DESC:FIELD OF INVENTION
[0001] The present invention, in general, relates to yarns. In particular, the present invention relates to a yarn with core-shell structure used in technical textile manufacturing used in aquaculture, fisheries, sports, geo-textiles textiles or other technical textile applications.

BACKGROUND
[0002] The following description of related art is intended to provide background information pertaining to the field of the disclosure. This section may include certain aspects of the art that may be related to various features of the present disclosure. However, it should be appreciated that this section be used only to enhance the understanding of the reader with respect to the present disclosure, and not as an admission of prior art.
[0003] Different types of fibres and yarns may be used in textiles owing to the high tensile strength. Some may be quite specific in composition and may relate to specific type of fibers and yarns. Any small change in fiber/yarn composition frequently may result in tremendous improvements in processing, as well as in end use of the yarn. There are various conventional methods developed to prepare such yarns.
[0004] In an example, polymer may be first dissolved in a volatile solvent. The solution may then be spun and cooled to form a gel filament, followed by stretching the filament and drying the desired yarn to manufacture the yarn. In another example, extrusion method may be used to produce high strength yarns. Such high strength yarns may be used to make technical textiles such as netting, ropes and fabric for applications such as fishing nets, aquaculture nets, sports nets, mooring ropes, agricultural shade nets, geo-textiles etc.
[0005] However, conventional and existing yarns may only provide strength, and the desired functionality is generally added in the form of a paint on the finished textile. More recently desired functionality has been achieved by adding additives during the extrusion process.
[0006] However there is a limitation, although additives provide functionality but they do not provide strength and in turn they act as an impurity and may result in drop in strength of the yarn depending on the loading percentage. Technology has been growing at a rapid pace and the need of the hour is high strength yarn with functionality to be able to solve industrial problems in a sustainable way. Currently there is no low cost method to develop a yarn with high strength with desired functionality.
[0007] Thus, there is a need in the art to develop a method of preparing yarn that effectively imparts improved properties to the yarn without compromising its strength to be used in nets for underwater application like aquaculture.

SUMMARY
[0008] Aspects of the present disclosure relates to yarns. In particular, the present invention relates to a yarn with core-shell structure used in technical textile manufacturing used in aquaculture, fisheries, sports, geo-textiles textiles or other technical textile applications.
[0009] An aspect of the present disclosure pertains to a system for preparing core-shell polymer yarn. The core-shell polymer yarn may include an inner core yarn having at least one of a polymer monofilament or a polymer multifilament. The core-shell polymer yarn may further include an outer shell of yarn having a mixture of at least one of a polymer with softening point below 160ºC, a biocide, an additive, or a combination thereof.
[0010] In another aspect, the at least one of the polymer monofilament or the polymer multifilament comprises group of one of a polyolefin’s, an amide, esters, or a combination thereof.
[0011] In yet another aspect, the polymer with softening point below 160ºC comprises one of a microcrystalline wax, an esterified rosin, hot melt resin, or a combination thereof.
[0012] In yet another aspect, the biocide comprises one of a metallic, a ceramic, an inorganic or an organic group.
[0013] In yet another aspect, the biocide is from a group comprising copper, cuprous oxide, cupric oxide, tralopyril, zinc pyrithione, copper pyrithione, silver, graphite, graphene, aluminium, boron, silver, carbon black, polyethylene glycol, Titanium dioxide, nano clay, barium sulphate, calcium carbonate, or metallic or ceramic or inorganic nano/micro fillers, or a combination thereof.
[0014] In yet another aspect, the additives may be of size less than 50 microns.
[0015] In yet another aspect, the additives may comprise one of a metallic, a ceramic, an inorganic, an organic group, or a combination thereof.
[0016] Another aspect of the present disclosure pertains to a method for preparing core-shell yarn. The method may include the steps of: quenching a yarn in a quenching bath to obtain a surface modified yarn, wherein the quenching bath contains an oxidising solution for surface modification of the yarn; pulling the surface modified yarn from the quenching bath over a first godet roller to obtain a pulled yarn; passing the pulled yarn in a hot water bath under a second godet roller, to soften the yarn to obtain a stretched yarn; passing the obtained stretched yarn through a treatment tank to obtain a core-shell yarn, wherein the treatment tank contains a shell forming formulation; cooling the obtained core-shell yarn at room temperature; and winding the cooled core-shell yarn on a winder.
[0017] In another aspect, the method may further include the steps of: melting a polymer by heating in an extrusion barrel to obtain a molten polymer; and extruding the molten polymer through a die to form a yarn.
[0018] In yet another aspect, the yarn may be a readymade yarn.
[0019] Various objects, features, aspects and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.

