ionic liquid containing ammonium ion is, for example, trimethylheptylammonium 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 (trifluoromethanesulfonyl) imide, and tri-n-butylmethylammonium bistrifluoromethanesulfonimide Etc.

  In addition, known ionic liquids in which the cation is pyrrolidinium ion, phosphonium ion, sulfonium ion or the like can be appropriately used.

  The ionic solid is, like the ionic liquid, a salt of a cation and an anion, but exhibits solid properties 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 and the like.

  The ionic solid containing an alkali metal ion is, 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 Pentafluoroethyl sulfonyl imide Potassium bis heptafluoropropyl imide, potassium bis nonane-fluoro-butyl imide and the like.

  The ionic solid containing phosphonium ion is, for example, 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 heptafluoropropyl sulfonyl imide, tributyl Xadecyl phosphonium bis nonane fluorobutyl sulfonyl imide, tetraoctyl phosphonium bis fluoro sulfonyl imide, tetra octyl phosphonium bis trifluoromethyl sulfonyl imide, tetra octyl phosphonium bis penta fluoro ethyl sulfonyl imide, tetra octyl phosphonium bis hepta fluoro propyl sulfonyl imide, tetra octyl phosphonium Bisnonane fluorobutyl sulfonyl imide etc. are mentioned.

  The ionic solid containing pyridinium ion is, 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.

  The ionic solid containing ammonium ion is, for example, tributyl methyl bis trifluoromethyl sulfonyl imide, tri butyl methyl bis penta fluoro ethyl sulfonyl imide, tri butyl methyl bis hepta fluoro propyl sulfonyl imide, tri butyl methyl bis nonane fluoro butyl sulfonyl imido, octyl tributyl bis trifluoro Methyl sulfonyl imide, octyl tributyl bis pentafluoro ethyl sulfonyl imide, octyl tri butyl bis hepta fluoro propyl sulfonyl imide, octyl tri butyl mb bis nonane fluoro butyl sulfonyl imide, tetra butyl bis fluoro sulfonyl imide, tetra butyl bis trifluoromethyl sulfonyl imide, tetra butyl bis Pentafluoroethyl sulfonylimi , Tetrabutyl bis heptafluoropropylsulfonyl imide, 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 can be classified into nonionic, anionic, cationic and amphoteric types.

Nonionic surfactants include, for example, glycerin fatty acid ester, polyoxyalkylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl amine, polyoxyethylene alkyl amine fatty acid ester, fatty acid diethanolamide, polyether ester amide Types, ethylene oxide-epichlorohydrin types, and polyether ester types.
Anionic surfactants (except for ionic liquids and ionic solids) include, for example, alkyl sulfonates, alkyl benzene sulfonates, alkyl phosphates, and polystyrene sulfonates.
Examples of cationic surfactants include tetraalkyl ammonium salts, trialkyl benzyl ammonium salts, and quaternary ammonium base-containing acrylate polymer types.
Amphoteric surfactants include, for example, amino acid type amphoteric surfactants such as alkyl betaines and alkyl imidazolium betaines, higher alkyl amino propionates, and betaine type amphoteric surfactants such as higher alkyl dimethyl betaines and higher alkyl dihydroxyethyl betaines. Etc.

Antistatic agents (E) are distinguished as liquids or solids 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 a better antistatic property is easily obtained.

  In addition, a part of the antistatic agent (E) which is solid at 25 ° C. is more likely to be present as an island having a sea-island structure in the adhesive layer, as compared with the liquid. Since the stress relaxation property of the adhesion layer improves by this, it is easy to acquire favorable base-material adhesiveness.

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

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

  0.01-3 mass parts is preferable with respect to 100 mass parts of urethane polyols (A), as for the compounding quantity of antistatic agent (E), 0.03-2 mass parts is more preferable, and 0.06-1 mass. Parts are more preferred. When an appropriate amount of the antistatic agent (E) is blended, the removability after aging at high temperatures hardly decreases, and the yield at the time of producing the pressure-sensitive adhesive sheet is further improved.

