摘要:
Thermoplastic elastomeric compositions and processes for preparing the compositions comprising a blend of polypropylene, styrene-ethylene butylene-styrene copolymer, ethylene-propylene-diene monomer elastomer, linear low density polyethylene, peroxide crosslinking agent and a crosslinking coagent. The peroxide crosslinking agent and crosslinking coagent provide a crosslinking system. The compositions improve melt strength and increase resistance to flow and tear. The composition may further comprise mineral oil, antioxidant, colorant, a processing aid and stabilizer and mixtures thereof. The processes for preparing thermoplastic elastomeric compositions are particularly useful in microcellular injection molding to form articles with improved surface characteristics.
摘要:
Described are a thermoplastic polymer composition comprising (A) a block copolymer formed of a polymer block composed mainly of an aromatic vinyl compound and another polymer block composed mainly of isobutylene; and (B) a crosslinked rubber of at least one rubber selected from natural rubber, diene polymer rubber, olefin polymer rubber, acrylic rubber and fluorine rubber at a weight ratio of 90:10 to 10:90; and molded or formed products and hermetically sealing materials produced using the composition. The above thermoplastic polymer composition is excellent in moldability or formability, gas barrier properties, compression set resistance, hermetically sealing properties, sealing properties, flexibility, mechanical properties, oil resistance, safety, hygienic properties and the like. By melt molding or forming of the composition under heat, general-purpose molded or formed products, hermetically sealing materials such as sealant, packing material or gasket, particularly, stopper or gasket for syringe for the medical use can be produced smoothly.