JPH0837997A - Antifouling fishing net for culturing fish or shellfish and method for preventing fishing net for fish or shellfish from fouling - Google Patents

Abstract

PURPOSE:To obtain an antifouling fishing net for culturing fishes or shellfishes, not having toxicity, not eluted in water, free from the care of marine pollution, and persisting the antifouling property. CONSTITUTION:A water-repelling film 3 comprising a powdery material (preferably inorganic particles or organic particles such as fluororesin particles or silicone resin particles) and a hydrophobic resin (preferably a fluororesin, a silicone resin, a polyethersulfone resin, polyphenylenesulfide resin, an acrylic resin, an epoxy resin or a polyimide resin) is formed on the surface 2 of a fishing net to dispose fine uneven structures 6, 7 capable of holding air on the net surface 2. The uneven structures 6, 7 preferably have distances (s) of 0.3-100mum between the projections 7, and have h/s rations of 0.3-3 between the heights (h) of the projections 7 and the distance (s).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fishing net for aquaculture, which is excellent in antifouling property and durability of antifouling performance, and an antifouling method for a fishing net for aquaculture.

[0002]

2. Description of the Related Art Generally, a fishing net used for aquaculture of seafood in a state of being immersed in water causes clogging of the net when aquatic organisms such as algae and shellfish adhere to the surface and stain the surface.
For example, the cage will become oxygen deficient, which will damage the seafood and lead to environmental deterioration.

Therefore, conventionally, it has been known to apply a toxic anti-fouling agent for fishing nets to the surface of the nets of the fishing net for the purpose of imparting the performance of preventing the attachment of aquatic organisms to the fishing net for aquaculture. As another method, the antifouling property has been improved by applying a fluorine-based or silicone-based synthetic resin coating having excellent adhesion and release properties onto the surface of the net thread of the fishing net.

[0004]

However, the above-mentioned prior art has a problem that when the anti-fouling agent for fishing net is used, it causes toxicity due to its own toxicity, which causes contamination of seafood to be cultivated. . Further, when a fluorine-based or silicone-based synthetic resin coating is used, although the effect of improving the antifouling property is initially observed, not only the improving effect is insufficient, but also the antifouling property is improved in a short period of time. Since the stain resistance is lowered, there is a problem that durability of antifouling performance is poor.

Therefore, the present invention solves such a problem, and an object of the invention is to prevent fishnet aquaculture nets and fishnet aquaculture nets excellent in antifouling property and sustainability of antifouling performance. To provide a dirty method.

[0006]

[Means for Solving the Problems]

1. The fishing net for antifouling seafood culture of the present invention is a net having a water-repellent film made of a mixture of a powder and a hydrophobic resin on the surface of the net of the fishing net, and fine irregularities capable of retaining air on the surface of the net. It is characterized by having a structure. 2. Further, the powder is selected from inorganic particles, fluororesin particles, silicone resin particles, and other organic particles 1
It is characterized in that it is composed of two or more species.

3. Further, the hydrophobic resin is made of one or more selected from the group consisting of fluororesin, silicone resin, polyether sulfone resin, polyphenylene sulfide resin, acrylic resin, epoxy resin, and polyimide resin. . 4. Furthermore, the fine uneven structure has a space s between the convex portions of 0.
It is characterized in that it is 3 to 100 μm, and the ratio h / s of the height h of the convex portion and the interval s is in the range of 0.3 to 3.

5. The antifouling method of a fishing net for seafood culture of the present invention comprises forming a water-repellent film made of a mixture of a powder and a hydrophobic resin on the surface of the net of the fishing net, and allowing the surface of the net to have fine air retention. A feature is that an uneven structure is provided. 6. A water-repellent film made of a mixture of a powder and a hydrophobic resin is formed on the surface of the net of the fishing net, and the anti-fouling fish net aquaculture net having a fine uneven structure capable of retaining air on the surface of the net is provided. The feature is that the antifouling property is maintained by supplying air from the deep part of the water and holding and renewing the air film on the surface of the mesh yarn.

