JP6521117B1 - Adhesive for surface protection sheet, surface protection sheet, and laminate - Google Patents

Abstract

To provide an adhesive for surface protection, an adhesive sheet and a laminate capable of forming an adhesive layer excellent in adhesion at high temperature, low temperature removability after high temperature aging, and wettability. A polyurethane polyol (A), which is a reaction product of a polyol and an aromatic isocyanate (b), and an isocyanate curing agent (B), wherein 100% by mass of the polyol comprises at least polyether polyol and polyester polyol. It is solved by the adhesive for surface protection sheets which contains 50 mass% or more of polyols (a) which are either. [Selected figure] None

Description

  The present invention relates to a pressure-sensitive adhesive for surface protection sheets.

  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 protection sheet has been widely used to protect optical members used in these display devices from scratches, dust, and the like.

  A pressure-sensitive adhesive containing a urethane resin (hereinafter referred to as a urethane pressure-sensitive adhesive) as a pressure-sensitive adhesive for forming a pressure-sensitive adhesive layer used in a surface protective sheet has wettability and non-stainability to various adherends (optical members etc.) It is used because it is excellent. In addition, the surface protective sheet has a problem that the surface protective sheet floats from the adherend at the time of annealing treatment (high temperature treatment such as 150 ° C.) or peels off at a serious time. Moreover, when peeling a surface protection sheet from a to-be-adhered body after annealing treatment, there existed a problem which adhesive force will rise especially in winter and to damage the to-be-adhered body which is protection object.

  Patent Document 1 discloses a pressure-sensitive adhesive composition comprising a urethane resin (A) having a hydroxyl group, polymethylene polyphenyl polyisocyanate (B), and an organic solvent (C).

  In Patent Document 2, a polyurethane resin (A) having a hydroxyl value with a primary hydroxyl group at the end, a polyfunctional isocyanate compound (B), a polyalkylene glycol compound, an epoxy compound and a phosphoric acid ester compound are selected. Disclosed is a removable urethane pressure-sensitive adhesive composition containing at least one kind of (C).

JP, 2017-193609, A JP, 2015-007226, A

  However, when a conventional adhesive is intended to protect an ITO (indium tin oxide) film, the adhesive layer spreads on the ITO surface at the time of the annealing treatment at high temperature to form a strong molecular bond, and then under normal temperature or low temperature. When peeling is performed, the adhesive force is much greater than that before the treatment, and the optical member to be protected may be damaged or the optical member may be contaminated due to the migration of the adhesive component.

  An object of the present invention is to provide a surface protection pressure-sensitive adhesive, a pressure-sensitive adhesive sheet, and a laminate capable of forming a pressure-sensitive adhesive layer excellent in adhesion at high temperature, low temperature removability after high temperature aging, and wettability.

  As a result of extensive studies to solve the above-mentioned problems, the present inventors have found that by using a compound having a specific structure as a polyol and an isocyanate curing agent for constructing a polyurethane polyol, respectively. It is found that it is possible to solve the problems, and the present invention is made based on this finding.

  That is, the pressure-sensitive adhesive for a surface protection sheet of the present invention comprises a polyurethane polyol (A) which is a reaction product of a polyol and an aromatic isocyanate (b), and an isocyanate curing agent (B). It is characterized by containing 50 mass% or more of the polyol (a) which is at least any one of a polyether polyol and a polyester polyol.

  ADVANTAGE OF THE INVENTION According to said invention, the adhesive agent for surface protection sheets which can form the adhesion layer which is excellent in adhesiveness at the time of high temperature, low temperature removability after high temperature aging, and wettability can be provided, a surface protection sheet, and a laminated body.

Terms are defined prior to the description of the invention. In the present specification, the adherend refers to a partner to which the surface protective sheet is attached.
In the present specification, "tape", "film" and "sheet" are synonymous.

  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.

