GB2633970A

GB2633970A - Metal core coated with plastic lining having copper oxide nanoparticles

Info

Publication number: GB2633970A
Application number: GB2417531.7A
Authority: GB
Inventors: Armando Cea Winkler Gonzalo; Francisco Saavedra Castaldini Álvaro
Original assignee: IND CHILENAS DE ALAMBRE INCHALAM S A
Current assignee: IND CHILENAS DE ALAMBRE INCHALAM S A
Priority date: 2022-05-09
Filing date: 2023-03-28
Publication date: 2025-03-26
Also published as: NO20241113A1; ZA202409179B; GB202417531D0; MX2024013694A; CA3252596A1; AU2023266426A1; WO2023216005A1; JP2025517159A

Abstract

The present invention relates to a core covered with a plastic lining or coating and intended for manufacturing nets to farm fish, as well as securing or anchoring cables. The core slows down the rate of fouling by freshwater and marine biological materials, wherein the plastic coating comprises copper oxide nanoparticles that are distributed throughout the plastic matrix and have a size between 50 and 200 nanometres (nm) with a concentration of 10 to 30% by weight. The copper oxide nanoparticles may be agglomerated, forming an agglomerate having a size between 500 and 1000 nm. The copper oxide nanoparticles are oxidised to a Cu+2 state.

Description

METAL CORE COVERED WITH PLASTIC LINING THAT HAS COPPER OXIDE NANOPARTICLES.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a metal core coated with a plastic liner or coating which has copper oxide nanoparticles arranged inside it, intended to reduce the fouling rate of marine and freshwater macro and microorganisms. More specifically, the present invention relates to a metal core coated with plastic that has copper oxide nanoparticles that act as antifouling, the core being a metal wire, a metal cable made up of a single strand which in turn is made up of a plurality of wires or a cable made up of a plurality of strands, in order to extend its useful life.

BACKGROUND OF THE INVENTION

In the maritime, fishing, aquaculture and aquaculture industries, marine structures such as fish farm cages, oil platforms and towers supporting wind mills among several others, have elements that are exposed to water which require constant cleaning or replacement, because marine macro and microorganisms are deposited on the outer surface.

In many of these applications, the structures are anchored to the seabed by cables which suffer from the problem of fouling.

On the inside, this type of structures are, for example, oil platforms and towers of windmill supports, among others. Also, the cage rafts for the cultivation of aquaculture species must be anchored to the seabed or fixed to the rocks on the banks of the aquaculture centers, so they are exposed to the problem from the fouling of aquaculture biological material.

Specifically, in the fish farming industry, fish farming cages are formed by a floating structure that has nets made of metal wires on its perimeter edge and under water, which form a confinement of a volume of water intended 10 to house fish that are in the process of growth.

The fact that the wire mesh is located under water causes marine biological materials (hydrobiological organisms) to become embedded over time, which causes the mesh to increase in weight and, therefore, also causes an increase in mechanical stresses. In addition, the network openings are closing and prevents circulation of water which affects to fish that are in culture.

To overcome this problem, the nets are washed every 15 days in summer and every two months in winter. This means that divers with pressure washers must dive in to clean them on site, which increases the cost of the operation of each cage raft.

The nets are also removed and cleaned in net workshops.

Washing can also be done with robotic cleaning systems based on rotating discs, which launch through their nozzles high-pressure water jets. However, this also influences the operating costs of fish farming cages.

There are nets that have a layer of antifouling paint, but they cannot be cleaned on site (according to Chilean regulations) because it causes a chemical contamination in the water due to the effect of removing this layer. Therefore, they should only be washed in net workshops that contain water treatment plants (waste and rises). For this reason, nets with antiflouling paint are removed and replaced approximately every 4 months in summer and every 6 months in winter; this frequency may vary (increase (usually) depending on fouling aggressiveness levels.

The fouling material is first constituted as a precursor by a biofilm made up of bacteria, microalgae and microorganisms in general, then the primary fouling organisms such as mollusks (e.g. mussels), crustaceans (e.g. picorocos), ascidians (e.g. piures type), spores of macroalgae, hydrozoans, bryozoans, etc., which in the larval state (animals) or spores (algae) attach to substrates (such as plastic, HDPE, wood, boat hulls, floats or plastic flotation pipes in salmon ponds, etc.) and begin to grow, generating the actual fouling (macrofouling).

To prevent the structure floating cage raft to shift, anchor cables are used which also have the problem of fouling, substantially reducing the useful life.

Therefore, a first objective of the present invention is to provide a metal core comprising a plastic lining or coating containing copper oxide nanoparticles inside, where said core is a metal wire to be used in the manufacture of nets for rafts and cages intended for fish farming, which reduces the speed of fouling (antifouling) of marine macro and microorganisms, in such a way as to prolong the useful life and reduce network replacement periods.

A second objective of the present invention is to provide a metal core comprising a plastic lining or coating containing copper oxide nanoparticles therein, wherein said core is a metal cable composed of a single strand formed, in turn, by a plurality of metal wires or a metal cable made up of a plurality of strands, to be used in anchoring marine structures, which reduces the rate of fouling (antifouling) of marine macro and microorganisms, in such a way as to prolong the useful life and reduce the replacement periods of the cable.

