PROCESS FOR DECREASING THE GAS AND WATER-VAPOR PERMEABILITY OF CLEAR TRANSPARENT FOILS AND HOLLOW BODIES MADE OF AMORPHOUS POLYAMIDES

摘要

1287988 Coated polyamide articles DYNAMIT NOBEL AG 30 Oct 1970 [31 Oct 1969] 51854/70 Heading B2E The gas and/or steam permeability of a shaped body formed on an amorphous polyamide is reduced by immersing the shaped body in a dispersion of 55-20 parts by weight of a copolymer of 85-90 parts by weight vinylidene chloride and from 15-10 by weight of ethyl acrylate in from 45-80 parts by weight of water, and drying the body in a current of air having an elevated temperature. The shaped body may be degreased prior to immersion in the copolymer dispersion by dipping in a solvent for the greasing agent. The preferred polyamides are those prepared from terephthalic acid and 2, 2, 4 and/or 2, 4, 4-trimethyl hexamethylene diamine containing 0-30% by weight of hexamethylene diamine. The shaped bodies may also comprise blends of the amorphous polyamides and 1-40% of a partially crystalline polyamide, e.g. poly-eaminocaprolactam, a polymer of adipic acid or sebacic acid and hexamethylene diamine, poly-omega-aminoundecanoic acid or polyglycerol trilaurate lactam. The shaped bodies may be in the form of hollowed bodies and films or foils. The polyamides and/or the dispersions may contain 0.1-3% of a light-protective agent, e.g. 2-hydroxy-4-n-octoxybenzophenone, 2, 2 - dihydroxy - 4 - methoxy benzophenone, 2 - (2 - hydroxy - 3, 5 - di. tert. butylphenyl) - benztriazole or methyl - 2 - cyano - 3 - (4 - methoxyphenyl) - crotonate.