<< Adhesive for surface protection sheet >>
The pressure-sensitive adhesive for a surface protection sheet of the present invention comprises a polyurethane polyol (A) which is a reaction product of a polyol and an aromatic isocyanate (b), and an isocyanate curing agent (B), in 100% by weight of the polyol It contains 50% by weight or more of a polyol (a) which is at least one of a polyether polyol and a polyester polyol.

  The pressure-sensitive adhesive of the present specification suppresses floating and peeling during high-temperature treatment such as annealing treatment by using polyurethane polyol (A) having an aromatic isocyanate site as a pressure-sensitive adhesive for surface protection sheet, and then low temperature environment Also when peeling off below, it can peel off easily.

The pressure-sensitive adhesive for a surface protection sheet of the present invention 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), 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, it can use for all members, such as window glass, LED, a vehicle, wiring, etc., and a laminated body other than a display, for example. It can also be used for protection during the manufacturing process of parts, as well as for products after manufacture.

(Polyurethane polyol (A))
The polyurethane polyol (A) is obtained by subjecting a polyol containing 50% by weight or more of a polyol (a) which is at least one of a polyether polyol and a polyester polyol to a urethanization reaction of one or more aromatic polyisocyanates (b) Reaction product.
At the time of reaction, the isocyanate group (isocyanato group) of the aromatic polyisocyanate (b) is used at a molar ratio (NCO / OH ratio) which is smaller than that of the hydroxyl group of the polyol. Thereby, a polyurethane polyol is obtained.
The aromatic polyisocyanate (b) is preferably a bifunctional isocyanate (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.

In the production of the polyurethane polyol, a catalyst is preferably used to accelerate the reaction, and a solvent can be used if necessary.
The polyurethane polyols (A) can be used alone or in combination of two or more.

The weight average molecular weight (Mw) of the polyurethane polyol (A) is preferably 100,000 to 500,000, more preferably 100,000 to 400,000, further preferably 150,000 to 400,000, and particularly preferably 150,000 to 300,000. . The heat resistance and productivity can be improved by adjusting the weight average molecular weight (Mw) to the above range.
In addition, a weight average molecular weight (Mw) is a weight average molecular weight of polystyrene conversion calculated | required by gel permeation chromatography (GPC) measurement.

<Polyol>
The polyol is a compound having two or more hydroxyl groups, and the adhesive for a surface protective sheet of the present invention contains 50% by mass or more of a polyol (a) which is at least one of a polyether polyol and a polyester polyol.

The content of the polyol (a) in 100% by mass of the polyol is 50% by mass or more and 100% by mass or less, preferably 60% by mass or more and 95% by mass or less, more preferably 70% by mass or more and 90% by mass or less It is.
When the content of the polyol (a) is 50% by mass or more, the adhesive is excellent in wettability, and by being 100% by mass or less, an adhesive having excellent high-temperature adhesiveness can be obtained.
That is, when the polyurethane polyol is a reaction product with the aromatic isocyanate (b) because the polyol (a) is the main component in the entire polyol, the obtained pressure-sensitive adhesive exhibits adhesion at high temperature , It can be excellent in low temperature removability after high temperature aging and wettability.

  Moreover, as a polyol (a), when containing polyether polyol and 2 or more types of polyester polyols, the total content of these should just be 50 mass% or more.

Although a polyether polyol and a polyester polyol may be used alone, respectively, it is preferable to use them together as it is easy to adjust the cohesion and adhesion of the adhesive layer.
When the polyether polyol and the polyester polyol are used in combination, the polyester polyol is 5 to 100 parts by mass with respect to 100 parts by mass of the polyether polyol from the viewpoint of the balance of the cohesion and adhesion of the adhesive layer. Preferably, it is 10 to 50 parts by mass.

[Polyol (a)]
The polyol (a) is at least one of a polyether polyol and a polyester polyol, and a polyether polyol and a polyester polyol may be used in combination.
More preferably, it is a polyether polyol.