A third objective of the present invention is to provide a network for Cage rafts intended for fish farming, which is made up of a metal wire that has a plastic lining or coating which has copper oxide nanoparticles, where said plastic lining with copper nanoparticles has sufficient resistance so that the plastic does not damage or break during the extrusion process that is carried out together with the metal wire and during the folding of the metal wire strands with the plastic coating to form the weave of the net.

One of the possible solutions to this type of problem is to use copper since it is widely known in the state of the art that copper has biocidal properties and, for this reason, it is used in a large number of applications. Among these applications is its use as nanoparticles to add them to various materials, including plastic, in such a way as to transfer this property. However, in cases where the object to be coated is under water, this property is rapidly lost so it is necessary to find an alternative to extend the useful life of the elements that have been coated with this plastic. On the other hand, in the state of the art there have been attempts to solve the problem of fouling using nanoparticles of various metals, including copper. For example, CN111926407A discloses a method of processing nanosized antifouling copper-nickel plastic filaments containing grafted polyguanidine salt. The method includes three processes of raw material compounding, melt spinning and stretching, and heat forming. In addition, the polyethylene particles of high density, grafted polyguanidine salt particles/polyethylene and surface modified copper-nickel alloy nanoparticles as the main raw material, a composite material with the synergistic antifouling effect is first obtained, and then the synergistic antifouling plastic filaments are obtained after wire drawing technology. Synergistic antifouling filaments carry out a synergistic antifouling treatment directed at algae and other fouling organisms. The plastic filament obtained by this procedure prevents fouling organisms from adhering to the surface of the fish farming facility and their proliferation in the net. While it is true that this document discloses a method for processing plastic filaments having nanosized copper and nickel nanoparticles containing grafted polyguanidine salt, to obtain a plastic filament with an antifouling property, does not specifically disclose a metal wire having a plastic coating or sheath which comprises only copper oxide nanoparticles. The rate of fouling of marine and freshwater biological materials is also not disclosed.

On the other hand, in document US4603653 a marine antifouling material is disclosed to provide an antifouling surface for its use in sea water, comprising a layer of elastomeric carrier material inert, insoluble in water, flexible and extensible, having an outer surface and an opposite inner surface and having embedded therein a single layer of a plurality of copper or copper alloy particles, all said particles being essentially of the same size in the range of 0.5 to 3.0 millimeters, the ratios of the major dimensions of said particles all being in the range of about 0.7 to 1.0, and said single layer having a maximum thickness equal to the size of said particles, all of the particles being exposed on the outer surface of said carrier material to provide a multiplicity of discrete copper areas of size generally uniform on the exterior surface of the inert material continuum, said areas being spaced between 0.5 and 0.75 millimeters, the total area of the spaced copper areas being between 20 and 40% of the total area of the antifouling surface of said antifouling material, said layer of particles being spaced from the opposite interior surface of said material Carrier so that said surface inside has no exposed copper in the same, and wherein said antifouling surface of said antifouling material is accessible to seawater and the multiplicity of copper areas spaced therein retard or prevent marine growth on said antifouling surface. The exposed surface with copper particles of this material can be provided by embedding, in a support material, such as a woven or knitted wire mesh, or an expanded metal grid. While it is true that this document discloses a material with a layer of copper particles, where said material can be applied to a metal product such as a mesh wire, there is no indication that the material comprises only copper oxide nanoparticles as the only antifouling element, that the nanoparticles are homogeneously dispersed in the polymeric matrix, nor is it disclosed how slow the fouling speed of marine and freshwater biological materials is. Likewise, this document discloses a material that has copper particles in the range of 0.5 to 3 millimeters what is far from nanotechnology.

Document CL202100106 describes copper nanoparticles, nanopolymers comprising them, disinfectant composition and surface protective antimicrobial adhesive film/film comprising them, including such non-rigid surfaces, fabrics, plastic films, nets and the like that have an antifouling property. This film can also be included in hard surfaces of daily or public use such as counters, handrails, handles, toilets, urinals, and the like. While it is true that this document describes that nanoparticles can be incorporated into films of plastic and nets, among others, there is no specific disclosure of a metal wire coated with copper oxide nanoparticles that acts as an anti-fouling element, much less is there any mention of the speed of fouling of marine and freshwater biological materials.

None of the state-of-the-art documents disclose a core metallic wire or cable having a plastic lining or coating, where the plastic has only copper oxide nanoparticles, providing a much simpler solution than the prior art, to provide a metal wire or cable with antifouling properties, in such a way as to reduce the speed of fouling of marine and freshwater biological materials, thereby increasing the useful life.

REVIEW OF THE INVENTION

The present invention relates to a metal core coated with a plastic liner or coating which has copper oxide nanoparticles arranged inside it, intended to reduce the fouling rate of marine and freshwater macro and microorganisms. More specifically, the present invention relates to a plastic coated core having copper oxide nanoparticles that act as an antifouling, the core being a wire, a cable made up of a single strand which in turn is made up of a plurality of wires or a cable made up of a plurality of strands, in order to extend its useful life.

The copper nanoparticles used in the invention are obtained primarily by means of elemental copper or metallic copper nanoparticles in state 0. These nanoparticles are treated to accelerate their oxidation and leave them in the copper +2 (Cu+2) state (hereinafter copper oxide nanoparticles).

