JP2010100835A - Adherence substance and adhesive sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adherence substance with excellent endurance, having a low viscosity as a composition before curing for providing a preferable coating property for enabling elimination of a solvent, a low adhesion force after curing with a small rise of adhesion force by passage of time for providing a preferable cohesiveness to a substrate, excellent cohesiveness to an adherend and re-detachability, and a preferable wettability. <P>SOLUTION: The adherence substance is obtained by curing a curable composition including: a silyl group-containing polymer (S) having a polyether chain, a polyester chain, and/or a polycarbonate chain in the main chain and a hydrolyzable silyl group at a molecular terminal; and an acrylic polymer (P). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

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

  The adhesive is required to adhere to the adherend and not easily peel off. On the other hand, the pressure-sensitive adhesive is molded into a shape such as a tape and is required to exhibit good adhesiveness immediately after being bonded. At the same time, the pressure-sensitive adhesive is required to have removability so that it can be peeled off so that there is no adhesive residue. In contrast to the adhesive requiring permanent adhesion, the pressure-sensitive adhesive is required to have both temporary adhesion and removability. Therefore, although the adhesive and the pressure-sensitive adhesive are similar, the required characteristics are fundamentally different.

As conventional adhesives, acrylic adhesives, rubber adhesives, silicone adhesives, urethane adhesives, and oxyalkylene adhesives are known. Particularly recently, acrylic adhesives tend to be used for a wide range of applications from strong adhesives having strong adhesive strength to fine adhesive adhesives having minute adhesive strength. However, the acrylic pressure-sensitive adhesive tends to increase in adhesive force or transferability due to a change with time after being attached to an adherend. For this reason, there is a problem that adhesive residue tends to be generated on the adherend and re-peelability tends to be insufficient.
For rubber adhesives, the addition of a low molecular weight plasticizer is indispensable for adjusting the handleability and adhesive performance. Therefore, when a long period of time elapses, there is a problem that the low molecular weight plasticizer moves to the surface and causes a significant performance degradation.
Silicone adhesives are excellent in heat resistance. However, it is expensive and has been deployed only for special purposes.

A urethane-based pressure-sensitive adhesive has a characteristic that there is little change with time and excellent stability (see Patent Document 1). However, the manufacturing process tends to be long, and tends to be expensive compared to acrylic adhesives. In addition, since the manufacturing process is long, there is a problem in that variations in quality are likely to occur and process management tends to be complicated.
The oxyalkylene-based pressure-sensitive adhesive has a characteristic that it can be applied without using an organic solvent (see Patent Documents 2 and 3). However, bleeding of the tackifier resin may occur, and there is a problem in terms of long-term adhesion stability.

  In recent years, when manufacturing electrical parts, electronic materials, and the like, protective sheets and protective tapes are frequently used. This is to protect these parts and materials from scratches and dust in processes such as storage and transportation. Particularly in the manufacture of electronic parts and optical members, it is necessary to thoroughly eliminate the attachment of minute dust to products being manufactured. This is because dust causes contamination and causes product defects. As the protective sheet or the protective tape, an adhesive sheet or an adhesive tape provided with an adhesive layer having a low adhesive force is employed.

JP 2003-12751 A International Publication No. 2005/73333 Pamphlet International Publication No. 2005/73334 Pamphlet

  Conventional pressure-sensitive adhesives such as acrylics have problems that adhesion to a substrate and wettability are poor, and adhesive strength tends to increase with time. Especially when trying to produce an adhesive with low adhesive strength, even if the composition of the adhesive is adjusted so that the initial adhesive strength is low, there is a problem that the adhesive strength increases if the sticking time becomes long. there were. If the adhesive force is increased, the adherend may be deformed or damaged. On the other hand, when the composition of the pressure-sensitive adhesive is adjusted so that the pressure-sensitive adhesive strength is lowered after a certain time, there is a problem that sufficient pressure-sensitive adhesive strength cannot be obtained in the first place. If sufficient adhesive strength is not obtained, it will peel off unintentionally from the adherend, and it will not be able to play a predetermined role such as a protective sheet. In addition, the thickness of the pressure-sensitive adhesive layer may be reduced to suppress an increase in adhesive force. However, in this case, it is difficult to reduce the holding force and increase the thickness accuracy.

  When a resin, which is a raw material for the urethane-based pressure-sensitive adhesive described in Patent Document 1, is produced, a polymer having a predetermined structure is obtained using a slight difference in reactivity of the raw materials. However, the control of the structure by the difference in reactivity requires precise control of reaction conditions. As a result, in the production of this resin, it was difficult to control the molecular weight, and it was difficult to obtain a pressure-sensitive adhesive having a desired performance. In particular, it was difficult to control the generation of a high molecular weight body and the progress of gelation associated therewith. The molecular weight is related to the cohesive force of the molecules and has an influence on the tackiness and re-peeling properties. Moreover, when gelatinization advances extremely, the composition obtained will be easy to become high viscosity. When the composition has a high viscosity, it may be difficult to obtain a pressure-sensitive adhesive layer having a predetermined thickness uniformly during molding of the pressure-sensitive adhesive, or the surface of the obtained pressure-sensitive adhesive may not be smooth. There was a manufacturing problem. Even if the apparent viscosity is lowered by using a solvent, problems such as difficulty in obtaining a thick adhesive, easy foaming, and a long drying time occur.

  The present invention has been made in view of the above problems, and the composition before curing has a low viscosity and good coatability, can be made solvent-free, has low adhesive strength after curing, and has low adhesive strength. To provide a pressure-sensitive adhesive having excellent durability, having a small increase over time, good adhesion to a substrate, excellent adhesion to an adherend and removability, and good wettability. With the goal.

The present invention has the following aspects.
[1] A silyl group-containing polymer (S) having a polyether chain, a polyester chain, and / or a polycarbonate chain as a main chain and a hydrolyzable silyl group at a molecular end, and an acrylic polymer (P) A pressure-sensitive adhesive obtained by curing a curable composition.
[2] The hydrolyzable silyl group at the end of one or more polyol compounds selected from the group consisting of the polyether polyol, polyester polyol, polycarbonate polyol, and polyether polyester polyol is used as the silyl group-containing polymer (S). [1] The pressure-sensitive adhesive according to [1], which is a silyl group-containing polymer (S1) obtained by introducing.
[3] The silyl group-containing polymer (S) is reacted with at least one polyol compound selected from the group consisting of polyether polyol, polyester polyol, polycarbonate polyol, and polyether polyester polyol and a polyisocyanate compound. [1] The pressure-sensitive adhesive according to [1], which is a silyl group-containing polymer (S2) obtained by introducing a hydrolyzable silyl group into the terminal of the polyurethane prepolymer obtained.
[4] The silyl group-containing polymer (S) reacts a polyisocyanate compound with at least one polyol compound selected from the group consisting of polyether polyol, polyester polyol, polycarbonate polyol, and polyether polyester polyol. This is a silyl group-containing polymer (S3) obtained by introducing a hydrolyzable silyl group into the molecular terminal of a polyurethane polymer obtained by further subjecting the polyurethane prepolymer obtained by chain extension reaction using a chain extender. The adhesive body according to [1].

[5] The pressure-sensitive adhesive body according to any one of [1] to [4], wherein the acrylic polymer (P) has a number average molecular weight of 10,000 to 1,000,000.
[6] The hydrolyzable silyl group of the silyl group-containing polymer (S) uses one or more silane compounds selected from isocyanate silanes, aminosilanes, mercaptosilanes, epoxysilanes, and hydrosilanes. The pressure-sensitive adhesive body according to any one of [1] to [5],
[7] The pressure-sensitive adhesive according to any one of [1] to [6], wherein the hydrolyzable silyl group is a trialkoxysilyl group.
[8] The pressure-sensitive adhesive body according to any one of [1] to [7], wherein the peel adhesive strength is 8 N / 25 mm or less.
[9] A pressure-sensitive adhesive sheet having a base material layer and at least one pressure-sensitive adhesive layer, wherein the pressure-sensitive adhesive layer comprises the pressure-sensitive adhesive according to any one of [1] to [8]. Adhesive sheet.

  According to the present invention, the composition before curing has a low viscosity, good coatability, can be made solvent-free, has low adhesive strength after curing, and has a small increase in adhesive strength with time. A pressure-sensitive adhesive body excellent in durability, having good adhesion, excellent adhesion to an adherend and removability, and good wettability is obtained.

The molecular weight distribution in this specification refers to a value obtained by dividing the mass average molecular weight (Mw) by the number average molecular weight (Mn). The number average molecular weight (Mn), mass average molecular weight (Mw) and molecular weight distribution (Mw / Mn) in this specification are measured by gel permeation chromatography using a calibration curve prepared using a standard polystyrene sample with a known molecular weight. This is the molecular weight in terms of polystyrene obtained by
The average hydroxyl value (OHV) in this specification is a measured value based on JIS-K-1557-6.4.

In the present specification, the adhesion property is a property that adheres to an adherend with light pressure and can be re-peeled arbitrarily. An adhesive (pressure sensitive adhesive) is a substance that has adhesiveness and adheres to an adherend with light pressure. It has removability and is used for temporary adhesion. On the other hand, the adhesive is different from the pressure-sensitive adhesive in that it has a permanent adhesive performance.
An adhesive substance is an adhesive compact. An adhesive sheet (also simply referred to as an adhesive sheet) (pressure sensitive adhesive sheet) is an adhesive sheet. However, in this specification, the thickness and the sheet are not distinguished from each other. The pressure-sensitive adhesive sheet is usually a laminate having at least a base material layer and a pressure-sensitive adhesive layer as components. An adhesive tape (also simply referred to as an adhesive tape) is a tape-shaped adhesive sheet.

In the present specification, pressure-sensitive adhesives may be classified according to peel adhesive strength (peel strength from the adherend). Slight adhesion when peel adhesion exceeds 0 N / 25 mm and less than 1 N / 25 mm, low adhesion when peel adhesion exceeds 1 N / 25 mm and less than 8 N / 25 mm, peel adhesion exceeds 8 N / 25 mm and 15 N / 25 mm The following cases are referred to as medium adhesion, and the case where the peel adhesive strength exceeds 15 N / 25 mm and is 50 N / 25 mm or less is called strong adhesion. Unless otherwise specified, the peel adhesive strength conforms to the 180-degree peeling method specified in JIS-Z-0237 (1999) -8.3.1 and follows the following test method.
That is, in a 23 ° C. environment, a 1.5 mm thick bright annealed stainless steel plate (SUS304 (JIS)) was attached to a pressure sensitive adhesive sheet test piece (width: 25 mm), and a rubber roll having a mass of 2 kg. Crimp. After 30 minutes, the peel strength (180 degree peel, tensile speed 300 mm / min) is measured using a tensile tester specified in JIS-B-7721. The value of the peel strength after 30 minutes of sticking obtained in this way is defined as “peel adhesive strength” in the present invention.

