LYOCELL MULTI-FILAMENT FOR TIRE CORD HAVING EXCELLENT STRENGTH AND MODULUS, AND MANUFACTURING METHOD THEREOF

摘要

PURPOSE: Lyocell multi-filament for a tire cord has excellent physical properties like strength and modulus. A tire for a car manufactured out of the lyocell multi-filament has improved drive stability, dimensional stability and uniformity. CONSTITUTION: Lyocell multi-filament is obtained by the steps of: (i) dissolving powder mixed cellulose and PVA into a mixed solvent of N-methyl morpholine N-oxide(NMMO)/water to manufacture a dope; (ii) extrusion-spinning the dope through a spinning nozzle(2) containing many orifices; passing the fiber type dope through an air area to reach an upper conic coagulating bath(4), followed by coagulating the dope to manufacture multi-filament; (iii) supplying the multi-filament to a lower coagulating bath(8); changing an advance direction of the multi-filament to wash the multi-filament into a washing bath; and then (iv) drying, oiling and winding the washed multi-filament. The lyocell multi-filament has (1) 5-10g/d of strength, (2) 3-13% of elongation, (3) 200-400g/d of modulus, (4) 0.038-0.050 of birefringence, (5) 40-52 of crystallinity, (6) -0.5-3% of shrinkage, (7) at least 90% of tenacity maintenance rate after treating saturated steam of high temperature and (8) 1000-2500denier of fineness. The orifices have 100-300μm of diameter, 200-2400μm of length, 2-8 of rate(L/D) of the diameter and the length and 2.0-5.0mm of intervals between the orifices.