JPH01120237A - Impounding material for aquaculture - Google Patents

Abstract

PURPOSE:To obtain the title impounding material which can elute antifouling ions into water for a long time by forming at least one of coating layers of a rubber containing antifouling metals on the fish nets. CONSTITUTION:Antifouling metals or an alloy thereof eluting antifouling ions such as copper, silver or mercury are mixed with a rubber as a base to prepare a coating material. Fish nets or metal nets are coated with the material to form one or more coating layers. The coating can reduce the deterioration of the nets.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a coating containing a metal such as copper or silver that releases ions having bactericidal and antialgal properties, or a compound containing this metal. The present invention relates to enclosure materials, and particularly to enclosure materials suitable for aquaculture fishing.

[Background of the invention]

It is well known that various metals act on the health and life support of living organisms, but recently the oligodynamic functions of specific metals have attracted attention. Here, oligodynamism refers to sterilizing, insecticidal, algae-preventing, and other effects that occur in minute amounts and cannot be chemically proven, and are effects that are only seen in very limited metals such as copper, silver, and mercury. refers to.

Oligodynamism will be specifically explained below using copper as an example.

The microbactericidal (algae-proofing) effect of copper was already known by some scholars in the 19th century, when it was confirmed that a small amount of copper ions killed the diatom Aomhidro. After that, various experiments were attempted, and for example, it was confirmed that the above-mentioned Aomhidoro can be killed by one molecule of copper ion.

In addition to the algae-preventing effect shown above, the eluted copper ions prevent the adhesion of barnacles, etc., and are effective in protecting various equipment such as pipes that are eroded into the sea, and in preventing red tide. It has also been found to be effective in suppressing the organisms that spawn.

[Conventional technology]

Focusing on the effects shown above, tests were conducted to utilize these metals in aquaculture fisheries.

For example, in aquaculture fisheries where fish are cultivated, a designated area of water is surrounded by a large cage made of m (hereinafter referred to as ``fish net'') or wire mesh, and fish are cultivated within this enclosure. There are the following problems that need to be solved.

First of all, over time, algae, barnacles, etc. adhere to the fish nets and cages that form the enclosure. As a result, these fish nets and cages become clogged, making it difficult for water to pass through, leading to rotting water in the enclosures and a lack of oxygen. Oxygen is also consumed by the adhering algae's own respiration, resulting in an oxygen shortage. As a result, fish and shellfish being cultivated are not only killed or weakened, but also become the cause of red tide. Furthermore, the red tide that occurs causes further damage to fish, creating a vicious cycle.

[Problem that the invention seeks to solve]

Therefore, in order to expect the above-mentioned effects of copper, a method of forming the cage from copper was tested.

That is, in this method, a cage is constructed from a wire mesh made of copper wire, and the cage is immersed in seawater to cultivate seafood. According to this method, it was possible to obtain very good results with almost no adhesion of Fujitbo or other preferable marine organisms or adhesion and growth of algae to the wire mesh, and a low mortality rate of fish. It was also found that when oyster shelves were formed using copper, there was less adhesion of algae, etc., and there was no negative effect on the oysters.On the contrary, it was found that oyster growth itself was promoted more than with conventional oyster shelves. .

However, while such good results can be obtained,
It was also found that after a few months, Fujitbo, algae, etc. began to rapidly attach, and the effect of copper almost disappeared. The reason for this is thought to be as follows. In other words, it is thought that copper ions eluted into the water are responsible for preventing the adhesion of Fujitbo and other algae, but as time passes, stable copper oxide forms on the surface of the copper. Since a film is formed and this film prevents the elution of copper ions, it is thought that the effect disappears after a certain period of time.

That is, there is a problem in the sustainability of the effect with the conventionally tested methods. In addition, the target product itself made of copper is expensive, making it quite uneconomical, and it has not yet been put into practical use. Furthermore, since copper wire, copper bars, etc. are used, the enclosure material has a fixed structure as a cage.
Unlike when using a fishing net, it was not possible to change the shape of the enclosure as appropriate.

[Means for solving the problem]- The present invention uses the above-mentioned ions such as copper, silver, mercury, etc. that prevent the adhesion of fujibo and have algae-proofing properties (hereinafter referred to as "antifouling ions"). Metals to be eluted (hereinafter referred to as "antifouling metals") or alloys containing these antifouling metals, and in some cases, both may be added to a base material such as rubber to form a coating material, such as mesh or wire mesh. etc. as the core material,
This is an enclosure material for aquaculture fisheries constructed by forming one or more layers of coating material on this core material.

[Effect]

Since we have formed one or more layers of coating material in which antifouling metals are added and kneaded to the materials constituting enclosure materials for aquaculture such as fish nets, antifouling ions can be removed from the coating material by immersing this enclosure material in water. is gradually eluted and exerts an antialgae effect. When the elution of ions decreases, the upper coating layer deteriorates and peels off or cracks, resulting in a new coating layer coming into contact with moisture, and ions are eluted from this new coating layer. As a result, the antifouling ions are eluted over a long period of time, and the effect is maintained for a long period of time.

