Patent Publication Number: US-2017350045-A1

Title: Multilayer coated multicolor yarn and manufacturing method thereof

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to Korean patent application 10-2016-0069055, filed on Jun. 2, 2017, incorporated herein by reference. 
     FIELD OF THE INVENTION 
     The present invention relates to a coated yarn, and more particularly, to a parti-colored yarn having multiple layers of urethane coating for imparting strength and multicolor to a yarn by exposing each color of each layer on the surface of the yarn, and a method of manufacturing same. 
     BACKGROUND OF THE INVENTION 
     Generally, an industrial yarn is produced by coating a thermoplastic resin such as PVC, PP, or thermoplastic polyurethane (TPU) on the surface of a polyester or nylon yarn using an extruder die in order to increase the strength of yarn. 
     However, it is hard to coating a small amount of coating resin, and, therefore, it is difficult to fabricate a coated yarn having a thickness of 1,000 denier or less. Otherwise, it is difficult to improve the durability and abrasion resistance of a coated yarn. 
     To solve such problem, Korean Patent No. 10-1318135 discloses a thermoplastic polyurethane compound composition for producing a coated yarn, which comprises thermoplastic polyurethane, a thickener and an olefin-based coupling agent. 
     Further, Korean Patent No. 10-1341055 entitled “A composition of thermoplastic polyurethane yarn and a method for producing same” describes a method for producing a multi-layered thermoplastic polyurethane yarn comprising the steps of mixing thermoplastic polyurethane, a thickener and a processing lubricant; melting and kneading the mixture; drying and aging to prepare a resin compound; and introducing the resin compound into a co-extruder to form a core yarn while introducing another resin selected from thermoplastic polyurethane, polyester, nylon and acryl into the co-extruder to form a shell layer. 
     However, although a coated yarn having a relatively thin coating layer can be produced by the above-mentioned methods, it is hard to realize a light weight since the density of the coated yarn is high. Further, it is difficult to implement a coated yarn having various colors, textures and functionalities, e.g., metallic feeling, thermochromic property, phosphorescent property, shifting colors, etc. 
     Hence, Korean Patent No. 10-1561890 filed and owned by the applicant provides an aqueous thermosetting urethane composition for coating yarns capable of realizing multi-layered yarn having a low density, i.e., light weight and improved physical properties including elasticity and textures. 
     DISCLOSURE OF INVENTION 
     Technical Problem 
     It is an object of the present invention to provide a multilayered multicolor yarn which can embody various colors in a single yarn. 
     It is another object of the present invention to provide a method for producing the multilayered multicolor yarn. 
     Solution to Problem 
     In a first aspect, the subject invention provides a multilayer coated multicolor yarn comprising a core yarn, a first coating layer formed on the core yarn and a second coating layer formed on the first coating layer, wherein at least a part of the first coating layer is not covered by the second coating layer so that each colors of the first and second coating layers appear at the surface of the multilayer coated multicolor yarn. 
     In another aspect, the multilayer coated multicolor yarn may further comprise a third coating layer formed on the second coating layer, wherein at least a part of the second coating layer is not covered by the third coating layer and at least a part of the first coating layer not covered by the second coating layer is not covered by the third coating layer so that each colors of the first, the second and third coating layers appear at the surface of the multilayer coated multicolor yarn. 
     In a further aspect, the multilayer coated multicolor yarn may further comprise an additional coating layer on the third coating layer, wherein each color of each coating layer appears at the surface of the multilayer coated multicolor yarn. 
     In an additional aspect, the multilayer coated multicolor yarn may be a twisted yarn twisted with a rotational speed of 1,000 to 10,000 rpm. 
     In an additional aspect, the multilayer coated multicolor yarn may by prepared by a method comprising the steps of coating a first resin composition including a first pigment on the surface of a core yarn and drying the first resin composition to form a first coating layer on the core yarn; coating a second resin composition including a second pigment on the first coating layer to form a second coating layer; removing a part of the second coating layer so that the first coating layer is partially exposed to the outside; and drying the second coating layer. 
     In an additional aspect, the method for preparing a multilayer coated multicolor yarn may further comprise the steps of coating a third resin composition including a third pigment after drying the second coating layer to form a third coating layer; removing a part of the third coating layer so that the first and second coating layers are partially exposed to the outside; and drying the third coating layer. 
     In an additional aspect, a part of the second coating layer or the third coating layer may be removed by scraping a part of the second or third coating layer before drying. 
     In an additional aspect, a part of the coating layer may be scraped by making a coated yarn discharging from an outlet of a coater contact with an edge of the outlet at a predetermined discharge angle by using a roller. 
     In an additional aspect, the roller may be an eccentric roller and the coated yarn contacts with the edge of the coater outlet at different points. 
     In an additional aspect, the roller may be mounted on a rotatable means which rotates at 360 degrees with respect to the center axis of the coater outlet so that the coated yarn discharge from the coater outlet may contact with the circumference of the outlet edge. 