<Polyfunctional polyol (F)>
In the present specification, the polyfunctional polyol (F) reacts with the isocyanate curing agent (B) together with the urethane polyol (A) to form a segment with high crosslinking density in the crosslinked structure of the adhesive layer. The segment having a high crosslink density has excellent molecular surface orientation just before the reaction and is excellent in surface orientation, thereby strengthening the coating film surface and exhibiting an effect of reducing an indentation. The multifunctional polyol (F) can be used newly or by utilizing the residual polyol (a) in synthesizing the urethane polyol (A). The residual polyol (a) may be used in combination with the new compound.

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

  When a polyol having a primary hydroxyl group at the end is used as the polyfunctional polyol (F), the curing rate with the isocyanate curing agent (B) is increased, the indentation is suppressed, and the yield is more easily improved.

  When a polyol having a secondary hydroxyl group at the molecular terminal is used for the polyfunctional polyol (F), it takes a long time to complete the crosslinking, so that an adhesive layer with little curing strain can be formed. In this case, the pressure-sensitive adhesive layer may be sufficiently in close contact with the substrate on which the easy adhesion treatment such as corona treatment is not performed.

  The polyfunctional polyol (F) is preferably contained in an amount of 2 to 50 parts by mass, more preferably 2 to 30 parts by mass, and still more preferably 4 to 20 parts by mass with respect to 100 parts by mass of the urethane polyol (A). By including 2 to 50 parts by mass of the polyfunctional polyol (F), it is possible to appropriately adjust the proportion of the segment having a high crosslink density on the surface of the adhesive layer, and the indentation is further reduced.

  Among the polyfunctional polyols (F) listed above for the polyol (a), those having three or more hydroxyl groups in one molecule and having primary or secondary hydroxyl groups at the molecular terminal can be used. In particular, polyester polyols or polyether polyols are preferred.

  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. Sex improves more.

<Solvent>
Although a solvent which can be used in the production of the urethane polyol (A) can be used as the solvent, ester solvents, hydrocarbon solvents and the like are preferable. The solvents may be used alone or in combination of two or more.

<Other additives>
The pressure-sensitive adhesive of the present specification can contain other additives as needed as long as the problems can be solved. Other additives include, for example, resins, fillers, metal powders, pigments, foils, softeners, UV absorbers, light stabilizers, surface lubricants, leveling agents, corrosion inhibitors, heat stabilizers, polymerization inhibitors , Antifoam agents, lubricants and the like.

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

  Examples of UV absorbers include benzophenone UV absorbers, benzotriazole UV absorbers, salicylic acid UV absorbers, oxalic acid anilide UV absorbers, cyanoacrylate UV absorbers, and triazine UV absorbers. Be

  Benzophenone-based UV absorbers are, 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) And the like.

  Examples of the benzotriazole-based ultraviolet absorber include 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 -(2'-hydroxy-4'-octoxyphenyl) benzotriazole, 2- [2'-hydroxy-3 '-(3' ', '', 5 '', 6 ''-tetrahydrophthalimidomethyl) -5'-methylphenyl] benzotriazole, 2, 2 'methylene bis [4- (1, 1, 3, 3- tetramethyl butyl) -6- (2H-benzotriazol-2-yl) phenol], and [2 (2'-hydroxy-5'-methacryloxyphenyl) -2H-benzotriazole, etc. may be mentioned.

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

  Examples of cyanoacrylate UV absorbers include 2-ethylhexyl 2-cyano-3,3'-diphenyl acrylate and ethyl 2-cyano-3,3'-diphenyl acrylate.

  Examples of light stabilizers include hindered amine light stabilizers and ultraviolet light stabilizers.

  The hindered amine light stabilizers are, 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 and the like.

  UV stabilizers are, for example, 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.

  As a leveling agent, an acrylic type leveling agent, a fluorine type leveling agent, a silicon type leveling agent etc. are mentioned. As commercially available leveling agents, acrylic leveling agents are exemplified by, for example, polyflow no. 36, polyflow no. 56, Polyflow No. 85HF, polyflow no. Examples include 99C (made by Kyoeisha Chemical Co., Ltd.) and the like. Examples of fluorine-based leveling agents include Megafac F470N and Megafac F556 (all manufactured by DIC). Examples of the silicon-based leveling agent include Grandic PC 4100 (manufactured by DIC Corporation).