In the present invention, an air film is formed on the surface of the net of the fishing net as described above so that the surface of the net of the fishing net for aquaculture (hereinafter abbreviated as a fishing net) has an uneven structure. To prevent the adherence of. Hereinafter, the configuration of the present invention will be described in detail. The fishing net used in the present invention is, for example,
A multifilament or monofilament made of a synthetic resin such as polyethylene, polyester, or polyamide is used as a raw yarn to be twisted into a net yarn, which is then knitted.

In the present invention, a mixture of powder and hydrophobic resin is applied to the surface of the net yarn of this fishing net so that the interval s between the convex portions is 0.3 to 100 μm and the height h of the convex portions is h. And the interval s
To form a water-repellent film having on its surface an uneven structure having a ratio h / s of 0.3 to 3. The spacing s between the convex portions is 10
When it is larger than 0 μm, the air film formed on the surface becomes thick, but it tends to be peeled off due to disturbance such as water flow. On the other hand, when the space s is smaller than 0.3 μm, the amount of air that can be held in the recesses on the surface is small and the air film becomes thin, which makes it difficult to stably hold air for a long period of time. The powder should be hydrophobic. Examples of the powder include hydrophobic silica particles and polytetrafluoroethylene particles. At least one of these may be used. When inorganic particles are used, it is preferable to use water-repellent particles with a surface treatment agent such as perfluoroalkylsilane.

The hydrophobic resin is non-toxic to seafood and has a contact angle with water of 90 ° or more, particularly 110 °.
The above is better. For example, fluorine resin, silicone resin, polyether sulfone resin, polyphenylene sulfide resin, acrylic resin, epoxy resin, polyimide resin and the like. At least one of these may be used.

Since the fishing net of the present invention thus constructed has a fine uneven structure on the surface of the net yarn, air is taken into the recesses in water and an air film is formed there. This action will be described with reference to FIGS. 1 and 2. FIG. 1 is an enlarged cross-sectional view showing a surface structure of a net yarn of a fishing net of the present invention, and FIG. 2 is an enlarged cross-sectional view for explaining a state where a surface of a water-repellent film body holds air. In the figure, 2 is the surface of the net yarn, 3 is a film body, 6 is a concave portion, and 7 is a convex portion. 1 and 2, the illustration of the water-repellent fine particles used for imparting fine irregularities to the surface of the film body is omitted.

In FIG. 1, the film body 3 applied to the surface 2 of the mesh has a concavo-convex structure composed of fine concave portions 6 and convex portions 7 on the surface thereof. The interval s between the convex portions 7 is 0.3
˜100 μm, and the ratio h / s between the height h and the interval s is in the range of 0.3 to 3. Since the film body 3 itself is made of a water-repellent material and has the fine concavo-convex structure as described above, as shown in FIG. Will be trapped.

In practice, since such a film body 3 is formed on land, as shown in FIG. 2, when the surface of the film body 3 is immersed in the water 10, the flooded position of the recess 6 is reached. Since the water pressure P at and the surface tension of water are in an equilibrium state, the air a is held in the concave portion 6 and a thin air film is stably formed on the surface of the film body 3, so that the underwater organisms are formed by this air film. It becomes impossible or difficult to adhere to the surface of the film body 3, and effective antifouling property can be achieved.

By forming the film body 3 into a multi-layer structure comprising a first film body as an anchor layer containing relatively large particles and a second film body as a surface layer containing water-repellent fine particles. The adhesiveness of the film body 3 to the net yarn surface 2 is improved, and the reliability of the antifouling property improving effect can be further enhanced. In this way, the surface of the net yarn of the fishing net is formed of a non-toxic water-repellent material, and by forming a film body having a fine uneven structure on the surface, effectively preventing the attachment of aquatic organisms, Although the fishing net of the present invention having improved antifouling property can be obtained, when the fishing net is put to practical use, by supplying a small amount of air continuously or intermittently from several places under the fishing net, The effect of preventing adhesion of aquatic organisms can be further improved, and the antifouling property can be maintained and improved. That is, it is possible to maintain the antifouling property by supplying air to the fishing net from deep inside the water and maintaining and renewing the air film on the surface of the net yarn.

