WO2020230648A1

WO2020230648A1 - Solution containing hydroxyl-terminated urethane prepolymer, production method for solution containing hydroxyl-terminated urethane prepolymer, adhesive, adhesive sheet, and production method for adhesive sheet

Info

Publication number: WO2020230648A1
Application number: PCT/JP2020/018276
Authority: WO
Inventors: 秀平齋藤; 嘉孝戸根
Original assignee: 東洋インキＳｃホールディングス株式会社; トーヨーケム株式会社
Priority date: 2019-05-15
Filing date: 2020-04-30
Publication date: 2020-11-19
Also published as: JP6705530B1; TW202106744A; JP2020186320A; KR20210143867A; CN113710378A

Abstract

Provided is a solution that contains a hydroxyl-terminated urethane prepolymer. The solution is for use in an adhesive, uses a reduced amount of an organic solvent, has a relatively high solid component concentration, and has a relatively low viscosity. Also provided is an adhesive that uses a reduced amount of an organic solvent, has a relatively high solid component concentration, and has a relatively low viscosity when applied and therefore has favorable application suitability. This solution that contains a hydroxyl-terminated urethane prepolymer is for an adhesive and includes a hydroxyl-terminated urethane prepolymer (UPH) that is the product of a reaction between: at least one type of active-hydroxyl-group-containing compound (HX) that has a plurality of active hydroxyl groups per molecule thereof; and at least one type of polyisocyanate (N). The solid component concentration of the solution is at least 80 mass%, and the viscosity of the solution at 25° after standing for one hour at 25°C immediately after being prepared is no greater than 8000 mPa·s. This adhesive includes: the solution that contains a hydroxyl-terminated urethane prepolymer; and a polyfunctional isocyanate compound (I).

Description

Hydroxyl-terminated urethane prepolymer-containing solution and its manufacturing method, adhesive, and pressure-sensitive adhesive sheet and its manufacturing method

The present invention relates to a hydroxyl-terminated urethane prepolymer-containing solution for a pressure-sensitive adhesive and a method for producing the same, a pressure-sensitive adhesive, and a pressure-sensitive adhesive sheet and a method for manufacturing the same.

Conventionally, as a surface protective sheet for various members, an adhesive sheet in which an adhesive layer is formed on a base material sheet has been widely used. Examples of the pressure-sensitive adhesive include an acrylic pressure-sensitive adhesive, a silicone-based pressure-sensitive adhesive, and a urethane-based pressure-sensitive adhesive. Acrylic adhesives have excellent adhesive strength, but because of their strong adhesive strength, they do not have good removability after being attached to an adherend. In particular, after a lapse of time in a high-temperature and high-humidity environment, the re-peelability is further reduced due to the increase in adhesive strength, and the adhesive tends to remain on the surface of the adherend after re-peeling. .. Silicone adhesives tend to contaminate the adherend, and silicone resins with relatively low molecular weight may volatilize and adsorb to the surface of devices such as electronic devices, causing problems. On the other hand, the urethane-based adhesive has good adhesion to the adherend, has relatively excellent removability, and is difficult to volatilize.
In the present specification, the "adhesive" is a removable adhesive (removable adhesive), and the "adhesive sheet" is a removable adhesive sheet (removable adhesive sheet).

Flat panel displays such as liquid crystal displays (LCDs) and organic electroluminescence displays (OELDs), as well as touch panel displays that combine such flat panel displays and touch panels, include televisions (TVs), personal computers (PCs), mobile phones, and Widely used in electronic devices such as mobile information terminals.
Urethane-based adhesive sheets include flat panel displays and touch panel displays, as well as substrates manufactured or used in these manufacturing processes (glass substrates, and ITO / glass substrates on which an ITO (indium tin oxide) film is formed on the glass substrates. Etc.) and is suitably used as a surface protection sheet for optical members and the like.

As a method for producing a urethane-based pressure-sensitive adhesive, a method using a hydroxyl group-terminated urethane prepolymer which is a reaction product of an active hydrogen group-containing compound such as a polyol and a polyisocyanate and a polyfunctional isocyanate compound, and a hydroxyl group-terminated urethane prepolymer are used. There is a method (one-shot method) in which the polyol and the polyfunctional isocyanate compound are reacted at once without any reaction.

A general method for producing an adhesive sheet is a coating step of applying an adhesive on a base sheet and a heat-drying treatment of the formed coating layer to form an adhesive layer containing a cured product of the adhesive. It includes a heating step, a winding step of winding the obtained adhesive sheet around a winding core to form an adhesive sheet roll, and a curing step of curing the adhesive sheet roll.

Japanese Patent No. 5194801 Japanese Patent No. 6270818 Japanese Patent No. 5466366 Japanese Patent No. 60070633

Urethane-based adhesives cure immediately after production, but if the initial curability is too high, the pot life will be shortened, and the viscosity of the adhesive will become too high before the adhesive is applied on the base sheet. There is a risk that uniform coating will not be possible. If the initial curability of the urethane-based adhesive is too low, the coating layer or the adhesive layer receives hot air during heating and drying of the coating layer, or mechanically when winding and curing the adhesive sheet obtained after heating and drying. Under the influence of stress, the adhesive layer may have poor surface appearance such as winding core step marks, citron skin, and curl. The urethane-based pressure-sensitive adhesive preferably has good initial curability while having a good pot life.

Conventionally, urethane-based pressure-sensitive adhesives generally contain an organic solvent, which adjusts the viscosity to a relatively low viscosity suitable for coating. However, the use of volatile organic compounds (VOCs) is not preferable from the viewpoint of the environment, and it is preferable that the amount used is small. In the conventional urethane-based pressure-sensitive adhesive, when the amount of the organic solvent used is reduced, the viscosity of the pressure-sensitive adhesive tends to increase and the coatability tends to decrease.
It is preferable that a urethane-based pressure-sensitive adhesive having a relatively low viscosity suitable for coating can be provided even if the amount of the organic solvent used is reduced and the solid content concentration is increased. Conventionally, the solid content concentration of the urethane-based pressure-sensitive adhesive is generally less than 70% by mass, but from the viewpoint of reducing VOC, it is preferably 70% by mass or more, more preferably 80% by mass or more.

Patent documents 1 to 4 can be mentioned as related documents of the present invention.
In Patent Document 1,
A polyol and a polyisocyanate compound are reacted at an excess ratio of isocyanate groups to obtain an isocyanate group-terminated prepolymer, and then a chain extender is reacted with the isocyanate group-terminated prepolymer, and a terminal terminator is further reacted if necessary. It is a manufacturing method of urethane resin to be made.
The chain extender contains a polyfunctional compound (X) having three or more functional groups capable of reacting with an isocyanate group, two of the functional groups of the polyfunctional compound (X) are primary hydroxyl groups, and the rest. The functional group is a secondary hydroxyl group or a tertiary hydroxyl group,
A method for producing a urethane resin for a pressure-sensitive adhesive, wherein the polyfunctional compound (X) is at least one selected from the group consisting of a compound represented by the chemical formula (1) and a compound represented by the chemical formula (2) is disclosed. (Claim 1).
Patent Document 1 discloses a pressure-sensitive adhesive containing a urethane resin obtained by the above production method (claim 5).

Patent Document 1 discloses a method for producing a hydroxyl-terminated urethane prepolymer-containing solution by two-step polymerization and a urethane-based pressure-sensitive adhesive containing the hydroxyl-terminated urethane prepolymer-containing solution.
Patent Document 1 describes that "the pressure-sensitive adhesive of the present invention does not have to lower the solid content concentration in order to lower the viscosity because the urethane resin is not gelled" (paragraph 0055). However, the polyurethane solutions obtained in Examples 1 to 8 have a low solid content concentration of 47 to 50% by mass (Table 1) and a low viscosity at 24 ° C. of 3700 to 5100 mPa · s (Table 1). It is presumed that the pressure-sensitive adhesive using the polyurethane solution has a low solid content concentration, and the VOC reduction effect cannot be said to be sufficient. That is, Patent Document 1 does not specifically describe a solution containing a hydroxyl-terminated urethane prepolymer having a high solid content concentration and a pressure-sensitive adhesive having a high solid content concentration containing the solution.

In Patent Document 2,
(A) an active hydrogen compound having an average molecular weight 1.2 × 10 ⁴ or more and an average functionality 3,
(B) an active hydrogen compound having an average molecular weight 0.1 × 10 ⁴ or more and an average functionality 2,
(C) A solvent-free polyurethane-based pressure-sensitive adhesive obtained by reacting with an organic polyisocyanate having an average functional group number of 2 is disclosed (claim 1).
Patent Document 2 states that "the polyurethane adhesive of the present invention obtained by combining the active hydrogen compound (A) and the active hydrogen compound (B) has an appropriate cohesive force and becomes a polymer having a flexible structure. In the polyurethane-based pressure-sensitive adhesive thus obtained, the mixture has an appropriate viscosity at the time of coating, which is also advantageous in terms of coatability. ”(Paragraph 0019).
However, the urethane-based pressure-sensitive adhesive described in Patent Document 2 is a urethane-based pressure-sensitive adhesive produced by the one-shot method. In general, the pressure-sensitive adhesive layer using the urethane-based pressure-sensitive adhesive obtained by the one-shot method is hard, and the surface smoothness of the pressure-sensitive adhesive layer tends to deteriorate due to curing shrinkage. In particular, the urethane-based pressure-sensitive adhesive described in Patent Document 2 does not contain a diluent such as a solvent and a plasticizer, and therefore cannot be said to have good coatability, and the above tendency is remarkable. The viscosity of the urethane-based adhesive described in Patent Document 2 is unknown.

Patent Document 3 includes (A) a terminal isocyanate group-containing urethane prepolymer obtained by reacting a polyol with an excess amount of a polyisocyanate compound, (B) a fine powder coating amine, and (C) a tackifier. A one-component solvent-free urethane-based pressure-sensitive adhesive composition is disclosed (claim 1).
Patent Document 3 states that "a solvent-free pressure-sensitive adhesive composition containing substantially no solvent. Therefore, when a pressure-sensitive adhesive is produced from the pressure-sensitive adhesive composition of the present invention, an odor or a volatile organic compound ( It is possible to prevent environmental pollution caused by VOC) and the like. ”(Paragraph 0025). However, the urethane-based pressure-sensitive adhesive described in Patent Document 3 does not contain a diluent such as a solvent and a plasticizer, and therefore has poor coatability. The viscosity of the urethane-based adhesive described in Patent Document 3 is unknown.

Patent Document 4 describes 100 parts by weight of a polyurethane resin (A) having a primary hydroxyl group at the terminal and a hydroxyl value of 10 to 40 mgKOH / g, 1 to 20 parts by weight of a polyfunctional isocyanate compound (B), and poly. A removable urethane pressure-sensitive adhesive composition containing 25 to 100 parts by weight of at least one (C) selected from an alkylene glycol-based compound, an epoxy-based compound, and a phosphoric acid ester-based compound is disclosed (claim 1).
In Synthesis Examples 1 to 5 and Examples 1 to 18 of Patent Document 4, a polyurethane resin solution having a non-volatile content of 60% by mass and a urethane-based pressure-sensitive adhesive containing the same are produced.
The solid content concentration of the polyurethane resin solutions obtained in Synthesis Examples 1 to 5 is at a conventional general level, and the urethane-based pressure-sensitive adhesives according to Examples 1 to 18 containing this have a conventional general solid content concentration. It is presumed to be a level, the VOC reduction effect is not sufficient, and the viscosity is unknown.

The present invention has been made in view of the above circumstances, and is a hydroxyl-terminated urethane prepolymer-containing solution for a pressure-sensitive adhesive having a reduced amount of organic solvent used, a relatively high solid content concentration, and a relatively low viscosity. The purpose is to provide.
Another object of the present invention is to provide a pressure-sensitive adhesive having a relatively low viscosity at the time of coating so that the amount of an organic solvent used is reduced, the solid content concentration is relatively high, and the coating suitability is good. And.

The hydroxyl-terminated urethane prepolymer-containing solution for the pressure-sensitive adhesive of the present invention
It contains a hydroxyl-terminated urethane prepolymer (UPH) which is a reaction product of one or more active hydrogen group-containing compounds (HX) having a plurality of active hydrogen groups in one molecule and one or more polyisocyanates (N). ,
The solid content concentration is 80% by mass or more, and the viscosity at 25 ° C. after standing at 25 ° C. for 1 hour immediately after preparation is 8000 mPa · s or less.