     In an additional aspect, the method may further comprise twisting finally dried coated yarn to obtain twisted yarn. 
     Advantageous Effects of the Invention 
     The multilayer coated multicolor yarn according to the present invention is parti-colored, i.e., exposes various colors on the surface of the yarn, and, therefore, a fabric woven by the inventive yarn gives a unique aesthetic feeling. In addition, due to the multiple coating layers, the yarn has excellent abrasion resistance, mechanical properties, durability, thermoformability and adhesion property. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a schematic cross-sectional view of a two-layer coated multicolor yarn according to one embodiment of the present invention. 
         FIG. 2  is a schematic cross-sectional view of a three-layer coated multicolor yarn according to another embodiment of the present invention. 
         FIG. 3  is a schematic diagram of a process for fabricating a multi-layer coated multicolor yarn according to an embodiment of the present invention. 
         FIGS. 4A to 4C  are schematic diagrams of apparatus for fabricating a multilayer coated multicolor yarn according to various embodiments of the present invention. 
         FIGS. 5 and 6  are schematic side views of multilayer coated multicolor yarns fabricated according to various embodiments of the present invention. 
         FIG. 7  is a photograph showing the appearance of different multilayer coated multicolor yarns produced according to various embodiments of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. 
       FIG. 1  is a schematic cross-sectional view of a two-layer coated multicolor yarn according to one embodiment of the present invention. The two-layer coated multicolor yarn comprises a core yarn  1 , a first coating layer  10  formed on the core yarn  1 , and a second coating layer  20  formed on the first coating layer  10 . The color of the first coating layer  10  is exposed at a part  11  which is not covered by the second coating layer. 20 . 
       FIG. 2  shows a three-layer coated multicolor yarn according to another embodiment, which further comprises a third coating layer  30 . The three-layer coated multicolor yarn comprises a core yarn  1 , a first coating layer  10  and a second coating layer  20 , wherein at least a part  11  of the first coating layer  10  is not covered by the second coating layer  20  and the third coating layer  30 , and at least a part  21  of the second coating layer  20  is not covered by the third coating layer. Thereby, each color of the first, the second and the third coating layers can be observed at the surface of the coated yarn. 
     According to the present invention, it is possible to form a desired number of coating layer without limitation. That is, an additional layer can be formed on the third coating layer  30  such that each color of each layer can appears at the surface of the coated yarn. 
       FIG. 1  and  FIG. 2  are schematic cross-sectional views showing a simplified structure of a multi-layered multicolor yarn according to the present invention. In practice, each coating layer can be randomly exposed and covered. 
       FIG. 3  shows a manufacturing process of a multilayer coated multicolor yarn according to one embodiment of the present invention. The process comprises the steps of: 
     coating a first resin composition including a first pigment on the surface of a core yarn and drying the first resin composition to form a first coating layer on the core yarn; 
     coating a second resin composition including a second pigment on the first coating layer to form the second coating layer; 
     removing a part of the second coating layer so that the first coating layer is partially exposed to the outside (R); and 
     drying the second coating layer. 
       FIG. 3  shows an example of a two-layer coating as an example, but not limited thereto. In the case of a three-layer coating, the steps of forming a third coating layer after the second coating layer is dried, a removing a part of the third coating layer, and drying the third coating layer may be further performed. 
     That is, the method for preparing a three-layer coated multicolor yarn may further comprise the steps of coating a third resin composition including a third pigment after drying the second resin composition to form a third coating layer; removing a part of the third coating layer so that the first and second coating layers are partially exposed to the outside; and drying the third coating layer. 
     In the case of a multilayer coating having four or more layers, the process can be repeated with the same principle. 
     According to a preferred embodiment of the present invention, the step of removing (R) a part of a coating layer is performed by scraping off a part of the coating layer before drying. 
     In the process of scraping off a part of the coating layer, the coating process may be followed by a process of scraping off a part of the coating layer using a separate scraper. 
     Otherwise, as shown in  FIGS. 4A to 4C , the coated yarn discharging from a coater is brought into contact with an edge of the coater outlet at a predetermined angle by using a roller. 
     According to one embodiment, the roller  41   a  may be positioned at an angle to the coater outlet, as shown in  FIG. 4A , so that the coating layer of the coated yarn can be scratched by the edge of the coater outlet. 
     According to another embodiment, the roller  41   a  may be an eccentric roller  42   a , and the path of the coated yarn discharged from the coater outlet is changed so that the coated yarn discharged from the coater comes into contact with the edge of the coater outlet edge at different position. 
     According to another embodiment, a set of rollers  43   a ,  43   b ,  43   c  is installed into an apparatus  50  which is capable of rotating 360 degrees, thereby the coated yarn being contact with the entire circumference of the edge of the coater outlet. 
       FIG. 5  is a schematic side view of a two-layer coated yarn produced according to one embodiment. Scratches of the coating layer may appear spirally on the yarn surface.  FIG. 5  shows a two-layer coated yarn wherein the exposed portion  11  of the first coating layer is spirally uncovered by the second coating layer  20 . 
