JPH1036802A - Pressure-sensitive adhesive and adhesive sheet made therefrom - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a pressure-sensitive adhesive excellent in holding power at high temperature, adhesiveness near room temperature and applicability, and having long pot life by blending a specified acrylic polymer with an aminosilane coupling agent in a specified amount. SOLUTION: This adhesive is obtained by blending 100 pts.wt. acrylic polymer made from 59-94wt.% acrylic monomer represented by the formula CH2 =C(R<1> ) COOR<2> (wherein R<1> is H or CH3 ; and R<2> is a 4-14C alkyl), 5-40wt.% N,N- disubstituted (meth)acrylamide represented by the formula CH2 =C(R<3> )CONR<4> R<5> (wherein R<3> is R<1> ; and R<4> and R<5> are each alkyl or an organic group which may be combined together to form a heterocyclic ring with nitrogen atoms) and 1-10wt.% monomer containing an acidic group (e.g. acrylic acid) with 0.01-3 pts.wt. aminosilane coupling agent [e.g. N-β-(aminoethyl)γ- aminopropyltrimethoxysilane].

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure-sensitive adhesive containing an acrylic polymer as a main component and adhesive sheets in the form of a sheet or tape.

[0002]

2. Description of the Related Art A so-called pressure-sensitive adhesive tape formed of a pressure-sensitive adhesive alone or together with a support in the form of a sheet or tape in place of a liquid type adhesive for the purpose of simplifying the bonding operation and improving safety and health. Adhesive work using is widely practiced. As the use of adhesive tapes expands, the required properties also become more diverse, such as the holding force under high temperature conditions (adhesive tape is applied to an adherend, and when a constant static load is applied in the length direction, the adhesive Force to withstand slippage)
Is a seed. Usually, the most commonly used method for improving the holding power of a pressure-sensitive adhesive tape using a pressure-sensitive adhesive made of an acrylic polymer under high-temperature conditions (hereinafter, referred to as heat-resistant holding property) is as follows: In this method, a crosslinking treatment is applied to the pressure-sensitive adhesive to increase the molecular weight, thereby suppressing fluidization of the pressure-sensitive adhesive. However, when the degree of crosslinking of the pressure-sensitive adhesive is increased in order to improve the heat-resistant holding property, the adhesive strength in a low-temperature region below room temperature tends to decrease. Have difficulty.

On the other hand, as a means for improving the adhesive properties under high temperature and high humidity without substantially lowering the properties of a pressure-sensitive adhesive having suitable adhesive properties at room temperature (normal state), an acrylic polymer is used. A pressure-sensitive adhesive composition in which at least one selected from vinyl silane, epoxy silane, and methacryl silane is blended with the pressure-sensitive adhesive is disclosed. However, when a so-called silane coupling agent described in JP-B-62-30233 is added to a pressure-sensitive adhesive made of an acrylic polymer, the pressure-sensitive adhesive becomes There is a problem of coatability such that the viscosity may be remarkably increased, making it difficult to apply the pressure-sensitive adhesive in a sheet or tape form.

[0004] In view of the above-mentioned conventional circumstances, the present invention can achieve both heat resistance retention and good adhesiveness at around room temperature and, when a silane coupling agent is added to a pressure-sensitive adhesive, a pressure-sensitive adhesive. The viscosity of the adhesive increases significantly,
It is an object of the present invention to provide a pressure-sensitive adhesive having excellent coatability and an adhesive sheet thereof without making it difficult to apply.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, as a monomer component constituting an acrylic polymer, N-N-di-substituted (meth)
Addition of acrylamide, furthermore, by blending a silane coupling agent having an amino group to the acrylic polymer, it was found that a pressure-sensitive adhesive that is less likely to increase in viscosity due to the addition of the silane coupling agent was obtained. The pressure-sensitive adhesive was found not only to be excellent in heat retention, but also to have no decrease in adhesive strength near room temperature due to the addition of a crosslinking agent, and completed the present invention.

