JP2018131500A - Pressure sensitive adhesive and pressure sensitive adhesive sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure sensitive adhesive capable of forming a pressure sensitive adhesive layer that exhibits good wettability, good bendability, good removability, and little adherend contamination after removal.SOLUTION: The pressure sensitive adhesive comprises: a polyurethane polyol (A), which is a reaction product of polyisocyanates (y) and polyols (x) including at least a trifunctional polyol (x2); and a polyfunctional isocyanate compound (B). The at least trifunctional polyol (x2) has one or more ethyleneoxy groups in each molecule, and includes at least a trifunctional polyether polyol (x2) having a number-average molecular weight of more than 3,000. The polyisocyanates (y) include a difunctional isocyanate compound (y1).SELECTED DRAWING: None

Description

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

Conventionally, pressure-sensitive adhesive sheets having a pressure-sensitive adhesive layer formed on a base material sheet have been widely used as surface protective sheets for various members. Examples of the pressure sensitive adhesive include acrylic pressure sensitive adhesive, silicone pressure sensitive adhesive, and urethane pressure sensitive adhesive. Acrylic pressure-sensitive adhesives are excellent in adhesive strength, but because of their strong adhesive strength, re-peelability after being attached to an adherend is not good. In particular, after a lapse of time in a high temperature and high humidity environment, the removability is further lowered due to an increase in adhesive force, and the adherend tends to cause adherence contamination in which the adhesive component remains on the surface of the adherend after re-peeling. is there. Silicone pressure-sensitive adhesives are liable to cause adherend contamination, and there is a risk that silicone resins having a relatively low molecular weight will volatilize and adsorb on the surface of equipment such as electronic devices. On the other hand, the urethane-based pressure-sensitive adhesive has good adhesion to the adherend and is relatively excellent in removability, and the urethane-based resin is less likely to volatilize.
In this specification, the “pressure-sensitive adhesive” is a pressure-sensitive adhesive having removability (removable pressure-sensitive adhesive), and the “pressure-sensitive adhesive sheet” is a pressure-sensitive adhesive sheet having re-peelability (removable pressure-sensitive adhesive sheet).

A flat panel display such as a liquid crystal display (LCD) and an organic electroluminescence display (OELD), and a touch panel display in which such a flat panel display and a touch panel are combined include a television (TV), a personal computer (PC), a mobile phone, and Widely used in electronic devices such as portable information terminals.
Urethane pressure-sensitive adhesive sheets are flat panel displays and touch panel displays, and substrates manufactured or used in these manufacturing processes (glass substrates, and ITO / glass substrates on which ITO (indium tin oxide) films are formed on glass substrates). Etc.) and a surface protective sheet for optical members and the like.

  The pressure-sensitive adhesive layer preferably has good wettability with respect to an adherend such as glass, and it is preferable that air bubbles are not involved in the sticking interface when the pressure-sensitive adhesive sheet is stuck to the adherend. In the urethane-based pressure-sensitive adhesive, a plasticizer may be added in order to improve wettability. However, when the amount of the plasticizer added is large, there is a risk that adherend contamination will occur where the adhesive component remains on the surface of the adherend after re-peeling. Therefore, it is preferable that the addition amount of the plasticizer is small, and it is more preferable that there is no addition amount of the plasticizer. It is preferable that the urethane-based pressure-sensitive adhesive has good wettability even in a blended composition in which the amount of plasticizer added is small / preferably no plasticizer is added.

  An adhesive sheet may be affixed on the display which has a curved part. Further, a display such as OELD can be made flexible by using a plastic film as a substrate, and the pressure-sensitive adhesive sheet may be bent in a state of being attached to a flexible adherend. In the pressure-sensitive adhesive sheet used for such a use, it is preferable that the pressure-sensitive adhesive layer hardly peels from the adherend and has good curvature.

  When removing the pressure-sensitive adhesive sheet from the adherend, it is preferable that the pressure-sensitive adhesive sheet has good removability so that it can be easily peeled off from the adherend.

  As a method for producing a urethane-based pressure-sensitive adhesive, a method using a polyurethane polyol and a polyfunctional isocyanate compound, which is a reaction product of a polyol and a polyisocyanate, and a reaction between a polyol and a polyfunctional isocyanate compound at one time without using a polyurethane polyol. (One-shot method).

  In general, the pressure-sensitive adhesive layer using a urethane-based pressure-sensitive adhesive obtained by the one-shot method is hard and cannot have good curvature. Also, the surface smoothness of the adhesive layer tends to deteriorate due to curing shrinkage.

  Since it is easy to optimize the adhesive force and cohesive force, a method using a polyurethane polyol is preferred. As the raw material polyol of the polyurethane polyol, a bifunctional polyol and a trifunctional or higher functional polyol can be used in combination. In general, a bifunctional polyol has a two-dimensional crosslinkability and can impart an appropriate flexibility to the pressure-sensitive adhesive layer, and a tri- or higher functional polyol has a three-dimensional crosslinkability and an appropriate hardness in the pressure-sensitive adhesive layer. Can be added. By using these together, it becomes possible to obtain an adhesive layer having suitable cohesive strength and adhesive strength.

Patent Document 1 discloses a urethane prepolymer (A) containing a polyether polyol (a) having an average number of functional groups per molecule of 2.2 to 3.4, a polyisocyanate compound (b), and a catalyst (c). And a urethane-based pressure-sensitive adhesive containing the polyfunctional isocyanate compound (B) (Claim 1).
In Patent Document 1, the polyether polyol (a) is preferably a mixture of a polyether diol and a polyether triol (Claim 3).

Patent Document 2 discloses a urethane resin containing polyurethane resin (A), polyfunctional isocyanate compound (B), and at least one selected from polyalkylene glycol compounds, epoxy compounds and phosphate ester compounds (C). An adhesive is disclosed (claim 1).
Patent Document 2 discloses a synthesis example of a polyurethane polyol in which a bifunctional polyol and a trifunctional or higher functional polyol are used in combination as a raw material polyol for the polyurethane polyol (Synthesis Examples 1 to 5).

  In addition, the code | symbol of the various components in patent documents 1, 2 is describing the code | symbol described in literature as it is, and is unrelated to the code | symbol of the various components used with the adhesive of this invention.

JP 2006-18295 A Japanese Patent Laying-Open No. 2015-7226

In Patent Document 1, the polyether diol is preferably a bifunctional polypropylene glycol (a1), and the polyether triol is a trifunctional polypropylene glycol (a2) (Claim 4, Synthesis Examples 1 to 7). In Synthesis Examples 1 to 7 of Patent Document 1, the number average molecular weight of the polyether diol (a1) is only 1,000, and the number average molecular weight of the polyether triol (a2) is 350 to 3,000. In Examples 1 to 12 of Patent Document 1 using the polyurethane polyols of Synthesis Examples 1 to 7, no wetting agent is used.
According to the knowledge of the present inventor, the urethane-based pressure-sensitive adhesives of Examples 1 to 12 of Patent Document 1 have insufficient wettability, and bubbles are formed at the bonding interface when the pressure-sensitive adhesive sheet is bonded to the adherend. It is easy to involve (see Comparative Example 2 in the section of [Examples] below).

In Patent Document 2, in Synthesis Examples 1 to 3, ADEKA polyether AM-302 (trifunctional polypropylene glycol with terminal ethylene oxide cap, molecular weight 3,000, manufactured by ADEKA) is used as a trifunctional or higher functional polyol. Yes.
According to the knowledge of the present inventors, in the urethane-based adhesives of Examples 1 to 15, 17, and 18 of Patent Document 2 using the polyurethane polyols of Synthesis Examples 1 to 3 and 5, the adhesive having good curving properties. It is difficult to form a layer (see Comparative Example 1 in the section “Examples” below). In these Examples of Patent Document 2, a plasticizer (component (C)) is used to improve wettability, and the adherend remains on the surface of the adherend after re-peeling. There is also a problem of contamination (see Comparative Example 1 in the section “Example” below).

  The present invention has been made in view of the above circumstances, and has good wettability, good curvability, good removability, and less adherend contamination after re-peeling. It aims at providing the adhesive which can form a layer.

The pressure-sensitive adhesive of the present invention is
A polyurethane polyol (A) which is a reaction product of a polyol (x) containing a trifunctional or higher polyol (x2) and a polyisocyanate (y);
A pressure-sensitive adhesive containing a polyfunctional isocyanate compound (B),
The trifunctional or higher functional polyol (x2) has one or more ethyleneoxy (EO) groups in one molecule and the number average molecular weight (Mn) is more than 3,000. _H )
The polyisocyanate (y) contains a bifunctional isocyanate compound (y1).

