| abstract |
Dip molding of thermoplastic polyurethane elastomers to form medical and surgical gloves, condoms, instrument and appliance covers, and other rubber goods is improved by a controlled viscosity, controlled rate of evaporation solvent system, including a strong polar solvent, a weak solvent or non-solvent to control viscosity, and a blush resistor to control the rate of evaporation and the effects of humidity. For particularly enhanced barrier film formation, a leveling agent is also included. One or more layers are dipped in sequential steps in thicknesses of 0.5 to 1.5 mils per layer, with complete integral film formation and substantially complete freedom from porosity and pin holes. Cross-linkable polyurethanes may be cured after fully molded. |