JPH07266500A - Vulcanized rubber and unvulcanized rubber connection structure - Google Patents

Abstract

PURPOSE:To provide a vulcanized rubber and unvulcanized rubber connection structure having a breaking load of above a specified value and excellent durability. CONSTITUTION:In a vulcanized rubber and unvulcanized rubber connecting structure, vulcanized rubber parts are connected through unvulcanized rubber parts, a required breaking load is 150ton/m or more, and a relationship between a sulfur content x (wt.%) of the vulcanized rubber and a sulfur content y (wt.%) of the unvulcanized rubber is shown by expressions 1' and 2' i.e., y<=-1.7x+2.8 and 0.2<=y<=1.65.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vulcanized rubber-unvulcanized rubber joint structure having improved durability.

[0002]

2. Description of the Related Art Conventionally, a large rubber product such as a large rubber gasket is constructed by joining a vulcanized rubber component and a vulcanized rubber component via an unvulcanized rubber component. Then, in such a vulcanized rubber-unvulcanized rubber joint structure, sulfur, which is a vulcanizing agent contained in the unvulcanized rubber part, migrates to the vulcanized rubber part and physical properties of the unvulcanized rubber part are transferred. In order to reduce the amount of sulfur, sulfur is usually blended more in unvulcanized rubber parts than in vulcanized rubber parts.

However, in such a vulcanized rubber-unvulcanized rubber joint structure, a required breaking load is 150 t.
In the case of a large size of on / m or more, sulfur contained in the unvulcanized rubber parts accumulates in the vulcanized rubber part near the boundary between the vulcanized rubber part and the unvulcanized rubber part However, there is a problem in that the durability (load resistance) is impaired because the physical properties of are significantly deteriorated.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a vulcanized rubber-unvulcanized rubber joint structure having a required breaking load of 150 ton / m or more and excellent durability.

[0005]

The vulcanized rubber-unvulcanized rubber joint structure of the present invention is formed by joining vulcanized rubber parts through unvulcanized rubber parts, and has a required breaking load of 150 ton / Sulfur content x (wt%) of the vulcanized rubber part that is m or more
And the sulfur content y (% by weight) of the unvulcanized rubber part have the following relationship.

Y ≦ −1.7x + 2.8 ····· 0.2 ≦ y ≦ 1.65 ················· According to the present invention, as described above, the vulcanized rubber component and the unvulcanized rubber Since the relationship between the sulfur content and the parts is determined, the durability can be improved. Hereinafter, the configuration of the present invention will be described in detail.

(1) Relationship between the required breaking load in the vulcanized rubber-unvulcanized rubber joint structure and the breaking energy near the boundary between the vulcanized rubber part and the unvulcanized rubber part (hereinafter referred to as the sulfur accumulation part breaking energy) (For large rubber products with a required breaking load of 150 ton / m or more): The required breaking load (ton / m) and the sulfur accumulation part breaking energy (kgf / cm ² ) usually have the relationship shown in FIG. It can be seen that the breaking energy (integrated value of tensile strength and elongation) of the sulfur accumulation part needs to be 100 kgf / cm ² or more in order to maintain durability at a required breaking load of 150 ton / m or more. Therefore, also in the present invention, the breaking energy of the sulfur accumulation portion is set to 100 kgf / cm ² or more.

(2) Destruction energy of sulfur accumulation part 100 kgf /
In order to develop cm ² or more, the total amount of sulfur in the sulfur accumulation part must be 2.10% by weight or less: Fig. 2 is a diagram showing the relationship between the amount of sulfur before the sulfur accumulation part and the breaking energy. Destruction energy of sulfur accumulation part in the item (1)
It can be seen that the total amount of sulfur that expresses 100 kgf / cm ² or more is 2.10% by weight or less.

(3) In order to keep the total amount of sulfur in the sulfur accumulation part to 2.10% by weight or less, the amount of sulfur blended in the vulcanized rubber part is
1.65% by weight or less: This relationship is shown in FIG. This FIG. 3 shows the main rubber of H _S 40 in Table 1 below (rubber in which the amount of compounded sulfur was appropriately changed in the masterbatch) was 148 ° C. × 30
The vulcanized sheet was vulcanized with appropriate vulcanization, and the total sulfur content was measured by a sulfur analyzer and the relation between the blended sulfur content was plotted.
It can be seen that the amount of sulfur to be blended must be 1.65% by weight or less to achieve the following.

(4) Relationship between variation of sulfur content in vulcanized rubber part (hereinafter referred to as main rubber) and sulfur content in unvulcanized rubber part (hereinafter referred to as joint rubber) and breaking energy of sulfur accumulation part: From FIG. 4, it is understood that the amount of sulfur compounded in the bonding rubber changes depending on the amount of sulfur compounded in the main rubber in order to develop a breaking energy of 100 kgf / cm ² or more in the sulfur accumulation part. That is, there is the following relationship.

Main body rubber Bonding rubber 0.8 wt% Sulfur blending 1.46 wt% or less 1.0 wt% Sulfur blending 1.11 wt% or less 1.2 wt% Sulfur blending 0.73 wt% or less This FIG. Was press-vulcanized by a conventional method, and the unvulcanized joint rubber shown in Table 2 was attached thereto, and thereafter, the sulfur accumulation part breaking energy and the amount of the joint rubber sulfur of each combination of the press-vulcanized samples of the conventional method were again measured. It is a plot of the relationship.

