JPH04314775A - Pressure-sensitive adhesive - Google Patents

Abstract

PURPOSE:To provide a pressure-sensitive adhesive which can be satisfactorily applied to a vulcanized rubber molding even when the molding is not subjected to conventional treatment such as buffing or priming. CONSTITUTION:An adhesive composition is prepared by mixing a halogenated butyl rubber as a base with a bivalent amphoteric metal oxide, a metal chloride, an organic ultraaccelerator and an aromatic sec. amine antioxidant in a specified ratio.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is applicable to natural rubber, chloroprene rubber, EPT (ethylene-propylene terpolymer)
This invention relates to a pressure-sensitive adhesive used for bonding vulcanized rubber molded products made of rubber or the like.

0002

BACKGROUND OF THE INVENTION Vulcanized rubber molded products of this type are widely used as parts for automobiles, home appliances, OA equipment, and various industrial products.

However, these rubber molded products contain a large number of adhesion inhibiting substances such as various fillers, vulcanizing agents, and oil components as a compound, and in the process of vulcanizing the rubber molded products, the mold from the press mold is removed. Because a mold release agent such as silicone oil is used to improve separation, the adhesiveness of the molded product surface is poor.

Moreover, these vulcanized rubber molded products have high elasticity, so when they are attached to a curved surface, they are adhesively fixed under stress due to the elastic action. Due to this and the poor adhesiveness of the surface of the molded product, there was a problem that the molded product easily peeled off after being adhesively fixed.

For this reason, in the past, the surface of the vulcanized rubber molded product was first buffed, then washed with a solvent and coated with a primer, and then a film-like pressure-sensitive adhesive was bonded thereon. Therefore, methods such as adhesive fixation to other adherends have been adopted.

[0006]

[Problems to be Solved by the Invention] However, the above-mentioned processes such as buffing and primer application require a lot of man-hours, and there is a risk that the buffing powder and solvent will scatter, worsening the working environment. However, there was a problem in that the degree of buffing tends to vary, and this also causes variations in adhesive strength.

In view of the above-mentioned circumstances, the present invention has developed a pressure-sensitive material that can obtain sufficient adhesive strength without performing conventional treatments such as buffing and primer coating on vulcanized rubber molded products. The purpose is to provide adhesives.

[0008]

[Means for Solving the Problems] As a result of intensive studies to achieve the above object, the present inventors have found that they use a specific polymer as the main component of an adhesive, and that a method for crosslinking this polymer is used. I learned that a pressure-sensitive adhesive containing a specific cross-linking agent can sufficiently bond vulcanized rubber molded products without the need for conventional treatments such as buffing or primer application. The present invention has now been completed.

That is, the present invention has halogenated butyl rubber as a main component, and per 100 parts by weight of this rubbery polymer, 0.2 to 20 parts by weight of a divalent amphoteric metal oxide and 0.1 to 0.1 to 20 parts by weight of a metal chloride. 10 parts by weight and 0 organic super vulcanization accelerator
．． 1 to 10 parts by weight, aromatic secondary amine antioxidant 1
The present invention relates to a pressure-sensitive adhesive using a rubber-based pressure-sensitive adhesive composition containing 0 parts by weight or less.

0010

Structure and operation of the invention The rubbery polymer in the present invention has a high affinity with vulcanized rubber molded products, and is a polymer that exhibits selective wettability by eliminating adhesion inhibiting substances in the surface layer. Halogenated butyl rubber, which is a copolymer of butyl rubber with 1 to 3% by weight of isoprene, is brominated or chlorinated. The molecular weight of this rubbery polymer is preferably 200,000 to 1,000,000 in weight average molecular weight.

The present invention is characterized by having such a rubbery polymer as a main component and blending it with a specific crosslinking agent, thereby achieving a pressure-sensitive adhesive that is insufficient when using the above-mentioned polymer alone. The desired high cohesive force is imparted, and strong adhesive strength capable of withstanding the repulsive force of the vulcanized rubber molded product is obtained.

