JPH0517627A - Lubricating rubber composition and lubricating rubber molding made therefrom - Google Patents

Abstract

PURPOSE:To provide a lubricating rubber composition which can form a rubber molding which can exhibit sliding properties such as lubricating properties and abrasion resistance stably for a long time without detriment to sealability, strengths, vibration-damping properties and contour-following properties inherent in a rubber material and a lubricating rubber molding made therefrom. CONSTITUTION:A lubricating rubber composition which comprises 100 pts.wt. natural rubber and/or synthetic rubber [A], 10-150 pts.wt. synthetic resin powder [B], 5-40 pts.wt. lubricating oil [C] satisfying the relationship of ¦deltae-deltas¦>=1.0 (wherein deltae is the solubility parameter of rubber [A], and deltas is that of oil [C]. A lubricating rubber molding is prepared by vulcanizing and molding the above composition.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD OF THE INVENTION The present invention relates to a lubricating rubber composition and a lubricating rubber molding comprising the same, and more specifically,
The present invention relates to a lubricative rubber composition capable of forming a rubber molded article that can stably exhibit excellent sliding characteristics for a long period of time, and a lubricating rubber molded article composed of the same.

[0002]

BACKGROUND OF THE INVENTION Rubber materials have been widely used by being molded into sealing members and the like. Generally, a molded product obtained from a rubber material has a high friction coefficient and exhibits excellent adhesion and followability as a seal member, but on the other hand, it may cause so-called "squeaking" or stick-slip. If the rubber molded body is used for a long period of time in such a state, it will be abraded severely. Therefore, it is strongly desired to improve the sliding characteristics of the sealing material made of a rubber material.

In order to deal with such a problem, conventionally,
Various methods of reducing the coefficient of friction have been tried. For example, a method has been proposed in which powder of resin such as polytetrafluoroethylene (PTFE), polyacetal, or polyester is mixed into a rubber material forming a rubber molded body to impart lubricity to the rubber molded body. However, such a molded body made of a rubber material mixed with resin powder tends to have poor wear resistance when used as a sliding member.

Separately from this, a method has been proposed in which an oil such as polyethylene glycol is mixed to impart lubricity to the rubber material, and the rubber material is molded into a bleed-type sliding rubber member for use. However, in the bleed-type rubber molded body, the speed of bleeding (bleeding) of oil during use is high, and the bleeding oil is wiped off by the sliding member. For this reason,
Such a rubber molded product has a large friction coefficient in a short period of time and has a short life.

For this reason, a rubber capable of forming a rubber molding which can exhibit excellent sliding characteristics for a long period of time without impairing the sealability, followability, vibration damping and strength inherent in the rubber material. The advent of materials is desired.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned prior art, and does not impair the sealability, strength, vibration damping property, and followability that rubber materials originally have, and can be used for a long period of time. An object of the present invention is to provide a lubricative rubber composition capable of forming a rubber molded article which can be stabilized over a period of time and can exhibit sliding characteristics such as lubricity and wear resistance, and a lubricious rubber molded article comprising the same.

[0007]

SUMMARY OF THE INVENTION The lubricating rubber composition according to the present invention comprises
[A] natural rubber and / or synthetic rubber; 100 parts by weight; [B] synthetic resin powder; 10 to 150 parts by weight,
[C] A lubricating oil having a solubility parameter δs satisfying the following formula [I] between the solubility parameter δe and the solubility parameter δe of the rubber [A]; 5
˜40 parts by weight.

| Δe −δs | ≧ 1.0 ... [I] Further, the lubricating rubber molded article according to the present invention is characterized by being vulcanized and molded from the above-mentioned lubricating rubber composition. .

[0009]

DETAILED DESCRIPTION OF THE INVENTION First, the lubricating rubber composition according to the present invention will be specifically described. As the [A] natural rubber or synthetic rubber forming the lubricating rubber composition according to the present invention, any rubber that can have a crosslinked structure after vulcanization molding may be used, and commonly known rubbers are widely used. You can come. Specifically, in addition to natural rubber (NR), the following synthetic rubbers can be given as examples.