In the hydroxyl-terminated urethane prepolymer-containing solution for the pressure-sensitive adhesive of the present invention,
One or more active hydrogen group-containing compounds (HX) are preferably one or more polyols (HA) having a number average molecular weight of 1000 or more and a plurality of active hydrogens in one molecule having a number average molecular weight of less than 1000. Includes one or more active hydrogen group-containing compounds (HB) having a group.

The pressure-sensitive adhesive of the present invention contains the above-mentioned solution containing the hydroxyl-terminated urethane prepolymer of the present invention and the polyfunctional isocyanate compound (I).
The pressure-sensitive adhesive of the present invention preferably has a solid content concentration of 80% by mass or more, and has a viscosity of 5000 mPa · s or less at 25 ° C. after being allowed to stand at 25 ° C. for 3 hours immediately after preparation.
The pressure-sensitive adhesive sheet of the present invention includes a base material sheet and a pressure-sensitive adhesive layer made of a cured product of the above-mentioned pressure-sensitive adhesive of the present invention.

According to the present invention, it is possible to provide a hydroxyl-terminated urethane prepolymer-containing solution for a pressure-sensitive adhesive having a relatively high solid content concentration and a relatively low viscosity, while reducing the amount of organic solvent used.
According to the present invention, it is also provided to provide a pressure-sensitive adhesive having a relatively low viscosity at the time of coating so that the amount of the organic solvent used is reduced, the solid content concentration is relatively high, and the coating suitability is good. Can be done.

It is a schematic cross-sectional view of the pressure-sensitive adhesive sheet of 1st Embodiment which concerns on this invention. It is a schematic cross-sectional view of the adhesive sheet of the 2nd Embodiment which concerns on this invention.

The hydroxyl-terminated urethane prepolymer-containing solution for the pressure-sensitive adhesive of the present invention
It contains a hydroxyl-terminated urethane prepolymer (UPH) which is a reaction product of one or more active hydrogen group-containing compounds (HX) having a plurality of active hydrogen groups in one molecule and one or more polyisocyanates (N). ..
The pressure-sensitive adhesive of the present invention is a urethane-based pressure-sensitive adhesive containing the above-mentioned solution containing the hydroxyl-terminated urethane prepolymer of the present invention and the polyfunctional isocyanate compound (I).
The pressure-sensitive adhesive sheet of the present invention is a urethane-based pressure-sensitive adhesive sheet containing a base material sheet and a pressure-sensitive adhesive layer made of a cured product of the above-mentioned pressure-sensitive adhesive of the present invention.

The hydroxyl-terminated urethane prepolymer-containing solution for the pressure-sensitive adhesive of the present invention has a reduced amount of organic solvent used, a relatively high solid content concentration, and a relatively low viscosity. By using this hydroxyl-terminated urethane prepolymer-containing solution, the amount of organic solvent used is reduced, the solid content concentration is relatively high, and the viscosity is relatively low at the time of coating so as to have good coating suitability. The urethane-based pressure-sensitive adhesive of the present invention can be provided. The pressure-sensitive adhesive of the present invention uses a small amount of volatile organic compound (VOC) and is preferable from the viewpoint of environment and the like.

The hydroxyl-terminated urethane prepolymer-containing solution for the pressure-sensitive adhesive of the present invention has a solid content concentration of 80% by mass or more, and has a viscosity of 8000 mPa · s or less at 25 ° C. after being allowed to stand at 25 ° C. for 1 hour immediately after preparation. Is.
The pressure-sensitive adhesive of the present invention has a solid content concentration of preferably 70% by mass or more, more preferably 80% by mass or more, and particularly preferably 90% by mass or more. The pressure-sensitive adhesive of the present invention has a viscosity at 25 ° C. of preferably 8000 mPa · s or less, more preferably 7000 mPa · s or less, and particularly preferably 5000 mPa · s or less after being allowed to stand at 25 ° C. for 3 hours immediately after preparation. ..
The preferable viscosity region varies depending on the coating method, but the lower the viscosity, the better the coatability tends to be. The viscosity of the pressure-sensitive adhesive of the present invention changes with the passage of time immediately after preparation, but "viscosity at 25 ° C after standing at 25 ° C for 3 hours immediately after preparation" is assumed to be "viscosity at the time of coating". It is done.
In the present specification, unless otherwise specified, "solid content concentration" and "viscosity" shall be determined by the method described in the section of [Example].

[Adhesive]
(Hydroxyl-terminated urethane prepolymer-containing solution)
The hydroxyl-terminated urethane prepolymer-containing solution of the present invention is a copolymerization reaction of one or more active hydrogen group-containing compounds (HX) having a plurality of active hydrogen groups in one molecule and one or more polyisocyanates (N). This is a solution containing a hydroxyl group-terminated urethane prepolymer (UPH). The copolymerization reaction can be carried out in the presence of one or more catalysts, if necessary. One or more kinds of solvents can be used for the copolymerization reaction, if necessary.

In order to realize a high solid content concentration and a low viscosity of the pressure-sensitive adhesive, the hydroxyl-terminated urethane prepolymer (UPH) preferably has a lower molecular weight than the conventional general hydroxyl-terminated urethane prepolymer. The weight average molecular weight (Mw) of the hydroxyl-terminated urethane prepolymer (UPH) is preferably 10,000 to 100,000, more preferably 13,000 to 80,000. Mw is preferably 60,000 or less, more preferably 15,000 to 60,000, and particularly preferably 10,000 to 60,000.
In the present specification, "Mw" is a polystyrene-equivalent weight average molecular weight determined by gel permeation chromatography (GPC) measurement. "Mn" is a polystyrene-equivalent number average molecular weight determined by GPC measurement. These can be measured by the method described in the [Examples] section.

The hydroxyl-terminated urethane prepolymer-containing solution of the present invention has a solid content concentration of 80% by mass or more, preferably 85% by mass or more, more preferably 90% by mass or more, and particularly preferably 90% by mass or more, from the viewpoint of reducing VOC of the pressure-sensitive adhesive. It is 95% by mass or more.
From the viewpoint of the pot life of the pressure-sensitive adhesive and the coatability, the hydroxyl-terminated urethane prepolymer-containing solution of the present invention has a viscosity of 8000 mPa · s or less at 25 ° C. after being allowed to stand at 25 ° C. for 1 hour immediately after preparation. It is preferably 7,000 mPa · s or less, more preferably 6000 mPa · s or less, and particularly preferably 5000 mPa · s or less.
One or more active hydrogen group-containing compounds (HX) that are raw materials for hydroxyl-terminated urethane prepolymers (UPH) in order to improve the initial curability of the pressure-sensitive adhesive while achieving high solid content concentration and low viscosity of the pressure-sensitive adhesive. ) Means one or more polyols (HA) (relatively high molecular weight components) having a number average molecular weight of 1000 or more, and one or more having a plurality of active hydrogen groups in one molecule having a number average molecular weight of less than 1000. It is preferable to contain the active hydrogen group-containing compound (HB) (relatively low molecular weight component).
That is, the hydroxyl-terminated urethane prepolymer (UPH) includes one or more polyols (HA) having an Mn of 1000 or more and one or more active hydrogen group-containing compounds (HB) having an Mn of less than 1000. A hydroxyl-terminated urethane prepolymer (UPH-S), which is a reaction product of a plurality of types of active hydrogen group-containing compounds (HX) and one or more types of polyisocyanate (N), is preferable.
From the viewpoint of pot life and initial curability, one or more active hydrogen group-containing compounds (HX), which are raw materials for hydroxyl-terminated urethane prepolymers (UPH), have primary hydroxyl groups having appropriate reactivity as active hydrogen groups. It is preferable to include an active hydrogen group-containing compound containing the compound. In particular, it is preferable that at least one active hydrogen group-containing compound (HB) contains a primary hydroxyl group having appropriate reactivity as an active hydrogen group.

By adjusting the mass ratio of one or more polyols (HA), which is a relatively high molecular weight component, to one or more polyisocyanates (N), the weight average molecular weight (Mw) of the hydroxyl-terminated urethane prepolymer (UPH) Can be made relatively small, and a high solid content concentration and a low viscosity of the pressure-sensitive adhesive can be realized. In general, a hydroxyl-terminated urethane prepolymer (UPH) having a relatively low molecular weight tends to have poor initial curability. Therefore, as one of the raw materials for the hydroxyl-terminated urethane prepolymer (UPH), a relatively low molecular weight By using the active hydrogen group-containing compound (HB), the initial curability can be improved.
In addition to the above-mentioned effects, the effect of improving the wettability of the adhesive layer can be obtained by using a relatively high molecular weight polyol (HA) as one of the raw materials for the hydroxyl-terminated urethane prepolymer (UPH).
The decrease in viscosity of the pressure-sensitive adhesive and the improvement in wettability of the pressure-sensitive adhesive layer can also be realized by adding a plasticizer (P) to the pressure-sensitive adhesive. When a plasticizer (P) is used, a hydroxyl-terminated urethane prepolymer-containing solution containing the plasticizer (P) may be prepared and used to produce a pressure-sensitive adhesive, or a hydroxyl group not containing the plasticizer (P). A terminal urethane prepolymer-containing solution may be prepared and a plasticizer (P) may be used to prepare a pressure-sensitive adhesive. Since it is easy to achieve both high solid content and low viscosity of the hydroxyl-terminated urethane prepolymer-containing solution, a hydroxyl-terminated urethane prepolymer-containing solution containing a plasticizer (P) is prepared, and a pressure-sensitive adhesive is produced using the solution. Is preferable.
Further, by using a relatively low molecular weight active hydrogen group-containing compound (HB) as one of the raw materials of the hydroxyl-terminated urethane prepolymer (UPH), the effect of improving the removability of the adhesive layer can be obtained.

<Polyprethane (HA)>
The number average molecular weight (Mn) of the polyol (HA), which is a relatively high molecular weight component, is 1000 or more, preferably 1000 to 7000, more preferably 2000 to 6000, and particularly preferably 3000 to 5000. When Mn is 1000 or more, the cohesive force of the hydroxyl-terminated urethane prepolymer (UPH) becomes suitable, and the initial curability of the pressure-sensitive adhesive and the wettability of the pressure-sensitive adhesive layer become good. When Mn is 7,000 or less, the molecular weight of the hydroxyl-terminated urethane prepolymer (UPH) becomes suitable, and the pot life of the pressure-sensitive adhesive becomes good.

The type of polyol (HA) is not particularly limited, and examples thereof include polyester polyol, polyether polyol, polyacrylic polyol, polycaprolactone polyol, polycarbonate polyol, and castor oil-based polyol. Of these, polyester polyols, polyether polyols, and combinations thereof are preferable. From the viewpoint of the wettability of the adhesive layer, the one or more kinds of polyols (HA) more preferably contain a polyether polyol having an appropriate cohesive force.

As the polyester polyol, known ones can be used, and examples thereof include compounds (esterified products) obtained by an esterification reaction between one or more polyol components and one or more acid components.

As the polyol component of the raw material, ethylene glycol (EG), propylene glycol (PG), diethylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2-Butyl-2-ethyl-1,3-propanediol, 2,4-diethyl-1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 2-ethyl-1,3- Hexanediol, 1,8-octanediol, 1,9-nonanediol, 2-methyl-1,8-octanediol, 1,8-decanediol, octadecanediol, glycerin, trimethylolpropane, pentaerythritol, and hexanetriol. And so on.

The acid components of the raw material include succinic acid, methylsuccinic acid, adipic acid, piceric 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'-biphenyldicarboxylic acid , And these acid anhydrides and the like.

A known polyether polyol can be used, and a compound obtained by addition polymerization of one or more oxylan compounds using an active hydrogen-containing compound having two or more active hydrogens in one molecule as an initiator. (Additional polymer).

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

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

As the polyether polyol, an alkylene oxide adduct of an active hydrogen-containing compound (also referred to as "polyoxyalkylene polyol") is preferable. Of 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, and the like are preferable.

<Active hydrogen group-containing compound (HB)>
The number average molecular weight (Mn) of the active hydrogen group-containing compound (HB), which is a relatively low molecular weight component, is less than 1000, preferably 50 to 900, more preferably 50 to 300, and particularly preferably 50 to 200. .. As described above, in general, a hydroxyl-terminated urethane prepolymer (UPH) having a relatively low molecular weight tends to have poor initial curability, and therefore is compared as one of the raw materials for the hydroxyl-terminated urethane prepolymer (UPH). The initial curability can be improved by using an active hydrogen group-containing compound (HB) which is a target low molecular weight component.

