| 摘要 |
1476545 Dyeing leather yarns E I DU PONT DE NEMOURS & CO 14 Feb 1975 [15 Feb 1974] 6399/75 Heading D1B [Also in Division B4] A leather yarn comprises a dyed assembly of two types of filaments. One is a sheathcore composite filament in which the sheath and the core are made from different thermoplastic polymers and the other is a homofilament composed of the same polymer as the core. The yarn is produced by the simultaneous extrusion of the two polymers in an appropriate fashion (see B5 abridgment). The two polymers are chosen so that one class of dye will dye one but not the other and so that a second class of dye will dye both. It is preferred to use, as the first class of dyes, acidic or basic dyes and disperse dyes as the second. It is also preferred to use as the sheath polymer one which is not dyeable by the acidic or basic dyes chosen, but to use a core polymer that is. Both polymers should respond to the disperse dye. In such a case, the sheath protects the core from the acidic or basic dye, which thus dyes the homofilaments only, whereas the disperse dye, to which the sheath is susceptible, penetrates and dyes both the sheath and the core, thus avoiding ring-dyeing effects in the conjugate filament and so providing a yarn composed of filaments having two different colours. In Examples I and II the core/homofilament polymer is a copolymer of ethylene terephthalate and 5-(sodium sulpho) isophthalate and the sheath polymer is polyethylene terephthalate. Three dye-bath compositions are given, all containing a basic dye to which the core polymer, but not the sheath, is susceptible. In Example III, the core/homofilament polymer is poly (hexamethylene adipamide) and the sheath is poly (ethylene terephthalate). The filaments are boiled in one of two dyebath compositions, C.I. ABL107 being used as the dye selective for the core polymer in both. |
