THERMOELASTIC BLEND COMPOSITIONS

摘要

The present invention is at least a two-component thermoplastic elastomeric blend composition comprising at least one styrenic block copolymer wherein t he composition has essentially the same comparative elasticity, high temperatur e serviceability and hardness as the unmodified, undiluted (neat) block copolymer portion of the composition. The composition also shows enhanced thermal stability and processibility and is well suited for fabricating elastic moldings, films and fibers as well as for formulating with asphalts, adhesives and sealants. The novel thermoplastic elastomeric blend compositio n comprises (a) from 50 to 99 percent by weight of at least one styrenic block copolymer and (b) 1 to 50 percent by weight of at least one homogeneously branched ethylene interpolymer having a density from 0.855 g/cc to 0.905 g/c c, wherein the ethylene interpolymer in the amount employed is a substantially inert extender of the styrenic block copolymer and the composition is characterized as having: (i) storage moduli throughout the range of -26 ~C t o 24 ~C of less than 3.5 x 109 dynes/cm2, (ii) a ratio of storage modulus at - 26 ~C to storage modulus at 24 ~C of less than 4, and (iii) storage moduli at - 26 ~C and 24 ~C 0.2 to 3 times higher than the storage moduli at -26 ~C and 24 ~C, respectively,of the neat block copolymer portion of the composition.