Examples of the active hydrogen group include a hydroxy group, a mercapto group, an amino group (in the present specification, the amino group includes an imino group) and the like. As the active hydrogen group-containing compound (HB), a polyol having a plurality of hydroxy groups in one molecule, a polyamine having a plurality of amino groups in one molecule, an amino alcohol having an amino group and a hydroxyl group in one molecule, and one molecule. Examples thereof include polythiol having a plurality of mercapto groups. These can be used alone or in combination of two or more. The active hydrogen group-containing compound (HB) may be a non-polymer or a polymer.
Of these, polyols are preferred. Since polyamines and polythiols are highly reactive and have a short pot life, they are preferably used in combination with polyols. Further, when the polyol contains a secondary hydroxyl group, the initial curability of the urethane-based pressure-sensitive adhesive is not improved. Therefore, from the viewpoint of pot life and initial curability, the active hydrogen group-containing compound (HB) is suitable as an active hydrogen group. It is preferable to contain a reactive primary hydroxyl group, and it is more preferable to contain only a primary hydroxyl group as an active hydrogen group.

Examples of non-polymer polyols include ethylene glycol (EG), propylene glycol (PG), diethylene glycol, triethylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, and 1,5-pentanediol. , 3-Methyl-1,5-pentanediol, 2-butyl-2-ethyl-1,3-propanediol, 2,4-diethyl-1,5-pentanediol, 1,2-hexanediol, 1,6 -Hexanediol, 2-ethyl-1,3-hexanediol (also referred to as "1,3-octanediol"), 1,8-octanediol, 1,9-nonanediol, 2-methyl-1,8-octane Examples thereof include diols, 1,8-decanediols, octadecanediols, glycerin, trimethylolpropane (TMP), pentaerythritol, hexanetriol and the like.

Examples of the polymer polyol that can be used as the active hydrogen group-containing compound (HB) include polyester polyol, polyether polyol, polyacrylic polyol, polycaprolactone polyol, polycarbonate polyol, and castor oil-based polyol. Of these, polyester polyols, polyether polyols, and combinations thereof are preferable.

Examples of polyester polyols and polyether polyols are the same as those mentioned for polyols (HA).

Examples of polyamines that can be used as an active hydrogen group-containing compound (HB) include ethylenediamine, 1,2-propanediamine, 1,3-propanediamine, 1,4-butanediamine, 1,5-pentanediamine, and 1,6. -Hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonandiamine, 1,10-decanediamine, 1,12-dodecanediamine, 1,14-tetradecanediamine, 1,16-hexadecan Diamine, hexamethylenediamine, trimethylhexamethylenediamine, iminobispropylamine, methyliminobispropylamine, 1,5-diamino-2-methylpentane, isophoronediamine, 1,3-bisaminomethylcyclohexane, 1-cyclohexylamino- 3-Aminopropane, 3-aminomethyl-3,3,5-trimethyl-cyclohexylamine, dimethyleneamine with norbornan skeleton, metaxylylene diamine (MXDA), hexamethylenediamine carbamate, diethylenetriamine, triethylenetetramine, tetraethylenepenta Min, and aliphatic polyamines such as pentaethylenehexamine; 3,3'-dichloro-4,4'-diaminodiphenylmethane (MOCA), 4,4'-diaminodiphenylmethane, 2,4'-diaminodiphenylmethane, 3,3' -Diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 2,2'-diaminobiphenyl, 3,3'-diaminobiphenyl, 2,4-diaminophenol, 2,5-diaminophenol, o-phenylenediamine, m-phenylene Diamine, p-phenylenediamine, 2,3-tolylene diamine, 2,4-tolylene diamine, 2,5-tolylene diamine, 2,6-tolylene diamine, 3,4-tolylene diamine, and diethyltoluene Aromatic polyamines such as diamines; and the like.

Amino alcohols that can be used as active hydrogen group-containing compounds (HBs) include monoethanolamine, diethanolamine, 2-amino-2-methyl-1-propanol, tri (hydroxymethyl) aminomethane, and 2-amino-2. Examples thereof include monoamines having a hydroxyl group such as -ethyl-1,3-propanediol; diamines having a hydroxyl group such as N- (2-hydroxypropyl) ethanolamine; and the like.

Examples of polythiols that can be used as the active hydrogen group-containing compound (HB) include methanedithiol, 1,3-butanedithiol, 1,4-butanedithiol, 2,3-butanedithiol, 1,2-benzenedithiol, 1, 3-benzenedithiol, 1,4-benzenedithiol, 1,10-decandithiol, 1,2-ethanedithiol, 1,6-hexanedithiol, 1,9-nonandithiol, 1,8-octanedithiol, 1,5 -Pentanedithiol, 1,2-propanedithiol, 1,3-propadithiol, toluene-3,4-dithiol, 3,6-dichloro-1,2-benzenedithiol, 1,5-naphthalenedithiol, 1,2- Benzenedimethanethiol, 1,3-benzenedimethanethiol, 1,4-benzenedimethanethiol, 4,4'-thiobisbenzenethiol, 2,5-dimercapto-1,3,4-thiazazole, 1,8 -Dimercapto-3,6-dioxaoctane, 1,5-dimercapto-3-thiapentane, 2-di-n-butylamino-4,6-dimercapto-s-triazine, and thiol group-terminated polymers (polysulfide polymer, etc.) And so on.

The number of functional groups (number of hydroxyl groups) of one or more types of polyols (HA) is arbitrary, and a plurality of types of polyols (HA) having different numbers of functional groups may be used in combination, if necessary. Similarly, the number of functional groups (number of active hydrogen groups) of one or more active hydrogen group-containing compounds (HB) is arbitrary, and a plurality of types of active hydrogen group-containing compounds (HB) having different functional groups are used in combination as needed. You may.
One or more polyols (HA) can include bifunctional polyols and / or trifunctional or higher functional polyols. Similarly, one or more active hydrogen group-containing compounds (HBs) can include bifunctional active hydrogen group-containing compounds and / or trifunctional or higher functional hydrogen group-containing compounds. In general, a bifunctional active hydrogen group-containing compound has two-dimensional crosslinkability and can impart appropriate flexibility to the adhesive layer. The trifunctional or higher functional hydrogen group-containing compound has three-dimensional crosslinkability and can impart appropriate hardness to the adhesive layer. By selecting the number of functional groups (number of active hydrogen groups) of each of one or more polyols (HA) and one or more active hydrogen group-containing compounds (HB), the adhesive strength, cohesive strength, and re-aggregation of urethane adhesives Properties such as peelability can be adjusted. The number of functional groups of each material can be selected so that the properties such as adhesive strength, cohesive strength, and removability are in a preferable range depending on the application and the like.
Since it is easy to achieve both adhesive strength and removability, the one or more kinds of polyols (HA) preferably contain a trifunctional or higher functional polyol, and preferably contain a trifunctional or higher functional polyether polyol. Since it is easy to achieve both reaction stability and cohesive force, it is preferable that one or more active hydrogen group-containing compounds (HB) contain a bifunctional active hydrogen group-containing compound.

The plurality of active hydrogen group-containing compounds (HX), which are raw materials for the hydroxyl group-terminated urethane prepolymer (UPH), include known active hydrogen group-containing compounds other than the above-mentioned polyol (HA) and active hydrogen group-containing compound (HB). It may contain one or more kinds.

<Polyisocyanate (N)>
As the polyisocyanate (N), known ones can be used, and examples thereof include aromatic polyisocyanates, aliphatic polyisocyanates, and alicyclic polyisocyanates.

As aromatic polyisocyanates, 1,3-phenylenediocyanate, 4,4'-diphenyldiisocyanate, 1,4-phenylenediocyanate, 4,4'-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6-triisocyanate Range isocyanate, 4,4'-toluidin 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-diisocyanate, 1, , 4-Tetramethylxylylene diisocyanate, 1,3-tetramethylxylylene diisocyanate and the like.

Aliphatic polyisocyanates include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), pentamethylene diisocyanate, 1,2-propylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, and dodecamethylene diisocyanate. , And 2,4,4-trimethylhexamethylene diisocyanate.

Examples of the alicyclic polyisocyanate include isophorone diisocyanate (IPDI), 1,3-cyclopentane diisocyanate, 1,3-cyclohexanediisocyanate, 1,4-cyclohexanediisocyanate, methyl-2,4-cyclohexanediisocyanate, and methyl-2,6. Cyclohexanediisocyanate, 4,4′-methylenebis (cyclohexylisocyanate), 1,4-bis (isocyanatemethyl) cyclohexane and the like can be mentioned.

Other examples of the polyisocyanate include the trimethylolpropane adduct form, the biuret form, the allophanate form, and the trimer (the trimer contains an isocyanurate ring) of the above-mentioned polyisocyanate.

As the polyisocyanate (N), 4,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI) and the like are preferable. The details will be described later, but it is preferable that one or more kinds of polyisocyanates (N) contain isophorone diisocyanate (IPDI).

The preferred raw material compounding ratio of the hydroxyl-terminated urethane prepolymer (UPH) is as follows.
The ratio (NCO / H) of the number of moles of the isocyanate group (NCO) of the polyisocyanate (N) to the total number of moles of the active hydrogen group (H) of the plurality of active hydrogen group-containing compounds (HX) is 0.20. It is preferable to determine the raw material compounding ratio so as to be ~ 0.84, more preferably 0.40 to 0.80. The closer the NCO / H is to 1, the more likely it is to gel during the synthesis of the hydroxyl-terminated urethane prepolymer (UPH). When the NCO / H is 0.84 or less, gelation during synthesis of the hydroxyl-terminated urethane prepolymer (UPH) can be effectively suppressed.

From the viewpoint of improving the initial curability of the pressure-sensitive adhesive while achieving a high solid content concentration and low viscosity of the pressure-sensitive adhesive, one or more active hydrogen group-containing compounds with respect to 100 parts by mass of one or more types of polyol (HA). The amount of (HB) is preferably 0.5 to 40 parts by mass, more preferably 2 to 40 parts by mass, and particularly preferably 1 to 25 parts by mass.
From the viewpoint of improving the initial curability of the pressure-sensitive adhesive while achieving a high solid content concentration and low viscosity of the pressure-sensitive adhesive, one or more types of polyisocyanate (N) with respect to 100 parts by mass of one or more types of polyol (HA). The amount of is preferably 1 to 50 parts by mass, more preferably 3 to 30 parts by mass.

<Catalyst>
One or more catalysts can be used for the polymerization of the hydroxyl-terminated urethane prepolymer (UPH), if necessary. Known catalysts can be used, and examples thereof include tertiary amine compounds and organometallic compounds.
Examples of the tertiary amine compound include triethylamine, triethylenediamine, 1,8-diazabicyclo (5,4,0) -undecene-7 (DBU) and the like.
Examples of the organometallic compound include tin-based compounds and non-tin-based compounds.
Examples of tin compounds include dibutyltin dichloride, dibutyltin oxide, dibutyltin dibromide, dibutyltin dimalate, dibutyltin dilaurate (DBTDL), dibutyltin diacetate, dibutyltin sulfide, tributyltin sulfide, tributyltin oxide, and tributyltin acetate. , Triethyltin ethoxide, tributyltin ethoxide, dioctyltin dilaurate, dioctyltin oxide, tributyltin chloride, tributyltin trichloroacetate, tin 2-ethylhexanoate and the like.
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; 2 -Iron-based irons such as iron ethylhexanoate and iron acetylacetonate; cobalt-based such as cobalt benzoate and cobalt 2-ethylhexanoate; zinc-based such as zinc naphthenate and zinc 2-ethylhexanoate; zinc naphthenate and the like Zylon type can be mentioned.
The type and amount of the catalyst added can be appropriately designed within a range in which the reaction proceeds well.

When a plurality of types of active hydrogen group-containing compounds (HX) are used at the same time, gelation or cloudiness of the reaction solution may easily occur in a single catalyst system due to the difference in reactivity of each active hydrogen group-containing compound (HX). There is. In this case, by using two types of catalysts, the reaction (for example, reaction rate) can be easily controlled, and the above problem can be solved. The combination of the two types of catalysts is not particularly limited, and examples thereof include tertiary amine / organometallic, tin-based / non-tin-based, and tin-based / tin-based. It is preferably tin-based / tin-based, more preferably dibutyltin dilaurate and tin 2-ethylhexanoate.
The mass ratio of tin 2-ethylhexanoate to dibutyltin dilaurate (tin 2-ethylhexanoate / dibutyltin dilaurate) is not particularly limited, and is preferably more than 0 and less than 1, more preferably 0.2 to 0.6. is there. When the mass ratio is less than 1, the balance of catalytic activity is good, gelation and white turbidity of the reaction solution are effectively suppressed, and the polymerization stability is further improved.

