Method of manufacture of foamed thermo-plastic extruded shapes
AssigneeSociete Chimique des Charbonnages S.A.
InventorGuy Lozach
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Abstract
The present invention relates to a method of manufacture of profile-sections of any shape, including complex shapes, of structural foamed thermo-plastic material, having a density of between 0.4 and 0.9 with respect to the corresponding bulk or solid thermo-plastic material, the said method consisting in slowing-down and/or stopping the expansion at the immediate outlet of a conventional extrusion machine, at predetermined zones by blowing or spraying, in a differential manner at the periphery of the extruded product, a fluid at a temperature lower than the softening temperature of the said thermo-plastic material.
Claims10
A method for the extrusion-manufacturing of a diversity of structural foamed thermoplastic material shaped sections of indefinite length and having a density of 0.4 to 0.9 with respect to the corresponding solid thermoplastic material, said method comprising:
- extruding a foamable thermoplastic material from an extruder through a die orifice with an initial shape section the material beginning to expand at the outlet of said die;
- modifying the shape-section of the expanding extrudate by partially slowing-down or stopping the expansion in pre-selected zones of said extrudate immediately at the outlet of said die orifice by differently cooling said zones with a plurality of jets of cooling fluid under pressure and having a temperature lower than the softening temperature of the thermoplastic material, said jets having a peripheral distribution, constituting a fluid shaping device, while permitting the expansion to continue in the non-cooled zones, whereby an extrudate having a shape-section different from that of said initial die shape is formed,
- and finally fixing the resulting shape by cooling.
Dependencies are inferred from the claim text.