Elastomer formulation using a combination of polymers to create ozone resistance without addition of wax
A shaped article is formed from a cured rubber composition comprising EPDM and a diene rubber. The shaped article exhibits a coefficient of friction greater than 0.1.
1. A shaped article formed from a cured rubber composition comprising:
ethylene propylene diene monomer (EPDM) having an organic polymer comprising sulfur covalently incorporated therein;
a diene rubber; and
a curing agent that cures the EPDM having the organic polymer comprising sulfur covalently incorporated therein to the diene rubber,
wherein the article has a coefficient of friction greater than 0.1, and
wherein the EPDM having the organic polymer comprising sulfur covalently incorporated therein is present in the cured rubber composition at a concentration of greater than about 5 wt. % and less than about 25 wt. % based on the total weight of the EPDM and the diene rubber.
2. The shaped article according to claim 1 , wherein the article has a coefficient of friction greater than 0.2.
3. The shaped article according to claim 1 , wherein the article has a coefficient of friction greater than 0.5.
4. The shaped article according to claim 1 , wherein the article has a coefficient of friction from 0.5 to 0.8.
5. The shaped article according to claim 4 , giving a pass on an ozone resistance test according to ASTM D-1149 when subjected to 50 pphm ozone for 72 hours at 40° C.
6. The shaped article according to claim 1 , wherein the article has a coefficient of friction from 0.6 to 0.7.
7. The shaped article according to claim 1 , giving a pass on an ozone resistance test according to ASTM D-1149 when subjected to 200 pphm ozone for 24 hours at 40° C.
8. The shaped article according to claim 1 , wherein the article comprises 25 wt. % EPDM and 75 wt. % diene rubber based on the total weight on the EPDM having the organic polymer comprising sulfur covalently incorporated therein and the diene rubber.
9. The shaped article according to claim 1 , wherein the organic polymer comprising sulfur includes a poly(alkyl phenol) disulfide polymer.
10. The shaped article according to claim 1 , wherein the cured rubber composition does not include a wax.
11. A shaped article formed from a cured rubber composition comprising:
a diene; and
an ethylene propylene diene monomer (EPDM) having an organic polymer comprising sulfur covalently incorporated therein,
wherein the diene is cross-linked to the EPDM having the organic polymer comprising sulfur with elemental sulfur.
12. The shaped article according to claim 11 , wherein the EPDM having the organic polymer comprising sulfur covalently incorporated therein is present in the cured rubber composition at a concentration of greater than about 5 wt. % and less than about 25 wt. %.
13. The shaped article according to claim 11 , wherein the organic polymer comprising sulfur includes a poly(alkyl phenol) disulfide polymer.
14. The shaped article according to claim 13 , wherein the shaped article has a coefficient of friction greater than 0.2 and passes an ozone resistance test according to ASTM D-1149 when subjected to 200 pphm ozone for 24 hours at 40° C.