BRIEF DESCRIPTION OF DRAWINGS
[0020] The accompanying drawings are included to provide a further understanding of the present disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.
[0021] In the figures, similar components and/or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label with a second label that distinguishes among the similar components. If only the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label.
[0022] FIG. 1 illustrates an exemplary schematic representation of process flow for preparing core-shell yarn, in accordance with embodiments of the present disclosure; and
[0023] FIG. 2 illustrates an exemplary representation of core-shell yarn, in accordance with embodiments of the present disclosure.

DETAILED DESCRIPTION
[0024] In the following description, for the purposes of explanation, various specific details are set forth in order to provide a thorough understanding of embodiments of the present disclosure. It will be apparent, however, that embodiments of the present disclosure may be practiced without these specific details. Several features described hereafter can each be used independently of one another or with any combination of other features. An individual feature may not address all of the problems discussed above or might address only some of the problems discussed above. Some of the problems discussed above might not be fully addressed by any of the features described herein.
[0025] The ensuing description provides exemplary embodiments only, and is not intended to limit the scope, applicability, or configuration of the disclosure. Rather, the ensuing description of the exemplary embodiments will provide those skilled in the art with an enabling description for implementing an exemplary embodiment. It should be understood that various changes may be made in the function and arrangement of elements without departing from the spirit and scope of the invention as set forth.
[0026] Specific details are given in the following description to provide a thorough understanding of the embodiments. However, it will be understood by one of ordinary skill in the art that the embodiments may be practiced without these specific details. For example, circuits, systems, networks, processes, and other components may be shown as components in block diagram form in order not to obscure the embodiments in unnecessary detail. In other instances, well-known circuits, processes, algorithms, structures, and techniques may be shown without unnecessary detail in order to avoid obscuring the embodiments.
[0027] Also, it is noted that individual embodiments may be described as a process which is depicted as a flowchart, a flow diagram, a data flow diagram, a structure diagram, or a block diagram. Although a flowchart may describe the operations as a sequential process, many of the operations can be performed in parallel or concurrently. In addition, the order of the operations may be re-arranged. A process is terminated when its operations are completed but could have additional steps not included in a figure. A process may correspond to a method, a function, a procedure, a subroutine, a subprogram, etc. When a process corresponds to a function, its termination can correspond to a return of the function to the calling function or the main function.
[0028] The word “exemplary” and/or “demonstrative” is used herein to mean serving as an example, instance, or illustration. For the avoidance of doubt, the subject matter disclosed herein is not limited by such examples. In addition, any aspect or design described herein as “exemplary” and/or “demonstrative” is not necessarily to be construed as preferred or advantageous over other aspects or designs, nor is it meant to preclude equivalent exemplary structures and techniques known to those of ordinary skill in the art. Furthermore, to the extent that the terms “includes,” “has,” “contains,” and other similar words are used in either the detailed description or the claims, such terms are intended to be inclusive—in a manner similar to the term “comprising” as an open transition word—without precluding any additional or other elements.
[0029] Reference throughout this specification to “one embodiment” or “an embodiment” or “an instance” or “one instance” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.
[0030] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.
[0031] The present disclosure provides a method and system for preparing core-shell yarn. The core-shell yarn refers to a core of polymer yarn encapsulated or surrounded by a polymer shell with additives, wherein the core polymer provides the strength and the shell polymer with additives provides the functionality. The polymer yarn is passed through a quenching process to increase the surface energy of the yarn. In other words, the quenching process increases binding energy of the polymer yarn. Thus, the polymer shell with additives can easily form bonding with the core polymer yarn, when the polymer yarn is treated with a formulation contained in the treatment tank. In this manner, the core-shell structure of yarn is achieved.
[0032] FIG. 1 illustrates an exemplary schematic representation of process flow for preparing core-shell yarn, in accordance with embodiments of the present disclosure.
[0033] In method 100 for preparing the core-shell yarn, a yarn gets extruded by extrusion process according to step 101. The system performing the steps of method 100, in one example, may include an extrusion barrel that receives a polymer and converts the polymer into molten polymer by hearing it. In an embodiment, the extrusion barrel is divided into various zones for ease of temperature control in each zone requiring heating at different temperatures ranging from about 150ºC to 250ºC. In another embodiment, the extrusion barrel may include a hollow barrel chamber disposed horizontally with one or more screws to regulate the rate of intake of polymer yarn for the processing. In yet another embodiment, a readymade yarn may be used for quenching.
[0034] Continuing further, the system may include a die fitted at the distal end of the extrusion barrel for extruding the molten polymer to form a yarn. The die may include a plurality of apertures for extruding the molten polymer there from in the form of filaments to form yarn. Each aperture may be about 0.5 to 1.5 mm in diameter, preferably 1 mm in diameter. The number of apertures depends upon the number of yarns desired.
