A metal core coated with a plastic lining having copper oxide nanoparticles

Abstract

The present invention relates to a core intended for manufacturing a net for culturing fish, which is coated with a plastic lining or coating, and for fixing or securing a cable. The core slows down the fouling rate by freshwater and marine biological substances, and the plastic coating contains copper oxide nanoparticles dispersed throughout the plastic matrix, having a size between 50 and 200 nanometers (nm) and a concentration of 10 to 30% by weight. The copper oxide nanoparticles can aggregate to form aggregates having a size between 500 and 1000 nm. The copper oxide nanoparticles are oxidized to the Cu +2 state.

Description

Technical Field

[0001] The present invention relates to a metal core coated with a plastic lining or coating having copper oxide nanoparticles disposed therein, for the purpose of reducing the fouling rate of visible organisms and microorganisms in the ocean and fresh water. More specifically, the present invention is a metal core coated with a plastic having copper oxide nanoparticles that act as an antifouling agent to extend its service life, wherein the core is a metal wire, a metal cable composed of a single strand composed of a plurality of wires, or a cable composed of a plurality of strands.

Background Art

[0002] In the ocean, fisheries, aquaculture, and aquaculture industries, especially marine structures such as aquaculture cages, oil platforms, and towers supporting wind turbines, have elements exposed to water, and visible organisms and microorganisms in the ocean deposit on the outer surface, so regular cleaning or replacement is necessary.

[0003] In many of these applications, the structure is fixed to the seabed by cables that suffer from fouling problems.

[0004] On the inside, this type of structure is, for example, especially the tower of an oil platform and a wind turbine support. Also, a cage raft for the cultivation of aquaculture species must be fixed to the seabed or to the rocks of the seabed bank of an aquaculture center, and thus is exposed to the problem of fouling by aquaculture biological substances.

[0005] Specifically, in the fish farming industry, a fish farming cage is formed by a floating structure having a net made of metal wire at its periphery and in the water, and forms a confinement of a certain amount of water for the purpose of containing fish in the growth process.

[0006] The fact that the wire mesh is located underwater causes marine biological substances (hydrobiological organisms) to become embedded over time, increasing the weight of the mesh and thus the mechanical stress. Additionally, the mesh openings close, hindering the water circulation that affects the fish during cultivation.

[0007] To overcome this problem, the nets are cleaned every 15 days in summer and every two months in winter. This means that divers equipped with pressure washers have to dive in to clean them on-site, which increases the cost of operating each cage raft. The nets are also removed and cleaned at the net factory.

[0008] Cleaning can also be done using a robotic cleaning system based on a rotating disk that emits high-pressure water jets from its nozzles. However, this also affects the operating cost of the fish cages.

[0009] There are nets with an antifouling paint layer, but due to the effect of removing this layer, it causes chemical pollution in the water, so they cannot be cleaned on-site (in accordance with Chilean regulations). Therefore, they should only be cleaned in factories that include water treatment plants (waste and effluents). For this reason, the nets with antifouling paint are removed and replaced approximately every four months in summer and every six months in winter. This frequency can (usually) vary depending on the level of fouling aggressiveness.

[0010] Fouling materials are initially generally formed as precursors by a biofilm composed of bacteria, microalgae, and microorganisms, and then major fouling organisms such as mollusks (e.g., mussels), crustaceans (e.g., picoroco), tunicates (e.g., piures type), macroalgae, hydrozoans, and spores of mollusks attach to substrates (e.g., plastic, HDPE, wood, the hull of a boat, the floats in a salmon pond, or plastic flotation pipes, etc.) and begin to grow, resulting in actual fouling (macro-fouling).

[0011] To prevent the floating cage raft of the structure from moving, an anchor cable, which also has the problem of fouling, is used, and the service life is significantly reduced.

[0012] Therefore, a first object of the present invention is to provide a metal core including a plastic lining or coating containing copper oxide nanoparticles therein, wherein the core is a metal wire used for manufacturing a net for a raft and a cage for fish farming, which reduces (antifouling) the fouling rate of marine visible organisms and microorganisms so as to extend the service life and shorten the net replacement period.

