Size-covered composite yarns and method for making same
View Patent ↗Composite yarns, comprising one or more elastomeric fibers and hard yarns, are formed by adhering the elastomeric fibers and hard yarns together using a size material. The size-covered composite yarn can be used in weaving and knitting to make stretch fabrics with desired garment characteristics. The size material may be removed by subsequent wet fabric processing.
1. A method for making a composite yarn, comprising:
stretching a strand of one or more elastomeric fibers in a range from 1.1× to 5× of a relaxed length of the strand;
aligning at least one hard yarn selected from the group consisting of synthetic fibers, natural fibers and a blend of synthetic and natural fibers, adjacent and substantially parallel to said stretched strand to form an aligned yarn;
applying a size material to said aligned yarn, wherein said size material comprises a sizing agent and optionally a wax, further wherein said size material is applied to said yarn by an aqueous or hot-melt process, and when said sizing agent is applied by an aqueous process, said size material is dissolved in water to form a solution before the size material is applied to the aligned yarn wherein concentration of the size material in the solution is from 5% to 25% by weight, and when said sizing agent is applied by a hot-melt process, said size material is applied to the aligned yarn in an amount from 3% and 6% by weight based on the aligned yarn pre-sized weight, and when wax is present in said size material, said wax is present in amounts not exceeding 1 weight % based on the solids weight of the sizing agent; and
drying or curing the size material to form a composite yarn.
2. The method of claim 1 , further comprising entangling surface fibers of the at least one hard yarn aligned with said strand of one or more elastomeric fibers, wherein said entangling is done prior to applying a size material to the aligned yarn.
3. The method of claim 1 , wherein the strand comprises a spandex yarn of a denier of from 20 to 140, and wherein the hard yarn has a total denier of from 45 to 900.
4. The method of claim 1 , wherein said sizing agent is selected from the group consisting of: starch, acrylic polymer, PVA and CMC.
5. The method of claim 1 , wherein the sizing agent is applied by a hot-melt process and is a hot-melt polymer.
6. The method of claim 4 , wherein the size material is applied by an aqueous process.
7. The method of claim 5 , wherein the hot-melt polymer is selected from the group consisting of: acrylate ester and methacrylate ester, and wherein the concentration of wax, if present, is up to 1% by weight.