JPH0781124B2 - Pressure sensitive adhesive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a pressure-sensitive material used for bonding a vulcanized rubber molded product made of natural rubber, chloropropylene rubber, EPT (ethylene-propylene terpolymer) rubber, or the like. Regarding adhesives.

[Conventional technology]

This type of vulcanized rubber molded product is widely used as various industrial products in addition to automobile parts, home appliances, and OA equipment parts.

However, these rubber molded products contain a large amount of various fillers, vulcanizing agents, adhesion-inhibiting substances such as oil components as a compound,
Moreover, since a mold release agent such as silicone oil is used in order to improve the mold release from the press mold in the step of vulcanizing the rubber molded product, the adhesiveness of the surface of the molded product is poor.

Moreover, since these vulcanized rubber molded products have high elasticity, when they are attached to a curved surface, they are bonded and fixed in a state in which stress is applied by the above elastic action. Due to the poor adhesiveness of the molded product, there is a problem that the molded product is easily peeled off after being bonded and fixed.

For this reason, conventionally, the adhered surface of the vulcanized rubber molded product is first buffed, then solvent-washed and primer-coated, and then a film-shaped pressure-sensitive adhesive is attached onto the adhered surface. When it was adhered and fixed to the adherend, the method was adopted.

[Problems to be Solved by the Invention]

However, the processing such as buffing and primer coating described above may increase the number of steps and may deteriorate the working environment by scattering buffing powder or solvent, and in the buffing step,
There is a problem in that the degree of buffing tends to vary, and the adhesive strength also varies accordingly.

The present invention, in view of the above circumstances, for vulcanized rubber molded articles,
It is an object of the present invention to provide a pressure-sensitive adhesive that can obtain sufficient adhesive strength without the conventional treatment such as buffing and primer coating.

[Means for Solving the Problems]

As a result of intensive studies to achieve the above-mentioned object, the present inventors have used a specific polymer as a main component of an adhesive and, at the same time, added a specific crosslinking agent for crosslinking this polymer to a pressure-sensitive property. It was found that an adhesive can sufficiently bond a vulcanized rubber molded product without performing conventional treatments such as buffing and primer coating, and thus completed the present invention.

That is, the present invention is based on a butyl rubber and / or a halogenated butyl rubber as a main component.
Pressure sensitivity using a rubber-based pressure-sensitive adhesive composition containing 0.5 to 10 parts by weight of a quinonedioxime compound, 0.1 to 5 parts by weight of an organic peroxide, and 0.01 to 5 parts by weight of a redox catalyst per 0 part by weight. It relates to an adhesive.

[Constitution / Operation of Invention]

The rubbery polymer according to the present invention has a high affinity with a vulcanized rubber molded product, and has isobutylene and 1 as a polymer that exhibits selective wettability by eliminating the adhesion-inhibiting substance in the surface layer.
Either or both of butyl rubber, which is a copolymer with 3 wt% isoprene, and halogenated butyl rubber obtained by brominated or chlorinated this rubber are used. The weight average molecular weight of these rubbery polymers is 200,000 to 10
It should be 0,000.

The present invention is characterized by containing such a rubbery polymer as a main component and incorporating a specific cross-linking agent therein, which is desired for a pressure-sensitive adhesive which is insufficient by the above-mentioned polymer alone. A high cohesive force is given,
A strong adhesive strength that can withstand the repulsive force of the vulcanized rubber molded product can be obtained.

The specific cross-linking agent used here is composed of three components of a quinone dioxime compound, an organic peroxide and a redox catalyst, and by using these three components in combination, the rubbery polymer, for example, at about 50 ° C. 2, at relatively low temperatures
Crosslinking is easy by leaving it for 3 days.

In general, the above-mentioned rubbery polymer cannot be crosslinked unless it is treated at high temperature for a long time because the number of crosslinkable double bonds present in the molecule is small. It is not suitable for the purpose of adhesion of the invention.

On the other hand, according to the cross-linking agent of the present invention, as described above, since it can be cross-linked at low temperature in a short time, it is suitable for the purpose of adhering a vulcanized rubber molded article, and this cross-linking is based on the elastic action of this kind of molded article A high cohesive force that can sufficiently withstand the repulsive force is obtained.