[0013] A second object of the present invention is to provide a metal core including a plastic lining or coating containing copper oxide nanoparticles therein, wherein the core is a metal cable composed of a single strand formed in sequence by a plurality of metal wires or a metal cable composed of a plurality of strands, which is used for fixing a marine structure, reduces (antifouling) the fouling rate of marine visible organisms and microorganisms, thereby extending the service life and shortening the cable replacement period.

[0014] A third object of the present invention is to provide a mesh for a cage raft for fish farming, which is composed of metal wires having a plastic lining or coating with copper oxide nanoparticles, and the plastic lining having the copper nanoparticles has sufficient resistance so that the plastic is not damaged or broken during the extrusion process performed with the metal wire and during the folding of the metal wire strands having a plastic coating for forming the weaving of the net.

[0015] One possible solution to this type of problem is to use copper, as it is widely known in the state of the art that copper has biocidal properties and is thus used in a number of applications. Among these applications, it is used as nanoparticles and added to various materials including plastics to transfer this property. However, when the object to be coated is in water, this property is rapidly lost, so it is necessary to find an alternative to extend the service life of elements coated with this plastic.

[0016] On the other hand, in the state of the art, attempts have been made to solve the fouling problem using nanoparticles of various metals containing copper. For example, Chinese Patent No. 111926407 discloses a method for processing nano-sized antifouling copper-nickel plastic filaments containing grafted polyguanidine salts. This method includes three processes: raw material compounding, melt spinning and stretching, and heat forming. Furthermore, using high-density grafted polyguanidine salt particles / polyethylene polyethylene particles and surface-modified copper-nickel alloy nanoparticles as the main raw materials, a composite material with a synergistic antifouling effect is first obtained, and then a synergistic antifouling plastic filament is obtained after the wire drawing technique. The synergistic antifouling filament performs a synergistic antifouling treatment against algae and other fouling organisms. The plastic filament thus obtained prevents fouling organisms from adhering to the surface of fish farming facilities and growing inside the nets. This document indeed discloses a method for processing plastic filaments having nano-sized copper and nickel nanoparticles containing grafted polyguanidine salts to obtain plastic filaments having antifouling properties, but does not specifically disclose a metal wire having a plastic coating or lining containing only copper oxide nanoparticles. The fouling rate of biological substances in the ocean and fresh water is also not disclosed.

[0017] On the one hand, U.S. Patent No. 4,603,653 discloses a marine antifouling material for providing an antifouling surface for use in seawater. This antifouling surface is inert to water, insoluble in water, flexible, and extensible, has an outer surface and an opposite inner surface, and includes a layer of an elastomeric carrier material in which a single layer of a plurality of copper or copper alloy particles is embedded. All of the particles are essentially the same size within the range of 0.5 to 3.0 millimeters, the ratio of the major dimensions of the particles is all within the range of about 0.7 to 1.0, the single layer has a maximum thickness equal to the size of the particles, and all of the particles are exposed on the outer surface of the carrier material, providing a number of discrete copper regions of substantially uniform size on the outer surface of the inert material continuum. The regions are spaced between 0.5 and 0.75 millimeters apart, and the total area of the spaced copper regions is between 20% and 40% of the total area of the antifouling surface of the antifouling material. The particle layer is spaced from the inner surface on the opposite side of the carrier material, so there is no exposed copper on the inside of the surface. The antifouling surface of the antifouling material is accessible to seawater, and the number of spaced copper regions therein delays or prevents the growth of marine organisms on the antifouling surface. The exposed surface having the copper particles of this material can be provided by embedding it in a support material such as a woven or knitted wire mesh or an expanded metal grid. It is true that this document discloses a material having a layer of copper particles, and the material can be applied to metal products such as mesh wires. However, it is not disclosed that this material contains only copper oxide nanoparticles as the sole antifouling element, that the nanoparticles are uniformly dispersed in the polymer matrix, and how slow the fouling rate of biological substances in the ocean and fresh water is. Similarly, this document discloses a material having copper particles in the range of 0.5 to 3 millimeters, which is far from nanotechnology.

