JPH0349931B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vulcanized rubber having a low friction sliding surface.

Noise and alignment when using a transmission V-belt are related to the surface friction resistance of the belt's sliding surface.
By reducing the coefficient of friction, noise can be reduced and alignment properties can be improved. For this reason, for example, attempts have been made to soak the belt in a lubricating agent such as silicone oil prior to its use, but this treatment prevents the particles from sticking to the belt surface as a result of use of the belt. Since the silicone oil containing the belt quickly scatters, the effect of reducing the friction coefficient of the belt sliding surface quickly disappears and is not maintained over a long period of time.

On the other hand, since silicone oil has poor compatibility with rubber, the amount that can be directly kneaded with unvulcanized rubber is generally limited. Bleeding to the surface is significant, causing the belt surface to become sticky, which in turn reduces the belt's functionality and product value.

Furthermore, it is not easy to directly knead silicone oil, which has poor compatibility with rubber, into rubber, and especially as the amount of silicone oil added to rubber increases, for example, in the most common kneading process using rolls, rubber The roll operability becomes extremely poor, such as slipping on the top or coming off the roll, and it is not possible to uniformly disperse the rubber into the rubber. As a result, the vulcanized rubber obtained from such an unvulcanized rubber composition lacks stability in quality, and due to severe bleeding of silicone oil, it is not effective in reducing the coefficient of friction of the belt sliding surface. Disappears in a short period of time.

The present invention has been made to solve the various problems described above, and the lubricating agent, which originally has poor compatibility with rubber, is adsorbed to porous particles and dispersed uniformly within the rubber. vulcanization, in which the lubricating agent bleeds into the rubber surface at a small, substantially constant rate over time, such that the rubber surface has a small, substantially constant coefficient of friction over time. An object of the present invention is to provide a rubber, that is, a vulcanized rubber having a bottom friction sliding surface.

The vulcanized rubber having a low-friction sliding surface according to the present invention is produced by adsorbing 1 to 10 parts by weight of a lubricating agent selected from silicone oil and fluorine compounds on porous particles per 100 parts by weight of rubber. It is characterized by being made of a vulcanized rubber compounded rubber composition.

In the vulcanized rubber according to the present invention, the lubricating agent refers to a compound that migrates to the rubber surface due to its poor compatibility with the rubber, reduces its frictional resistance, and makes the surface lubricated; Preferably, silicone oil is used, but in addition to this, fluorine compounds can also be used as a lubricating agent, and such lubricating agents include:
It is blended into rubber either as a solution dissolved in an appropriate organic solvent or as an aqueous emulsion and adsorbed onto porous particles.

In the rubber industry, it is common practice to blend mineral oil into rubber as a process oil or softener. However, process oils and softeners inherently have good compatibility with rubber, and are used to uniformly disperse in rubber and soften the rubber to improve its processability. Do not migrate to the surface. On the other hand, when the lubricating agent used in the present invention is blended with rubber, it deteriorates processability such as roll operability and is likely to migrate to the rubber surface.

According to the present invention, by adsorbing a lubricating agent with poor compatibility with rubber into porous particles, the workability of the lubricating agent when kneading with rubber is not deteriorated. The transfer to the rubber surface is controlled, so to speak, for sustained release. Therefore, the lubricating agent in the present invention has a different purpose and function from a process oil or a softening agent, and should be distinguished from these.

In the present invention, the porous particles for adsorbing the lubricating agent as described above have an average particle size of
Inorganic porous particles in the range of 1 μm to 30 μm, preferably 10 μm to 25 μm are preferably used. Preferred specific examples of such inorganic porous particles include activated carbon, diatomaceous earth, and synthetic hydrated calcium silicate. In the present invention, activated carbon having an average particle size of 1 to 100 μm, diatomaceous earth having an average particle size of 10 to 30 μm, and synthetic hydrated calcium silicate having an average particle size of 1 to 5 μm are particularly preferably used.

In order to make such porous particles adsorb a lubricating agent, both may be mixed by a conventional method, for example, a method using an internal blender. When the lubricating agent is the above-mentioned fluorine compound, the solution or emulsion is mixed with the porous particles and then dried to remove the solvent.

The amount of the lubricating agent adsorbed onto the porous particles depends on the type of porous particles and lubricating agent used, but is usually 100 to 1000 parts by weight per 100 parts by weight of the porous particles.
Preferably it is 200 to 500 parts by weight.

The porous particles on which the lubricating agent has been adsorbed in this manner can be kneaded into unvulcanized rubber by conventional kneading means such as kneading rolls, Banbury mixers, intermixers, and spar mixers.

Rubbers include natural rubber, styrene-butadiene rubber, butadiene rubber, chloroprene rubber, ethylene-propylene-diene rubber, butyl rubber,
Isobutylene rubber, nitrile rubber, chlorosulfonated polyethylene rubber, polysulfide rubber,
Silicone rubber, urethane rubber, acrylic rubber, etc. are used.

The amount of the lubricant added to the unvulcanized rubber may range from 1 to 10 parts by weight per 100 parts by weight of the unvulcanized rubber, preferably from 2 to 8 parts by weight, particularly preferably from 3 to 8 parts by weight. 6 parts by weight. If the amount of the lubricant is too small, the resulting vulcanized rubber surface will be insufficiently lubricated and will not be effective in reducing surface frictional resistance. This is because a lubricating agent with poor compatibility may bleed excessively onto the rubber surface, which is undesirable.

