DESC:TECHNICAL FIELD
[0001] The present disclosure relates, in general, to multilayer articles and nets made thereof, and more specifically, relates to a method of forming a high-strength, cut, wash and abrasion-resistant polymeric layer onto the textured coated structure and producing nettings out of the same.

BACKGROUND
[0002] Aquaculture cages are subject to a range of destructive forces prevalent in the open sea. Examples of such forces include strong ocean currents, sea waves, abrasion against metal components, pressure washing, and attacks from various sea animals, such as sea lions and dolphins. Any breakage in the cages due to these forces can potentially cause significant financial and ecological damage, as farmed fish could escape into the open environment. Therefore, it is imperative that aquaculture cages be sufficiently robust to withstand such deformational forces. To achieve this robustness, existing solutions employ different materials with distinct properties. For example, high-strength High-Density Polyethylene (HDPE) filaments are typically used to protect against static and dynamic loads, while polyester monofilaments are used to resist cuts from animal bites. However, these materials render the cages non-recyclable, which severely affects the ecological viability of such aquaculture cages.
[0003] Nettings used to make aquaculture cages consist of textured articles, such as twisted or braided twines. If the twines are made stiff or cut-resistant before the net-making step, twisting the twines to produce knots becomes extremely difficult. A shortcoming associated with the use of textured articles, such as nettings, to make aquaculture cages is that the interstices in these nettings are conducive to the growth of biofouling species, such as algae, barnacles, and mussels. This fouling growth reduces the size of the mesh openings in the nettings, which impedes proper water circulation in the cage. Reduced water circulation leads to a drastic reduction in dissolved oxygen levels in the cage's enclosure, resulting in stunted fish growth and potentially causing fish mortality in cases of severe fouling. Conventional solutions are known to address this deficiency by adding various anti-fouling additives and employing frequent pressure washing of the nettings. However, these existing techniques are not completely effective in preventing the reduction of water circulation in the cage enclosure. This is because the anti-fouling additives can only be incorporated in small concentrations in the filaments of the nettings, as adding these additives reduces the strength of the nettings. Furthermore, extrusion of filaments becomes more challenging when these anti-fouling additives are included in the polymer formulation of the nettings. Additionally, pressure washing at high pressures can lead to breakages in the nettings, resulting in the escape of fish from the cage. Deploying divers to perform the pressure washing also incurs a significant operational cost. Moreover, pressure washing typically fails to eliminate fouling, especially that which is present in the interstices between the filaments of the nettings. Growth of fouling species restarts at these interstices, causing the cage to clog again and necessitating frequent, costly cleaning operations.
[0004] Therefore, it is desired to overcome the drawbacks, shortcomings, and limitations associated with existing solutions, and develop a method to produce highly robust nettings that make the aquaculture cages. This method seeks to confer upon the aquaculture cages and associated twines the unique capability to exhibit flexibility conducive to knot formation before the net manufacturing stage, while concurrently imparting post-processing attributes such as stiffness, bite resistance, and cut-resistance to enhance overall durability and performance after the net is fabricated. The present invention also provide an interstice-free twine that can used to manufacture a netting with a surface that restricts growth of fouling species.

OBJECTS OF THE PRESENT DISCLOSURE
[0005] An object of the present disclosure relates, in general, to multilayer articles and nets made thereof, and more specifically, relates to a method of forming a high-strength, cut, wash and abrasion-resistant polymeric layer onto the textured coated structure and producing nettings out of the same.
[0006] Another object of the present disclosure provides a cross-linking process that results in a stiff polymeric layer on the surface of the netting, providing increased durability and resistance to wear and tear.
[0007] Another object of the present disclosure is to provide a mechanically recyclable knotted netting made from an interstice-free twine, that can be used to form aquaculture cages, while ensuring that the aquaculture cages possesses all the required properties for robustness while also being recyclable.
[0008] Another object of the present disclosure is to provide an interstice-free twine that can used to manufacture a netting with an outer surface that restricts growth of fouling species.
[0009] Another object of the present disclosure provide a method that facilitates easy knot formation, addressing challenges associated with stiff or cut-resistant materials.
[0010] Another object of the present disclosure provide a method that enhances bite and cut resistance, making the netting suitable for applications where resistance to external forces or impacts is crucial, such as aquaculture cages.
[0011] Yet another object of the present disclosure provides a method that ensures that aquaculture cages and twines possess the flexibility necessary for knot formation during the net manufacturing stage. This simplifies the fabrication process, allowing for efficient and secure knotting.