The specific crosslinking agent used here consists of four components: a divalent amphoteric metal oxide, a metal chloride, an organic supervulcanization accelerator, and an aromatic secondary amine antiaging agent. By using the four components in combination, the rubbery polymer can be easily crosslinked by simply leaving it for a few days at a relatively low temperature of, for example, about 50°C.

Generally, the above-mentioned rubbery polymers have few crosslinkable double bonds in their molecules, so they cannot be crosslinked unless they are treated at high temperatures for a long time. are not suitable for adhesive purposes of the present invention.

In contrast, the crosslinking agent of the present invention is suitable for adhering vulcanized rubber molded products because it can be crosslinked at low temperatures and in a short time, as described above, and this crosslinking improves the elasticity of this type of molded product. A high cohesive force can be obtained that can sufficiently withstand the repulsive force caused by the action.

Among such crosslinking agents, examples of divalent amphoteric metal oxides include zinc oxide, cadmium oxide, and lead oxide. As the metal chloride, zinc chloride, tin chloride, etc. are preferable. Examples of the organic super-vulcanization accelerator include thiurams (thiuram-based vulcanization accelerators), dithiocarbamates, and xanthates, with dithiocarbamates and xanthates being particularly preferred. Further, as the aromatic secondary amine anti-aging agent, N・N′-diphenyl-p-phenylenediamine, N・N′-di-2-
Preferred are naphnal-p-phenylenediamine, phenyl-1-naphthylamine, and the like.

[0016] In the present invention, it is important to use a combination of the above-mentioned four components: divalent amphoteric metal oxide, metal chloride, organic supervulcanization accelerator, and aromatic secondary amine anti-aging agent. Even if any one of them is missing, the effects of the present invention cannot be obtained. For example, a divalent amphoteric metal oxide acts as a crosslinking agent in the present crosslinking system, and if this is lacking, crosslinking itself will not proceed. This metal oxide also plays the role of capturing hydrogen halide, which is generated from halogenated butyl rubber and causes deterioration. Both metal chlorides and organic supervulcanization accelerators act as active crosslinking accelerators, and if either one is lacking, high temperature and long-term treatment is required for crosslinking. In addition to its role as an anti-aging agent, the aromatic secondary amine anti-aging agent also acts as a cross-linking agent, and without it, cross-linking will be extremely slow, and at relatively low temperatures, sufficient cross-linking will not occur. It doesn't progress.

In the crosslinking agent of the present invention, the amount of the above four components used is 0.2 to 20 parts by weight, preferably 1 to 20 parts by weight of the divalent amphoteric metal oxide per 100 parts by weight of the rubbery polymer. 10 parts by weight, metal chloride 0.1 to 10 parts by weight, preferably 1 to 5 parts by weight, organic supervulcanization accelerator 0.1 to 10 parts by weight, preferably 1 to 5 parts by weight, aromatic The amount of the secondary amine anti-aging agent is 10 parts by weight or less, preferably 0.1 to 3 parts by weight. If it is outside these ranges, the crosslinking reaction will not proceed well or there will be too much crosslinking, making it impossible to obtain good adhesive properties.

In the present invention, a rubber-based pressure-sensitive adhesive composition is prepared by using the above-mentioned rubbery polymer and crosslinking agent as essential components, and adding various optional components as necessary. Optional components include polymers other than the above-mentioned rubbery polymers, tackifying resins, softeners, and the like.

As polymers other than the above-mentioned rubbery polymers, for example, butyl rubber, ethylene-propylene terpolymer, polyisobutylene, polychloroprene, styrene-butadiene copolymer rubber, etc. are preferably used for the purpose of adjusting adhesive properties. , it may be a polymer other than the rubber component. These optional polymers are
Usually 200 parts per 100 parts by weight of the above rubbery polymer
It is preferable that the proportion be less than parts by weight.

[0020] As the tackifier resin, terpene resin,
Tackifier resins that are solid at room temperature, such as terpene-phenol resin, coumaron-indene resin, styrene resin, rosin resin, xylene resin, phenol resin, and petroleum resin, as well as various tackifier resins that are liquid at room temperature. can be used. The amount used is preferably 300 parts by weight or less per 100 parts by weight of the rubbery polymer.