When using one type of polyether polyol or polyester polyol, the polyol (a) is preferably a polyol having three or more hydroxyl groups, from the viewpoint of the balance of the cohesion and adhesion of the adhesive layer. When using 2 or more types of polyols, it is preferable to use together the polyol which has 2 hydroxyl groups, and the polyol which has 3 or more hydroxyl groups. When using together the polyol which has two hydroxyl groups, and the polyol which has three or more, it is preferable that the polyol which has two with respect to 100 mass parts of polyols which have three or more hydroxyl groups is 20-100 mass parts , More preferably, it is 20 to 50 parts by mass.
Moreover, when using together the polyol which has three or more hydroxyl groups, it is preferable to set polyisocyanate (b) and a polyol to NCO / OH ratio (molar ratio) 0.80 or less. When the NCO / OH ratio (molar ratio) is greater than 0.80, gelation occurs locally depending on the polyol and catalyst used in combination, particularly when using a polyol having three hydroxyl groups, and it is detected as foreign matter on the coated surface and the yield May decrease. When the NCO / OH ratio (molar ratio) is 0.40 or more, the weight average molecular weight of the urethane polyol (A) can be easily increased, and heat resistance can be imparted.

  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-aminoethylethanolamine, isophorone diamine and xylylene diamine; trifunctional active hydrogen-containing compounds such as triethanolamine; tetrafunctional activity such as ethylene diamine and aromatic diamine Examples of the hydrogen-containing compounds include 5-functional active hydrogen-containing compounds such as diethylenetriamine.

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

  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 10,000, more preferably 400 to 8,000, and more preferably 600 to 6, 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 cohesion force of a urethane polyol (A) to a suitable range by making Mn or less into 10,000.

  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.

  In addition, since a polyol (a) may corrode adherends, such as ITO, when acidic functional groups, such as a carboxyl group and a sulfo group, contain, it is preferable to use the polyol which does not have an acidic functional group.

[Other polyols]
As other polyols other than a polyol (a), a polycarbonate polyol, a butadiene type polyol, a castor oil polyol, a polyamide polyol, a polyimide polyol, an acryl polyol etc. can be used, for example.

<Aromatic polyisocyanate (b)>
The aromatic polyisocyanate (b) is not limited as long as it is a compound having an aromatic ring and two or more isocyanate groups in one molecule. Among them, a bifunctional isocyanate (also referred to as a diisocyanate) having two isocyanate groups in one molecule is preferable as the aromatic polyisocyanate (b).
As aromatic polyisocyanate (b), 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, ω, ω′-diisocyanate-1,3-dimethylbenzene, ω, ω′-diisocyanate-1, 4-dimethylbenzene, ω, ω′-diisocyanate-1, 4-diethylbenzene Emissions, 1,4-tetramethylxylylene diisocyanate, and 1,3-tetramethyl xylylene diisocyanate isocyanate.

  In addition, it may be triisocyanate modified with diisocyanate. Examples of the triisocyanate include trimethylolpropane adduct, biuret, and trimer of the above diisocyanate (the trimer includes an isocyanurate ring).

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

  The aromatic polyisocyanates (b) may 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.

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

  The catalyst is particularly preferable in that tin-based compounds have little reaction rate improvement and little coloration.

  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 aromatic 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, ketone solvents, ester solvents and the like are preferable from the viewpoint of the solubility of the aromatic polyisocyanate (b), and hydrocarbon solvents and the like are preferably used in combination from the viewpoint of 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 and solution polymerization.
The procedure of the manufacturing method is, for example,
(Procedure 1) A flask containing one or more polyols (a), one or more aromatic polyisocyanates (b), optionally, one or more catalysts, and optionally, one or more solvents. Steps to prepare for;
(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 aromatic polyisocyanates (b B) adding dropwise).
(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 procedure in which one or more aromatic polyisocyanates (b) are added dropwise, and then an excess of one or more polyols (a) is added dropwise thereafter.
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 aromatic polyisocyanate (b) and the hydroxyl group (OH) of the polyol (y) at the time of producing the urethane polyol (A) have a molar ratio of NCO / OH of 0.4 to 0. 95 is preferable, 0.4 to 0.90 is more preferable, and 0.5 to 0.80 is more preferable. 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 heat resistance 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.