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

In the manufacturing process, copper oxide nanoparticles have a size of between 50 to 200 nm, they are mixed with the plastic material which is hot, to form the material that will be applied on the galvanized wire in order to have a uniform distribution of particles along the coating. When the nanoparticles enter the polymeric matrix, some of them group together forming agglomerates that reach a size of between 500 to 1000 nm, as shown in the photograph in Figure 1. 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 of between 10 and 30% by weight.

The plastic with copper oxide nanoparticles is poured into a hopper that feeds an extruder to hot extrude the plastic onto the galvanized wire, thus forming a uniform coating on said wire.

Galvanized wire passing through the extruder has a diameter of between 0.5 and 10 millimeters and the plastic coating with copper oxide nanoparticles has a thickness of 0.5 to 1.0 millimetres. The wire used in the manufacture of nets has a final diameter of the plasticised wire of between 1.5 and 12 millimetres.

DESCRIPTION FROM THE DRAWINGS

Figure 1 shows a photograph of the plastic material with copper oxide nanoparticles with a size between 50 to 200 nm, where some of them are grouped together forming agglomerates of copper oxide nanoparticles that reach a size between 500 to 1000 nm.

The Figure 2 shows a photograph of the test specimens or plates of materials to be tested inside a peltri plate.

Figure 3 shows a photograph of culture plates of the materials tested with Eschenthia coli (E. coli) bacteria.

Figure 4 shows a photograph of culture plates of the materials tested with bacteria Tenacibaculum dicentrarchi (T.dicentrarchi).

Figure 5 shows a photograph of culture plates of the materials tested with Vibrio sp. bacteria.

Figure 6 shows a photograph of the plastic plates with elemental copper nanoparticles in field tests, to visualize the amount of embedded marine biological material over a time interval of 20 to 97 days. Figure 7 shows a photograph of the plastic plates with copper oxide nanoparticles in field tests, to visualize the amount of marine biological material embedded in a time interval of between 20 and 97 days.

Figure 8 is a perspective view of a wire covered by a plastic sheath. 5 The Figure 9 is a cross-sectional view of a wire covered by a plastic sheath. Figure 10 is a cross-sectional view of a plurality of wires covered by a plastic sheath.

Figure 11 is a cross-sectional view of a coated cable per a plastic sheath, said cable being composed of a single strand.

Figure 12 is a cross-sectional view of a cable covered by a plastic sheath consisting of a plurality of strands.

Figure 13 is a front elevation view of a net for use in a fish-raising cage. 15. The Figure 14 is a front elevation view showing the manner in which the folds of a wire net are made when making a net for fish cages intended for fish farming.

DESCRIPTION OF THE INVENTION

The present invention relates to a metal core coated with a plastic lining or coating which has copper oxide nanoparticles arranged inside it, intended to reduce the fouling rate of marine and freshwater macro and microorganisms. More specifically, the present invention relates to a metal core coated with plastic that has copper oxide nanoparticles that act as antifouling, the core being a metal wire, a metal cable made up of a single strand which in turn is made up of a plurality of wires or a cable made up of a plurality of strands, in order to lengthen its shelf life.

As mentioned above, the application of copper nanoparticles to plastic materials is known in order to transfer the biocidal properties of copper to LI IC IdLLCI. LIKevvise, the use of plastic with copper nanopartic.--for fish farming or fishing nets that have antifouling properties. However, none of them mention the type of copper nanoparticle to be used, nor do they refer to the growth rate of marine or freshwater biological material or the application to a wire or metal cable.

The biological material that adheres to the surface of any material under water, is formed with a precursor that is a biofilm made up of bacteria, microalgae and microorganisms in general. After that, primary encrusting organisms such as algae spores, mollusc and crustacean larvae, among others, molluscs, crustaceans and ascidians among others adhere. Therefore, if microorganisms are eliminated, the formation of algae, mollusks and crustaceans. It is for this reason that, knowing that copper is a biocidal metal, it is highly advantageous to investigate its behavior in its various forms.

Since the objective of the present invention is to coat a metal wire or cable with a plastic coating, then the copper must be dispersed in the polymer matrix. For this purpose, the plastic material with copper micro and nanoparticles was investigated.

For this purpose, laboratory tests were carried out, where test tubes in the form of high-density polyethylene (HDPE) plates were used.

to which both copper microparticles and copper nanoparticles were added.

The copper nanoparticles used in the invention are first obtained by means of elemental copper nanoparticles or metallic copper in state 0. These nanoparticles are treated to accelerate their oxidation and leave them in the Cu+2 state (hereinafter copper oxide nanoparticles). This Oxidation allows the nanoparticle to be more aggressive against microorganisms, attacking them much faster.

A first group of plates was formed with HDPE containing elemental or metallic copper nanoparticles, a second group of plates was formed with HDPE containing copper oxide nanoparticles, a third group of plates was formed with HDPE containing a polyamide with 10% of a compound based on copper microparticles and a fourth group of plates was formed with HDPE containing a polyamide with 30% of a compound based on copper m icroparticles.

The size of copper nanoparticles in the first two groups of plates was between 50 and 200 nm and with a concentration of nanoparticles in the HDPE of between 10% and 20% by weight. As shown in the photograph in Figure 1, there are some nanoparticles that are grouped together to form agglomerates that reach a size of between 500 and 1000 nm.