Isoprene rubber (IR), butadiene rubber (BR), styrene-butadiene rubber (SBR), chloroprene rubber (CR), nitrile rubber (NBR), butyl rubber (IIR, BIIR, CIIR), ethylene-propylene rubber (EPM, EPDM), chlorosulfonated polyethylene (CSM), acrylic rubber (ACM, AE)
M), epichlorohydrin rubber (CO, ECO), polysulfide rubber (OT, EOT), fluororubber (FKM, FFK)
M, FZ, AFMU, CFM), urethane rubber (AU,
EU), Silicone rubber (MQ, VMQ, PMQ, FV
MQ, PVMQ), chlorinated polyethylene rubber (CM),
Ethylene-vinyl acetate copolymer rubber (EAM), polypropylene oxide-aryl glycidyl ether rubber (GPO), acrylic-butadiene rubber (ABR), acrylonitrile-chloroprene rubber (NCR), acrylonitrile-isoprene rubber (NIR), vinylpyridine-butadiene Rubber (PBR), vinylpyridine-styrene-butadiene rubber (PSBR), styrene-chloroprene rubber (SCR), styrene-isoprene rubber (S
IR), PZ (having P = N chains and having an allyloxy group bonded to the P atom) rubber and the like.

Further, these rubbers may be hydrogenated rubbers, for example, hydrogenated nitrile rubbers (NEM), in which some of the double bonds in the molecule are hydrogenated. Further, the above rubber is modified with a carboxyl group,
For example, carboxylated nitrile rubber (X-NB
R), carboxylated styrene butadiene rubber (X-S
BR).

These rubbers may be used alone or in combination. Next, the [B] synthetic resin powder that forms the lubricating rubber composition will be described. Examples of such synthetic resin powders include powders made of the following synthetic resins.

Polytetrafluoroethylene, polyethylene terephthalate, polybutylene terephthalate, polyacetal, ultra high molecular weight polyethylene, polyimide, polyamide imide, polyether ether ketone, polyphenylene sulfide, polyether imide, polyether sulfone, polyarylate, polyphenylene oxide, polyamide , Polycarbonate, etc.

These can be used alone or in combination. Of these, polytetrafluoroethylene is preferably used. The [B] synthetic resin powder used in the present invention has an average particle size of 0.5 to 50 μm.
m, preferably 3 to 30 μm.

The lubricating rubber composition according to the present invention contains 10 to 150 parts by weight, preferably 10 parts by weight of the synthetic resin powder [B], when the amount of the rubber [A] is 100 parts by weight.
˜100 parts by weight.

Next, the lubricating oil [C] forming the lubricating rubber composition according to the present invention will be described. The lubricating oil [C] used in the present invention has a solubility parameter δs satisfying the following formula [I] between the solubility parameter δe and the solubility parameter δe of the rubber [A]. Oil is used.

| Δe−δs | ≧ 1.0 ... [I] Here, the solubility parameter (SP value: δ) is the square root of the cohesive energy density of the substance.

When .vertline..delta.e-.delta.s.vertline. =. DELTA..delta., The closer the .delta..delta. That is, as described above, the [A] rubber and the [C] lubricating oil are compatible with each other when the substances having the solubility parameters δe and δs closer to each other.
Usually, the boundary between compatibility and insolubility is that the Δδ value is 1.1.

The lubricating oil [C] used in the present invention has a solubility parameter difference Δ with the rubber [A].
The relationship that δ is 1.0 or more is satisfied. Δδ
[C] Lubricating oil with [A] less than 1.0
It becomes compatible with rubber, and the composition obtained from such components cannot exhibit lubricity as a bleed type rubber material.

Specific examples of such a lubricating oil include liquid paraffin, silicone oil, fluorinated oil, ester oil, mineral oil, polyalkylene glycol oil and the like.

In the lubricating rubber composition according to the present invention, such a lubricating oil [C] is contained (blended) in an amount of 5 to 40 parts by weight based on 100 parts by weight of the rubber [A]. . In the lubricating rubber composition according to the present invention, since the [B] synthetic resin powder and the [C] lubricating oil are contained (blended) in the above amounts, the rubber material originally has The impact resistance, compression set resistance, resilience, strength, and other properties of the elastic body are not impaired, and the friction coefficient is reduced to provide lubricity, wear resistance is improved, and sliding It becomes possible to form a rubber molding having improved properties.