[0021] Examples of the softening agent include process oil, polyester plasticizer, polybutene, and liquid rubber. The amount used is the rubbery polymer 1
The amount is usually 200 parts by weight or less per 00 parts by weight.

In addition to these optional ingredients, various compounding agents used in general pressure-sensitive adhesives, such as antioxidants, ultraviolet absorbers, fillers, pigments, extenders, etc., may be added. The blending amount may be a conventionally known blending amount,
Not specifically specified.

The rubber-based pressure-sensitive adhesive composition prepared in this manner is usually prepared as a solution using an appropriate organic solvent such as toluene, hexane, heptane, etc., and is used as a pressure-sensitive adhesive for vulcanized rubber molded products. It is used as an agent for various purposes.

In this use, the above adhesive solution may be applied directly to an adherend consisting of a vulcanized rubber molded article, but it is usually a pressure-sensitive film layered on a suitable base material. Good to use as an adhesive. In this case, a layer may be formed on only one side of the base material, but for the purpose of adhering the vulcanized rubber molded product to other adherends, a so-called double-sided adhesive sheet, in which a layer is formed on both sides of the base material, is used. It is desirable to do so.

In order to obtain such a double-sided adhesive sheet, for example, the above-mentioned adhesive solution is first coated on a release paper and dried to form a layer, two of these are prepared, and these are pasted on both sides of the base material. Bye. After pasting, for example, about 5
If left at 0° C. for a few days, the crosslinking reaction will naturally proceed due to the action of the four-component crosslinking agent, resulting in an adhesive layer with high cohesive strength.

The base material is usually a porous base material such as nonwoven fabric, woven fabric, or paper, or a plastic film such as polyester film, polyethylene film, polypropylene film, or polyvinyl chloride film, and has a thickness of 5.
A thickness of approximately 200 μm is used. If you use plastic film and leave it for a long time after using the adhesive,
Since it is possible to prevent the adhesion-inhibiting component from transferring from one side of the film to the other side, a decrease in adhesive strength over time is suppressed. Note that if these base materials are subjected to undercoating treatment before providing the adhesive layer, the anchoring power of the adhesive will be improved.

[0027] The adhesive layer provided on this base material, that is, the layer of the rubber-based pressure-sensitive adhesive composition, preferably has a thickness of usually about 10 to 400 μm on one side, but is not limited to this. It can be determined as appropriate depending on the purpose of use.

In addition, when obtaining a double-sided adhesive sheet, a layer of the above-mentioned rubber-based pressure-sensitive adhesive composition is provided only on one side of the base material, and another adhesive composition, especially an acrylic-based pressure-sensitive adhesive composition, is provided on the other side. Modifications may also be made, such as providing a layer of adhesive composition.

According to this embodiment, a layer of a rubber-based pressure-sensitive adhesive composition can be used for adhesion to the vulcanized rubber molded article, and the above-mentioned acrylic-based pressure-sensitive adhesive composition can be used for adhesion to other adherends. The availability of layers such as compositions may provide more desirable adhesive properties depending on the intended use. Note that the layer of the above-mentioned acrylic pressure-sensitive adhesive composition may contain various additives such as coloring pigments as appropriate, as in the case of the layer of the rubber-based pressure-sensitive adhesive composition.

[0030]

As described above, in the present invention, a specific polymer is used as the main component of the adhesive, and a specific crosslinking agent for crosslinking this polymer is blended, thereby making it possible to mold vulcanized rubber. When adhering products, especially when attaching this molded product to an adherend with a curved surface, it is possible to bond products without the need for conventional treatments such as buffing or primer application.
A pressure-sensitive adhesive that exhibits sufficient adhesive strength can be obtained.

[0031]

[Examples] Next, examples of the present invention will be specifically explained in comparison with comparative examples. In addition, hereinafter, parts shall mean parts by weight.