<Adhesive sheet>
The pressure-sensitive adhesive sheet herein comprises a substrate and a pressure-sensitive adhesive layer which is a cured product of a pressure-sensitive adhesive. The adhesive layer can be formed on one side or both sides of the substrate. In addition, in order to prevent adhesion of a foreign material, the surface which is not in contact with the base material of the adhesion layer is normally protected with a peeling sheet until just before using.

As the substrate, flexible sheets and plate materials can be used without limitation. Examples of the substrate include plastics, paper, and metal foils, laminates of these, and the like.
On the surface of the base material in contact with the adhesive layer, for the purpose of improving adhesion, for example, an easy adhesion process such as a dry process such as corona discharge treatment or a wet process such as anchor coating agent application can be performed.

  Examples of the base plastic include 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); and the like.

  The thickness of the substrate is usually about 10 to 300 μm. Moreover, the thickness in the case of using a polyurethane sheet (a foam is included) for a base material is about 20-50,000 micrometers normally. Examples of paper include plain paper, coated paper, and art paper. Examples of the metal foil include aluminum foil, copper foil and the like.

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

  Examples of the method for producing a pressure-sensitive adhesive sheet include a method of applying a pressure-sensitive adhesive on the surface of a substrate to form a coated layer, and then drying and curing the coated layer 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 known methods 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 coated layer, and then the coated layer is dried and cured to form an adhesive comprising the cured product of the adhesive of the present specification. There is a method of forming a layer and finally bonding a substrate to the exposed surface of the adhesive layer. When a release sheet is attached in place of the substrate by the above method, a cast pressure-sensitive adhesive sheet of release sheet / adhesive layer / release sheet is obtained.

<Laminate>
The laminate of the present specification comprises a member selected from the group consisting of a transparent conductive film, glass, an acrylic plate, a polycarbonate plate olefin plate, and an inorganic barrier layer, and an 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 the members of the display that is prone to breakage and can be easily peeled off after manufacture. 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 a film in which a conductive layer such as ITO (indium tin oxide) is formed to a thickness of about 0.1 to 0.3 μm by sputtering or vapor deposition on the surface of a transparent film such as polyethylene terephthalate (PET). The conductive layer (electrode layer) formed of ITO or the like is easily broken. Therefore, when the pressure-sensitive adhesive sheet is provided, the conductive layer is less likely to be damaged by handling such as conveyance and processing.

  OLEDs are provided with an inorganic barrier layer to protect light emitting elements that are prone to degradation. The inorganic barrier layer is, for example, a layer having a thickness of about 15 to 100 nm formed by vapor deposition or sputtering of an inorganic compound such as silicon nitride. Therefore, when the pressure-sensitive adhesive sheet is provided, the inorganic barrier layer is less likely to be damaged by handling such as transportation and processing of the OLED.

  Glass, acrylic plate, polycarbonate plate and olefin plate are optical members constituting a part of a laminate constituting a display, such as LCD and OLED. The optical members protect liquid crystal elements, for example, or the outermost surface of a touch panel 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 less likely to be damaged by handling such as conveyance, processing, etc. of the touch panel. Further, the optical member may have an optical function such as a hard coat, a retardation, or a polarizing plate. The thickness of the optical member is about 10 to 1000 μm.

Hereinafter, embodiments of the present invention will be described by way of examples. Needless to say, the embodiments of the present invention are not limited to the examples. Hereinafter, “parts” means “parts by mass”. Moreover, "%" means "mass%". In addition, the compounding quantity in a table | surface is a mass part.
In addition, in order to be consistent with the invention according to claim 1, embodiments 1, 6, 14, 15, 28, 30, 34, 36 described later shall be read as reference examples.

[Synthesis Example of Urethane Polyol (A)]
Synthesis Example 1
A 4-neck flask equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, a thermometer, and a dropping funnel, 500 parts of Kuraray polyol P-1010 (bifunctional polyester polyol, manufactured by Kuraray Co., Ltd.), Kuraray polyol F-1010 (trifunctional polyester) 500 parts of polyol, Kuraray Co., Ltd., 140 parts of hexamethylene diisocyanate, 760 parts of toluene, and 0.05 parts of dioctyltin dilaurate as a catalyst were charged, and the temperature was gradually raised to 75 ° C., and the reaction was carried out for 3 hours. After confirming that the NCO characteristic absorption (2,270 cm.sup.- ¹ ) in the IR chart disappeared, the reaction was cooled down to 30.degree. C. to complete the reaction. The weight average molecular weight (Mw) of this urethane polyol (A1) was 150,000, and the conversion was over 99%.