<Solvent>
One or more kinds of solvents can be used for the polymerization of the hydroxyl-terminated urethane prepolymer (UPH), if necessary. Known solvents can be used, and generally, organic solvents such as methyl ethyl ketone, ethyl acetate, toluene, xylene, and acetone are used.
Since the hydroxyl-terminated urethane prepolymer-containing solution of the present invention can have a low viscosity even at a high solid content concentration, the amount of organic solvent used can be reduced. The content of the organic solvent in the hydroxyl-terminated urethane prepolymer-containing solution of the present invention is preferably 20% by mass or less, more preferably 10% by mass or less, and may be 0% by mass. The hydroxyl-terminated urethane prepolymer-containing solution of the present invention is preferable from the viewpoint of the environment because the amount of volatile organic compound (VOC) used is small.

<Manufacturing method of hydroxyl-terminated urethane prepolymer-containing solution>
The hydroxyl group-terminated urethane prepolymer-containing solution uses one or more catalysts as needed in the presence of one or more solvents as needed, and one or more active hydrogen group-containing compounds (HX) and one kind. It can be produced by subjecting the above polyisocyanate (N) to a copolymerization reaction. The polymerization method is not particularly limited, and known polymerization methods such as a massive polymerization method and a solution polymerization method can be applied. The polymerization reaction can be carried out in one step or a plurality of steps.
When a catalyst is used, the reaction temperature is preferably less than 100 ° C, more preferably 50 to 95 ° C, and particularly preferably 60 to 85 ° C. When the reaction temperature is 100 ° C. or higher, it becomes difficult to control the reaction rate, polymerization stability, etc., and it may be difficult to produce a hydroxyl-terminated urethane prepolymer (UPH) having a desired molecular weight. The reaction temperature when no catalyst is used is preferably 100 ° C. or higher, more preferably 110 ° C. or higher.

Hereinafter, it contains one or more polyols (HA) having an Mn of 1000 or more, preferably 1000 to 7000, and one or more active hydrogen group-containing compounds (HB) having an Mn of less than 1000, preferably 50 to 900. A preferred method for producing a hydroxyl-terminated urethane prepolymer (UPH-S), which is a reaction product of a plurality of types of active hydrogen group-containing compounds (HX) and one or more types of polyisocyanate (N), will be described.

As a polymerization procedure of the hydroxyl-terminated urethane prepolymer (UPH-S),
Procedure 1) One or more polyols (HA), one or more active hydrogen group-containing compounds (HB), one or more polyisocyanates (N), one or more catalysts if necessary, and optionally Procedure for charging one or more kinds of solvents into a flask at once;
Step 2) Charge one or more polyols (HA), one or more active hydrogen group-containing compounds (HB), one or more catalysts if necessary, and one or more solvents if necessary into a flask. Procedure for adding one or more kinds of polyisocyanate (N) dropwise to this;
Step 3) One or more polyols (HA), one or more polyisocyanates (N), one or more catalysts if necessary, and one or more solvents as needed are collectively charged into the flask. After reacting one or more polyisocyanates (N) with one or more polyols (HA) at an excess ratio of isocyanate groups to produce an isocyanate group-terminated urethane prepolymer (UPN-S), one or more types Procedure for adding the active hydrogen group-containing compound (HB) of the above; and the like.

In steps 1) and 2), a relatively high molecular weight polyol (HA) and a relatively low molecular weight active hydrogen group-containing compound (HB) are simultaneously mixed with the polyisocyanate (N). In this method, the highly reactive, relatively low molecular weight active hydrogen group-containing compound (HB) reacts preferentially with the polyisocyanate (N) over the less reactive, relatively high molecular weight polyol (HA). Tend. In this case, a relatively high molecular weight polyol (HA) having low reactivity may remain unreacted and the reaction solution may become cloudy. When the number of moles of isocyanate groups is excessive with respect to the total number of moles of active hydrogen groups in order to eliminate the relatively high molecular weight polyol (HA) that remains unreactive, the number of moles of isocyanate groups is relatively low. An undesired reaction between an isocyanate group-terminated urethane prepolymer produced by the first reaction of a group-containing compound (HB) and a polyisocyanate (N) with a highly reactive polyether polyol (HB) having a relatively low molecular weight. May occur and the reaction solution may gel.

Procedure 3) is preferable because the reaction is easy to control. Polymerization by this procedure is a step of reacting one or more types of polyol (HA) with one or more types of polyisocyanate (N) at an excess ratio of isocyanate groups to produce an isocyanate group-terminated urethane prepolymer (UPN). The step of reacting the obtained isocyanate group-terminated urethane prepolymer (UPN) with one or more active hydrogen group-containing compounds (HB) is included.

In step 3), only the relatively high-molecular-weight polyol (HA) having low reactivity is first reacted with the polyisocyanate (N) in a state where the relatively low-molecular-weight active hydrogen group-containing compound (HB) does not coexist. Then, the obtained isocyanate group-terminated urethane prepolymer (UPN) is reacted with the active hydrogen group-containing compound (HB). In this method, gelation and cloudiness of the reaction solution can be suppressed, and a desired hydroxyl-terminated urethane prepolymer (UPH-S) can be stably synthesized.
Therefore, the hydroxyl group-terminated urethane prepolymer (UPH-S) is an isocyanate group-terminated urethane prepolymer (UPN) which is a reaction product of a polyol (HA) and a polyisocyanate (N), and an active hydrogen group-containing compound (HB). It is preferably a reaction product with.
In step 3), it is preferable that one or more kinds of polyisocyanates (N) contain isophorone diisocyanate (IPDI). In this case, the reaction is easy to control, and a desired hydroxyl-terminated urethane prepolymer (UPH-S) can be stably synthesized.

(Polyfunctional isocyanate compound (I))
As the polyfunctional isocyanate compound (I), a known compound can be used, and the compound exemplified as the polyisocyanate (N) which is a raw material of the hydroxyl group-terminated urethane prepolymer (UPH) (specifically, aromatic polyisocyanate, aliphatic). Polyisocyanates, aromatic aliphatic polyisocyanates, alicyclic polyisocyanates, and trimethylolpropanadducts / biuret / allophanates / trimerics thereof can be used.

(Plasticizer (P))
The pressure-sensitive adhesive of the present invention may contain one or more plasticizers (P), if necessary. The plasticizer (P) can function as a diluent together with the solvent. By adding the plasticizer (P) to the pressure-sensitive adhesive of the present invention, low viscosity can be realized even at a high solid content concentration, which is preferable. When the pressure-sensitive adhesive of the present invention contains a plasticizer (P), the pressure-sensitive adhesive layer has good wettability with respect to an adherend such as glass, and a sticking interface is used when the pressure-sensitive adhesive sheet is adhered to the adherend. It is also possible to obtain the effect of suppressing the entrainment of air bubbles in the glass.
The amount of the plasticizer (P) with respect to 100 parts by mass of the hydroxyl-terminated urethane prepolymer (UPH) is preferably 0 to 200 parts by mass, and more preferably 20 to 200 parts by mass. The amount of the plasticizer (P) with respect to 100 parts by mass of the hydroxyl-terminated urethane prepolymer (UPH) is particularly preferably 50 to 200 parts by mass or 20 to 150 parts by mass, and most preferably 50 to 150 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 the ester of monobasic acid or polybasic acid and alcohol include isostearyl laurate, isopropyl myristate, isosetyl myristate, octyldodecyl myristate, isostearyl palmitate, isosetyl stearate, octyldodecyl oleate, and phthalate. Dibutyl acid, dioctyl phthalate, diheptyl phthalate, dibenzyl phthalate, butylbenzyl phthalate, diisodecyl adipate, diisostearyl adipate, dibutyl sebacate, diisocetyl sevacinate, tributyl acetylcitrate, tributyl trimellitic acid, trimerit Examples thereof include trioctyl acid, trihexyl trimellitic acid, trioleyl trimellitic acid, and triisocetyl trimellitic acid.

Examples of the ester 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, and ethylene glycol, propylene glycol, and glycerin. , Trimethylol propane, pentaerythritol, and esters with alcohols such as sorbitan.

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 diolarate, and dipolyethylene glycol methyl adipate. Examples include ether.

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

(Β-diketone compound (X))
The pressure-sensitive adhesive of the present invention may contain one or more β-diketone compounds (X), if necessary. The β-diketone compound (X) is not particularly limited, and is acetylacetone, 2,4-pentanedione, 3-methyl-2,4-pentanedione, 2,4-hexanedione, 1,3-cyclohexanedione, 2, 2-Dimethyl-3,5-hexanedione, 2,4-heptane, 3,5-heptane, 2,2,6,6-tetramethyl-3,5-heptane, 1,3-cycloheptane , 2,4-octanedione, 2,2,7-trimethyl-3,5-octanedione, 2,4-nonandione, 3-methyl-2,4-nonandione, 2-methyl-4,6-nonandione, 1, -Phenyl-1,3-butanedione, spirodecandion and the like can be mentioned. Of these, acetylacetone and the like are preferable. The β-diketone compound (X) such as acetylacetone functions as a curing retarder, and by adding it to the adhesive, the pot life can be satisfactorily adjusted.

(solvent)
The pressure-sensitive adhesive of the present invention may contain one or more kinds of solvents, if necessary. Known solvents can be used, and examples thereof include organic solvents such as methyl ethyl ketone, ethyl acetate, toluene, xylene, and acetone.
Since the pressure-sensitive adhesive of the present invention has a relatively high solid content concentration and a relatively low viscosity at the time of coating so as to have good coating suitability, the amount of organic solvent used can be reduced.
The content of the organic solvent in the pressure-sensitive adhesive of the present invention is preferably 20% by mass or less, more preferably 10% by mass or less, and may be 0% by mass. The pressure-sensitive adhesive of the present invention uses a small amount of volatile organic compound (VOC) and is preferable from the viewpoint of environment and the like.

(Anti-deterioration agent)
The pressure-sensitive adhesive of the present invention may contain one or more kinds of anti-deterioration agents, if necessary. As a result, deterioration of various properties due to long-term use of the adhesive layer can be suppressed. Examples of the anti-alteration agent include a hydrolysis resistant agent, an antioxidant, an ultraviolet absorber, a light stabilizer and the like.

<Hydrolytic agent>
When a hydrolysis reaction occurs in the adhesive layer in a high temperature and high humidity environment to generate a carboxy group, a hydrolysis resistant agent can be used to block the carboxy group. Examples of the hydrolysis resistant agent include carbodiimide-based, isocyanate-based, oxazoline-based, and epoxy-based. Of these, the carbodiimide type is preferable from the viewpoint of the hydrolysis inhibitory 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, examples of the diisocyanate include 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 thereof include 4,4'-dicyclohexylmethane diisocyanate and tetramethylxylylene diisocyanate. Examples of the carbodiimidization catalyst include 1-phenyl-2-phospholene-1-oxide, 3-methyl-2-phospholene-1-oxide, 1-ethyl-3-methyl-2-phospholene-1-oxide, and 1-ethyl-. Examples thereof include 2-phospholen-1-oxide and phospholen oxides such as these 3-phosphoren isomers.

Examples of the isocyanate-based hydrolysis inhibitor include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, m-phenylenedi isocyanate, p-phenylenedi isocyanate, 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'-biphenylenediisocyanate, 3,3'-dichloro-4, 4'-biphenylenediisocyanate, 1,5-naphthalenediocyanate, 1,5-tetrahydronaphthalenediocyanate, tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, dodecamethylene diisocyanate, trimethylhexamethylene diisocyanate, 1,3-cyclohexylene diisocyanate, 1,4-Cyclohexamethylene diisocyanate, xylylene diisocyanate, tetramethylximethylene diisocyanate, hydrogenated xylylene diisocyanate, lysine diisocyanis, isophorone diisocyanate, 4,4'-dicyclohexamethylene diisocyanate, and 3,3'-dimethyl-4,4 '-Dicyclohexamethylene diisocyanate and the like can be mentioned.

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'-ethylenebis (4-Methyl-2-oxazoline), 2,2'-diphenylenebis (2-oxazoline) and the like can be mentioned.