This operation will be described with reference to FIG. FIG. 3 is an enlarged cross-sectional view showing an air layer formed on the surface of the film body. In FIG. 3, when the air a is held in the concave portion 6 of the film body 3 and new air b is further supplied in the vicinity thereof, the air b easily interacts with the air a due to the surface energy reducing action. And a thin air film 8 is formed on the surface of the film body 3 to form a three-layer structure of the surface of the film body 3, the air film 8 and the water 10.

That is, on the surface of the film body forming the air film 8, when new air b is supplied from the outside, the air a already attached and existing on the surface serves as a nucleus, which becomes the new air b. It has the property of taking in and spreading it around. Therefore, the air supplied from the lower part of the fishing net thickens the air film 8 attached to the film body 3 on the net yarn surface 2 of the fishing net, and forms a film-like flow upward due to the influence of buoyancy.

As described above, when the air film 8 attached to the film body 3 on the net yarn surface 2 becomes thicker, it becomes more difficult for aquatic organisms to approach the surface of the film body 3, and as a result, the film body 3 becomes The effect of preventing biofouling on the surface is further improved. In addition, the supply of new air b thickens the air film 8 formed on the film body 3 on the surface 2 of the mesh yarn, so that the chance of the surface of the film body 3 coming into contact with seawater is reduced and the surface is prevented from being soiled. Therefore, it has the effect of improving the durability of the air film forming ability on the surface of the film body 3.

As described above, the antifouling net for aquaculture of seafood of the present invention is extremely excellent in antifouling property. Hereinafter, the configuration and effects of the present invention will be described in more detail with reference to examples.

[0020]

EXAMPLES In order to demonstrate the effect of the present invention, an experiment of submersion of a surface-fouling-treated fishing net for seafood culture in the sea using the apparatus shown in FIG. 4 was carried out simultaneously for two cases of air supply and non-supply. Carried out. In this experiment, the size is 1m x 1m square,
A nylon fishing net having a mesh size of about 3 cm square and a net thickness of about 2 mm was used.

[0021] To coat the net yarn of the fishing net, an epoxy resin containing 20% of glass beads having an average particle diameter of 43 µm was brush-coated as a base to form a macro uneven structure on the surface of the net yarn. Next, a fluorine-based coating agent and an average particle size of 4μ
The polytetrafluoroethylene particles of m were mixed at a ratio of 80% with respect to the solid content of the coating agent, butyl acetate was appropriately added, and the dispersion was sufficiently stirred, brushed on the surface to be coated with the undercoat, and dried at room temperature.

When the fishing net surface-treated in this manner was immersed in water, it was observed that an air film was formed on the entire surface of the fishing net in any posture. Then, when air was injected into the surface of this fishing net with an injection needle, it was observed that the air became bubbles and was taken into the air film without floating. Since this fishing net holds air not only on the surface of the net thread but also inside the net thread, it has a large buoyancy and does not sink into the water.

In the test apparatus shown in FIG. 4, the fishing net 20 used for the submersion experiment is fixed to the rust-prevented fishing net fixing pipe frame 21, and an air supply system for supplying air is added. The air supply system causes the air compressed by the compressor 22 to flow into a vinyl chloride pipe 25 having an outer diameter of 26 mm attached to the lower portion of the fishing net 20 via a flow rate adjusting needle valve 23 and a flow meter 24,
The pipes 25 were distributed to the ten air supply nozzles 26 arranged at equal intervals in the longitudinal direction of the pipe 25 and supplied to the surface of the net yarn of the fishing net.

The air supply nozzle 26 has a length of 15 m.
A polytetrafluoroethylene tube having a diameter of m, an inner diameter of 0.5 mm and an outer diameter of 1.5 mm was used. In the underwater immersion experiment, the pipe frame 21 to which the fishing net was fixed was vertically sunk from the raft so that the upper end of the fishing net was 30 cm above the water surface, and the state of adherence of aquatic organisms to the fishing net was regularly observed visually. The amount of air supplied when supplying air is 200 cc /
Minutes and continuously supplied.

