摘要 |
Cigarette filters with improved efficiency and reduced resistance to gas flow, and a method of preparing them, are disclosed. The filters are made from crimped multicomponent polypropylene polymers having microfissures on their surfaces and micropores on their cross-sections, with 5 to 7 crimps per centimeter of length, and a unit fineness of 5 to 7 dtex. The elementary fibers in the bundle have different centers of gravity, and are present in ratios of from 1:3 to 3:1 by weight. The fibers are prepared by separate melting and thermal treatment of each polypropylene polymer component, having LVI values ranging from 100 to 200 ml/g, at temperatures ranging from 230 to 330 degrees C. The difference in LVI values between the components is from 30 to 50 ml/g, and at least one of the components has a 5-20% high molecular weight fraction, by weight, with an LVI of from 400 to 450 ml/g. Each component is homogenized separately, after which they are mixed from a nonhomogeneous flow of melts and extruded into a bundle through 3000 to 10,000 orifices in a spinneret. The bundle, or sliver, is treated with water, relaxed and fixed at a temperature of 70 to 140 degrees C., wrapped with paper, and cut into filters. |
申请人 |
VYSKUMNY USTAV CHEMICKYCH VLAKEN |
发明人 |
R. SIMO, S. BACULAK, L. KNOTEK, J. PECIAR, I. MITTERPACH, J. HUDAK, J. SIMO, J. BADURA, V. BESEDA, F. MIHALY, A. GREGOR ET J. KLISKY;BACULAK S;KNOTEK L;PECIAR J;MITTERPACH I;HUDAK J;SIMO J;BADURA J;BESEDA V;MIHALY F;GREGOR A;KLISKY J |