That is, the present invention relates to the following a to c components: a) General formula (1); CH ₂ ＣC (R ¹ ) COOR ² (where R ¹ is a hydrogen or methyl group, and R ² is a carbon number 4-1
Acrylic monomer 5 represented by the formula (4):
9 to 94% by weight b) General formula (2); CH ₂ ＣC (R ³ ) CONR ⁴ R ⁵
(Wherein R ³ is hydrogen or a methyl group, R ⁴ and R ⁵ are alkyl groups or an organic group in which both are bonded to each other and form an heterocyclic ring with an N atom).・ N-
5 to 40% by weight of di-substituted (meth) acrylamide c) 100 parts by weight of an acrylic polymer composed of 1 to 10% by weight of a monomer containing an acidic group, and d) a silane coupling agent having an amino group .01
To 3 parts by weight, and an adhesive sheet having a layer made of the above-mentioned pressure-sensitive adhesive on one or both sides of the support. .

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The acrylic monomer as the component a in the present invention is, for example, a compound in which R ² in the general formula (1) is a butyl group, an isobutyl group, an isoamyl group, a hexyl group,
Heptyl group, 2-ethylhexyl group, isooctyl group,
An acrylic acid or methacrylic acid ester comprising an alkyl group having 4 to 14 carbon atoms, such as an isononyl group and an isodecyl group, is exemplified. If the carbon number of R ² is less than 4, the wettability of the pressure-sensitive adhesive is lowered to deteriorate the initial adhesiveness, and if it exceeds 14, there is a problem that the adhesive strength is inferior.

The acrylic monomer as the component (a) is as follows:
59 to 94% by weight of the total monomer, preferably 65 to 90%
One or more of them are used in the range of weight%. If it is less than 59% by weight, the performance as an acrylic pressure-sensitive adhesive cannot be exhibited, and if it exceeds 94% by weight, the b and c components described later are insufficient, so that the adhesive properties and coating properties are excellent. No pressure sensitive adhesive can be obtained.

In the present invention, the N-N-disubstituted (meth) acrylamide as the component (b) can be used as a pressure-sensitive adhesive when a silane coupling agent having an amino group of the component (d) described below is added to the acrylic polymer. This is to prevent the viscosity of the pressure-sensitive adhesive from significantly increasing or gelling, thereby preventing the applicability of the pressure-sensitive adhesive to the support from deteriorating. In the present invention, the copolymer is copolymerized with an acrylic polymer. It is an essential monomer component that needs to be added.

[0010] The N · N-di-substituted (meth) acrylamide, R ⁴ in the general formula (2), and (meth) acrylamide acyclic which is R ⁵ are both an alkyl group, the R ^4,
Cyclic (meth) acrylamide which forms a heterocyclic ring by combining R ⁵ and this and an N atom is included, and either one or both of them are used depending on the purpose of use.

The acyclic (meth) acrylamide includes N.N-dimethyl (meth) acrylamide, N
-N-diethyl (meth) acrylamide, N-N-dibutyl (meth) acrylamide and the like. Examples of the cyclic (meth) acrylamide include N- (meth) acryloylmorpholine, N- (meth) acryloylpyrrolidone, N- (meth) acryloylpiperidine, N- (meth) acryloylpyrrolidine, N- (meth) acryloyl- 4-piperidone and the like.

One or more of the NN-disubstituted (meth) acrylamides as the component b may be used in an amount of 5 to 40% by weight, preferably 10 to 35% by weight based on the total amount of the monomers. Is used. If the amount is less than 5% by weight, the increase in viscosity and gelation of the pressure-sensitive adhesive when the silane coupling agent is blended with the acrylic polymer cannot be sufficiently suppressed. If it exceeds 40% by weight, the modulus of elasticity of the pressure-sensitive adhesive increases, and the wettability of the pressure-sensitive adhesive decreases.