〔Example〕

The present invention will be explained in detail below.

First, among the antifouling metals added to the base material of the film-forming material of the present invention, the effects of copper can be classified and displayed as shown in the table below. As mentioned above, there are other antifouling metals other than copper, but copper is preferred in consideration of the metal's price, safety, workability, etc.

Therefore, the antifouling property will be explained below using copper as an example.

Among the above-mentioned properties, the present invention particularly utilizes the antifouling properties of copper.

As an example of a copper-based metal, copper powder produced by an electrolytic method is as follows.

Electrolytic copper powder is copper powder with a purity of 99.5% or more, and its particle shape is dendritic as shown in Figures 1 and 3, and the powder has a large surface area, making it suitable for emitting ions. It also has excellent sinterability and compression resistance. Incidentally, the particle size distribution of the copper powder shown in Figure 1 is 145.200.250.
and 15 to 25% each in each mesh of 350,
Figure 3 shows particles whose particle size is smaller than this, and which accounts for 70% or more in 350 meshes. The powder shown in Figure 2 is sintered pulverized copper powder, but its shape is rounder than that of electrolytic copper powder.
It has a small specific surface area and is not very suitable for ion elution.

FIG. 4 shows a cross section of a braided cord constituting a fish net as an enclosing material. Reference numeral 1 indicates a core material of the braided cord, which is made of synthetic resin or the like. One or more layers of a coating material obtained by adding and kneading copper powder, which will be described later, are formed on this core material 1 . In the figure, reference numeral 2 is a first layer made of this coating material, 3 is a second layer, and 4 is a third layer, and the illustrated structure is formed from three coating layers.

FIG. 5 shows a configuration in which a fishing net is formed by knitting braided cords, and then the fishing net is immersed in a molten rubber bath C-pi to form a coating material on the surface of the fishing net. In this configuration, the coating is formed on the completed fishing net, so that the coating is formed to cover the entire knot 1a of each braided string.

Note that the reference numeral 5 indicates a coating. Since this configuration forms a coating on a completed net, it can also be applied to products currently on the market. Furthermore, the number of coating layers formed can be increased in accordance with the number of immersions into the molten rubber bath.

FIG. 6 shows another embodiment.

In this embodiment, the coating is formed on the braided string before forming the net, and the net is then knitted. Therefore, the entire knot 1a is not integrally covered with the coating, and the entire fishing net is covered with the coating. The coating surface can be enlarged.

If the core material 1 is made of copper wire instead of plastic, for example, the manufacturing cost will increase, but even if the coating is completely removed, copper ions can be further eluted.

By immersing the fish net with the above structure in water and partitioning off a predetermined underwater space, fish can be cultivated in the enclosure or used as part of an oyster rack or the like.

By immersing it in water, copper ions are first eluted from the copper powder mainly contained in the coating 4 of the third layer, thereby preventing the adhesion of algae and barnacles. Over time, this third
Layer 4 deteriorates, with cracks appearing on the surface and parts of it peeling off. As a result, copper ions are eluted from the copper powder contained in the second layer 3, which is the layer below it. By repeating such a process, it becomes possible to elute copper ions over an extremely long period of time, and high antifouling properties can be maintained for a long period of time. In addition, conventionally, when fishing nets were made of vegetable fibers such as hemp, there were problems such as the fibers corroding if left immersed in water for a long period of time. However, with the structure of the present invention, the surface of the string material is covered with a film, which prevents corrosion of the vegetable fibers for a long period of time, and has the secondary effect of extending the life of the fishing net. be able to.

Hereinafter, the coating material used for the above-mentioned fishing net will be explained in detail.

There are various types of coating materials that serve as the base material to which the antifouling metal is added and kneaded, but a rubber-based coating material will be explained below as an example.

(a) Base Silicone Rubber Silicone properties change little with temperature, and therefore silicone rubber also has much superior properties in terms of heat resistance, cold resistance, etc., compared to general organic rubbers. However, although the mechanical strength is relatively low, this is rather effective for elution of copper ions. In other words, if a net or wire mesh immersed in water is shaken by waves, etc., and the coating cracks due to this physical force, the contact area between the coating and water increases, and water is absorbed from that part into the underlying coating. Ions also become easier to elute from copper.

The physical properties of silicone rubber will be explained below.

(Heat resistance) The lifespan is almost infinite in an atmosphere of 150°C, and the heat resistance is extremely high.

(Cold resistance) Standard silicone rubber does not lose its flexibility up to -60°C. The embrittlement temperature is below -90°C. Therefore, this fishing net can be used under extremely wide conditions, and there is no risk that all the coating layers will peel off in a short period of time and the effectiveness of the copper will be lost.

(Chemical properties) Silicone rubber is chemically extremely stable because it has no unsaturation in its chemical structure. This property hardly deteriorates even if an antifouling metal is mixed.