SUMMARY
[0012] Aspects of the present disclosure pertain to a mechanically recyclable knotted netting (also referred to as “netting” herein) made from an interstice-free twine, along with a method for manufacturing the same. The netting is produced through a process that forms a polymeric layer on the surface of a polymeric yarn structure, significantly enhancing its durability and wear resistance. This process addresses common challenges posed by stiff or cut-resistant materials by enabling easy knot formation. Additionally, the method of the present disclosure improves bite and cut resistance of the netting, making it particularly suitable for demanding applications, such as in aquaculture cages, where resistance to external forces is crucial. This combination of durability, flexibility, and resistance makes the netting highly effective for a variety of industrial applications.
[0013] In an aspect, the present disclosure provides a mechanically recyclable knotted netting constructed from an interstice-free twine. The twine includes an inner polymer yarn structure having a textured surface and made of a first material, and at least one outer layer made of polymer that has a melting point ranging from about +150 °C to -150 °C from the melting point of the first material.
[0014] According to an embodiment, the melting point of the polymer material of the at least one outer layer ranges from about +50 °C to -50 °C from the melting point of the first material.
[0015] According to an embodiment, the twine may include a functional additive added to the at least one outer layer. According to an embodiment, the functional additive may form at least 0.1% by weight of the at least one outer layer.
[0016] According to an embodiment, the functional additive may be selected from any or a combination of plastomer, Ultravoilet (UV) additive, elastomer, copper, Tralopyril silicone, a crosslinking agent, and an inorganic material.
[0017] According to an embodiment, the at least one outer layer may be added to the inner polymer yarn structure by melting at least one polymeric formulation through at least one extruder, and coating the inner polymer yarn structure with the at least one outer layer under pressure in a die.
[0018] According to an embodiment, the at least one polymeric formulation may include the polymer and the functional additive mixed in the at least one polymeric formulation.
[0019] According to an embodiment, the inner polymer yarn structure may be made of any or a combination of one or more fibers, filaments, or tapes that are twisted, combined, or arranged so as to form a continuous structure. The twisting, combining, or arrangement of the any or a combination of one or more fibers, filaments, or tapes may result in a texture being developed on surface of the inner polymer yarn structure.
[0020] According to an embodiment, each of the first material and the polymer may be made of any or a combination of a polyethylene, a polyamide, and a polyester but not limited to said polymers.
[0021] According to an embodiment, the polyethylene may be selected from but not limited to any or a combination of High Density Polyethylene (HDPE), Low Density Polyethene (LDPE), Linear Low-Density Polyethylene (LLDPE), Ultra-High Molecular Weight Polyethylene (UHMWPE), Medium-Density Polyethylene (MDPE), Cross-Linked Polyethylene (PEX), and thermoplastic elastomer (TPE). According to an embodiment, the polyamide may be selected from but not limited to any or a combination of Nylon6, Nylon66. According to an embodiment, the polyester may be selected from but not limited to any or a combination of Polyethylene Terephthalate (PET), and Polyethylene Terephthalate Glycol (PET-G), and Thermoplastic Polyester Elastomer (TPEE).
[0022] According to another aspect, the present disclosure pertains to a method of manufacturing a mechanically recyclable knotted netting constructed from an interstice-free twine. The method includes producing an inner polymer yarn structure having a textured surface and made of a first material. The method also includes passing the inner polymer yarn structure through a polymeric melt so as to form at least one outer layer made of a polymer on the inner polymer yarn structure, wherein the polymer has a melting point ranging from about +150 °C to -150 °C from the melting point of the first material.
[0023] According to an embodiment, the melting point of the polymer material of the at least one outer layer ranges from about +50 °C to -50 °C from the melting point of the first material.
[0024] According to an embodiment, the step of producing may include twisting, combining, or arranging any or a combination of one or more fibers, filaments, or tapes to form a continuous structure of the inner polymer yarn structure. The twisting, combining, or arrangement of the any or a combination of one or more fibers, filaments, or tapes results in a texture being developed on surface of the inner polymer yarn structure.
[0025] 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 THE DRAWINGS
[0026] 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.
[0027] FIG. 1 illustrates an exemplary view of a mechanically recyclable knotted netting made from an interstice-free twine, in accordance with an embodiment of the present disclosure.
[0028] FIG. 2 illustrates an exemplary flow chart representation of a method for manufacturing the mechanically recyclable knotted netting, in accordance with an embodiment of the present disclosure.
[0029] FIG. 3 shows an exemplary flow chart representation of a process of forming a stiff outer layer on surface of an inner polymer yarn structure, in accordance with an embodiment of the present disclosure.