  The pressure-sensitive adhesive of the present invention is a composition in which a plurality of types of materials including the above components (A) and (B) are blended. In the pressure-sensitive adhesive, a plurality of types of blending components including the components (A) and (B). May not all be clearly present as independent components. That is, the pressure-sensitive adhesive of the present invention may contain a reaction product obtained by partially reacting a plurality of blended components including components (A) and (B).

The pressure-sensitive adhesive sheet of the present invention includes a base sheet and a pressure-sensitive adhesive layer made of a cured product of the pressure-sensitive adhesive of the present invention.
Generally, a sheet-like material is referred to as “tape”, “film”, or “sheet” depending on the thickness and width. In the present specification, these are not particularly distinguished, and the term “sheet” is used as a term representing a concept encompassing them.

  In the present specification, unless otherwise specified, the weight average molecular weight (Mw) and the number average molecular weight (Mn) are polystyrene-converted values determined by gel permeation chromatography (GPC) measurement, and are described later in [Examples]. It can be measured by the method described.

  According to the present invention, it is possible to form an adhesive layer having good wettability, good bendability, good removability, and less adherend adherence after removability. An adhesive can be provided.

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

The pressure-sensitive adhesive of the present invention is
A polyurethane polyol (A) which is a reaction product of a polyol (x) containing a trifunctional or higher polyol (x2) and a polyisocyanate (y);
A polyfunctional isocyanate compound (B),
The trifunctional or higher functional polyol (x2) has one or more ethyleneoxy (EO) groups in one molecule and the number average molecular weight (Mn) is more than 3,000. _H )
Polyisocyanate (y) is a urethane-based pressure-sensitive adhesive containing a bifunctional isocyanate compound (y1).

  Note that the pressure-sensitive adhesive of the present invention can solve the above problems even with a blending composition in which the amount of plasticizer (P) added is small / preferably without the amount of plasticizer (P) added. As long as it does not deviate, a plasticizer (P) may be blended as necessary.

The pressure-sensitive adhesive sheet of the present invention is a urethane-based pressure-sensitive adhesive sheet including a base sheet and a pressure-sensitive adhesive layer made of the cured product of the pressure-sensitive adhesive of the present invention.
The pressure-sensitive adhesive sheet of the present invention can be used in the form of a tape, a label, a seal, a double-sided tape and the like. The pressure-sensitive adhesive sheet of the present invention is suitably used as a surface protective sheet, a cosmetic sheet, a non-slip sheet, and the like.
Flat panel displays such as liquid crystal displays (LCD) and organic electroluminescence displays (OELD), and touch panel displays in which such flat panel displays and touch panels are combined include televisions (TVs), personal computers (PCs), mobile phones, And widely used in electronic devices such as portable information terminals.
The pressure-sensitive adhesive sheet of the present invention includes a flat panel display and a touch panel display (collectively these are also simply referred to as “display”), and a substrate manufactured or used in these manufacturing processes (a glass substrate and ITO on the glass substrate). (ITO / glass substrate or the like on which an (indium tin oxide) film is formed) and a surface protective sheet for optical members and the like.

"Adhesive"
(Polyurethane polyol (A))
The polyurethane polyol (A) is a reaction product obtained by copolymerizing one or more polyols (x) and one or more polyisocyanates (y). One or more polyurethane polyols (A) can be used. The copolymerization reaction can be performed in the presence of a catalyst, if necessary. A solvent can be used in the copolymerization reaction as necessary.

<Polyol (x)>
The polyol (x) contains at least one or more trifunctional or higher functional polyols (x2). Preferably, the polyol (x) includes one or more bifunctional polyols (x1) and one or more trifunctional or higher functional polyols (x2).

  The kind of polyol (x) is not particularly limited, and examples thereof include polyester polyol, polyether polyol, polyacryl polyol, polycaprolactone polyol, polycarbonate polyol, and castor oil-based polyol. Of these, polyester polyols, polyether polyols, and combinations thereof are preferable.

  A well-known thing can be used as a polyester polyol, The compound (esterification thing) obtained by esterification reaction of 1 or more types of polyol components and 1 or more types of acid components is mentioned.

  Examples of the starting polyol component include ethylene glycol (EG), propylene glycol (PG), diethylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, and 3-methyl-1,5-pentane. Diol, 2-butyl-2-ethyl-1,3-propanediol, 2,4-diethyl-1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 2-ethyl-1, 3-hexanediol, 1,8-octanediol, 1,9-nonanediol, 2-methyl-1,8-octanediol, 1,8-decanediol, octadecanediol, glycerin, trimethylolpropane, pentaerythritol, and Examples include hexanetriol.

  Examples of the acid component of the raw material 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, 4,4′-Bifeel Examples thereof include dicarboxylic acids and acid anhydrides thereof.

  As the polyether polyol, a known one can be used, and a compound 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. (Addition polymer).

  Examples of the initiator include a hydroxyl group-containing compound and an amine. Specifically, ethylene glycol (EG), propylene glycol (PG), 1,4-butanediol, neopentyl glycol, butylethylpentanediol, N-aminoethylethanolamine, isophoronediamine, xylylenediamine, and the like 2 Functional initiators; trifunctional initiators such as glycerin, trimethylolpropane, and triethanolamine; tetrafunctional initiators such as pentaerythritol, ethylenediamine, and aromatic diamine; and pentafunctional initiators such as diethylenetriamine.

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

  As the polyether polyol, an alkylene oxide adduct (also referred to as polyoxyalkylene polyol) of an active hydrogen-containing compound is preferable. Among these, bifunctional polyether polyols such as polyethylene glycol (PEG), polypropylene glycol (PPG), and polytetramethylene glycol; trifunctional polyether polyols such as an alkylene oxide adduct of glycerin are preferable.

The number average molecular weight (Mn) of the polyol (x) is not particularly limited, and is preferably 200 to 25,000. When Mn is 200 or more, gelation of the polyurethane polyol (A) is effectively suppressed. When Mn is 25,000 or less, the cohesive force of the polyurethane polyol (A) is suitable.
When using a polyester polyol and / or a polyether polyol as the polyol (x), preferred number average molecular weight (Mn) is as follows.
The number average molecular weight (Mn) of the polyester polyol is preferably 500 to 5,000, more preferably 600 to 4,000, and particularly preferably 800 to 3,000. When Mn is 500 or more, gelation of the polyurethane polyol (A) is effectively suppressed. When Mn is 5,000 or less, the cohesive force of the polyurethane polyol (A) is suitable.
The number average molecular weight (Mn) of the polyether polyol is preferably 500 to 5,000, more preferably 600 to 4,000, and particularly preferably 800 to 3,000. When Mn is 500 or more, gelation of the polyurethane polyol (A) is effectively suppressed. When Mn is 5,000 or less, the cohesive force of the polyurethane polyol (A) is suitable.

As described above, in the present invention, at least one or more trifunctional or higher functional polyols (x2) are used as the polyol (x).
Preferably, one or more bifunctional polyols (x1) and one or more trifunctional or higher functional polyols (x2) are used in combination. In general, the bifunctional polyol (x1) has a two-dimensional crosslinkability and can impart an appropriate flexibility to the adhesive layer, and the trifunctional or higher functional polyol (x2) has a threedimensional crosslinkability. Appropriate hardness can be imparted to the adhesive layer. By using these together, it becomes possible to obtain an adhesive layer having suitable cohesive strength and adhesive strength.

In the present invention, the trifunctional or higher functional polyol (x2) has one or more ethyleneoxy (EO) groups in one molecule and has a number average molecular weight (Mn) of more than 3,000. an ether polyol (x2 _H).

  Conventionally, as described in Patent Documents 1 and 2 mentioned in the section of “Background Art”, a urethane-based pressure-sensitive adhesive in which a bifunctional polyol and a trifunctional polyol containing EO group or not containing EO group are used as a raw material polyol of polyurethane polyol. Is known, but the number average molecular weight (Mn) of the trifunctional polyol used as the raw material polyol is 3,000 or less (Synthesis Examples 1 to 7 and Examples 1 to 12 of Patent Document 1, and Synthesis of Patent Document 2) See Examples 1-3, 5 and Examples 1-15, 17, 18.)