In addition to the above rubber materials, styrene rubber (SBR), which is inexpensive and has good processability, may also be used, as well as nitrile rubber (NBR), chloroprene rubber (CR), acrylic rubber (AR), urethane rubber ( UR) etc. may be used depending on the usage conditions.

Note that the film-forming material is not limited to rubber; any material may be used as long as it can form a film on the string material and elute copper ions. Therefore, it is also possible to use materials that are classified as paints.

(b) Antifouling metallic material to be added to and kneaded in the base material and powder 11 The antifouling metallic material to be added was copper powder prepared by electrolytic method. Electrolytic copper powder is a copper powder with a purity of 99.5% or more, and its particle shape is dendritic, and the powder has a large surface area, making it suitable for emitting ions, and it also has good sinterability and compression resistance. Are better. Incidentally, the copper powder suitable for use has a particle size distribution of 15 to 25% in each mesh of 145, 200, 250 and 350, and is dispersed on average, or has a particle size smaller than this, It is appropriate that the ratio is 70% or more in 350 meshes.

Next, among the base rubber materials shown above, the inventor added and kneaded the electrolytic copper powder to silicone rubber to obtain a film forming material. Specifically, the electrolytic copper powder added had a particle size smaller than that shown in the figure, and the particle size distribution was 99.7% on a 350 mesh to form a film-forming material containing copper powder.

The amount of copper powder added was 30% by weight and 50% by weight based on the silicone rubber. Although the mechanical properties such as extensibility deteriorated with the addition of a large amount of 1i4 powder, the decrease in mechanical properties did not pose a problem in the case of the present invention, and ions were well eluted from the cracks that occurred. On the contrary, it is an advantage.

Furthermore, the dispersion of copper powder in silicone rubber is extremely good.
Even when confirmed under a microscope, no areas where the copper powder was unevenly distributed were found.

This is thought to be because the silicone rubber during kneading has a moderate viscosity, and the copper powder is small enough to be scraped, so that the effect of the difference in specific gravity between copper and silicone rubber is hardly noticeable. .

Although the present invention has been described above using a fishing net as an example, those skilled in the art can easily infer that the invention is not limited to fishing nets, and can also be implemented with cages formed of wire mesh or the like.

In addition to the above-mentioned antifouling metals, materials to be added to the film-forming material include ceramic powders that emit far infrared rays and the like, which may be added as appropriate depending on the purpose.

〔effect〕

As explained in detail above, the present invention is directed to metals such as copper, silver, and mercury that elute ions that prevent the adhesion of barnacles and have algae-proofing properties, or alloys containing these metals, and in some cases, to rubberize both. A coating material is formed by adding and kneading to a base material such as, and forming one or more layers of this coating material on a core material constituting an aquaculture enclosure material such as a rope or wire mesh. Since this is an enclosure material for aquaculture, it is possible to elute antifouling ions into the water over a long period of time, so there are no problems such as obstruction of water flow due to adhesion of barnacles, algae, etc., or a drop in oxygen levels in the water. , aquaculture can be carried out safely and effectively.

Furthermore, by covering the material that is to become the core material, deterioration of the core material can be reduced, and the life of the entire enclosure material can be extended.

[Brief explanation of the drawing]

Figures 1 and 3 are enlarged schematic diagrams of electrolytic W4 powder, Figure 2 is an enlarged schematic diagram of sintered and pulverized copper powder, Figure 4 is an enlarged sectional view of a fishing net according to the present invention, and Figure 5 is an enlarged schematic diagram of a fishing net. FIG. 6 is a partial view of a fishing net on which a coating has been formed by immersing it in a bath of molten coating material. FIG. 1... Core material 1a... Knot 2... Covering cylinder 11 3... Second coating layer 4... Third coating layer 5... Covering agent Patent attorney Kuwa Yoshizawa - Figure 1 Figure 2 50), Lm Figure 3 [m

Claims (4)

[Claims] (1) Enclosure materials for cultivating fish and shellfish by immersing them in water to form a certain enclosure, or for cultivating shellfish by holding shellfish, containing copper, silver, mercury, etc., barnacles, etc. Metals that elute ions that prevent the adhesion of algae and have anti-algae properties, or alloys containing these metals, and in some cases, both are added and kneaded to a base material such as rubber to form a coating material, such as a net or An enclosure material for aquaculture fisheries, characterized in that one or more layers of a coating made of this coating material are formed on the surface of a material constituting the aquaculture enclosure material such as a wire mesh. (2) The aquaculture fishery according to claim (1), characterized in that the base material of the film-forming material is rubber, and the film-forming material is made by adding and kneading copper powder to this rubber. Fencing material. (3) The aquaculture enclosure material according to claim 1, wherein the material constituting the aquaculture enclosure material is made of copper, and a coating is formed using this copper as a core material. (4) Claims characterized in that the enclosing material is formed by immersing a fishing net one or more times in a melting tank of a coating material to which copper powder has been added and kneaded to form a coating layer on the surface of the fishing net. The enclosure material for aquaculture fisheries described in paragraph (1).