JPH05262919A - Short fiber-reinforced rubber composition and transmission belt using the same - Google Patents

Abstract

PURPOSE:To provide the subject composition excellent in wear resistance and reduced in offensive noise generation, incorporated with a combination of surface property-modified organic short fibers and surface property-unmodified organic short fibers, and to provide transmission belts using this composition. CONSTITUTION:The objective rubber composition incorporated with (A) organic short fibers 6 put to surface adhesive treatment and (B) organic short fibers 6 put to no such treatment at the weight ratio A/B of (20:80) to (80:20).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a short fiber reinforced rubber composition in which organic short fibers are mixed as a reinforcing material and a transmission belt using the same, and more particularly to measures for improving wear resistance and reducing abnormal noise. It is a thing.

[0002]

2. Description of the Related Art Conventionally, for example, a V as a transmission belt is used.
In a ribbed belt, in order to improve the lateral pressure resistance and abrasion resistance of the rib portion, it is common to mix organic short fibers into the rib rubber to improve the elastic modulus in the belt width direction. In this case, if a large amount of short fibers is mixed, the elastic modulus is improved and the lateral pressure resistance and the wear resistance are improved, but the dynamic bending fatigue resistance is deteriorated. Short fibers having a high elastic modulus have been used so that a high elastic modulus can be obtained. From this, the short fibers mixed in the rubber of the power transmission belt such as the V-ribbed belt have changed from cotton to nylon short fibers and polyester short fibers to aramid short fibers.

[0003]

However, since organic short fibers such as aramid short fibers are fragile against compression and shearing forces, they easily break off from the surface due to fibrillation and breakage, resulting in poor wear resistance.

Therefore, it was found that when the organic short fibers were subjected to the surface adhesion treatment, the abrasion resistance was improved. However, the short fibers were rubbed on the rubber surface as compared with the organic short fibers which were not subjected to the surface adhesion treatment. Is not exposed so much that the coefficient of friction becomes high, causing chattering with the pulley and causing abnormal noise.

The present invention has been made in view of the above points, and an object thereof is to use organic short fibers such as aramid short fibers whose surface properties are modified and unmodified. In view of the above, it is an object to provide a short fiber reinforced rubber composition having excellent wear resistance and capable of reducing abnormal noise, and a transmission belt using the same.

[0006]

In order to achieve the above object, a first solution of the present invention is that a short fiber reinforced rubber composition is surface-adhered with organic short fibers, That is, organic short fibers which have not been applied are mixed as a reinforcing material.

According to a second solution of the present invention, in the first solution, the organic short fibers which have been subjected to the surface adhesion treatment and the organic short fibers which have not been subjected to the surface adhesion treatment are mixed with respect to the total fiber amount. The ratio is 20-80% of the former and 8 for the latter.
It is set to 0 to 20%.

A third solution of the present invention is a belt made of a rubber composition in which organic short fibers which have been subjected to surface adhesion treatment and organic short fibers which have not been subjected to surface adhesion treatment are mixed as a reinforcing material. That is, it is used for at least a part of the constituent rubber portion.

According to a fourth solution of the present invention, in the third solution, the mixing of the total amount of the organic short fibers which have been subjected to the surface adhesion treatment and the organic short fibers which have not been subjected to the surface adhesion treatment is mixed. The ratio is 20-80% of the former and 8 for the latter.
It is set to 0 to 20%.