Laboratory tests To carry out the laboratory tests, a methodology of evaluation, based on ISO 22196:2011 "Measurement of antibacterial activity on plastic and other nonporous surfaces" (Test of antimicrobial activity on plastics and other nonporous surfaces), adapted to prevalent bacteria in marine environments, using as a reference the strain of Escherichia coli (E. coli) ATCC 25922 and with respect to two strains of bacteria isolated from the Chilean marine environment to the strains: Tenacibaculum dicetrarchi (T. dicetrarchi) and Vibrio sp.

E. Coll bacteria were grown on Trypticase Soybean (TSA) solid media and T. dicentrarchi bacteria and Vibrio sp. bacteria were grown on Marine Agar (MA).

Each bacteria or pathogen was evaluated in independent tests for each material to be studied, as indicated in Table 1 below: Type of material to be tested Labeling material Plastic with nanoparticles of elemental or metallic copper M1 Plastic with oxide nano particles copper M2 Plastic with 10% copper micro particles PAGE-10 Plastic with 30% copper microparticles PAGE-30 Plastic without micro and nanoparticles Control Table 1. Identification of the materials to be used in the tests.

The plates prepared for the tests, including the control without micro and nanoparticles, had a size of 50x50 mm and a thickness of less than 10 mm. In each assay, the plates were placed inside a petri dish sterile and a bacterial inoculum was prepared in its respective broth (Triptana Broth-Soy broth for E.cori bacteria and marine broth for T. dicentrarchi and Vibrio sp. bacteria) of which 400 pL was added on the surface of each plate, as shown in figure 2. The volume was spread with a plastic loop and the inoculum was covered with a 40x4Omm piece of film which was pressed to cover the entire surface of each plate. Each petri dish was closed and then immediately proceeded with bacterial recovery, to have a measurement at initial time (TO).

Subsequently, it was incubated for 24 hours (T24) at 35°C in the case of E. coli and 18°C in the case of T dicentrarchi and Vibrio sp.

For bacterial recovery, the film and specimen were washed with 8 mL TSB recovery broth and marine broth, with 0.7% tween 80, taking care to repeatedly clean the entire specimen. Subsequently, the viable bacteria count was performed, for which 100 pL of medium with recovered bacteria were taken and 10-fold base dilutions were made. Each dilution was plated in triplicate (replicates) on a Tryptone Soy Agar (TSA) plate and in a marine environment (AM) plate according to the bacterial species, as indicated previously.

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

me ualLAAlcalui is of results were carried out following the 22196:2011 standard, determining in each case the antibacterial activity (R), based on the viable bacteria count (N) according to the following equation (I): N= (100 xCxD xV)/A (I) Where: N = Number of viable bacteria recovered per cm2 of the specimen evaluated.

C = Average plate count for the replicates D = Dilution factor for the plates.

V = Volume (mL) of culture broth added in the tests A = Surface (mm2) of the polyethylene film used in the test for covering the specimen.

The results for each bacteria are shown in Table 2 to 4.

following: Material Replica Time ufc/mL ufc/mL C D N Value (Hrs) obtained (cm2) logarithm of

N

M-1 1 0 1.00E+06 4.00E+04 1 1.00E+06 500000.0 5.70 2 0 9,00E+05 3.60E+04 9 1.00E+05 450000.0 5.65 3 0 6.33E+05 2.53E+04 6.33 1.00E+05 316500,0 5.50 1 0 4.00E+05 1.60E+04 4 1.00E+05 200000.0 5.30 2 0 1.20E+05 4.80E+03 1,2 1.00E+05 60000.0 4.78 M-2 3 0 6.00E+05 2.40E+04 6 1.00E+05 300000.0 5.48 PAGE-10 0 1.00E+06 4.00E+04 1 1.00E+06 500000.0 5.70 2 0 1.50E+06 6.00E+04 1.5 1.00E+06 750000,0 5.88 3 0 1.00E+06 4.00E+04 1 1.00E+06 500000.0 5.70 PAGE-30 1 0 2.13E+06 8.52E+04 2.13 1.00E+06 1065000,0 6.03 2 0 3.67E+05 1.47E+04 3.67 1.00E+05 183500,0 5.26 3 0 4.33E+05 1.73E+04 4.33 1.00E+05 216500,0 5.34 Control 1 0 5.67E+05 2.27E+04 5.67 1.00E+05 283500,0 5.45 2 0 5.67E+05 2.27E+04 5.67 1.00E+05 283500,0 5.45 3 0 6.33E+05 2.53E+04 6.33 1.00E+05 316500,0 5.50 M-1 1 24 2.60E+08 1.04E+07 2.6 1.00E+08 130000000,0 8,11 2 24 8.33E+07 3.33E+06 8.33 1.00E+07 41650000,0 7.62 3 24 2.70E+08 1.08E+07 2.7 1.00E+08 135000000,0 8.13 M-2 24 2.00E+07 8,00E+05 2 1.00E+07 10000000,0 7.00 2 24 8.67E+07 3.47E+06 8.67 1.00E+07 43350000,0 7.64 3 24 6.67E+07 2.67E+06 6.67 1.00E+07 33350000,0 7.52 PAGE-10 1 24 4.00E+07 1.60E+06 4 1.00E+07 20000000,0 7.30 2 24 7.67E+07 3.07E+06 7.67 1.00E+07 38350000,0 7.58 3 24 7,00E+07 2.80E+06 7 1.00E+07 35000000,0 7.54 PAGE-30 1 24 6.00E+07 2.40E+06 6 1.00E+07 30000000.0 7.48 2 24 5.33E+07 2.13E+06 5.33 1.00E+07 26650000,0 7.43 3 24 5.67E+07 2.27E+06 5.67 1.00E+07 28350000,0 7.45 Control 1 24 4.60E+08 1.84E+07 4.6 1.00E+08 230000000,0 8.36 2 24 2.67E+08 1.07E+07 2.67 1.00E+08 133500000,0 8.13 3 24 3.00E+08 1.20E+07 3 1.00E+08 150000000,0 8.18 Table 2. Counting results and calculation of the logarithmic value of N in E. coli testing.