[0018] Chilean Patent No. 202100106 describes copper nanoparticles, nanopolymers containing them, disinfectant compositions, and surface-protective antibacterial adhesive films / films containing them (including such non-rigid surfaces, fabrics, plastic films, nets, etc. with antifouling properties). This film can also be included in hard surfaces for daily or public use such as countertops, handrails, handles, toilets, urinals, etc. This document describes, among other things, that nanoparticles can be incorporated into plastic and net films, but there is no specific disclosure of metal wires coated with copper oxide nanoparticles acting as an anti-fouling element, and there is little mention of the fouling rate of marine and freshwater biological substances. None of the prior art documents disclose a core metal wire or cable with a plastic lining or coating, and the plastic has only copper oxide nanoparticles, providing a much simpler solution than the prior art to reduce the fouling rate of marine and freshwater biological substances, thereby extending the service life and providing a metal wire or cable with antifouling properties.

Summary of the Invention

[0019] The present invention relates to a metal core coated with a plastic lining or coating having copper oxide nanoparticles disposed therein, for the purpose of reducing the fouling rate of visible organisms and microorganisms in marine and freshwater. More specifically, the present invention is a core coated with a plastic having copper oxide nanoparticles acting as an anti-fouling agent to extend its service life, and the core is a wire, a cable composed of a single strand composed of a plurality of wires, or a cable composed of a plurality of strands.

[0020] The copper nanoparticles used in the present invention are mainly obtained by elemental copper or metallic copper nanoparticles in the oxidation state 0. These nanoparticles are treated to accelerate their oxidation and keep them in the copper +2 (Cu +2 ) state (hereinafter, copper oxide nanoparticles).

[0021] Copper oxide nanoparticles are dispersed in the coated plastic, have a size of 50 to 200 nanometers (nm), and are in a proportion between 10 and 30% by weight within the polymer matrix. Typically, these copper oxide nanoparticles have an elliptical, spherical or amorphous shape.

[0022] In the manufacturing process, the copper oxide nanoparticles have a size between 50 and 200 nm, and they are mixed with a hot plastic material to form a material that is applied onto a zinc-plated wire in order to have uniformly dispersed particles along the coating. When the nanoparticles enter the polymer matrix, as shown in the photograph of Figure 1, some of them group together to form aggregates that reach a size between 500 and 1000 nm. The plastic used is preferably high-density polyethylene (HDPE), medium-density polyethylene (MDPE), low-density polyethylene (LDPE), polyvinyl chloride or PVC. The copper nanoparticles are dispersed in the plastic at a concentration between 10 and 30% by weight.

[0023] The plastic having copper oxide nanoparticles is injected into a hopper that feeds an extruder to hot-extrusion mold the plastic onto a zinc-plated wire, thus forming a uniform coating on said wire. The zinc-plated wire passing through the extruder has a diameter between 0.5 and 10 millimeters, and the plastic coating by the copper oxide nanoparticles has a thickness between 0.5 and 1.0 millimeters. The wire used for the manufacture of the net has a final diameter of a plasticized wire between 1.5 and 12 millimeters.

Brief Description of the Drawings

[0024]

Figure 1

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Figure 10

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Figure 12

Figure 13

Figure 14

DETAILED DESCRIPTION OF THE INVENTION

[0025] The present invention relates to a metal core coated with a plastic lining or coating having copper oxide nanoparticles disposed therein, for the purpose of reducing the fouling rate of visible organisms and microorganisms in the ocean and fresh water. More specifically, the present invention is a metal core coated with a plastic having copper oxide nanoparticles that act as an antifouling agent to extend its storage life, wherein the core is a metal wire, a metal cable composed of a single strand composed of a plurality of wires, or a cable composed of a plurality of strands.

