JPH0675928B2 - Transmission belt - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a power transmission belt, and more specifically, to a heat-resistant aging property, and in addition, there is no deterioration or blooming of the fiber core wire and immediate adhesion to the fiber core wire. The present invention relates to a transmission belt having a rubber composition as a constituent member.

2. Description of the Related Art In recent years, demands for improving the life and reliability of transmission belts are increasing. As such a transmission belt, for example, a V belt is widely used in various fields, but in general, a V belt is used.
As shown in FIG. 1, the belt has a compression rubber layer 1 and an adhesive rubber layer 2 which are vulcanized and bonded together, and a fiber core wire 3 is adhesively embedded in the adhesive rubber layer 2. The canvas 4 is adhered over the entire circumference or on the front and back surfaces.

Conventionally, in the adhesive rubber layer, from the viewpoint of heat resistance and fatigue life, a polychloroprene compound is often used,
Further, as the core wire, a fiber core wire made of polyester or the like is used, but according to the conventional adhesive rubber, the adhesion between the fiber core wire and the adhesive rubber layer is not sufficient, or the adhesiveness is good. When the adhesive rubber is used, the fiber core wire deteriorates,
A crack is generated at the adhesive surface between the fiber core wire and the adhesive rubber layer,
It often reaches the end of its life, and there is a strong demand for improvement.

That is, generally, in order to bond the chloroprene rubber to the fiber core wire, a means of blending polychloroprene with sulfur or a thiuram vulcanization accelerator is used.
According to the method of compounding sulfur, although strong adhesion is achieved between the vulcanized chloroprene rubber and the fiber core wire, it reduces the heat deterioration resistance of the vulcanized rubber, while the compounding of the thiuram vulcanization accelerator Has a poorer effect of increasing the adhesiveness than sulfur. Therefore, when an amount effective for adhesion is added, deterioration of the polyester core wire is promoted, and further blooming occurs in the vulcanized rubber.

Thus, in order to improve the adhesion between the core wire and the adhesive rubber layer in the power transmission belt, for example, Japanese Patent Publication No. 63-28788
The publication proposes to use a rubber composition reinforced with hydrous silicic acid and carbon black for the above-mentioned adhesive rubber layer together with a silane coupling agent such as γ-mercaptopropyltrimethoxysilane.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention As a result of intensive studies to solve the above-mentioned problems in conventional transmission belts, the present inventors have suppressed the deterioration of heat-resistant deterioration of vulcanized rubber due to the incorporation of sulfur into polychloroprene. In order to limit the compounding amount of sulfur and to reduce the adhesiveness of the chlorobrene rubber accompanying it, a di, tri or tetrasulfide compound is compounded, and thus the obtained polychloroprene compound is used in the adhesive rubber layer. Therefore, in addition to being excellent in heat deterioration resistance, there is no deterioration of the fiber core wire or blooming of the vulcanization accelerator, and moreover, it is possible to obtain a transmission belt which has excellent adhesion to the fiber core wire and has a significantly improved life. The inventors of the present invention have found out what can be done and have reached the present invention.

Means for Solving the Problems A power transmission belt according to the present invention includes a compression rubber layer, an adhesive rubber layer,
In a transmission belt composed of a canvas and a fiber core wire, in which the fiber core wire is adhesively embedded in the adhesive rubber layer, (a) 0.3 to 1.5 parts by weight of sulfur, and (b) to 100 parts by weight of polychloroprene. A di-, tri-, or tetra-sulfide compound which has at least one -Sx- (wherein x is a number of 2 to 4) bond in the molecule and which does not generate a large amount of amine compound by its decomposition. The adhesive rubber layer made of a rubber composition containing 0.2 to 1.5 parts by weight of sulfur is vulcanized and adhered to the compressed rubber layer.

In the power transmission belt according to the present invention, the adhesive rubber layer is made of a vulcanized product of a polychloroprene compound containing sulfur and a di-, tri-, or tetra-sulfide compound. Sulfur is
In order to suppress the deterioration of the heat resistance and aging resistance of the adhesive rubber layer, the compounding amount thereof in the polychloroprene compound is limited, and it is compounded in the range of 0.3 to 1.5 parts by weight with respect to 100 parts by weight of polychloroprene. According to the present invention, in order to compensate for the decrease in the adhesiveness due to the decrease in the amount of sulfur, the polychloroprene compound for the adhesive rubber layer contains -Sx- (where x is 2 0.2 to 1.5 parts by weight as a sulfur amount of a di, tri or tetrasulfide compound which has at least one bond and does not generate a large amount of amine compound due to its decomposition. .

The amount of sulfur is 100 parts by weight of polychloroprene rubber,
When it is less than 0.3 parts by weight, strong adhesion cannot be achieved between the adhesive rubber layer and the fiber core wire, while 1.
When it exceeds 5 parts by weight, heat aging of the vulcanized rubber becomes remarkable. As sulfur, powdered sulfur, insoluble sulfur, colloidal sulfur and the like are used.

