Rubber composition and vibration damper using the rubber composition
View Patent ↗A torsional vibration damper or other vibration damping device with a rubber vibration absorbing element. The rubber element is a peroxide-cured composition based on 100 parts of ethylene-alpha-olefin elastomer, and 5 to 100 parts of polyvinyl butyral polymer which may have a molecular weight from about 40,000 to about 250,000. The composition may also include a compatibilizer or homogenizer, such as chlorinated polyethylene. The polyvinyl butyral increases the damping of the composition, and the compatibilizer improves the temperature stability of the damping.
1. A vibration absorbing device comprising a rubber vibration absorbing element comprising a vulcanized rubber composition comprising: ethylene-alpha-olefin elastomer and polyvinyl butyral and chlorinated polyethylene as a compatibilizer; wherein said composition comprises 100 parts by weight of said elastomer, from 1 to 50 parts of said chlorinated polyethylene, and from 5 to 100 parts of said polyvinyl butyral.
2. The device of claim 1 wherein said composition comprises 100 parts by weight of said elastomer and from 5 to 30 parts of said polyvinyl butyral.
3. The device of claim 1 wherein said composition comprises 100 parts by weight of said elastomer, from 1 to 20 parts of said chlorinated polyethylene, and from 5 to 30 parts of said polyvinyl butyral.
4. The device of claim 1 wherein said polyvinyl butyral is present in said composition in an amount effective to increase tan δ of said element by at least 30% at a temperature in the range of from 50 to 100° C. and at a suitable frequency, relative to a similar element without polyvinyl butyral.
5. The device of claim 1 wherein said compatibilizer is present in said composition in an amount effective to broaden the temperature dependence of tan δ of said element over a temperature range of from 50 to 100° C. and at a suitable frequency, relative to a similar element without said compatibilizer.
6. The device of claim 1 further comprising a rubber-to-metal adhesion promoter.
7. The device of claim 6 wherein said promoter is one or more selected from the group consisting of metal salts of unsaturated organic acids and maleated polybutadiene resins.
8. The device of claim 1 wherein said device is selected from the group consisting of a torsional vibration damper, a vibration isolator, a belt, a hose, and a rubber element of one of the foregoing.
9. The device of claim 1 wherein said rubber element is cured by a free-radical-producing means.
10. The device of claim 9 wherein said free-radical-producing means is selected from the group consisting of organic peroxides and ionizing radiation.
11. The device of claim 1 wherein said elastomer is selected from the group consisting of ethylene-propylene copolymers, ethylene-propylene-diene terpolymers, ethylene-octene copolymers, ethylene-octene-diene terpolymers, ethylene-butene copolymers, ethylene-butene-diene terpolymers, and blends thereof.
12. The device of claim 1 wherein said polyvinyl butyral has a weight average molecular weight in the range from about 40,000 to about 250,000.
13. A rubber composition comprising: 100 parts of ethylene-alpha-olefin elastomer; 5 to 100 parts of polyvinyl butyral; and 1 to 50 parts of chlorinated polyethylene.
14. The composition of claim 13 wherein said polyvinyl butyral has a weight average molecular weight in the range from about 40,000 to about 250,000.
15. The composition of claim 14 further comprising a rubber-to-metal adhesion promoter, wherein said composition is peroxide cured.
16. The composition of claim 15 wherein said promoter is one or more selected from the group consisting of metal salts of unsaturated organic acids and maleated polybutadiene resins.
17. The composition of claim 15 wherein said elastomer is selected from the group consisting of ethylene-propylene copolymers, ethylene-propylene-diene terpolymers, ethylene-octene copolymers, ethylene-octene-diene terpolymers, ethylene-butene copolymers, ethylene-butene-diene terpolymers, and blends thereof.
18. The composition of claim 13 comprising from 5 to 30 parts of said polyvinyl butyral and from 1 to 20 parts of said chlorinated polyethylene.
19. The composition of claim 13 wherein said polyvinyl butyral is present in an amount effective to increase tan δ of said element by at least 30% at a temperature in the range of from 50 to 100° C. and at a suitable frequency, relative to a similar element without polyvinyl butyral.
20. The composition of claim 13 wherein said chlorinated polyethylene is present in an amount effective to broaden the temperature dependence of tan δ of said element over a temperature range of from 50 to 100° C. and at a suitable frequency, relative to a similar element without said chlorinated polyethylene.