<Silyl group-containing polymer (S)>
The pressure-sensitive adhesive body of the present invention is obtained by curing a curable composition containing a silyl group-containing polymer (S) and an acrylic polymer (P). The silyl group-containing polymer (S) has a polyether chain, a polyester chain, and / or a polycarbonate chain in the main chain and a hydrolyzable silyl group at the molecular end.
The silyl group-containing polymer (S) is preferably used in the form of any one of the following (S1) to (S3), or a mixture of two or more. Among these, (S1) is preferable from the viewpoint that the obtained cured product is excellent in flexibility and wettability.

<Silyl group-containing polymer (S1)>
The silyl group-containing polymer (S1) is obtained by introducing a hydrolyzable silyl group into the terminal of one or more polyol compounds selected from the group consisting of polyether polyol, polyester polyol, polycarbonate polyol, and polyether polyester polyol. can get.
The polyether polyol in the present invention is a polyol having a polyether chain (—OR ¹ —) _n1 [R ¹ is an alkylene group having 2 to 4 carbon atoms, n1 is an integer of 1 to 1000], and has a polyester chain. Absent.
The polyester polyol is a polyol having a polyester chain (—OC (O) —R ² —) _n2 [R ² is an alkylene group or arylene group having 2 to 8 carbon atoms, and n 2 is an integer of 1 to 1000], and is a polyether. Has no chains.
The polycarbonate polyol is a polyol having a polycarbonate chain (—OC (O) —O—R ³ —) _n3 [R ³ is an alkylene group or arylene group having 2 to 20 carbon atoms, and n3 is an integer of 1 to 1000] It has neither a polyether chain nor a polyester chain.
The polyether polyester polyol is a polyol having both a polyether chain and a polyester chain.
The silyl group-containing polymer (S1) is particularly preferably obtained by introducing a hydrolyzable silyl group into the polyol compound by the method described in any of (PQ1) to (PQ5) described later.

<Silyl group-containing polymer (S2)>
The silyl group-containing polymer (S2) is a polyurethane obtained by reacting at least one polyol compound selected from the group consisting of polyether polyol, polyester polyol, polycarbonate polyol, and polyether polyester polyol with a polyisocyanate compound. It is obtained by introducing a hydrolyzable silyl group at the end of the prepolymer.
The silyl group-containing polymer (S2) is particularly preferably obtained by introducing a hydrolyzable silyl group into a polyurethane prepolymer by the method described in any of (PQ1) to (PQ5) described later.

<Silyl group-containing polymer (S3)>
The silyl group-containing polymer (S3) is a polyurethane obtained by reacting one or more polyol compounds selected from the group consisting of polyether polyol, polyester polyol, polycarbonate polyol, and polyether polyester polyol with a polyisocyanate compound. This is obtained by introducing a hydrolyzable silyl group into the molecular terminal of a polyurethane polymer obtained by subjecting the prepolymer to a chain extension reaction using a chain extender.
The silyl group-containing polymer (S3) is particularly preferably obtained by introducing a hydrolyzable silyl group into a polyurethane polymer by the method described in any of (PQ1) to (PQ5) described later.

<Polyol compound>
As the polyol compound according to the present invention, polyether polyol, polyester polyol, polycarbonate polyol, polyether polyester polyol can be used. As a polyol compound, only 1 type of these polyols may be used, or 2 or more types may be used together. In particular, it is preferable to use at least one polyol having a polyether skeleton (polyether chain) from the viewpoint of securing the flexibility of the pressure-sensitive adhesive. The fact that the pressure-sensitive adhesive body is flexible is considered to be effective for suppressing so-called zipping, a phenomenon in which a sound of crispness is generated without peeling off smoothly when peeling off the pressure-sensitive adhesive body from the adherend. Moreover, the viscosity of a curable composition can be made low by having a polyether skeleton. Further, it is presumed that by having a polyether skeleton, the surface resistance of the pressure-sensitive adhesive body can be lowered, and peeling charge can be suppressed.
The ratio of the ether bond (—OR ¹ —) in the silyl group-containing polymer (S) is 40% with respect to the total (100 mol%) of the ether bond and the ester bond (—OC (O) —R ² —). -100 mol% is preferable, 50-100 mol% is more preferable, and 60-100 mol% is further more preferable.

The polyol having a polyether skeleton means a polyol having a polyether chain, such as a polyether polyol and a polyether polyester polyol.
In the present invention, as the polyol compound for obtaining the silyl group-containing polymer (S), one or more polyols selected from polyether polyols and polyether polyester polyols are used, or polyether polyols and polyether polyesters are used. It is preferable to use one or more polyols selected from polyols in combination with one or more polyols selected from polyester polyols and polycarbonate polyols. More preferably, polyether polyol or polyether polyester polyol is used.

As the polyether polyol, polyoxyalkylene polyol is preferable.
Examples of the alkylene group constituting the polyoxyalkylene polyol include an ethylene group, trimethylene group, tetramethylene group, pentamethylene group, hexamethylene group, propylene group, butylene group, and methyltrimethylene group. These can be obtained by ring-opening polymerization of a corresponding cyclic ether compound or epoxide compound. Examples of cyclic ether compounds include tetrahydrofuran and oxetane. Examples of the epoxide compound include ethylene oxide, propylene oxide, butylene oxide, and the like. Suitable examples of the polyether polyol include polyoxytetramethylene polyol, polyoxyethylene polyol, polyoxypropylene polyol, and polyoxyethylene polyoxypropylene polyol.

  Examples of the polyether polyester polyol include polyols obtained by condensation polymerization of ether diols and dibasic acid compounds, polyols obtained by ring-opening copolymerization (particularly random copolymerization) of epoxide compounds and cyclic esters, and the like. Can be illustrated. Examples of ether diols include diethylene glycol, dipropylene glycol, polyoxyethylene glycol, polyoxypropylene glycol, and polyoxyethylene polyoxypropylene glycol. Examples of the dibasic acid compound include phthalic acid, maleic acid, adipic acid, and fumaric acid. Examples of cyclic esters (lactones) include β-propiolactone (carbon number 3), δ-valerolactone (carbon number 5), and ε-caprolactone (carbon number 6). Of these, ε-caprolactone is more preferred. The epoxide compound is as described above.

Examples of the polyester polyol include polyols obtained by condensation polymerization of low molecular diols such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, and the aforementioned dibasic acid compound.
As said polycarbonate polyol, what is obtained by making the low molecular carbonate compound which consists of alkylene carbonate, dialkyl carbonate, and diaryl carbonate react with a diol compound is preferable. Specific examples include polyhexamethylene carbonate diol, poly (3-methylpentene carbonate) diol, and polypropylene carbonate diol. Moreover, those mixtures or those copolymers may be sufficient.

In the present invention, the number of hydroxyl groups in the polyol compound for obtaining the silyl group-containing polymer (S) is preferably 2 to 3, and most preferably 2. That is, it is particularly preferable to use a diol as the polyol compound. If the number of hydroxyl groups is in this range, it is preferable because the viscosity of the resulting polyurethane prepolymer can be easily kept low.
The average hydroxyl value of the polyol compound is preferably 5 to 225 mgKOH / g, more preferably 7 to 115 mgKOH / g, and particularly preferably 10 to 112 mgKOH / g. If the average hydroxyl value is within this range, it is preferable because the viscosity of the resulting silyl group-containing polymer (S) can be easily kept low.
In particular, when the silyl group-containing polymer (S1) is obtained, the average hydroxyl value of the polyol compound is preferably 5 to 112 mgKOH / g, more preferably 7 to 56 mgKOH / g. Furthermore, 7-28 mgKOH / g is especially preferable. The average hydroxyl value of the polyol compound when obtaining the silyl group-containing polymer (S2) or (S3) is preferably 25 to 225 mgKOH / g, more preferably 30 to 115 mgKOH / g.

<Polyisocyanate compound>
In order to obtain the silyl group-containing polymer (S2) or (S3), a polyurethane prepolymer is used. As the polyisocyanate compound used for the synthesis of the polyurethane prepolymer, known compounds can be used. Specific examples include diisocyanate compounds such as diphenylmethane diisocyanate, tolylene diisocyanate, xylylene diisocyanate, methylene-bis (cyclohexyl isocyanate), isophorone diisocyanate and hexamethylene diisocyanate. These may use only 1 type or may use 2 or more types together. A polyisocyanate compound having a bent chain is preferable because flexibility of the obtained pressure-sensitive adhesive body is improved. Specific examples include tolylene diisocyanate, m-xylylene diisocyanate, and isophorone diisocyanate. Of these, tolylene diisocyanate or isophorone diisocyanate is particularly preferred.

<Polyurethane prepolymer>
The polyurethane prepolymer for obtaining the silyl group-containing polymer (S2) or (S3) is obtained by reacting the polyol compound with a polyisocyanate compound. The terminal of the polyurethane prepolymer is an isocyanate group or a hydroxyl group, and is appropriately selected depending on the method for introducing a hydrolyzable silyl group. That is, it may be an isocyanate group-terminated polyurethane prepolymer or a hydroxyl group-terminated polyurethane prepolymer.
In synthesizing the polyurethane prepolymer, the ratio of reacting the polyol compound with the polyisocyanate compound is appropriately selected depending on the molecular weight (average hydroxyl value) of the polyol compound and the molecular weight of the target polyurethane prepolymer. When an isocyanate group-terminated polyurethane prepolymer is obtained, the ratio of the polyol compound to be reacted and the polyisocyanate compound is defined as a value 100 times the molar ratio of “NCO group of polyisocyanate compound / OH group of polyol compound”. The isocyanate index is preferably more than 100 to 200, more preferably 105 to 170. When obtaining a hydroxyl group-terminated polyurethane prepolymer, the ratio of the polyol compound to be reacted and the polyisocyanate compound is preferably 50 to less than 100 and more preferably 50 to 98 in terms of isocyanate index.
The molecular weight of the polyurethane prepolymer is preferably 2,000 to 100,000 in terms of number average molecular weight. More preferably, it is 3,000-80,000.

  The polyurethane polymer for obtaining the silyl group-containing polymer (S3) is obtained by subjecting a polyurethane prepolymer to a chain extension reaction using a chain extender. The polyurethane prepolymer is the same as in the case of the silyl group-containing polymer (S2).