Examples of the epoxy-based hydrolyzate include diglycidyl ethers of aliphatic diols such as 1,6-hexanediol, neopentyl glycol, and polyalkylene glycol; sorbitol, sorbitan, polyglycerol, pentaerythritol, diglycerol, glycerol, etc. And polyglycidyl ethers of aliphatic polyols such as trimethylolpropane; polyglycidyl ethers of alicyclic polyols such as cyclohexanedimethanol; terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, trimellitic acid, adipic acid, sebacic acid and the like. Diglycidyl or polyglycidyl esters of aliphatic or aromatic polyvalent carboxylic acids; resorcinol, bis- (p-hydroxyphenyl) methane, 2,2-bis- (p-hydroxyphenyl) propane, tris- (p-) Diglycidyl ether or polyglycidyl ether of polyvalent phenols such as hydroxyphenyl) methane and 1,1,2,2-tetrakis (p-hydroxyphenyl) ethane; N, N-diglycidylaniline, N, N-diglycidyl. N-glycidyl derivatives of truidin and amines such as N, N, N', N'-tetraglycidyl-bis- (p-aminophenyl) methane; triglycidyl derivatives of aminophenols; triglycidyltris (2-hydroxyethyl) Isocyanurate and triglycidyl isocyanurate; examples thereof include epoxy resins such as orthocresol type epoxy resins and phenol novolac type epoxy resins.

The amount of the hydrolysis resistant agent added is not particularly limited, and is preferably 0.1 to 5 parts by mass, more preferably 0.2 to 4.5 parts by mass, based on 100 parts by mass of the hydroxyl-terminated urethane prepolymer (UPH). , Particularly preferably 0.5 to 3 parts by mass.

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

Examples of the phenolic compound include 2,6-di-t-butyl-p-cresol, butylated hydroxyanisol, 2,6-di-t-butyl-4-ethylphenol, and stear-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-t-butylphenol), 4,4'-butylidenebis (3-methyl-6-t-butylphenol), 3,9-bis [1,1-dimethyl-2- [Β- (3-t-Butyl-4-hydroxy-5-methylphenyl) propionyloxy] ethyl] 2,4,8,10-tetraoxaspiro [5,5] undecane, benzenepropanoic acid, 3,5- Bis (1,1-dimethylethyl) -4-hydroxy-, C7-C9 side chain alkyl ester, 1,1,3-tris (2-methyl-4-hydroxy-5-t-butylphenyl) butane, 1, 3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, tetrakis- [methylene-3- (3', 5'-di-t-butyl) -4'-Hydroxyphenyl) propionate] methane, bis [3,3'-bis- (4'-hydroxy-3'-t-butylphenyl) butyl acid] glycol ester, 1,3,5-tris (3) ', 5'-di-t-butyl-4'-hydroxybenzyl) -S-triazine-2,4,6- (1H, 3H, 5H) trione, tocopherol and the like can be mentioned.

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

Examples of phosphorus compounds include triphenylphosphite, diphenylisodecylphosphite, 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-Phenylphophenylanthrene-10-oxide, 10- (3,5-di-tert-butyl-4-hydroxybenzyl) -9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10 -Desiloxy-9,10-dihydro-9-oxa-10-phosphaphenanthrene, tris (2,4-di-tert-butylphenyl) phosphite, cyclic neopentanetetraylbis (2,4-di-tert) -Butylphenyl) phosphite, cyclic neopentanetetraylbis (2,6-di-tert-butyl-4-methylphenyl) phosphite, and 2,2-methylenebis (4,6-di-tert-butylphenyl) ) Octylphosphite and the like can be mentioned.

By using an antioxidant, it is possible to prevent thermal deterioration of the hydroxyl-terminated urethane prepolymer (UPH). In addition, bleeding out of the plasticizer (P) from the adhesive layer when the plasticizer (P) is used can be effectively suppressed.
The amount of the antioxidant added 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 3 parts by mass with respect to 100 parts by mass of the hydroxyl-terminated urethane prepolymer (UPH). Is 0.2 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 which are radical scavengers, and one or more phenolic compounds which are radical scavengers and a peroxide decomposing agent. It is more preferable to use one or more phosphorus compounds in combination. Further, as the antioxidant, it is particularly preferable to use a phenolic compound as a radical scavenger and a phosphorus compound as a peroxide decomposing agent in combination, and these antioxidants and the above-mentioned hydrolysis resistant agent in combination. ..

<UV absorber>
Examples of the ultraviolet absorber include benzophenone compounds, benzotriazole compounds, salicylic acid compounds, oxalic acid anilide compounds, cyanoacrylate compounds, triazine compounds and the like.
The amount of the ultraviolet absorber added is not particularly limited, and is preferably 0.01 to 3 parts by mass, more preferably 0.1 to 2.5 parts by mass, based on 100 parts by mass of the hydroxyl-terminated urethane prepolymer (UPH). Particularly preferably, it is 0.2 to 2 parts by mass.

<Light stabilizer>
Examples of the light stabilizer include hindered amine compounds and hindered piperidine compounds. The amount of the light stabilizer added is not particularly limited, and is preferably 0.01 to 2 parts by mass, more preferably 0.1 to 1.5 parts by mass, based on 100 parts by mass of the hydroxyl-terminated urethane prepolymer (UPH). Particularly preferably, it is 0.2 to 1 part by mass.

(Antistatic agent (AS agent))
The pressure-sensitive adhesive of the present invention may contain one or more antistatic agents (AS agents), if necessary. Examples of the antistatic agent include inorganic salts, polyhydric alcohol compounds, ionic liquids, ionic solids, and surfactants, and among them, ionic liquids and / or ionic solids are preferable. The "ionic liquid" is also called a room temperature molten salt, which is a salt having fluidity at 25 ° C.

Examples of the inorganic salt 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 and sodium nitrate. , Sodium carbonate, sodium thiocyanate and the like.

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

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

Examples of the ionic liquid containing pyridinium ions include 1-methylpyridinium bis (trifluoromethylsulfonyl) imide, 1-butylpyridinium bis (trifluoromethylsulfonyl) imide, 1-hexylpyridinium bis (trifluoromethylsulfonyl) imide, and the like. 1-octylpyridinium bis (trifluoromethylsulfonyl) imide, 1-hexyl-4-methylpyridiniumbis (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-methylpyridinium bis (perfluorobutylsulfonyl) ) Imid and the like.

Examples of the ionic liquid containing ammonium ions include trimethylheptyl ammoniumbis (trifluoromethanesulfonyl) imide, N, N-diethyl-N-methyl-N-propylammonium bis (trifluoromethanesulfonyl) imide, and 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 Examples include imide.

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

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

Examples of the ion solid containing an alkali metal ion include lithium bisfluorosulfonylimide, lithium bistrifluoromethylsulfonylimide, lithium bispentafluoroethylsulfonylimide, lithiumbisheptafluoropropylsulfonylimide, lithiumbisnonanfluorobutylsulfonylimide, and sodiumbis. Fluorosulfonylimide, sodium bistrifluoromethylsulfonylimide, sodium bispentafluoroethylsulfonylimide, sodium bisheptafluoropropylsulfonylimide, sodium bisnonan fluorobutylsulfonylimide, potassium bisfluorosulfonylimide, potassium bistrifluoromethylsulfonylimide, potassium bis Examples thereof include pentafluoroethyl sulfonyl imide, potassium bisheptafluoropropyl sulfonyl imide, and potassium bisnonan fluorobutyl sulfonyl imide.

Examples of ionic solids containing phosphonium ions include tetrabutylphosphonium bisfluorosulfonylimide, tetrabutylphosphonium bistrifluoromethylsulfonylimide, tetrabutylphosphonium bispentafluoroethylsulfonylimide, tetrabutylphosphonium bisheptafluoropropylsulfonylimide, and tetrabutyl. Phosphonium bisnonan fluorobutylsulfonylimide, tributylhexadecylphosphonium bisfluorosulfonylimide, tributylhexadecylphosphonium bistrifluoromethylsulfonylimide, tributylhexadecylphosphonium bispentafluoroethylsulfonylimide, tributylhexadecylphosphonium bisheptafluoropropylsulfonylimide, tributyl Hexadecylphosphonium bisnonan fluorobutylsulfonylimide, tetraoctylphosphonium bisfluorosulfonylimide, tetraoctylphosphonium bistrifluoromethylsulfonylimide, tetraoctylphosphonium bispentafluoroethylsulfonylimide, tetraoctylphosphonium bisheptafluoropropylsulfonylimide, and tetraoctyl Examples thereof include phosphonium bisnonan fluorobutylsulfonylimide.

Examples of ionic solids containing pyridinium ions include 1-hexadecyl-4-methylpyridinium bisfluorosulfonylimide, 1-hexadecyl-4-methylpyridinium bistrifluoromethylsulfonylimide, and 1-hexadecyl-4-methylpyridinium bispentafluoroethyl. Examples thereof include sulfonylimide, 1-hexadecyl-4-methylpyridinium bisheptafluoropropylsulfonylimide, and 1-hexadecyl-4-methylpyridinium bisnonanfluorobutylsulfonylimide.

Examples of ionic solids containing ammonium ions include lauryltrimethylammonium chloride, tributylmethylbistrifluoromethylsulfonylimide, tributylmethylbispentafluoroethylsulfonylimide, tributylmethylbisheptafluoropropylsulfonylimide, and tributylmethylmubisnonanfluorobutylsulfonyl. Imid, octyl tributyl bistrifluoromethyl sulfonylimide, octyl rebutyl bispentafluoroethyl sulfonylimide, octyl rebutyl bisheptafluoropropyl sulfonylimide, octyl rebutyl mubisnonan fluorobutyl sulfonylimide, tetrabutyl bisfluorosulfonylimide, tetrabutyl bistrifluoromethyl Examples thereof include sulfonylimide, tetrabutylbispentafluoroethylsulfonylimide, tetrabutylbisheptafluoropropylsulfonylimide, and tetrabutylmubisnonan fluorobutylsulfonylimide.

In addition, known ionic solids whose cations are pyrrolidinium ion, imidazolium ion, sulfonium ion and the like can be appropriately used.

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

Examples of the nonionic low molecular weight surfactant include glycerin fatty acid ester, polyoxyalkylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl amine, polyoxyethylene alkyl amine fatty acid ester, and fatty acid diethanolamide. Be done.
Examples of anionic low-molecular-weight surfactants include alkyl sulfonates, alkylbenzene sulfonates, and alkyl phosphates.
Examples of the cationic low molecular weight surfactant include tetraalkylammonium salts and trialkylbenzylammonium salts.
Examples of the amphoteric low molecular weight surfactant include alkyl betaine and alkyl imidazolium betaine.

Examples of the nonionic polymer surfactant include a polyether ester amide type, an ethylene oxide-epichlorohydrin type, and a 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 alkylaminopropionate, higher alkyldimethylbetaine, and betaine-type amphoteric surfactants such as higher alkyldihydroxyethyl betaine.

The amount of the antistatic agent added 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 hydroxyl-terminated urethane prepolymer (UPH).

(Leveling agent)
The pressure-sensitive adhesive of the present invention may contain a leveling agent, if necessary. 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-based leveling agent, and a silicone-based leveling agent. From the viewpoint of suppressing adhesion contamination after re-peeling of the adhesive sheet, an acrylic-based leveling agent or the like 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 contamination of the surroundings is suppressed. When Mw is 20,000 or less, the effect of improving the leveling property of the adhesive layer is effectively exhibited.

The amount of the leveling agent added is not particularly limited, and is preferable with respect to 100 parts by mass of the hydroxyl-terminated urethane prepolymer (UPH) from the viewpoint of suppressing adherent contamination after re-peeling the adhesive sheet and improving the leveling property of the adhesive layer. It is 0.001 to 2 parts by mass, more preferably 0.01 to 1.5 parts by mass, and particularly preferably 0.1 to 1 part by mass.

(Other optional ingredients)
The pressure-sensitive adhesive of the present invention may contain other optional components, if 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, conductivity. Examples thereof include agents, silane coupling agents, lubricants, corrosion inhibitors, heat-resistant stabilizers, weather-resistant stabilizers, polymerization inhibitors, defoaming agents and the like.

(Mixing ratio)
The pressure-sensitive adhesive of the present invention contains one or more hydroxyl-terminated urethane prepolymers (UPH) and one or more polyfunctional isocyanate compounds (I) as essential components, and further contains one or more optional components as necessary. .. These compounding ratios are not particularly limited, but preferable compounding ratios are as follows.
The amount of one or more polyfunctional isocyanate compounds (I) with respect to 100 parts by mass of one or more hydroxyl-terminated urethane prepolymers (UPH) is preferably 1 to 30 parts by mass, more preferably 3 to 20 parts by mass. When the amount of one or more polyfunctional isocyanate compounds (I) is 3 parts by mass or more, the cohesive force of the adhesive layer is good, and when it is 20 parts by mass or less, the pot life is good.

(Adhesive manufacturing method)
The method for producing the pressure-sensitive adhesive of the present invention is not particularly limited.
One or more polyfunctional isocyanate compounds (I) and, if necessary, one or more optional components are added and mixed with a hydroxyl-terminated urethane prepolymer-containing solution synthesized by a one-step or multiple-step copolymerization reaction. As a result, the pressure-sensitive adhesive of the present invention can be produced.