DETAILED DESCRIPTION
[0030] The following is a detailed description of embodiments of the disclosure depicted in the accompanying drawings. The embodiments are in such detail as to clearly communicate the disclosure. If the specification states a component or feature “may”, “can”, “could”, or “might” be included or have a characteristic, that particular component or feature is not required to be included or have the characteristic.
[0031] As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
[0032] The description of terms and features related to the present disclosure shall be clear from the embodiments that are illustrated and described; however, the invention is not limited to these embodiments only. Numerous modifications, changes, variations, substitutions, and equivalents of the embodiments are possible within the scope of the present disclosure. Additionally, the invention can include other embodiments that are within the scope of the claims but are not described in detail with respect to the following description.
[0033] The present disclosure relates, in general, to multilayer articles and nets made thereof, and more specifically, relates to a method of forming a high-strength, cut, wash and abrasion-resistant polymeric layer onto textured coated articles and producing nettings out of the same.
[0034] The present disclosure provides a process for producing continuous textured structures, that are used to produce nettings and ropes. The process ensures that there is sufficient flexibility of the continuous structures before net or rope manufacturing for easy twisting or knotting and increased stiffness after moisture or heat processing of produced nets or ropes.
[0035] The present disclosure relates to a method for producing a netting structure that involves creating continuous textured structures. The textured structures traverse a polymeric melt that may contain cross-linkers, facilitating the binding of the polymeric melt onto the textured structures. The adherence of the polymeric melt to the surface of the textured structures during cooling establishes a connection between the polymer and the textured structures. Subsequently, a netting structure is fashioned through weaving, warp-knitting, or knotting the resulting coated structures together. The formed netting structure undergoes a stretching process crucial for achieving specific mesh dimensions and knots. The present disclosure can be described in enabling detail in the following examples, which may represent more than one embodiment of the present disclosure.
[0036] FIG. 1 illustrates an exemplary view of a mechanically recyclable knotted netting (also referred to as “netting” herein) 100 made from an interstice-free twine. The twine of the netting 100 includes an inner polymer yarn structure 102 having a textured surface and made of a first material. The twine also includes at least one outer layer 104 made of a polymer that has a melting point with a difference of not more than 150 °C from the melting point of the first material. In a preferred embodiment, the at least one outer layer 104 is made of a polymer that has a melting point with a difference of not more than 50 °C from the melting point of the first material. The twine may include a functional additive added to the at least one outer layer 104. The functional additive may form at least 0.1% by weight of the at least one outer layer 104. The functional additive may be selected from any or a combination of plastomer, Ultravoilet (UV) additive/absorber, elastomer, copper, Tralopyril silicone, a crosslinking agent, an inorganic material, or other additives.
[0037] The inner polymer yarn structure 102 may be made of any or a combination of one or more fibers, filaments, or tapes that are twisted, combined, or arranged so as to form a continuous structure. The twisting, combining, or arrangement of the any or a combination of one or more fibers, filaments, or tapes results in a texture being developed on surface of the inner polymer yarn structure 102.
[0038] Each of the first material of the inner polymer yarn structure 102 and the polymer of the at least one outer layer 104 may be made of any or a combination of a polyethylene, a polyamide, and a polyester. In an exemplary embodiment, the polyethylene may be selected from but not limited to any or a combination of High Density Polyethylene (HDPE), Low Density Polyethene (LDPE), Linear Low-Density Polyethylene (LLDPE), Ultra-High Molecular Weight Polyethylene (UHMWPE), Medium-Density Polyethylene (MDPE), Cross-Linked Polyethylene (PEX), thermoplastic elastomer (TPE), and the like. In an exemplary embodiment, the polyamide may be selected from but not limited to any or a combination of Nylon6, Nylon66. In an exemplary embodiment, the polyester may be selected from but not limited to any or a combination of Polyethylene Terephthalate (PET), and Polyethylene Terephthalate Glycol (PET-G), and Thermoplastic Polyester Elastomer (TPEE).
[0039] The at least one outer layer 104 may be added to the inner polymer yarn structure 102 by melting at least one polymeric formulation through at least one extruder, followed by coating the inner polymer yarn structure 102 with the at least one outer layer 104 under pressure in a die. The at least one polymeric formulation may include the polymer and the functional additive mixed in the polymeric formulation.
[0040] The netting 100 is made from the twine that is free from interstices. This netting is suitable for constructing aquaculture cages, ensuring that the cages retain essential qualities like durability and strength. It is designed to endure mechanical stresses from ocean currents, sea waves, and physical impacts from pressure washing or animal interactions. Additionally, the netting is recyclable, providing an eco-friendly option for disposal or repurposing once its useful life ends. This combination of durability and recyclability helps address the environmental issues associated with traditional aquaculture nettings, which are often non-recyclable due to the materials used in their fabrication. The interstice-free twine, is used to produce the netting 100, ensures that an outer surface of the netting 100 efficiently inhibits the growth of fouling organisms, such as algae, barnacles, and mussels. The interstice-free twine is designed to reduce or eliminate the gaps commonly found in conventional nettings, which create optimal conditions for fouling organisms to attach and grow. By removing these interstices, the netting effectively reduces the surface area available for fouling species, significantly preventing or delaying biofouling accumulation. As a result, the longevity of aquaculture cages is improved, the frequency of cleaning or pressure washing is reduced, and water circulation within the cage remains optimal. This ultimately enhances the health and growth of fishes formed using the aquaculture cages while lowering maintenance costs.
