Method of extruding a foamed plastic tube having internal and external skins thereon

• US 3,299,192 A
• Filed: 06/11/1963
• Issued: 01/17/1967
• Est. Priority Date: 06/11/1963
• Status: Expired due to Term

• Current Assignee: John H. Lux
• Original Assignee: John H. Lux
• Inventors: Lux, John H.
• Application Number:
  US04/287,128
• Time in Patent Office: 1,316 Days
• US Class Current: 264/48
• CPC Class Codes: B29C 44/507 extruding the compound through an annular die in general B29C48/03
• CPC Class Codes: B29C 48/09 Articles with cross-sections having partially or fully enclosed cavities, e.g. pipes or channels
• CPC Class Codes: B29C 48/10 flexible, e.g. blown foils
• CPC Class Codes: B29C 48/21 the layers being joined at their surfaces
• CPC Class Codes: B29C 48/335 Multiple annular extrusion nozzles in coaxial arrangement, e.g. for making multi-layered tubular articles
• CPC Class Codes: B29L 2023/00 Tubular articles B29L2024/00 takes precedence ; catheters B29L2031/7542

Claims

1. A METHOD OF FORMING A TUBULAR EXTRUSION OF A THERMOPLASTIC RESIN FORM COMPRISING EXTRUDING A HOT HOLLOW TUBE OF A FOAMABLE THERMOPLASTIC RESIN, QUENCH CHILLING THE EXTERNAL WALL OF SAID TUBE BY FLUID CHILLING MEANS SURROUNDING SAID WALL WITHIN A SHORT TIME AFTER IT EMERGES FROM THE EXTRUSION DIE TO FORM AN IMPERVIOUS, NON-POROUS, EXTERNAL SKIN, QUENCH CHILLING THE INTERNAL WALL OF SAID TUBE BY FLUID CHILLING MEANS SURROUNDED BY SAID WALL WITHIN A SHORT TIME AFTER IT EMERGES FROM THE EXTRUSION DIE TO FORM AN IMPERVIOUS, NON-POROUS, INTERNAL SKIN, SAID CHILLING OF SAID EXTERNAL AND INTERNAL WALLS BEING INSUFFICIENT TO COOL THE MAJOR PORTION OF THE TUBE WHEREBY THE CORE OF THE TUBE EXPANDS TO FORM A FOAM, SAID CORE BEING 50 TO 94% OF THE THICKNESS OF SAID TUBE.