(Synthesis examples 2 to 36, 38, 39)
The urethane polyol (A) of Synthesis Examples 2 to 36, 38, and 39 is obtained by performing in the same manner as in Synthesis Example 1 except that the materials and the compounding ratio of Example 1 are changed as shown in Tables 1 to 4. The The Mw and conversion of the resulting urethane polyol (A) are shown in Table 1. In addition, the compounding quantity of the raw material in a table | surface is non-volatile-content conversion, and the unit of the numerical value which has no notice in particular is a [part].

(Composition Example 37)
A 4-neck flask equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, a thermometer, and a dropping funnel, 200 parts of Kuraray polyol P-1010 (bifunctional polyester polyol, manufactured by Kuraray), Exenol 240 (a trifunctional polyether polyol, 550 parts of Asahi Glass Co., Ltd., 70 parts of hexamethylene diisocyanate, 547 parts of toluene, and 0.05 parts of dioctyltin dilaurate as a catalyst were charged, and the temperature was gradually raised to 90 ° C. to carry out a reaction 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 added dropwise over 30 minutes from the dropping funnel. After confirming that the NCO characteristic absorption (2,270 cm.sup.- ¹ ) in the IR chart disappeared, the reaction was cooled down to 30.degree. C. to complete 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, Mn 1000, hydroxyl group number 2, primary hydroxyl group, manufactured by Kuraray Co., Ltd.)
(A2): P3199 ("Pliplast 3199", polyester polyol, Mn 2000, hydroxyl number 2, primary hydroxyl group, CRODA)
(A3): PP 1000 ("Sannicks PP-1000", polyoxypropylene glycol, Mn 1000, number of hydroxyl groups 2, secondary hydroxyl group, manufactured by Sanyo Chemical Industries, Ltd.)
(A4): PP 2000 ("Sannicks PP-2000", polyoxypropylene glycol, Mn 2000, number of hydroxyl groups 2, secondary hydroxyl group, manufactured by Sanyo Chemical Industries, Ltd.)
(A5): Exe 510 (“Exenol 510”, polyether polyol, Mn 4000, hydroxyl number 2, primary hydroxyl group, manufactured by Asahi Glass Co., Ltd.)
(A6): GI1000 (“NISSO-PB GI-1000”, both-end hydroxyl group hydrogenated polybutadiene, Mn1500, hydroxyl number 2, primary hydroxyl group, Nippon Soda Co., Ltd.)
(A7): GI 3000 (“NISSO-PB GI-3000”, both-end hydroxyl group hydrogenated polybutadiene, Mn 3100, 2 hydroxyl groups, primary hydroxyl group, manufactured by Nippon Soda Co., Ltd.)
(A8): HLBH P2000 ("Krasol (registered trademark) HLBH P2000", terminal hydroxyl group-modified liquid polybutadiene, Mn 2000, number of hydroxyl groups: 1.95, primary hydroxyl group, manufactured by CRAY VALLEY)
(A9): F1010 ("Kuraray polyol F-1010", polyester polyol, Mn 1000, number of hydroxyl groups: 3, primary hydroxyl group, manufactured by Kuraray Co., Ltd.)
(A10): F3010 ("Kuraray polyol F-3010", polyester polyol, Mn 3000, number of hydroxyl groups: 3, primary hydroxyl group, manufactured by Kuraray Co., Ltd.)
(A11): Exe 1030 ("Exenol 1030", polyether polyol, Mn 1000, number of hydroxyl groups 3, secondary hydroxyl group, manufactured by Asahi Glass Co., Ltd.)
(A12): Exe 240 ("Exenol 240", polyether polyol, Mn 3000, number of hydroxyl groups 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): Exce 828 ("Exenol 828", polyether polyol, Mn 5000, number of hydroxyl groups 3, primary hydroxyl group, manufactured by Asahi Glass Co., Ltd.)
(A15): P3010 ("Kuraray polyol P-3010", polyester polyol, Mn 1000, number of hydroxyl groups: 3, primary hydroxyl group, manufactured by Kuraray Co., Ltd.)
(A16): GP 3000 ("Sannix GP-3000", polyether polyol, Mn 3000, number of hydroxyl groups 3, secondary hydroxyl group, manufactured by Sanyo Chemical Industries, Ltd.)
(A17): AM 302 ("ADEKA POLYETHER AM-302", polyether polyol, Mn 3000, number of hydroxyl groups 3, primary hydroxyl group, manufactured by ADEKA)
(A18): PTMG 1000 ("PTMG 1000", polytetramethylene ether glycol, Mn 1000, hydroxyl number 2, primary hydroxyl group, manufactured by Mitsubishi Chemical Corporation)
(A19): S3011 ("Preminol S-3011", polyether polyol, Mn 10000, number of hydroxyl groups 3, secondary hydroxyl group, manufactured by Asahi Glass Co., Ltd.)
(A20): GP 1000 (“Sannix GP-1000”, polyether polyol, Mn 1000, 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 Kobethurourethane),
(B2): TDI (tolylene diisocyanate, "Desmodur T-80" manufactured by Sumika Kobethurourethane Co., Ltd.),

