Stabilization of polyoxymethylenes with aromatic amines

Claim 1

THE THERMALLY STABILIZED POLOXYMETHYLENE COMPOSITION WHICH COMPRISES A NORMALLY SOLID, SYNTHETIC, HIGH MOCELCULAR WEIGHT POLOXYMETHYLENE SELECTED FROM THE GROUP CONSISTING OF (1) POLOXYMETHYLENES HAVING A DEGREE OF TOUGHNESS OF AT LEAST 1, SAID DEGREE OF TOUGHNESS OF AT LEAST 1 BEING DETERMINED BY THE CONSECUTIVE STEPS OF COMPRESSION-MOLDING SAID POLOXYMETHYLENE INTO A FILM 3 TO 7 MILS IN THICKNESS, HEATING SAID FILM IN AIR AT 105* C. FOR 7 DAYS, COOLING SAID FILM TO ROOM TEMPERATURE AND WHILE MAINTAINING SAID FILM TO ROOM TEMPERATURE, MANUALLY FOLDING AND CREASING SAID FILM ALONG A LINE, AND MANUALLY FOLDING AND CREASING SAID FILM IN THE REVERSE DIRECTION ALONG THE SAME LINE WITHOUT A BREAK OCURRING IN THE FILM ALONG SAID LINE, AND (2) POLOYOXYMETHYLENES FAILING TO EXHIBIT A DEGREE OF TOUGHNESS OF AT LEAST 1, BUT HAVING A REACTION RATE CONSTANT FOR THERMAL DEGRADATION AT 222* C. OF LESS THAN 1% BY WEIGHT PER MINUTE, MEASURED BY THERMALLY DEGRADING SAID POLOXYMETHYLENE IN A VESSEL OPEN TO THE ATMOSPHERE, AND 0.001%-10% BY WEIGHT OF SAID POLOXYMETHYLENE OF A THERMAL STABILIZING COMPOUND FROM THE GROUP CONSISTING OF MONOMERIC SECONDARY AROMATIC AMINES AND MONOMERIC TERTIARY AROMATIC AMINES, SAID THERMALLY STABILIZED POLYOXYMETHYLENE COMPOSITION BEING CHARACTERIZED IN THAT SAID COMPOSITION EXHIBITS A GREATER DEGREE OF THERMAL STABILITY THAN DOES SAID POLOXYMETHYLENE IN THE ABSENCE OF SAID THERMAL STABILIZING COMPOUND.