Example 1 Brominated butyl rubber (weight average molecular weight 500,000)
100 parts polyisobutylene (weight average molecular weight 100,000) 8
0 parts Petroleum resin (softening point 100℃)
70 copies
Terpene liquid resin
50 copies
zinc oxide

5 parts zinc chloride

1 part Zinc diethyldithiocarbamate
4 parts N・N'-diphenyl-p-phenylenediamine 2 parts

A solution of a rubber-based pressure-sensitive adhesive composition was prepared by dissolving each of the above components in 630 parts of toluene. This solution was applied onto the release liner using an applicator so that the thickness after drying was 70 μm, and dried at 100° C. for 3 minutes.

Next, two layers of the rubber thread pressure-sensitive adhesive composition formed on the above-mentioned release liner were prepared, and these were laminated on both sides of a nonwoven fabric with a thickness of 50 μm. A film-like pressure-sensitive adhesive was produced by leaving the mixture at 2 days at ℃.

Example 2 Chlorinated butyl rubber (weight average molecular weight 500,000)
100 parts Liquid polyisobutylene (weight average molecular weight 30,000) 60
Part Petroleum resin (softening point 100℃)
100 parts zinc oxide
5
Part tin chloride

Part 2 Tellurium dimethyldithiocarbamate 2
Part N・N'-di-2-naphthyl-p-phenylenediamine 1 part

[0036] Each of the above components was dissolved in 658 parts of toluene to prepare a solution of a rubber-based pressure-sensitive adhesive composition. Using this solution, Example 1 will be described below.
A film-like pressure-sensitive adhesive was prepared in the same manner as above.

Example 3 Brominated butyl rubber (weight average molecular weight 500,000)
100 parts Polyisobutylene (weight average molecular weight 100,000) 100
Part Petroleum resin (softening point 95℃)
90 copies
Petroleum-based liquid resin
40 copies
zinc oxide

5 parts zinc chloride

Part 2 Zinc isopropyl xanthate
2 parts N・N'-diphenyl-p-phenylenediamine 0.5 part

A solution of a rubber-based pressure-sensitive adhesive composition was prepared by dissolving each of the above components in 630 parts of toluene. Using this solution,
Thereafter, a film-like pressure-sensitive adhesive was produced in the same manner as in Example 1.

Example 4 Brominated butyl rubber (weight average molecular weight 500,000)
100 parts polyisobutylene (weight average molecular weight 800,000) 2
0 parts Polyisobutylene (weight average molecular weight 100,000) 70 parts Petroleum resin (softening point 95°C)
80 parts Terpene liquid resin
50 parts lead oxide

Part 5 Tin chloride
Part 2 Zinc Butylxanthate
2nd part
Phenyl-1-naphthylamine
0.2 parts

A solution of a rubber-based pressure-sensitive adhesive composition was prepared by dissolving each of the above components in 613 parts of toluene. Using this solution,
Thereafter, a film-like pressure-sensitive adhesive was produced in the same manner as in Example 1.

Example 5 70 parts of n-butyl acrylate, 27 parts of 2-ethylhexyl acrylate, 3 parts of acrylic acid, and 233 parts of ethyl acetate.
The monomer solution of 1.0 parts was radically polymerized by a conventional method to obtain a polymer solution containing an acrylic polymer having a weight average molecular weight of 550,000 and having a solid content of 30% by weight. To this, rosin-based tackifying resin (
A solution of an acrylic pressure-sensitive adhesive composition was prepared by adding and mixing 30 parts (softening point: 100°C).

Next, a solution of the rubber-based pressure-sensitive adhesive composition of Example 1 was applied to one side of a polyester film having a thickness of 25 μm so that the dry thickness would be 70 μm, and the solution was heated at 100° C. After drying for 3 minutes, it was further left at 50°C for 2 days. Thereafter, a solution of the above-mentioned acrylic pressure-sensitive adhesive composition was applied to the other side of this polyester film so that the dry thickness would be 70 μm, and it was dried at 100°C for 3 minutes to form a film. A pressure-sensitive adhesive was prepared.

