JPH05295331A - Double-coated pressure-sensitive adhesive tape for bonding vulcanized rubber - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a double-sided adhesive tape for adhesion of vulcanized rubber, which is unlikely to cause an increase in release force of the release paper after adhering to vulcanized rubber and which can improve workability of removing the release paper during use To do. [Structure] A pressure-sensitive adhesive is provided on both sides of a support (eg, paper, non-woven fabric, etc.) containing 3 × 10 ⁻³ equivalents or more of acidic groups (eg, carboxyl group, phosphoric acid group, etc.) per 1 m ^2. Further, release paper is provided on at least one of them.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is
The present invention relates to a double-sided pressure-sensitive adhesive tape which is less likely to cause an increase in the release force of the release paper and can improve the workability of removing the release paper during use.

[0002]

2. Description of the Related Art Generally, a double-sided adhesive tape for adhering vulcanized rubber (hereinafter abbreviated as double-sided tape) has a release paper on the other surface when one adhesive surface is adhered to the vulcanized rubber. Therefore, when it is desired to bond the vulcanized rubber to another adherend, the release paper is removed and the adhesive surface that appears at that time is used.

[0003]

In this case, after the double-sided tape and the vulcanized rubber are adhered, the peeling force of the release paper from the double-sided tape often increases with the passage of time, and therefore the release paper is removed. There is a problem that workability is reduced.

As a result of investigating the cause of this problem, the inventors of the present invention have found that the main cause of the increase in peeling force is that a basic component (for example, a foaming agent or a stabilizer) usually contained in a vulcanized rubber is added. It was discovered that the nitrogen-containing compound, which is a nitrogen-containing compound, migrates to the double-sided tape side, passes through the support, and finally reaches the release paper.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the problems of the prior art. The double-sided tape support contains a specific amount or more of an acidic group to form a base. It has succeeded in preventing the sexual component from reaching the surface of the release paper, and as a result, preventing an increase in the peeling force.

That is, the present invention is 3 × 10 ^-3 per 1 m ^2.
Provided is a double-sided pressure-sensitive adhesive tape for adhering a vulcanized rubber, wherein a pressure-sensitive adhesive is provided on both sides of a support containing an equivalent amount or more of acidic groups, and release paper is provided on at least one of them.

The vulcanized rubber to which the double-sided tape of the present invention is adhered is not particularly limited. For example, the main raw material is natural rubber, ethylene-propylene copolymer rubber (EPT rubber, EPDM rubber), neoprene rubber, nitrile rubber, Synthetic natural rubber,
It is obtained by vulcanizing or crosslinking natural rubber or synthetic rubber such as butyl rubber, styrene-butadiene rubber, acrylonitrile-butadiene rubber, or the like and molding.

The double-sided tape of the present invention is 3 per 1 m ² .
× 10 ^-3 equivalents or more, preferably characterized by using a support containing 5 × 10 ^-3 or more equivalents of acidic groups. The acidic group is not particularly limited,
Strongly acidic ones may accelerate the deterioration of the support itself over time, so for example, a carboxyl group (-COOH),
Alternatively, a weak acidic group such as a phosphoric acid group (> P = 0 (OH)) is desirable.

Here, 3 × 10 ⁻³ equivalent or more per 1 m ² means that in the case of a monovalent acidic group (for example, a carboxyl group), the free acidic group (neutralization) contained per 1 m ^{2 of} the support is neutralized. Or non-esterified acidic group) is 3 × 10
^-3 mol or more is present, and in the case of a polyvalent acidic group (for example, a phosphoric acid group), the equivalent mol is calculated by multiplying the existing mol number of the acidic group by the valence number. The equivalent weight can be calculated from the amount of the acidic substance attached to the support. If the amount of acidic groups is less than the specific value of the present invention, the effect of suppressing an increase in peeling force cannot be obtained, which is not preferable.

The support used for the double-sided tape of the present invention is
Normal paper, non-woven fabric, film, etc. are not particularly limited,
Paper or non-woven fabric is preferable from the viewpoint of easily containing an acidic group in the support. The material is not particularly limited, and commonly known materials such as cellulose, rayon, polyester and polyamide can be used.

The method for incorporating an acidic group into the above-mentioned support is as follows:
There is no particular limitation as long as the support can contain 3 × 10 ⁻³ equivalents or more of acidic groups. For example, in the case of a non-woven fabric, a substance containing a large amount of acidic groups is used as a binder during production. Alternatively, a method of imparting it during the manufacturing process, such as mixing fibers made of a substance containing a large amount of acidic groups, or a method of providing a solution of a substance containing a large amount of acidic groups after manufacturing the support, The method of giving in a process etc. is mentioned. When paper is used as the support, a substance containing a large amount of acidic groups is usually water-soluble and cannot be applied at the stage of paper making. Therefore, it is desirable to apply it in a separate step such as impregnation.

As the substance containing a large amount of such acidic groups,
A composition containing a large amount of a carboxyl group or a phosphoric acid group, such as a polymer of an inorganic acid such as orthophosphoric acid or polyphosphoric acid, a polymer of an organic acid such as polyacrylic acid or polymethacrylic acid, or a copolymer thereof is used. ..

In the case of impregnating with the acidic substance solution, it may be usually immersed in an aqueous solution of 1 to 10% by weight of the acidic substance and then dried at 80 to 140 ° C. for 1 to 5 minutes.

