Block copolymer composition for overmolding any nylon

A thermoplastic elastomer (“TPE”) composition for overmolding a predominantly nylon substrate consisting essentially of,

• an essentially polyamide-free blend of,
• (a) an inert filler present in an amount in the range from 5 to 40% by weight of the composition,
• (b) a plasticizer, unreactive with an ingredient in the composition, present in a minor amount by weight relative to the composition;
• (c) a block copolymer selected from the group consisting of
• (C1), a polystyrene-polydiene-polystyrene block copolymer (SDS rubber), or an at least partially hydrogenated polystyrene-polydiene-polystyrene block copolymer (SHDS rubber), the SDS and SHDS each having polystyrene endblocks, one at each end of a polydiene midblock, which midblock includes a polymerized vinyl aromatic monomer, the polystyrene endblocks being together present in an amount in the range from about 20% to 30% by weight of the block copolymer, not including the polystyrene in the polydiene midblock, so that (C1) has a weight average molecular weight (“Mw”) high enough to be thermally stable at 282° C. (540° F.),
• (C2), a functionalized at least partially hydrogenated “high rubber” SHDS having a functionality of essentially 1%, the “small end blocks” together present in an amount in the range from about 8-25% by weight (that is, each endblock has a much lower molecular weight than the rubbery midblock), and
• (C3), a functionalized at least partially hydrogenated SHDS having a functionality of >1% but <2%, in which the end blocks are together present in an amount in the range from >25%-35% by weight;
• in any combination, provided that only (C2) may be present without (C1) and (C3);
• (d) from 0-30% by weight of the composition, of a functionalized polyolefin (FP), the olefin having from 2 to 8 carbon atoms;
• (e) from 0-15% by wt of the composition, of a hydrogenated nonfunctionalized hydrogenated polystyrene-polydiene-polystyrene (SHDS) block copolymer;
• and,
• (f) an additive to enhance the useful life of the composition.