[0041] FIG. 2 shows an exemplary flow chart of a method 200 for manufacturing the netting 100 depicted in FIG. 1. The method 200 includes a step 202 of producing the inner polymer yarn structure 102 of the netting’s twine having the textured surface. The inner polymer yarn structure 102 is made of a first material. The method 200 also includes a step 204 of passing the inner polymer yarn structure 102 through a polymeric melt to form the at least one outer layer 104 made of a polymer on the inner polymer yarn structure 102. The polymer has a melting point with a difference of not more than 150 °C from the melting point of the first material. In a preferred embodiment, the at least one outer layer 104 is made of a polymer that has a melting point with a difference of not more than 50 °C from the melting point of the first material.
[0042] The step 202 of producing the inner polymer yarn structure 102 may include twisting, combining, or arranging any or a combination of one or more fibers, filaments, or tapes to form a continuous structure of the inner polymer yarn structure 102. The twisting, combining, or arrangement of the any or a combination of one or more fibers, filaments, or tapes results in a texture being developed on surface of the inner polymer yarn structure 102.
[0043] The method 200 facilitates formation of the at least one outer layer 104 as a protective layer over the textured surface of the inner polymer yarn structure 102, utilizing a cross-linking compound. The present disclosure encompasses a specific process for applying the cross-linking compound onto an inner polymer yarn structure 102, thereby enhancing the durability and protective attributes of the resulting twines and nettings.
[0044] In an exemplary embodiment, the method 200 for obtaining the cross-linked netting structure includes creating continuous textured structures, such as fibers, yarns, or twines, with a textured surface formed by the arrangement, twisting, or composition of the fibers yarns, or twines. The textured structures may be passed through a polymeric melt containing cross-linkers, with the polymeric melt binding onto the textured structures. The polymeric melt may be allowed to adhere to the surface of the inner polymer yarn structure 102 as it cools, forming a connection between the inner polymer yarn structure 102 made of the first material and the at least one outer layer 104 made of the polymer. A netting structure is formed by weaving, warp-knitting, or knotting the resulting coated structures together. The formed netting structure may be stretched to achieve specific mesh dimensions and knots, crucial for determining the final size and characteristics of the resulting nettings or twines. Further, the stretched netting structure may be subjected to heat or moisture, activating a cross-linking reaction in the polymer, resulting in the formation of at least one stiff polymeric outer layer 104 on the inner polymer yarn structure 102, thereby enhancing structural integrity and properties for intended applications.
[0045] In an exemplary embodiment, the inner polymer yarn structure 102 of the twine may include fibres that can be selected from any of natural, semi-synthetic and synthetic fibres, such as cellulosic fibres, regenerated protein fibres, acrylic fibres, polyolefin fibres, polyurethane fibres, vinyl fibres, blends and any combination thereof. The inner polymer yarn structure 102 can incorporate any or a combination of twisted and braided construction. Selection of fibres and type of construction may be based on strength, stiffness and thickness requirements.
[0046] The cross-linking compound can include a cross-linking agent incorporated into a polyethylene (PE)-based matrix. The cross-linking agent can be either peroxide, silane or azo compounds. The matrix for incorporating the cross-linking agents may be any PE-based polymers such as LDPE, LLDPE and HDPE or blends made thereof.
[0047] In an exemplary embodiment, the netting 100 formed by the method 200 provides improved bite or cut resistance, thereby protecting against attacks from a variety of predators in the sea. In another exemplary embodiment, the at least one outer layer 104 formed over the inner polymer yarn structure 102 provides improved abrasion resistance against different abrading surfaces such as well-boats, anchor fasteners, ropes, etc.
[0048] The at least one outer protective layer 104 may be capable of sustaining high-pressure cleaning of the netting 100, which may avoid fraying, breakage, fibrillation of yarns, thereby increasing life/longevity of the betting 100. The performance of the at least one outer protective layer 104 may be tested with the high-pressure cleaning, and may include pressure values of 100, 150, 200, 250 and 300 bar, without limitations. The equipment setup line for forming the at least one outer protective layer 104 on the twine can include an unwinding unit, a melt chamber and die, cooling system and a winding placed sequentially in the main line and an extruder arranged perpendicular to the main line and connected to the main at the melt chamber.
[0049] The method 200 may involve melting at least one polymeric formulation through an extruder, and coating the inner polymer yarn structure 102 with the at least one outer layer 104 under pressure in a die. The method 200 may also involve shaping and removing excess polymeric formulation through the die, cooling the coated twine, and finally, winding it up on a take-up unit. The process for forming the at least one outer protective layer 104 on the inner polymer yarn structure 102 is as follows:
Melt Formation and Conveyance:
[0050] The polymeric formulation may be melted in a screw extruder. The molten material may then be conveyed and pumped into a chamber, which serves as a melt reservoir.
Twine Coating Process:
[0051] The inner polymer yarn structure 102 to be coated may be unwound and directed through the melt reservoir. In this melt reservoir, the inner polymer yarn structure 102 gets covered by the melted composite formulation to form the at least one outer protective layer 104.
[0052] In an exemplary implementation, it may be appreciated by a person skilled in the art that the at least one outer protective layer 104 may include a single protective layer, or a multilayer protective coating.
Die and Excess Melt Removal:
[0053] The inner polymer yarn structure 102 coated with the at least one outer layer 104 may pass through a die located immediately after the melt reservoir. The die may include a hole with a specific diameter and shape, designed based on factors such as twine thickness, coating thickness needed, and the speed of the coating process. As the twine moves through the die hole, excess melted material is wiped off from the surface of the twine.
Cooling Station for Layer Formation:
[0054] After passing through the die, the inner polymer yarn structure 102 coated with the at least one outer layer 104 may enter a cooling station, which facilitates the formation of a uniform and durable outer layer 104 over the inner polymer yarn structure 102.
Take-Up Unit:
[0055] The coated twine comprising the inner polymer yarn structure 102 coated with the at least one outer layer 104 may then be wound up on the take-up unit, which collects the coated twine, completing the process of applying a uniform outer layer 104 through the described extrusion and coating method.
[0056] In a variant of the above process, the flow of the polymeric formulation can be divided into multiple streams downstream of the extruder's barrel. Using gear pumps, the melt can then be pumped through multiple reservoirs and dies, enabling the simultaneous coating of multiple twines.
[0057] The melting and conveying of the melt formulation as described in the above process can be carried out by a conventional single or twin-screw extruder that is placed perpendicular to the main line. Additionally, a plurality of extruders can also be arranged perpendicularly to the main line so that the layers with different formulations can be formed sequentially on the substrate twine.
[0058] The reservoir holding the melt formulation is equipped with heaters to maintain the melt at the desired temperature. The cooling station can be a forced air chamber, a quenching water bath, or the coated article can be cooled using natural air or a forced convection air chamber. In addition to die hole selection, the thickness of the formed layer can be controlled by adjusting the line speed of the process, which in turn depends on the size and running speed of the winder.
[0059] Further, the twines coated using above method can be used to produce nettings through various downstream processes. Once the nettings are produced, the cross-linking reaction may be carried out at elevated temperatures, with the aid of steam. The degree of cross-linking and, in turn, the properties of the outer protective layer 104 can be controlled by the temperature and time for which the crosslinking reaction takes place.
[0060] Thus, the present invention overcomes the drawbacks, shortcomings, and limitations associated with existing solutions, and provides a cross-linking process, culminating in the development of a robust outer polymeric layer 104 on the textured surface of the inner polymer yarn structure 102 to enhance durability and resist wear and tear. The method 200 not only streamlines the fabrication process by facilitating easy knot formation, overcoming challenges associated with rigid or cut-resistant materials, but also enhances bite and cut resistance, especially crucial for applications such as aquaculture cages where resilience to external forces is vital. Additionally, the nettings and twines formed by the method 200 ensure flexibility in aquaculture cages, while simplifying the process and enabling efficient and secure knotting.
[0061] The method 200, at step 202, includes producing the inner polymer yarn structure 102 of the twine having the textured surface. The inner polymer yarn structure 102 is made of a first material. The inner polymer yarn structure may be made of any or a combination of one or more fibers, filaments, or tapes that are twisted, combined, or arranged so as to form a continuous structure. The twisting, combining, or arrangement of the any or a combination of one or more fibers, filaments, or tapes results in a texture being developed on surface of the inner polymer yarn structure.
[0062] Thereafter, at step 204, the inner polymer yarn structure 102 is passed through the polymeric melt containing cross-linkers, with the polymeric melt binding onto outer surface of the inner polymer yarn structure 102. The polymeric melt contains cross-linkers, which are substances that promote the formation of cross-links or bonds between polymer chains.
[0063] Referring to FIG. 3, the step 204 of the method 200 may include, at step 302, allowing the polymeric melt to adhere to the surface of the inner polymer yarn structure 102 as it cools, forming a connection between the polymer material of the at least one outer layer 104 and the first material of the inner polymer yarn structure 102. As the textured structures of the inner polymer yarn structure 102 move through the polymeric melt, the melt adheres or binds onto the outer surface of the inner polymer yarn structure 102. This binding occurs as the polymeric melt cools, forming a connection between the polymer material of the at least one outer layer 104 and the first material of the inner polymer yarn structure 102.
[0064] The step 204 may include, at step 304, forming a netting structure by weaving, warp-knitting, or knotting the resulting coated structures together. The resulting inner polymer yarn structure 102 now coated with the at least one outer layer 104, can be woven, warp-knitted, or knotted together. In an exemplary implementation, it may be appreciated by a person skilled in the art that the coating of the at least one outer layer 104 can be a single layer coating or a multilayer coating. These techniques are employed to create a fabric or netting-like structure, where the coated yarns are intertwined to form a cohesive material.
[0065] The step 204 may include, at step 306, stretching the formed netting structure to obtain specific mesh dimensions and knots, crucial for determining the final size and characteristics. The formed nettings undergo a stretching process to achieve specific mesh dimensions and knots. This step is crucial for determining the final size and characteristics of the netting structure.
[0066] The step 204 may also include, at step 308, subjecting the stretched netting to heat or moisture, activating a cross-linking reaction in the polymer, resulting in the formation of a stiff outer polymeric layer 104 on the textured surface of the inner polymer yarn structure 102, thereby enhancing structural integrity and properties for intended applications. This activation step triggers the cross-linking reaction in the polymer, leading to the formation of the stiff outer polymeric layer 104 on the textured surface of the inner polymer yarn structure 102. This cross-linking enhances the structural integrity and properties of the inner polymer yarn structure 102, making it more robust and suitable for its intended applications.

