| 摘要 |
In a process for the preparation of elastomeric polyurethane filaments, a liquid urethane prepolymer, comprising the reaction product of excess organic diisocyanate with a hydroxyl-terminated polyester or polyether having at least two carbon atoms between the ether oxygen atoms, is extruded into a coagulating bath containing a 0.05-3 N solution of a polyamine in a hydrocarbon organic solvent, and the filaments so formed are cured in the absence of water. Many polyesters, polyethers, diisocyanates, polyamines and hydrocarbon solvents are specified. The liquid prepolymer mixture may be extruded through a single- or multi-hole spinneret into a bath 3 cms. to several metres in length maintained at e.g. 5-100 DEG C. The extruded filaments then pass over a roll and into an oven where solvent and polyamine are removed by heating, and the filaments are cured. The filaments may move through the oven on a continuous belt. If the temperature of the oven is 175-225 DEG C. or more the curing therein is complete in e.g. 30-60 seconds, and the filament may be led to a lubricant applicator and take-up spool. If a lower temperature, e.g 65 DEG C., is used, curing may be completed by heat-treating the filaments after spooling. The cured filaments may be stretched, e.g. 10-700%. In examples, prepolymers prepared from (1) ethylene glycol/propylene glycol/adipic acid and 2,4-toluene diisocyanate, (2) polycaprolactone and 2,4-toluene diisocyanates, (3) polyethylene/propylene adipate and hexamethylene diisocyanate, (4 and 5) polyethylene/propylene adipate and 2,4-toluene diisocyanate (6) polypropylene glycol and methylene bis-(4-phenylisocyanate), (7) polypropylene glycol and 2,4-toluene diisocyanate are extruded into baths containing 4% ethylene diamine in toluene or benzene, and 0.9% or 5% of piperazine in toluene. |
