Sidewall features for tires
View Patent ↗A tire having a decorative side wall feature, the decorative side wall feature being based upon a rubber composition, the rubber composition comprising between 15 and 25 parts by weight per 100 parts by weight of rubber (phr) of a highly unsaturated diene elastomer, between 60 and 80 phr of a butyl rubber and between 5 and 15 phr of an EPDM elastomer characterized as having an ethylene content of between 65 wt. % and 75 wt. % as measured by ASTM D 3900-95, not including diene, and a Mooney viscosity ML(I+4) at 125° C. of between 60 and 80. The light-colored rubber composition may further include between 5 and 25 phr of a paraffinic processing oil and a non-black filler.
1. A tire comprising a sidewall surface feature, the sidewall surface feature being based upon a rubber composition, the rubber composition comprising:
between 15 and 25 parts by weight per 100 parts by weight of rubber (phr) of a highly unsaturated diene elastomer, wherein the highly unsaturated diene elastomer is an elastomer comprising a content of units of diene origin greater than 50 mol. %;
between 60 and 80 phr of a butyl rubber;
between 5 and 15 phr of an EPDM elastomer characterized as having an ethylene content of between 65 wt. % and 75 wt. % as measured by ASTM D 3900-95, not including diene, and a Mooney viscosity ML(1+4) at 125° C. of between 60 and 80;
between 5 and 25 phr of a paraffinic processing oil; and
a non-black filler.
2. The tire of claim 1 , wherein the highly unsaturated diene elastomer is natural rubber.
3. The tire of claim 1 , wherein the highly unsaturated diene elastomer is selected from natural rubber, synthetic polyisoprene rubber or combinations thereof.
4. The tire of claim 1 , wherein the highly unsaturated diene elastomer is limited in quantity to between 15 and 21 phr.
5. The tire of claim 4 , wherein the highly unsaturated diene elastomer is natural rubber.
6. The tire of claim 1 , wherein the butyl rubber is a halogenated butyl rubber.
7. The tire of claim 6 , wherein the butyl rubber is a chlorobutyl rubber.
8. The tire of claim 1 , wherein the butyl rubber is characterized as having a Mooney viscosity ML (1+8) at 125° C. of between 45 and 55.
9. The tire of claim 1 , wherein the EPDM is characterized as having an ethylidene norbornene content of 0.9 and 6 wt. % as measured by ASTM D 6047.
10. The tire of claim 1 , wherein the rubber composition does not include a staining antidegradant compound.
11. The tire of claim 1 , wherein the paraffinic processing oil is characterized as having a dynamic glass transition temperature of less than −75° C.
12. The tire of claim 1 , wherein the non-black filler is selected from bright clay, silica, talc, carbonates or combinations thereof.
13. The tire of claim 12 , wherein the non-black filler is between 25 and 100 phr of high bright clay.
14. The tire of claim 12 , wherein the non-black filler is between 25 and 100 phr of talc.
15. The tire of claim 1 , wherein the rubber composition further comprises:
titanium dioxide.
16. The tire of claim 1 , wherein the paraffinic oil is between 10 phr and 20 phr.
17. The tire of claim 1 , wherein the sidewall surface feature is selected from a raised lettering on the sidewall, a stripe around the sidewall or combinations thereof.