[0026] As described above, it is known to apply copper nanoparticles to a plastic material in order to impart the biocidal properties of copper to the plastic material. Similarly, plastics having copper nanoparticles are used to obtain fish farming nets or fishing nets having antifouling properties. However, neither mentions the type of copper nanoparticles used, nor mentions the growth rate of biological substances in the ocean or fresh water or the application to wires or metal cables.

[0027] Biological substances that adhere to the surface of any material in water are generally formed from precursors that are biofilms composed of bacteria, microalgae and microorganisms. Subsequently, primary fouling organisms such as algal spores, molluscs and crustacean larvae, especially molluscs, crustaceans and barnacles, adhere. Therefore, when the microorganisms are eliminated, the formation of algae, molluscs and crustaceans occurs. For this reason, knowing that copper is a biocidal metal, it is very advantageous to investigate its behavior in its various forms.

[0028] For the purpose of coating a metal wire or cable with a plastic coating in the present invention, copper must be dispersed in the polymer matrix. For this purpose, plastic materials having copper micro and nanoparticles were investigated.

[0029] For this purpose, laboratory tests were conducted using test tubes in the form of high-density polyethylene (HDPE) plates to which both copper microparticles and copper nanoparticles were added.

[0030] The copper nanoparticles used in the present invention are initially obtained by elemental copper nanoparticles or metallic copper in the oxidation state 0. These nanoparticles are processed to accelerate their oxidation and keep them in the Cu +2 state (hereinafter, copper oxide nanoparticles). This oxidation enables the nanoparticles to be more aggressive towards microorganisms and act much faster on them.

[0031] The first group of plates is formed of HDPE containing elemental or metallic copper nanoparticles, the second group of plates is formed of HDPE containing copper oxide nanoparticles, the third group of plates is formed of HDPE containing polyamide with 10% of a copper microparticle-based compound, and the fourth group of plates is formed of HDPE containing polyamide with 30% of a copper microparticle-based compound.

[0032] The size of the copper nanoparticles in the first two groups of plates was between 50 and 200 nm, and the concentration of the nanoparticles in the HDPE was 10% - 20 wt%. As shown in the photograph of Figure 1, there are some nanoparticles that group together to form aggregates reaching sizes between 500 and 1000 nm.

[0033] Laboratory tests To conduct the laboratory tests, an evaluation methodology based on ISO 22196:2011 "Measurement of antibacterial activity on plastics and other non-porous surfaces" (Testing of antibacterial activity on plastics and other non-porous surfaces) was applied to bacteria widely distributed in the marine environment, and two strains of bacteria isolated from the marine environment of Chile (Tenacibaculum dicentrarchi (T. dicetrarchi) and Vibrio sp.) were tested with reference to Escherichia coli (E. coli) ATCC 25922 strain.

[0034] Escherichia coli (E.Coli) bacteria were grown on trypticase soy (TSA) solid medium, and T. dicentrarchi bacteria and Vibrio bacteria were grown on marine agar (MA).

[0035] As shown in Table 1 below, each bacterium or pathogen was evaluated in an independent test for each material being tested.

Table 1

[0036] Plates prepared for tests including a control without microparticles and nanoparticles had a size of 50×50 mm and a thickness of less than 10 mm. In each assay, as shown in Figure 2, the plates were placed in sterile Petri dishes, and the bacterial inoculation material was prepared in their respective broths (tryptone soy broth - soybean broth for Escherichia coli (E.Coli) bacteria and marine broth for T. dicentrarchi and Vibrio bacteria), and 400 pL of it was added to the surface of each plate. The amount was spread with a plastic loop, covered with a 40×40 mm film piece, and pressed to cover the entire surface of each plate. Each Petri dish was closed, and then immediately the bacterial recovery was advanced and measured at the initial time (T0). Subsequently, this was incubated at 35°C for Escherichia coli (E.Coli) and at 18°C for T. dicentrarchi and Vibrio sp. for 24 hours (T24).

