Orthopaedic dressing material for broken limbs and joints or dressing wounds - comprises water-curable polyurethane prepolymer contg. maleic anhydride stabiliser and alpha morpholino ethoxy beta ethoxy-morpholino:ethane-anhydrous potassium carbonate mixt. catalyst

摘要

Orthopaedic dressing material (I) comprising a water-curable polyurethane prepolymer (A) supported on a synthetic or glass fibre mesh fabric. The novelty of the invention is that the prepolymer contains maleic anhydride (B) as a stabiliser and a mixt. of alpha-morpholino ethoxy-ethoxy-beta- morpholinoethane (C) and anhydrous potassium carbonate as a catalyst. (A) pref. contains 0.1-5.0 wt.% (B), added to (A) as an organic solvent soln., 0.1-3.0 (C) and 1-10 anhydrous potassium carbonate, mixed as a powder having a particle size less than 100 microns, all wrt. total wt. of (A). (A) pref. contains diphenylmethane diisocyanate (contg. carbodiimide) as isocyanate component and dihydroxy polyether or a mixt. of dihydroxy- and trihydroxy polyether as polyhydroxy component, the ratio of NCO-OH equivs. being 3-6:1. (I) is pref. prepd. by applying (A) contg. stabiliser and catalyst to the synthetic or glass fibre mesh fabric substrate. The prepn. comprising addition of material, application, rolling up, cutting and packaging, pref. takes place in a dry nitrogen atmos. with a strictly controlled low humidity level (less than 100ppm and pref. less than 50ppm water content). The mesh fabric pref. comprises fibres having a thickness of 0.01-0.5cm and contains 15-30 mesh holes per cm2. USE/ADVANTAGE - (I) are useful for fixing broken limbs or joints and for dressing patients wounds (claimed). The addn. of (B) to (A) prevents premature curing of (I) during use or storage. The solubility of (B) in organic solvents means that it may be readily added during the prepn. of (A), thereby increasing the storage life of (I). The use of (C) in the catalyst mixt. results in far fewer by prods. than in the prior art and increases the storage life of (I).