In the present invention, a large trifunctional or more polyether polyols having a number average molecular weight than trifunctional polyol according to Patent Documents _{1,2 (Mn) (x2 H)} . As raw polyol of the polyurethane polyol (A), having an EO group, by using the number-average molecular weight (Mn) of 3,000 greater than trifunctional or more polyether polyols (x2 _H), plasticizer (P) It is possible to provide a pressure-sensitive adhesive capable of forming a pressure-sensitive adhesive layer having good wettability even with a blending composition with a small amount of addition / preferably a plasticizer (P). For example, when adhering to adherends such as glass substrates and ITO / glass substrates, it is possible to form an adhesive layer in which bubbles are unlikely to be involved in the adhering interface.

An adhesive sheet may be affixed on the display which has a curved part. Further, a display such as OELD can be made flexible by using a plastic film as a substrate, and the pressure-sensitive adhesive sheet may be bent in a state of being attached to a flexible adherend. In the pressure-sensitive adhesive sheet used for such a use, it is preferable that the pressure-sensitive adhesive layer hardly peels from the adherend and has good curvature.
As raw polyol of the polyurethane polyol (A), having an EO group, number average molecular weight (Mn) by using 3,000 than a is 3 or more functional polyether polyols (x2 _H), excellent bending resistance An adhesive capable of forming an adhesive layer can be provided. By increasing the molecular weight of the tri- or higher functional polyol than before, the number of cross-linking points of the tri- or higher functional polyol can be reduced. As a result, the adhesive layer exhibits properties close to elastomeric / rubber elasticity, and the adhesive layer It is considered that the bendability is improved.

Further, as the raw polyol of the polyurethane polyol (A), having an EO group, using the number average molecular weight (Mn) is 3,000 than trifunctional or more polyether polyols (x2 _H), the adhesive layer The removability can be improved, and an adhesive layer that can be easily re-peeled can be formed. By using a tri- or higher functional polyol (using relatively large amount), the polymer network of the adhesive layer can be appropriately made three-dimensional, so that the removability of the adhesive layer is considered to be improved.

Wettability, bendable, and the removability improvement effect of increases, the number average molecular weight of trifunctional or more polyether polyols (x2 _{H) (Mn)} is preferably 4,000 or more, more preferably 5, 000 or more, particularly preferably 6,000 or more.
3 the upper limit of the number average molecular weight of di- or higher functional polyether polyol (x2 _{H) (Mn)} is not particularly limited. Since the cohesive strength of the polyurethane polyol (A) is preferred, a number average molecular weight of trifunctional or more polyether polyols (x2 _H) (Mn) is preferably 25,000 or less, more preferably 20,000 or less, Particularly preferred is 15,000 or less, and most preferred is 10,000 or less.

In the present invention, three or more functional polyol (x2) has an EO group, in accordance with the number-average molecular weight (Mn) of 3,000 greater than trifunctional or more polyether polyols (x2 _H), number average A trifunctional or higher functional polyol (x2 _L ) having a molecular weight (Mn) of 3,000 or less can be contained.
As trifunctional or higher polyols (x2), relatively large molecular weight polyether polyol (x2 _H) case where only tends to adhesion of the adhesive layer is increased. By using a polyol (x2 _L ) having a relatively low molecular weight, the adhesive force of the adhesive layer, which increases due to the use of a polyether polyol (x2 _H ) having a relatively high molecular weight, is lowered and adjusted within a suitable range. be able to. The trifunctional or higher functional polyol (x2 _L ) may or may not have an EO group.

  The trifunctional or higher functional polyether polyol having an EO group is a compound (addition polymer) obtained by addition polymerization of one or more oxirane compounds containing ethylene oxide (EO) to the above trifunctional or higher functional initiator. Especially, the compound (addition polymer) obtained by addition-polymerizing 1 or more types of alkylene oxide (AO) containing ethylene oxide (EO) to said trifunctional or more initiator is preferable.

  The tri- or higher functional polyether polyol having an EO group preferably has an EO group at least at the terminal. The tri- or higher functional polyether polyol having an EO group at least at the terminal is a glycerin EO adduct obtained by addition polymerization of one or more ethylene oxides (EO) to glycerin, and one or more propylene oxides (PO) in glycerin. And glycerin PO · EO adduct (also referred to as “glycerin polypropylene glycol-terminated ethylene glycol-modified”) obtained by addition polymerization of styrene and one or more ethylene oxides (EO) in this order.

The bifunctional polyol (x1) is preferably one or more polyols selected from the group consisting of bifunctional polyether polyols and bifunctional polyester polyols.
The bifunctional polyol (x1) preferably contains a bifunctional polyether polyol from the viewpoints of adhesion to the base material and suppression of adherend contamination.

As the bifunctional polyether polyol, a bifunctional polyether polyol having an EO group is preferable in terms of more effectively suppressing adherend contamination.
The bifunctional polyether polyol having an EO group is a compound (addition polymer) obtained by addition polymerization of one or more oxirane compounds containing ethylene oxide (EO) to the above bifunctional initiator. Among these, polyalkylene glycols obtained by addition polymerization of one or more alkylene oxides (AO) containing ethylene oxide (EO) to the above bifunctional initiator are preferable. The higher the EO group content in the polyalkylene glycol, the better. Polyethylene glycol (PEG) is particularly preferred as the bifunctional polyether polyol having an EO group because of the high content of EO groups. That is, the bifunctional polyether polyol having one or more EO groups preferably contains PEG. The upper limit of the amount of EO groups in the tri- or higher functional polyether polyol having an EO group is not particularly limited, and is preferably 50% by mass in the molecular weight of the polyol.
The number average molecular weight (Mn) of the bifunctional polyol (x1) is preferably 200 to 6,000, more preferably 200 to 4,000, and particularly preferably 200 to 2,000.

From the viewpoint of the balance between cohesive strength and adhesive strength,
When the total amount of polyol (x) is 100 parts by mass,
The amount of the bifunctional polyol (x1) is preferably 0 to 90 parts by mass, and the amount of the trifunctional or higher functional polyol (x2) is preferably 100 to 10 parts by mass,
More preferably, the amount of the bifunctional polyol (x1) is 5 to 70 parts by mass, and the amount of the trifunctional or higher functional polyol (x2) is 95 to 30 parts by mass.
It is particularly preferable that the amount of the bifunctional polyol (x1) is 10 to 50 parts by mass and the amount of the trifunctional or higher functional polyol (x2) is 90 to 50 parts by mass.

From the viewpoint of the balance of cohesive strength, adhesive strength, wettability, curvature, and removability,
When the total amount of polyol (x) is 100 parts by mass,
The amount of bifunctional polyol (x1) is 0 to 90 parts by weight, 3 amounts of tri- or higher functional polyether polyol (x2 _H) is 100 to 5 parts by weight, 3 amounts of di- or higher functional polyols (x2 _L) Is preferably 0 to 50 parts by mass,
When the total amount of polyol (x) is 100 parts by mass,
The amount of bifunctional polyol (x1) is 2 to 70 parts by weight, 3 amounts of tri- or higher functional polyether polyol (x2 _H) is 98 to 25 parts by weight, 3 amounts of di- or higher functional polyols (x2 _L) Is more preferably 0 to 40 parts by mass,
When the total amount of polyol (x) is 100 parts by mass,
The amount of bifunctional polyol (x1) is from 5 to 50 parts by weight, 3 amounts of tri- or higher functional polyether polyol (x2 _H) is 95 to 50 parts by weight, 3 amounts of di- or higher functional polyols (x2 _L) Is particularly preferably 0 to 30 parts by mass.
In addition, it is preferable that the amount of the trifunctional or higher functional polyol (x2) is more than the amount of the bifunctional polyol (x1). This further increases the elastomeric properties of the adhesive layer.

<Polyisocyanate (y)>
A well-known thing can be used as a polyisocyanate compound (y), and aromatic polyisocyanate, aliphatic polyisocyanate, araliphatic polyisocyanate, alicyclic polyisocyanate, etc. are mentioned.

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

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

  Examples of the araliphatic polyisocyanate include ω, ω′-diisocyanate-1,3-dimethylbenzene, ω, ω′-diisocyanate-1,4-dimethylbenzene, ω, ω′-diisocyanate-1,4-diethylbenzene. 1,4-tetramethylxylylene diisocyanate, 1,3-tetramethylxylylene diisocyanate, and the like.

  Examples of the alicyclic polyisocyanate include 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate, 1,3-cyclopentane diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, and methyl-2. , 4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 4,4′-methylene bis (cyclohexyl isocyanate), 1,4-bis (isocyanate methyl) cyclohexane, 1,4-bis (isocyanate methyl) cyclohexane, etc. Can be mentioned.