(Isocyanate curing agent (B))
The isocyanate curing agent (B) is a known compound having a plurality of isocyanate groups.
As the isocyanate curing agent (B), the above-mentioned aromatic polyisocyanate (b) may be used, and isocyanate compounds other than the aromatic polyisocyanate (b), for example, aliphatic polyisocyanate and alicyclic polyisocyanate, and These trimethylol propane adducts, burettes thereof, or trifunctional isocyanates which are trimers thereof may be used.
In particular, it is preferable to use an aromatic polyisocyanate, and in particular, an aromatic polyisocyanate having three or more isocyanate groups in the molecule is preferable because of its excellent low-temperature removability. Moreover, it is preferable to use an aliphatic polyisocyanate having three or more isocyanate groups because of excellent wettability.

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

  1 mass part or more and 20 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), 1-15 mass parts is more preferable, 1.5-10 mass parts Further preferred is 2.0 to 5 parts by mass. When the content of the isocyanate curing agent (B) is in this range, the wettability and the high-temperature adhesion become good, and an appropriate adhesion and cohesion can be easily obtained.

(Plasticizer (C))
The pressure-sensitive adhesive of the present invention can further contain a plasticizer (C). By including the plasticizer (C), the wettability of the adhesive layer to the adherend is further improved. The plasticizer (C) is preferably an ester compound of a fatty acid having 4 to 18 carbon atoms, a phosphate ester, or the like, from the viewpoint of compatibility with other components.

  The ester compound of a fatty acid having 4 to 18 carbon atoms is, for example, an ester of a monobasic acid or polybasic acid having 4 to 18 carbon atoms and a branched alcohol having 18 or less carbon atoms, an unsaturated fatty acid having 14 to 18 carbon atoms or a branched chain. Esters of acids and alcohols having a valency of 4 or less, esters of monobasic acids or polybasic acids having 4 to 18 carbon atoms or esters of polyalkylene glycols, fatty acid esters in which unsaturated sites are epoxidized with peroxides, etc. .

  Examples of esters of monobasic acids or polybasic acids having 4 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, and triisocetyl trimellitate.

  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.

  As esters of monobasic acids or polybasic acids having 4 to 18 carbon atoms and polybasic acids with polyalkylene glycols, polyethylene glycol dihexylate, polyethylene glycol di-2-ethylhexylate, polyethylene glycol dilaurate, polyethylene glycol dioleate, and adipic acid Dipolyethylene glycol methyl ether etc. are 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.

  The number average molecular weight (Mn) of the plasticizer (C) is preferably 300 to 1000, more preferably 300 to 900, and still more preferably 350 to 850, from the viewpoint of improving the wetting rate and the like.

  0.1-100 mass parts is preferable with respect to 100 mass parts of polyurethane polyols (A), as for the compounding quantity of a plasticizer (C), 1-80 mass parts is more preferable, and 5-60 mass parts is more preferable. When the plasticizer (C) is blended in an appropriate amount, the wettability is further improved.

(Antioxidant (D))
The pressure-sensitive adhesive of the present invention can further contain an antioxidant (D). When the antioxidant (D) is contained, the thermal decomposition of the crosslinked network of the polyurethane 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.
The antioxidant is preferably a radical chain inhibitor such as a phenol type antioxidant and an amine type antioxidant, and a sulfur type antioxidant or a phosphorus type antioxidant. Phenolic antioxidants are more 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.

  0.01-10 mass parts is preferable with respect to 100 mass parts of polyurethane polyols (A), and, as for the compounding quantity of antioxidant (D), 0.1-5 mass parts is more preferable, 0.3-5 mass Parts are more preferred.

(Antistatic agent (E))
The pressure-sensitive adhesive of the present invention can further contain 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.
The present invention comprises a polyurethane polyol (A) which is a reaction product of a polyol and an aromatic isocyanate (b), and an isocyanate curing agent (B), wherein 100% by mass of the polyol comprises at least polyether polyol and polyester polyol. By using a pressure-sensitive adhesive containing 50% by mass or more of the polyol (a), which is either, in combination with an antistatic agent, not only the antistatic property but also the wettability can be further improved. In using for a sheet for sheets, it can be considered as a more excellent adhesive.

