Polyurethane-urea solns. for mfr. of e.g. surgical gloves - have specified polymer content and soln. viscosity, with polymer prepd. from specified reactants

摘要

Improved organic solvent solns. of polyester- or polyether-urethane ureas for prodn. of thin-walled elastic articles are free of metal chlorides and are such that the polymers are made by reacting an organic diisocyanate and polymeric diol of Mn 3000-6000 to give prepolymer of 1.4-2 % NCO end gp. content which is then reacted with a diamine, the improvements being that (i) the polyurethane urea concn. is 12-20 wt. % in the soln.; and (ii) the soln. viscosity is 2.5-12.5 Pa.s. with the provisos that (a) the polyester-urethane ureas are made by reaction of methylene bis(4-phenyl- (or cyclohexyl)-isocyanate) with a polyester diol obtd. by reaction of 80-20 pts. wt. adipic acid with 20-80 pts. wt. ethylene glycol + 1,4-butylene glycol; and (b) the polyetherurethane ureas are made by reaction of methylene-bis-(4-phenylisocyanate) with a polyether diol which comprises a 96/4-80/20 THF/3-Me-THF copolymer. The polyurethane urea concn. is pref. 14-17 % and the soln. viscosity is 5-10 Pa.s. The polyester-urethane ureas are made from ethylene glycol and 1,4-butylene glycol at wt. ratio pref. of 40:60-75:25, with the chain extender being 1,3-diaminocyclohexane or ethylenediamine. The chain extender for the polyetherurethane-ureas is ethylenediamine. USE/ADVANTAGE - Uses gloves made from the soln. are claimed, specifically those with thickness 0.05-0.08 mm, piercing strength at least 87 N/cm, hardness no more than 15 % and a tearing strength of at least 87 N/m. Such gloves are used as surgical gloves. Gloves etc. can be made without the need for chemical hardening and without the need to dissolve-out spandex (RTM) fibres. Properties are better than those of gloves made from rubber latex.