In addition, as the polyisocyanate, an isocyanate prepolymer may be used. The isocyanate prepolymer is obtained by dipolymerizing diisocyanate as a raw material so that the monomer content is 1% or less. Examples of the isocyanate prepolymer include adducts, burettes, and isocyanurates.
An adduct is an adduct of diisocyanate and trimethylolpropane (CH ₃ —CH ₂ —C (CH ₂ —OH) ₃ ). The burette body is a reaction product of diisocyanate and water or a tertiary alcohol. The isocyanurate is a diisocyanate trimer (this trimer contains an isocyanurate ring).

  As the polyisocyanate (y), 4,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate, 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate (isophorone diisocyanate) and the like are preferable.

  In the polymerization of the urethane prepolymer (A), the blending ratio of the polyol (x) and the polyisocyanate (y) is preferably set so that the number of moles of hydroxyl groups exceeds the number of moles of isocyanate groups. The ratio of the number of moles of hydroxyl groups in the polyol (x) to the number of moles of isocyanate groups in the polyisocyanate (y) (NCO / OH ratio) is preferably 0.3 to 0.95, more preferably 0.4 to 0.85. When the hydroxyl group and the isocyanate group are reacted at an appropriate ratio, cohesion and adhesion can be achieved at a high level.

In the present invention, the polyisocyanate (y) contains one or more bifunctional isocyanate compounds (y1).
As the polyisocyanate (y), it is preferable to use only the bifunctional isocyanate compound (y1). As for polyisocyanate (y), polyisocyanate (y) can contain 1 or more types of trifunctional or more than trifunctional isocyanate compounds as needed.
When only a trifunctional or higher functional polyol and only a trifunctional or higher polyisocyanate are used as the raw material polyol of the polyurethane polyol, the molecular structure of the polyurethane polyol becomes rigid and the cohesive force of the adhesive layer becomes higher than the preferred range. There is a fear.
In the pressure-sensitive adhesive of the present invention using a tri- or higher functional polyol as a raw material polyol of the polyurethane polyol, one or more polyisocyanates containing a bifunctional isocyanate compound (y1) as the polyisocyanate (y), preferably a bifunctional isocyanate compound (y1). ) Only, it is possible to obtain an adhesive layer having suitable cohesive force and adhesive force while suppressing excessive crosslinking.

<Catalyst>
Known catalysts can be used as the catalyst, and examples thereof include tertiary amine compounds and organometallic compounds.

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

Examples of organometallic compounds include tin compounds and non-tin compounds.
Examples of the tin compound include dibutyltin dichloride, dibutyltin oxide, dibutyltin dibromide, dibutyltin dimaleate, dibutyltin dilaurate (DBTDL), dibutyltin diacetate, dibutyltin sulfide, tributyltin sulfide, tributyltin oxide, tributyl Examples include tin acetate, triethyltin ethoxide, tributyltin ethoxide, dioctyltin oxide, dioctyltin dilaurate, tributyltin chloride, tributyltin trichloroacetate, and tin 2-ethylhexanoate.
Examples of non-tin compounds include titanium-based compounds such as dibutyltitanium dichloride, tetrabutyltitanate, and butoxytitanium trichloride; lead-based compounds such as lead oleate, lead 2-ethylhexanoate, lead benzoate, and lead naphthenate. Iron systems such as iron 2-ethylhexanoate and iron acetylacetonate; cobalt systems such as cobalt benzoate and cobalt 2-ethylhexanoate; zinc systems such as zinc naphthenate and zinc 2-ethylhexanoate; zirconium naphthenate And the like.

One or more catalysts can be used. When the reactivity of each of the plural kinds of polyols (x) used in combination as required is different, the difference in reactivity may cause gelation or white turbidity of the reaction solution in a single catalyst system. In this case, by using two types of catalysts, it is easy to control the reaction (for example, reaction rate and the like), and the above problem can be solved. A combination of two kinds of catalysts is not particularly limited, and examples thereof include tertiary amine / organometallic, tin / non-tin, and tin / tin. Preferred are tin / tin, more preferably dibutyltin dilaurate and tin 2-ethylhexanoate.
The mass ratio of tin 2-ethylhexanoate and dibutyltin dilaurate (tin 2-ethylhexanoate / dibutyltin dilaurate) is not particularly limited, preferably more than 0 and less than 1, more preferably 0.2 to 0.6. is there. If the mass ratio is less than 1, the catalyst activity is well balanced, gelling and clouding of the reaction solution are effectively suppressed, and the polymerization stability is further improved.

  The usage-amount in particular of 1 or more types of catalyst is not restrict | limited, Preferably it is 0.01-1 mass% with respect to the total amount of polyol (x) and polyisocyanate (y).

<Solvent>
A solvent can be used as needed for the polymerization of the polyurethane polyol (A). A well-known thing can be used as a solvent, Methyl ethyl ketone, ethyl acetate, toluene, xylene, acetone, etc. are mentioned. From the viewpoint of the solubility of the polyurethane polyol (A) and the boiling point of the solvent, ethyl acetate, toluene and the like are particularly preferable.

<Polymerization method>
The polymerization method of the polyurethane polyol (A) is not particularly limited, and known polymerization methods such as a bulk polymerization method and a solution polymerization method can be applied.
The polymerization procedure is not particularly limited,
Procedure 1) Procedure for charging polyol (x), polyisocyanate (y), a catalyst as required, and a solvent as needed into a flask at once;
Procedure 2) A procedure in which polyol (x), a catalyst as necessary, and a solvent as needed are charged into a flask and polyisocyanate (y) is added dropwise thereto.
Procedure 2) is preferred because the reaction is easy to control.

When using a catalyst, the reaction temperature is preferably less than 100 ° C, more preferably 85 to 95 ° C. If reaction temperature is less than 100 degreeC, it is easy to control reaction rate, a crosslinked structure, etc., and it is easy to produce | generate the polyurethane polyol (A) which has a desired molecular weight.
When no catalyst is used, the reaction temperature is preferably 100 ° C. or higher, more preferably 110 ° C. or higher, and the reaction time is preferably 3 hours or longer.

  The weight average molecular weight (Mw) of the polyurethane polyol (A) is preferably 10,000 to 500,000, more preferably 30,000 to 400,000, and particularly preferably 50,000 to 350,000. Good coatability is easily obtained when the Mw of the polyurethane polyol (A) is in an appropriate range.

(Polyfunctional isocyanate compound (B))
As the polyfunctional isocyanate compound (B), known compounds can be used, and compounds exemplified by the polyisocyanate (y) which is a raw material of the polyurethane polyol (A) (specifically, aromatic polyisocyanate, aliphatic polyisocyanate, An aromatic aliphatic polyisocyanate, an alicyclic polyisocyanate, and a trimethylolpropane adduct body / a burette body / trimer) can be used.

  The amount of the polyfunctional isocyanate (B) with respect to 100 parts by mass of the polyurethane polyol (A) is preferably 1 to 50 parts by mass, more preferably 1 to 20 parts by mass, and particularly preferably 5 to 15 parts by mass. If the amount of the polyfunctional isocyanate (B) is 1 part by mass or more, the cohesive force of the adhesive layer is good, and if it is 50 parts by mass or less, the adhesive force of the adhesive layer is good.

(Plasticizer (P))
As described above, the present invention can provide a pressure-sensitive adhesive having good wettability even with a blending composition in which the amount of plasticizer (P) added is small / preferably no plasticizer (P) is added. Therefore, in the pressure-sensitive adhesive of the present invention, the plasticizer (P) is not an essential component in order to improve wettability, but the pressure-sensitive adhesive of the present invention contains one or more plasticizers (P) as necessary. Can do. However, even when the plasticizer (P) is added, the amount can be suppressed to a low level. The amount of the plasticizer (P) with respect to 100 parts by mass of the polyurethane polyol (A) may be, for example, 50 parts by mass or less (0 to 50 parts by mass), preferably 40 parts by mass or less (0 to 40 parts by mass), more preferably. 30 parts by mass or less (0 to 30 parts by mass), more preferably 20 parts by mass or less (0 to 20 parts by mass), particularly preferably 10 parts by mass or less (0 to 10 parts by mass), and most preferably 5 parts by mass or less ( 0-5 parts by mass).

  The plasticizer (P) is not particularly limited, and an organic acid ester having a molecular weight of 250 to 1,000 is preferable from the viewpoint of compatibility with other components.

  Examples of esters of monobasic acid or polybasic acid and alcohol include isostearyl laurate, isopropyl myristate, isocetyl myristate, octyldodecyl myristate, isostearyl palmitate, isocetyl stearate, octyldodecyl oleate, phthalate Dibutyl acid, Dioctyl phthalate, Diheptyl phthalate, Dibenzyl phthalate, Butyl benzyl phthalate, Diisodecyl adipate, Diisostearyl adipate, Dibutyl sebacate, Diisocetyl sebacate, Tributyl acetylcitrate, Tributyl trimellitic acid, Trimerit Examples include trioctyl acid, trihexyl trimellitic acid, trioleyl trimellitic acid, and triisocetyl trimellitic acid.