<Chain extender>
As the chain extender, when an isocyanate group-terminated polyurethane prepolymer is used as the polyurethane prepolymer, low molecular diols and low molecular diamines are preferable. Preferred examples of the low molecular diols include ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, and the like. Low molecular diamines include aliphatic diamines such as ethylene diamine, propylene diamine, trimethylene diamine, tetramethylene diamine, pentamethylene diamine, hexamethylene diamine, and 2,2,4-trimethylhexamethylene diamine; piperazine, isophorone diamine, dicyclohexyl And alicyclic diamines such as methane-4,4′-diamine; and aromatic diamines such as tolylenediamine, phenylenediamine, and xylylenediamine.
When a hydroxyl-terminated polyurethane prepolymer is used as the polyurethane prepolymer, a diisocyanate compound is preferred as the chain extender. The diisocyanate compound is the same as that used for the polyurethane prepolymer.

<Polyurethane resin>
The polyurethane resin according to the present invention is obtained by subjecting the polyurethane prepolymer to a chain extension reaction. The terminal of the polyurethane resin is an isocyanate group, a hydroxyl group, or an amino group, and is appropriately selected depending on the method for introducing a hydrolyzable silyl group. That is, it may be an isocyanate group-terminated polyurethane resin, a hydroxyl group-terminated polyurethane resin, or an amino group-terminated polyurethane resin.
In synthesizing the polyurethane resin, the ratio of reacting the polyurethane prepolymer with the chain extender is appropriately selected depending on the molecular weight of the polyurethane prepolymer and the molecular weight of the target polyurethane resin.

When the isocyanate group-terminated polyurethane prepolymer is chain extended using a low molecular diol as a chain extender, the ratio of the polyurethane prepolymer to the low molecular diol is expressed as "NCO group of polyurethane prepolymer / OH of low molecular diols". The isocyanate index defined by a value 100 times the molar ratio of “group” is preferably more than 100 to 200, more preferably more than 100 to 150. Within this range, an isocyanate group-terminated polyurethane resin can be obtained.
Moreover, when obtaining a hydroxyl-terminated polyurethane resin, it is preferable that this isocyanate index is less than 50-100, and 50-98 are more preferable.

When the isocyanate group-terminated polyurethane prepolymer is chain extended using a low molecular diamine as a chain extender, the ratio of the polyurethane prepolymer to the low molecular diamine is “NCO group of polyurethane prepolymer / NH of low molecular diamines. _The isocyanate index defined by a value 100 times the molar ratio of “ _two groups” is preferably 50 to less than 100, more preferably 50 to 98. Within this range, an amino group-terminated polyurethane resin can be obtained.
Moreover, when obtaining an isocyanate group terminal polyurethane resin, it is preferable that an isocyanate index is more than 100-200, and more than 100-150 is more preferable.

When a hydroxyl group-terminated polyurethane prepolymer is chain-extended using a diisocyanate compound as a chain extender to obtain an isocyanate group-terminated polyurethane polymer, the ratio of the polyurethane prepolymer to the diisocyanate compound is expressed as “NCO group / chain extender / The isocyanate index defined by a value 100 times the molar ratio of the “OH group of the polyurethane prepolymer” is preferably more than 100 to 200, more preferably 101 to 150.
Moreover, when obtaining a hydroxyl-terminated polyurethane polymer, it is preferable that this isocyanate index is less than 50-100, and 50-98 are more preferable.

  The molecular weight of the polyurethane polymer is preferably 4,000 to 500,000 in terms of number average molecular weight. More preferably, it is 8,000-250,000.

<Hydrolyzable silyl group>
In the present invention, the hydrolyzable silyl group is a silyl group having a hydrolyzable group. Specifically, a silyl group represented by -SiX _a R ³ _(3-a) is preferable. Here, a represents an integer of 1 to 3. a is preferably 2 to 3, and 3 is most preferable.
R ³ is a monovalent organic group having 1 to 20 carbon atoms, preferably a monovalent organic group having 1 to 6 carbon atoms. Specific examples include methyl group, ethyl group, propyl group, butyl group, pentyl group and the like. R ³ may have a substituent. Examples of the substituent include a methyl group and a phenyl group.
If the hydrolyzable silyl group has a plurality of R ^3, R ³ of the plurality of it may be the same or different from each other. That is, when a is 1, two R ³ bonded to one silicon atom (Si) are each independently a monovalent monovalent group having 1 to 20 carbon atoms that may have a substituent. An organic group is shown.

X represents a hydroxyl group (—OH) or a hydrolyzable group. Examples of the hydrolyzable group include -OR group (R is a hydrocarbon group having 4 or less carbon atoms). Such —OR group is preferably an alkoxy group or an alkenyloxy group, and particularly preferably an alkoxy group.
The alkoxy group or alkenyloxy group preferably has 4 or less carbon atoms. Specific examples include a methoxy group, an ethoxy group, a propoxy group, and a propenyloxy group. Among these, a methoxy group or an ethoxy group is more preferable. In this case, the curing rate of the curable composition can be further increased.
When a plurality of X are present in the hydrolyzable silyl group, the plurality of X may be the same as or different from each other. That is, when a is 2 or 3, each X independently represents a hydroxyl group or a hydrolyzable group.
As the hydrolyzable silyl group, a trialkoxysilyl group is preferable, a trimethoxysilyl group or a triethoxysilyl group is more preferable, and a trimethoxysilyl group is particularly preferable. This is because the storage stability of the silyl group-containing polymer (S) is good and the curing rate of the curable composition is high, which is suitable for the production of an adhesive.

<Introduction of hydrolyzable silyl group>
In the present invention, a hydrolyzable silyl group is introduced into the molecular terminal of the polyol compound, polyurethane prepolymer or polyurethane polymer. As a method for introducing a hydrolyzable silyl group, a method using an isocyanate silane (PQ1), a method using an aminosilane (PQ2), a method using a mercaptosilane (PQ3), a method using an epoxysilane (PQ4), And a method (PQ5) using hydrosilanes.

When the silyl group-containing polymer (S) has a urethane bond or a urea bond, the ratio (MU / MS mole) of the total amount (MU) of urethane bond and urea bond and the amount of hydrolyzable silyl group (MS). The ratio is not particularly limited, but MU / MS (molar ratio) is preferably 1/1 to 100/1. By being in this range, the adhesive force and flexibility of the adhesive body are controlled. Also, the stability of the adhesive force is improved. Urethane bonds are formed by the reaction of isocyanate groups and hydroxyl groups, and urea bonds are formed by the reaction of isocyanate groups and amino groups.
In the case of the silyl group-containing polymer (S2) or (S3), the molar ratio of MU / MS can be controlled by the molecular weight of the polyurethane prepolymer or polyurethane polymer.

<Method using isocyanate silanes (PQ1)>
In the method (PQ1), the terminal functional group of the polyol compound, polyurethane prepolymer or polyurethane polymer is a group capable of reacting with an isocyanate group, and hydrolysis is carried out by reacting the terminal functional group with isocyanate silanes. A functional silyl group is introduced.
Isocyanate silanes include isocyanate methyltrimethoxysilane, 2-isocyanatoethyltrimethoxysilane, 3-isocyanatopropyltrimethoxysilane, 4-isocyanatobutyltrimethoxysilane, 5-isocyanatepentyltrimethoxysilane, isocyanatemethyltriethoxysilane, 2-isocyanatoethyltriethoxysilane, 3-isocyanatopropyltriethoxysilane, 4-isocyanatobutyltriethoxysilane, 5-isocyanatepentyltriethoxysilane, isocyanatemethylmethyldimethoxysilane, 2-isocyanatoethylethyldimethoxysilane, 3-isocyanatopropyl Examples include trimethoxysilane or 3-isocyanatopropyltriethoxysilane. That.
Among these, 3-isocyanatopropyltrimethoxysilane or 3-isocyanatopropyltriethoxysilane is preferable.

Examples of the group capable of reacting with an isocyanate group include a hydroxyl group and an amino group. When a hydroxyl group is used, a polyol compound, a hydroxyl group-terminated polyurethane prepolymer, a hydroxyl group-terminated polyurethane prepolymer and a hydroxyl group-terminated polyurethane resin obtained by subjecting a hydroxyl group-terminated polyurethane prepolymer to a chain extension reaction using a diisocyanate compound, a low molecular diol Hydroxyl-terminated polyurethane resins obtained by reacting these groups can be used.
When an amino group is used, an amino group-terminated polyurethane resin obtained by subjecting an isocyanate group-terminated polyurethane prepolymer to a chain extension reaction using a low-molecular diamine can be used.

  A catalyst may be used for this reaction. A known urethanization reaction catalyst is used as the catalyst. Examples thereof include organic acid salts / organometallic compounds, tertiary amines and the like. Specific examples of organic acid salts and organometallic compounds include tin catalysts such as dibutyltin dilaurate (DBTDL), bismuth catalysts such as bismuth 2-ethylhexanoate [bismuth tris (2-ethylhexanoate)], zinc naphthenate Examples thereof include zinc catalysts such as cobalt catalysts such as cobalt naphthenate and copper catalysts such as copper 2-ethylhexanoate. Tertiary amines include triethylamine, triethylenediamine, N-methylmorpholine and the like.

<Method using aminosilanes (PQ2)>
In the method (PQ2), the terminal functional group of the polyurethane prepolymer or polyurethane polymer is a group capable of reacting with an amino group, and the hydrolyzable silyl group is formed by reacting the terminal functional group with aminosilanes. Introduce. If necessary, a group capable of reacting with an amino group may be introduced at the end of the polyol compound, polyurethane prepolymer or polyurethane resin.

Examples of aminosilanes include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyltriisopropoxysilane, 3-aminopropylmethyldimethoxysilane, 3-aminopropylmethyldiethoxysilane, 3- ( 2-aminoethyl) aminopropyltrimethoxysilane, 3- (2-aminoethyl) aminopropylmethyldimethoxysilane, 3- (2-aminoethyl) aminopropyltriethoxysilane, 3- (2-aminoethyl) aminopropylmethyl Diethoxysilane, 3- (2-aminoethyl) aminopropyltriisopropoxysilane, 3- (2- (2-aminoethyl) aminoethyl) aminopropyltrimethoxysilane, 3- (6-aminohexyl) aminopropyltri Methoxysila 3- (N-ethylamino) -2-methylpropyltrimethoxysilane, N- (2-aminoethyl) aminomethyltrimethoxysilane, N-cyclohexylaminomethyltriethoxysilane, N-cyclohexylaminomethyldiethoxymethylsilane 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenylaminomethyltrimethoxysilane, N-benzyl-3-aminopropyltrimethoxysilane, N-vinylbenzyl-3-aminopropyltriethoxysilane, N- (3-triethoxysilylpropyl) -4,5-dihydroimidazole, N-cyclohexylaminomethyltriethoxysilane, N-cyclohexylaminomethyldi Butoxy methyl silane, N- phenylaminomethyltrimethoxysilane, (2-aminoethyl) aminomethyl trimethoxy silane, N, N'-bis [3- (trimethoxysilyl) propyl] ethylenediamine, and the like.
Among these, 3-aminopropyltrimethoxysilane or 3-aminopropyltriethoxysilane is preferable.