[Adhesive sheet]
The pressure-sensitive adhesive sheet of the present invention includes a base material sheet and a pressure-sensitive adhesive layer made of a cured product of the above-mentioned pressure-sensitive adhesive of the present invention. The adhesive layer can be formed on one side or both sides of the base 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 adhesive sheet is attached to the adherend.

FIG. 1 shows a schematic cross-sectional view of the pressure-sensitive adhesive sheet according to the first embodiment of the present invention. In FIG. 1, reference numeral 10 is an adhesive sheet, reference numeral 11 is a base material 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 an pressure-sensitive adhesive layer is formed on one side of the base material sheet.
FIG. 2 shows a schematic cross-sectional view of the pressure-sensitive adhesive sheet according to the second embodiment of the present invention. 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 base sheet is not particularly limited, and examples thereof include a resin sheet, paper, and a metal foil. 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. If necessary, the surface of the base sheet on the side where the adhesive layer is formed may be subjected to an easy-adhesion treatment such as a corona discharge treatment and an anchor coating agent application.

The constituent resin of the resin sheet is not particularly limited, and is an ester resin such as polyethylene terephthalate (PET); an olefin resin such as polyethylene (PE) and polypropylene (PP); a vinyl resin such as polyvinyl chloride; nylon 66 and the like. Amid resin; urethane resin (including foam); a combination thereof and the like can be mentioned.
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 the 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.

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 applied to the surface of a base sheet such as a resin sheet or paper can be used.

The adhesive sheet can be produced by a known method.
First, the pressure-sensitive adhesive of the present invention is applied to the surface of the base material 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 heating and drying temperature is not particularly limited, and is preferably about 60 to 150 ° C. The thickness of the adhesive layer (thickness after drying) varies depending on the application, but is preferably 0.1 to 200 μm.
Next, if necessary, a release sheet is attached to the exposed surface of the adhesive layer by a known method.
As described above, the single-sided adhesive sheet can be manufactured.
By performing the above operation on both sides, a double-sided adhesive sheet can be manufactured.

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

The method for producing the pressure-sensitive adhesive sheet is preferably a coating step of applying a pressure-sensitive adhesive on the base material sheet and heating to heat-dry the formed coating layer to form a pressure-sensitive adhesive layer containing a cured product of the pressure-sensitive adhesive. It includes a step, a winding step of winding the obtained adhesive sheet around a winding core to form an adhesive sheet roll, and a curing step of curing the adhesive sheet roll.

As described above, according to the present invention, a hydroxyl-terminated urethane prepolymer-containing solution for a pressure-sensitive adhesive, which has a reduced amount of organic solvent used, a relatively high solid content concentration, and a relatively low viscosity, is provided. can do. According to the present invention, the solid content concentration is 80% by mass or more, preferably 85% by mass or more, particularly preferably 90% by mass or more, most preferably 95% by mass or more, and allowed to stand at 25 ° C. for 1 hour immediately after preparation. A hydroxyl-terminated urethane prepolymer-containing solution for an adhesive having a viscosity at 25 ° C. of 8000 mPa · s or less, preferably 7000 mPa · s or less, more preferably 6000 mPa · s or less, and particularly preferably 5000 mPa · s or less. Can be provided.

According to the present invention, it is also provided to provide a pressure-sensitive adhesive having a relatively low viscosity at the time of coating so that the amount of the organic solvent used is reduced, the solid content concentration is relatively high, and the coating suitability is good. Can be done. According to the present invention, the solid content concentration is preferably 70% by mass or more, more preferably 80% by mass or more, particularly preferably 90% by mass or more, and 25 ° C. after standing at 25 ° C. for 3 hours immediately after preparation. It is possible to provide a pressure-sensitive adhesive having a viscosity of preferably 8000 mPa · s or less, more preferably 7000 mPa · s or less, and particularly preferably 5000 mPa · s or less. Good coating suitability can be obtained when the viscosity at 25 ° C. after standing at 25 ° C. for 3 hours immediately after preparation is within the above range.

In order to realize a high solid content concentration and a low viscosity of the pressure-sensitive adhesive, the hydroxyl-terminated urethane prepolymer (UPH) used in the present invention preferably has a lower molecular weight than the conventional general hydroxyl-terminated urethane prepolymer.
The hydroxyl-terminated urethane prepolymer (UPH) has a Mn of 1000 or more, preferably 1000 to 7000, in order to improve the initial curability of the pressure-sensitive adhesive while achieving a high solid content concentration and a low viscosity of the pressure-sensitive adhesive. A plurality of active hydrogen group-containing compounds (HX) containing one or more polyols (HA) and one or more active hydrogen group-containing compounds (HB) having an Mn of less than 1000, preferably 50 to 900. A hydroxyl group-terminated urethane prepolymer (UPH-S) which is a reaction product with one or more kinds of polyisocyanates (N) is preferable.

By adjusting the mass ratio of one or more polyols (HA), which is a relatively high molecular weight component, to one or more polyisocyanates (N), the number average molecular weight (Mn) of the hydroxyl-terminated urethane prepolymer (UPH) Can be made relatively small, and a high solid content concentration and a low viscosity of the pressure-sensitive adhesive can be realized. In general, a hydroxyl-terminated urethane prepolymer (UPH) having a relatively low molecular weight tends to have poor initial curability, and therefore has a relatively low molecular weight as one of the raw materials for the hydroxyl-terminated urethane prepolymer (UPH). By using the active hydrogen group-containing compound (HB), the initial curability can be improved. Further, preferably, by using an active hydrogen group-containing compound (HB) containing a primary hydroxyl group having appropriate reactivity, pot life and initial curability can be improved.
If the pot life of the pressure-sensitive adhesive is good, the viscosity of the pressure-sensitive adhesive does not become too high before the pressure-sensitive adhesive is applied on the base sheet, and the pressure-sensitive adhesive can be uniformly applied. If the initial curability of the pressure-sensitive adhesive is good, the coating layer or the pressure-sensitive adhesive layer receives hot air during heating and drying of the coating layer, or mechanical stress during winding and curing of the pressure-sensitive adhesive sheet obtained after heating and drying. It is difficult to be affected by the above, and it is possible to suppress the occurrence of surface appearance defects such as winding core step marks, citron skin, and curl on the adhesive layer.

In addition to the above-mentioned effects, the effect of improving the wettability of the adhesive layer can be obtained by using a relatively high molecular weight polyol (HA) as one of the raw materials for the hydroxyl-terminated urethane prepolymer (UPH). Further, by using a relatively low molecular weight active hydrogen group-containing compound (HB) as one of the raw materials of the hydroxyl-terminated urethane prepolymer (UPH), the effect of improving the removability of the adhesive layer can be obtained.
If the wettability of the adhesive layer is good, it is possible to prevent air bubbles from being caught in the adhesion interface when the adhesive sheet is attached to an adherend such as glass. If the adhesive layer has good re-peelability, the adherent contamination in which the adhesive component remains on the surface of the adherend after the adhesive sheet is re-peeled can be effectively suppressed.

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

Hereinafter, production examples, examples according to the present invention, and comparative examples will be described. In the following description, unless otherwise specified, "parts" means parts by mass, "%" means mass%, and "RH" means relative humidity.

[Evaluation items and evaluation methods]
The evaluation items and evaluation methods are as follows.
(Mn, Mw)
The number average molecular weight (Mn) and weight average molecular weight (Mw) of the urethane prepolymer were measured by the gel permeation chromatography (GPC) method. The measurement conditions were as follows. Both Mn and Mw are polystyrene-equivalent values.
<Measurement conditions>
Equipment: SHIMADZU Prominence (manufactured by Shimadzu Corporation),
Column: Two TOSOH TSKgel GMHs are connected in series,
Detector: Differential Refractometer Detector (RID-10A),
Solvent: tetrahydrofuran (THF),
Flow velocity: 1 mL / min,
Solvent temperature: 40 ° C,
Sample concentration: 0.1%,
Sample injection volume: 100 μL.

(Viscosity at 25 ° C)
To measure the viscosity of urethane prepolymer-containing solutions, polyol-containing solutions, and adhesives at 25 ° C, place the sample in a glass bottle with a lid, immerse the glass bottle in a constant temperature water bath at 25 ° C, and remove it after a predetermined time. This was carried out using a B-type viscometer (“TVB10 type viscometer” manufactured by Toki Sangyo Co., Ltd.).
The urethane prepolymer-containing solution and the polyol-containing solution were immediately placed in a glass bottle with a lid and immersed in a constant temperature water bath at 25 ° C., and then the viscosity was measured 1 hour later.
The pressure-sensitive adhesive was immediately placed in a glass bottle with a lid and immersed in a constant temperature water bath at 25 ° C., and the measurement was carried out 3 hours later. The viscosity 3 hours after the preparation is assumed to be the "viscosity at the time of coating".
In the actual manufacturing method of the pressure-sensitive adhesive sheet, the time from immediately after the preparation of the pressure-sensitive adhesive to the coating is not particularly limited, and from the viewpoint of optimizing the viscosity at the time of coating the pressure-sensitive adhesive, it is preferably within 6 hours. It is preferably within 3 hours.

(Solid content concentration)
The solid content concentration of the urethane prepolymer-containing solution, the polyol-containing solution, and the pressure-sensitive adhesive was determined from the mass change after drying after heating and drying about 1 g of the sample at 120 ° C. for 20 minutes.

(VOC reduction effect of adhesive)
The solid content concentration of the pressure-sensitive adhesive was measured by the above method, and the VOC reduction effect of the pressure-sensitive adhesive was evaluated. It can be said that the higher the solid content concentration, the lower the amount of the organic solvent used, and the higher the effect of reducing the volatile organic compounds (VOC). The evaluation criteria are as follows.
⊚: Solid content concentration is 90% by mass or more, excellent.
◯: The solid content concentration is 80% by mass or more and less than 90% by mass, which is good.
Δ: Solid content concentration is 70% by mass or more and less than 80% by mass, practically usable.
X: Solid content concentration is less than 70% mass, not practical.

(Pot life)
The pressure-sensitive adhesive immediately after preparation was placed in a glass bottle with a lid, and the glass bottle was immersed in a constant temperature water bath at 25 ° C., and the viscosities were measured 1 hour and 6 hours after the start of immersion, respectively. The rate of increase in viscosity after 6 hours with respect to 1 hour (viscosity after 6 hours / viscosity after 1 hour [times]) was determined. The evaluation criteria are as follows.
⊚: Viscosity increase rate is less than 200%, excellent.
◯: The viscosity increase rate is 200% or more and less than 300%, which is good.
Δ: Viscosity increase rate is 300% or more and less than 400%, practically possible.
X: Viscosity increase rate is 400% or more, not practical.

(Initial curability)
In each of Examples 1 to 54 and Comparative Examples 1 to 4, the adhesive sheet obtained by applying an adhesive on the base sheet and drying the adhesive sheet was cured in an atmosphere of 23 ° C.-50% RH for 3 hours. A sample (adhesive sheet cured for 3 hours) and a sample cured for 120 hours in an atmosphere of 23 ° C. to 50% RH (adhesive sheet cured for 120 hours) were prepared.
For each sample, the gel fraction (mass%) was calculated as follows.
A test piece having a width of 30 mm and a length of 100 mm was cut out from the adhesive sheet after curing for a predetermined time, and this was attached to a SUS mesh (opening: 0.077 mm, wire diameter: 0.05 mm). This was immersed in ethyl acetate, extracted at 50 ° C. for 24 hours, dried at 100 ° C. for 30 minutes, and the gel fraction (mass%) was calculated based on the following formula (1).
Gel fraction (mass%) = (G2 / G1) x 100 ... (1)
In the above formula, each reference numeral indicates the following parameters.
G1: Mass of adhesive layer before extraction with ethyl acetate,
G2: Mass of the adhesive layer after extraction with ethyl acetate and drying.
Further, based on the following formula (2), the gel fraction change rate between the 3-hour curing and the 120-hour curing was calculated.
Gel fraction change rate (%) = (H1 / H2) x 100 ... (2)
In the above formula, each reference numeral indicates the following parameters.
H1: 3 hours curing Gel fraction of the adhesive layer of the adhesive sheet,
H2: Gel fraction of the adhesive layer of the 120-hour curing adhesive sheet.
The evaluation criteria are as follows.
◯: The gel fraction change rate is 70% or more, which is good.
Δ: The gel fraction change rate is 30% or more and less than 70%, which is practical.
X: Gel fraction change rate is less than 30%, not practical.