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

  Examples of esters of monobasic acid or polybasic acid and polyalkylene glycol include, for example, polyethylene glycol dihexylate, polyethylene glycol di-2-ethylhexylate, polyethylene glycol dilaurate, polyethylene glycol dioleate, and dipolyethylene glycol methyl adipate Examples include ether.

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

(solvent)
The pressure-sensitive adhesive of the present invention can contain a solvent, if necessary. A well-known thing can be used as a solvent, Methyl ethyl ketone, ethyl acetate, toluene, xylene, acetone, etc. are mentioned. From the viewpoints of the solubility of the polyurethane polyol (A) and the boiling point of the solvent, ethyl acetate and toluene are particularly preferable.

(Anti-alteration agent (D))
The pressure-sensitive adhesive of the present invention can contain one or more alteration preventing agents (D) as necessary. Thereby, the fall of the various characteristics by long-term use of the adhesion layer can be suppressed. Examples of the alteration inhibitor (D) include hydrolysis resistance, antioxidants, ultraviolet absorbers, and light stabilizers.

<Hydrolysis-resistant agent>
When a hydrolysis reaction occurs in the adhesive layer in a high temperature and high humidity environment and a carboxy group is generated, a hydrolysis-resistant agent can be used to block the carboxy group.
Examples of the hydrolysis-resistant agent include carbodiimide, isocyanate, oxazoline, and epoxy. Among these, a carbodiimide type is preferable from the viewpoint of the hydrolysis inhibiting effect.

A carbodiimide-based hydrolysis inhibitor is a compound having one or more carbodiimide groups in one molecule.
Examples of the monocarbodiimide compound include dicyclohexylcarbodiimide, diisopropylcarbodiimide, dimethylcarbodiimide, diisobutylcarbodiimide, dioctylcarbodiimide, diphenylcarbodiimide, and naphthylcarbodiimide.
The polycarbodiimide compound can be produced by decarboxylation condensation reaction of diisocyanate in the presence of a carbodiimidization catalyst. Here, as the diisocyanate, for example, 4,4′-diphenylmethane diisocyanate, 3,3′-dimethoxy-4,4′-diphenylmethane diisocyanate, 3,3′-dimethyl-4,4′-diphenylmethane diisocyanate, 4,4 '-Diphenyl ether diisocyanate, 3,3'-dimethyl-4,4'-diphenyl ether diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1-methoxyphenyl-2,4-diisocyanate, isophorone diisocyanate, Examples include 4,4′-dicyclohexylmethane diisocyanate and tetramethylxylylene diisocyanate. As the carbodiimidization catalyst, 1-phenyl-2-phospholene-1-oxide, 3-methyl-2-phospholene-1-oxide, 1-ethyl-3-methyl-2-phospholene-1-oxide, 1-ethyl- Examples include 2-phospholene-1-oxide and phospholene oxides such as 3-phospholene isomers.

  Examples of the isocyanate-based hydrolysis inhibitor include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4′-diphenylmethane diisocyanate, and 2,4′-. Diphenylmethane diisocyanate, 2,2′-diphenylmethane diisocyanate, 3,3′-dimethyl-4,4′-biphenylene diisocyanate, 3,3′-dimethoxy-4,4′-biphenylene diisocyanate, 3,3′-dichloro-4, 4'-biphenylene diisocyanate, 1,5-naphthalene diisocyanate, 1,5-tetrahydronaphthalene diisocyanate, tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, dodecamethylene diisocyanate Socyanate, trimethylhexamethylene diisocyanate, 1,3-cyclohexylene diisocyanate, 1,4-cyclohexylene diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, hydrogenated xylylene diisocyanate, lysine diisocyanate, isophorone diisocyanate, 4,4'- Examples include dicyclohexylmethane diisocyanate and 3,3′-dimethyl-4,4′-dicyclohexylmethane diisocyanate.

  Examples of the oxazoline-based hydrolysis inhibitor include 2,2′-o-phenylenebis (2-oxazoline), 2,2′-m-phenylenebis (2-oxazoline), and 2,2′-p-phenylenebis. (2-oxazoline), 2,2'-p-phenylenebis (4-methyl-2-oxazoline), 2,2'-m-phenylenebis (4-methyl-2-oxazoline), 2,2'-p -Phenylenebis (4,4'-dimethyl-2-oxazoline), 2,2'-m-phenylenebis (4,4'-dimethyl-2-oxazoline), 2,2'-ethylenebis (2-oxazoline) 2,2′-tetramethylenebis (2-oxazoline), 2,2′-hexamethylenebis (2-oxazoline), 2,2′-octamethylenebis (2-oxazoline), 2,2′- Chirenbisu (4-methyl-2-oxazoline), and 2,2'-diphenylenebis (2-oxazoline).

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

  The addition amount of the hydrolysis-resistant agent is not particularly limited, and is preferably 0.1 to 5 parts by mass, more preferably 0.2 to 4.5 parts by mass, particularly preferably 100 parts by mass of the polyurethane polyol (A). Is 0.5-3 parts by mass.

<Antioxidant>
Examples of the antioxidant include a radical scavenger and a peroxide decomposer. Examples of the radical scavenger include phenolic compounds and amine compounds. Examples of the peroxide decomposing agent include sulfur compounds and phosphorus compounds.

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

  Examples of phosphorus compounds include triphenyl phosphite, diphenylisodecyl phosphite, 4,4′-butylidene-bis (3-methyl-6-tert-butylphenylditridecyl) phosphite, and cyclic neopentanetetrayl. Bis (octadecylphosphite), tris (nonylphenyl) phosphite, tris (monononylphenyl) phosphite, tris (dinonylphenyl) phosphite, diisodecylpentaerythritol diphosphite, 9,10-dihydro-9-oxa- 10-phosphaphenanthrene-10-oxide, 10- (3,5-di-tert-butyl-4-hydroxybenzyl) -9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10 -Desiloxy- , 10-dihydro-9-oxa-10-phosphaphenanthrene, tris (2,4-di-tert-butylphenyl) phosphite, cyclic neopentanetetraylbis (2,4-di-tert-butylphenyl) Phosphites, cyclic neopentanetetraylbis (2,6-di-tert-butyl-4-methylphenyl) phosphite, and 2,2-methylenebis (4,6-di-tert-butylphenyl) octyl phosphite Etc.

By using an antioxidant, it is possible to prevent thermal degradation of the polyurethane polyol (A) and effectively suppress bleed out of the plasticizer (P) from the adhesive layer.
The addition amount of the antioxidant is not particularly limited, and is preferably 0.01 to 5 parts by mass, more preferably 0.1 to 3 parts by mass, and particularly preferably 0.1 to 0.1 parts by mass with respect to 100 parts by mass of the polyurethane polyol (A). 2 to 2 parts by mass.

  As the antioxidant, from the viewpoint of stability and antioxidant effect, it is preferable to use one or more phenolic compounds that are radical scavengers, and one or more phenolic compounds that are radical scavengers and peroxide decomposers. It is more preferable to use one or more phosphorus compounds in combination. Further, it is particularly preferable to use a phenolic compound that is a radical scavenger and a phosphorus compound that is a peroxide decomposing agent in combination as an antioxidant, and to use these antioxidants in combination with the aforementioned hydrolysis-resistant agent. .

<Ultraviolet absorber>
Examples of the ultraviolet absorber include benzophenone compounds, benzotriazole compounds, salicylic acid compounds, oxalic anilide compounds, cyanoacrylate compounds, and triazine compounds.
The addition amount of the ultraviolet absorber is not particularly limited, and is preferably 0.01 to 3 parts by mass, more preferably 0.1 to 2.5 parts by mass, particularly preferably 100 parts by mass of the polyurethane polyol (A). 0.2 to 2 parts by mass.

<Light stabilizer>
Examples of the light stabilizer include hindered amine compounds and hindered piperidine compounds. The addition amount of the light stabilizer is not particularly limited, and is preferably 0.01 to 2 parts by mass, more preferably 0.1 to 1.5 parts by mass, particularly preferably 100 parts by mass of the polyurethane polyol (A). 0.2 to 1 part by mass.

