| 摘要 |
PURPOSE: To impart an excellent impermeability against a chlorinated phenol and a chlorinated anisole to a gasket by forming the gasket of a thermoplastic blend which is a homogeneous blend of a specified ratio of butyl rubber blend and thermoplastic polymer mixture. CONSTITUTION: This gasket is formed of a thermoplastic blend of a homogeneous blend of 20-60 wt.% of butyl rubber and 40-80 wt.% of other thermoplastic polymers. Other thermoplastic polymers in the blend are homogeneously mixed with butyl rubber and extruded to a cap to form a homogeneous melt to obtain an adhesive gasket having required properties. Preferable thermoplastic materials are polyethylene, copolymer of polyethylene and butylene, polypropylene, and thermoplastic rubber, and the like. Thermoplastic blends are formed of respective polymer pellets and the melt is inserted into crown caps of a number of bottles to be formed into an annular gasket. |
