JPH0957871A - Manufacture of precured tread for retreated tire and manufacture of retreated tire using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the surfaces adapted to be instantaneously stuck and to improve the sticking strength by vulcanizing to stick both the surfaces to be vulcanized to be stuck of precured tread rubber for a retreated tire and a base tire sticking part rubber via unvulcanized sticking cushion rubber sheet mixed with a specific more sulfur amount than those of the both. SOLUTION: An ox canvas 2 easy to be released later from a vulcanized rubber is embedded in the part of a tread rubber 1 to be stuck with at least a base tire, molded, and then vulcanized. Then, the canvas embedded in the stuck surface is pulled and released. Since the rubber surface 2a thus released becomes uneven convenient for sticking, buffing is not particularly necessary. On the other hand, a sticking cushion rubber 4 containing a more sulfur amount by 1 to 5PHR than those of the tread rubber 1 and the base tire sticking part rubber is sandwiched between the base tire 5 molded in a predetermined shape by buffing and the tread 3, and both are vulcanized and stuck. As a result, the buffing can be omitted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a retreaded tire.

[0002]

2. Description of the Related Art Conventionally, a retreaded tire and a method of manufacturing the same include a so-called base tire in which a pattern portion (tread portion) of the tire groove is worn due to long-term running and use. The newly prepared precure tread is integrally bonded and vulcanized with both of them, that is, the base tire and the new precure tread rubber, through an adhesive rubber, and is reused as a tire again. At this time, in order to strongly bond the adhesive surfaces of the new pre-cure tread rubber and the base tire to each other, the adhesive surfaces of both should be buffed in advance, and the unvulcanized adhesive for adhesion between them should be set as described above. Recycled tires are manufactured by arranging rubber and performing vulcanization adhesion.

[0003]

However, the above method has the following problems. (1) It takes a lot of man-hours to pre-buff the surfaces to be adhered to both the pre-cure tread and the base tire, and in some cases, dedicated equipment is required. (2) Further, the work environment is deteriorated due to dust generation due to the buffing. (3) As the material of the precure tread, it is necessary to take into consideration that it is a material that is easily buffed, so that it tends to be difficult to use wear-resistant rubber or the like. (4) Further, as an unvulcanized adhesive cushion rubber for firmly adhering and vulcanizing the both, a rubber compound similar to that of the base tire adhering portion is usually used, and therefore an adhesive cushion during vulcanizing adhering. The cross-linking agent migrates from the rubber to the base tire, or from the adhesive cushion rubber to the precure tread, and a weak portion is generated at the adhesive interface, and the adhesive portion has a partial or entire durability. May be inferior.

[0005]

According to the present invention, as means for solving the above-mentioned problems, (1) As described in (1), first, the rehabilitation precure tread is vulcanized in a mold. At this time, at least on the surface to be vulcanized and bonded to the base tire later, vulcanized and molded precure tread is previously embedded by embedding a canvas or the like that can be easily peeled off from the rubber after vulcanization in advance, and using this, the base is used. A method for producing a retreaded tire characterized by vulcanizing and adhering to a tire, wherein the precure tread is peeled off from the canvas immediately before the adhering, and thus enormous man-hours are conventionally applied.
Alternatively, the purpose is to obtain a surface similar to that obtained by buffing the rubber surface from which the canvas has been peeled off, which is suitable for adhesion, without deteriorating the working environment.

(2) When the pre-cured tread previously vulcanized and the base tire are integrally adhered and vulcanized as described in claim 2, the vulcanized pre-cure rubber and the base tire adhesive portion rubber compound are blended. Sulfur amount (vulcanizing agent) is 1 than
It is a method for manufacturing a regenerating tire characterized by vulcanizing and adhering through an unvulcanized adhesive cushion rubber that is mixed in an amount of about 5 PHR. As a result, it becomes possible to prevent the strength of the adhesive interface from being lowered due to the migration of the crosslinking agent (sulfur) to the base tire or the pre-cure tread at the adhesive interface between the two and to improve the durability.

(3) In claim 3, the above claims 1 and 2 are used in combination, that is, before vulcanizing the precured tread for retreaded tire in the mold as described in claim 1, After vulcanization, at least after manufacturing a precure tread for retreaded tires by embedding and vulcanizing and molding a canvas or the like that is easy to peel off from the vulcanized rubber in advance where it hits the surface to be vulcanized and bonded to the mating base tire , By peeling off the canvas just before bonding, the surface suitable for bonding (buffed surface) can be obtained instantly. Further, as described in claim 2, when the pre-cure tread and the base tire are integrally vulcanized and bonded, an unvulcanized composition in which the amount of sulfur (crosslinking agent) is larger by 1 to 5 PHR than in the combination of both materials. The method for producing a rehabilitation tire is characterized in that a durable rehabilitation tire is obtained by sandwiching the adhesive cushion rubber of (1) between the two and integrally vulcanizing it.

Further details of the present invention will be described including examples.

