Lyocell multifilament
The present invention relates to a high tenacity, high modulus and low shrinkage lyocell multifilament yarn suitable for use in tire cords and MRG (mechanical rubber goods). The lyocell multifilament yarn is a cellulose-based fiber for industrial applications, which is produced by dissolving pulp having a degree of polymerization (DP W ) of 700-2,000 and preferably 800-1,400, and a α-cellulose content of more than 90% and preferably more than 92%, in N-methylmorpholine N-oxide (NMMO) hydrate, at a pulp concentration of 5-15% by weight and preferably 8-13% by weight. The lyocell monofilament according to the present invention is characterized by the following stress-strain profile: (1) the lyocell monofilament analyzed after drying is elongated by less than 3.0% and has an initial modulus of 150-400 g/d, when it was subjected to an initial stress of 3.0 g/d; (2) it is elongated by 3.0-7.0% when it was subjected to a stress greater than the initial stress but smaller than 6.0 g/d; and (3) it is elongated from a tensile tenacity of at least 6.0 g/d until the yarn is broken.
1. A lyocell monofilament, which has a stress-strain curve wherein:
(A) the lyocell monofilament analyzed after drying is elongated by less than 3.0% and has an initial modulus of 150-400 g/d, when it was subjected to an initial stress of 3.0 g/d;
(B) it is elongated by 3.0-7.0% when it was subjected to a stress greater than the initial stress but smaller than 6.0 g/d; and
(C) it is elongated from a tensile tenacity of at least 6.0 g/d until the yarn is broken.
2. A lyocell multifilament, which consists of an aggregate of 40-4,000 lyocell monofilaments of claim 1 .
3. The lyocell multifilament of claim 2 , wherein the heat shrinkage of the lyocell multifilament is 0.1-3.0%.
4. The lyocell multifilament of claim 2 , wherein the tensile tenacity of the lyocell multifilament is 4.5-10.0 g/d.
5. The lyocell multifilament of claim 2 , wherein the number of interlacing per meter in the lyocell multifilament is 2-40.
6. A lyocell tire cord produced by a method comprising the steps of: twisting the lyocell multifilament of claim 2 with a twisting machine to produce a greige cord; and dipping the greige cord in a dipping solution.
7. A tire comprising the lyocell tire cord of claim 6 at a carcass or a cap ply.
8. A hose comprising the lyocell multifilament of claim 2 as a reinforcement material.
9. A belt comprising the lyocell multifilament of claim 2 as a reinforcement material.