In the rubber composition in which the synthetic resin powder [B] and the lubricating oil [C] are blended in an amount less than the above, the wear resistance is not improved so much and the lubricity is not imparted so much. In addition, the rubber composition in which both are blended in an amount exceeding the above amount has impact resilience inherent in rubber, compression set resistance, restoring property,
It tends to impair various properties of the elastic body such as strength.

The lubricating rubber composition according to the present invention usually contains (blends) a vulcanizing agent. The vulcanizing agent used in the present invention, widely known vulcanizing agent can be widely used, sulfur, magnesium oxide, zinc white, quinoid vulcanizing agent, peroxide vulcanizing agent, Examples thereof include amine vulcanizing agents, resin vulcanizing agents, organic sulfur vulcanizing agents, and the like.

These vulcanizing agents are usually [A] rubber 10
0.1 to 10 parts by weight, preferably 0.1 to 0 parts by weight.
It is blended in an amount of 3-4. In addition, a vulcanization aid, a vulcanization accelerator and the like may be blended in the above-mentioned lubricating rubber composition.

As such a vulcanization aid, compounds generally known as vulcanization aids such as zinc white and stearic acid can be widely used. Such a vulcanization aid is usually used in an amount of 0.5 to 100 parts by weight of the rubber [A].
It can be blended in an amount of 10 parts by weight.

As the vulcanization accelerator, guanidine compounds, sulfenamide compounds, thiuram compounds, dithiocarbamate compounds, aldehyde-amine compounds, thiourea compounds, xanthate compounds,
Compounds generally known as vulcanization accelerators such as aldehyde-ammonia compounds can be widely used.

The lubricating rubber composition according to the present invention may further contain, if necessary, the following fillers and additives as long as the object of the present invention is not impaired. As such a filler, compounds generally known as fillers can be widely used.

For example, carbon black, silica, calcium carbonate, clay (aluminum silicate), magnesium carbonate, talc (magnesium silicate), wollastonite, aluminum hydroxide, aluminum sulfate, barium sulfate, calcium sulfate, mica, graphite, Cellulose powder etc. can be mentioned.

The filler can be usually used in an amount of 5 to 150 parts by weight with respect to 100 parts by weight of the rubber [A]. In addition, as the additive, additives generally used as rubber chemicals such as an antiaging agent, a flame retardant, a colorant, a processing aid, an antistatic agent and a plasticizer can be widely used.

Examples of antiaging agents include naphthylamine antiaging agents, diphenylamine antiaging agents, quinoline antiaging agents, monophenol antiaging agents, and special waxes.

The antioxidant may be usually contained (blended) in an amount of 0.5 to 3 parts by weight with respect to 100 parts by weight of the lubricating rubber composition. The lubricative rubber molding according to the present invention is obtained by vulcanizing and molding the above-mentioned lubricative rubber composition.

At the time of vulcanization molding, generally, a lubricating rubber composition comprising the above components is kneaded to obtain a kneaded product, which is vulcanized and molded. In kneading, the order of adding the above-mentioned components is not limited.

The kneading can be carried out by using a usual rubber kneading apparatus, for example, a kneader, a Brabender mixer, a Banbury mixer, a roll mixer or the like.

Such kneading is usually carried out in the range of 20 to 120.
5 to 30 minutes at a temperature of 50 ° C, preferably 50 to 80 ° C.
It is preferably carried out for 10 to 20 minutes. Next, the kneaded product obtained as described above is vulcanized and molded under heating to obtain a lubricious rubber molded body.

In the vulcanization molding, specifically, the kneaded product is filled in a mold having a desired shape, and the temperature is 140 to 230 ° C., preferably 150 to 180 ° C. for 3 to 60 minutes, preferably 10 to 30 ° C.
It is performed by heating for 30 minutes.

As the lubricative rubber molding thus obtained, for example, a sealing material for sliding parts such as packing can be preferably mentioned. In a conventional bleed-type rubber molded body obtained by molding a rubber material mixed with oil, the bleeding speed of the oil is high, and the oil mixed in a short period of time tends to exude to the surface of the molded body.
In such a rubber molded product, the exuded oil is wiped off by the mating (sliding) material, so that the friction coefficient increases and the lubricity decreases in a short period of time.