The pressure-sensitive adhesive used in the present invention is
It is not particularly limited, and can be appropriately selected in consideration of the adhesiveness to vulcanized rubber and the adhesiveness to other adherends. Also,
The release paper is not limited at all, and silicone-treated paper or film-based paper, which is used for general double-sided adhesive tape, is used.

[0015]

INDUSTRIAL APPLICABILITY In the present invention, in the support of double-sided tape,
By containing a specific amount or more of acidic groups, it is estimated that the basic component is trapped by the neutralization reaction in the middle after adhesion to the vulcanized rubber, and therefore the basic component does not reach the surface of the release paper. The release force of the release paper is unlikely to increase, and the workability of removing the release paper during use can be improved.

[0016]

EXAMPLES The present invention will now be described based on examples. Example 1 A thin paper made of rayon having a basis weight of 14 g / m ² was impregnated with a 5% by weight aqueous solution of polyacrylic acid and dried at 130 ° C. for 3 minutes to obtain a double-sided tape support of the present invention. The amount of polyacrylic acid attached to this support was 0.5 g per 1 m ^{2 based on} the weight before and after impregnation (dry), and the amount of attached acidic groups was 6.9 × 10 ⁻³ equivalent per 1 m ^2. Met. An acrylic pressure-sensitive adhesive layer containing polybutyl acrylate as a main component was provided on both surfaces of this support, and a silicone-treated release paper containing polydimethylsiloxane as a main component was provided on one surface of the support of the present invention. A double-sided adhesive tape for bonding vulcanized rubber was obtained.

Example 2 A double-sided pressure-sensitive adhesive tape was obtained in the same manner as in Example 1 except that the concentration of the polyacrylic acid aqueous solution in Example 1 was 2.5% by weight. The amount of polyacrylic acid attached to the support was 0.3 g per 1 m ² , and the amount of attached acidic groups was 4.2 × 10 ⁻³ equivalent per 1 m ² .

Example 3 Rayon thin paper having a basis weight of 14 g / m ² was impregnated with a 3 wt% orthophosphoric acid aqueous solution and dried at 130 ° C. for 3 minutes to obtain a double-sided tape support of the present invention. The amount of orthophosphoric acid attached to this support was 0.4 g per 1 m ² , and the amount of attached acidic groups was 12.2 × 10 ⁻³ equivalent per 1 m ² . An acrylic pressure-sensitive adhesive layer containing polybutyl acrylate as a main component was provided on both sides of this support,
A release paper which was treated with silicone containing polydimethylsiloxane as a main component was provided on one surface to obtain a double-sided adhesive tape for adhering vulcanized rubber of the present invention.

Comparative Example 1 5 wt% was used instead of the polyacrylic acid aqueous solution of Example 1.
Example 1 except that a polyvinyl alcohol aqueous solution was used.
A double-sided tape was obtained in the same manner as. The amount of polyvinyl alcohol attached to the support was 0.6 g per 1 m ² .

Comparative Example 2 A double-sided tape was obtained in the same manner as in Example 1 except that a 10 wt% polyvinyl alcohol aqueous solution was used instead of the polyacrylic acid aqueous solution of Example 1. The amount of polyvinyl alcohol attached to the support was 1.2 g per 1 m ² .

Comparative Example 3 A double-sided tape was obtained in the same manner as in Example 1 except that the rayon thin paper of Example 1 was used as it was without treatment as a support.

The double-sided tapes obtained in Examples and Comparative Examples were
Attached to PDM vulcanized rubber sheet, 23 ℃ × 65%
After being left in an RH atmosphere for 24 hours, the peeling force was measured. In addition, in order to investigate the increase in the peeling force after the passage of time, apart from the above peeling force measurement, after the bonding, the laminate was left in an atmosphere of 23 ° C. × 65% RH for 24 hours, and then further heated at 65 ° C. × 95% R
Leave in H atmosphere for 48 hours, and then 23 ° C × 6 again
The peeling force was measured after standing in a 5% RH atmosphere for 24 hours. The results are shown in Table 1.

Here, the peeling force means the resistance value when a double-sided tape having a width of 50 mm is attached to a vulcanized rubber and the release paper is peeled off in a 180 ° direction at a pulling speed of 300 mm / min. ..

[0024]

[Table 1]

As is clear from the above results, the double-sided pressure-sensitive adhesive tape of the present invention is unlikely to increase the peeling force with time even when adhered to vulcanized rubber.

 ─────────────────────────────────────────────────── --- Continuation of the front page (72) Inventor Yoshihiro Nobukawa 1-2-1, Shimohozumi, Ibaraki City, Osaka Prefecture Nitto Denko Corporation

Claims (3)

[Claims] 1. A vulcanized rubber in which a pressure-sensitive adhesive is provided on both surfaces of a support containing 3 × 10 ⁻³ equivalents or more of acid groups per m ² and release paper is provided on at least one of the supports. Double-sided adhesive tape for adhesion. 2. The acidic group is a carboxyl group (—COO).
H) or a phosphoric acid group (> P = 0 (OH)).
Double-sided adhesive tape for adhesion of vulcanized rubber as described. 3. The double-sided pressure-sensitive adhesive tape for adhering vulcanized rubber according to claim 1, wherein the support is paper or non-woven fabric.