[0037] For bacterial recovery, the film and test pieces were washed with 8 mL of TSB recovery broth and marine broth containing 0.7% Tween 80, taking care to wash the entire test piece repeatedly. Subsequently, viable cell counting was performed, 100 pL of the medium containing the recovered bacteria was collected, and a 10-fold serial dilution was made. Each dilution was plated in triplicate (repeated test) on tryptone soy agar (TSA) plates and marine environment (AM) plates according to the bacterial species as shown above.

[0038] ISO 22196:2011 determines the activity of an antibacterial active surface by quantifying bacterial cells in contact with the plastic surface and bacterial cells recovered after 24 hours at 35°C. The antibacterial effect is determined by comparing the survival of bacteria on surfaces treated with antibacterial agents (copper micro- and nanoparticles) with that on another untreated surface or a control sample.

[0039] The calculation of the results was carried out in accordance with the provisions of the ISO 22196:2011 standard, and in each case, the antibacterial activity (R) was determined based on the viable count (N) according to the following formula (I): N = (100 × C × D × V) / A (I) Where: N = the number of viable bacteria recovered per 1 cm 2 of the test piece evaluated. C = the average plate count of the replicate tests D = the dilution factor of the plate. V = the volume (mL) of the culture broth added in the test A = the surface (mm 2 ) of the polyethylene film used in the test to coat the test piece

[0040] The results for each bacterium are shown in Tables 2 to 4. As follows:

Table 2-1

Table 2-2

Table 3-1

Table 3-2

Table 4-1

Table 4-2

[0041] In this way, the antibacterial activity value or antibacterial activity value was calculated from the logarithmic values of the viable cell counts (N) at T0 and T24.

[0042] R follows the following formula II shown in the standard. R = (Ut - U0) - (At - U0) = (Ut - At) (II) In the formula, R = antibacterial activity U0 = cm recovered from the control sample immediately after inoculation 2 It is the average of the decimal logarithm of the viable cell count in the cell. Ut = cm recovered from the control of the inventors after 24 hours 2 It is the average of the decimal logarithm of the viable cell count in the cell. At = cm recovered from the sample after 24 hours 2 It is the average of the decimal logarithm of the viable cell count in the cell.

[0043] The higher the R value, the higher the antibacterial activity of the material is evaluated. The results are shown in Table 5 below:

Table 5

[0044] These results show that the antibacterial resistance of the control plastic plate (without copper microparticles and nanoparticles) has zero effectiveness, and that the plastic plate containing copper oxide nanoparticles (M2) has the best antibacterial effectiveness.

[0045] This can be seen in FIGS. 3, 4 and 5, where bacterial crops corresponding to various papers in which the counting for determining the value of R is performed are shown.

[0046] In the case of FIG. 3, the control plate, M1, PAG-10 and PAG-30 have a significant increase in bacteria in Escherichia coli (E. coli) bacteria at 24 hours (T24), but the increase in the M2 plate is very small.

[0047] In the case of Figure 4, the control plates show a significant increase in the bacterium Tenacibaculum dicentrarchi (T. dicentrarchi) compared to plates M1, PAG-10, and PAG-30. However, the growth of bacteria (T. dicentrarchi) on the M2 control plate is very slight compared to the control plates, similar to that on the M1, PAG-10, and PAG-30 plates.

[0048] Finally, in the case of Figure 5, the control plate and the M1 plate at 24 hours (T24) show approximately twice the growth compared to the start of the test (T0). Moderate effects are observed on the PAG-10 and PAG-30 plates. The M2 plate shows virtually no growth.

[0049] Based on the above, it can be stated that the plastic containing copper oxide nanoparticles is the material with the best biocidal effect compared to the materials tested.

[0050] In addition to laboratory tests, field tests were conducted to visualize the antifouling effect of plastic materials using copper nanoparticles.

[0051] Field test In the field test conducted, materials containing elemental or metallic copper nanoparticles and copper oxide nanoparticles, namely materials M1 and M2, were considered.