The monomer containing an acidic group as the component c in the present invention includes, for example, carboxyl group-containing monomers such as acrylic acid, methacrylic acid, itaconic acid, maleic acid and crotonic acid, as well as 2-acrylamide- Sulfonic acid group-containing monomers such as 2-methylpropanesulfonic acid;
There are phosphoric acid group-containing monomers such as hydroxyethyl acryloyl phosphate and 2-hydroxypropyl acryloyl phosphate.

One or more of the monomers containing an acidic group as the component c are used in an amount of 1 to 10% by weight, preferably 2 to 8% by weight of the total amount of the monomers.
If the content is less than 1% by weight, the heat resistance is reduced, and 10% by weight.
If it exceeds, the adhesive strength near room temperature decreases, and in any case, it is difficult to exhibit good adhesive properties.

The acrylic polymer of the present invention has the above-mentioned a to
c monomer mixture consisting of three components, by a conventional method, a solution polymerization method, an emulsion polymerization method, a bulk polymerization method, can be obtained by copolymerization by a method such as a suspension polymerization method, in the bulk polymerization method, A polymerization method by ultraviolet irradiation is preferably employed.

As the polymerization initiator used in the polymerization, organic peroxides such as benzoyl peroxide, lauroyl peroxide and cumene peroxide;
Azo compounds such as 2'-azobisisobutyronitrile and 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2-dimethoxy-2-phenylacetophenone and 2,2-diethoxyacetophenone Benzoin ether compounds such as benzoin ethyl ether and benzoin isopropyl ether; and benzophenone compounds such as benzophenone and benzoyl benzoic acid.

In the present invention, the silane coupling agent as the d component blended in the acrylic polymer composed of the three components a to c is used to prevent the adhesive force of the pressure-sensitive adhesive from decreasing at around room temperature. Is what is done. The silane coupling agent of the above component d used in the present invention needs to have an amino group, and by using such a specific silane coupling agent, N.
When a silane coupling agent is blended with an acrylic polymer containing N-disubstituted (meth) acrylamide as a copolymer component, an increase in viscosity and gelation of the pressure-sensitive adhesive can be prevented.

Examples of the silane coupling agent having an amino group include N-β- (aminoethyl) γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) γ-aminopropyltriethoxysilane, and N-β- (aminoethyl) γ-aminopropyltriethoxysilane. β
-(Aminoethyl) γ-aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, N
-Phenyl-γ-aminopropyltrimethoxysilane,
γ-anilinopropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, aminosilane, N-β
-(N-vinylbenzylaminoethyl) γ-aminopropyltriethoxysilane hydrochloride, octadecyldimethyl [3- (trimethoxysilyl) propyl] ammonium chloride and the like.

The silane coupling agent as the component d is used in an amount of 0.0 to 100 parts by weight of the acrylic polymer.
1 to 3 parts by weight, preferably 0.05 to 1 part by weight. If the amount is less than 0.01 part by weight, the adhesive strength near room temperature is insufficient, and if it is added more than 3 parts by weight, no effect is observed in further improving the adhesive force near room temperature.

The pressure-sensitive adhesive of the present invention may optionally contain a crosslinking agent. The type of the crosslinking agent is not particularly limited, and for example, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, 1,2-ethylene glycol di (meth) acrylate, 1,6-hexane Multifunctional (meth) such as diol di (meth) acrylate and 1,12-dodecanediol di (meth) acrylate
Acrylate, tolylene diisocyanate adduct of trimethylolpropane, ethylene diisocyanate, butylene diisocyanate, hexamethylene diisocyanate, cyclopentylene diisocyanate, cyclohexylene diisocyanate, isophorone diisocyanate, 2,4-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate And polyfunctional isocyanate compounds such as xylylene diisocyanate.

The amount of the crosslinking agent is not particularly limited, but is preferably in the range of 0.01 to 10 parts by weight with respect to 100 parts by weight of the acrylic polymer. Is desirable.