Time(H ufc/mL ufc/mL Value Material Replica rs) obtained (cm2) C D N logarithm of N M-1 1 0 4.67E+05 1.87E-F04 4.67 1.00E+05 233500,0 5.37 2 0 3.67E-F05 1.47E-F04 3.67 1.00E-F05 183500,0 5.26 3 0 2.33E-F05 9.32E-F03 2.33 1.00E-F05 116500,0 5.07 M-2 1 0 4.67E+05 1.87E+04 4.67 1.00E+05 233500,0 5.37 2 0 3.33E-F05 1.33E-F04 3.33 1.00E-F05 166500,0 5.22 3 0 3.33E-F05 1.33E-F04 3.33 1.00E-F05 166500,0 5.22 PAGE-10 0 1.67E+05 6.68E+03 1.67 1.00E+05 83500,0 4.92 2 0 1.33E+05 5.32E+03 1.33 1.00E+05 66500,0 4.82 3 0 2.00E-F05 8,00E-F03 2 1.00E-F05 100000.0 5.00 PAGE-30 1 0 2.33E-F05 9.32E-F03 2.33 1.00E-F05 116500,0 5.07 2 0 2.00E+05 8,00E+03 2 1.00E+05 100000.0 5.00 3 0 2.00E-F05 8,00E-F03 2 1.00E-F05 100000.0 5.00 Control 1 0 4.00E+05 1.60E+04 4 1.00E+05 200000.0 5.30 2 0 3.33E+05 1.33E+04 3.33 1.00E+05 166500,0 5.22 3 0 4.33E+05 1.73E+04 4.33 1.00E+05 216500,0 5.34 M-1 1 24 3.00E+05 1.20E+04 3 1.00E+05 150000,0 5.18 2 24 1.67E-F05 6.68E-F03 1.67 1.00E-F05 83500,0 4.92 3 24 4.00E-F06 1.60E-F05 4 1.00E-F06 2000000.0 6.30 M-2 1 24 4.00E-F06 1.60E-F05 4 1.00E-F06 2000000.0 6.30 2 24 1.33E-F05 5.32E-F03 1.33 1.00E-F05 66500,0 4.82 3 24 6.70E+03 2.68E+02 6.7 1.00E+03 3350.0 3.53 PAGE-10 1 24 2.33E-F04 9.32E-F02 2.33 1.00E-F04 11650.0 4.07 2 24 4.33E-F05 1.73E-F04 4.33 1.00E-F05 216500,0 5.34 3 24 4.33E-F05 1.73E-F04 4.33 1.00E-F05 216500,0 5.34 PAGE-30 1 24 4.00E+05 1.60E+04 4 1.00E+05 200000.0 5.30 2 24 4.00E-F05 1.60E-F04 4 1.00E-F05 200000.0 5.30 3 24 2.67E-F04 1.07E-F03 2.67 1.00E-F04 13350.0 4.13 1 24 2.00E-F07 8,00E+05 2 1.00E-F07 10000000,0 7.00 2 24 1.67E+07 6.68E+05 1.67 1.00E+07 8350000,0 6.92 Control 3 24 2.33E+07 9.32E+05 2.33 1.00E+07 11650000,0 7.07 Table 3. Counting results and calculation of the logarithmic value of N in tests with T. dicentrarchi.