<Isocyanate curing agent (B)>
(B1): HDI adduct ("Sumidur HT", trimethylolpropane adduct of hexamethylene diisocyanate, manufactured by Sumika Kovestro Urethane Co., Ltd.)
(B2): HDI nurate ("Sumidur N3300", a nurate of hexamethylene diisocyanate, manufactured by Sumika Kobethurourethane Co., Ltd.)

<Plasticizer (C)>
(C1): M182A ("Unister 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 Kogyo Chemical Co., Ltd.)
(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], phenolic antioxidant, manufactured by BASF)
(D2): Irg L 135 (“Irganox L 135”, benzenepropanoic acid 3,5-bis (1,1-dimethyl-ethyl) -4-hydroxy-, C7-C9 side chain alkyl ester, phenolic antioxidant, BASF Company-made)

<Antistatic agent (E)>
(E1): TFSI ammonium salt (tri-n-butylmethyl ammonium bistrifluoromethane sulfone imide, ionic liquid)
(E2): TFSI lithium salt (lithium bis trifluoromethanesulfonyl imide, ionic solid)
(E3): FSI pyridinium salt (1-octyl-4-methylpyridinium bisfluorosulfonyl imide, ionic liquid)
(E4): FSI imidazolium salt (1-ethyl-3-methyl-imidazolium bisfluorosulfonyl imide, ionic liquid)
(E5): TFSI phosphonium salt (tetrabutylphosphonium bistrifluoromethanesulfonyl imide, ionic solid)

<Polyfunctional polyol (F)>
The above (a9) to (a20) were also used as polyfunctional polyols, respectively.

[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 gel permeation chromatography (GPC). The measurement conditions are as follows. In addition, both Mw and Mn are polystyrene conversion values.
<Measurement conditions>
Device: 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 the urethane polyol (A1) obtained in Synthesis Example 1, 2 parts of an isocyanate curing agent (B1), 30 parts of a plasticizer (C1), 0.7 parts of an antioxidant (D1), and an antistatic agent (E1) 0 One part, 10 parts of a multifunctional polyol (F4 = a12), and 100 parts of ethyl acetate as a solvent were blended, and the mixture was stirred with a disper to obtain a pressure sensitive adhesive. In addition, the usage-amount of each material except a solvent shows non-volatile-content conversion value [part].

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

(Examples 2 to 73, Comparative Examples 1 to 6)
The pressure-sensitive adhesive and pressure-sensitive adhesive sheet of Examples 2 to 73 and Comparative Examples 1 to 6 are carried out in the same manner as in Example 1 except that the material and the compounding ratio of Example 1 are changed as shown in Tables 5 to 13. Obtained.

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

(Indentation)
An 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 to 150 cm, and a mark of the tape connecting the winding roll and the adhesive sheet every fixed distance The indentation was evaluated visually. Evaluation criteria are as follows.
◎: No tape mark is observed at 10 m. Excellent.
○: No tape mark is observed at 25 m. Good.
Fair: No tape mark is observed at 50 m. Practical use possible.
×: A tape mark is observed at 50 m. Not practical.