[0052] The in-situ test consisted of immersing two groups of plastic plates in the sea. As control materials, a first group of plastic plates consisting of an HDPE plate without copper nanoparticles, an HDPE plate (referred to as S1) containing nanoparticles of elemental or metallic copper (referred to as M1) with a smooth surface, and an HDPE plate (referred to as S2) containing nanoparticles of elemental or metallic copper (M1) with a rough surface, and; a second group of plastic plates consisting of an HDPE plate without copper nanoparticles as a control material, an HDPE plate containing copper oxide nanoparticles (referred to as M2) with a smooth surface (S1), and an HDPE plate containing copper oxide nanoparticles (M2) with a rough surface (S2). In these in-situ tests, the plates were immersed in the sea, taken out after 20 days, and the evolution of the deposited biological substances was observed and photographed to record such evolution. Thereafter, the plates were immersed again. This operation was repeated on the 48th, 63rd, 73rd and 97th days.

[0053] The first group of plates is shown in Figure 6, which shows the evolution of the biological substances embedded in the plates as time progresses.

[0054] As can be observed on the 20th day of submersion, the control plate, the M1 plate with S1 surface and the M1 plate with S2 surface are completely free of biological substances.

[0055] On the 48th day, the control and the M1 plate with S2 surface are completely covered with a thin layer of biological substances, while the M1 plate with S1 surface begins to show a small amount of deposited biological substances.

[0056] On the 63rd day, the control plate as well as the M1 with S2 surface and the M1 with S1 surface are completely covered with the deposited biological substances. It can be seen that the amount of biological substances on the plate M1 with surface S1 is less than that on the plate M1 with surface S2.

[0057] On the 73rd and 97th days, the control plate, plate M1 with S1 surface, and plate M1 with S2 surface were completely covered with biological substances, and no difference in the deposition amount of biological substances was observed.

[0058] A second group of plates is shown in FIG. 7, which also shows the evolution of biological substances embedded in the plates over time.

[0059] As can be observed on the 20th day of the immersed plates, the control plate, M2 plate with S1 surface, and M2 plate with S2 surface do not contain any biological substances.

[0060] On the 48th day, the control and M2 plates with S2 surface were partially covered with a thin layer of biological substances, while the plate M2 with surface S1 began to show a very small amount of deposited biological substances.

[0061] On the 63rd day, the control and M2 plates with S2 surface were completely covered with the deposited biological substances. It can be seen that the amount of biological substances on the M2 plate with S1 surface has a very thin layer of deposited biological substances.

[0062] On the 73rd day, the control plate and the plate M2 with S2 surface were completely covered with a thick layer of biological substances. The plate M2 with S1 surface showed a slight increase in biological substances compared to the inspection on the 63rd day.

[0063] On the 97th day, the control plate and the plate M2 with surface S2 were completely covered with biological substances showing a considerable increase compared to the visual inspection on the 73rd day. The plate M2 with surface S1 presents on the exposed surface some regions with a thin layer of biological substances and adjacent regions with a thicker layer.

[0064] These on-site tests surprisingly found that the M2 plate has much higher efficiency than M1. The M2 plate uses copper oxide nanoparticles, which are first obtained by elemental copper nanoparticles or metallic copper in the oxidation state 0, and then these are used to obtain copper nanoparticles, which are processed to promote oxidation to the Cu +2 state. This oxidation state enables the oxidized nanoparticles to be more aggressive towards microorganisms, which results in a significant reduction in the fouling rate, thereby increasing the service life of wires or metal cables coated with this material. This is consistent with what was observed in laboratory tests.

[0065] Furthermore, these on-site tests surprisingly found that the influence of the surface roughness of the M1 and M2 materials is a very important aspect that must be considered when coating wires or metal cables. In either case, the smooth surface S1 is the surface that exhibits a greater antifouling effect compared to the rough surface S2.

[0066] The comparative analysis of Figures 6 and 7 shows that the fouling rate of plate M2 is significantly lower than the fouling rate of plate M1. It can be observed that the amount of material contaminated on plate M1 on the 48th day is very similar to the amount of material contaminated on plate M2 on the 97th day. This means that there is an extension of about 50 days in the service life of this material.