As the canvas which can be easily peeled off from the vulcanized rubber in the above-mentioned claim 1, when the material such as the canvas embedded in the unvulcanized rubber is integrally vulcanized and then the vulcanized rubber is used. There is no particular limitation as long as the material can be easily separated from the vulcanized rubber, but the material embedded in the rubber is a material that can sufficiently withstand the vulcanization temperature or time of the rubber. It is necessary, and more preferably, a material that, when peeled off from the material, causes the rubber surface to exhibit the same unevenness as in the conventional buffed state, and from this point, ox canvas (made of PET) Etc. are preferably used. Further, as compared with the conventional case, it is only necessary to peel it off immediately before adhesion, so that it is also preferable that the surface thereof is fresh and a clean surface (breedless) is obtained.

When the pre-cured tread previously vulcanized and the base tire are vulcanized and bonded together, the amount of sulfur is larger than the compounding amount of the pre-cure tread rubber and the base tire adhesive portion rubber. By vulcanizing and bonding through an unvulcanized adhesive cushion rubber having a large amount of 1 to 5 PHR, it is possible to suppress a decrease in adhesive strength at the adhesive interface due to migration of the adhesive crosslinking agent, and to improve adhesive strength. This amount of sulfur needs to be adjusted depending on the thickness of the adhesive cushion rubber sandwiched between the two and the vulcanization conditions.

[0011]

The present invention will be described in more detail with reference to the drawings, but the present invention is not limited to this embodiment. (1) First, as shown in FIG. 1, for example, an ox canvas (made of PET) which is easy to be peeled off from the vulcanized rubber later on at least a portion of the tread rubber 1 prepared by an extruder or the like, which is bonded to the base tire. 2 is buried and molded and then vulcanized. After vulcanization,
Peel off the ox canvas embedded in the adhesive surface. At this time, since the ox canvas and the vulcanized rubber can be easily peeled off, they can be easily peeled off. The rubber surface 2a after this stripping
Since it has an uneven surface that is convenient for adhesion, buffing is not necessary.

(2) On the other hand, between the base tire 5 molded into a predetermined shape by buffing or the like and the above-mentioned pre-cure tread 3, the sulfur content is higher than that of the pre-cure tread rubber and the base tire adhesive portion rubber, for example. Both of them are vulcanized and bonded by sandwiching the cushion rubber 4 having a large amount of 3 PHR.

Table 1 shows the compounding of the rubber used as the retreaded tire of the present invention.

[Table 1]

[0014]

As described above, according to the present invention, (1) the buffing work, which takes a lot of man-hours and has a problem in the working environment, is omitted, and the ox is added to the pre-cure tread rubber in the portion to be pre-bonded. By embedding the canvas, molding and vulcanizing it together, and peeling off the canvas at the time of bonding, a surface suitable for bonding can be obtained instantly. (2) Further, as a second effect of the present invention, vulcanization adhesion is performed by sandwiching an unvulcanized adhesive cushion rubber having a sulfur content of 1 to 5 PHR higher than that of the pre-cure tread and the base tire adhesive portion rubber therebetween. By doing so, the adhesive strength can be further improved.
This has made it possible to manufacture a retreaded tire simply and reasonably.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a tread molded product.

FIG. 2 is a schematic sectional view of a precure tread.

FIG. 3 is a schematic cross-sectional view when molding a retreaded tire.

FIG. 4 is a schematic cross-sectional view when a retreaded tire is completed.

[Explanation of symbols]

 1 Tread extruded product 2 Ox canvas 2a Ox peeling surface 3 Precure tread 4 Adhesive cushion rubber 5 Tires 6 Rehabilitated tires

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location B29K 105: 24 B29L 30:00

Claims (3)

[Claims] 1. When vulcanizing and molding a pre-cure tread for a retreaded tire in a mold, a vulcanization is performed by previously embedding a canvas which is easily peeled from a vulcanized rubber on a surface to be vulcanized and bonded to a base tire. A method for producing a precure tread for a retreaded tire, which comprises molding. 2. In the bonding process between a pre-cure tread for a retreaded tire and a base tire, the surface to be vulcanized has a sulfur content of about 1 to 5 PHR more than that of the pre-cure tread rubber for a retreaded tire and the base tire adhesive part rubber. A method for manufacturing a retreaded tire, characterized in that both are vulcanized and bonded via the unvulcanized cushion rubber sheet for adhesion. 3. (1) When vulcanizing and molding a precured tread for a retreaded tire in a mold, a canvas which is easily peeled off from the vulcanized rubber is embedded in advance on the surface to be vulcanized and bonded to the base tire. A vulcanization-molded precured tread manufacturing method for retreaded tires, and (2) retreaded precured tread for retreaded tires and base tire Sulfur content is 1 to 5 PH higher than that of precure tread rubber and base tire adhesion rubber
A method for producing a retreaded tire, characterized in that both are vulcanized and bonded through an unvulcanized cushion rubber sheet for adhesion, which is mixed in a large amount of R.