  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, imidazolium ion, pyridinium ion, ammonium ion and 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 a pyrrolidinium salt, a phosphonium salt, a sulfonium salt or the like can be appropriately used.

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

  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 type includes, for example, glycerin fatty acid ester, polyoxyalkylene alkyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene alkylamine, polyoxyethylene alkylamine fatty acid ester, fatty acid diethanolamide, polyether ester amide type And ethylene oxide-epichlorohydrin type and polyether ester type.
The anionic type includes, for example, alkyl sulfonates, alkyl benzene sulfonates, alkyl phosphates, and polystyrene sulfonates.
The cationic type includes, for example, tetraalkyl ammonium salt, trialkyl benzyl ammonium salt, and quaternary ammonium base-containing acrylate polymer type.
Amphoteric types include, for example, amino acid type amphoteric surfactants such as alkyl betaines and alkyl imidazolium betaines, higher alkyl amino propionates, betaine type amphoteric surfactants such as higher alkyl dimethyl betaines and higher alkyl dihydroxyethyl betaines, etc. Can be mentioned.

  When the antistatic agent (E) is liquid at 25 ° C., the surface orientation is excellent as compared to when it is solid, and thus, it is easy to express better antistatic properties.

  When the antistatic agent (E) is solid at 25 ° C., a part thereof is present as an aggregate in the pressure-sensitive adhesive layer and acts as a stress relaxation site as compared with the liquid, and therefore, good substrate adhesion is obtained. It is easy to express.

  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 polyurethane polyols (A), and, as for the compounding quantity of antistatic agent (E), 0.03-2 mass parts is more preferable, 0.06-1 mass. Parts are more preferred. When the amount is 0.01 parts by mass or more, antistatic performance can be exhibited, and when the amount is 3 parts by mass or less, the contamination of the adherend can be reduced.

(solvent)
As a solvent, although the solvent which can be used in the case of manufacture of the above-mentioned polyurethane polyol (A) can be used, the ester system, the ketone system, the hydrocarbon solvent etc. whose boiling point is 120 degrees C or less are preferable. The solvents may be used alone or in combination of two or more.

(Optional ingredient)
The pressure-sensitive adhesive of the present specification can contain optional components as needed as long as the problems can be solved. Optional components include, for example, resins, fillers, metal powders, pigments, foils, softeners, UV absorbers, light stabilizers, surface lubricants, leveling agents, corrosion inhibitors, heat stabilizers, polymerization inhibitors, Defoamers, lubricants and the like can be mentioned.

  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.

  Depending on the protection target, it may be preferable to transmit ultraviolet light to form a UV-curable film, depending on the protection target. Under such circumstances, it is preferred that the present invention does not contain a UV absorber.

  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).

<< surface protection sheet >>
The surface protection sheet of the present invention is a pressure-sensitive adhesive sheet used to protect an optical member used in a display device from adhesion of a scratch or dust, and is a cured product of a substrate and a pressure-sensitive adhesive for surface protection sheet And an adhesive layer which is 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.

  The surface protection sheet can use the well-known release sheet in which well-known release processes, such as a silicone type release agent, were performed to surfaces, such as a plastics or paper.

  The method for producing a surface protective sheet is, for example, applying an adhesive for surface protective sheet on the surface of a substrate to form a coated layer, and then drying and curing the coated layer to form an adhesive layer The method is mentioned. 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 invention comprises an optical member provided with a layer selected from the group consisting of a transparent conductive film, glass, an acrylic plate, a polycarbonate plate and an olefin plate, and an adhesive sheet. The transparent conductive film refers to a film in which a conductive layer such as ITO is thin-film deposited to about 0.1 to 0.3 μm on the surface of a transparent film such as polyethylene terephthalate (PET).

  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 measuring method of weight average molecular weights (Mw) and number average molecular weights (Mn), such as a polyol and polyurethane polyol, is as follows.

