Patent ID: 9242398
Filing Date: 2016-01-26
CPC Classification: B29C

Claim Text:
1. A process for producing plastic molded articles with thickened and strengthened walls, comprising the steps of: a) designing a plastic article having at least one cavity or hollow zone to be filled out with strengthening thermoplastic material, and wherein said article is provided with at least one injection gate or an injection zone; b) premolding the plastic article designed in the previous step as at least two separate molded plastic pieces through a molding process, wherein at least one of the at least two separate molded plastic pieces is premolded to at least partially define the at least one cavity or hollow zone therein; c) after the premolding step b), assembling the at least two separate molded plastic pieces to define the at least one cavity or hollow zone of the plastic article between the at least two separate molded plastic pieces; d) after the assembling step c), injecting a thermoplastic material with an expanding or foaming agent, by low-pressure injection equipment, through said at least one injection gate or injection zone, into said at least one cavity or hollow zone of the article previously molded in step b) to completely fill said at least one cavity or hollow zone with the foamed or expanded thermoplastic material; e) withdrawing the plastic article from the low-pressure injection equipment, and providing for the expansion of said foamed or expanded thermoplastic material; f) after the withdrawing step e), fastening the at least two separate molded plastic pieces together with the foamed or expanded thermoplastic material to form the plastic article; and g) carrying out a cooling down of the withdrawn article from an elevated temperature resulting from the injecting step in a storage zone or warehouse, wherein the foamed or expanded thermoplastic material serves to fasten together various sections forming the article, wherein the at least one cavity or hollow zone is covered to prevent the foamed or expanded thermoplastic material to be injected from running out of the at least one cavity or hollow zone, and wherein the plastic article is strengthened in the at least one cavity or hollow zone by the foamed or expanded thermoplastic material.