(Antistatic agent (E))
The pressure-sensitive adhesive of the present invention can contain one or more antistatic agents (E) as required.
Examples of the antistatic agent include inorganic salts, polyhydric alcohol compounds, ionic liquids, surfactants, and the like, and among these, ionic liquids are preferable. The “ionic liquid” is also called a room temperature molten salt, and is a salt that has fluidity at 25 ° C.

  Examples of inorganic salts include 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.

  Examples of the polyhydric alcohol compound include propanediol, butanediol, hexanediol, polyethylene glycol, trimethylolpropane, and pentaerythritol.

  Examples of ionic liquids containing imidazolium ions include 1-ethyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide, 1,3-dimethylimidazolium bis (trifluoromethylsulfonyl) imide, and 1-butyl. Examples include -3-methylimidazolium bis (trifluoromethylsulfonyl) imide.

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

  Examples of ionic liquids containing ammonium ions include 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 bistrifluoromethanesulfone An imide etc. are mentioned.

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

  Surfactants are classified into low molecular surfactants and high molecular surfactants. In any type, there are nonionic, anionic, cationic and amphoteric types.

Nonionic low molecular surfactants include glycerin fatty acid esters, polyoxyalkylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene alkylamines, polyoxyethylene alkylamine fatty acid esters, and fatty acid diethanolamides. It is done.
Examples of the anionic low molecular surfactant include alkyl sulfonates, alkyl benzene sulfonates, and alkyl phosphates.
Examples of the cationic low molecular surfactant include tetraalkylammonium salts and trialkylbenzylammonium salts.
Examples of amphoteric low molecular surfactants include alkyl betaines and alkyl imidazolium betaines.

Examples of nonionic polymer surfactants include polyether ester amide type, ethylene oxide-epichlorohydrin type, and polyether ester type.
Examples of the anionic polymer surfactant include polystyrene sulfonic acid type.
Examples of the cationic polymer surfactant include a quaternary ammonium base-containing acrylate polymer type.
Examples of amphoteric polymer surfactants include amino acid-type amphoteric surfactants such as higher alkylaminopropionates, betaine-type amphoteric surfactants such as higher alkyldimethylbetaine, and higher alkyldihydroxyethylbetaine.

  The addition amount of the antistatic agent (E) is preferably 0.01 to 10 parts by mass, more preferably 0.03 to 5 parts by mass with respect to 100 parts by mass of the polyurethane polyol (A).

(Leveling agent)
The pressure-sensitive adhesive of the present invention can contain a leveling agent as required. By adding a leveling agent, the leveling property of the adhesive layer can be improved. Examples of the leveling agent include an acrylic leveling agent, a fluorine leveling agent, a silicone leveling agent, and the like. From the viewpoint of suppressing adherend contamination after re-peeling the adhesive sheet, an acrylic leveling agent is preferable.

  The weight average molecular weight (Mw) of the leveling agent is not particularly limited, and is preferably 500 to 20,000, more preferably 1,000 to 15,000, and particularly preferably 2,000 to 10,000. When Mw is 500 or more, the amount of vaporization from the coating layer is sufficiently small when the coating layer is heated and dried, and surrounding contamination is suppressed. If Mw is 20,000 or less, the improvement effect of the leveling property of an adhesion layer will express effectively.

  The addition amount of the leveling agent is not particularly limited, and is preferably 0.001 with respect to 100 parts by mass of the polyurethane polyol (A) from the viewpoint of suppressing contamination of the adherend after re-peeling the adhesive sheet and improving the leveling property of the adhesive layer. To 2 parts by mass, more preferably 0.01 to 1.5 parts by mass, and particularly preferably 0.1 to 1 part by mass.

(Other optional ingredients)
The pressure-sensitive adhesive of the present invention can contain other optional components as necessary, as long as the effects of the present invention are not impaired. Other optional components include catalysts, resins other than urethane resins, fillers (talc, calcium carbonate, titanium oxide, etc.), metal powders, colorants (pigments, etc.), foils, softeners, electrical conductivity Agents, silane coupling agents, lubricants, corrosion inhibitors, heat resistance stabilizers, weather resistance stabilizers, polymerization inhibitors, antifoaming agents, and the like.

"Adhesive sheet"
The pressure-sensitive adhesive sheet of the present invention includes a base sheet and a pressure-sensitive adhesive layer made of a cured product of the pressure-sensitive adhesive of the present invention. An adhesion layer can be formed in the single side | surface or both surfaces of a base material sheet. If necessary, the exposed surface of the adhesive layer can be covered with a release sheet. The release sheet is peeled off when the pressure-sensitive adhesive sheet is attached to the adherend.

In FIG. 1, the schematic cross section of the adhesive sheet of 1st Embodiment which concerns on this invention is shown. In FIG. 1, reference numeral 10 is an adhesive sheet, reference numeral 11 is a base sheet, reference numeral 12 is an adhesive layer, and reference numeral 13 is a release sheet. The pressure-sensitive adhesive sheet 10 is a single-sided pressure-sensitive adhesive sheet in which a pressure-sensitive adhesive layer is formed on one side of a base sheet.
In FIG. 2, the schematic cross section of the adhesive sheet of 2nd Embodiment which concerns on this invention is shown. In FIG. 2, reference numeral 20 is an adhesive sheet, reference numeral 21 is a base material sheet, reference numerals 22A and 22B are adhesive layers, and reference numerals 23A and 23B are release sheets. The pressure-sensitive adhesive sheet 20 is a double-sided pressure-sensitive adhesive sheet in which pressure-sensitive adhesive layers are formed on both surfaces of a base sheet.

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

The constituent resin of the resin sheet is not particularly limited. For example, ester resins such as polyethylene terephthalate (PET); olefin resins such as polyethylene (PE) and polypropylene (PP); vinyl resins such as polyvinyl chloride; nylon 66 Amide resins such as urethane resins (including foams), combinations thereof, and the like.
The thickness of the resin sheet excluding the polyurethane sheet is not particularly limited, and is preferably 15 to 300 μm. The thickness of the polyurethane sheet (including foam) is not particularly limited, and is preferably 20 to 50,000 μm.
The paper is not particularly limited, and examples thereof include plain paper, coated paper, and art paper.
The constituent metal of the metal foil is not particularly limited, and examples thereof include aluminum, copper, and combinations thereof.
As described above, since the pressure-sensitive adhesive of the present invention has excellent substrate adhesion, the pressure-sensitive adhesive sheet of the present invention is preferable because it has a high degree of freedom in selecting a substrate sheet to be used.

  The release sheet is not particularly limited, and a known release sheet in which a known release treatment such as application of a release agent is performed on the surface of a resin sheet or paper can be used.

An adhesive sheet can be manufactured by a well-known method.
First, the pressure-sensitive adhesive of the present invention is applied to the surface of the base sheet to form a coating layer made of the pressure-sensitive adhesive of the present invention. A known method can be applied as the coating method, and examples thereof include 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.
Next, the coating layer is dried and cured to form an adhesive layer made of a cured product of the adhesive of the present invention. The heat drying temperature is not particularly limited, and is preferably about 60 to 150 ° C.
The thickness of the pressure-sensitive adhesive layer can be appropriately designed depending on the use of the pressure-sensitive adhesive sheet, and is, for example, about 5 to 300 μm. In the present specification, “thickness of the adhesive layer” is a thickness after drying unless otherwise specified.
Next, if necessary, a release sheet is attached to the exposed surface of the adhesive layer by a known method.
A single-sided adhesive sheet can be manufactured as described above.
A double-sided PSA sheet can be produced by performing the above operations on both sides.

  Contrary to the above method, the pressure-sensitive adhesive of the present invention is applied to the surface of the release sheet to form a coating layer made of the pressure-sensitive adhesive of the present invention, and then the coating layer is dried and cured to produce the pressure-sensitive adhesive of the present invention. An adhesive layer made of a cured product of the agent may be formed, and finally a substrate sheet may be laminated on the exposed surface of the adhesive layer.

As described above, according to the present invention, an adhesive layer having good wettability, good bendability, good removability, and less adherend contamination after re-peeling. An adhesive that can be formed can be provided.
According to the present invention, the addition amount of the plasticizer is small / preferably the composition having no addition amount of the plasticizer has good wettability, good curvability, and good removability. It is possible to provide an adhesive capable of forming an adhesive layer with little adherend contamination after re-peeling.

  Hereinafter, synthesis examples, examples according to the present invention, and comparative examples will be described. In the following description, “part” means “part by mass” and “%” means “mass%” unless otherwise specified.