The pressure-sensitive adhesive of the present invention is prepared by mixing a predetermined amount of a silane coupling agent of component d with an acrylic polymer composed of components a to c, mixing a crosslinking agent if necessary, and then stirring. It is produced by doing. The pressure-sensitive adhesive of the present invention may further contain additives such as fillers such as glass fibers and metal powders, pigments and colorants, if necessary.

The adhesive sheets of the present invention are formed by providing a layer comprising the above-mentioned pressure-sensitive adhesive at a desired thickness on one side or both sides of a support to form a sheet or tape. is there. As the support, a plastic film, paper, non-woven fabric, rubber-based or synthetic resin-based foam sheet, metal foil, or the like can be used, and one or both of which are subjected to a peeling treatment or an adhesion treatment is used. You may.

[0024]

EXAMPLES The present invention will be described below with reference to specific examples, but the present invention is not limited to these examples. In the following, “parts” means “parts by weight”.

(Example 1) A reaction vessel equipped with a cooling pipe, a nitrogen introduction pipe, a thermometer, an ultraviolet irradiation device, and a stirring device was charged with 75 parts of isononyl acrylate and 2 parts of diethylacrylamide.
0 parts, 6 parts of acrylic acid, and 0.07 part of 2,2-dimethoxy-2-phenylacetophenone as a polymerization initiator were added, and the mixture was polymerized by irradiation with ultraviolet rays to obtain a polymer / monomer mixture having a conversion of 15%. To 100 parts of the polymer / monomer mixture, 0.1 part of trimethylolpropane triacrylate and 0.1 part of N-β- (aminoethyl) γ-aminopropyltrimethoxysilane are added, mixed and syrup (pressure-sensitive adhesive). Agent solution). The syrup was applied on a polyester film having a thickness of 25 μm and irradiated with ultraviolet rays to produce an adhesive tape having a layer of a pressure-sensitive adhesive having a thickness of 50 μm.

Example 2 65 parts of 2-ethylhexyl acrylate, 35 parts of acryloyl morpholine, 3 parts of acrylic acid, 2,2 as a polymerization initiator were placed in a reaction vessel equipped with a cooling pipe, a nitrogen introducing pipe, a thermometer, and a stirrer. 0.14 parts of '-azobisisobutyronitrile and 100 parts of ethyl acetate were added and reacted at 60 ° C for 12 hours to obtain a polymer solution.
To this polymer solution, 1.0 part of tolylene diisocyanate adduct of trimethylolpropane (trade name: Coronate L, manufactured by Nippon Polyurethane Co., Ltd.) and 100 parts of N-β- (aminoethyl) γ- 1.0 part of aminopropyltrimethoxysilane was added and mixed to obtain a syrup. The syrup is applied on a polyester film having a thickness of 25 μm and dried to obtain a film having a thickness of 5 μm.
An adhesive tape having a 0 μm layer of pressure sensitive adhesive was prepared.

Example 3 A polymer having a polymerization rate of 15% was produced in the same manner as in Example 1 except that the monomer composition was changed to 85 parts of isononyl acrylate, 10 parts of diethylacrylamide, and 8 parts of acrylic acid. / Monomer mixture was obtained.
To 100 parts of this polymer / monomer mixture, 0.1 part of trimethylolpropane triacrylate and 0.5 part of N-β- (aminoethyl) γ-aminopropyltrimethoxysilane are added, mixed and syrup (pressure-sensitive adhesive). Agent solution). The syrup was applied on a polyester film having a thickness of 25 μm and irradiated with ultraviolet rays to produce an adhesive tape having a layer of a pressure-sensitive adhesive having a thickness of 50 μm.