(Wetness)
In each of Examples 1 to 54 and Comparative Examples 1 to 4, the adhesive sheet obtained by applying an adhesive on the base sheet and drying it was cured in an atmosphere of 23 ° C.-50% RH for 120 hours. Then, a test piece having a width of 50 mm and a length of 100 mm was cut out from the adhesive sheet, left for 30 minutes in an atmosphere of 23 ° C. to 50% RH, and then the release sheet was peeled off from the test piece. One end in the longitudinal direction of the test piece from which the release sheet was peeled off was fixed to the end of the glass plate, and the other end that was not fixed was manually lifted to a position 5 cm in height from the surface of the glass plate. In this state, the hand was released, and the time until the entire adhesive layer (length 100 mm) adhered to the surface of the glass plate was measured. The evaluation criteria are as follows.
◯: It takes less than 3 seconds for the entire adhesive layer to adhere, which is good.
Δ: It takes 3 seconds or more and less than 6 seconds for the entire adhesive layer to adhere, which is practical.
X: It takes more than 6 seconds for the entire adhesive layer to adhere, which is not practical.

(Removability)
In each of Examples 1 to 54 and Comparative Examples 1 to 4, the adhesive sheet obtained by applying an adhesive on the base sheet and drying it was cured in an atmosphere of 23 ° C.-50% RH for 120 hours. After that, two test pieces having a width of 70 mm and a length of 100 mm were cut out from the adhesive sheet. For each of the two test pieces, the release sheet was peeled off in an atmosphere of 23 ° C. to 50% RH, a caustic soda glass plate was attached to the surface of the exposed adhesive layer, and the two test pieces were pressure-bonded with a laminator. The two obtained laminates were left to stand for 72 hours (condition 1) and 120 hours (condition 2), respectively, in an oven set at 60 ° C.-90% RH. After heating in the oven for a predetermined time, the two laminates are taken out, air-cooled in an atmosphere of 23 ° C.-50% RH for 3 hours, and then the adhesive sheet is peeled off from the glass plate to visually observe the re-peeling property. Evaluated. The evaluation criteria are as follows.
◯: Excellent, with no adhesive layer component adhering to the glass surface under all conditions.
Δ: Under condition 1, the adhesive layer component does not adhere to the glass surface at all, but under condition 2, the adhesive layer component adheres to the glass surface, which is practical.
X: Adhesion of the adhesive layer component to the glass surface occurs under all conditions, which is not practical.

[material]
The materials used are as follows.
<Polyprethane (HA) having a number average molecular weight (Mn) of 1000 or more>
(HA-1): Kuraray polyol P-1010 (abbreviation in the table: P-1010), Kuraray bifunctional polyester polyol, Mn1000, number of hydroxyl groups 2, hydroxyl value 112,
(HA-2): Kuraray polyol F-3010 (abbreviation in the table: F-3010), Kuraray trifunctional polyester polyol, Mn3000, number of hydroxyl groups 3, hydroxyl value 56,
(HA-3): PEG-1000, manufactured by Sanyo Chemical Industries, Ltd., bifunctional polyether polyol (polyethylene glycol), Mn1000, number of hydroxyl groups 2, hydroxyl value 112,
(HA-4): Poly bd, Idemitsu Kosan Co., Ltd., bifunctional polyolefin polyol, Mn2800, number of hydroxyl groups 2, hydroxyl value 40,
(HA-5): PP-2000, manufactured by Sanyo Chemical Industries, Ltd., bifunctional polyether polyol, Mn2000, number of hydroxyl groups 2, hydroxyl value 56,
(HA-6): Exenol 5030 (abbreviation in the table: EXCE5030), trifunctional polyether polyol manufactured by Asahi Glass Co., Ltd., Mn5100, number of hydroxyl groups 3, hydroxyl value 33,
(HA-7): Exenol 851 (abbreviation in the table: EXCE851), trifunctional polyether polyol manufactured by Asahi Glass Co., Ltd., Mn6700, number of hydroxyl groups 3, hydroxyl value 25.

(HA-8): Preminol S4013F (abbreviation in the table: PREM S4013F), bifunctional polyether polyol manufactured by Asahi Glass Co., Ltd., Mn12000, number of hydroxyl groups 2, hydroxyl value 9,
(HA-9): Preminol S3011 (abbreviation in the table: PREM S3011), trifunctional polyether polyol manufactured by Asahi Glass Co., Ltd., Mn10000, number of hydroxyl groups 3, hydroxyl value 17.

<Active hydrogen group-containing compound (HB) having a number average molecular weight (Mn) of less than 1000>
(HB-1): Contains only ethylene glycol (EG) and a primary hydroxyl group,
(HB-2): Contains only 1,5-pentanediol and primary hydroxyl groups,
(HB-3): 2-ethyl-1,3-hexanediol (also referred to as 1,3-octanediol), containing a primary hydroxyl group and a secondary hydroxyl group.
(HB-4): PPG200 (number indicates Mn, the same applies to PEG), polypropylene glycol, manufactured by Sanyo Kasei Co., Ltd., containing only secondary hydroxyl groups,
(HB-5): PEG300, polyethylene glycol, manufactured by Sanyo Chemical Industries, Ltd., containing only primary hydroxyl groups,
(HB-6): PEG600, polyethylene glycol, manufactured by Sanyo Chemical Industries, Ltd., containing only primary hydroxyl groups,
(HB-7): Contains glycerin, primary hydroxyl group and secondary hydroxyl group,
(HB-8): trimethylolpropane (TMP), containing only primary hydroxyl groups,
(HB-9): 1-methylamino-2,3-propanediol (MAPD), manufactured by Tokyo Chemical Industry Co., Ltd., contains a trifunctional amino group-containing polyol, Mn105, a primary hydroxyl group, a secondary hydroxyl group, and an amino group.

<Polyisocyanate (N)>
(N-1): Isophorone diisocyanate (IPDI), manufactured by Tokyo Chemical Industry Co., Ltd.,
(N-2): Hexamethylene diisocyanate (HDI), manufactured by Tokyo Chemical Industry Co., Ltd.,
(N-3): Tolylene diisocyanate (mixture of 2,4-tolylene diisocyanate (80% by mass) and 2,6-tolylene diisocyanate (20% by mass)) (TDI), manufactured by Tosoh Corporation.

<Organic solvent (B)>
(B-1): Ethyl acetate, manufactured by Daicel.

<Plasticizer (P)>
(P-1): Maleic acid ester plasticizer, DOM (dioctyl maleate), manufactured by Daihachi Chemical Co., Ltd.,
(P-2): Orthophosphate ester plasticizer, TOP (squirrel (2-ethylhexyl) phosphate), manufactured by Daihachi Chemical Co., Ltd.,
(P-3): Polyester ester-based plasticizer, RS-700, manufactured by ADEKA CORPORATION.

<Antioxidant (D)>
(D-1): IRGANOX 1135, manufactured by BASF.

<β-diketone compound (X) (curing retarder)>
(X-1): Acetylacetone, manufactured by Tokyo Chemical Industry Co., Ltd.

<Antistatic agent (AS agent) (F)>
(F-1): Elexel AS-804, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.

<Polyfunctional isocyanate compound (I)>
(I-1) Sumijour N-3300, manufactured by Sumika Bayer Urethane, hexamethylene diisocyanate (HDI) / isocyanurate, solid content 100% by mass,
(I-2): Coronate HL, manufactured by Tosoh Corporation, hexamethylene diisocyanate (HDI) / trimethylolpropane (TMP) adduct, solid content 75% by mass,
(I-3): Death module Z4470BA, manufactured by Sumika Bayer Urethane, isophorone diisocyanate (IPDI) / isocyanurate, solid content 70% by mass.

[Manufacturing of urethane prepolymer-containing solution or polyol-containing solution]
(Production Example 1) (Two-stage polymerization method)
In a 4-neck flask equipped with a stirrer, a reflux condenser, a nitrogen introduction tube, a thermometer, and a dropping funnel, 100 parts by mass of polyol (HA-1), 40 parts by mass of polyisocyanate (N-1), as a diluent. 10 parts by mass of the organic solvent (B-1), 100 parts by mass of the plasticizer (P-1), and 0.01 parts by mass of dioctyltin dilaurate as a catalyst were charged and mixed. The content was gradually heated to 80 ° C. and reacted for 2 hours to obtain an isocyanate group-terminated urethane prepolymer (first-stage reaction). Next, the content liquid was cooled to 60 ° C., 20 parts by mass of the active hydrogen group-containing compound (HB-2) was added, mixed and reacted (second stage reaction).
In the entire first and second stage reactions, the active hydrogen groups (H) possessed by all the active hydrogen group-containing compounds (HX) (in this example, (HA-1) and (HB-2)) used in the reaction. The ratio (NCO / H) of the number of moles of the isocyanate group (NCO) of the polyisocyanate (N) used in the reaction to the total number of moles of) was 0.62.
After confirming the disappearance of the residual isocyanate group by infrared spectroscopic analysis (IR analysis), the content liquid was cooled to terminate the reaction, and then 1 part by mass of the antioxidant (D-1) and the β-diketone compound (X). -1) 3 parts by mass was added and mixed.
As described above, a colorless and transparent hydroxyl-terminated urethane prepolymer (UPH-1) -containing solution was obtained.
The main manufacturing conditions and evaluation results are shown in Table 1-1 and Table 2-1.
Tables 1-1 to 1-7 show the raw material compositions of the urethane prepolymer alone or the polyol mixture alone, NCO / H, and Mn and Mw of the urethane prepolymer.
Tables 2-1 to 2-2 show the composition of the urethane prepolymer-containing solution or the polyol-containing solution, the solid content concentration, and the viscosity at 25 ° C. after standing at 25 ° C. for 1 hour immediately after the preparation.
The unit of the compounding amount in the table is "part by mass" (the same applies to other tables).

(Production Examples 2 to 40, 42 to 45) (Two-stage polymerization method)
Hydroxyl-terminated urethane prepolymers (UPH-2) to (UPH-45) -containing solutions were obtained by a two-stage polymerization method in the same manner as in Production Example 1 except that the type of raw material used and the compounding ratio were changed.
100 parts by mass of one or more polyols (HA) or one or more polyols (HL) in a four-necked flask equipped with a stirrer, a reflux condenser, a nitrogen introduction tube, a thermometer, and a dropping funnel. Polyisocyanate (N), an organic solvent (B) and / or a plasticizer (P) as a diluent, and 0.01 part by mass of dioctyltin dilaurate as a catalyst were charged and mixed. The content was gradually heated to 80 ° C. and reacted for 2 hours to obtain an isocyanate group-terminated urethane prepolymer (first-stage reaction). Next, the content liquid was cooled to 60 ° C., one or more active hydrogen group-containing compounds (HB) were added, mixed and reacted (second stage reaction).
After confirming the disappearance of the residual isocyanate group by infrared spectroscopic analysis (IR analysis), the content liquid is cooled to terminate the reaction, and then the antioxidant (D-1) and the β-diketone compound (X-1) are used. And, optionally, an AS agent (F-1) was added and mixed. As described above, colorless and transparent hydroxyl-terminated urethane prepolymers (UPH-2) to (UPH-32) and (UPH-34) (UPH-37) -containing solutions were obtained.
The main manufacturing conditions and evaluation results are shown in Tables 1-1 to 1-6 and Tables 2-1 to 2-2.

(Production Example 41) (Two-stage polymerization method)
A hydroxyl-terminated urethane prepolymer (UPH-33) -containing solution was obtained by a two-stage polymerization method in the same manner as in Production Example 1 except that the type of raw material used and the compounding ratio were changed.
In a 4-neck flask equipped with a stirrer, a reflux condenser, a nitrogen introduction tube, a thermometer, and a dropping funnel, 100 parts by mass of polyol (HB-6), 80 parts by mass of polyisocyanate (N-1), as a diluent. 10 parts by mass of the organic solvent (B-1), 100 parts by mass of the plasticizer (P-1), and 0.01 parts by mass of dioctyltin dilaurate as a catalyst were charged and mixed. The content was gradually heated to 80 ° C. and reacted for 2 hours to obtain an isocyanate group-terminated urethane prepolymer (first-stage reaction). Next, the content liquid was cooled to 60 ° C., an active hydrogen group-containing compound (HB-2) was added, mixed and reacted (second-stage reaction).
After confirming the disappearance of the residual isocyanate group by infrared spectroscopic analysis (IR analysis), the content liquid is cooled to terminate the reaction, and then the antioxidant (D-1) and the β-diketone compound (X-1) are used. And were added and mixed. As described above, a colorless and transparent hydroxyl-terminated urethane prepolymer (UPH-41) -containing solution was obtained.
The main manufacturing conditions and evaluation results are shown in Tables 1-6 and 2-2.

