JPH11100472A - Ethylene/propylene-based copolymer rubber composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject rubber composition capable of providing a vulcanized molding product not causing anchoring to the surface of copper, continuously and effectively usable, by mixing an ethylene/propylene copolymer rubber with an organic nitroso compound. SOLUTION: This rubber composition is obtained by mixing (A) an ethylene/ propylene copolymer rubber with (B) an organic nitroso compound (preferably a nitroso derivative of an aromatic amine such as N-nitrosodiphenylamine, methylphenylnitrosoamine, etc.). The blending ratio of the component B is preferably about 0.1-2.5 pts.wt. based on 100 pts.wt. of the component A. Consequently, copper damage preventing effects by the component B is obtained. Therefore the composition is preferably used as a molding material for a gasket or a packing to be brought into contact with copper.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an ethylene / propylene copolymer rubber composition. More specifically, the present invention relates to an ethylene / propylene-based copolymer rubber composition effectively used as a molding material for a gasket or a packing which comes into contact with copper.

[0002]

2. Description of the Related Art Ethylene-propylene copolymer rubber, which is ethylene-propylene copolymer rubber or ethylene-propylene-diene copolymer rubber, is used as a molding material for gaskets and packings, but is in contact with copper. In the case of being used, the adhesion to copper occurs and the deterioration is promoted, so that a phenomenon that the sealing performance is deteriorated is observed.

In order to avoid such a phenomenon, the following method has been proposed. (1) Method of adhering a protective substance between copper-ethylene-propylene copolymer rubber As a protective substance, a solid lubricant or a silicone coating agent is used. It is easier to flow out and it is difficult to continuously exert the effect of preventing sticking. (2) A method of blending a metal harm inhibitor and an antioxidant in rubber (Japanese Patent Application Laid-Open No. 54-127943). Aminobenzimidazolone acetylacetonate is used as an inhibitor of metal damage, especially copper damage, which acts as a chelating agent and collects copper ions that have penetrated rubber, but the chelating agent has expired. Alternatively, it is difficult to continuously exert the sticking prevention effect by flowing out.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a vulcanized molded product used in contact with copper.
An object of the present invention is to provide an ethylene / propylene copolymer rubber composition which does not cause sticking to a copper surface and which can be used continuously and effectively.

[0005]

SUMMARY OF THE INVENTION The object of the present invention is as follows.
This is achieved by an ethylene / propylene copolymer rubber composition in which an organic nitroso compound is blended with an ethylene / propylene copolymer rubber.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION As an organic nitroso compound, N-
The nitroso form of an aromatic amine such as nitrosodiphenylamine, methylphenylnitrosamine, or nitrosoaniline is used in an amount of about 100 parts by weight of ethylene-propylene copolymer rubber.
It is used in a proportion of 0.1 to 2.5 parts by weight, preferably about 0.1 to 2 parts by weight. If the compounding ratio of the organic nitroso compound is less than this, the expected effect of preventing copper damage is not obtained.On the other hand, if the compounding ratio is more than this, the normal physical properties of rubber, particularly the tensile strength is significantly reduced, so that it is preferable. Absent.

Ethylene containing an organic nitroso compound
A crosslinking agent and other necessary compounding agents are appropriately compounded in the propylene-based copolymer rubber composition, and preparation and vulcanization of the composition are performed in the same manner as in the conventional method.

[0008]

The vulcanized molded product obtained from the ethylene / propylene copolymer rubber composition according to the present invention has an organic nitroso compound which is not used even when it is used in contact with copper. It reacts and inactivates and does not cause sticking. In addition, since the organic nitroso compound added thereto is not easily removed, it is possible to continuously exert an anti-sticking effect. Therefore, this composition is effectively used as a molding material for gaskets and packings that come into contact with copper. be able to.

[0009]

Next, the present invention will be described with reference to examples.

Examples 1 to 3, Comparative Example 1 100 parts by weight of ethylene-propylene copolymer rubber (Esprene 501A manufactured by Sumitomo Chemical Co., Ltd.) SRF-HS carbon black 40 〃 zinc oxide 5 ス テ stearic acid 0.5, polymerization 2,2,4 -Trimethyl-1,2-dihydroquinoline 4 〃Dicumyl peroxide 4 〃N-nitrosodiphenylamine 0.1 〃 (Example 1) 0.3 〃 (Example 2) 2 〃 (Example 3) 3 〃 (Comparative example 1)

The above components are kneaded with an open roll, and the obtained composition is subjected to press vulcanization at 180 ° C. for 8 minutes and oven vulcanization (secondary vulcanization) at 150 ° C. for 15 hours to obtain a thickened composition. A 2 mm rubber sheet was vulcanized.

Comparative Example 2 In Example 1, N-nitrosodiphenylamine was not used.

Comparative Example 3 In Example 1, N-nitrosodiphenylamine was not used, and 2 parts by weight of mercaptobenzothiazole was further used.

The following items were measured for the vulcanized rubber sheets obtained in the above Examples and Comparative Examples. Normal property: JIS K-6301 compliant Anti-sticking property: A 2 x 5 mm test piece was cut out from a vulcanized rubber sheet, and 6 to 8 test pieces were polished on a pure copper plate (80 x 100 (× 0.8mm) sandwiched between two pieces so that the cut surface of the test piece was in contact with the copper plate surface, put it in a 40% compressed state in a 130 ° C. gear oven for 100 hours, then released from compression and allowed to cool Thereafter, the test piece is peeled from the copper plate. When peeled, the rubber was broken, and was marked X when the rubber remained on the copper plate, and was marked when it was not broken. Copper plate contact surface alteration: produces copper (I) sulfide and copper (II) oxide

The measurement results are shown in the following table. Table Example Comparative Example Measurement items 1 2 3 1 2 3 [Normal physical properties] Hardness (JIS A) 64 64 60 57 64 61 Tensile strength (MPa) 19.0 18.4 14.2 10.3 19.2 15.7 Elongation (%) 410 350 710 910 430 850 [Anti-sticking property] ○ ○ ○ ○ × × [Deterioration of copper plate contact surface] Yes Yes Yes Yes No Yes

Claims (2)

[Claims] 1. An ethylene / propylene copolymer rubber composition comprising an ethylene / propylene copolymer rubber and an organic nitroso compound. 2. The ethylene / propylene copolymer rubber composition according to claim 1, which is used as a molding material for a gasket or a packing in contact with copper.