Comparative Example 1 Except that the monomer composition was changed to 90 parts of isononyl acrylate and 8 parts of acrylic acid,
Polymerization was carried out in the same manner as in Example 1 to obtain a polymer / monomer mixture having a conversion of 15%. To 100 parts of this polymer / monomer mixture, 0.1 part of trimethylolpropane triacrylate and 1.0 part of N-β- (aminoethyl) γ-aminopropyltrimethoxysilane are added, mixed and syrup (pressure-sensitive adhesive). Agent solution). An attempt was made to apply this syrup on a 25 μm thick polyester film, but the syrup was too viscous to be applied on the film.

Comparative Example 2 A polymer solution was obtained by polymerization in the same manner as in Example 2 except that the monomer composition was changed to 90 parts of 2-ethylhexyl acrylate and 8 parts of acrylic acid. To this polymer solution, 1.0 part of Coronate L and 1.0 part of N-β- (aminoethyl) γ-aminopropyltrimethoxysilane with respect to 100 parts of polymer solid content are added and mixed to obtain a syrup. Was. An attempt was made to apply this syrup on a 25 μm thick polyester film, but the syrup was too viscous to be applied on the film.

Comparative Example 3 The same polymer as in Example 1
To 100 parts of the monomer mixture, 0.1 part of trimethylolpropane triacrylate was added and mixed to obtain a syrup. The syrup is applied on a polyester film having a thickness of 25 μm, and irradiated with ultraviolet rays, so that a
An adhesive tape having m layers of pressure sensitive adhesive was prepared.

Comparative Example 4 In the same polymer solution as in Example 2, Coronate L was added to 100 parts of the polymer solid content.
1.0 part was added and mixed to obtain a syrup. The syrup was applied on a 25 μm-thick polyester film and dried to prepare an adhesive tape having a 50 μm-thick pressure-sensitive adhesive layer.

Comparative Example 5 Polymerization was carried out in the same manner as in Example 1 except that the monomer composition was changed to 75 parts of isononyl acrylate and 25 parts of diethylacrylamide.
A 5% polymer / monomer mixture was obtained. To 100 parts of this polymer / monomer mixture, 0.1 part of trimethylolpropane triacrylate, N-β- (aminoethyl)
1.0 part of γ-aminopropyltrimethoxysilane was added and mixed to obtain a syrup. Syrup thickness 25μm
Was applied onto a polyester film of Example 1 and irradiated with ultraviolet rays to produce an adhesive tape having a layer of a pressure-sensitive adhesive having a thickness of 50 μm.

(Comparative Example 6) The monomer composition was as follows: 2-ethylhexyl acrylate 65 parts, acryloyl morpholine 3
Except having changed to 5 parts, it superposed | polymerized similarly to Example 2, and
A polymer solution was obtained. In this polymer solution, 1.0 part of Coronate L and 100 parts of N-β
1.0 part of-(aminoethyl) γ-aminopropyltrimethoxysilane was added and mixed to obtain a syrup. The syrup was applied on a 25 μm-thick polyester film and dried to prepare an adhesive tape having a 50 μm-thick pressure-sensitive adhesive layer.

Comparative Example 7 The same polymer as in Example 1 was used.
To 100 parts of the monomer mixture, 0.1 part of trimethylolpropane triacrylate and 0.1 part of γ-glycidoxypropylmethoxysilane were added and mixed to obtain a syrup. An attempt was made to apply this syrup on a 25 μm thick polyester film, but the syrup was too viscous to be applied on the film.

Comparative Example 8 In the same polymer solution as in Example 2, Coronate L was added to 100 parts of the polymer solid content.
1.0 part and 1.0 part of γ-glycidoxypropylmethoxysilane were added and mixed to obtain a syrup. An attempt was made to apply this syrup on a 25 μm thick polyester film, but the syrup was too viscous to be applied on the film.

The pressure-sensitive adhesives and adhesive tapes obtained in Examples 1 to 3 and Comparative Examples 1 to 8 were evaluated as follows.

