Odor-free thermoformed heat-degraded polyvinyl alcohol

Claim 1

AN IMPROVEMENT IN THE STRUCTURE OF THERMOFORMED COLDWATER-SOLUBLE POLYVINYL ALCOHOL WHICH HAS A PERCENT HYDROLYSIS IN THE RANGE OF 74 TO ABOUT 98 AND WHICH STRUCTURE HAS BEEN HEAT-DEGRADED BY SUCH THERMOFORMING TO THE EXTENT THAT SOME FREE ACETIC ACID IS PRODUCED IN THE THERMOFORMED POLYVINYL ALCOHOL AND IS DISTRIBUTED THROUGHOUT SAID THERMOFORMED STRUCTURE, SAID IMPROVEMENT CONSISTING OF THE INCORPORATION THROUGHOUT SAID STRUCTURE BEFORE HEAT DERADATION OF A PROTON ACCEPTOR, SAID PROTON ACCEPTOR BEING SUCH THAT IT HAS A PH IN THE RANGE OF ABOUT 7.5 TO 12.0 WHEN SAID PROTON ACCEPTOR IS ACTIVATED AND IONIZED BY THE PICK-UP OF MOISTURE NORMALLY PRESENT IN THE AMBIENT ATMOSPHERE, SAID PROTON ACCEPTOR BEING PRESENT IN SAID STRUCTURE IN AN AMOUNT SUFFICIENT TO REACT WITH AND TO NEUTRALIZE ANY OF SAID ACETIC ACID WHICH IS ALSO IONIZED WHEN SAID STRUCTURE IS EXPOSED TO THE MOISTURE NORMALLY PRESENT IN THE AMBIENT ATMOSPHERE, SAID PROTON ACCEPTOR BEING PRESENT IN AN AMOUNT OF UP TO ABOUT 5 PARTS BY WEIGHT OF SAID POLYVINYL ALCOHOL STRUCTURE THEREBY PROVIDING A HEAT-DEGRADED POLYVINYL ALCOHOL STRUCTURE WHICH REMAINS SUBSTANTIALLY FREE OF THE ODOR OF SAID ACETIC ACID.