[0010]

With the above structure, in the first to fourth means for solving the problems of the present invention, the organic short fibers which have been subjected to the surface adhesion treatment and the organic short fibers which have not been subjected to the surface adhesion treatment are mixed as a reinforcing material. , The mixing ratio of the total amount of these fibers is 2 of the former.
Since the latter is set to 80 to 20% with respect to 0 to 80%, one of the defects is compensated by the merit of the other, fibrillation failure is less likely to occur, wear resistance is improved, and the friction coefficient is This reduces noise and makes it difficult for abnormal noise to occur.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a V-ribbed belt 1 as a transmission belt. The V-ribbed belt 1 has an upper canvas layer 2 formed by laminating rubber-coated canvas in order from the upper side, and an adhesive rubber layer 4 in which a tensile body 3 is embedded. , And the rib rubber layer 5 are integrally laminated. A predetermined amount of organic short fibers 6 such as aramid short fibers or polyester short fibers are mixed as a reinforcing material in the rib rubber layer 5 as the rubber portion constituting the belt. The organic short fibers 6 include those that have been subjected to a surface adhesion treatment and those that have not been subjected to a surface adhesion treatment. The mixing ratio with respect to the total amount of these fibers is 20 to 80% of the former. On the other hand, the latter is set to 80 to 20%.

As described above, the mixing ratio of the organic short fibers 6 which have been subjected to the surface adhesion treatment and the organic short fibers 6 which have not been subjected to the surface adhesion treatment is 20 to 80% of the former and 80 to the latter. The setting of 20% is based on the data of the wear amount and the friction coefficient and the mixing ratio of the organic short fibers 6 shown in FIG.

As a result, one drawback can be compensated by the other advantage, fibrillation failure can be made less likely to occur and wear resistance can be improved, and the friction coefficient can be reduced so that abnormal noise can be made less likely to occur. it can.

Next, an example of the present invention will be specifically described.

(Example 1) Acrylonitrile and 1,3-
Hydrogenated acrylonitrile butadiene rubber obtained by hydrogenating a copolymer with butadiene (hereinafter abbreviated as H-NBR); 100 phr, zinc methacrylate; 40 phr, organic peroxide; Polyester short fibers were mixed as shown in Table 1 to obtain an unvulcanized rubber sheet by a known method. As a bonding treatment for these organic short fibers, an isocyanate subcoat and a CR glue rubber topcoat were applied. This unvulcanized rubber sheet was heated at a predetermined temperature for a predetermined time to obtain a vulcanized rubber sheet. The amount of wear and the coefficient of friction of this vulcanized rubber sheet after 4 hours were measured by a friction and wear tester according to the following procedure, and the results are shown in Table 1.

<Measurement Procedure of Abrasion Amount> Pressure: 863 KPa, speed: 0.15 m / sec by pin disk method
The temperature was 25 ° C.

<Measurement Procedure of Friction Coefficient> A V-ribbed belt 1 was produced using the above-mentioned unvulcanized rubber sheet, and one end of the V-ribbed belt 1 was connected to a load cell 7 as shown in FIG. 8 (diameter 60 mm, rotation speed 43 rpm
), And the weight 9 (load T2 =
1.75 kgf) were connected, the load T1 acting on the load cell 7 was measured, and the friction coefficient μ was calculated by the following formula.

Μ = {ln (T1 / T2)} / (π / 2)

[Table 1]

Further, when the peeling force of the fiber was examined by the following procedure, it was 18 kgf / 3 for the aramid short fiber and 27 kgf / 3 for the polyester short fiber. The reason for using three fibers is that one fiber has a small peeling force and lacks reliability.

<Peeling force measurement procedure>
-A test scale embedded in NBR compound and vulcanized at 170 ° C for 30 minutes was pulled using a peeling tester to obtain a speed of 100
The peel adhesion strength was measured in mm / min.

Further, the sound level was measured at three stages of initial, 1 hour, and 3 hours, and the results are shown in Table 1.

As a result, Examples 1 and 2 of the present invention are Comparative Examples 2 and 3 in which only the organic short fibers to which the adhesion treatment is applied are mixed in the abrasion amount.
4 and less than Comparative Examples 1 and 3 in which only the organic short fibers not subjected to the adhesion treatment were mixed, but the coefficient of friction was, on the contrary, Comparative Example 2 in which only the organic short fibers to which the adhesion treatment was applied were mixed. It was lower than 4 and higher than those of Comparative Examples 1 and 3 in which only the organic short fibers not subjected to the adhesion treatment were mixed. The sound levels of Examples 1 and 2 of the present invention were higher than those of Comparative Examples 1 and 3 and lower than those of Comparative Examples 2 and 4.