EXAMPLES:
Example 1
[0067] A 1.5mm braided twine (inner polymer yarn structure 102) made of HDPE having a melting point of 135 °C was passed through a die of size 2.4mm. Ethylene Acrylic Acid with a melting point of 85 °C was pumped through the die using a first extruder while simultaneously extruding an LLDPE composite, containing 90wt% LLDPE and 0.5wt% cross-linker (dicumyl peroxide), with a melting point of 120 °C, through the die using a second extruder. On cooling, the LLDPE composite formed a coating layer (outer layer 104) over Ethylene Acrylic Acid, which in turn formed a coating layer over the HDPE braided twine. The coated twine was then weaved into a netting 100.
Example 2
[0068] A 3.8mm twisted twine (inner polymer yarn structure 102) made of Nylon-6 having a melting point of 220 °C was passed through a die of size 3.8 mm. Nylon-66 with a melting point of 85 °C was pumped through the die using an extruder. A UV stabilizer was added to the Nylon-66 formulation in a concentration of 0.6wt%. On cooling, the Nylon-66 formed a coating layer (outer layer 104) over the Nylon-6 twisted twine. The coated twine was finally weaved into a netting 100.
Example 3
[0069] A 2.2mm polyester braided twine (inner polymer yarn structure 102) made of Polyester having a melting point of 280 °C was passed through a die of size 2.8mm. PET-G elastomer with a melting point of 245 °C was pumped through the die using a first extruder. On cooling, the PET-G elastomer formed a coating layer (outer layer 104) over the polyester braided twine. The coated twine was then weaved into a netting 100.
[0070] Thus, the present disclosure provides a mechanically recyclable knotted netting with high-strength, cut-resistant, wash-resistant, and abrasion-resistant polymeric layers on textured coated structures, specifically designed for producing durable nettings, as well as a method for manufacturing the same. The method incorporates a cross-linking process that forms a stiff outer polymeric layer on the textured surfaces of the inner polymer yarn structure, enhancing its durability and wear resistance. It also improves bite and cut resistance, making the netting ideal for applications such as aquaculture cages, where resistance to external forces is crucial. Furthermore, the method ensures that the netting retains flexibility for knot formation during manufacturing, simplifying the fabrication process and enabling efficient and secure knotting.
[0071] It will be apparent to those skilled in the art that the method of the present disclosure may be provided using some or all of the mentioned features and components without departing from the scope of the present disclosure. While various embodiments of the present disclosure have been illustrated and described herein, it will be clear that the disclosure is not limited to these embodiments only. Numerous modifications, changes, variations, substitutions, and equivalents will be apparent to those skilled in the art, without departing from the spirit and scope of the disclosure, as described in the claims.