  Examples of the group capable of reacting with an amino group include an isocyanate group, an acryloyl group, and a methacryloyl group. When an isocyanate group is used, an isocyanate group-terminated polyurethane prepolymer and a hydroxyl group-terminated polyurethane prepolymer further obtained by subjecting the diisocyanate compound to a chain extension reaction and an isocyanate group-terminated polyurethane prepolymer are further reduced. An isocyanate group-terminated polyurethane resin obtained by a chain extension reaction using a molecular diol compound can be used.

  When an acryloyl group or a methacryloyl group is used, an isocyanate group-terminated polyurethane prepolymer reacted with a hydroxyalkyl acrylate or hydroxyalkyl methacrylate, a polyol compound, a hydroxyl-terminated polyurethane prepolymer or a hydroxyl-terminated polyurethane polymer with acrylic acid Alternatively, a product obtained by reacting methacrylic acid can be used. Examples of hydroxyalkyl acrylates include hydroxyethyl acrylate and hydroxybutyl acrylate. Examples of hydroxyalkyl methacrylates include hydroxyethyl methacrylate and hydroxybutyl methacrylate. The reaction between an amino group and an isocyanate group is a urea bond formation reaction. In this reaction, the above-mentioned urethanization catalyst may be used. The reaction between an amino group and an acryloyl group is a Michael addition reaction.

<Method using mercaptosilanes (PQ3)>
In the method (PQ3), the terminal functional group of the polyurethane prepolymer or polyurethane polymer is a group capable of reacting with a mercapto group, and a hydrolyzable silyl group is obtained by reacting the terminal functional group with mercaptosilanes. Is introduced. If necessary, a group capable of reacting with a mercapto group may be introduced at the end of the polyol compound, polyurethane prepolymer or polyurethane polymer.
Mercaptosilanes include 3-mercaptopropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldiethoxysilane, mercaptomethyltrimethoxysilane, mercaptomethyltriethoxysilane. Etc. Among these, 3-mercaptopropyltrimethoxysilane or 3-mercaptopropyltriethoxysilane is preferable.

Examples of the group capable of reacting with a mercapto group include an isocyanate group, an acryloyl group, and an allyl group. The case of an isocyanate group and an acryloyl group is the same as in the case of the method using aminosilanes (PQ2). When an allyl group is used, the end of the polyurethane prepolymer or polyurethane polymer can be converted to an isocyanate group and then reacted with allyl alcohol to form an allyl group.
The reaction between the mercapto group and the isocyanate group is the same as the urethanization reaction, and a catalyst may be used. The reaction between the mercapto group and the acryloyl group or allyl group is preferably performed using a radical initiator. Examples of the radical initiator include azobisisobutyronitrile (AIBN).

<Method using epoxy silanes (PQ4)>
In the method (PQ4), the terminal functional group of the polyol compound, polyurethane prepolymer or polyurethane polymer is a group capable of reacting with an epoxy group, and by reacting the terminal functional group with epoxy silanes. A hydrolyzable silyl group is introduced. If necessary, a group capable of reacting with an epoxy group may be introduced at the end of the polyol compound, polyurethane prepolymer or polyurethane polymer.
As epoxy silanes, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane and the like are preferable. Among these, 3-glycidoxypropyltrimethoxysilane or 3-glycidoxypropyltriethoxysilane is preferable.
Examples of the group capable of reacting with the epoxy group include a hydroxyl group and an amino group. Each is the same as in the method (PQ1) using isocyanate silanes. As the catalyst in the reaction with the epoxy group, known ones such as amines and acid anhydrides are used. Examples include chain aliphatic polyamines, alicyclic polyamines, aromatic polyamines, modified aliphatic polyamines, imidazole compounds, and the like. In particular, tertiary amines such as N, N-dimethylpiperazine, triethylenediamine, 2,4,6-tris (dimethylaminomethyl) phenol (DMP-30) and benzyldimethylamine (BDMA) are preferable.

<Method using hydrosilanes (PQ5)>
In method (PQ5), the terminal functional group of the polyurethane prepolymer or polyurethane polymer is a group capable of hydrosilylation reaction, and a hydrolyzable silyl group is introduced by reacting the terminal functional group with hydrosilanes. To do. If necessary, a group capable of hydrosilylation reaction may be introduced at the end of the polyol compound, polyurethane prepolymer or polyurethane polymer.
Examples of hydrosilanes include trimethoxysilane, triethoxysilane, methyldiethoxysilane, methyldimethoxysilane, phenyldimethoxysilane, 1- [2- (trimethoxysilyl) ethyl] -1,1,3,3-tetramethyldi Examples thereof include siloxane.
Examples of groups capable of undergoing hydrosilylation include acryloyl groups and allyl groups. Each is the same as the method (PQ3) using mercaptosilanes. It is preferable to use a hydrosilylation catalyst for this reaction. Examples of the hydrosilylation catalyst include chloroplatinic acid.

<Acrylic polymer (P)>
In the present invention, an acrylic polymer (P) is used together with the silyl group-containing polymer (S) in order to obtain a curable composition. In the following description, (meth) acrylic acid means one or both of acrylic acid and methacrylic acid, and the same applies to (meth) acrylic acid esters and the like.
The acrylic polymer (P) according to the present invention is preferably a (meth) acrylic acid ester polymer having 80 to 100% by mass of (meth) acrylic acid ester units. Specifically, a homopolymer composed of one kind of (meth) acrylic acid ester unit, a copolymer having two or more (meth) acrylic acid ester units, one or more kinds of (meth) acrylic acid ester units and ( Any of copolymers having at least one other monomer unit other than (meth) acrylate is preferred.

The following are mentioned as a (meth) acrylic acid ester unit.
(Meth) acrylic acid alkyl ester: From the point of adhesiveness, (meth) acrylic acid alkyl ester having an alkyl group having 1 to 12 carbon atoms is preferable, for example, methyl (meth) acrylate, ethyl (meth) acrylate. , (Meth) acrylic acid propyl, (meth) acrylic acid-n-butyl, (meth) acrylic acid isobutyl, (meth) acrylic acid pentyl, (meth) acrylic acid hexyl, (meth) acrylic acid cyclohexyl, (meth) acrylic Acid-2-ethylhexyl, isooctyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, and the like.
(Meth) acrylic acid hydroxyalkyl ester: (meth) acrylic acid-2-hydroxyethyl, (meth) acrylic acid-2-hydroxypropyl, (meth) acrylic acid-3-hydroxypropyl, (meth) acrylic acid-2 -Hydroxybutyl, (meth) acrylic acid-3-hydroxybutyl, (meth) acrylic acid-4-hydroxybutyl and the like.
-(Meth) acrylamide: acrylamide, methacrylamide, N-methylacrylamide, N-methylmethacrylamide, N-methylolacrylamide, N-methylolmethacrylamide and the like.
・ (Meth) acrylic acid monoalkylaminoalkyl ester: (meth) acrylic acid monomethylaminoethyl, (meth) acrylic acid monoethylaminoethyl, (meth) acrylic acid monomethylaminopropyl, (meth) acrylic acid monoethylaminopropyl, etc. .
-(Meth) acrylic acid dialkylaminoalkyl ester.
Ethylenically unsaturated carboxylic acid: acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, citraconic acid and the like.
Examples of the monomer unit other than (meth) acrylic acid ester include the following.
-Vinyl esters: vinyl acetate, vinyl propionate, etc.
-Styrene monomers: Styrene, α-methylstyrene, etc.
Nitrile monomer: Acrylonitrile, methacrylonitrile, etc. The above monomer units may be used alone or in combination of two or more.

The (meth) acrylic acid ester polymer may have one or both of a hydroxyl group and a carboxyl group.
In order to obtain a (meth) acrylic acid ester polymer having one or both of a hydroxyl group and a carboxyl group, (meth) acrylic acid hydroxyalkyl ester and ethylenically unsaturated carboxylic acid are used as part or all of the monomers during polymerization. One or both of the acids may be used. The proportion of the (meth) acrylic acid hydroxyalkyl ester in the monomer during polymerization for obtaining the (meth) acrylic acid ester polymer is preferably 0 to 20% by mass, more preferably 0 to 10% by mass. The ratio of the ethylenically unsaturated carboxylic acid in the monomer during polymerization for obtaining the (meth) acrylic acid ester polymer is preferably 0 to 25% by mass, and more preferably 2 to 10% by mass. The total of these two types of monomers is preferably 2 to 15% by mass.
The mass average molecular weight of the (meth) acrylic acid ester polymer is preferably 10,000 to 1,000,000, and more preferably 10,000 to 800,000. If the weight average molecular weight of the (meth) acrylic acid ester polymer is 10,000 or more, the heat resistance and adhesion durability of the pressure-sensitive adhesive composition can be increased, and if it is 1,000,000 or less, the shape of the adherend The followability to the change can be increased.

<Method for producing adhesive body>
When the silyl group-containing polymer (S1) is used, the pressure-sensitive adhesive production method of the present invention is a step of producing a silyl group-containing polymer (S1) by introducing a hydrolyzable silyl group into the molecular terminal of the polyol compound (PP1A). And a step (PP1B) of producing a pressure-sensitive adhesive by curing the curable composition containing the silyl group-containing polymer (S1) and the acrylic polymer (P).
When the silyl group-containing polymer (S2) is used, a process of producing a polyurethane prepolymer by reacting a polyol compound and a polyisocyanate compound (PP2A), and a hydrolyzable silyl group at the molecular terminal of the polyurethane prepolymer A pressure-sensitive adhesive is produced by curing a curable composition containing the step (PP2B) for introducing and producing the silyl group-containing polymer (S2) and the silyl group-containing polymer (S2) and the acrylic polymer (P). Step (PP2C).
When the silyl group-containing polymer (S3) is used, a step of producing a polyurethane prepolymer by reacting a polyol compound and a polyisocyanate compound (PP3A), and the polyurethane prepolymer are chain extended using a chain extender. A step of producing a polyurethane resin by reacting (PP3B), a step of producing a silyl group-containing polymer (S3) by introducing a hydrolyzable silyl group into the molecular terminal of the polyurethane resin (PP3C), and the silyl group-containing And a step (PP3D) of producing a pressure-sensitive adhesive by curing a curable composition containing the polymer (S3) and the acrylic polymer (P).
Here, the steps (PP2A) and (PP3A) for producing the polyurethane prepolymer are the same. The steps (PP1A), (PP2B) and (PP3C) for introducing a hydrolyzable silyl group are the same. Further, the steps (PP1B), (PP2C) and (PP3D) for producing a pressure-sensitive adhesive by curing the curable composition are the same.