[0035] In an embodiment, the polymer may be selected from a group comprising hide high-density polyethylene (HDPE), polypropylene (PP), nylon, polyester, polyether ether ketone (PEEK), polyethylene terephthalate (PET), ultra-high molecular polyethylene polyester, aramid, carbon fibre, or etc.
[0036] Continuing further, the quenching process is initiated according to step 103 after the extrusion process. In this process, the molten polymer received as the output of the extrusion process, referred to as formed yarn may be passed through a quenching bath to obtain a surface modified yarn. The quenching bath may be filled with oxidizing solutions for surface modification of the yarn. By passing the molten polymer through the quenching tank, the surface energy of the polymer molten gets improved. In an embodiment, to avoid increase in temperature of oxidizing solution due to continuous addition of hot yarn in quenching bath, a circulation bath can be used to maintain the temperature of the oxidizing solution by circulating cooled oxidizing solution in quenching bath and cooling of hot oxidizing solution. The circulation bath is made up from hollow copper tubes, filled with circulating cooled water. These cooled copper tubes help to cool the hot oxidizing solution and the cooled oxidizing solution is resent to quenching bath.
[0037] Continuing further, according to step 105, the surface modified yarn may be pulled from the quenching bath and then passed through a hot water bath for the hot water treatment. In particular, the system may include a set of first godet rollers configured to pull the surface modified yarn from the quenching bath to pass over the first godet rollers. Thereafter, according to step 107, the yarn may then be treated with hot water treatment for softening the polymer yarn and allowing it to stretch out to achieve desired strength. In the process of hot water treatment, the pulled yarn may be passed through hot water contained in the hot water tank of the system. In an exemplary embodiment, the temperature range of the hot water tank may be above 90ºC.
[0038] In an embodiment, upon performing the hot water treatment, stretching tension can be maintained on the polymer yarn to achieve desired strength (step 5) according to step 109. In particular, the system may include a second godet roller configured to continuously pull the yarn from the hot water tank and stretch the yarn. In an exemplary embodiment, the first godet rollers are connected with the second godet rollers such that a pull mechanism at the second godet rollers continuously pulls the yarn from the first godet rollers through the hot water tank.
[0039] Continuing further, the obtained stretched yarn as a result of step 109 may be passed through a treatment tank according to step 111 to obtain a core-shell yarn. The treatment tank may contain the formulation containing any or a combination of a polymer with softening point below 160ºC, an esterified rosin with softening point below 160ºC, and a microcrystalline wax with softening point below 160ºC. In an embodiment, the formulation may also include a solvent selected from a group of perchloroethylene, alkanes (heptane, hexane, pentane), diethyl ether, the small alcohols (methanol, ethanol, isopropanol), xylene, and so on. In an embodiment, the formulation may also include at least one additive which may include any or a combination of metallic, ceramic, inorganic or organic group. In particular, additives can be selected from a group comprising but not limited to graphite, graphene, copper, cuprous oxide, cupric oxide, tralopyril, zinc pyrithione, copper pyrithione, aluminium, boron, silver, carbon, polyethylene glycol, Titanium dioxide, nano clay, barium sulphate, calcium carbonate or metallic or ceramic or inorganic nano/micro fillers. In an embodiment, the particle size of additives may be less than 50 microns in size.
[0040] The treatment tank embedded with hot steam based heated system helps to melt down the hot melt, esterified rosin, and microcrystalline wax contained in the formulation. The temperature in the treatment tank may be ranging from 80ºC to 160ºC. In an embodiment, the additives may be uniformly mixed with air bubblers which are installed in the treatment tank.
[0041] In an embodiment, the treated yarn as a result of step 111, may get cooled at room temperature and pulled through a yarn puller roller from the treatment tank, where the yarn puller roller helps to separate and maintain the tension on yarn and goes towards the winder according to step 113. The winder winds the yarn on the cops or tubes according to step 115.
[0042] FIG. 2 illustrates an exemplary representation of core-shell yarn, in accordance with embodiments of the present disclosure. The yarn 200 may include an inner core 201 formed by the polymer yarn and an outer shell 202 formed with polymer and additives.
[0043] The present disclosure provides a method and system for preparing core-shell yarn with the self-curing ultra-bonded composition. The polymer yarn is passed through a quenching process that increases the surface energy of the yarn. The polymer yarn is then passed through a treatment tank containing a specific formulation containing additives. As a result, the additives can easily form bonding with the polymer yarn at the outer surface of the yarn forming the shell of core-shell yarn. In this manner, the core-shell structure of yarn is achieved.
[0044] It would be appreciated that the method of preparing core-shell herein explained herein includes a set of pre-processing steps such as extrusion, quenching, hot water treatment before passing through the treatment tank, however, the proposed core-shell yarn can be prepared with one or more alternative steps before passing through the treatment tank.
[0045] While considerable emphasis has been placed herein on the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the invention. These and other changes in the preferred embodiments of the invention will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter to be implemented merely as illustrative of the invention and not as limitation. ,CLAIMS:1. A system for preparing a core-shell polymer yarn (200), the system comprising:
an inner core yarn (201) having at least one of a polymer monofilament or a polymer multifilament; and
an outer shell (202) of yarn having a mixture of at least one of a polymer with softening point below 160ºC, a biocide, an additive, or a combination thereof.

