Manufacture of thermoplastic sheet material

Abstract

Abstract A PROCESS FOR MAKING A THERMOPLASTIC SHEET WHICH COMPRISES THE STEPS OF PROGRESSIVELY SPREADING A PASTE OF A THERMOPLASTIC MATERIALS UPON CONTINUOUSLY MOVING SILICONE ELASTOMER BAND HAVING A PREDETERMINED SURFACE CONFIGURATION, HEATING THE PASTE THEREBY EFFECTING GELATION OF SAID THERMOPLASTIC MATERIAL AS AN INTEGRAL SHEET AND REMOVING THE HOT SHEET FROM THE BAND. IN PREFERENCE THE SHEET IS PROVIDED WITH A BACKING MATERIAL. THE PROCESS IS PARTICULARLY SUITED TO THE MANUFACTURE OF SHEET FROM PASTES BASED ON POLYMERS OR VINYL CHLORIDE. THE PASTE MAY BE APPLIED ON THE BAND IN TWO DISTINCT APPLICATIONS USING DIFFERENT PASTES FOR EACH APPLICATION. TYPICALLY A FIRST LAYER IS FORMED ON THE BAND USING A PASTE WHICH DOES NOT INCLUDE A BLOWING AGENT AND THEN A SECOND LAYER IS FORMED ON TOP OF THE FIRST LAYER USING A PASTE WHICH INCLUDES A BLOWING AGENT. WHEN THE DOUBLE LAYER IS HEATED THE BLOWING AGENT DECOMPOSES FORMING A MULTITUDE OF CELLS IN THE SECOND LAYER AND AT THE SAME TIME THE FIRST AND SECOND LAYER ARE GELLED. THE SILICON ELASTOMER BAND MAY HAVE A SMOOTH OR CONTOURED SURFACE PATTERN. ALSO THE HOT SHEET MAY BE EMBOSSED IMMEDIATELY AFTER IT IS REMOVED FROM THE BAND.

Inventors

• 👤 Alan Duerden
• 👤 Samuel Gourley

Bibliographic Details