Patent ID: 8173558

Claim:
A polyurethane elastomeric filament-containing weft knit fabric obtained by providing a polymer obtained by reacting a diisocyanate-terminated prepolymer (A) and a dihydroxy-terminated prepolymer (B), the diisocyanate-terminated prepolymer (A) being obtained by reacting a first polymeric diol, having a number-average molecular weight of 800 to 4000, and a first diisocyanate, the dihydroxy-terminated prepolymer (B) being obtained by adding a second polymeric diol, having a number-average molecular weight of 800 to 4000, to a second diisocyanate to produce a diisocyanate-terminated precursor, and subsequently adding a low-molecular-weight diol having a molecular weight of 500 or less to the precursor, melt spinning the polymer without prior solidification to obtain a bare yarn of highly fusible, alkali-resistant polyurethane elastomeric filament having at least 50% retention of tenacity following dry heat treatment under 100% extension at 150° C. for 45 seconds, a melting point of 150 to 175° C., and at least 60% retention of tenacity following treatment in a 2 g/L aqueous sodium hydroxide solution under 100% extension at 100° C. for 60 minutes, separately feeding (i) the bare yarn and (ii) at least one type of non-elastomeric yarn, in order to form a weft knit fabric having a 1×1 rib knit structure by plating, such that the bare yarn is plated on the non-elastomeric yarn at every loop of the weft knit fabric, and then dry heat setting the plated structure at a temperature of 140 to 200° C. for 10 seconds to 3 minutes so as to thermally fuse the filaments of the bare yarn to each other or to the non-elastomeric yarns at crossover points therebetween, wherein 100 wt % of the total polymeric diol is polyether diol, and wherein the fabric has cut edges which are left in an as-cut state.