The present invention relates to an emulsion for the treatment of cellulose filaments after spinning and a method for the preparation of cellulose filaments with use of the emulsion.
Usually, in the preparation of viscose rayon filaments by a centrifugal spinning process, the cake is treated with an emulsion, dehydrated and then dried in a tunnel drier for 70 to 100 hours. The cake should be dried at a low temperature under a high moisture to be dried uniformly throughout its inside and outside. Generally, the external part of the cake is wound densely under tension so that it is difficult to shrink during drying and tends to form internal strain when dried suddenly, while the internal part of the cake is wound under low tension so that it tends to shrink by drying and forms no internal strain. Accordingly, the quality of the filaments is largely affected by the drying temperature and the drying speed.
Accordingly, by a rapid drying method, the surface of the cake is easily dried to form a shrinking force. However, since the surface of the cake cannot shrink freely, it is dried under tension to form internal strain. Further, the shrinkage is uneven between the inside and the outside of the cake, and resultantly a difference in fineness between them occurs. In some cases, a high frequency heating system is used to dry uniformly the cake throughout its inside and outside, but it requires disadvantageously a high manufacturing cost.
Conventionally, a nonionic emulsion or a mixture of a nonionic emulsion and an anionic emulsion has been used for the emulsion treatment of cellulose filaments after spinning, and recently with the high development of surface active agents an anionic or a nonionic emulsion or their combination has been used as the base in many cases. However, no cationic surface active agent has been used.
An object of the present invention is to provide an emulsion for treatment of cellulose filaments such as viscose rayon filaments and acetate filaments after spinning, which reacts easily with cellulose molecule in the amorphous area of the fiber and thus lowers its swelling degree and makes free shrinkage possible along the progress of drying.
Another object of the present invention is to provide a method for preparation of an excellent filament having uniform fineness, smooth surface, naturally increased twist and increased tensile strength by using such an emulsion.