Composition and method of improving the unvulcanized properties of blends containing reclaimed rubber

A prevulcanization process for producing a reclaimed rubber blend, comprising:

• improving the green strength of a reclaimed rubber-elastomer blend by
• obtaining from about 5 parts by weight to about 100 parts by weight of reclaimed rubber, said reclaimed rubber produced by devulcanizing scrap rubber with microwave energy, said reclaimed rubber selected from the group consisting of polychloroprene, chlorobutyl rubber, bromobutyl rubber, butyl rubber, nitrile rubber, nitrile rubber-poly(vinyl chloride) blends having up to 30 percent by weight by poly(vinyl chloride), EPDM, natural or synthetic cis-1,4-polyisoprene, polyalkenylenes, elastomers made from monomers selected from the group consisting of conjugated dienes having from 4 to 10 carbon atoms, interpolymers of said dienes (1) among themselves, or (2) with monomers selected from the group consisting of vinyl substituted hydrocarbon compounds having from 8 to 12 carbon atoms, and combinations thereof;
• adding to said reclaimed rubber from about 95 parts by weight to about 0 parts by weight of an elastomer, said elastomer selected from the group consisting of natural or synthetic cis-1,4-polyisoprene, polyalkenylenes, elastomers made from monomers selected from the group consisting of conjugated dienes having from 4 to 10 carbon atoms, interpolymers of said dienes (1) among themselves, or (2) with monomers selected from the group consisting of vinyl substituted hydrocarbon compounds having from 8 to 12 carbon atoms;
• and combinations thereof, the total amount of said reclaimed rubber and said elastomer being 100 parts by weight;
• adding to said reclaimed rubber and said elastomer a semi-crystalline butene polymer having a number average molecular weight of from about 30,000 to about 500,000, the amount of said butene polymer ranging from about 2 parts by weight to about 30 parts by weight per 100 parts by weight of said elastomer-reclaimed rubber mixture, said butene polymer selected from the group consisting of polybutene and interpolymers made from 1-butene monomer and at least one monomer selected from the group consisting of (a) alpha-olefins having 2 through 16 carbon atoms, (b) non-conjugated dienes having the formula:
• ##STR10## where R.sub.1, R.sub.2 and R.sub.3 is a hydrogen, a lower alkyl group containing from 1 to 4 carbon atoms, or an aryl group;
• where R.sub.4 is an aryl group or a lower alkyl group containing from 1 to 9 carbon atoms, and n is an integer having a value of from 1 to 6, and wherein the said R.sub.1 's in the ##STR11## group may be similar or dissimilar, (c) non-conjugated alpha-, omega-polyenes having from 6 to 36 carbon atoms which may or may not contain internal unsaturation, and (d) combinations thereof, said butene in said interpolymers comprises from 99.9 to 65 mole percent of the total monomers;
• and
• mixing said elastomer, said reclaimed rubber and said butene polymer to produce an elastomer-reclaimed rubber blend having improved green strength before vulcanization.