Among such cross-linking agents, examples of quinonedioxime compounds include p-benzoquinonedioxime and its derivative p-benzoquinonedioxime dibenzoate. As the organic peroxide, hydroperoxide,
Organic peroxides such as diacyl peroxide, ketone peroxide and dialkyl peroxide are preferred.
The redox-based catalyst, nickel, cobalt, as a reducing agent that generates radicals by the reaction with the peroxide,
Organic or inorganic metal salts such as chromium, manganese and iron are preferred.

In the present invention, the above quinone dioxime compound,
It is important to use the three components of the organic peroxide and the redox catalyst in combination, and the effect of the present invention cannot be obtained even if any one of them is omitted. For example, with only two components of an organic peroxide and a quinonedioxime compound, or with only two components of an organic peroxide and a redox catalyst,
The generation of radicals requires a high temperature for a long time, and the polymer radicals are preferentially decomposed and cleaved by the attack of the polymer by the generated radicals, so that the crosslinking reaction of the target polymer hardly progresses.

On the other hand, according to the above-mentioned three-component system of the present invention, a radical is rapidly generated by the reaction between the organic peroxide and the redox-based catalyst, and then this radical attacks the quinonedioxime-based compound, and in the reaction, It is presumed that a certain nitroso compound further attacks the rubbery polymer, and successfully leads to cross-linking without decomposing or cleaving the polymer.

In the crosslinking agent of the present invention, the amount of the above three components used is 0.5 to 10 parts by weight, preferably 1 to 3 parts by weight of the quinonedioxime compound per 100 parts by weight of the rubbery polymer.
Parts by weight, 0.1 to 5 parts by weight of organic peroxide, preferably 0.2
To 2 parts by weight, 0.01 to 5 parts by weight, preferably 0.1 to 2 parts by weight of the redox catalyst. When the amount is out of these ranges, the above-mentioned crosslinking reaction does not proceed well, or the amount of crosslinking is excessive, so that good adhesive properties cannot be obtained.

In the present invention, the rubber-based pressure-sensitive adhesive composition is prepared by using the rubber polymer and the cross-linking agent as essential components, and mixing various optional components as necessary. The optional components include polymers other than the rubbery polymers described above, tackifying resins, softening agents and the like.

As the polymer other than the rubbery polymer, for example, ethylene-propylene terpolymer, polyisobutylene, chloroprene, styrene-butadiene copolymer rubber and the like are preferably used for the purpose of adjusting the adhesive property, but other polymers other than the rubber component. May be The amount of the polymer as an optional component is usually 200 parts by weight or less per 100 parts by weight of the rubbery polymer.

Examples of the tackifying resin include terpene-based resins, terpene-phenol-based resins, chroman-indene resins, styrene-based resins, rosin-based resins, xylene-based resins, phenol-based resins, petroleum-based resins, and other solid tackifier resins at room temperature. In addition, various tackifying resins that are liquid at room temperature can be used. The amount used is usually 300 parts by weight or less per 100 parts by weight of the rubbery polymer.

Examples of the softening agent include process oil, polyester plasticizer, polybutene, liquid rubber and the like. The amount used is usually 200 parts by weight or less per 100 parts by weight of the rubbery polymer.

In addition to these optional components, various compounding agents used in general pressure-sensitive adhesives, such as antioxidants, ultraviolet absorbers, fillers, pigments and extenders, may be compounded. The blending amount may be a conventionally known blending amount and is not particularly limited.

The rubber-based pressure-sensitive adhesive composition thus adjusted,
Usually, it is a solution using an appropriate organic solvent such as toluene, hexane, heptane, and is used for various purposes as a pressure-sensitive adhesive for vulcanized rubber molded products.

In this use, the above adhesive solution may be directly applied to an adherend composed of a vulcanized rubber molded article, but usually as a film-like pressure-sensitive adhesive layered on an appropriate substrate. Good to use. 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 article to another adherend, a so-called double-sided adhesive sheet is formed on both sides of the base material. Is desirable.

In order to obtain such a double-sided adhesive sheet, for example, the adhesive solution may be once applied and dried on a release paper to form a layer, two of these may be prepared, and these may be attached to both sides of the base material. After bonding, if left at, for example, about 50 ° C. for a few days, the ternary crosslinking agent spontaneously promotes a crosslinking reaction to form an adhesive layer having a large cohesive force.