(Production Example 46) (One-stage polymerization method)
100 parts by mass of polyol (HA-6), 8 parts by mass of active hydrogen group-containing compound (HB-2), in a 4-neck flask equipped with a stirrer, a reflux condenser, a nitrogen introduction tube, a thermometer, and a dropping funnel. Add 10 parts by mass of organic solvent (B-1) and 100 parts by mass of plasticizer (P-1) as a diluent, and 0.01 part by mass of dioctyltin dilaurate as a catalyst and mix them, and gradually raise the content to 80 ° C. It was warm. Then, 13 parts by mass of polyisocyanate (N-1) was added and reacted for 2 hours. After confirming the disappearance of the residual isocyanate group by infrared spectroscopic analysis (IR analysis), the content liquid was cooled to terminate the reaction, and then 1 part by mass of the antioxidant (D-1) and the β-diketone compound (X). -1) 3 parts by mass was added and mixed. As described above, a colorless and transparent hydroxyl-terminated urethane prepolymer (UPH-38) -containing solution was obtained.
The main manufacturing conditions and evaluation results are shown in Tables 1-6 and 2-2.

(Production Examples 47, 48) (One-stage polymerization method)
30 parts by mass of polyol (HA-1), 70 parts by mass of polyol (HA-7), and polyisocyanate (N) in a 4-neck flask equipped with a stirrer, a reflux condenser, a nitrogen introduction tube, a thermometer, and a dropping funnel. -2) Add 5 parts by mass, 90 parts by mass or 30 parts by mass of the organic solvent (B-1) as a diluent, 40 parts by mass of a plastic agent (P-1), and 0.01 parts by mass of dioctyltin dilaurate as a catalyst. Mixed. The content was gradually heated to 80 ° C. and reacted for 2 hours.
After confirming the disappearance of the residual isocyanate group by infrared spectroscopic analysis (IR analysis), the content liquid was cooled to terminate the reaction, and then 1 part by mass of the antioxidant (D-1) and the β-diketone compound (X). -1) 3 parts by mass was added and mixed. As described above, a colorless and transparent solution containing a hydroxyl-terminated urethane prepolymer (UPH-39) for comparison was obtained.
The main manufacturing conditions and evaluation results are shown in Table 1-7 and Table 2-2.

(Production Example 49) (One-stage polymerization method)
100 parts by mass of polyol (HA-6), 5 parts by mass of active hydrogen group-containing compound (HB-2), in a 4-neck flask equipped with a stirrer, a reflux cooling tube, a nitrogen introduction tube, a thermometer, and a dropping funnel. 40 parts by mass of polyisocyanate (N-1), 10 parts by mass of organic solvent (B-1) and 100 parts by mass of plasticizer (P-1) as a diluent, and 0.01 parts by mass of dioctyltin dilaurate as a catalyst were charged. Mixed. The content was gradually heated to 80 ° C. and reacted for 2 hours.
After cooling the content liquid to complete the reaction, 1 part by mass of the antioxidant (D-1) and 3 parts by mass of the β-diketone compound (X-1) were added and mixed. As described above, a colorless and transparent isocyanate group-terminated urethane prepolymer (UPN-1) -containing solution for comparison was obtained.
The main manufacturing conditions and evaluation results are shown in Table 1-7 and Table 2-2.

(Manufacturing Example 50)
100 parts by mass of polyol (HA-6), 5 parts by mass of active hydrogen group-containing compound (HB-2), 10 parts by mass of organic solvent (B-1) and 100 parts by mass of plasticizer (P-1) as diluent, catalyst By mixing 0.01 part by mass of dioctyl tin dilaurate, 1 part by mass of antioxidant (D-1), and 3 parts by mass of β-diketone compound (X-1), a colorless and transparent comparative polyol (PO- 1) A containing solution was obtained.
The main manufacturing conditions and evaluation results are shown in Table 1-7 and Table 2-2.

[Manufacturing urethane adhesives and adhesive sheets]
(Examples 1 to 54, Comparative Examples 1 to 4)
By blending the urethane prepolymer-containing solution or the polyol-containing solution obtained in any of the above production examples, the polyfunctional isocyanate compound (I), and optionally the organic solvent (B), and stirring with a disper. , Urethane-based adhesive was obtained.
The obtained pressure-sensitive adhesive was evaluated for solid content concentration, viscosity immediately after preparation and after standing at 25 ° C. for 3 hours, and pot life.
A 50 μm-thick polyethylene terephthalate (PET) film (Lumirror T-60, manufactured by Toray Industries, Inc.) was prepared as a base sheet. Using a comma coater (registered trademark), a urethane adhesive that had been allowed to stand at 25 ° C. for 3 hours or less immediately after preparation was applied to one side of this base material sheet so that the thickness after drying would be 12 μm. Then, the formed coating layer was dried at 100 ° C. for 2 minutes to form an adhesive layer. A release sheet having a thickness of 38 μm (Super Stick SP-PET38, manufactured by Lintec Corporation) was attached onto this adhesive layer to obtain an adhesive sheet. After curing for a predetermined time under the condition of 23 ° C.-50% RH, initial curability, wettability, and removability were evaluated. In addition, Comparative Example 4 is an example in which the pressure-sensitive adhesive was produced by the one-shot method.
The composition of the pressure-sensitive adhesive and the evaluation results of the pressure-sensitive adhesive and the pressure-sensitive adhesive sheet are shown in Tables 3-1 to 3-2 and Tables 4-1 to 4-2.

[Evaluation results]
Production Examples 1 to 46 contain a hydroxyl-terminated urethane prepolymer (UPH), which is a reaction product of one or more active hydrogen group-containing compounds (HX) and one or more polyisocyanates (N), and have a solid content concentration. A hydroxyl-terminated urethane prepolymer-containing solution having a viscosity of 80% by mass or more and a viscosity at 25 ° C. of 8000 mPa · s or less after being allowed to stand at 25 ° C. for 1 hour immediately after preparation could be prepared. In each of these production examples, the amount of the organic solvent used was reduced, and a hydroxyl-terminated urethane prepolymer-containing solution having a relatively high solid content concentration and a relatively low viscosity could be synthesized.

In Examples 1 to 54, the hydroxyl-terminated urethane prepolymer-containing solution obtained in any of Production Examples 1 to 46 and the polyfunctional isocyanate compound (I) are contained, and the solid content concentration is 70% by mass or more or 80. It was possible to prepare a pressure-sensitive adhesive having a mass% or more and a viscosity at 25 ° C. of 9000 mPa · s or less or 5000 mPa · s or less after being allowed to stand at 25 ° C. for 3 hours immediately after preparation. In these examples, a pressure-sensitive adhesive sheet was produced using a pressure-sensitive adhesive that was allowed to stand at 25 ° C. for up to 3 hours immediately after preparation. In all the examples, the coatability of the pressure-sensitive adhesive was good.
In each of Examples 1 to 54, a pressure-sensitive adhesive having a relatively low viscosity at the time of coating is produced so that the amount of the organic solvent used is reduced, the solid content concentration is relatively high, and the coating suitability is good. We were able to. In each of these examples, a pressure-sensitive adhesive having a good pot life could be produced, and a pressure-sensitive adhesive sheet having good initial curability, wettability, and removability could be produced.

The hydroxyl-terminated urethane prepolymer-containing solution obtained in Production Example 47 had a low solid content concentration, and the pressure-sensitive adhesive of Comparative Example 1 using this had a low solid content concentration and had a poor VOC reduction effect.
The hydroxyl-terminated urethane prepolymer-containing solution obtained in Production Example 48 had a high viscosity, and the pressure-sensitive adhesive of Comparative Example 2 using the solution had a high viscosity, poor pot life, and poor coatability.
The pressure-sensitive adhesive of Comparative Example 3 using the isocyanate group-terminated urethane prepolymer-containing solution obtained in Production Example 49 had a poor pot life, and the pressure-sensitive adhesive sheet using this had a poor initial curability.
In Production Example 50, a polyol-containing solution was obtained, and in Comparative Example 4, a pressure-sensitive adhesive was produced by a one-shot method using this solution. The adhesive sheet using this had poor initial curability.

The present invention is not limited to the above embodiments and examples, and the design can be appropriately changed as long as the gist of the present invention is not deviated.

This application claims priority based on Japanese Application Japanese Patent Application No. 2019-091953 filed on May 15, 2019, and incorporates all of its disclosures herein.

10, 20

Adhesive sheet

11, 21

Base sheet

12, 22A,

22B Adhesive layer

13, 23A, 23B Release sheet

Claims

It contains a hydroxyl-terminated urethane prepolymer (UPH) which is a reaction product of one or more active hydrogen group-containing compounds (HX) having a plurality of active hydrogen groups in one molecule and one or more polyisocyanates (N). ,
A hydroxyl-terminated urethane prepolymer-containing solution for an adhesive, which has a solid content concentration of 80% by mass or more and a viscosity at 25 ° C. of 8000 mPa · s or less after being allowed to stand at 25 ° C. for 1 hour immediately after preparation.
One or more active hydrogen group-containing compounds (HX) include one or more polyols (HA) having a number average molecular weight of 1000 or more and a plurality of active hydrogen groups in one molecule having a number average molecular weight of less than 1000. The hydroxyl group-terminated urethane prepolymer-containing solution according to claim 1, which comprises one or more active hydrogen group-containing compounds (HB) having.
The hydroxyl-terminated urethane prepolymer-containing solution according to claim 1 or 2, wherein one or more polyols (HA) contain a trifunctional or higher functional polyether polyol.
The ratio of the number of moles of isocyanate group (NCO) of one or more polyisocyanates (N) to the total number of moles of active hydrogen groups (H) of one or more active hydrogen group-containing compounds (HX) (NCO / H) ) Is 0.20 to 0.84, the hydroxyl group-terminated urethane prepolymer-containing solution according to any one of claims 1 to 3.
The hydroxyl group-terminated urethane prepolymer (UPH) is a reaction product of an isocyanate group-terminated urethane prepolymer (UPN), which is a reaction product of a polyol (HA) and a polyisocyanate (N), and an active hydrogen group-containing compound (HB). The hydroxyl group-terminated urethane prepolymer-containing solution according to any one of claims 1 to 4, which is a compound.
The hydroxyl-terminated urethane prepolymer-containing solution according to any one of claims 1 to 5, wherein one or more polyisocyanates (N) contain isophorone diisocyanate.
The hydroxyl group-terminated urethane prepolymer-containing solution according to any one of claims 1 to 6, wherein the active hydrogen group-containing compound (HB) contains a primary hydroxyl group.
A pressure-sensitive adhesive containing the hydroxyl-terminated urethane prepolymer-containing solution according to any one of claims 1 to 7 and the polyfunctional isocyanate compound (I).
The pressure-sensitive adhesive according to claim 8, wherein the solid content concentration is 80% by mass or more, and the viscosity at 25 ° C. after standing at 25 ° C. for 3 hours immediately after preparation is 5000 mPa · s or less.
The pressure-sensitive adhesive according to claim 8 or 9, further comprising a plasticizer.
The pressure-sensitive adhesive according to any one of claims 8 to 10, further comprising a β-diketone compound.
The adhesive according to any one of claims 8 to 11, further comprising an antistatic agent.
The adhesion according to any one of claims 8 to 12, further comprising one or more antioxidants selected from the group consisting of antioxidants, hydrolysis resistant agents, UV absorbers, and light stabilizers. Agent.
An adhesive sheet containing a base material sheet and an adhesive layer made of a cured product of the adhesive according to any one of claims 8 to 13.
One or more polyols (HA) having a number average molecular weight of 1000 or more and one or more polyisocyanates (N) are reacted at an excess ratio of isocyanate groups to produce an isocyanate group-terminated urethane prepolymer (UPN). Process and
A step of reacting the obtained isocyanate group-terminated urethane prepolymer (UPN) with one or more active hydrogen group-containing compounds (HB) having a plurality of active hydrogen groups in one molecule having a number average molecular weight of less than 1000. Have,
The method for producing a hydroxyl-terminated urethane prepolymer-containing solution according to claim 2.
A step of mixing at least the hydroxyl-terminated urethane prepolymer-containing solution and the polyfunctional isocyanate compound (I) to prepare a pressure-sensitive adhesive having a solid content concentration of 80% by mass or more.
A step of coating the pressure-sensitive adhesive on the base material sheet to form a coating layer, and
It has a step of drying the coating layer.
The method for producing an adhesive sheet according to claim 14, wherein the pressure-sensitive adhesive at the time of coating has a viscosity of 5000 mPa · s or less at 25 ° C.