(Example 2) A V-ribbed belt 1 was prepared using the same unvulcanized rubber sheet as in Example 1, and the rate of change in weight and the coefficient of friction after 24 hours in a belt running wear test were measured by the following procedure. The results are shown in Table 2.

<Measurement Procedure of Rate of Weight Change> As shown in FIG. 4, the V-ribbed belt 1 is wound around the two pulleys 10 and 10, the pulley rotation speed is 5100 rpm, and the dead weight is 1.
The weight change rate after running for 24 hours under the conditions of 20 kgf, load; 5.2 PS was measured.

<Measurement Procedure of Friction Coefficient> The measurement procedure was the same as in Example 1.

[0027]

[Table 2]

The sound level is set at the beginning, 24 hours later, and 12
Measurement was carried out at 3 stages after 0 hours, and the results are shown in Table 2. In Table 2, "absent" means that no abnormal noise is generated in the belt, and "present" means that abnormal noise is generated in the belt.

As a result, Examples 1 and 2 of the present invention have a higher weight change rate than Comparative Examples 2 and 4 in which only the organic short fibers to which the adhesion treatment is applied are mixed, and only the organic short fibers to which the adhesion treatment is not applied are included. Although the amount of friction was less than in Comparative Examples 1 and 3, the friction coefficient was lower than that of Comparative Examples 2 and 4 in which only the adhesive-treated organic short fibers were mixed. It was higher than the mixed Comparative Examples 1 and 3.
In the evaluation of the sound level, no abnormal noise was generated in the belts in Inventive Examples 1 and 2 and Comparative Examples 1 and 3, but in Comparative Examples 2 and 4, abnormal noise was generated in the belt after 24 hours and 120 hours. was there.

[0030]

As described above, according to the present invention according to claims 1 to 4, the organic short fibers which have been subjected to the surface adhesion treatment and the organic short fibers which have not been subjected to the surface adhesion treatment are reinforced. It is mixed as a material, and the mixing ratio with respect to the total amount of these fibers is set to 20 to 80% of the former and 80 to 20% of the latter, so that one defect can be compensated by the merit of the other and improvement of wear resistance and Reduction of friction coefficient (prevention of abnormal noise)
Can be planned.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a V-ribbed belt.

FIG. 2 is a data diagram showing the relationship between the wear amount and friction coefficient and the mixing ratio of organic short fibers.

FIG. 3 is a diagram illustrating a procedure for measuring a friction coefficient.

FIG. 4 is a diagram illustrating a procedure for measuring a weight change rate due to running of a belt.

[Explanation of symbols]

 1 V Ribbed Belt (Transmission Belt) 5 Rib Rubber Layer (Belt Constituent Rubber Part) 6 Organic Short Fiber

Claims (4)

[Claims] 1. An organic short fiber subjected to a surface adhesion treatment,
A short fiber reinforced rubber composition, wherein organic short fibers which have not been surface-adhered are mixed as a reinforcing material. 2. Organic short fibers that have been subjected to a surface adhesion treatment,
The mixing ratio of the organic short fibers not surface-adhered to the total amount of fibers is set to 20 to 80% for the former and 80 to 20% for the latter. Short fiber reinforced rubber composition. 3. Organic short fibers that have been subjected to a surface adhesion treatment,
A transmission belt, wherein a rubber composition in which organic short fibers which have not been subjected to surface adhesion treatment are mixed as a reinforcing material is used for at least a part of a belt-constituting rubber portion. 4. An organic short fiber subjected to a surface adhesion treatment,
4. The mixing ratio of the organic short fibers not subjected to the surface adhesion treatment to the total amount of fibers is set to 20 to 80% of the former and 80 to 20% of the latter, and the mixing ratio of claim 3 is characterized. Transmission belt.