In the present invention, the unvulcanized rubber composition is usually
It may contain a vulcanizing agent, a vulcanization accelerator, an anti-aging agent, a reinforcing agent, a filler, a lubricant, etc. that are mixed into the rubber. Porous particles adsorbed with a lubricating agent may be mixed into the unvulcanized rubber together with these compounded chemicals and reinforcing agents, or they may be mixed into the unvulcanized rubber in advance. After blending chemicals, reinforcing agents, fillers, etc., porous particles adsorbed with a lubricant may be kneaded.

The vulcanized rubber according to the present invention can be obtained by vulcanizing such an unvulcanized rubber composition according to a conventional method.

The vulcanized rubber according to the present invention is produced by adsorbing a lubricating agent, which originally has poor compatibility with rubber, into porous particles, uniformly dispersing it within the rubber, and vulcanizing the unvulcanized rubber. This is what you get. Therefore, in such vulcanized rubber, bleeding of the lubricating agent onto the surface occurs at a substantially constant and small rate over a long period of time, and as a result, the vulcanized rubber surface remains lubricant over a long period of time. , has a substantially constant and small coefficient of friction.

Therefore, the vulcanized rubber according to the present invention is suitable for power transmission V-belts, etc., and such power transmission V-belts are
Noise during use is suppressed and alignment is improved. In addition, it is difficult to directly knead liquid chemicals such as silicone oil with poor compatibility with rubber, but according to the present invention, since they are adsorbed on porous particles, kneading can be done easily. It can be easily carried out by a conventional method and can be blended in large amounts.

The present invention will be explained below with reference to Examples, but the present invention is not limited to these Examples in any way. In addition, in the following, parts indicate parts by weight.

Example 1 10 parts of synthetic hydrated calcium silicate (Micro-Cel, manufactured by John Manville) with an average particle size of 2.7 μm was mixed with 30 parts of silicone oil (KM722, manufactured by Toshiba Silicon Co., Ltd.), and a slightly moist powder was prepared. Obtained.

Separately, neoprene GRT (manufactured by Showa Neoprene Co., Ltd.)
500 parts of stearic acid, 5 parts of magnesia, 25 parts of zinc white No. 3, 5 parts of octylated diphenylamine, and 250 parts of carbon FEF were kneaded with a roll, and the powder obtained above was added to this kneaded rubber, and kneaded with a roll. An unvulcanized rubber composition was obtained.

After cutting this unvulcanized rubber composition into predetermined dimensions,
It was mounted in a Williams abrasion test mold and vulcanized for 3 minutes at a temperature of 148°C to obtain a vulcanized rubber test piece. After abrading this test piece with a Williams abrasion tester under a load of 2.6 kg, the polished surface was replaced with an iron piece, and the test piece weighed 4.1 kg.
Surface abrasion resistance was measured under load. The figure shows the relationship between the rotation speed of the polished surface and the frictional resistance of the test piece.

As a comparative example, 500 parts of the above kneaded rubber and silicone oil were used.
After directly kneading 30 parts with a roll, a vulcanized rubber test piece was obtained in the same manner. However, kneading was extremely difficult and required 1.5 times the time as described above due to inconveniences such as the rubber coming off the rolls. This test piece was also vulcanized in the same manner as above, and the relationship between the number of rotations of the polished surface and the frictional resistance of the test piece is shown in the drawing.

As is clear from the results shown, the surface frictional resistance of the vulcanized rubber according to the present invention maintains a substantially constant and small value over a long period of time. On the other hand, the vulcanized rubber according to the comparative example had silicone oil bleeding on the surface, and the surface friction resistance rapidly increased.

Example 2 A water emulsion of a fluorine compound (Freely 20 manufactured by Neos Co., Ltd.) was mixed with 10 parts of activated carbon with an average particle size of 50 mμ to obtain a moist powder in which 20 parts of a fluorine compound was adsorbed to the activated carbon. . After drying this in a dryer at 100° C. for 4 hours, it was added to the same neoprene rubber kneading as in Example 1 and kneaded with rolls to obtain an unvulcanized rubber composition.

This unvulcanized rubber composition was vulcanized in the same manner as in Example 1 to obtain a vulcanized rubber test piece. Regarding this test piece, the surface abrasion resistance was measured in the same manner as in Example 1. As with the vulcanized rubber of Example 1,
It had a nearly constant coefficient of friction over a long period of time.

[Brief explanation of drawings]

The drawing is a graph showing the relationship between the number of rotations of the polished surface measured by a Williams abrasion tester and the surface friction resistance of vulcanized rubber obtained from the rubber composition of the present invention, together with comparative examples.

Claims (1)

[Scope of Claims] 1. A rubber composition in which 1 to 10 parts by weight of a lubricating agent selected from silicone oil and fluorine compounds is adsorbed to porous particles and blended into rubber, based on 100 parts by weight of rubber. A vulcanized rubber comprising a low-friction sliding surface, characterized in that the lubricating agent bleeds onto the surface at a substantially constant and small rate. 2 For 100 parts by weight of porous particles, 100 parts by weight of lubricating agent
The vulcanized rubber having a low-friction sliding surface according to claim 1, wherein ~1000 parts by weight is adsorbed.