As the substrate, a non-woven fabric, a woven fabric, a porous substrate such as paper,
A polyester film, a polyethylene film, a polypropylene film, a polyvinyl chloride film, or another plastic film having a thickness of about 5 to 200 μm is usually used. When the plastic film is used, the adhesive component can be prevented from migrating from one surface side of the film to the ground side when the adhesive film is left for a long time after the adhesive is used.

The adhesive layer provided on this substrate, that is, the layer of the rubber-based pressure-sensitive adhesive composition, has a thickness of usually 10 on one side.
The thickness is preferably about 400 μm, but is not limited to this and can be appropriately determined according to the purpose of use.

Further, in the case of obtaining a double-sided adhesive sheet, a layer of the rubber-based pressure-sensitive adhesive composition is provided only on one surface of the substrate, and another adhesive composition, particularly an acrylic pressure-sensitive adhesive composition, is provided on the other surface. The layers of material may be modified in any manner.

According to such an embodiment, adhesion to a vulcanized rubber molded article can utilize a layer of a rubber-based pressure-sensitive adhesive composition, and adhesion to other adherends can be performed using the acrylic-based pressure-sensitive adhesive composition or the like. Depending on the intended use, more desirable adhesive properties may be obtained, since these layers can be used.

〔The invention's effect〕

As described above, in the present invention, using a specific polymer as the main component of the adhesive, and by blending a specific cross-linking agent for cross-linking this polymer, in adhering the vulcanized rubber molded article, In particular, when this molded product is attached to an adherend having a curved surface, it is possible to obtain a pressure-sensitive adhesive exhibiting sufficient adhesive strength without performing conventional treatments such as buffing and primer coating. it can.

〔Example〕

Next, examples of the present invention will be specifically described in comparison with comparative examples. In the following, "parts" means "parts by weight".

Example 1 Butyl rubber (weight average molecular weight 500,000) 100 parts Polyisobutylene (weight average molecular weight 400,000) 70 parts Petroleum resin (softening point 100 ° C.) 120 parts Terpene liquid resin 120 parts p-benzoquinone dioxime 2 parts Cumene hydroper Oxide 0.5 part Cobalt naphthenate solution (cobalt content 6% by weight, naphthenic acid content 43% by weight) 1 part The above components were dissolved in 630 parts of toluene to prepare a rubber-based pressure-sensitive adhesive composition solution. . This solution was applied on a 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-based pressure-sensitive adhesive composition formed on the above-mentioned release liner were prepared, and these layers had a thickness of
After sticking on both sides of a 50 μm non-woven fabric, the film was left at 50 ° C. for 2 days to prepare a film-like pressure-sensitive adhesive.

Example 2 Brominated butyl rubber (weight average molecular weight 500,000) 100 parts Liquid polyisobutylene (weight average molecular weight 30,000) 150 parts Petroleum resin (softening point 100 ° C) 100 parts p-benzoquinone dioxime dibenzoate 2 parts Cumene hydroperoxide 0.5 part Cobalt naphthenate (the same as in Example 1) 2 parts The above components were dissolved in 658 parts of toluene to prepare a solution of a rubber-based pressure-sensitive adhesive composition. Using this solution, a film-like pressure-sensitive adhesive was prepared in the same manner as in Example 1 below.

Example 3 Radical polymerization of a monomer solution of 70 parts of n-butyl acrylate, 27 parts of 2-ethylhexyl acrylate, 3 parts of acrylic acid and 233 parts of ethyl acetate by a conventional method to give an acrylic resin having a weight average molecular weight of 550,000. A polymer solution containing a base polymer and having a solid content of 30% by weight was obtained. Acrylic polymer
Rosin-based tackifying resin (softening point 100 ° C) 30 for 100 parts
The parts were added and mixed to prepare a solution of an acrylic pressure-sensitive adhesive composition.

Next, the solution of the rubber-based pressure-sensitive adhesive composition of Example 1 was applied onto one surface of a polyester film having a thickness of 25 μm so that the thickness after drying was 70 μm, and dried at 100 ° C. for 3 minutes. After that, it was further left to stand at 50 ° C. for 2 days. Then, on the other surface of this polyester film, a solution of the above acrylic pressure-sensitive adhesive composition was dried to a thickness of 70 μm.
m to obtain a film-shaped pressure-sensitive adhesive, which was dried at 100 ° C. for 3 minutes.