       FIG. 6  is a schematic side view of a three-layer coating, in which each colors of three layers are exposed by the part of second coating layer  21  spirally uncovered by the third coating layer  30  and the part of the first coating layer  11  spirally uncovered by both of the second and third coating layers. 
       FIGS. 5 and 6  assume that the spiral scratching occurs regularly to some extent. However, in practice, the spiral shape may be random, and the exposed part of the lower layer may be also irregular. 
     According to one embodiment of the present invention, if the finally formed coated yarn is twisted, the exposed part becomes denser, and more colorful and vivid color contrast can be obtained. In addition, the strength of the coated yarn greatly increases when twisted. 
     Thus, the process for fabricating the multilayer coating multicolor yarn according to the present invention may further comprise twisting the finally dried coated yarn. The multi-layer coated multicolor yarn may be twisted by rotating with a rotational speed of 1,000 to 10,000 rpm, preferably 2,000 to 5,000 rpm. 
     In the present invention, the conventional resin composition for coating the core yarn can be used without limitation as long as it is generally used for imparting color to a yarn in this field. For example, the resin composition is a urethane based resin composition. 
     In addition to the resin composition for imparting color, other additives can be additionally added to obtain various functions. For example, a water-based thermosetting urethane composition for yarn coating may comprise 100 parts by weight of an aqueous thermosetting urethane resin, 1.5 to 2.5 parts by weight of a thickener, 8 to 15 parts by weight of a pigment, and 2.5 to 3.5 parts by weight of a matting agent. 
     That is, an aqueous thermosetting urethane composition for coating a yarn according to the present invention is formed by mixing a predetermined amount of a thickener, a processing lubricant and a pigment with a water-based thermosetting urethane resin, and coating a core yarn such as polyester or nylon yarn with the aqueous thermosetting urethane composition in a desired number of layers, i.e., single or multi-layer. 
     Since the aqueous thermosetting urethane resin is water-based, there is no need for an organic solvent, and the desired viscosity can be easily controlled by adding a thickener while maintaining the required solid content. 
     In the present invention, the aqueous thermosetting urethane resin is selected from the group consisting of aqueous thermosetting silicone modified urethane, aqueous thermosetting polyurethane, aqueous thermosetting polyacryl urethane or a mixture thereof. The thickening agent is preferably polyacrylate. 
     A thickener is used to control the viscosity of the aqueous thermosetting urethane composition, and a predetermined amount of the thickener is added to obtain a desired thickness of the coating layer. 
     The thickener is preferably used in an amount of 1.5 to 2.5 parts by weight (PHR) based on 100 parts by weight of the aqueous thermosetting urethane resin. When the viscosity is higher than the above range, the resin composition may not be uniformly coated, and if it is lower than the above range, the viscosity may be too low to form an appropriate thickness of coating layer and the coating is not properly performed. 
     The processing lubricant may comprise a matting agent, a foam stabilizer, a dispersant, and a crosslinking agent. 
     The matting agent is preferably silica and may be added, preferably, in an amount of 2.5 to 3.5 parts by weight based on 100 parts by weight of the aqueous thermosetting urethane resin. 
     The matting agent is used for scattering incident or reflected light at the surface of the coated yarn. For example, amorphous inorganic silica having an average particle diameter of 20 μm or less can be used to provide a roughened surface to scatter incident light, thereby providing good surface gloss. 
     Thus, a water-based thermosetting urethane resin composition may be prepared by mixing an aqueous thermosetting urethane resin with an appropriate amount of a thickener and a processing lubricant. 
     In the present invention, a foam stabilizer, a dispersant, and a crosslinking agent which can be used to prepare the inventive yarn are not specially limited as long as they are generally used for fabricating a coated yarn. 
     As shown in  FIG. 3 , a first aqueous thermosetting urethane composition is supplied to the hopper and the core yarn is first coated with the aqueous thermosetting urethane composition, and then the coated yarn is discharged through a nozzle and then dried. Then, a second aqueous thermosetting urethane composition is coated on the coated yarn as the secondary coating, and a part of the second coating layer is removed by scraping, followed by drying, cooling, and winding to provide a multilayer coated multicolor yarn. 
       FIG. 7  is a photograph showing the appearances of various types of multilayer coated multicolor yarns produced according to the present invention. 
     In  FIG. 7 , (A) is an external view of a multicolor yarn having two coating layers according to one embodiment of the present invention; (B) is a multicolor yarn produced by twisting the yarn (A) with a rotational speed of about 3,000 rpm; and (C) is an external view of a multicolor yarn having three layers of coating. 
     As shown in  FIG. 7 , the multilayer coated multicolor yarn according to the present invention exposes various colors on the surface of the yarn, and, therefore, a fabric woven by the inventive yarn gives a unique aesthetic feeling. In addition, due to the multiple urethane coating layers, the yarn has excellent abrasion resistance, mechanical properties, durability, thermoformability and adhesion property.