[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

[Synthesis Example of Polyurethane Polyol (A)]
Synthesis Example 1
A 4-neck flask equipped with a stirrer, a reflux condenser, a nitrogen inlet, a thermometer, and a dropping funnel: 1000 parts of Adeka polyether G-1500 (trifunctional polyether polyol, manufactured by ADEKA), 160 parts of diphenylmethane diisocyanate, 233 parts of MEK Then, 540 parts of toluene, 0.3 parts of dibutyltin dilaurate as a catalyst and 0.1 parts of tin 2-ethylhexanoate were added thereto, and the temperature was gradually raised to 80 ° C. to carry out a reaction for 2 hours. The reaction was terminated after confirming that the NCO characteristic absorption (2,270 cm ⁻¹ ) of the IR chart disappeared. The weight average molecular weight (Mw) of this polyurethane polyol (A1) was 178,000.

(Composition examples 2 to 17)
A polyurethane polyol (A2 to A2) was prepared according to Synthesis Examples 2 to 14, respectively, by manufacturing in the same manner as in Synthesis Example 1 except that the raw materials and compounding amounts (parts by mass) of Synthesis Example 1 were changed as shown in Table 1. A14), and polyurethane polyols (A'1 to A'3) were obtained.

[material]
The materials used in Tables 1 and 2 are as follows.

<Polyol (a)>
G1500 ("ADECA POLYETHER G-1500", polyether polyol, Mn1500, number of hydroxyl groups 3, secondary hydroxyl group, manufactured by Adeka)
GP 3000 ("Sannix GP-3000", polyether polyol, Mn 3000, number of hydroxyl groups 3, secondary hydroxyl group, manufactured by Sanyo Chemical Industries, Ltd.)
GL 3000 (“Sannix GL-3000”, polyether polyol, Mn 3000, number of hydroxyl groups: 3, primary hydroxyl group, manufactured by Sanyo Chemical Industries, Ltd.)
Exe 5030 ("Exenol 5030", polyether polyol, Mn 5100, number of hydroxyl groups 3, secondary hydroxyl group, manufactured by Asahi Glass Co., Ltd.)
F3010 ("Kuraray polyol F-3010", polyester polyol, Mn 3000, number of hydroxyl groups: 3, primary hydroxyl group, manufactured by Kuraray Co., Ltd.)
PP 1000 (“Sannicks PP-1000”, polyoxypropylene glycol, Mn 1000, hydroxyl number 2, secondary hydroxyl group, Sanyo Chemical Industries, Ltd.)
P1010 ("Kuraray polyol P-1010", polyester polyol, Mn 1000, hydroxyl number 2, primary hydroxyl group, manufactured by Kuraray Co., Ltd.)

<Polyol (a '); Polyol other than Polyol (a)>
T5652 (“Duranol T5652”, polycarbonate diol, Mn 2000, number of hydroxyl groups: 2, primary hydroxyl group, manufactured by Asahi Kasei Corporation)
EG ("ethylene glycol", ethylene glycol, Mn 62.1, number of hydroxyl groups 2, primary hydroxyl group, manufactured by Mitsubishi Chemical Corporation)
BG ("14BG", 1,4-butanediol, Mn 90.1, two hydroxyl groups, primary hydroxyl group, manufactured by Mitsubishi Chemical Corporation)

<Aromatic polyisocyanate (b)>
MDI ("Millionate MT", diphenylmethane diisocyanate, Mn 250, manufactured by Tosoh Corporation),
TDI ("Coronato T-80", tolylene diisocyanate, Mn 174, manufactured by Tosoh Corporation),
<Polyisocyanate (b ');
Polyisocyanates other than aromatic polyisocyanate (b)>
HDI ("Desmodur H", hexamethylene diisocyanate, Mn 169, manufactured by Sumika Kovestro Urethane Co., Ltd.),

<Isocyanate curing agent (B)>
(B1): TDI adduct ("Desmodur L75", trimethylolpropane adduct of tolylene diisocyanate, manufactured by Sumika Kobethurourethane Co., Ltd.)
(B2): HDI adduct ("Sumidur HT", trimethylolpropane adduct of hexamethylene diisocyanate, manufactured by Sumika Kobe Sorourethane Co., Ltd.)