Comparative Example 1 Brominated butyl rubber (weight average molecular weight 500,000)
100 parts polyisobutylene (weight average molecular weight 100,000) 8
0 parts Petroleum resin (softening point 100℃)
70 copies
Terpene liquid resin
50 copies
zinc oxide

5 parts zinc chloride

1 part Tetramethylthiuram disulfide
4th part

[0044] Each of the above components was dissolved in 638 parts of toluene to prepare a solution of a rubber-based pressure-sensitive adhesive composition. In the same manner as in Example 1 except that this solution was used,
A film-like pressure-sensitive adhesive was produced.

Comparative Example 2 Butyl rubber (weight average molecular weight 500,000)
100 parts polyisobutylene (weight average molecular weight 400,000)
70 parts petroleum resin (softening point 100℃)
120 copies
Terpene liquid resin
120 copies
zinc oxide

5 parts Tellurium dimethyldithiocarbamate
4th part
N・N'-diphenyl-p-phenylenediamine
2nd part

[0046] Each of the above components was dissolved in 630 parts of toluene to prepare a solution of a rubber-based pressure-sensitive adhesive composition. A film-like pressure-sensitive adhesive was produced in the same manner as in Example 1 except that this solution was used.

Comparative Example 3 A solution of the acrylic pressure-sensitive adhesive composition used in Example 3 was applied onto a release liner using an applicator so that the thickness after drying was 70 μm. , 100
It was dried at ℃ for 3 minutes.

Next, two layers of an acrylic pressure-sensitive adhesive composition formed on the release liner are prepared.
A film-like pressure-sensitive adhesive was produced by laminating these on both sides of a nonwoven fabric with a thickness of 50 μm.

The adhesive strength and curved surface adhesion characteristics of each of the film-like pressure-sensitive adhesives obtained in Examples 1 to 3 and Comparative Examples 1 to 3 were measured, and the results are shown in Table 1 below. It was exactly as expected. Note that the measurement tests for adhesive strength and curved surface adhesion characteristics were conducted in the following manner.

<Adhesive force> Using a vulcanized rubber plate as the adherend, the adhesive force (g/2
0 mm width) was measured.

<Curved surface attachment characteristics> 10mm x 100m
A vulcanized rubber plate with a size of m is wiped dry with a rag, and one side of a film-like pressure-sensitive adhesive is pasted with a 2 kg roll going back and forth once. Next, peel off the release paper and put 5 kg on the other side.
Using a roll, attach it to a stainless steel cylinder with a diameter of 200 mm. After being left at 50° C. for 2 days, the height of the float from the end surface was measured.

In the above two measurement tests, the vulcanized rubber plates were a 3 mm thick chloroprene rubber plate (Neo-180 manufactured by Irumagawa Rubber Co., Ltd.) and a 3 mm thick EPT rubber plate.
A rubber plate (EP-5065 manufactured by Irumagawa Rubber) was used. Further, the film-like pressure-sensitive adhesive of Example 3 was measured with the layer of the rubber-based pressure-sensitive adhesive composition in contact with the vulcanized rubber plate side.

[0053]

[Table 1]

As is clear from the results in Table 1 above, the film-like pressure-sensitive adhesive of the present invention does not require conventional treatments such as buffing and primer coating on a vulcanized rubber plate. It can be seen that very good adhesive properties can be obtained even without this.

Claims (3)

[Claims] Claim 1: The main component is halogenated butyl rubber,
Per 100 parts by weight of this rubbery polymer, 0.2 to 20 parts by weight of a divalent amphoteric metal oxide and 0.1 to 0.1 to 20 parts by weight of a metal chloride.
10 parts by weight of an organic yarn super-vulcanization accelerator, and 10 parts by weight or less of an aromatic secondary amine antioxidant. Pressure adhesive. 2. A film-like pressure-sensitive adhesive comprising a base material and a layer of the rubber-based pressure-sensitive adhesive composition according to claim 1 on both sides of the base material. 3. A layer of the rubber-based pressure-sensitive adhesive composition according to claim (1) is provided on one side of the base material, and a layer of the acrylic-based pressure-sensitive adhesive composition is provided on the other side. A film-like pressure-sensitive adhesive.