FORMSTYCKE AV EN SAMMANSAETTNING INNEHAOLLANDE SYNTETISK HAERDPLASTHARTS OCH ETT POROEST MATERIAL OCH FOERFARANDE FOER FRAMSTAELLNING DAERAV.

摘要

A rail pad or other shaped article in the form of a resiliently compressible extrudate having a textured surface and comprising particles or granules of cork or similar resiliently compressible cellular material substantially homogenously dispersed throughout a polymeric matrix of generally saturated thermoplastic synthetic resin, preferably ethylene/vinyl acetate copolymer, which has a stiffness modulus of not more than 1000 MPa and is extrudable under conditions at which the cellular material is not significantly degraded, the extrudate having a Poissons ratio less than that of the matrix. The article may be made by forming a hot dough of the matrix and cellular material, feeding the dough in heat-softened state to an extruder, extruding it under conditions which compress the cellular material but avoid any significant mechanical breakdown or denaturing thereof, and relieving the compression of the cellular material downstream of the die but before the matrix has cooled to a temperature which would prevent this.