On the other hand, in the molded product obtained from the lubricating rubber composition according to the present invention, the lubricating oil contains the [B] synthetic resin powder and the [C] lubricating oil. It does not immediately exude from the molded product, and the bleed speed is controlled.

Therefore, when the lubricative rubber molding obtained in the present invention is used as a seal member for a sliding portion, good lubricity is exhibited for a long period of time at the contact surface with the mating (sliding) member. The sticking phenomenon is unlikely to occur.

Such a lubricative rubber molding according to the present invention, when used as, for example, a seal member or the like, exhibits excellent sealing properties, followability, vibration damping properties and mechanical strength of the rubber material body. At the same time, since lubricity is also exhibited, it is possible to prevent so-called squeaking phenomenon and stick-slip of the device.

[0040]

EFFECTS OF THE INVENTION According to the present invention, it is possible to form a rubber molded article which is excellent in the sealing property, the followability, the vibration damping property and the mechanical strength which the rubber material originally has, and which is also provided with the lubricity.

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

[0042]

Examples 1 to 4 Compositions shown in Table 1 were obtained. This composition was kneaded with an open roll for 20 minutes and vulcanized at 160 ° C. for 20 minutes under pressure to obtain a lubricious rubber molding.

Table 1 shows the physical properties of the obtained molded product. The physical properties were measured as follows. Friction and wear characteristics:
It measured on the following conditions using the thrust type friction tester.

Counterpart material: SS41 PV value = 3.2 MPa · cm / sec Normal physical properties were measured according to JIS K6301.

[0045]

Comparative Examples 1 to 3 The compositions shown in Table 1 were obtained. This composition was treated in the same manner as in Example 1 to obtain a lubricious rubber molding.

Table 1 shows the physical properties of the obtained molded product. Further, these molded products were tested for the amount of oil bleed. In the test, after the molded body was left in a desiccator for 6 hours, the surface of the molded body was wiped off and the weight before and after wiping was measured to obtain the weight change before and after wiping.

[0047]

[Table 1]

[0048]

Example 5 The composition shown in Table 1 was kneaded in the same manner as in Example 1, vulcanized at 170 ° C. for 20 minutes under pressure and vulcanization molded to obtain a molded body.

Table 1 shows the frictional wear characteristics and normal physical properties of the obtained molded product.

[0050]

[Comparative Example 4] A molded product was obtained from the composition shown in Table 1 in the same manner as in Example 5. Table 1 shows the frictional wear characteristics and normal physical properties of the obtained molded product.

The compositions of Example 5 and Comparative Example 4 were molded into packing as follows. 170 with a given mold
Vulcanization molding was performed under pressure at 20 ° C. for 20 minutes to mold the packing having the shape shown in FIG.

The packing was subjected to a life test as a robot joint seal material. The test was conducted under the conditions of test pressure: 7 Kgf / cm ² (Air), speed: 100 cpm, motion type: 330 ° forward / reverse rotational motion, sliding part: packing upper surface. The test results are shown in FIG.

From the test results, it is clear that Example 5 has a much longer life than Comparative Example 4.

[Brief description of drawings]

FIG. 1 shows a cross section of a packing used for a life test as a robot joint seal material.

FIG. 2 is a graph showing a life test result of packing.

Claims (2)

[Claims] 1. [A] Natural rubber and / or synthetic rubber;
100 parts by weight, [B] synthetic resin powder; 10 to 150 parts by weight, and [C] When the solubility parameter of the [A] rubber is δe, the following formula [I] is obtained between the solubility parameter δe. Lubricating oil with a solubility parameter δs satisfying 5
To 40 parts by weight of the lubricating rubber composition. │δe −δs │ ≧ 1.0 ... [I] 2. [A] Natural rubber and / or synthetic rubber;
100 parts by weight, [B] synthetic resin powder; 10 to 150 parts by weight, and [C] When the solubility parameter of the [A] rubber is δe, the following formula [I] is obtained between the solubility parameter δe. Lubricating oil with a solubility parameter δs satisfying 5
A lubricative rubber molded body obtained by vulcanizing and molding a lubricious rubber composition comprising about 40 parts by weight. │δe −δs │ ≧ 1.0 ... [I]