Heat-resistant rubber composition

Abstract

A heat-resistant rubber composition of the invention is a vulcanizable composition comprising a specific ethylene-α-olefin-nonconjugated polyene copolymer rubber (A) and an organic peroxide (B). This heat-resistant composition has high crosslinking efficiency given by the organic peroxide and high modulus, and can provide a vulcanized rubber molded product of excellent resistance to environmental deterioration such as thermal aging resistance. The other heat-resistant rubber composition of the invention is a vulcanizable composition comprising 100 parts by weight of a specific ethylene-α-olefin-nonconjugated polyene copolymer rubber (A) composed of ethylene, an α-olefin or 3 to 20 carbon atoms and a nonconjugated polyene which is a vinyl end group-containing norbornene compound, 0.2 to 5 parts by weight of an amine type anti-aging agent (C) and/or a hindered phenol type anti-aging agent (D), 1 to 10 parts by weight of a sulfur type anti-aging agent (E) and an organic peroxide (B). This heat-resistant rubber composition can provide a vulcanized rubber molded product showing not only excellent mechanical properties and electrical properties and but also prominently high thermal aging resistance.

What is claimed is:  
     
       1. A heat-resistant rubber composition comprising: 
       an ethylene-α-olefin-nonconjugated polyene copolymer rubber (A) composed of ethylene, an α-olefin of 3 to 20 carbon atoms and a nonconjugated polyene, and  
       an organic peroxide (B); and having vulcanizable properties,  
       said ethylene-α-olefin-nonconjugated polyene copolymer rubber (A) having the following properties:  
       (1) a molar ratio of ethylene to the α-olefin of 3 to 20 carbon atoms is in the range of 40/60  55/45 to 95/5  85/15 (ethylene/α-olefin),  
       (2) the nonconjugated polyene is 5-vinyl-2-norbornene, 5-isopropenyl-2-norbornene or 5-isobutenyl-2-norbornene,  
       (3) the nonconjugated polyene content is in the range of 0.5 to 50 g/100 g in terms of iodine value, and  
       (4) an intrinsic viscosity (η), as measured in decahydronaphthalene at 135° C., of 0.1 to 10 dl/g.  
     
     
       2. A heat-resistant rubber composition comprising: 
       (I) an ethylene-e-olefin-nonconjugated polyene copolymer rubber (A) composed of ethylene, an α-olefin of 3 to 20 carbon atoms and a nonconjugated polyene, in an amount of 100 parts by weight,  
       (II) an amine type anti-aging agent (C) composed of diphenylamines and/or phenylenediamines, in an amount of 0.2 to 5 parts by weight, and/or a hindered phenol type anti-aging agent (D) in an amount of 0.2 to 5 parts by weight, and  
       (III) a sulfur type anti-aging agent (E) in an amount of 1 to 10 parts by weight; and  
       having vulcanizable properties,  
       said ethylene-α-olefin-nonconjugated polyene copolymer rubber (A) having the following properties:  
       (1) a molar ratio of ethylene to the α-olefin of 3 to 20 carbon atoms is in the range of 40/60 to 95/5 (ethylene/α-olefin),  
       (2) the nonconjugated polyene is 5-vinyl-2-norbornene, 5-isopropenyl-2-norbornene or 5-isobutenyl-2-norbornene,  
       (3) the nonconjugated polyene content is in the range of 0.5 to 50 g/100 g in terms of an iodine value, and  
       (4) an intrinsic viscosity (η), as measured in decalin at 135° C., of 0.1 to 10 dl/g.  
     
     
       3. The heat-resistant rubber composition as claimed in  claim 2  wherein the ethylene-.alpha.-olefin-nonconjugated polyene copolymer rubber (A) is a blend of: 
       (I) an ethylene-α-olefin-nonconjugated polyene copolymer rubber (A1) having an intrinsic viscosity (η), as measured in decalin at 135° C., of 1 to 10 dl/g, in an amount of 30 to 95 parts by weight, and  
       (II) an ethylene-α-olefin-nonconjugated polyene copolymer rubber (A2) having an intrinsic viscosity (η), as measured in decalin at 135° C., of 0.1 to 5 dl/g, this intrinsic viscosity being different from the intrinsic viscosity of the ethylene-α-olefin-nonconjugated polyene copolymer rubber (A1), in an amount of 5 to 70 parts by weight,  
       the total amount of said components (A1) and (A2) being 100 parts by weight; and  
       said ethylene-α-olefin-nonconjugated polyene copolymer rubber (A1) having the following properties:  
       (1) said copolymer rubber is a copolymer rubber composed of ethylene, an α-olefin of 3 to 20 carbon atoms and a nonconjugated polyene,  
       (2) a molar ratio of ethylene to the α-olefin of 3 to 20 carbon atoms is in the range of 40/60 to 95/5 (ethylene/α-olefin),  
       (3) the nonconjugated polyene is 5-vinyl-2-norbornene, and  
       (4) the nonconjugated polyene content is in the range of 0.5 to 50 g/100 g in terms of an iodine value; and  
       said ethylene-α-olefin-nonconjugated polyene copolymer rubber (A2) having the following properties:  
       (1) said copolymer rubber is a copolymer rubber composed of ethylene, an α-olefin of 3 to 20 carbon atoms and a nonconjugated polyene,  
       (2) a molar ratio of ethylene to the α-olefin of 3 to 20 carbon atoms is in the range of 40/60 to 95/5 (ethylene/α-olefin),  
       (3) the nonconjugated polyene is 5-vinyl-2-norbornene, 5-isopropenyl-2-norbornene or 5-isobutenyl-2-norbornene, and  
       (4) the nonconjugated polyene content is in the range of 0.5 to 50 g/100 g in terms of an iodine value.  
     