<Process for producing polyurethane prepolymer (PP2A) (PP3A)>
The polyurethane prepolymer is obtained by reacting a polyol compound and a polyisocyanate compound. The reaction rate is as described above. A catalyst may be used for this reaction. As the catalyst, the above-mentioned urethanization reaction catalyst is used. The reaction temperature is preferably 40 to 160 ° C, more preferably 80 to 120 ° C.

<Process for producing polyurethane resin (PP3B)>
The polyurethane resin is obtained by subjecting a polyurethane prepolymer to a chain extension reaction using a chain extender. The reaction rate is as described above. A catalyst may be used for this reaction. As the catalyst, the above-mentioned urethanization reaction catalyst is used. The reaction temperature is preferably 40 to 160 ° C, more preferably 80 to 120 ° C.

<Step of introducing hydrolyzable silyl group (PP1A) (PP2B) (PP3C)>
The step of introducing a hydrolyzable silyl group into the polyol compound, polyurethane prepolymer or polyurethane resin is as described in the above methods (PQ1) to (PQ5). The ratio of introducing a hydrolyzable silyl group (hereinafter sometimes referred to as a hydrolyzable silyl group introduction ratio) is 50 to 100 mol%, assuming that all the terminals capable of reacting theoretically are 100 mol%. It is preferable to introduce, more preferably 80 to 100 mol%.

<The process of manufacturing a pressure-sensitive adhesive by curing a curable composition (PP1B) (PP2C) (PP3D)>
A curable composition containing the silyl group-containing polymer (S) and the acrylic polymer (P) is cured to produce an adhesive.
The curable composition concerning this invention may contain the polymer which has another hydrolysable silyl group. The proportion of the polymer having other hydrolyzable silyl groups is preferably 30% by mass or less, more preferably 10% by mass or less, based on the entire curable composition.
The silyl group-containing polymer (S), the acrylic polymer (P), and optionally a polymer having other hydrolyzable silyl groups, in the presence or absence of a solvent, including various additives described below, It is preferable that the composition is sufficiently mixed to form a curable composition. In this curable composition, the ratio of the silyl group-containing polymer (S) and the acrylic polymer (P) is (S) :( P) in a mass ratio of 0.1: 99.9 to 99.9: 0. 1 and preferably 1:99 to 95: 5, more preferably 40:60 to 95: 5, and even more preferably 70:30 to 95: 5. When the ratio of the acrylic polymer (P) is 0.1 parts by mass or more with respect to 100 parts by mass in total of (S) and (P), the adhesive force can be changed, and is 5 parts by mass or more. Further, the adhesive force can be changed, and if it is 99.9 parts by mass or less, an increase in adhesive force with time can be suppressed, and if it is 60 parts by mass or less, an increase in adhesive force with time can be further suppressed. And an adhesive having excellent durability can be obtained.
Moreover, since it is excellent in the softness | flexibility of a hardening body, it is preferable that a curable composition contains a silyl group containing polymer (S1) and an acrylic polymer (P).

<Additives>
The curable composition according to the present invention may contain an additive. In the curable composition, it is preferable not to use a plasticizer. In particular, it is preferable not to use an ester plasticizer such as dioctyl phthalate. This is because when an ester plasticizer is used, the adhesive force between the cured body and the substrate is lowered, and adhesive deposits may occur.
[Curing agent]
The curable composition according to the present invention is cured by contact with water. Therefore, it reacts with water in the atmosphere and is cured by moisture. Also, just prior to curing, water (H 2 _O) may be added as a curing agent. In this case, the amount of water added is 0.01 to 5 parts by mass with respect to 100 parts by mass of the total amount of the silyl group-containing polymer (S) and the other polymer having hydrolyzable silyl groups. Preferably, 0.01-1 mass part is more preferable, and 0.05-0.5 mass part is especially preferable. Curing can be effectively accelerated by setting the addition amount of the curing agent to 0.01 parts by mass or more, and the pot life at the time of use can be secured by setting the addition amount of the curing agent to 5 parts by mass or less.

[Curing catalyst]
The curable composition preferably contains a curing catalyst (curing accelerator) for accelerating the hydrolysis and / or crosslinking reaction of the hydrolyzable silyl group.
As such a curing catalyst, a known catalyst can be appropriately used as a component for promoting the reaction of the hydrolyzable silyl group. Specific examples include dibutyltin diacetate, dibutyltin dilaurate, dioctyltin _{dilaurate, (n-C 4 H 9} ) 2 Sn (OCOCH = CHCOOCH 3) 2, (n-C 4 H 9) 2 Sn (OCOCH = CHCOO (n _{-C 4 H 9)) 2,} (n-C 8 H 17) 2 Sn (OCOCH = CHCOOCH 3) 2, (n-C 8 H 17) 2 Sn (OCOCH = CHCOO (n-C 4 H 9)) ₂ , (n-C ₈ H ₁₇ ) ₂ Sn (OCOCH═CHCOO (iso-C ₈ H ₁₇ )) ₂ Organotin carboxylates such as ₂ ; (nC ₄ H ₉ ) ₂ Sn (SCH ₂ COO), ( _{n-C 8 H 17) 2} Sn (SCH 2 COO), (n-C 8 H 17) 2 Sn (SCH 2 CH 2 COO), (n-C 8 H 17) 2 _{n (SCH 2 COOCH 2 CH 2} OCOCH 2 S), (n-C 4 H 9) 2 Sn (SCH 2 COO (iso-C 8 H 17)) 2, (n-C 8 H 17) 2Sn (SCH 2 _{COO (iso-C 8 H 17} )) 2, (n-C 8 H 17) 2 Sn (SCH 2 COO (n-C 8 H 17)) 2, (n-C 4 H 9) such as 2 SnS including Sulfur organotin compounds; organotin oxides such as (nC ₄ H ₉ ) ₂ SnO, (nC ₈ H ₁₇ ) ₂ SnO; ethyl silicate, dimethyl maleate, diethyl maleate, dioctyl maleate, dimethyl phthalate, an ester compound selected from the group consisting of diethyl phthalate and dioctyl phthalate, reaction products of the organic tin _{oxide; (n-C 4 H 9} ) 2 Sn (acac) _{, (N-C 8 H 17} ) 2 Sn (acac) 2, (n-C 4 H 9) 2 Sn (OC 8 H 17) (acac), (n-C 4 H 9) 2 Sn (OC (CH _{3) CHCO 2 C 2 H 5} ) 2, (n-C 8 H 17) 2 Sn (OC (CH 3) CHCO 2 C 2 H 5) 2, (n-C 4 H 9) 2 Sn (OC 8 H ₁₇ ) (OC (CH ₃ ) CHCO ₂ C ₂ H ₅ ), chelating tin compounds such as bisacetylacetonatotin (wherein acac means an acetylacetonato ligand, OC (CH ₃ ) CHCO ₂ C ₂ H ₅ means an ethyl acetoacetate ligand. ); Reaction product of alkoxysilane selected from the group consisting of tetramethoxysilane, tetraethoxysilane, and tetrapropoxysilane and the above-mentioned chelated tin compound; (nC ₄ H ₉ ) ₂ (CH ₃ COO) SnOSn (OCO)
_{CH 3) (n-C 4} H 9) 2, (n-C 4 H 9) 2 (CH 3 O) SnOSn (OCH 3) (n-C 4 H 9) 2 , etc. -SnOSn--containing organic tin And tin compounds such as compounds.

  As further specific examples of the curing catalyst, divalent tin carboxylates such as tin 2-ethylhexanoate, tin n-octylate, tin naphthenate or tin stearate; octyl acid, oleic acid, naphthenic acid or stearin Metal salts other than tin of organic carboxylic acids such as acids; bismuth carboxylates such as calcium carboxylate, zirconium carboxylate, iron carboxylate, vanadium carboxylate, bismuth tris-2-ethylhexanoate, lead carboxylate, carboxylic acid Titanium or nickel carboxylate; titanium alkoxides such as tetraisopropyl titanate, tetrabutyl titanate, tetramethyl titanate, tetra (2-ethylhexyl titanate); aluminum isopropylate, mono-sec-butoxyaluminum diisopropylate Aluminum alkoxides; zirconium alkoxides such as zirconium-n-propylate and zirconium-n-butyrate; titanium chelates such as titanium tetraacetylacetonate, titanium ethylacetoacetate, titanium octylene glycolate and titanium lactate; aluminum trisacetyl Aluminum chelates such as acetonate, aluminum trisethyl acetoacetate, diisopropoxy aluminum ethyl acetoacetate; zirconium compounds such as zirconium tetraacetylacetonate, zirconium bisacetylacetonate, zirconium acetylacetonate bisethylacetoacetate, zirconium acetate Acidic compounds such as phosphoric acid, p-toluenesulfonic acid or phthalic acid; Aliphatic monoamines such as amine, hexylamine, octylamine, decylamine and laurylamine; Aliphatic diamines such as ethylenediamine and hexanediamine; Aliphatic polyamines such as diethylenetriamine, triethylenetetramine and tetraethylenepentamine; Piperidine and piperazine Heterocyclic amines such as 1,8-diazabicyclo (5.4.0) undecene-7; aromatic amines such as metaphenylenediamine; alkanolamines such as monoethanolamine, diethanolamine or triethanolamine; triethylamine Trialkylamines such as: the above amines and aliphatic monocarboxylic acids (formic acid, acetic acid, octylic acid, 2-ethylhexanoic acid, etc.), aliphatic polycarboxylic acids (succinic acid, malonic acid, succinic acid, glutaric acid, adipine) Acid), aromatic monocarboxylic acids (benzoic acid, toluic acid, ethylbenzoic acid, etc.), aromatic polycarboxylic acids (phthalic acid, isophthalic acid, terephthalic acid, nitrophthalic acid, trimellitic acid, etc.), phenolic compounds (phenol) , Resorcinol, etc.), sulfonic acid compounds (alkylbenzenesulfonic acid, toluenesulfonic acid, benzenesulfonic acid, etc.), organic acids such as phosphoric acid compounds, and acids such as inorganic acids such as hydrochloric acid, bromic acid, sulfuric acid, etc. ~ Tertiary ammonium-acid salts; triethylmethylammonium hydroxide, trimethylbenzylammonium hydroxide, hexyltrimethylammonium hydroxide, octyltrimethylammonium hydroxide, decyltrimethylammonium hydroxide, dodecyltrimethylammonium Droxide, octyldimethylethylammonium hydroxide, decyldimethylethylammonium hydroxide, dodecyldimethylethylammonium hydroxide, dihexyldimethylammonium hydroxide, dioctyldimethylammonium hydroxide, didecyldimethylammonium hydroxide, didodecyldimethylammonium hydroxide, etc. And ammonium compounds such as various modified amines used as curing agents for epoxy resins.