Example 4 Brominated butyl rubber (weight average molecular weight 450,000) 100 parts Liquid polyisobutylene (weight average molecular weight 80,000) 80 parts Petroleum resin (softening point 70 ° C.) 120 parts p-benzoquinone dioxime 2 parts p-menthane hydroperoxide 0.5 part Vanadyl octoate 1 part The above components were dissolved in 370 parts of toluene to prepare a solution of a rubber pressure-sensitive adhesive composition. Using this solution, a film-like pressure-sensitive adhesive was prepared in the same manner as in Example 1 below.

Comparative Example 1 Butyl rubber (weight average molecular weight 500,000) 100 parts Polyisobutylene (weight average molecular weight 400,000) 70 parts Petroleum resin (softening point 100 ° C) 120 parts Terpene liquid resin 120 parts p-benzoquinone dioxime 2 parts Pb ₃ O ₄ (Oxidizing agent) 2 parts Each of the above components was dissolved in 638 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 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 ° C) 120 parts Terpene liquid resin 120 parts p-benzoquinone dioxime 2 parts Cumene hydroper Oxide 0.5 part The above components were 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 Butyl rubber (weight average molecular weight 500,000) 100 parts Polyisobutylene (weight average molecular weight 400,000) 70 parts Petroleum resin (softening point 100 ° C) 120 parts Terpene liquid resin 120 parts Cumene hydroperoxide 0.5 part Cobalt naphthenate ( (Same as in Example 1) 2 parts The above components were 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 4 A solution of the acrylic pressure-sensitive adhesive composition used in Example 3 was applied on a release liner using an applicator so that the thickness after drying was 70 μm, and then 100 ° C. And dried for 3 minutes.

Next, prepare two layers of acrylic pressure-sensitive adhesive composition formed on this release liner, and stick these layers on both sides of a non-woven fabric with a thickness of 50 μm to obtain a film-like pressure-sensitive adhesive. An adhesive was prepared.

With respect to the film-shaped pressure-sensitive adhesives obtained in Examples 1 to 4 and Comparative Examples 1 to 4, the results of measuring the adhesive force and the curved surface sticking property are as shown in Table 1 below. It was. In addition, the measurement test of the adhesive force and the curved surface sticking property was performed in the following manner.

<Adhesive Strength> Using a vulcanized rubber plate as an adherend, the adhesive strength (g / 20 mm width) was measured according to JIS Z-1528.

<Curved surface sticking characteristics> A 10 mm x 100 mm vulcanized rubber plate is wiped dry with a waste cloth, and a 2 kg roll 1 on one side of the film-shaped pressure-sensitive adhesive is used.
Stick it back and forth. Next, the release paper is peeled off, and the other side is attached to a stainless steel cylinder having a diameter of 200 mm using a 5 kg roll. After standing at 50 ° C. for 2 days, the height of floating from the end face was measured.

In the above two measurement tests, as the vulcanized rubber plate, a chloroprene plate having a thickness of 3 mm (Neo-18 made by Irumagawa Rubber was used.
0) and an EPT rubber plate with a thickness of 3 mm (EP-506 made by Irumagawa Rubber)
5) and were used. Further, the film-shaped pressure-sensitive adhesive of Example 3 was measured so that the layer of the rubber-based pressure-sensitive adhesive composition was in contact with the vulcanized rubber plate side.

As is clear from the results shown in Table 1 above, the film-shaped pressure-sensitive adhesive of the present invention enables the vulcanized rubber plate to be subjected to no conventional treatment such as buffing or primer coating. It can be seen that very good adhesive properties can be obtained.

Claims (3)

[Claims] 1. A butyl rubber and / or a halogenated butyl rubber as a main component, and 0.5 to 10 parts by weight of a quinonedioxime compound, 0.1 to 5 parts by weight of an organic peroxide, and a redox catalyst per 100 parts by weight of these rubbery polymers. 0.01
A pressure-sensitive adhesive using a rubber-based pressure-sensitive adhesive composition containing 5 to 5 parts by weight. 2. A film-shaped pressure-sensitive adhesive having a layer of the rubber-based pressure-sensitive adhesive composition according to claim 1 on both sides of a substrate. 3. A layer of the rubber-based pressure-sensitive adhesive composition according to claim 1 is provided on one surface of the base material, and an acrylic-based pressure-sensitive adhesive composition layer is provided on the other surface. Film-like pressure sensitive adhesive.