Extrusion of a foamable melt consisting of mixed polyolefin and rubber copolymer

摘要

A tapered stepped land having a choked funnel section which terminates in a lateral longitudinal section results in the formation of a foamed extrudate of a vulcanized blend of polyolefin and rubber which is a mass of closed cells having a specific gravity in the range from about 0.1 to 0.5 and the cells are sheathed in a dense non-porous, smoothly continuous skin which is formed integrally with the extrudate. The dense skin makes it possible to deposit a thin slip-coating of a low friction material longitudinally upon a chosen portion of the surface. An extruded weatherseal for the glass of an automobile's window has the slip-coating deposited as a thin film on a contacting strip of a surface which is in contact with the glass.