[Measurement of molecular weight]
The weight average molecular weight (Mw) and the number average molecular weight (Mn) were measured by gel permeation chromatography (GPC) method. The measurement conditions are as follows. Mw and Mn are both polystyrene equivalent values.
Apparatus: SHIMADZU Prominence (manufactured by Shimadzu Corporation),
Column: Three SHODEX LF-804 (Showa Denko Co., Ltd.) connected in series,
Detector: differential refractive index detector,
Solvent: tetrahydrofuran (THF),
Flow rate: 0.5 mL / min,
Solvent temperature: 40 ° C.
Sample concentration: 0.02%
Sample injection volume: 200 μL.

[material]
The materials used are as follows.
<Bifunctional polyol (x1)>
(X1-1): Sannix PP-400 (polyether polyol, number average molecular weight Mn400, hydroxyl number 2, EO not contained, manufactured by Sanyo Chemical Industries, Ltd.),
(X1-2): Sannix PP-1000 (polyether polyol, number average molecular weight Mn1000, hydroxyl number 2, EO-free, manufactured by Sanyo Chemical Industries, Ltd.)
(X1-3): Kuraray polyol P-1010 (polyester polyol, number average molecular weight Mn1000, hydroxyl number 2, EO-free, manufactured by Kuraray Co., Ltd.)
(X1-4): Kuraray polyol P-4010 (polyester polyol, number average molecular weight Mn4000, hydroxyl number 2, EO-free, manufactured by Kuraray Co., Ltd.),
(X1-5): PEG-400 (polyether polyol, number average molecular weight Mn400, hydroxyl number 2, EO-containing, manufactured by Toho Chemical Industry Co., Ltd.)
(X1-6): PEG-1000 (polyether polyol, number average molecular weight Mn1000, hydroxyl number 2, EO-containing, manufactured by Toho Chemical Industry Co., Ltd.)
(X1-7): Preminol 5001F (polyether polyol, number average molecular weight Mn4000, hydroxyl number 2, EO content, manufactured by Asahi Glass Co., Ltd.).

<Trifunctional or higher polyol (x2)>
(X2-1): Preminol 7012 (polyether polyol, number average molecular weight Mn10000, hydroxyl number 3, EO containing, manufactured by Asahi Glass Co., Ltd.),
(X2-2): Exenol 851 (polyether polyol, number average molecular weight Mn6700, hydroxyl number 3, EO containing, manufactured by Asahi Glass Co., Ltd.)
(X2-3): Exenol 828 (polyether polyol, number average molecular weight Mn5000, hydroxyl number 3, EO containing, manufactured by Asahi Glass Co., Ltd.)
(X2-4): Adeka polyether AM-302 (polyether polyol, number average molecular weight Mn3000, hydroxyl number 3, containing EO, manufactured by ADEKA),
(X2-5): Exenol 5030 (polyether polyol, number average molecular weight Mn5100, hydroxyl number 3, EO not contained, manufactured by Asahi Glass Co., Ltd.),
(X2-6): DK polyol G480 (polyether polyol, number average molecular weight Mn350, hydroxyl number 3, EO-free, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.).

<Polyisocyanate (y)>
(Y-1): Death module H (hexamethylene diisocyanate, manufactured by Sumika Covestro),
(Y-2): Takenate 500 (xylylene diisocyanate, manufactured by Mitsui Chemicals),
(Y-3): Sumidur HT (trimethylolpropane adduct of hexamethylene diisocyanate, non-volatile content 75%, manufactured by Sumika Covestro).

<Polyfunctional isocyanate compound (B)>
(B-1): Sumidur HT (trimethylolpropane adduct of hexamethylene diisocyanate, non-volatile content 75%, manufactured by Sumika Covestro)
(B-2): Takenate D-110N (trimethylolpropane adduct of xylylene diisocyanate, non-volatile content 75%, manufactured by Mitsui Chemicals)
(B-3): Coronate HX (Nulate body of hexamethylene diisocyanate, non-volatile content 100%, manufactured by Tosoh Corporation).

<Anti-alteration agent (D)>
(D-1): IRGANOX 1010 (manufactured by BASF), hindered phenol antioxidant.

<Plasticizer (P)>
(P-1): Monosizer W262 (manufactured by DIC), polyetherester compound,
(P-2): Unistar M-183 (manufactured by NOF Corporation), methyl oleate.

<Antistatic agent (E)>
(E-1): Ionic liquid, tri-n-butylmethylammonium bistrifluoromethanesulfonimide.

(Synthesis Example 1)
In a four-necked flask equipped with a stirrer, reflux condenser, nitrogen inlet tube, thermometer, and dropping funnel, 2 parts of bifunctional polyol (x1-1), 98 parts of trifunctional polyol (x2-1), and bifunctional 1.0 part of polyisocyanate (y-1) (amount in which NCO / OH is 0.5) was charged. To this, 100 parts of toluene, 0.03 part of dibutyltin dilaurate and 0.01 part of 2-ethylhexanoate as catalysts were added, and the temperature was gradually raised to 90 ° C., followed by reaction at 90 ° C. for 2 hours. Sampling was performed at any time, and the disappearance of the remaining isocyanate group was confirmed by infrared absorption (IR) spectrum, and then the reaction solution was cooled to complete the reaction. As described above, a solution (nonvolatile content: 50%) of the polyurethane polyol (A-1) was obtained. Mw of the obtained polyurethane polyol (A-1) was 75,000. Table 1-1 shows the blending composition and Mw of the obtained polyurethane polyol (A-1). In Table 1-1 to Table 1-4 and Table 2-1 to Table 2-4, the unit of the blending amount is [part].
In addition, the calculation method of the part amount of bifunctional polyisocyanate (y-1) is as follows.
(Part of (y-1)) [part] =
(NCO / OH ratio) × (molecular weight of (y−1)) / (number of NCO groups of (y−1)) ×
[(Partial amount of (x1-1)) / (Molecular weight of (x1-1)) × (Number of hydroxyl groups of (x1-1))
+ (Part of (x2-1)) / (molecular weight of (x2-1)) × (number of hydroxyl groups of (x2-1))]]
= 0.5 × 168/2 × (2/400 × 2 + 98/10000 × 3)
≒ 1.7 parts

(Synthesis Examples 2 to 21, Synthesis Examples 31 and 32)
In each of Synthesis Examples 2 to 21 and Synthesis Examples 31 and 32, a polyurethane polyol (A-2) was prepared in the same manner as in Synthesis Example 1 except that the blending compositions shown in Table 1-1 to Table 1-4 were changed. A solution of (A-21), (H-1), and (H-2) was obtained. In each synthesis example, Mw of the obtained polyurethane polyol is shown in Table 1-1 to Table 1-4.

Example 1
100 parts of the solution of the polyurethane polyol (A-1) obtained in Synthesis Example 1, 10 parts of the polyfunctional isocyanate compound (B-1), 1.0 part of the antioxidant (D-1), and acetic acid as a solvent A urethane-based pressure-sensitive adhesive was obtained by blending 100 parts of ethyl and stirring with a disper. In addition, the usage-amount of each material other than a solvent shows a non-volatile content conversion value. The composition is shown in Table 2-1.
A 50 μm thick polyethylene terephthalate film (PET film, Lumirror T-60: manufactured by Toray Industries, Inc.) was prepared as a base sheet. The pressure-sensitive adhesive obtained was coated on one side of the base sheet so that the thickness of the pressure-sensitive adhesive layer after drying was 12 μm, and dried at 100 ° C. for 2 minutes to form a pressure-sensitive adhesive layer. On this adhesive layer, a 38 μm-thick release sheet (Super Stick SP-PET38: manufactured by Lintec Corporation) was attached to obtain an adhesive sheet. After curing at 23 ° C.-50% RH for 1 week, it was subjected to various evaluations.

(Examples 2-23, Comparative Examples 1-2)
In each of Examples 2 to 23 and Comparative Examples 1 and 2, the pressure-sensitive adhesive and the adhesive were the same as in Example 1 except that the formulation was changed as shown in Tables 2-1 to 2-4. An adhesive sheet was obtained.

(Comparative Example 3)
100 parts of trifunctional polyol (x2-2), 12.6 parts of polyfunctional isocyanate compound (B-3), 0.04 part of dibutyltin dilaurate as a catalyst, 210 parts of ethyl acetate as a solvent, By stirring, a urethane-based pressure-sensitive adhesive was obtained. In addition, the usage-amount of each material other than a solvent shows a non-volatile content conversion value. The composition is shown in Table 2-3.
A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that the obtained urethane-based pressure-sensitive adhesive was used and the pressure-sensitive adhesive layer was dried at 130 ° C. for 2 minutes.