These curing catalysts may be used alone or in combination of two or more. When two or more types are combined, for example, the above-mentioned metal-containing compound such as a reaction product of the divalent tin carboxylate, organotin carboxylate or organotin oxide and an ester compound, an aliphatic monoamine or other amine compound It is preferable to combine these because excellent curability can be obtained.
When the curing catalyst is added, the addition amount is 0.001 to 10 parts by mass with respect to 100 parts by mass of the total amount of the silyl group-containing polymer (S) and the other polymer having hydrolyzable silyl groups. It is preferable that there is 0.01 to 5 parts by mass. By making the addition amount of the curing catalyst 0.001 part by mass or more, the curing rate can be effectively accelerated, and by making the addition amount of the curing catalyst 10 parts by mass or less, the pot life during use can be secured.

[solvent]
The curable composition according to the present invention has a low viscosity and can be applied without a solvent, but may contain a solvent.
The solvent is not particularly limited. For example, aliphatic hydrocarbons, aromatic hydrocarbons, halogenated hydrocarbons, alcohols, ketones, esters, ethers, ester alcohols, ketone alcohols, ether alcohols , Ketone ethers, ketone esters or ester ethers.
Among these, it is preferable to use alcohols as the solvent because the storage stability of the curable composition can be improved. The alcohol is preferably an alkyl alcohol having 1 to 10 carbon atoms, more preferably methanol, ethanol, isopropyl alcohol, isopentyl alcohol or hexyl alcohol, and further preferably methanol or ethanol. In particular, when methanol is used, the curing time of the curable composition can be increased by increasing the amount of addition. This is an effective technique for prolonging the so-called pot life of the curable composition until it reaches a predetermined viscosity after preparation.
When adding a solvent to a curable composition, the addition amount is 500 mass parts or less with respect to 100 mass parts of total amounts of a silyl group containing polymer (S), an acrylic polymer (P), and another polymer. It is preferable that it is 1-100 mass parts. When the addition amount exceeds 500 parts by mass, the cured product may shrink as the solvent volatilizes.

[Dehydrating agent]
In order to improve the storage stability, the curable composition according to the present invention may contain a small amount of a dehydrating agent as long as the effects of the present invention are not impaired.
Specific examples of such dehydrating agents include alkyl orthoformate such as methyl orthoformate and ethyl orthoformate; alkyl orthoacetate such as methyl orthoacetate and ethyl orthoacetate; methyltrimethoxysilane, vinyltrimethoxysilane, tetramethoxysilane or tetra Examples include hydrolyzable organic silicone compounds such as ethoxysilane; hydrolyzable organic titanium compounds and the like. Among these, vinyltrimethoxysilane or tetraethoxysilane is preferable from the viewpoints of cost and dehydration ability.
When adding a dehydrating agent to a curable composition, the addition amount is 0.001 with respect to 100 mass parts of the total amount of a silyl group containing polymer (S), an acrylic polymer (P), and another polymer. It is preferable that it is -30 mass parts, and it is more preferable that it is 0.01-10 mass parts.

[Other additives]
You may mix | blend the following filler, reinforcing agent, stabilizer, flame retardant, antistatic agent, mold release agent, antifungal agent, etc. with a curable composition.
Examples of the filler or reinforcing agent include carbon black, aluminum hydroxide, calcium carbonate, titanium oxide, silica, glass, bone powder, wood powder, or fiber flake.
Examples of the stabilizer include an antioxidant, an ultraviolet absorber, and a light stabilizer.
Examples of the flame retardant include chloroalkyl phosphate, dimethylmethylphosphonate, ammonium polyphosphate, or an organic bromine compound.
Examples of the mold release agent include wax, soaps, or silicone oil. Examples of the antifungal agent include pentachlorophenol, pentachlorophenol laurate, bis (tri-n-butyltin) oxide, and the like.
Moreover, you may add an adhesiveness imparting agent to the curable composition for the purpose of improving adhesiveness with a base material.

<Adhesive>
The curable composition according to the present invention is obtained by mixing a silyl group-containing polymer (S), an acrylic polymer (P), other polymers optionally blended, and additives that are added as necessary. It is done.
The pressure-sensitive adhesive body of the present invention is obtained by curing the curable composition. When the curable composition is cured, an adhesive body having a relatively low adhesive strength is obtained. That is, the pressure-sensitive adhesive body of the present invention is a cured body obtained by curing the curable composition.
The peel adhesive strength of the pressure-sensitive adhesive body of the present invention is preferably 8 N / 25 mm or less, more preferably 0 N / 25 mm to 8 N / 25 mm or less, more preferably 0 N / 25 mm to 1 N / 25 mm or less, 0.005 to 0 .8 N / 25 mm is particularly preferable. It is preferable that the curable composition concerning this invention does not contain the additive which increases adhesiveness.

The curable composition containing the silyl group-containing polymer (S) and the acrylic polymer (P) according to the present invention has a low viscosity and good coatability. Therefore, good coating properties can be obtained without using a solvent, so that the curable composition can be made solvent-free when the pressure-sensitive adhesive is formed. Moreover, since this composition is excellent in sclerosis | hardenability, when it contacts with a water | moisture content, it hardens | cures rapidly and firmly (moisture hardening), and a hardening body is obtained. A hydrolyzable silyl group (—SiX _a R ³ _(3-a) ) contributes to the moisture curing.
Moreover, when it is applied on a substrate and cured, good adhesion to the substrate is obtained. The cured body after curing has good flexibility, good surface wettability, and low tackiness. Therefore, it is suitable as an adhesive layer, and has good wettability and adhesion to an adherend and good removability.
Further, by changing the content ratio of the silyl group-containing polymer (S) and the acrylic polymer (P), it is possible to easily adjust the adhesive force in the region of low adhesion to low adhesion.

In particular, when the silyl group-containing polymer (S) has a polar bond such as a urethane bond or a urea bond, better fine tackiness or low tackiness can be obtained. Although the reason is not clear, it is considered that such a polar bond acts in the direction of increasing the cohesive force in the cured body, the adhesiveness of the adhesive body to the base material, and the adhesiveness to the adherend. On the other hand, the hydrolyzable silyl group is considered to act in the direction of lowering the adhesiveness of the adhesive to the adherend. And it is thought that these interactions contribute to the slight tackiness or low tackiness.
In addition, since the position where the hydrolyzable silyl group is introduced is the molecular end of the silyl group-containing polymer (S), the cohesive force can be increased without hindering the molecular motion, and the adhesive force is stably exhibited. Can do.
Therefore, the adhesive strength of the adhesive body is controlled by controlling the ratio (MU / MS molar ratio) between the total amount (MU) of urethane bonds and urea bonds and the amount of hydrolyzable silyl groups (MS). be able to.

In the pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer on the base material, and the pressure-sensitive adhesive layer is peelably adhered to the adherend, the adhesion (adhesiveness) between the pressure-sensitive adhesive layer and the base material is It is preferable that the pressure-sensitive adhesive layer and the adherend are peeled off without any adhesive residue. When the curable composition of this invention is apply | coated on a base material and this curable composition is hardened, the hardened | cured hardening body (adhesive body layer) and a base material will adhere | attach favorably. A polar bond such as a urethane bond or a urea bond is considered to contribute to good adhesion to the substrate.
In addition, when a curable composition hardens | cures, it is thought that it adheres to a base material. On the other hand, the hardened | cured hardening body shows adhesiveness, without adhering to a to-be-adhered body. For this reason, it is thought that the adhesive residue on a to-be-adhered body is suppressed.
Further, when the silyl group-containing polymer (S) has a polar bond such as a urethane bond or a urea bond, the compatibility with the acrylic polymer (P), which is a relatively polar polymer, is improved. . For this reason, it is easy to obtain a uniform cured body, it is highly effective in suppressing the destruction (such as throwing destruction) of the pressure-sensitive adhesive body at the time of peeling, and the adhesive residue is unlikely to occur.

  Moreover, in the cured body (adhesive body) obtained by curing the curable composition of the present invention, good wettability to the adherend can be obtained. It is considered that the flexibility of the structure derived from polyol contributes to such good wettability. That is, when the polyol has a linear structure that does not have a branched structure, it has a molecular structure that can move freely, and acts in the direction of increasing flexibility. Furthermore, the polarity of the structure in which the polyol mainly has a polyether skeleton is relatively low. With such a molecular structure, it is considered that good wettability can be obtained on the adherend. In particular, the longer the chain length of the polyether skeleton, the higher the flexibility and wettability.

<Curing of curable composition>
The pressure-sensitive adhesive body of the present invention is obtained by curing the curable composition of the present invention. It is also possible to mold after curing of the curable composition. For example, the curable composition can be cured into an appropriate shape such as a sheet and then molded into a predetermined shape by die cutting or the like, and used alone as an adhesive. However, it is preferable to apply the curable composition to a substrate and cure it to use as a laminate.
The curing conditions for the curable composition are set as necessary. For example, a curable composition to which a curing catalyst is added is prepared. A predetermined amount of water is added to this as a curing agent and mixed well. This is coated on a substrate. The coating thickness is appropriately set. Thereafter, the curable composition can be cured by heating in an oven or the like and curing at room temperature. It is also effective to leave it in a humidified environment when curing at room temperature or after curing. Heating by an oven or the like is appropriately set depending on the heat-resistant temperature of the substrate. For example, it is preferable to leave in an environment of 60 to 120 ° C. for about 1 to 30 minutes. In particular, when a solvent is used, it is preferable to set a certain drying time. However, rapid drying is not preferable because it causes foaming. Steam may also be applied in or after removal from the oven.

Application of the curable composition can also be performed continuously. That is, a curable composition in which a predetermined amount of water is mixed is applied to the substrate taken out from the roll, and is heated and dried in an in-line oven. A separator is combined with the obtained molded body (laminated body) as necessary, and wound. A pressure-sensitive adhesive body formed by storing and curing in a room temperature environment humidified as necessary is obtained. As another coating method, the substrate and the separator may be reversed in the above method.
That is, it may be coated on the separator first, and the substrate may be attached later.

