Sulfur vulcanizable rubber compound
AssigneeThe Goodyear Tire & Rubber Company
InventorsNeil Arthur Maly, John Robert McGilvrey
Life of this patent
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Abstract
This invention relates to the discovery that the combination of tetrabenzylthiuram disulfide, cashew nut oil modified novolak-type phenolic resin, a bismaleimide compound and a sulfenamide compound provides for excellent vulcanization of rubbers and results in desirable final rubber vulcanizate physical properties in the absence of generating undesirable nitrosamines and fumes during processing and cure.
Claims16
A sulfur vulcanizable rubber compound comprising:
- (a) a rubber selected from the group consisting of natural rubber, a rubber derived from a diene monomer and mixtures thereof,
- b) from about 0.10 to about 0.75 phr of a disulfide accelerator consisting of tetrabenzylthiuram disulfide;
- (c) from about 1 to about 12 phr of a modified phenolic resin consisting of a cashew nut oil modified novolak-type phenolic resin;
- (d) from about 0.5 to about 3 phr of a bismaleimide compound of the general formula:
- ##STR9## wherein R is a divalent acyclic aliphatic group having from about 2 to 16 carbon atoms, cyclic aliphatic group having from about 5 to 20 carbon atoms, aromatic group having from about 6 to 18 carbon atoms, or alkylaromatic group having from about 7 to 24 carbon atoms, wherein these divalent groups may contain a hereto atom selected from O, N and S;
- X is O or an integer of from 1 to 3 and Y is hydrogen or --CH.sub.3
- (e) from about 0.5 phr to about 3 phr of a sulfenamide compound of the general formula:
- ##STR10## wherein R.sup.1 is hydrogen, an acyclic aliphatic group having from about 1 to 10 carbon atoms, or a cyclic aliphatic group having from about 5 to 10 carbon atoms;
- and R.sup.2 is hydrogen, a cyclic aliphatic group having from about 5 to 10 carbon atoms or a mercaptobenzothiazolyl group of the formula:
- ##STR11## and (f) from about 0.5 to about 6 phr of sulfur, a sulfur donor and mixtures thereof.
A process for the vulcanization of a rubber compound comprising heating to a temperature ranging from 125.degree. C. to 180.degree. C. a rubber compound comprising:
- (a) a rubber selected from the group consisting of natural rubber, a rubber derived from a diene monomer and mixtures thereof,
- (b) from about 0.10 to about 0.75 phr of a disulfide accelerator consisting of tetrabenzylthiuram disulfide;
- (c) from about 1 to about 12 phr of a modified phenolic resin consisting of a cashew nut oil modified novolak-type phenolic resin;
- (d) from about 0.5 to about 3 phr of a bismaleimide compound of the general formula:
- ##STR12## wherein R is a divalent acyclic aliphatic group having from about 2 to 16 carbon atoms, cyclic aliphatic group having from about 5 to 20 carbon atoms, aromatic group having from about 6 to 18 carbon atoms, or alkylaromatic group having from about 7 to 24 carbon atoms, wherein these divalent groups may contain a hetero atom selected from O, N and S;
- X is O or an integer of from 1 to 3 and Y is hydrogen or --CH.sub.3 ;
- (e) from about 0.5 phr to about 3 phr of a sulfenamide compound of the general formula:
- ##STR13## wherein R.sup.1 is hydrogen, an acyclic aliphatic group having from about 1 to 10 carbon atoms, or a cyclic aliphatic group having from about 5 to 10 carbon atoms;
- and R.sup.2 is hydrogen, a cyclic aliphatic group having from about 5 to 10 carbon atoms or a mercaptobenzothiazolyl group of the formula:
- ##STR14## and (f) from about 0.5 to about 6 phr of sulfur, a sulfur donor and mixtures thereof.
Dependencies are inferred from the claim text.