Process of making plates and sheets of polyvinyl chloride fragments by a simultaneous heat and pressure treatment

Claim 1

A PROCESS FOR MAKING PLATES AND SHEETS FROM FRAGMENTS OF POLYVINYL CHLORIDE, BY A SIMULTANEOUS HEAT AND PRESSURE TREATMENT, SAID PROCESS CONSISTING OF APPLYING AN EVEN LAYER OF POLYVINYL CHLORIDE FRAGMENTS ON THE LOWER PLATEN OF A FIRST PRESS, BOTH PLATENS BEING CONTINUOUSLY HEATED AT A FIXED TEMPERATURE COMPRISED BETWEEN 200*C. AND 3300*C., APPLYING ON SAID LAYER IN SAID FIRST PRESS, A PRESSURE FROM 2 TO 5 KG./CM.2, SAID PRESSURE BEING NO MORE THAN SUFFICIENT TO OBTAIN A THICKNESS NO GREATER THAN THE DIAMETER OF THE LARGER FRAGMENTS; RELEASING THIS PRESSURE ONLY WHEN THE POLYVINYL CHLORIDE PREDETERMINED BETWEEN 10 MINUTES AND 300 SECONDS, SO AS SCARCELY UNDER THEIR DECOMPOSITION POINT, SO AS TO BE AGGLOMERATED WITH EACH OTHER WITHOUT BEING ALTERED, THE PRESSURE BEING SO APPLIED ON THE LAYER OF POLYVINYL CHLORIDE FRAGMENTS IN SAID FIRST PRESS DURING A TIME WHICH IS PREDETERMINED BETWEEN 10 MINUTES AND 300 SECONDS, SO AS TO BE LONGER AS SAID LAYER IS THICKER AND AS THE TEMPERATURE OF THE PRESS PLATENS IS LOWER; TRANSFERRING THE LAYER OF AGGLOMERATED POLYVINYL CHLORIDE FRAGMENTS JUST AFTER THE PRESSURE RELEASE FROM THE FIRST PRESS RAPIDLY INTO A SECOND PRESS, THE PLATENS OF WHICH ARE CONTINUOUSLY AT A SUBSTANTIALLY LOWER TEMPERATURE THAN THE PLATENS OF SAID FIRST PRESS; APPLYING FINALLY TO SAID LAYER OF AGGLOMERATED POLYVINYL CHLORIDE FRAGMENTS A PRESSURE NEAR TO THE PRESSURE APPLIED THEREUPON IN THE FIRST PRESS; AND RELEASING THIS FINALLY APPLIED PRESSURE WHEN SAID LAYER HAS RETURNED TO THE AMBIENT TEMPERATURE.