| 摘要 |
A gel or gelloid liquid-extended polymer composition having (i) an ASTM D217 cone penetration value within the range from 100 to 400 (10<-1> millimetres), (ii) an ASTM D412 ultimate elongation greater than 100 % with substantially elastic deformation to an elongation of at least 100 %, (iii) an ASTM D412 ultimate tensile strength of less than 1 MegaPascal, and (iv) a dynamic storage modulus at 23<o>C of less than 50000 Pascals; the composition comprising an intimate mixture of a) mainly a block copolymer containing relatively hard blocks and relatively elastomeric blocks; b) additional polymer or copolymer material having at least partial compatibility with, and a higher glass transition, softening or melting temperature than, the hard blocks of the said block copolymer; and c) at least 500 parts by weight of extender liquid per 100 parts by weight of the said block copolymer, which liquid extends and softens the elastomeric blocks of the said block copolymer. SEBS triblock copolymers with polyphenylene ether "alloys" as the added material are preferred, the extender liquid preferably being an oil of substantially zero aromatic content. |