For comparison, an experiment was also conducted on a non-surface-treated fishing net. These experiments were conducted from May to October on the coast of Tamano City, Okayama Prefecture.
Table 1 shows the evaluation results of the aquatic organism attachment status of the fishing net.

[0026]

[Table 1] As is clear from the results in Table 1, the non-surface treated fishing net
After 3 months of immersion, clogging occurred due to the adhesion of algae. On the other hand, in the case of the surface-treated fishing net, when no air was supplied, slime adhered to the lower part of the fishing net 2 months after immersion, and after 6 months, clogging due to algae adhesion was partially observed. However, in the case of air supply, no change was seen on the surface of the fishing net until 3 months after immersion, and even after 6 months, algae were slightly attached around the mesh intersection. According to the fishing net and the antifouling method of the present invention, it was confirmed that the antifouling property is extremely excellent and the period until clogging due to algae, shellfish and the like can be significantly extended.

[0027]

As described above, according to the fishing net for fish culture and the antifouling method of the fishing net for fish culture of the present invention, the material (powder, resin) used is not toxic and is eluted in water. Since it does not occur, there is no fear of marine pollution and no harmful substances are accumulated in the body of seafood, so it can be safely used for aquaculture. Further, the antifouling property can be maintained for a long period of time, and particularly by supplying a small amount of air from the lower part of the fishing net, the duration of the antifouling property can be dramatically extended. In addition, since the air film-forming paint (mixture of powder and resin) has excellent mold releasability, even if aquatic organisms attach to the fishing net, the attachment is not strong, and they drop off due to tidal currents and waves. Cheap.

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional view showing a surface structure of a net yarn of a fishing net of the present invention.

FIG. 2 is an enlarged cross-sectional view for explaining a state in which the surface of the film body holds air.

FIG. 3 is an enlarged cross-sectional view showing an air layer formed on the surface of the film body.

FIG. 4 is a schematic diagram of a test apparatus used in Examples.

[Explanation of symbols]

2 Net surface of fishing net 3 Membrane 6 Concave 7 Convex 8 Air film 10 Water 20 Fishing net 21 Fishing net fixing pipe frame a Air 22 Compressor 23 Needle valve 24 Flowmeter 25 Vinyl chloride pipe 26 Air supply nozzle

Claims (6)

[Claims] 1. A water-repellent film made of a mixture of a powder and a hydrophobic resin is formed on the surface of a net of a fishing net, and the net has a fine concavo-convex structure capable of retaining air. Antifouling fishnet fishing net. 2. The antifouling seafood culture according to claim 1, wherein the powder comprises one kind or two or more kinds selected from inorganic particles, fluororesin particles, silicone resin particles, and other organic particles. Fishing net. 3. The hydrophobic resin comprises one or more selected from the group consisting of fluororesin, silicone resin, polyether sulfone resin, polyphenylene sulfide resin, acrylic resin, epoxy resin and polyimide resin. The antifouling fish and shellfish aquaculture net according to 1. 4. The fine concavo-convex structure has a space s between the protrusions of 0.3 to 100 μm, a height h of the protrusions and the space s.
The anti-fouling fish and shellfish aquaculture net according to claim 1, having a ratio h / s of 0.3 to 3. 5. A water-repellent film made of a mixture of a powder and a hydrophobic resin is formed on the surface of a net of a fishing net, and a fine uneven structure capable of retaining air is provided on the surface of the net. Antifouling method of antifouling fishing net for aquaculture. 6. An antifouling seafood having a fine concavo-convex structure capable of retaining air on the surface of a net formed with a water-repellent film made of a mixture of powder and a hydrophobic resin on the surface of the net. A method for using an antifouling fish and shellfish aquaculture net that maintains antifouling properties by supplying air to the aquaculture net from deep inside the water to maintain and renew the air film on the surface of the net yarn.