Material Replica Time(Hrs) ufc/mL cfu/mL C D N Logarith obtained (cm2) m value of N M-1 1 0 1.50E+05 6.00E+03 1.50 1.00E+05 75000 4.88 2 0 1.66E+05 6.64E+03 1.66 1.00E+05 83000 4.92 3 0 1.70E+05 6.80E+03 1.70 1.00E+05 85000 4.93 M-2 1 0 1.10E+05 4.40E+03 1.10 1.00E+05 55000 4.74 2 0 1.20E+05 4.80E+03 1.20 1.00E+05 60000 4.78 3 0 1.17E+05 4.68E+03 1.17 1.00E+05 58500 4.77 PAGE-10 1 0 1.37E+05 5.48E+03 1.37 1.00E+05 68500 4.84 2 0 1.50E+05 6.00E+03 1.50 1.00E+05 75000 4.88 3 0 1.60E+05 6.40E+03 1.60 1.00E+05 80000 4.90 PAGE-30 1 0 1.37E+05 5.48E+03 1.37 1.00E+05 68500 4.84 2 0 1.40E+05 5.60E+03 1.40 1.00E+05 70000 4.85 3 0 1.50E+05 6.00E+03 1.50 1.00E+05 75000 4.88 Control 1 0 1.53E+05 6.12E+03 1.53 1.00E+05 76500 4.88 2 0 2.33E+05 9.32E-F03 2.33 1.00E+05 116500 5.07 3 0 1.63E+05 6.52E+03 1.63 1.00E-F05 81500 4.91 M-1 1 24 1.10E+07 4.40E+05 1.10 1.00E-F07 5500000 6.74 2 24 7.30E+06 2.92E+05 7.30 1.00E-F06 3650000 6.56 3 24 8.60E+06 3.44E+05 8.60 1.00E+06 4300000 6.63 M-2 1 24 5.30E+05 2.12E+04 5.30 1.00E-F05 265000 5.42 2 24 6.00E+04 2.40E+03 6.00 1.00E+04 30000 4.48 3 24 2.60E+03 1.04E+02 2.60 1.00E-F03 1300 3.11 1 24 1.50E+07 6.00E+05 1.50 1.00E-F07 7500000 6.88 PAGE-10 2 24 2,00E+06 8.00E+04 2.00 1.00E+06 1000000 6.00 3 24 4.30E+06 1.72E+05 4.30 1.00E+06 2150000 6.33 PAGE-30 1 24 9.60E+06 3.84E+05 9.60 1.00E+06 4800000 6.68 2 24 4.60E+06 1.84E+05 4.60 1.00E+06 2300000 6.36 3 24 8,00E+05 3.20E+04 8.00 1.00E+05 400000 5.60 Control 1 24 1.16E+07 4.64E+05 1.16 1.00E+07 5800000 6.76 2 24 1.10E+07 4.40E+05 1.10 1.00E+07 5500000 6.74 3 24 4.30E+06 1.72E+05 4.30 1.00E+06 2150000 6.33 Table 4. Counting results and calculation of the logarithmic value of N in Vibrio testing sp.

In this way, from the logarithmic value of the count of viable bacteria (N) in TO and T24, the antibacterial activity value or antibacterial activity value was calculated.

R, according to the following equation II indicated in the standard.

R = (Ut-U0) -(At -UO) = Ut -At) (II) Where: R = antibacterial activity UO = is the average of the base 10 logarithm of the number of viable bacteria in cm2 cells, recovered from a control sample immediately after inoculation.

Ut = is the average of the logarithm in base 10 of the number of viable bacteria in cm-2 cells, recovered from our control after 24 hours.

At = is the average of the logarithm in base 10 of the number of viable bacteria in cells cm2, recovered from a sample after 24 hours.

The higher the R value, the greater the antibacterial activity of the material is evaluated. The results are shown in Table 5 below: Material R value E. coil Tenacibaculu Vibrio sp. m

dicentrarchi Ml a 1 8 1.38 0.02 M2 0.79 2.75 2.07 PAGE-10 0.73 2.21 0.30 PAGE-30 0.77 2.21 0.42 CONTROL 0.0 0. 0 0.0 Table 5: Results of antibacterial activity in both materials These results show that the antibacterial resistance of the control plastic plate (without copper micro and nanoparticles) has zero effectiveness and that the plastic plate with copper oxide nanoparticles (M2) has the best antibacterial effectiveness.

This can be seen in figures 3, 4 and 5, where the bacterian crops are shown corresponding to the various essays, on which are carried out the counts for the determination of the value of R. In the case of Figure 3, the control plates, Ml, PAG-10 and PAG-30 have a considerable increase of bacteria in Escherichia coli (E. coli) bacteria in 24 hours (T24), while in the M2 plate the increase is very slight.

For the case of figure 4, the control plate has a considerable increase in the bacteria 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 both with the control plate as with the Ml, PAG-10 and PAG-30 plates.

Finally, for the case of Figure 5, the control plate and the M1 plate in 24 hours (T24) show a growth of almost two times compared to the start of the test (TO). A moderate effect is observed in the PAG -10 plates and PAG 30. The M2 plate shows practically no growth.

Based on the above, it is possible to state that plastic with copper oxide nanoparticles is the material that has the best biocidal effect compared to the materials tested.

In addition to laboratory tests, field tests were performed, to visualize the antifouling effect of plastic materials with copper nanoparticles. Field tests For the field tests to be performed, they were taken in consideration of materials with elemental or metallic copper nanoparticles and copper oxide nanoparticles, that is materials M1 and M2.

Field tests consisted of in immersing two groups in the sea of plastic plates. A first group of plastic plates consisting of a HDPE plate without copper nanoparticles, as a control material, a HDPE plate with nanoparticles of elemental or metallic copper (called M1) with a smooth surface (called S1) and a HDPE plate with nanoparticles of elemental or metallic copper (M1) with a rough surface (called S2) and; a second group of plastic plates consisting of a HDPE plate without copper nanoparticles, as a control material, a HDPE plate with copper oxide nanoparticles (called M2) with a smooth surface (S1) and a HDPE plate with copper oxide nanoparticles (M2) with a rough surface (S2). In these field tests, the plates were immersed in the sea and after 20 days they were taken out to observe the evolution of deposited biological material and take photographs to document such evolution. After that, the plates were submerged again. This operation was repeated at 48, 63, 73 and 97 days.

The first group of plates is shown in Figure 6, which illustrates the evolution of the biological material that is embedded in the plates as that time moves forward.

As can be observed on day 20 of submersion, the control plate, the Ml plate with Si surface and the Ml plate with S2 surface are completely free of biological material.

On day 48 the control and M1 plates with S2 surface are completely covered with a thin layer of biological material, while the M1 plate with Si surface begins to show a slight amount of deposited biological material. On day 63, the control plates and M1 with S2 surface and M1 with S1 surface are completely covered with deposited biological material.