<Antioxidant (D)>
(D1): Irg1010 ("Irganox 1010", pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], phenolic antioxidant, manufactured by BASF)

<Antistatic agent (E)>
(E1): TFSI ammonium salt (tri-n-butyl methyl ammonium bis trifluoromethane sulfone imide)

  The polyol [a] content [%] in Tables 1 and 2 is the content [%] of the polyol (a) which is at least one of polyether polyol and polyester polyol in 100% by mass of all polyols. is there.

Example 1
100 parts of the urethane polyol (A1) obtained in Synthesis Example 1, 2 parts of an isocyanate curing agent (B1), 0.5 parts of an antioxidant (D1), and 60 parts of ethyl acetate as a solvent are blended and stirred with a disper The pressure-sensitive adhesive was obtained. 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 laminated, and further, it was aged for 1 week under conditions of 23 ° C. and 50% RH to obtain a sheet for surface protection.

(Examples 2 to 23, Comparative Examples 1 to 3)
The pressure-sensitive adhesive of Examples 2 to 23 and Comparative Examples 1 to 3 is carried out in the same manner as in Example 1 except that the materials and the compounding ratio (parts by mass) of Example 1 are changed as shown in Tables 3 to 6 And a sheet for surface protection were obtained.
However, Examples 1, 2, 8, 12, 14, 16, 20, 21, 22, and 23 are reference examples.

[Evaluation items and evaluation method]
Evaluation items and evaluation methods of the obtained pressure-sensitive adhesive and sheet for surface protection are as follows. The results are shown in Tables 3 to 6.

(Wetability)
The obtained sheet for surface protection was prepared in a size of 50 mm in width and 100 mm in length, and used as a measurement sample. Subsequently, after leaving for 30 minutes in 23 degreeC-50% RH atmosphere, the peeling sheet was peeled from the measurement sample. The center portion of the exposed adhesive layer was brought into contact with the glass plate while holding the both ends of the surface protective sheet with both hands, and then the hands were released. The wettability of the adhesive layer was evaluated by measuring the time until the whole adhesive layer adheres to the ITO film (“Terate TCF”, manufactured by Oike Kogyo Co., Ltd.) by the weight of the measurement sample. Evaluation criteria are as follows.
Since the wettability (affinity) with respect to ITO is so favorable that time until it adheres with an ITO film is short, an ITO film can be favorably protected by the manufacturing process using an ITO film.

◎: Less than 3 seconds until close contact, excellent.
○: 3 seconds or more and less than 4 seconds until adhesion is good.
Fair: 4 seconds or more and less than 5 seconds until close contact, practical use possible.
X: Not practical for more than 5 seconds until close contact.

(High temperature adhesion)
The obtained sheet for surface protection was prepared in a size of 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 attached to the ITO film, and the 2 kg roll was reciprocated once for pressure bonding. Thereafter, it was left at 150 ° C. for 1 hour. Then, using a tensile tester (manufactured by Tester Sangyo Co., Ltd.), the adhesive strength was measured under an environment of 80 ° C., a peeling speed of 300 mm / min, and a peeling angle of 180 °. Evaluation criteria are as follows.
It can be said that floating and peeling at the time of annealing can be suppressed as the high temperature adhesive strength is higher.

◎: 100 mN / 25 mm or more, excellent.
○: 50 mN / 25 mm or more, less than 100 mN / 25 mm, good.
Δ: 20 mN / 25 mm or more, 50 mN / 25 mm or less, practical use possible.
X: Less than 20 mN / 25 mm, not practical.

