Core-free thermoplastic polyurethane yarn with added nanosilica

#The present invention generally relates to a thermoplastic polyurethane (TPU) and more particularly to core-free thermoplastic polyurethane yarns with added nanosilica.

#The yarns for footwear upper and similar industrial products are mostly formed of polyester, nylon, acryl resin, or the like. The fabrics processed from those yarns are not only poor in durability and wear resistance, but also problematic in many aspects including adhesiveness, so they are unfit to use for high level functionality such as of footwear fabrics or the like.

#Currently, a solution to this problem is a yarn (hereinafter, referred to as “coated yarn”) the surface of which is coated with a thermoplastic resin in order to enhance the strength of the yarn. Such a coated yarn is generally fabricated by applying a coating of a thermoplastic resin such as PVP or PP or a thermoplastic polyurethane resin on a yarn like polyester or nylon in a dice using a general extruder.

#Hereinafter, various embodiments of the present invention will be described in detail. In the following description, representative examples will be provided for practicing corresponding embodiments of the invention to achieve the described technical solutions and results.

#The term “nanosilica”, as used herein, means silica having a primary particle size of 100 nm or less, and the term “yarn”, as used herein, refers to a core-free (mono- or multi-filament) TPU yarn, where the TPU comprises an added nanosilica. Furthermore, the term “producing TPU yarns continuously” means continuously drawing TPU yarns without thread breakage (or substantially without thread breakage).

#The present invention is to realize a resin for thermoplastic polyurethane yarn using nanosilica and a method for manufacturing a thermoplastic polyurethane yarn using the same, where nanosilica having a particle size of 100 nm or less is added as a thickening agent for improving productivity and glossiness in the production of thermoplastic polyurethane yarns (preferably, mono- or multi-filament yarns using core-free TPU with added nanosilica). Specifically, this can provide an opportunity for the production of thin TPU yarns, such as mono-filament TPU yarns having a denier count of 50 to 350 and multi-filament TPU yarns having a denier count of 50 or less without applying a coating of TPU to the surface of polyester or nylon yarns as disclosed in the above-mentioned prior patents, thereby securing desired workability and properties and realizing continuous drawing of TPU yarns without thread breakage (or substantially without thread breakage).