Patent ID: 7151141

Claim:
A method for stabilizing a fluorine-containing polymer having terminal carboxylic acid groups or terminal groups that generate the terminal carboxylic acid groups on heating at a temperature of at least 200° C. comprising the steps of: adding 0.1 to 10% of a compound comprising an alkali metal or an alkaline earth metal in terms of the number of atoms of the alkali metal or the alkaline earth metal based on the total number of the above terminal groups, 0.1 to 10% of ammonia in terms of the number of ammonia molecules based on the total number of the above terminal groups, or 0.1 to 10% of a compound having an ammonium group in terms of the number of the ammonium groups based on the total number of the above terminal groups to the fluorine-containing polymer, and heating the fluorine-containing polymer at a temperature of at least 200° C. in an atmosphere containing moisture while melt kneading said fluorine-containing polymer.