It can be seen that the amount of biological material on plate M1 with surface S1 is less than on plate M1 with surface S2.

On days 73 and 97 the control plate, plate M1 with S1 surface and plate M1 with S2 surface are completely covered with biological material, with no difference in the amount of biological material being observed.

deposited.

The second group of plates is shown in Figure 7, which also illustrates the evolution of biological material that is embedded in the plates as time progresses.

5. As can be observed on day 20 of the plates being submerged, the control plate, M2 plate with S1 surface and M2 plate with S2 surface are completely free of biological material.

On day 48 the control and M2 plates with S2 surface are partially covered with a thin layer of biological material, while plate M2 with surface S1 begins to show a very slight amount of deposited biological material.

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

On day 73, the control plate, plate M2 with S2 surface, was completely covered with a thick layer of biological material. Plate M2 with S1 surface showed a slight increase in biological material compared to the inspection on day 63.

On day 97 the control plate, plate M2 with surface S2 are completely covered with biological material which shows a considerable increase compared to the visual inspection on day 73. Plate M2 with surface S1 presents on the exposed face some areas that have a thin layer of biological material and adjacent areas with thicker layers.

With these field tests it was surprisingly found that the M2 plate has a much higher efficiency than Ml. The M2 plate uses copper oxide nanoparticles, which are obtained first by means of elemental copper nanoparticles or metallic copper in state 0, which are then used to obtain the copper nanoparticles which are treated to accelerate their oxidation and leave them in the Cu+2 state. This oxidation state allows the oxidized nanoparticles to be more aggressive against microorganisms, which produces a considerable decrease in the fouling speed, thereby increasing the useful life of the wire or metal cable coated with this material.

This is consistent with what was observed in laboratory tests.

In addition, with these field tests it was surprisingly found that the effect of the surface roughness of the M1 and M2 materials is a very important aspect that must be considered when coating the wire or metal cable. In both cases, the smooth surface S1 is the one that presents a greater effect.

antifouling with respect to the rough surface S2.

A comparative analysis of Figures 6 and 7 shows that the rate of fouling of plate M2 is considerably lower than that of plate M1. It can be observed that the amount of material fouled in plate M1 on day 48 is very similar to the amount of material fouled in plate M2 on day 97. This implies that there is an extension in the useful life of this material of the order of 50 days.

As noted above, the nets are washed every 15 days in summer and every two months in winter, according to Chilean regulations. This means that divers with pressure washers must dive in to clean them in situ, which increases the cost of operating each cage raft. The nets are also removed and cleaned in workshops, as required by Chilean legislation. The washing also can be done with robotic cleaning systems based on rotating discs, which launch through their nozzles jets of water under pressure. However, this also influences the operating cost of fish farming cages.

Nets with antifouling paint are removed and replaced every 4 months in summer and every 6 months in winter. Nets with antifouling paint are prohibited from being washed on site because they generate chemical residues when the paint comes off the net accelerated as this causes contamination of the waters surrounding the cages and on the seabed. For this reason, they should only be washed in net workshops, as required by Chilean legislation.

Wire nets coated with a plastic containing copper oxide nanoparticles do not generate chemical waste when they are washed because they release electrical charges. This does not pollute the environment.

Copper oxide nanoparticles do not produce contamination, since the biocidal action is produced by the electrical charges they generate, which in turn does not generate risks of copper contamination as a heavy metal since no copper is released during washing.

Wire nets coated with a plastic containing copper oxide nanoparticles present a decrease in the frequency of washing and reduce maintenance costs, thus reducing the operating cost of each cage raft.

Nets made of M2 material are lighter, have less structural stress and the fish are safer, without the net collapsing. In addition, water flows freely through the net, increasing the oxygenation of the water inside the cage.

According to this, the plastic material with copper oxide nanoparticles with a smooth surface is the one that has the best performance with respect to the desired property, which is to reduce the speed of fouling of hydrobiological organisms in metal cores coated with plastic, the core being a wire or cable.

Example preferred embodiment of the invention As shown in Figures 8 and 9, the core (1) is formed by a single metal wire (2) which is coated by a plastic sheath (3) containing copper oxide nanoparticles. Figure 10 shows that the metal core (1) can be formed by a plurality of metal wires (2) which are coated by a plastic sheath (3) containing copper oxide nanoparticles. Figure 11 shows that the metal core (1) can be a metal cable composed of a single strand (4) which, in turn, is made up of a plurality of wires (2), said strand (4) being covered by a plastic sheath (3) containing copper oxide nanoparticles.

Figure 12 shows that the core (1) may be formed by a cable that is composed of a plurality of strands (4), each of said strands (4) being formed by a plurality of wires (2), wherein said strands (4) are covered by a plastic sheath (3) containing copper oxide nanoparticles. The strands (4) shown in figures 11 and 12, may have a core (5) made of fiberglass or similar.

In one embodiment of the invention, a network (6) is obtained consisting by metal wires (2) covered with a plastic lining or coating (3) which has copper oxide nanoparticles to be used in fish cages. To manufacture said net (6) it is necessary that the wire strands (7) with the plastic lining are folded to form the rhombuses that produce the openings of the net (6), as shown in figures 13 and 14. During the folding process, the plastic lining (3) with nanoparticles of copper oxide bend (8) can be damaged, which will cause a decrease in the useful life of the net (6). For this reason, 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 the appropriate resistance.