(5) Relationship between the amount of sulfur compounded in the main rubber and the amount of sulfur compounded in the bonding rubber that exerts a breaking energy of the sulfur accumulation portion of 100 kgf / cm ² or more: The amount of sulfur compounded in the main rubber (sulfur content) is x (% by weight) , If the amount of sulfur compounded with the bonding rubber (sulfur content) is y (% by weight), the region shown in FIG.
That is, it is a region that satisfies the relationship of the following equation.

Y ≦ −1.7x + 2.8 ... 0.2 ≦ y ≦ 1.65 ・ ・ ・ where 0.2 ≦ y is 0.2 If it is less than the above range, the amount of sulfur is too small and the physical properties (particularly the peeling force) is deteriorated in the sulfur accumulation portion. This Fig. 5 shows the breakdown energy of sulfur accumulation part 100kgf obtained from the result of the item (4).
It is created by plotting the relationship between the amount of sulfur compounded with the main rubber and the amount of sulfur compounded with the bonding rubber for expressing at least 1 / cm ² .

Specifically, x is x = 0.7 to 1.5% by weight.
Is preferred. (6) Effect of the bonded rubber on the main rubber: Vulcanized sample of the main rubber with the compounding contents (parts by weight) in Table 1 below 100 mm x 150 m
An unvulcanized sample 100 mm x 150 mm x 6 mm of a joint rubber composed of the compound (parts by weight) shown in Table 2 below was bonded to m x 5 mm to prepare joint structures a to f, and the joint structures a to f were prepared by a conventional method. After vulcanization, the breaking energy of the sulfur accumulated portion, the total amount of sulfur in the sulfur accumulated portion, and the peeling force between the main rubber and the bonded rubber were evaluated. The results are shown in Table 3. here,
Hs represents JIS Hs hardness. Further, “original” in Table 3 means the physical properties of the rubber body itself.

[0015] Note) * 1 Body rubber masterbatch Natural rubber 100 parts by weight SRF carbon black 10 parts by weight ZnO 5 parts by weight Aroma oil 5 parts by weight Total 120 parts by weight

[0016] Note) * 2 Bonded rubber master batch Natural rubber 100 parts by weight SRF carbon black 10 parts by weight ZnO 5 parts by weight Aroma oil 5 parts by weight Total 120 parts by weight

Evaluation method for breaking energy of sulfur accumulated portion : The sulfur accumulated portion was cut out at 0.5 tmm from the sample vulcanized by the above method, the No. 3 dumbbell was punched out, and the breaking energy was measured according to JIS K 6251. Evaluation method of total amount of sulfur in sulfur accumulation part : A sample obtained by cutting out the sulfur accumulation part of the laminated structure manufactured in the above (6) at 0.5 tmm is used to measure the total amount of sulfur by EMIA-510 manufactured by Hakuba Seisakusho. Sulfur accumulation part peeling force evaluation method : The laminated structure produced in (6) above was cut into 25mm width pieces in a zigzag shape, and with a Shimadzu autograph, the tensile peeling force was measured on the main rubber side and the bonding rubber side under the following conditions. taking measurement.・ 180 ° T type peeling ・ Peeling speed 50mm / min ・ Measuring temperature 20 ℃ ・ Measurement item Peeling force (kgf / 25mm)

[0018] It can be seen from Table 3 that the peeling force is lowered when the amount of sulfur compounded in the joining rubber is less than 0.20% by weight.

[0019]

EXAMPLE A bonded structure was prepared in the same manner as in the above (6) with the blending amount of sulfur shown in Table 4 (Comparative Example, Example 1).
2), the breaking energy of the sulfur accumulation part and the breaking load of the product were measured. The results are shown in Table 4. Note) * Censored without breaking Table 4 shows that Examples 1 and 2 have higher product breaking loads and superior durability as compared with Comparative Examples.

[0020]

As described above, according to the present invention, since the relationship between the sulfur content of the vulcanized rubber part and the unvulcanized rubber part is determined, the vulcanized rubber having a required breaking load of 150 ton / m or more. -It becomes possible to improve the durability of the unvulcanized rubber bonded structure.

[Brief description of drawings]

FIG. 1 is a diagram showing a relationship between a required breaking load of a vulcanized rubber-unvulcanized rubber joint structure and a breaking energy of a sulfur accumulation portion.

FIG. 2 is a relationship diagram between the total amount of sulfur in a vulcanized rubber-unvulcanized rubber joint structure and the sulfur accumulation part breaking energy.

FIG. 3 is a diagram showing the relationship between the total amount of sulfur and the amount of compounded sulfur in the main rubber compound.

FIG. 4 is a graph showing the relationship between changes in the amount of sulfur blended in the main rubber and the amount of sulfur blended in the bonding rubber in the vulcanized rubber-unvulcanized rubber joint structure, and the energy at which sulfur accumulates at the accumulated portion.

FIG. 5 is a diagram showing the relationship between the amount of sulfur compounded with a bonding rubber and the amount of sulfur compounded with a main rubber in a vulcanized rubber-unvulcanized rubber bonded structure.

Claims (2)

[Claims] 1. The vulcanized rubber parts are joined together via unvulcanized rubber parts, the required breaking load is 150 ton / m or more, and the sulfur content x (% by weight) of the vulcanized rubber parts. And a sulfur content y (% by weight) of the unvulcanized rubber part has the following relationship: y ≦ −1.7x + 2.8 ・ ・ ・ ・ ・ ・ 0.2 ≦ y ≦ 1.65 ・ ・ ・ 2. The sulfur content x of the vulcanized rubber part is 0.7 to
The vulcanized rubber-unvulcanized rubber joint structure according to claim 1, which is 1.5% by weight.