[Evaluation items and methods]
Evaluation items and evaluation methods are as follows.
(Removability)
The obtained pressure-sensitive adhesive sheet was prepared in a size of 25 mm in width and 100 mm in length, and used as a measurement sample. Next, the release sheet was peeled from the measurement sample in an atmosphere of 23 ° C.-50% RH, the exposed adhesive layer was attached to a caustic soda glass plate, and pressure-bonded using a 2 kg roll. Then, it was left for 24 hours under 60 ° C.-90% RH condition. Air-cooled in an atmosphere of 23 ° C.-50% RH for 30 minutes, and then adhered in accordance with JISZ0237 using a tensile tester (Tensilon: manufactured by Orientec Co., Ltd.) at a peeling speed of 300 mm / min and a peeling angle of 180 ° The force was measured. In addition, the one where adhesive strength is low is easy to peel again. The evaluation criteria are as follows.
A: Less than 10 mN / 25 mm, excellent.
○: 10 mN / 25 mm or more and less than 20 mN / 25 mm, good.
Δ: 20 mN / 25 mm to 50 mN / 25 mm, practical use is possible.
X: Over 50 mN / 25 mm, impractical.

(Wettability)
The obtained adhesive tape was prepared to have a width of 50 mm and a length of 100 mm, 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 part of the exposed adhesive layer was brought into contact with the glass plate while holding both ends of the adhesive tape with both hands, and then both hands were released. The wettability of the pressure-sensitive adhesive was evaluated by measuring the time until the entire pressure-sensitive adhesive layer adhered to the glass plate by its own weight. Since the wettability (affinity) with respect to glass is so favorable that time until it adhere | attaches with a glass plate, glass can be favorably protected in the manufacturing process using glass. The evaluation criteria are as follows.
A: Less than 2 seconds until adhesion, excellent.
○: 2 seconds or more and less than 3 seconds until adhesion, good.
Δ: 3 seconds or more and less than 5 seconds until adhesion, practical use possible.
X: 5 seconds or more until contact, impractical.

(Curvature)
The obtained adhesive tape was prepared to have a width of 10 mm and a length of 100 mm, and used as a measurement sample. Next, the release sheet was peeled from the measurement sample in an atmosphere of 23 ° C.-50% RH. Next, an adhesive tape sample having a length and a width of 10 mm corresponding to a half circumference of the circumference was attached along the circumferential surface of a glass cylinder (diameter: 15 mm). After being left for 72 hours at 60 ° C.-90% RH, the floating state of the measurement sample was observed. When floating was observed at the end, the length of the floating portion was measured. The evaluation criteria are as follows.
(Double-circle): There is no float in an edge part, and the whole measurement sample adheres and is excellent.
○: Slightly lifted at the end, lifted by 0.3 mm or less, good.
Δ: Slight float at the end, float above 0.3 mm and below 1 mm, practical use possible.
X: Floating at the end, floating above 1 mm, impractical.

(Base material adhesion)
After the peelable sheet was peeled from the obtained pressure-sensitive adhesive sheet, the exposed pressure-sensitive adhesive layer was rubbed with a finger so as to reciprocate, and it was evaluated whether or not the pressure-sensitive adhesive layer dropped from the base material sheet. The evaluation criteria are as follows.
(Double-circle): It is excellent that an adhesive does not fall off from a base material sheet even if it goes 30 times or more.
○: Adhesive drops off from the base sheet in 21 to 30 reciprocations.
Δ: Practical use is possible in which the adhesive drops off from the base sheet in 11 to 20 reciprocations.
X: The pressure-sensitive adhesive falls off from the substrate sheet within 10 reciprocations, impractical.

(Adherent contamination)
The obtained pressure-sensitive adhesive sheet was prepared in a size of 70 mm in width and 100 mm in length, and used as a measurement sample. Next, the release sheet was peeled from the measurement sample in an atmosphere of 23 ° C.-50% RH, the exposed adhesive layer was attached to a caustic soda glass plate, and pressure-bonded using a laminator. Then, it was left for 72 hours under 60 ° C.-90% RH condition. After air cooling in an atmosphere of 23 ° C.-50% RH for 1 hour, the measurement sample is peeled off from the glass plate, and the portion where the measurement sample is attached to the glass surface is irradiated with LED lamp light in a dark room. The contamination status was visually evaluated. The evaluation criteria are as follows.
A: Excellent, no contamination is observed on the glass surface.
Good: Slightly foreign matter or clouding is observed at one place on the glass surface.
(Triangle | delta): The foreign material or cloudiness is slightly recognized by 2-3 places of the glass surface, and it is practical use.
X: Foreign matter or cloudiness is slightly observed at 4 or more locations on the glass surface, or dark foreign matter or cloudiness clearly recognized at 3 locations or less is observed, impractical.

[Evaluation results]
The evaluation results are shown in Tables 2-1 to 2-4.

In Examples 1-23,
A polyurethane polyol (A) which is a reaction product of a polyol (x) containing a trifunctional or higher polyol (x2) and a polyisocyanate (y);
A polyfunctional isocyanate compound (B),
Trifunctional or higher polyols (x2) has an EO group, Mn comprises trifunctional or more polyether polyols (x2 _H) 3,000 greater,
A pressure-sensitive adhesive in which polyisocyanate (y) contains a bifunctional isocyanate compound was produced.

  Each of the pressure-sensitive adhesive sheets obtained in Examples 1 to 23 has re-peelability after storage under conditions of 60 ° C.-90% RH, wettability to glass, and after storage under conditions of 60 ° C.-90% RH. The evaluation results of the bendability, substrate adhesion, and adherend contamination after storage at 60 ° C.-90% RH were good.

  In Comparative Example 1, a pressure-sensitive adhesive was prepared using a comparative polyurethane polyol which is a reaction product of a bifunctional polyol, a trifunctional polyol having an EO group and a Mn of 3,000 or less, and a bifunctional polyisocyanate. Manufactured. The pressure-sensitive adhesive sheet obtained in Comparative Example 1 has an evaluation result of the flexibility after being stored under the condition of 60 ° C.-90% RH and the adherend contamination property after being stored under the condition of 60 ° C.-90% RH. It was bad.

  In Comparative Example 2, a pressure-sensitive adhesive using a bifunctional polyol, a polyurethane polyol for comparison which is a reaction product of a bifunctional polyisocyanate and a trifunctional polyol having no EO group and having an Mn of more than 3,000 Manufactured. The pressure-sensitive adhesive sheet obtained in Comparative Example 2 had poor wettability evaluation results for glass.

In Comparative Example 3, a pressure-sensitive adhesive was produced by a one-shot method using a trifunctional polyol having an EO group and Mn exceeding 3,000 and a polyfunctional isocyanate compound without using a polyurethane polyol. The pressure-sensitive adhesive sheet obtained in Comparative Example 3 had poor evaluation results for the curvability after being stored at 60 ° C.-90% RH and the substrate adhesion.

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

10, 20 Adhesive sheet 11, 21 Base sheet 12, 22A, 22B Adhesive layer 13, 23A, 23B Release sheet

Claims (8)

A polyurethane polyol (A) which is a reaction product of a polyol (x) containing a trifunctional or higher polyol (x2) and a polyisocyanate (y);
A pressure-sensitive adhesive containing a polyfunctional isocyanate compound (B),
Trifunctional or higher polyols (x2) is 1 has one or more ethyleneoxy groups in the molecule, includes a number average molecular weight of 3,000 greater than trifunctional or more polyether polyols (x2 _H),
The adhesive whose polyisocyanate (y) contains a bifunctional isocyanate compound (y1).   The pressure-sensitive adhesive according to claim 1, wherein the polyol (x) further contains a bifunctional polyol (x1).   The pressure-sensitive adhesive according to claim 2, wherein the bifunctional polyol (x1) is one or more polyols selected from the group consisting of a bifunctional polyether polyol and a bifunctional polyester polyol.   The pressure-sensitive adhesive according to claim 3, wherein the bifunctional polyol (x1) comprises a bifunctional polyether polyol having one or more ethyleneoxy groups in one molecule.   The pressure-sensitive adhesive according to any one of claims 2 to 4, wherein the bifunctional polyol (x1) has a number average molecular weight of 200 to 6,000.   Furthermore, the adhesion of any one of Claims 1-5 containing 1 or more types of alteration inhibitors chosen from the group which consists of antioxidant, a hydrolysis-resistant agent, a ultraviolet absorber, and a light stabilizer. Agent.   The pressure-sensitive adhesive according to any one of claims 1 to 6, further comprising an antistatic agent.   The adhesive sheet containing a base material sheet and the adhesion layer which consists of a hardened | cured material of the adhesive in any one of Claims 1-7.

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