ADVANTAGES OF THE PRESENT INVENTION
[0072] The present invention provides a cross-linking process that results in a stiff polymeric layer on the surface of the netting, providing increased durability and resistance to wear and tear.
[0073] The present invention provides a method that facilitates easy knot formation, addressing challenges associated with stiff or cut-resistant materials.
[0074] The present invention provides a method that enhances bite and cut resistance, making the netting suitable for applications where resistance to external forces or impacts is crucial, such as aquaculture cages.
[0075] The present invention provides a mechanically recyclable knotted netting made from an interstice-free twine. This netting can be used to form aquaculture cages, while ensuring that the cages maintain all necessary properties for durability and robustness, such as the ability to withstand the mechanical forces from ocean currents, sea waves, and physical stress caused by pressure washing or animal interactions. The knotted netting also retains its recyclability, allowing for sustainable disposal or repurposing at the end of its useful life. The combination of mechanical strength and recyclability addresses the environmental concerns associated with conventional aquaculture nettings, which are often non-recyclable due to the materials used in their construction.
[0076] The present invention provides an interstice-free twine that can be used to manufacture a netting with an outer surface designed to restrict the growth of fouling species, such as algae, barnacles, and mussels. The twine is engineered to eliminate or minimize the presence of interstices or gaps that typically form in conventional nettings, which create ideal conditions for the attachment and proliferation of fouling organisms. By eliminating these interstices, the netting of the present invention reduces the available space for fouling species to latch onto, effectively preventing or significantly delaying the accumulation of biofouling. This improves the longevity of the aquaculture cage, reduces the need for frequent cleaning or pressure washing, and helps maintain optimal water circulation within the cage, ultimately improving the health and growth of farmed fish while reducing maintenance costs.
[0077] The present invention provides a method that ensures that aquaculture cages and twines possess the flexibility necessary for knot formation during the net manufacturing stage. This simplifies the fabrication process, allowing for efficient and secure knotting.
,CLAIMS:1. A mechanically recyclable knotted netting (100) constructed from an interstice-free twine, said twine comprising:
an inner polymer yarn structure (102) having a textured surface and made of a first material; and
at least one outer layer (104) made of polymer that has a melting point ranging from about +150 °C to -150 °C from the melting point of the first material.