(Removability after high temperature aging)
The removability after high temperature aging was evaluated by adhesion.
The obtained pressure-sensitive adhesive sheet was prepared to be 25 mm wide and 100 mm long and used as a measurement sample. Then, the release sheet was peeled off from the measurement sample 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 pressure bonded. Thereafter, it was left at 100 ° C. for 24 hours. Next, after air cooling in an atmosphere of 23 ° C. and 50% RH for 30 minutes, in accordance with JIS Z 0237, using a tensile tester (Tensilon: manufactured by ORIENTEC Co., Ltd.), under the conditions of peeling speed 300 mm / min and peeling angle 180 °. The adhesion was measured. Further, the adhesion was measured in the same manner as described above except that the adherend was changed to an ITO film ("Terate TCF", manufactured by Oike Kogyo Co., Ltd.) and PET ("Lumirror T-60" manufactured by Toray Industries, Inc.).
Evaluation criteria are as follows.
◎: less than 100 mN / 25 mm. Excellent.
○: not less than 100 mN / 25 mm and less than 200 mN / 25 mm. Good.
Δ: 200 mN / 25 mm or more and 300 mN / 25 mm. Practical use possible.
X: more than 300 mN / 25 mm. Not practical.

(Adhesive Contamination)
The contamination from the 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. Evaluation criteria are as follows.
○: no pollution is observed at all. Good.
Δ: slight cloudiness observed Practical use possible.
X: Clear cloudiness is observed. Not practical.

(Base material adhesion)
The obtained adhesive sheet was prepared in a size of 50 mm in width and 50 mm in length, and used as a measurement sample. Subsequently, the release sheet was peeled off from the measurement sample in an atmosphere of 23 ° C. and 50% RH, and 11 cuts were made at an interval of 2 mm to the adhesive layer so as to reach the substrate with the knife but not cut. Next, by inserting 11 cuts in the same manner as described above in the direction perpendicular to the cuts, 100 squares were formed in a grid. When the surface was strongly rubbed ten times with a thumb, the number of squares remaining after the adhesive layer was not removed from the substrate was evaluated. Evaluation criteria are as follows.
◎: 100 squares remaining. Excellent.
○: More than 90 squares and less than 100 squares remaining. Good.
Δ: More than 75 squares and less than 90 squares remaining. Practical use possible.
X: The remaining squares are less than 75. Not practical.

(Antistatic property)
The obtained adhesive sheet was prepared in a size of 50 mm in width and 50 mm in length, and used as a measurement sample. Next, peel off the release sheet from the measurement sample under an atmosphere of 23 ° C. and 50% RH, and apply a probe of a surface resistance measuring device (Hiresta-UX MCP-HT800, manufactured by Mitsubishi Chemical Analytech Co., Ltd.) to the adhesive layer. The surface resistance value was evaluated. Evaluation criteria are as follows.
◎: The surface resistance value is less than 1 × 10 8. Excellent.
:: The surface resistance value is 1 × 10 8 or more and 1 × 10 9 or less. Good.
Δ: The surface resistance value is 1 × 10 9 or more and 1 × 10 10 or less. Practical use possible.
X: The surface resistance value is 1 × 10 10 or more. Not practical.

Claims (6)

A urethane polyol (A) having a weight average molecular weight of 100,000 to 500,000, which is a reaction product of a polyol (a) and a polyisocyanate (b), an isocyanate curing agent (B), an antioxidant (D), an antistatic agent ( E) and a multi-functional polyol (F) only contains,
Per 100 parts by mass of urethane polymer (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), polyfunctional polyol (F) 4 to 50 parts by mass,
A pressure-sensitive adhesive in which the polyfunctional polyol (F) has a primary hydroxyl group at the end .   The pressure-sensitive adhesive according to claim 1, wherein the polyfunctional polyol (F) has three or more hydroxyl groups in one molecule.   The pressure-sensitive adhesive according to claim 1, further comprising a plasticizer (C).   The adhesive according to claim 3, comprising 0.1 to 100 parts by mass of the plasticizer (C) with respect to 100 parts by mass of the urethane polyol (A). The adhesive sheet provided with the base material and the adhesion layer which is a hardened | cured material of the adhesive of any one of Claims 1-4 . 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 the pressure-sensitive adhesive sheet according to claim 5 .