PROCESS FOR SURFACE MODIFICATION OF CRYSTALLINE AND AMORPHOUS THERMOPLASTIC MATERIALS Russian patent published in 1995 - IPC

FIELD: manufacture of polymeric containers. SUBSTANCE: the treatment with sulfur dioxide in admixture with an inert solvent is carried out in 2-5 stages and thermal treatment is accomplished at a temperature of 26-35 C lower than the melting temperature for crystalline thermoplastic materials and at a temperature ranging from the glass transition temperature to a temperature 10 C lower than the glass transition temperature for amorphous thermoplastic materials. The total treatment time is 1-40 minutes. EFFECT: reduced sulfuration and lower permeability of low-molecular compounds. 3 tbl