<Laminated body (adhesive sheet)>
The present invention provides a laminate having at least one base material layer and an adhesive layer made of the adhesive of the present invention. When the laminate is in the form of a sheet, the laminate becomes an adhesive sheet. An adhesive tape can be obtained by molding the laminate into a tape shape.
In addition, when a curable composition is applied to a separator which will be described later without using a base material and cured to obtain a cured body, the separator is then peeled off, so that the adhesive body can be handled alone. In this case, for example, a double-sided pressure-sensitive adhesive sheet is obtained. The curable composition according to the present invention has a low viscosity and excellent coating properties even when no solvent is used. For this reason, favorable coating is possible also to a separator. Specifically, by applying a curable composition to a separator, drying by heating, laminating another separator, and curing, a pressure-sensitive adhesive sheet only having no base material is obtained. can get. At this time, without using another separator, the back surface of the separator coated first may be wound to produce a roll of an adhesive.

The laminated body may have another layer as needed. For example, an adhesive layer (including a primer layer) may be provided between the base material layer and the pressure-sensitive adhesive layer to prevent peeling of the base material and the pressure-sensitive adhesive body. Moreover, you may provide the buffer body layer which consists of a foam etc. between a base material layer and an adhesive body layer. Further, a conductive material layer may be provided between the base material layer and the adhesive layer. The conductive material layer is obtained by applying a conductive material such as a metal-based conductive material, an ionic conductive material, or a carbon-based conductive material to the base material layer. The conductive material may be applied alone or in combination with a binder such as various resins. Moreover, you may provide a separator (release liner) layer on the opposite side to the base material layer of an adhesion body layer. Moreover, you may provide a printing layer in the opposite side to the adhesion body layer of a base material layer. When a printing layer is provided, printing can be performed and design properties can be enhanced. Moreover, you may provide an adhesive body layer on both surfaces on both sides of a base material layer.
In this case, a double-sided pressure-sensitive adhesive sheet or the like is obtained.

<Base material>
The material of the substrate is not particularly limited. Preferred examples include polyesters such as polyethylene terephthalate (PET); polyolefins such as polyethylene, polypropylene, and polyethylene-polypropylene copolymers (block copolymers and random copolymers); halogenated polyolefins such as polyvinyl chloride; Examples include paper such as cardboard; cloth such as woven fabric and nonwoven fabric; metal foil such as aluminum foil. These base materials may be used in combination. For example, you may use the laminated body which laminated | stacked the PET layer, the metal foil layer, and the polyethylene layer.
The surface of the substrate may not be processed in advance. In particular, the joint surface with the pressure-sensitive adhesive layer made of paper is difficult to be peeled off due to the adhesive effect accompanying the curing of the curable composition without performing prior processing.
On the other hand, when using polyolefin for a base material, it is preferable to process beforehand the surface which coats a curable composition. This is because the peel adhesive strength may be lowered on an untreated surface. That is, examples of the prior treatment for the surface of the substrate on which the curable composition of the substrate using polyolefins is applied include corona treatment (corona discharge treatment) and primer treatment. In particular, the corona treatment is preferable because the treatment is simple and the process can be simplified.
For example, a corona treatment is performed on one side of a polypropylene film having a thickness of 100 μm, and a curable composition is applied to the treated surface. Heat and dry after coating. The film thus obtained can be used as a separator as it is on the surface (back surface) on which no adhesive is provided. That is, an adhesive film can be manufactured by winding this film as it is. That is, it can be wound into a roll without interposing a separator.

<Adhesive layer>
In the pressure-sensitive adhesive sheet or the like of the present invention, the thickness of the pressure-sensitive adhesive layer is not particularly limited. For example, from the viewpoint of coating accuracy, 5 μm or more is preferable, 20 μm or more is more preferable, and 30 μm or more is more preferable. Further, from the viewpoint of stability of adhesive strength and economical efficiency, it is preferably 200 μm or less, more preferably 100 μm or less, and more preferably 80 μm or less.
<Separator>
You may affix a separator to the adhesion surface (surface to which a to-be-adhered body is stuck) of said adhesive body layer.
As the separator, in addition to papers subjected to surface treatment with a general release agent, the above-mentioned untreated polyolefins can be used. Moreover, what laminated | stacked polyolefins on base materials, such as paper, can also be used. Silicone oil contained in a conventional separator causes contamination of electronic components. However, when polyolefins are used in the separator, contamination with silicone oil or the like can be prevented. This is useful when the adhesive sheet is applied as a protective sheet for electronic parts and the like. In addition, when polyolefins are used alone as separators, waste can be easily recycled.

<Use of adhesive sheet>
By using the pressure-sensitive adhesive body of the present invention, it is possible to obtain a pressure-sensitive adhesive sheet having particularly good wettability and adhesion to an adherend and having low adhesive force and excellent removability. In addition, a pressure-sensitive adhesive sheet in which the peel charge amount is suppressed and the high-speed peel property is excellent can be obtained. Accordingly, the application of the pressure-sensitive adhesive sheet specifically includes a protective sheet for electronic materials such as an electronic substrate and an IC chip; a protective sheet for optical members such as a polarizing plate, a light diffusing plate, a light diffusing sheet, and a prism sheet; Protective sheets for automobiles; protective sheets for automobiles; surface protective films for building boards; decorative sheets for wall coverings; surface protection of products such as metal plates, painted steel plates, synthetic resin plates, decorative plywood, heat reflecting glass, etc. . In the case of a relatively large protective sheet such as a protective sheet for automobiles or a temporary fixing application, there may be a case where a certain adhesive force of a low adhesive region is required so as not to be peeled off by wind or the like. The surface protection film for building boards is used for flooring protection and is removed after the interior finishes.
For surface protection applications of products such as metal plates, painted steel plates, synthetic resin plates, decorative plywood, and heat-reflective glass, make sure that there is no dust adhesion or scratches, and that the surfaces of various adherends are contaminated with adhesives after use. It is required to be easily removed.

The protective sheet and the protective tape are peeled and removed when the temporary fixing of the parts and the role of protection are completed. However, when the protective sheet is peeled off from the attached member, static electricity (so-called peeling charge) is generated between the protective sheet and the component. There is a problem that this static electricity has an adverse effect on the circuit of the electronic component, and dust and dirt easily adhere to the surface of the member due to the static electricity. Further, the surface protective film of the liquid crystal display (LCD) is also peeled off during use. When the protective film is peeled from the liquid crystal display, peeling charging may occur.
This peeling electrification may disturb the liquid crystal alignment and disturb the image.
Therefore, in the pressure-sensitive adhesive sheet that is peeled off after sticking, it is required to suppress the generation of static electricity due to peeling charging and to promptly remove the generated static electricity. This is because the surface charge of the adherend causes adhesion of foreign matter and dust to the adherend or causes the function of the adherend to deteriorate.

In general, the tensile force (peeling strength) required to peel the adhesive sheet tends to increase as the tensile speed (peeling speed) increases. For example, it is preferable that a surface protective sheet such as an electronic component such as a display, a polarizing plate, an electronic substrate, and an IC chip can be smoothly peeled at a high speed. It is required that the peel strength when peeling at high speed does not increase compared to the peel strength when peeling at low speed. That is, the protective sheet is required to have low peel strength and high speed peel characteristics.
The pressure-sensitive adhesive sheet of the present invention can satisfy such requirements, and in particular, the pressure-sensitive adhesive sheet of the present invention is suitable as a protective sheet that is peeled off during the manufacturing process, such as a protective sheet for electronic materials and a protective sheet for optical members. It is. This is because the adhesive strength is low and the re-peelability is good, the peel charge amount is small, and the high-speed peel property is excellent.

The pressure-sensitive adhesive body of the present invention is excellent in flexibility and wettability. For this reason, even if unevenness exists on the surface of the adherend, good adhesion is ensured. Therefore, it is suitable as an adhesive sheet for protecting an optical member.
That is, the pressure-sensitive adhesive sheet of the present invention is suitable as a protective film for a light diffusing plate or a prism sheet, particularly as a protective film for the uneven surface. Further, the optical member having the pressure-sensitive adhesive sheet of the present invention attached thereto has a small change in the adhesive strength of the pressure-sensitive adhesive with time, so that it can be peeled off with a low peel strength, and its peel strength is hardly changed. For this reason, the optical member can be stored for a long period of time.

In addition, the pressure-sensitive adhesive sheet of the present invention has excellent adhesion and can be easily peeled off with a low peel strength even though there is almost no deviation within the sticking surface of the stuck adherend. It can be used for bonding in the manufacturing process.
That is, when assembling a liquid crystal module composed of a liquid crystal panel, a retardation plate, a polarizing plate, a light diffusing plate, etc., it is easy to attach a glass substrate or plastic substrate to a retardation plate, a polarizing plate, a light diffusing plate, etc. It is effective for improving productivity because it can be re-applied.

  The pressure-sensitive adhesive sheet of the present invention is also suitable as a back grind tape. The back grind tape is a tape that protects the wafer surface during back grind (grinding of the back surface of the wafer) after an electronic circuit is formed on the semiconductor wafer. A back grind tape is applied to the circuit surface to prevent damage to the circuit surface and contamination of the wafer surface due to ingress of grinding water and grinding debris. The pressure-sensitive adhesive sheet of the present invention is excellent in adhesiveness and hardly deviates within the sticking surface of the stuck adherend, but has a low peel strength and can be easily peeled off. When polyolefins are used as the base material, a separator is unnecessary and contamination such as silicone does not occur. Moreover, since peeling electrification is suppressed, there is little risk of damaging the circuit.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.
Hereinafter, propylene oxide is abbreviated as PO, dibutyltin dilaurate is abbreviated as DBTDL, and 3-isocyanatopropyltrimethoxysilane (isocyanate group (NCO) content: 17.87% by mass) is abbreviated as TMS. Pure water was used as the water. As the stainless steel plate, a SUS-304 alloy plate defined in JIS was used. The bright annealed surface of this stainless steel plate is almost smooth and glossy.

(Reference Production Example 1: Production of double metal cyanide complex catalyst)
Zinc hexacyanocobaltate (hereinafter referred to as TBA-DMC catalyst) having tert-butyl alcohol as an organic ligand was produced by the following method. The polyol X in this example is a polyol having a number average molecular weight (Mn1) of 1000, obtained by addition polymerization of propylene oxide to dipropylene glycol.
First, an aqueous solution consisting of 10.2 g of zinc chloride and 10 g of water was placed in a 500 ml flask, and while maintaining the aqueous solution at 40 ° C., stirring at 300 rpm (300 rpm), 4.2 g An aqueous solution composed of potassium hexacyanocobaltate (K ₃ [Co (CN)] ₆ ) and 75 g of water was added dropwise over 30 minutes. After completion of the dropwise addition, the mixture was further stirred for 30 minutes. Thereafter, a mixture of 40 g of ethylene glycol mono-tert-butyl ether (hereinafter abbreviated as EGMTBE), 40 g of tert-butyl alcohol (hereinafter abbreviated as TBA), 80 g of water, and 0.6 g of polyol X was obtained. The mixture was added to the mixture and stirred at 40 ° C. for 30 minutes and further at 60 ° C. for 60 minutes. The obtained reaction mixture was filtered for 50 minutes under pressure (0.25 MPa) using a circular filter plate having a diameter of 125 mm and a quantitative filter paper for fine particles (No. 5C manufactured by ADVANTEC Co.) to obtain a solid. separated.
Next, a mixture comprising 18 g of EGMTBE, 18 g of TBA, and 84 g of water was added to the cake containing the double metal cyanide complex and stirred for 30 minutes, followed by pressure filtration (filtration time: 15 minutes). It was. To the cake containing the double metal cyanide complex obtained by filtration, a mixture of 54 g EGMTBE, 54 g TBA, and 12 g water was added and stirred for 30 minutes, and the double metal cyanide having an organic ligand was stirred. A slurry of EGMTBE / TBA containing the complex was obtained. This slurry was used as a TBA-DMC catalyst.
About 5 g of this slurry was weighed into a flask, dried roughly with a nitrogen stream, and then dried under reduced pressure at 80 ° C. for 4 hours. As a result of weighing the obtained solid, it was found that the concentration of the double metal cyanide complex contained in the slurry was 4.70% by mass.

