| 摘要 |
The suture material comprises virtually isotactic polypropylene having a linear density of from 30 to 3000. The polypropylene has the following other properties: tensile strength: from 4.3 to 7.5 gpd (gram per denier) knot strength: from 3.0 to 5.0 gpd percentage elongation at break: from 20.0 to 30.0 Young modulus: from 0.380 to 0.668 x 10<5> kg/cm<2> (from 5.4 to 9.5 x 10<5> psi) or from 50 to 80 gpd flexural fatigue strength (cycles to fracture): F = 1.251 x 10<8> x D<-1.77>, in which D = denier static creep deformation - percentage elongation: < 8.0. The suture material is produced by (a) extruding a virtually isotactic polypropylene at temperatures of from 232 to 288 DEG C to give a filament, (b) quenching the resultant filament in a liquid at a temperature of from 52 to 80 DEG C with simultaneous stretching by a factor of from 1.0 to 5.0 x, (c) subsequently passing the quenched and stretched filament through a heating and stretching zone at a temperature of about 96 DEG C with stretching by a factor of from 5.0 to 8.0 x, (d) subsequently passing the heated and stretched filament through a second heating and stretching zone at a temperature of from 149 to 232 DEG C for its final stretching by a factor of from 0.95 to 1.6 x, and (e) finally obtaining the suture material formed in this way.tu |