[Viscosity] The viscosity of the syrup (pressure-sensitive adhesive solution) was measured using a B-type viscometer. (Measurement temperature 30
℃)

[Solvent Insolubles] An amount of the pressure-sensitive adhesive of about 0.1 g was collected from the adhesive tape and precisely weighed. This is 50m
The mixture was placed in a glass bottle containing 1 l of ethyl acetate, subjected to an extraction treatment using an ultrasonic cleaner for 20 minutes, allowed to stand for 10 minutes, and then subjected to an extraction treatment for another 20 minutes. The residue after the extraction treatment was filtered through a nylon woven fabric (80 mesh), and the residue remaining on the nylon woven fabric was dried in an atmosphere at 130 ° C. for 2 hours, and the dry weight of the residue was measured. The ratio of the dry weight to the weight of the collected sample was defined as the solvent-insoluble matter (% by weight).

[Peeling Adhesion] A 2 kg roller was placed on a stainless steel plate sanded with sandpaper (# 280) using an adhesive tape of 20 mm × 100 mm as an adherend.
Crimping by reciprocating and leaving for 20 minutes, 23 ° C, 65
The 180 ° peel adhesion was measured in an atmosphere of% RH at a tensile speed of 300 mm / min.

[Holding force] An adhesive tape having a width of 10 mm was adhered as an adherend to a stainless steel plate sanded with sandpaper (# 280) with an adhesive area of 10 mm × 20 mm. After standing for a minute, the stainless steel plate is hung down, a 500 g uniform load is applied to the free end of the adhesive tape, and the falling time (min) of the adhesive tape at 80 ° C. and the displacement (mm) after 240 minutes are measured. It was measured.

The results are shown in Table 1.

[0042]

[Table 1]

As is evident from Table 1, Examples 1 to 3 of the present invention in which a silane coupling agent having an amino group was blended with an acrylic polymer having N, N-disubstituted (meth) acrylamide as a copolymer component. The pressure-sensitive adhesive of No. 3 is Comparative Example 1,
No increase in viscosity of the pressure-sensitive adhesive as observed in 2, 7, and 8 is observed. Further, it can be seen that the adhesive tapes of the examples have a high adhesive strength at around room temperature and also have good holding power characteristics under high temperature conditions.

[0044]

According to the pressure-sensitive adhesive of the present invention having the above-described structure, it is possible to suppress an increase in the viscosity of the pressure-sensitive adhesive by adding a silane coupling agent to the pressure-sensitive adhesive. it can. Therefore, the pressure-sensitive adhesive of the present invention is excellent in coatability as compared with the conventional pressure-sensitive adhesive, and has a longer pot life (pot life) of the pressure-sensitive adhesive, so that the pressure-sensitive adhesive can be used industrially. Very useful pressure sensitive adhesives can be provided. Further, the adhesive tape of the present invention using the above-mentioned pressure-sensitive adhesive can achieve both a holding force characteristic under a high temperature condition and a high adhesive force at around room temperature. It is possible to improve the required reliability of the adhesive property in a wide temperature range from a high temperature to a low temperature.

Claims (2)

[Claims] 1. The following a to c components: a) General formula (1); CH ₂ ＣC (R ¹ ) COOR ² (wherein R ¹ is a hydrogen or methyl group, and R ² is a carbon number of 4 to 4) 1
Acrylic monomer 5 represented by the formula (4):
9 to 94% by weight b) General formula (2); CH ₂ ＣC (R ³ ) CONR ⁴ R ⁵
(Wherein R ³ is hydrogen or a methyl group, R ⁴ and R ⁵ are alkyl groups or an organic group in which both are bonded to each other and form an heterocyclic ring with an N atom).・ N-
5 to 40% by weight of di-substituted (meth) acrylamide c) 100 parts by weight of an acrylic polymer composed of 1 to 10% by weight of a monomer containing an acidic group, and d) a silane coupling agent having an amino group .01
A pressure-sensitive adhesive, characterized in that it is mixed in an amount of up to 3 parts by weight. 2. An adhesive sheet having a layer comprising the pressure-sensitive adhesive according to claim 1 on one or both sides of a support.