2. The system as claimed in claim 1, wherein the at least one of the polymer monofilament or the polymer multifilament comprises group of one of a polyolefin’s, an amide, esters, or a combination thereof.

3. The system as claimed in claim 1, wherein the polymer with softening point below 160ºC comprises one of a microcrystalline wax, an esterified rosin, hot melt resin, or a combination thereof.

4. The system as claimed in claim 1, wherein the biocide comprises one of a metallic, a ceramic, an inorganic or an organic group.

5. The system as claimed in claim 1, wherein the biocide is from a group comprising copper, cuprous oxide, cupric oxide, tralopyril, zinc pyrithione, copper pyrithione, silver, graphite, graphene, aluminium, boron, silver, carbon black, polyethylene glycol, Titanium dioxide, nano clay, barium sulphate, calcium carbonate, or metallic or ceramic or inorganic nano/micro fillers, or a combination thereof.

6. The system as claimed in claim 1, wherein the additives may be of size less than 50 microns.

7. The system as claimed in claim 1, wherein the additives may comprise one of a metallic, a ceramic, an inorganic, an organic group, or a combination thereof.

8. A method (100) of preparing a core-shell yarn, the method comprising:
quenching a yarn in a quenching bath to obtain a surface modified yarn, wherein the quenching bath contains an oxidising solution for surface modification of the yarn;
pulling the surface modified yarn from the quenching bath over a first godet roller to obtain a pulled yarn;
passing the pulled yarn in a hot water bath under a second godet roller, to soften the yarn to obtain a stretched yarn;
passing the obtained stretched yarn through a treatment tank to obtain a core-shell yarn, wherein the treatment tank contains a shell forming formulation;
cooling the obtained core-shell yarn at room temperature; and
winding the cooled core-shell yarn on a winder.

9. The method as claimed in claim 8, wherein the method (100) further comprising:
melting a polymer by heating in an extrusion barrel to obtain a molten polymer; and
extruding the molten polymer through a die to form a yarn.

10. The method as claimed in claim 8, wherein the yarn is a readymade yarn.