(Production Example 1: Production of silyl group-containing polymer (S1-1))
800 g of polyoxypropylene diol (hydroxyl equivalent Mw = 1000) as an initiator and a TBA-DMC catalyst as a polymerization catalyst were charged into a 10 L stainless steel pressure-resistant reactor equipped with a stirrer. The amount of TBA-DMC catalyst used was 50 ppm with respect to the finished mass.
After the inside of the reactor was purged with nitrogen, the temperature was raised to 140 ° C., and 80 g of PO was charged into the reactor with stirring to react. This is a process for initially supplying a small amount of PO to activate the TBA-DMC catalyst.
Next, after the pressure in the reactor is lowered, 7120 g of PO is supplied with stirring, and the polymerization reaction is allowed to proceed by stirring for 11 hours while maintaining the temperature in the reactor at 140 ° C. and the stirring speed at 500 rpm. It was. In this way, polyol A was obtained. The average hydroxyl value of polyol A was 11 mgKOH / g.
To a four-necked flask equipped with a stirrer, reflux condenser, nitrogen inlet tube, thermometer, and dropping funnel, 761.6 g of the polyol A obtained above and 31.8 g of TMS as isocyanate silanes were added and urethanized. DBTDL was added as a catalyst. The amount of DBTDL used was an amount corresponding to 50 ppm with respect to the total amount of polyol A and TMS. And it heated up gradually to 80 degreeC, and it reacted until the NCO peak disappeared by IR, and obtained the silyl group containing polymer (S1-1). The hydrolyzable silyl group introduction ratio was 100%.

(Production Example 2: Production of acrylic polymer (P-1))
A reactor equipped with a stirrer, a reflux condenser, a sequential dropping device, and a thermometer, 20% by mass of a monomer mixture consisting of 95 parts by mass of n-butyl acrylate and 5 parts by mass of acrylic acid, and ethyl acetate 40 A mass part and 0.01 part by mass of azobisisobutyronitrile as a polymerization initiator were added and heated, and polymerization was carried out at a reflux temperature for about 20 minutes. Next, 80% by mass of the remaining amount of the monomer mixture under reflux temperature conditions and a polymerization initiator solution consisting of 20 parts of ethyl acetate and 0.1 part by mass of azobisisobutyronitrile are successively added dropwise over about 90 minutes, Furthermore, 10 parts of ethyl acetate and 0.2 part by mass of azobisisobutyronitrile were successively added dropwise for 40 minutes, and the polymerization reaction was further carried out for 120 minutes. After completion of the reaction, the reaction mixture was diluted with toluene and adjusted to a solid content of 40% by mass to obtain an acrylate polymer solution (P-1) having a viscosity of 7500 mPa · s and a mass average molecular weight of 180,000.

Example 1
95 parts by mass of the silyl group-containing polymer (S1-1) and 5 parts by mass of the acrylic polymer (P-1) were used. 100 parts by mass of these polymer mixtures, 0.03 parts by mass of water as a curing agent, and 1 part by mass of DBTDL as a curing catalyst were mixed to produce a curable composition.
The obtained curable composition was coated on a PET film (base material) having a thickness of 100 μm that had not been surface-treated so that the film thickness after drying would be 50 μm, and was 100 ° C. in a circulation oven. For 5 minutes. Then, after curing at 23 ° C. for one week, it was left at 23 ° C. and a relative humidity of 65% for 2 hours to form an adhesive layer to obtain an adhesive sheet.

(Examples 2 to 4 and Comparative Examples 1 and 2)
In Example 1, a curable composition was produced by changing the mixing ratio of the silyl group-containing polymer (S1-1) and the acrylic polymer (P-1) as shown in Table 1, and the same as in Example 1. Thus, an adhesive sheet was obtained.

(Evaluation methods)
About the obtained adhesive sheet, the following method measured the peel strength, and evaluated adhesiveness and wettability. The results are shown in Table 1. In the table, the mixing ratio is a mass ratio.
[Peel strength]
At room temperature, the obtained pressure-sensitive adhesive sheet was attached to a stainless steel plate having a thickness of 1.5 mm that had been bright-annealed and pressure-bonded with a 2 kg rubber roll. After 30 minutes at room temperature, 24 hours at room temperature (1 day), 168 hours at 60 ° C. (7 days), 336 hours at 60 ° C. (14 days), 504 hours at 60 ° C. (21 days), 672 hours at 60 ° C. After 28 days, the peel strength (unit: N / 25 mm, 180 degree peel, tensile speed 300 mm / min) was measured using a tensile tester (Orientec, RTE-1210) specified in JIS B 7721. did. The smaller this value, the lower the adhesive strength, the easier it is to peel off, and the better the removability. The value of the peel strength after 30 minutes at room temperature corresponds to the “peel strength” in the present invention. “C” in the table indicates that cohesive failure occurred.
The table also shows the ratio of [peel strength after 672 hours (28 days) at 60 ° C.] to [peel strength after 30 minutes at room temperature] (60 ° C., 4 weeks / room temperature 30 minutes). To do.

[durability]
The change rate [unit:%] of the peel strength after 672 hours (28 days) at 60 ° C. with respect to the peel strength after 30 minutes at room temperature was determined by the following formula.
Peel strength change rate (%) = [Peel strength after 672 hours (28 days) at 60 ° C.−Peel strength after 30 minutes at room temperature] ÷ [Peel strength after 30 minutes at room temperature] × 100
When the value of the change rate of the peel strength was −0 to −20% or +0 to 100%, the durability was evaluated as “good”.
Normally, when the pressure-sensitive adhesive is heated, it softens and increases the adhesion area. Therefore, even if the pressure-sensitive adhesive itself does not change, the peel strength tends to be higher than the initial value.

[Adhesion]
After the adhesive sheet was attached to a bright annealed stainless steel plate, each sample was allowed to stand for 30 minutes at 23 ° C. and a relative humidity of 65%, and then peeled to visually evaluate the substrate adhesion. In the visual evaluation, the case where there was no glue transfer to the stainless steel plate was evaluated as ◯ (good), the case where there was a partial transfer was evaluated as △ (slightly good), and the case where it was completely transferred was evaluated as x (bad).
The fact that there is no glue transfer to the stainless steel plate means that the adhesion between the adhesive sheet substrate and the adhesive layer is good, and the adhesive layer and the stainless steel plate as the adherend are easily peeled off. Means hard to peel off.

[Wettability]
The adhesive sheet was placed on a stainless steel plate that had been bright annealed at 23 ° C. with the adhesive surface of 25 mm × 100 mm facing down, and the wet area after standing for 3 minutes was visually evaluated. "O" when the entire adhesive surface is wet, "N1" when approximately 2/3 of the entire surface is wet, "N2" when approximately 1/2 of the entire surface is wet, "Wet surface" Was 1/3 or less of the entire surface, was designated as “N3”, and N1 to 3 were ineligible.

  From the results of Table 1, the pressure-sensitive adhesives obtained by curing the curable compositions of Examples 1 to 4 have low adhesive strength and good removability, while the time-dependent increase in adhesive strength is small, and the time Even with this, good adhesion to the adherend was maintained. Moreover, the adhesiveness to a base material was favorable, and the wettability and durability to a to-be-adhered body were also favorable.

Claims (9)

  Curability containing a silyl group-containing polymer (S) having a polyether chain, a polyester chain, and / or a polycarbonate chain in the main chain, and a hydrolyzable silyl group at the molecular end, and an acrylic polymer (P) An adhesive obtained by curing the composition.   The silyl group-containing polymer (S) introduces a hydrolyzable silyl group into the terminal of one or more polyol compounds selected from the group consisting of polyether polyol, polyester polyol, polycarbonate polyol, and polyether polyester polyol. The pressure-sensitive adhesive body according to claim 1, which is a silyl group-containing polymer (S1) obtained in the above manner.   The silyl group-containing polymer (S) is obtained by reacting one or more polyol compounds selected from the group consisting of polyether polyol, polyester polyol, polycarbonate polyol, and polyether polyester polyol with a polyisocyanate compound. The pressure-sensitive adhesive according to claim 1, which is a silyl group-containing polymer (S2) obtained by introducing a hydrolyzable silyl group into the terminal of the polyurethane prepolymer.   The silyl group-containing polymer (S) is obtained by reacting one or more polyol compounds selected from the group consisting of polyether polyol, polyester polyol, polycarbonate polyol, and polyether polyester polyol with a polyisocyanate compound. The silyl group-containing polymer (S3) obtained by introducing a hydrolyzable silyl group into a molecular terminal of a polyurethane polymer obtained by further subjecting the polyurethane prepolymer to a chain extension reaction using a chain extender. 1. The pressure-sensitive adhesive body according to 1.   The pressure-sensitive adhesive body according to any one of claims 1 to 4, wherein the acrylic polymer (P) has a number average molecular weight of 10,000 to 1,000,000.   The hydrolyzable silyl group of the silyl group-containing polymer (S) is introduced using one or more silane compounds selected from isocyanate silanes, aminosilanes, mercaptosilanes, epoxysilanes, and hydrosilanes. Moreover, the adhesive body in any one of Claims 1-5.   The pressure-sensitive adhesive according to claim 1, wherein the hydrolyzable silyl group is a trialkoxysilyl group.   The pressure-sensitive adhesive body according to any one of claims 1 to 7, which has a peel adhesive strength of 8 N / 25 mm or less.   A pressure-sensitive adhesive sheet comprising a base material layer and at least one pressure-sensitive adhesive layer, wherein the pressure-sensitive adhesive layer is made of the pressure-sensitive adhesive according to claim 1.