     
       4. The heat-resistant rubber composition as claimed in  claim 3 , wherein the ethylene-α-olefin-nonconjugated polyene copolymer rubber (A) which is a blend of the ethylene-α-olefin-nonconjugated polyene copolymer rubber (A1) and the ethylene-α-olefin-nonconjugated polyene copolymer rubber (A2) has: 
       (i) a Mooney viscosity (ML 1+4 (100° C.)) of 5 to 180,  
       (ii) a molar ratio of ethylene to the α-olefin of 40/60 to 95/5 (ethylene/α-olefin), and  
       (iii) a nonconjugated polyene content of 0.5 to 50 g/100 g in terms of an iodine value.  
     
     
       5. The heat-resistant rubber composition as claimed in  claim 3  or  claim 4 , wherein the ethylene-α-olefin-nonconjugated polyene copolymer rubber (A1) and/or the ethylene-α-olefin-nonconjugated polyene copolymer rubber (A2) is an ethylene-α-olefin-nonconjugated polyene copolymer rubber having been graft-modified with an unsaturated carboxylic acid or its derivative. 
     
     
       6. The heat- resistant rubber composition according to    claim 1   , wherein the α - olefin is propylene.    
     
     
       7. The heat- resistant rubber composition according to    claim 2   , wherein the α - olefin is propylene.    
     
     
       8. The heat- resistant rubber composition according to    claim 7   , wherein the molar ratio of ethylene to propylene is in the range of  55 / 45  to  85 / 15 .    
     
     
       9. The heat- resistant rubber composition according to    claim 3   , wherein the α - olefin in at least one of copolymer rubber  ( A 1   )  and copolymer rubber  ( A 2   )  is propylene.    
     
     
       10. The heat- resistant rubber composition according to    claim 3   , wherein the α - olefin in each of copolymer rubber  ( A 1   )  and copolymer rubber  ( A 2   )  is propylene.    
     
     
       11. The heat- resistant rubber composition according to    claim 3   , wherein in at least one of copolymer rubber  ( A 1   )  and copolymer rubber  ( A 2   ) , the molar ratio of ethylene to the α - olefin of from  3  to  20  carbon atoms is in the range of from  55 / 45  to  85 / 15 .    
     
     
       12. The heat- resistant rubber composition according to    claim 3   , wherein in each of copolymer rubbers  ( A 1   )  and  ( A 2   )  the molar ratio of ethylene to the α - olefin of  3  to  20  carbon atoms is from  55 / 45  to  85 / 15 .    
     
     
       13. The heat- resistant rubber composition according to    claim 12   , wherein the α - olefin of  3  to  20  carbon atoms is propylene.    
     
     
       14. A vulcanized composition obtained by vulcanizing the heat- resistant rubber composition according to any one of    claims 1    to    3    or    6    to  13 .    
     
     
       15. A molded or foamed article obtained by molding or foaming the heat- resistant rubber composition according to any one of    claim 1    to  3  or  6  to  13 .    
     
     
       16. An automotive part comprising a heat- resistant rubber composition according to any one of claims  1 ,  2  or  3 .    
     
     
       17. An automotive part according to  claim 16 , wherein the heat- resistant rubber composition is vulcanized.    
     
     
       18. An automotive part according to  claim 16 , wherein the heat- resistant rubber composition is molded or foamed.    
     
     
       19. An automotive part according to  claim 16 , which is a door glass run channel, and wherein the heat- resistant rubber composition maybe vulcanized, molded or foamed.    
     
     
       20. An automotive part according to  claim 16 , which is a window frame, and wherein the heat- resistant rubber composition may be vulcanized, molded or foamed.    
     
     
       21. An automotive part according to  claim 16 , which is a radiator hose, and wherein the heat- resistant rubber composition may be vulcanized, molded or foamed.    
     
     
       22. An automotive part according to  claim 16 , which is a brake part, and wherein the heat- resistant rubber composition may be vulcanized, molded or foamed.    
     
     
       23. An automotive part according to  claim 16 , which is a wiper blade, and wherein the heat- resistant rubber composition may be vulcanized, molded or foamed.    
     
     
       24. An industrial rubber part comprising a heat- resistant rubber composition according to any one of claims  1 ,  2  or  3 .    
     
     
       25. An industrial rubber part according to  claim 24 , wherein the heat- resistant rubber composition is vulcanized.    
     
     
       26. An industrial rubber part according to  claim 24 , wherein the heat- resistant rubber composition is molded or foamed.    
     
     
       27. An industrial rubber part according to  claim 24 , which is a rubber roll, and wherein the heat- resistant rubber composition may be vulcanized, molded or foamed.    
     
     
       28. An industrial rubber part according to  claim 24 , which is a rubber belt, and wherein the heat- resistant rubber composition may be vulcanized, molded or foamed.    
     
     
       29. An industrial rubber part according to  claim 24 , which is a rubber packing, and wherein the heat- resistant rubber composition may be vulcanized, molded or foamed.    
     
     
       30. An industrial rubber part according to  claim 24 , which is a rubber hose, and wherein the heat- resistant rubber composition may be vulcanized, molded or foamed.    
     
     
       31. An electrically insulating anode cap comprising the heat- resistant rubber composition of any one of claims  1 ,  2  or  3 , and wherein said heat - resistant rubber composition may be vulcanized, molded or foamed.    
     
     
       32. An electrically insulating rubber grommet, comprising the heat- resistant rubber composition according to any one of claims  1 ,  2  or  3 , and wherein said heat - resistant rubber composition may be vulcanized, molded or foamed.    
     
     
       33. A gasket for building materials comprising the heat- resistant rubber composition according to any one of claims  1 ,  2  or  3 , and wherein the heat - resistant rubber composition may be vulcanized, molded or foamed.