RUBBER COMPOSITION

Abstract

A rubber composition comprising 0.1 to 2.5 parts by weight of a lubricant having a flow temperature of 50 to 100° C. based on 100 parts by weight of an ethylene/butene/5-ethylidene-2-norbornene terpolymer. This rubber composition is compounded with a specific lubricant, has the following effects. That is, the rubber composition prevents difficulties caused by sticking between unvulcanized rubber compound, improves productivity in the rubber compound preparation process and the vulcanization molding process of crosslinked molded products, such as seal members, and does not impair the low temperature properties of the crosslinked molded products. This rubber composition is effectively used as a crosslinking molding material for seal parts, for which a high pressure gas sealing function is particularly required in a low temperature environment, e.g., −39° C. or lower.

Claims

1. A rubber composition comprising 0.1 to 2.5 parts by weight of a lubricant having a flow temperature of 50 to 100° C. based on 100 parts by weight of an ethylene/butene/5-ethylidene-2-norbornene terpolymer.

2. The rubber composition according to claim 1, wherein a lubricant having a flow temperature of 60 to 95° C. is used.

3. The rubber composition according to claim 1, wherein the lubricant is a fatty acid-based lubricant.

4. The rubber composition according to claim 3, wherein the fatty acid-based lubricant is a fatty acid metal salt-based, fatty acid amide-based, or fatty acid ester-based lubricant.

5. The rubber composition according to claim 1, wherein the lubricant is an organosilicone-based lubricant.

6. The rubber composition according to claim 1, wherein 0.5 to 10 parts by weight of a organic peroxide is further compounded.

7. A crosslinked molded product obtained by crosslinking and molding the rubber composition according to claim 6.

8. The crosslinked molded product according to claim 7, which has a TR70 value specified in JIS K6261 corresponding to ISO 2921 of −39° C. or lower.

9. The rubber composition according to claim 2, wherein the lubricant is a fatty acid-based lubricant.

10. The rubber composition according to claim 2, wherein the lubricant is an organosilicone-based lubricant.

Description

EXAMPLES

[0038] The following describes the present disclosure with reference to Examples.

Example 1

[0039]

TABLE-US-00001 EBENB (Metallocene EBT, produced by 100 parts by weight Mitsui Chemicals, Inc.) HAF CB (Asahi #70, produced by 70 parts by weight Asahi Carbon Co., Ltd. DBF oil absorption amount: 101 ml/100 g) Zinc oxide 5 parts by weight Stearic acid 1 part by weight Fatty acid amide lubricant (Diamide O-200, 2 parts by weight produced by Nippon Kasei Chemical Company Limited; purified oleic acid amide; flow temperature: 73° C.) Plasticizer (Diana Process Oil PW-380, 5 parts by weight produced by Idemitsu Kosan Co., Ltd.); Antioxidant (Irganox 1010, 1 part by weight produced by BASF Japan) Organic peroxide (Percumyl D, produced by 3 parts by weight NOF Corporation; dicumyl peroxide,) Vulcanization accelerator (Taic, produced by 0.5 parts by weight Nippon Kasei Chemical Company Limited)

[0040] Among the above components that were aimed at a crosslinked product having a JIS A hardness of 75, the components other than an organic peroxide and a vulcanization accelerator were each kneaded with a kneader. Then, the organic peroxide and the vulcanization accelerator were added and kneaded with an open roll.

[0041] For the obtained open roll kneaded material, the stickiness of the surface of the unvulcanized rubber compound was measured using a tackiness checker (HTC-1, produced by Toyo Seiki Seisaku-sho, Ltd.). The results were evaluated as follows: 0 to less than 8 N: ◯, and 8 to 20 N: X.

[0042] Further, for the crosslinked product obtained by a primary crosslinking at 180° C. for 8 minutes and a secondary crosslinking at 180° C. for 24 hours, the TRIO value and the TR70 value were measured according to JIS K6261 at a recovery of 10% and 70% with respect to deformation in a low temperature region.

Example 2

[0043] In Example 1, the amount of the fatty acid amide lubricant was changed to 1 part by weight.

Example 3

[0044] In Example 1, the same amount (2 parts by weight) of a fatty acid ester-based lubricant (Struktol WB222, produced by Schill+Seilacher “Struktol” AG; flow temperature: 65° C.) was used in place of the fatty acid amide lubricant.

Example 4

[0045] In Example 1, the same amount (2 parts by weight) of an organosilicone-based lubricant (Struktol WS180, produced by Schill+Seilacher “Struktol” AG; flow temperature: 90° C.) was used in place of the fatty acid amide lubricant.

Comparative Example 1

[0046] In Example 1, the fatty acid amide lubricant was not used.

Comparative Example 2

[0047] In Example 1, the amount of the fatty acid amide lubricant was changed to 3 part by weight.

Comparative Example 3

[0048] In Example 1, the same amount (2 parts by weight) of a fatty acid derivative having a flow temperature 102° C. (Struktol WB16, produced by Schill+Seilacher “Struktol” AG) was used in place of the fatty acid amide lubricant.

Comparative Example 4

[0049] In Example 1, the same amount (2 parts by weight) of a fatty acid derivative having a flow temperature 105° C. (Struktol HT204, produced by Schill+Seilacher “Struktol” AG) was used in place of the fatty acid amide lubricant.

[0050] Following table shows the results obtained respectively in the above Examples and Comparative Examples.

TABLE-US-00002 TABLE Sticking between Unvulcanized TR10 TR70 Example rubber compound (° C.) (° C.) Example 1 ◯ −57 −40 Example 2 ◯ −57 −41 Example 3 ◯ −57 −39 Example 4 ◯ −57 −40 Comparative Example 1 X −57 −42 Comparative Example 2 ◯ −57 −37 Comparative Example 3 X −57 −40 Comparative Example 4 X −57 −40

[0051] The above results reveal that in Comparative Example 2, in which 3 parts by weight of a fatty acid amide lubricant was used, the evaluation of sticking between unvulcanized rubber compound is ◯, but the TR70 value increases by 5° C. as compared with Comparative Example 1, in which no fatty acid amide-based lubricant was added, thus indicating that there is a concern that the low temperature sealing properties may be affected.