[0067] As described above, the nets are cleaned every 15 days in summer and every two months in winter according to Chilean regulations. This means that divers equipped with pressure washers have to dive in to clean them on-site, which increases the cost of operating each cage boat. The nets are also removed and cleaned at the factory as required by Chilean law. Cleaning can also be done using a robotic cleaning system based on a rotating disk, which emits water through their nozzle jets under pressure. However, this also affects the operating cost of the fish farming cages.

[0068] The nets containing antifouling paint are removed and replaced every four months in summer and every six months in winter. The nets containing antifouling paint are prohibited from being cleaned on site because when the paint peels off the net, chemical residues are generated, which cause fouling of the water around the cage and on the seabed. Therefore, they should be cleaned only at the net factory, as required by Chilean law.

[0069] The wire netting coated with a plastic containing copper oxide nanoparticles does not generate chemical waste during cleaning because it discharges electric charges. This does not pollute the environment.

[0070] Copper oxide nanoparticles do not cause pollution because their biocidal action is caused by the electric charges they generate, and no copper is released during cleaning, so there is no risk of copper pollution as a heavy metal.

[0071] The wire netting coated with a plastic containing copper oxide nanoparticles results in a reduced cleaning frequency, reduces maintenance costs, and thus reduces the operating costs of each cage raft.

[0072] The nets made of M2 material are lighter, have less structural stress without the nets collapsing, and the fish are safer. Furthermore, water flows freely through the nets, increasing the oxygenation of the water inside the cages.

[0073] Accordingly, the plastic material having copper oxide nanoparticles with a smooth surface has the best performance with respect to the desired properties, which reduces the fouling rate of hydrobiological organisms in a metal core (the core is a wire or cable) coated with plastic.

[0074] Exemplary preferred embodiments of the present invention As shown in FIGS. 8 and 9, the core (1) is formed by a single metal wire (2) coated with a plastic coating (3) containing copper oxide nanoparticles. FIG. 10 shows that the metal core (1) can be formed by a plurality of metal wires (2) coated with a plastic coating (3) containing copper oxide nanoparticles. FIG. 11 shows that the metal core (1) may be a metal cable composed of a single strand (4) composed of a plurality of wires (2), and the strand (4) is coated with a plastic coating (3) containing copper oxide nanoparticles.

[0075] FIG. 12 shows that the core (1) may be formed by a cable composed of a plurality of strands (4), each of the strands (4) is formed by a plurality of wires (2), and the strand (4) is coated with a plastic coating (3) containing copper oxide nanoparticles. The strands (4) shown in FIGS. 11 and 12 can have a core (5) made of glass fiber or the like.

[0076] In one embodiment of the present invention, the net (6) is composed of metal wires (2) coated with a plastic lining or coating (3) having copper oxide nanoparticles used for fish cages. In order to manufacture the net (6), as shown in FIGS. 13 and 14, it is necessary to fold a wire strand (7) having a plastic lining to form a rhombus that generates an opening of the net (6). During the folding process, the plastic lining or coating (3) having nanoparticles of copper oxide bends (8) may be damaged, which causes a reduction in the service life of the net (6). Therefore, it is also important to have the correct size and dosage of copper oxide nanoparticles in the plastic matrix so that the lining or coating (3) has appropriate resistance.

[0077] Therefore, it is a prerequisite that the plastic containing copper oxide nanoparticles can withstand both extrusion and wire bending.

[0078] Copper oxide nanoparticles are dispersed in a plastic lining or coating and have a size of 50 to 200 nanometers (nm).

