Small calibre vessel prosthesis prodn. - from polyurethane, fine mesh polyester knitted tube and silicone rubber, using coated polyethylene tube as former

摘要

A polyethylene tube is wrapped in a preformed tape of submucosa or serosa from sheep or cattle or provided with a coating of dissolved collagen or a protein coating of dissolved gelatin, which is allowed to dry. It is then coated by immersing several times in a polyester - or polyetherurethane or copolymer soln. in DMF and xylene and allowed to dry, whilst turning, and then dried for several hrs. in a thermostat at ca 90 degrees C. The ca 20 um thick polyurethane film obtd. is given a 0.1-0.2 mm thick silicone rubber coating by immersing several times in a 10-20% silicone rubber soln. drying well at ca. 40 degrees C and completed polymerisation. A knitted tube of very fine polyester yarn, with a mesh size of ca. 0.15 mm2, is drawn over the silicone rubber coating and embedded in silicone rubber by repeated dipping. A 0.2-0.6 mm polyurethane filament is wound spirally over the tube, the winding spacing corresp. to the filament dia. then the tube is coated with silicone rubber soln. again to lock the filament. Finally to give a completely smooth inner surface, the prosthesis is briefly immersed in a 1-2% soln. of polyurethane in DMF and xylene in 8:7 ratio and dried several hrs at ca 90 degrees C. Removal of the polyethylene tube gives a tube with the required dia. which is accurate, can be of any size and can be made conical.