JPH08176314A - Method for bonding cured rubber/cured rubber - Google Patents

Abstract

PURPOSE: To provide a cured rubber/cured rubber bonding method intended to address such problems as inadequate bonding due to residual buff powder after buffing, the troublesomeness of handling such portions to be bonded afterward as a result of leaving the portions uncured, and buffing operation itself, and to ensure effects equivalent to those of buffing to be realized more easily and enable firm bonding to be accomplished. CONSTITUTION: A sheetlike material with unevennesses at least on one side, easy to p,eel off cured rubbers after curing is introduced, in advance, onto the surface of a portion in yet uncured state for the cured rubbers to be mutually bonded at least afterward, and a curing is then carried out. And just before bonding, the sheetlike material is peeled off the surface, thereby providing the surface of the cured rubbers with moderate unevennesses favorable for bonding and also rendering the surface fresh. Furthermore, a bonding rubber higher in sulfur content than both the cured rubbers to be mutually bonded is taken as such a rubber as to be inserted in between the cured rubbers prior to their bonding, thus ensuring higher bonding to be accomplished.

Description

Detailed Description of the Invention

[0001]

[Industrial field of application] A method for bonding vulcanized rubbers such as a conveyor belt and a rubber crawler.

[0002]

2. Description of the Related Art Conventionally, as a method for adhering vulcanized rubbers, in particular, for adhering vulcanized rubbers when joining both end portions to each other for endless use such as a conveyor belt or a rubber crawler, A method in which a surface of a vulcanized rubber is buffed, an adhesive such as rubber cement is applied to the surface, and unvulcanized rubber is superposed on the surface of the vulcanized rubber for vulcanization and adhesion is generally used.

However, when buffing as described above,
It is difficult to completely remove the generated buff powder,
This makes it difficult to obtain perfect adhesion. Alternatively, there is a problem that the working environment is deteriorated because it is necessary to apply an adhesive such as rubber cement. Therefore, there is a method in which the surface to be bonded in advance during vulcanization is left in an unvulcanized state, and finally the unvulcanized rubber portion is bonded and vulcanized and bonded. However, in this case, since the adhesive part is left in an unvulcanized state, it is difficult to remove from the mold, and due to the stickiness of the unvulcanized rubber part,
There is a problem in that, for example, endless work must be performed with sufficient care when handling the unvulcanized part and adhering work.

[0004]

DISCLOSURE OF INVENTION Problems to be Solved by the Invention As a result of eliminating the above-mentioned problems, the present inventors have made earnest studies on an easier and more complete bonding method, and as a result, a method for solving these problems. The inventors have found the present invention and have reached the present invention.

[0005]

First, the first invention is
At least at the same time as cleaning the surfaces of both vulcanized rubber parts to be adhered to each other, for the purpose of making unevenness, have at least one unevenness on the surface of the adhesive part before vulcanization,
Sheets that are easy to peel off from the rubber after vulcanization, for example,
R _max is 1 to 5000 μm, preferably 20 to 200 μm
Vulcanization is carried out after the sheet-shaped materials of m are piled up or sandwiched. After vulcanization, the sheet-shaped material is peeled off from the rubber immediately before adhesion to the vulcanized rubber of the other party. By doing so, the surface of the rubber from which the sheet-like material has been peeled off can easily be obtained as a surface suitable for adhesion having an uneven surface as when just buffing, and the rubber surface is buffed, etc. It has been found that a clean state can be obtained without stains such as buff powder due to the above, so that the above problems can be solved more easily and stronger adhesion can be obtained as compared with the conventional method.

[0006] Further, as a further invention, the present inventors have made a vulcanized rubber / vulcanized rubber that adheres to each other as an adhesive rubber on the surface of each other or on the surface having at least one of the irregularities suitable for adhesion. It has been found that a strong adhesion can be obtained by using an adhesive rubber having a larger amount of sulfur than the vulcanized rubber between the two and sandwiching it between both adhesive surfaces for vulcanization adhesion. In this case, the adhesive rubber of the present invention may be applied to a vulcanized rubber surface which has been buffed as in the prior art or to which an ordinary rubber cement has been further applied, but in this case, It is necessary to sufficiently remove the buff powder as described above.

[0007]

First, a sheet-like member having at least one surface having unevenness on the surface of the unvulcanized rubber to which the vulcanized rubbers are adhered at least afterwards and easily peeled from the rubber after vulcanization is inserted. Vulcanize above. By peeling off the sheet-like material immediately before adhesion, a suitable degree of unevenness convenient for adhesion can be obtained on the surface of the vulcanized rubber, and the surface can be made a fresh surface. In this respect, conventionally, in the case of a normal mold surface, a rubber compound such as oil, wax, and an antioxidant bleeds over time on the surface of the vulcanized rubber, which becomes a factor that inhibits adhesion. The above problem can be avoided by peeling off the sheet-like material immediately before adhesion.

That is, the first point of the present invention is that, instead of the conventional buffing, it is simpler to use (1) moderate unevenness (anchor effect) on at least the surfaces of the vulcanized rubbers to which the vulcanized rubbers will be bonded later. ) Is easily obtained, and further, (2) the surface to be bonded is easily obtained as a clean surface (bleedless) state.