[0079] In the manufacturing process, copper nanoparticles having a size between 50 and 200 nm are mixed with a thermoplastic material to form a material that is applied to a zinc-plated wire for the purpose of having uniformly dispersed nanoparticles along the coating. As shown in Figure 1, some of the nanoparticles group together to form aggregates reaching a size between 500 and 1000 nm. The plastic used is preferably high-density polyethylene (HDPE), medium-density polyethylene (MDPE), low-density polyethylene (LDPE), polyvinyl chloride or PVC, or other plastic polymers. The copper nanoparticles mixed with the plastic are poured onto the zinc-plated wire and then fed into a hopper that supplies an extruder through which the zinc-plated wire passes, thus forming a uniform coating on the wire. The zinc-plated wire passing through the extruder has a diameter between 0.5 and 10.0 millimeters, and the plastic coating by the copper nanoparticles has a thickness between 0.5 and 1.0 millimeters. The wire used in the manufacture of the net has a final diameter of the plasticized wire between 1.5 and 12.0 millimeters. Preferably, the zinc-plated wire passing through the extruder has a diameter of 2.1 millimeters, and the plastic coating by the copper nanoparticles has a thickness between 0.5 and 0.7 millimeters. The wire used in the manufacture of the net has a final diameter of the plasticized wire between 3.1 and 3.5 millimeters.

[0080] The copper oxide nanoparticles are uniformly dispersed throughout the plastic matrix, and there is no surface concentration or concentration difference with respect to the internal region of the plastic.

[0081] The concentration of the nanoparticles in the plastic is between 10 and 20 wt%.

[0082] With the above dimensions, it can be confirmed that the metal wire coated with copper oxide nanoparticles has an antifouling effect and has good mechanical conditions for both extrusion and folding.

Claims

1. A core covered with a plastic lining or coating that reduces the rate of fouling of marine and freshwater biological materials, intended for the manufacture of nets and anchor cables or anchors for fish farming, the plastic coating comprises copper oxide nanoparticles dispersed throughout a plastic matrix having a size between 50 and 200 nanometers (nm) and a concentration of 10 to 30% by weight; the plastic coating further comprises aggregated copper oxide nanoparticles with a size between 500 and 1000 nm; The copper oxide nanoparticles are Cu ＋２ Oxidized to the state A core covered with a plastic lining or coating, characterized in that said plastic coating has a smooth surface.

2. 2. The core coated with a plastic lining or coating according to claim 1, characterized in that the copper oxide nanoparticles have an ellipsoidal, spherical or amorphous shape.

3. 2. The core covered with a plastic lining or coating according to claim 1, characterized in that the plastic is high density polyethylene (HDPE).

4. 2. The core covered with a plastic lining or coating according to claim 1, characterized in that the plastic is medium density polyethylene (MDPE).

5. 2. The core covered with a plastic lining or coating according to claim 1, characterized in that the plastic is low density polyethylene (LDPE).

6. 2. The core covered with a plastic lining or coating according to claim 1, characterized in that the plastic is polyvinyl chloride or PVC.

7. 2. The core covered with a plastic lining or coating according to claim 1, characterized in that the core is a wire.

8. 8. A core coated with a plastic lining or coating according to claim 7, characterized in that the wire is a galvanized metal wire.

9. A core covered with a plastic lining or coating according to any one of claims 7 or 8, characterized in that the wire has a diameter between 0.5 mm and 10.0 mm.

10. 10. The plastic lining or coating of claim 9, wherein the wire has a diameter of 2.1 millimeters.

11. 2. The core covered with a plastic lining or coating according to claim 1, characterized in that the plastic coating with copper oxide nanoparticles has a thickness of 0.5 to 0.7 millimeters.

12. 8. The core covered with a plastic lining or coating according to claim 7, characterized in that the wire with the plastic coating has a diameter between 2.6 and 3.8 millimeters.

13. 8. The core covered with a plastic lining or coating according to claim 7, characterized in that the metal wire with the plastic coating has a diameter between 3.1 and 3.5 millimeters.

14. 2. The plastic lining or coating core of claim 1, wherein the core is made up of a plurality of wires.

15. 2. The plastic lining or coating core of claim 1, wherein the core is comprised of a cable constructed from a single strand, the single strand being comprised of multiple wires.

16. 2. The plastic lining or coating core of claim 1, wherein the core is formed by a cable, the cable is formed by a plurality of strands, and the plurality of strands is formed by a plurality of wires.

17. 17. A core covered with a plastic lining or coating according to claim 15 or 16, characterized in that the strand has a core made of glass fibre or the like.

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