(Low temperature re-peeling)
The obtained sheet for surface protection was prepared in a size of 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 attached to the ITO film, and the 2 kg roll was reciprocated once for pressure bonding. Thereafter, it was left at 150 ° C. for 1 hour. Next, after air cooling in an atmosphere of 23 ° C. and 50% RH for 30 minutes, the adhesion was measured under a 10 ° C. environment, a peeling speed of 300 mm / min, and a peeling angle of 180 ° using a tensile tester. Evaluation criteria are as follows.
It shows that the lower the adhesive strength, the easier the re-peeling.

◎: Less than 100 mN / 25 mm, excellent.
○: 100 mN / 25 mm or more, less than 200 mN / 25 mm, good.
Δ: 200 mN / 25 mm or more and less than 300 mN / 25 mm, practical use possible.
X: Not practical for 300 mN / 25 mm or more.

From the results of Tables 3 to 6, it is found that the surface protective sheet formed using the pressure sensitive adhesive for surface protective sheet of the present invention is excellent in adhesion at high temperature, low temperature removability after high temperature aging, and wettability. Was confirmed.
Above all, when the weight average molecular weight of the polyurethane polyol (A) is 100,000 or more, both high temperature adhesive strength and low temperature removability have been achieved.
Moreover, when it contains 1-20 mass parts of isocyanate curing agents (B) with respect to 100 mass parts of polyurethane polyols (A), coexistence of wettability and high temperature adhesive force was made.

  Moreover, thereby, the laminated body provided with the surface protection sheet of this invention and an optical member was not received to the influence of a seasonal fluctuation, but it has confirmed that it was excellent in the yield.

Claims (7)

A polyurethane polyol (A) which is a reaction product of a polyol and an aromatic isocyanate (b), and an isocyanate curing agent (B),
More than 80% by mass of the polyol (a), which is at least one of a polyether polyol and a polyester polyol, is contained in 100% by mass of the polyol,
The polyol (a) contains a polyol having three or more hydroxyl groups, and the polyol having two hydroxyl groups is 50 parts by mass or less with respect to 100 parts by mass of the polyol having three or more hydroxyl groups,
The aromatic isocyanate (b) is diphenylmethane diisocyanate,
The content of the isocyanate curing agent (B) is 2.0 parts by mass or more with respect to 100 parts by mass of the polyurethane polyol (A),
Pressure-sensitive adhesive for surface protection sheet (provided that at least one selected from the group consisting of an organic acid (B-1), an acidic phosphoric acid ester compound (B-2), and an organic acid anhydride (B-3) Excluding the case of containing) .

Organic acid (B-1) Organic acid other than acidic phosphoric acid ester compound (B-2)
Organic acid (B-2) At least one selected from the group consisting of acidic phosphoric acid ester compounds represented by the following chemical formulas (I), (II) and (III)

In the above formula (I),
R ¹ and R ² are each a hydrogen atom, a hydrocarbon group or an aryl group,
R ¹ and R ² may be the same or different,
At least one of R ¹ and R ² is a hydrocarbon group or an aryl group.

In the above chemical formulas (II) and (III),
R ³ and R ⁴ are each a hydrogen atom, a hydrocarbon group or an aryl group,
R ³ and R ⁴ may be the same or different,
At least one of R ³ and R ⁴ is a hydrocarbon group or an aryl group,
AO is an alkylene oxide group, and each AO may be the same or different,
n represents an integer of 1 or more, and each n may be the same or different.   The pressure-sensitive adhesive according to claim 1, wherein the weight average molecular weight of the polyurethane polyol (A) is 100,000 to 500,000.   The pressure-sensitive adhesive according to claim 1 or 2, wherein the isocyanate curing agent (B) is an aromatic isocyanate.   The adhesive for surface protection sheets of any one of Claims 1-3 which contain 1-20 mass parts of said isocyanate curing agents (B) with respect to 100 mass parts of said polyurethane polyols (A).   Furthermore, the adhesive for surface protection sheets of any one of Claims 1-4 containing an antistatic agent.   The surface protection sheet provided with the adhesion layer which is a hardened | cured material of a base material and the adhesive for surface protection sheets of any one of Claims 1-5. A laminate comprising an optical member and the surface protective sheet according to claim 6.