B29C 44/0415

Shaping by internal pressure generated in the material, e.g. swelling or foaming {; Producing porous or cellular expanded plastics articles} for articles of definite length, i.e. discrete articles consisting of at least two parts of chemically or physically different materials, e.g. having different densities {by regulating the pressure of the material during or after filling of the mould, e.g. by local venting}