METHOD FOR PRODUCING SHAPED ARTICLES OF POLYOLEFINS CONTAINING ANISOTROPIC FILLER USING BLOW MOULDING TECHNIQUES

摘要

Articles are blow molded from thermoplastic polymeric materials containing high proportions of fillers such as glass fibres. The method comprises extruding the filled polymeric material through a die having a mandrel for constraining the material into a tubular shape, coextruding between the die and the outer surface of the material, a liquid having a freezing temperature lower than that of the material, cooling the liquid and the outer surface of the material during their passage through the die to a temperature below the freezing temperature of the material but above the freezing temperature of the liquid while maintaining the inner surface of the material molten, squeezing the extrudate at suitable intervals to fuse the molten inner surface together and thereby seal discrete lengths, and inflating the sealed lengths to conform to a surrounding mold to produce a shaped article. Lamina shapes may be foam-filled to give stiff panels.