Therefore, it is a necessary condition that plastic with copper oxide nanoparticles can withstand both extrusion and wire bending.

Copper oxide nanoparticles are dispersed in the plastic liner or coating and have a size of 50 to 200 nanometers (nm).

In the manufacturing process, copper nanoparticles that have a size between 50 to 200 nm are mixed with the hot plastic material to form the material that will be applied to the galvanized wire with the object of having a uniform distribution of nanoparticles along the coating. As shown in Figure 1, some nanoparticles are grouped together to form an agglomerate that reaches a size of 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 in the galvanized wire is then fed into a hopper that feeds an extruder through which the galvanized wire passes, thus forming a uniform coating on the wire. The galvanized wire that passes through the extruder has a diameter of between 0.5 and 10.0 millimeters and the plastic coating with copper nanoparticles has a thickness of 0.5 to 1.0 millimeters. The wire that will be used in the manufacture of nets has a final diameter of the plasticized wire of between 1.5 to 12.0 millimeters. Preferably, the galvanized wire that passes through the extruder has a diameter of 2.1 millimeters and the plastic coating with copper nanoparticles has a thickness of 0.5 to 0.7 millimeters. The wire that will be used in the manufacture of nets, the final diameter of the plasticized wire is between3.1 to 3.5 millimeters.

Copper oxide nanoparticles are homogeneously distributed throughout the plastic matrix, with no surface concentration or concentration difference in relation to internal areas of the plastic.

The concentration of nanoparticles in plastic is between 10 and 20% by weight.

With the dimensions indicated above, it is possible to affirm that the metal wire coated with copper oxide nanoparticles has an antifouling effect and has good mechanical conditions, both for extrusion and folding.

Claims

CLAIMS1.-A core covered with a plastic liner or coating intended for manufacturing nets for fish farming and anchoring cables or anchor which decreases the rate of fouling of biological materials marine and freshwater, CHARACTERIZED because the plastic coating comprises copper oxide nanoparticles which are distributed throughout the plastic matrix, having a size between 50 to 200 nanometers (nm) with a concentration of 10 to 30% by weight.
2.- A coated core with a plastic liner or coating, depending on Claim 1, CHARACTERIZED in that said plastic coating further comprises copper oxide nanoparticles agglomerated in a size between 500 to 1000 nm.
3.- A core covered with a plastic liner or coating, as the claim 1 or 2, CHARACTERIZED because the oxide nanoparticles Copper are oxidized to a Cu+2 state.
4.- A core covered with a sheath or cladding plastic, according to claim 1, CHARACTERIZED in that said plastic coating has smooth surface.
5.-A coated core with a lining or covering plastic, according to claim 1, CHARACTERIZED in that said oxide nano particles of copper has an oval, spherical or amorphous shape.
6.-A core covered with a plastic lining or coating, as any of claims 1 to 5, CHARACTERIZED in that the plastic is high-density polyethylene (HDPE).
7. A core covered with a plastic liner or coating, as 5. anyone of claims 1 to 5, CHARACTERIZED because the plastic is medium density polyethylene (MDPE).
8.-A core covered with a plastic lining or coating, as any of claims 1 to 5, CHARACTERIZED in that the plastic is low-density polyethylene (LDPE).
9.-A core covered with a plastic lining or coating, as any of claims 1 to 5, CHARACTERIZED in that the plastic is polyvinyl chloride or PVC.
10.-A core coated with a plastic lining or coating, according to any of claims 1 to 9, CHARACTERIZED in that said core is a wire.
11.-A core covered with a sheath or cladding plastic, according to Claim 10, CHARACTERIZED in that said wire is galvanized metal wire.
12.-A core covered with a plastic lining or coating, as 20 any of claims 10 or 11, CHARACTERIZED in that said wire has a diameter of between 0.5 and 10.0 millimeters.
13.-A core covered with a sheath or cladding plastic, according to claim 12, CHARACTERIZED in that said wire has a diameter of 2.1 millimeters.
14.-A core covered with a plastic lining or coating, as any of claims 1 to 13, CHARACTERIZED in that the plastic coating with copper oxide nanoparticles has a thickness of 0.5 to 0.7 millimeters.
15.-A core coated with a plastic lining or coating, according to any of claims 10 to 14, CHARACTERIZED in that the wire with the plastic coating it has a diameter of between 2.6 and 3.8 millimeters.
16.-A core coated with a plastic lining or coating, according to any of claims 10 to 14 CHARACTERIZED because the metallic wire with the plastic coating it has a diameter of between 3.1 to 3.5 millimeters.
17.-A core coated with a plastic lining or coating, according to any of claims 1 to 9, CHARACTERIZED in that said core is made up of a plurality of wires.
18.-A core coated with a plastic lining or coating, according to any of claims 1 to 9, CHARACTERIZED in that said core is made up of a cable composed of a single strand which, in turn, is made up of a plurality of wires.
19.-A core covered with a plastic lining or coating, as any of claims 1 to 9, CHARACTERIZED in that said core is formed by a cable which, in turn, is formed by a plurality of strands which, in turn, are formed by a plurality of wires.
20.-A core covered with a plastic lining or coating, as any of claims 18 or 19, CHARACTERIZED in that said strands have a core made of fiberglass or the like.