2. The netting (100) as claimed in claim 1, wherein the melting point of the polymer of the at least one outer layer (104) ranges from about +50 °C to -50 °C from the melting point of the first material.

3. The netting (100) as claimed in claim 1, wherein the twine comprises a functional additive added to the at least one outer layer (104).

4. The netting (100) as claimed in claim 3, wherein the functional additive forms at least 0.1% by weight of the at least one outer layer (104).

5. The netting (100) as claimed in claim 3, wherein the functional additive is selected from any or a combination of plastomer, Ultravoilet (UV) additive, elastomer, copper, tralopyril silicone, a crosslinking agent, and an inorganic material.

6. The netting (100) as claimed in claim 1, wherein the at least one outer layer (104) is added to the inner polymer yarn structure (102) by melting at least one polymeric formulation through at least one extruder, and coating the inner polymer yarn structure (102) with the at least one outer layer (104) under pressure in a die.

7. The netting (100) as claimed in claim 6, wherein the at least one polymeric formulation comprises the polymer and the functional additive mixed in the at least one polymeric formulation.

8. The netting (100) as claimed in claim 1, wherein the inner polymer yarn structure (102) is made of any or a combination of one or more fibers, filaments, or tapes that are twisted, combined, or arranged so as to form a continuous structure, and wherein the twisting, combining, or arrangement of the any or a combination of one or more fibers, filaments, or tapes results in a texture being developed on surface of the inner polymer yarn structure (102).

9. The netting (100) as claimed in claim 1, wherein each of the first material and the polymer is made of any or a combination of a polyethylene, a polyamide, and a polyester.

10. The netting (100) as claimed in claim 9, wherein:
the polyethylene is selected from but not limited to any or a combination of High Density Polyethylene (HDPE), Low Density Polyethene (LDPE), Linear Low-Density Polyethylene (LLDPE), Ultra-High Molecular Weight Polyethylene (UHMWPE), Medium-Density Polyethylene (MDPE), Cross-Linked Polyethylene (PEX), and thermoplastic elastomer (TPE),
the polyamide is selected from but not limited to any or a combination of Nylon6, Nylon66, and
the polyester is selected from but not limited to any or a combination of Polyethylene Terephthalate (PET), and Polyethylene Terephthalate Glycol (PET-G), and Thermoplastic Polyester Elastomer (TPEE).

11. A method of manufacturing a mechanically recyclable knotted netting (100) constructed from an interstice-free twine, said method comprising the steps of:
producing an inner polymer yarn structure (102) having a textured surface and made of a first material;
passing the inner polymer yarn structure (102) through a polymeric melt so as to form at least one outer layer (104) made of a polymer on the inner polymer yarn structure (102), wherein the polymer has a melting point ranging from about +150 °C to -150 °C from the melting point of the first material.

12. The method as claimed in claim 11, wherein the melting point of the polymer of the at least one outer layer (104) ranges from about +50 °C to -50 °C from the melting point of the first material.

13. The method as claimed in claim 11, wherein the step of producing comprises twisting, combining, or arranging any or a combination of one or more fibers, filaments, or tapes to form a continuous structure of the inner polymer yarn structure (102), and wherein the twisting, combining, or arrangement of the any or a combination of one or more fibers, filaments, or tapes results in a texture being developed on surface of the inner polymer yarn structure (102).