The sulfide compound used in the present invention should not be one that decomposes at the time of vulcanization of polychloroprene to generate a large amount of organic amine, such as a thiuram compound. As described above, when a large amount of organic amine is produced, the fiber core wire, particularly the fiber core wire made of polyester is deteriorated. Therefore, specific examples of the sulfide compound that can be preferably used in the present invention include:
For example, 4,4′-dithiobis (dimorpholine), 2-
Examples thereof include (4-morpholinodithio) benzothiazole, alkylphenol-sulfide resin, vinyl (triethoxysilylpropyl) tetrasulfide and the like.

The sulphide compound achieves strong adhesion between the adhesive rubber layer and the fiber core wire in the polychloroprene blend when the blending amount is less than 0.2 parts by weight with respect to 100 parts by weight of polychloroprene. On the other hand, if it exceeds 1.5 parts by weight, not only the effect of improving the adhesion between the adhesive rubber layer and the fiber core is saturated, but also the vulcanization speed and rubber elasticity are adversely affected. give.

On the other hand, the fiber core wire is previously treated with RFL containing a sulfur crosslinkable latex. Such RFL has already been usually used, and for example, vinylpyridine-styrene-butadiene latex and chloroprene latex are preferably used. Also, the fiber core wire is
In order to improve the adhesion with the adhesive rubber layer, for example, it may be pretreated with an epoxy resin or the like.

In the power transmission belt according to the present invention, the polychloroprene compound for forming the adhesive rubber layer may contain an additive that is usually compounded, in addition to the above-mentioned sulfur and sulfide compound. Examples of such additives include a reinforcing material such as carbon black, a filler such as calcium silicate, a softening agent, an antioxidant, a tackifier, and a crosslinking agent.

In the power transmission belt according to the present invention, the compressed rubber layer may be rubber conventionally used in the compressed rubber layer,
Usually, natural rubber, styrene-butadiene rubber, butadiene rubber, chloroprene rubber, etc. are used.

According to the present invention, by using the polychlorobrene compound as described above as the adhesive rubber layer, the adhesive rubber layer containing the fiber core wire and the compressed rubber layer are laminated by a usual method, and vulcanized. Therefore, a transmission belt can be obtained.

As described above, according to the present invention, a polychloroprene compound containing a predetermined amount of sulfur and a di, tri or tetrasulfide compound as an adhesive rubber layer for adhesively embedding a fiber core wire in a belt. By using, it is possible to obtain a transmission belt which is excellent in heat aging resistance and is also excellent in adhesion to the fiber core wire without deterioration of the fiber core wire or blooming.

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

As the fiber core, a polyester cord of 1000d / 2 × 3 was treated with an epoxy resin and then treated with RFL containing vinylpyridine-SBR latex.

The composition of the rubber compound is as follows. The number of parts indicates the number of parts by weight.

Polychloroprene 100 parts Carbon black 40 parts Calcium silicate 10 parts Plasticizer 5 parts Anti-aging agent 2 parts Stearic acid 2 parts Magnesium oxide 4 parts Zinc oxide 5 parts Sulfur (Table 1) Sulfide compounds (Table 1) Above polyester cord Were placed side by side between 3 mm-thick sheets made of the above-mentioned compound, and this was press-vulcanized at 150 ° C. for 30 minutes to prepare a test sample.

The sample was cut into 1 inch width in the cord direction, and the adhesive force between the cord and the adhesive rubber was measured. In addition, the above sample
After keeping in steam at 150 ℃ for 5 hours, take out the cord,
The tensile breaking strength was measured.

Furthermore, a vulcanized sheet of adhesive rubber alone was prepared and
According to the method described in K6301, after heating at 120 ° C. for 72 hours, the tensile elongation at break was measured. The results are shown in Table 1.

Next, using the polychloroprene blends of Comparative Examples 1, 2 and 5 and Examples 2 and 6 shown in Table 1 as an adhesive rubber layer, a low-edge belt A-40 (upper width 12.5 mm, height
We made a V-belt with 8.0mm, effective pitch 40 inches, and V-angle 40 °). This drive pulley (diameter 70mm) and driven pulley (diameter 70m)
m), load 80kg, pulley rotation 4900r
The belt was run at pm and the life of the belt was measured. The belt life was evaluated by the time required for the cord to start peeling at the adhesive surface between the lower portion of the cord and the adhesive rubber layer, and the time required for the cord peeling length to reach one half of the belt. The results are shown in Table 2.

The belt according to the present invention is shown to improve belt life by a factor of 3-4.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a normal V-belt. 1 ... Compressed rubber layer, 2 ... Adhesive rubber layer, 3 ... Fiber core wire, 4 ... Canvas.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display area // B29K 9:00

Claims (1)

[Claims] 1. A transmission belt comprising a compressed rubber layer, an adhesive rubber layer, a canvas and a fiber core wire, wherein the fiber core wire is adhesively embedded in the adhesive rubber layer.
(A) 0.3 to 1.5 parts by weight of sulfur, and (b) at least one -Sx- (wherein x is a number of 2 to 4) bond in the molecule, and An adhesive rubber layer made of a rubber composition containing 0.2 to 1.5 parts by weight of a di-, tri-, or tetra-sulfide compound, which does not generate a large amount of amine compound due to its decomposition, is vulcanized and adhered to the compression rubber layer. A transmission belt that is characterized by being.