According to the manufacturer, a spunbond polybutylene terephthalate (PBT) produces fabrics that shrink less during processing and are softer and more flexible than those made with traditional polyethylene terephthalate (PET) polymers. Ticona (Summit, NJ; 908/598-4199) reports that its new PBT grade, Celanex 2000-K, also produces finer denier fibers than PET. In pilot trials, measurements of around 2.0 deniers per filament were obtained from the PBT. When Celanex 2000-K is blended with PET, it reduces the stiffness of PET spunbond fabrics. Celanex 2000-K has a melt processing temperature of 260° to 280°C. It also crystallizes more readily and rapidly than PET, which, according to Ticona, allows it to be run on high-volume polypropylene-spunbond machines. The company can also modify the viscosity of its PBT polymers for bicomponent processing.