| 摘要 |
Fibres and films of synthetic linear polymerization or polycondensation products, e.g. polyamides, polyurethanes, polyesters, polyethylene and vinyl polymers, are brought into a slightly swollen condition and thereafter (before or after drying) subjected to ionizing radiation, e.g. with electrons, neutrons or gamma rays. By this means heat-shrinkage is reduced without a substantial reduction in strength. "Slightly swollen" means that the material swollen contains not more than 25% of the swelling agent. The irradiation may take place at normal or elevated temperature, preferably with the material under tension just less than that required for permanent deformation, and preferably after the material has been subjected to any final stretching. In an example a thread of nylon (840 denier) is swollen in water for 24 hours at 20 DEG C. and then led around two non-parallel rollers in a helical path at 4 metres/minute and under a tension of 50 grams while being subjected to a dose of 5 X 106 rep. by an electron beam. The shrinking tension and loss of strength of the treated product are compared with those of products (a) irradiated but not swollen; (b) swollen but not irradiated; (c) not treated.ALSO:Products made from synthetic linear polymerization or polycondensation products, e.g. fibres and films of polyamides, polymethanes, polyesters, polyethylene and vinyl polymers, bottles and gear wheels are brought into a slightly swollen condition and thereafter (before or after drying) subjected to ionizing radiation e.g. electrons, neutrons, g rays. By this means heat-shrinkage is reduced without a substantial reduction in strength. The irradiation may take place at normal or elevated temperature, preferably with the product under tension just less than that required for permanent deformation and preferably after the products have been submitted to any final plastic deformation, e.g. stretching. In an example a thread of nylon (840 denier) was swollen in water for 24 hours at 20 DEG C. and then led around two non-parallel rollers in a helical path at 4 metres/min. and under a tension of 50 grams while being subjected to an irradiation dose of 5 X 106 rep. by an electron beam. The shrinking tension and loss of strength of the treated product are compared with those of products (a) irradiated but not swollen; (b) swollen but not irradiated; (c) not treated. |