A second point of the present invention is to use an adhesive rubber, which has a larger amount of sulfur than the vulcanized rubber of the main body, and particularly the difference in the amount of sulfur. That is, by using a rubber of 1 to 10 PHR, it is possible to obtain a rubber having a stronger adhesive force. If the amount of sulfur is equal to or less than that, the migration of sulfur from the adhesive rubber to the vulcanized rubber causes a decrease in elastic modulus, resulting in a decrease in adhesive strength. Further, when the difference in sulfur amount exceeds 10 PHR, the physical properties of the adhesive rubber are deteriorated, and as a result, the adhesive strength is decreased.

[0010]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples. [Example 1] When vulcanizing unvulcanized rubber, at least a portion to be bonded later, that is, a portion to be bonded is made of PET canvas [Ox canvas] (250D / 1 (203/5 cm) x 2)
50D / 2 (122/5 cm) is attached and then vulcanized. After vulcanization, peel off the canvas just before bonding,
Further, as the adhesive rubber, a mixture containing 6 PHR of sulfur was inserted between the vulcanized rubber / vulcanized rubber and vulcanized and adhered. Example 2 An adhesive sample was obtained in the same manner as in Example 1 except that the adhesive surface was buffed and rubber cement was applied without using a canvas. [Comparative Example 1] In the above-mentioned Example 1, without applying canvas,
An adhesive sample was obtained in the same manner as in Example 1 except that the adhesive surface was the mold surface. [Comparative Example 2] An adhesive sample was obtained in the same manner as in Example 1 except that an adhesive rubber having a sulfur content of 2 PHR was used. [Comparative Example 3] An adhesive sample was obtained in the same manner as in Example 1 except that an adhesive rubber having a sulfur content of 13 PHR was used.

Adhesive strength and fatigue strength tests were conducted on the adhesive samples obtained in the above Examples and Comparative Examples. Table 1 shows the results.

[0012]

[Table 1]

The adhesion test method is as follows: 0.5 between vulcanized rubbers
An adhesive rubber having a thickness of mmt is sandwiched and vulcanized. Further, the sample was sliced to have a thickness of 2 mmt. From this sample, punch out a test piece as shown in Figure 1,
Tensile strength (adhesive strength) according to JIS-K6301 standard,
And the fatigue strength (the number of times the elongation was repeated 0 to 100%) were measured. Table 2 shows the formulations of the vulcanized rubber and the adhesive rubber used in the examples and comparative examples.

[Table 2]

[0014]

Industrial Applicability First, at least a portion of the unvulcanized rubber to which the vulcanized rubbers are adhered to each other in advance has unevenness on at least one surface such as canvas, and after vulcanization, the vulcanized rubber Vulcanize after inserting a sheet that is easy to peel off.
Then, just before adhering the two vulcanized rubbers, by peeling off the sheet-like material such as the canvas which is easily peeled off, an appropriate degree of unevenness convenient for adhesion is obtained on the surface of the vulcanized rubber, and the surface is a fresh surface. Therefore, it is possible to obtain the same level of buffing and rubber cement methods as in the prior art, and to obtain a simpler and stronger adhesive force as compared with the methods of buffing and rubber cement. Further, when adhering the vulcanized rubbers whose adhesive portions have been treated so that they can be easily adhered as described above, an adhesive rubber containing a larger amount of sulfur than the amount of sulfur of the vulcanized rubber is adopted. By sandwiching the two vulcanized rubbers between the vulcanized rubbers and vulcanizing them integrally, a stronger adhesive force could be obtained.

[Brief description of drawings]

FIG. 1 JIS-K6301, No. 3 type dumbbell for tensile test

[Explanation of symbols]

 1 Adhesive rubber 2 Vulcanized rubber

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location B29K 105: 24

Claims (4)

[Claims] 1. When bonding vulcanized rubbers together,
Before vulcanizing at least the part to be later bonded to each other, on the surface of the bonded part, a sheet-like material having unevenness on at least one surface and easy to peel off from the vulcanized rubber is laminated. A method for adhering vulcanized rubber / vulcanized rubber, characterized in that vulcanization is performed, and then, immediately before adhering both of the parts, the sheet-like material is peeled off and the parts are adhered to each other. 2. When bonding vulcanized rubbers together,
Before vulcanizing at least the part to be later bonded to each other, on the surface of the bonded part, a sheet-like material having unevenness on at least one surface and easy to peel off from the vulcanized rubber is laminated. 2. The vulcanization according to claim 1, wherein vulcanization is performed, and immediately thereafter, the sheet-like material is peeled off and the corresponding portions are vulcanized and adhered to each other using an adhesive rubber or the like immediately before adhering both the parts. How to bond rubber / vulcanized rubber. 3. When bonding vulcanized rubbers together,
As an adhesive rubber, a vulcanized rubber to be adhered to each other / a vulcanized rubber having an amount of sulfur larger than that of the vulcanized rubber is sandwiched, and the adhesive portion is vulcanized and adhered to each other. Adhesion method of vulcanized rubber / vulcanized rubber. 4. The adhesive rubber having a larger amount is used when the difference between the sulfur amount of the adhesive rubber and the sulfur amount of the vulcanized rubber is in the range of 1 to 10 PHR. Vulcanized rubber / vulcanized rubber bonding method.