JPH04270769A - Antifouling composition for fishing net - Google Patents

Abstract

PURPOSE:To provide the subject composition composed of powdery copper alloy containing specific amounts of zinc, etc., and lead, a spreading agent and a solvent, useful for the treatment of fishing net and capable of protecting the net from the adhesion of marine life over a long period. CONSTITUTION:The objective composition is produced by compounding (A) preferably 10-35 pts.wt. (based on 100 pts.wt. of the composition) of a powdery copper alloy containing (i) 6-50wt.% of zinc and/or magnesium and (ii) 0.01-5wt.% of lead, (B) a spreading agent (preferably rosin, coumarone resin, etc.), (C) a solvent for dissolving the spreading agent (e.g. xylene or toluene) and (D) other additives such as filler and dispersing agent.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antifouling composition for fishing nets that prevents the adhesion of marine organisms and seaweed.

0002

[Prior Art] Because stationary nets and aquaculture nets are placed in seawater for long periods of time, diatoms, barnacles, sea squirts, green algae, oysters, bivalves, etc. are deposited on these stationary nets and aquaculture nets during the underwater immersion period. Over time, they can get stuck and block the mesh of the net, obstructing the flow of seawater and having a negative impact on the growth of farmed fish.Furthermore, the weight of the net increases due to the deposits, which increases wave resistance during typhoons. In some cases, the net may be damaged or washed away. Therefore, compositions to prevent marine organisms from adhering to these fishing nets are used, and although various antifouling active ingredients have been proposed in the past, copper compounds and organic compounds are generally used. has been done. Particularly effective among these compounds are organic tin compounds, such as tributyltin oxide, which has been widely used because of its bactericidal and antibacterial effects. However, because it is highly toxic and difficult to decompose,
Recently, it has been discussed as a social issue due to its environmental pollution, and voluntary measures have been taken to completely ban its use.

0003

[Problems to be Solved by the Invention] In order to solve the problems of the prior art as described above, the present inventors first prepared a mixture of fine particulate metallic copper and a rosin-based resin or a coumaron-based resin into a cellulose-based polymer material. proposed an antifouling composition for fishing nets which is dispersed in a spreading agent (see Japanese Patent Publication No. 6661/1983). This composition is not toxic like organic tin compounds and has excellent antifouling properties against marine organisms and seaweed, but it is used in the sea areas (warm sea areas, stagnant waters in deep bays, etc.)
It was found that the antifouling effect was reduced by

0004

[Means for Solving the Problems] In view of the above-mentioned circumstances, the present inventors conducted various studies and conducted underwater immersion tests on antifouling compositions containing various copper alloy powders. The present inventors have succeeded in obtaining an antifouling composition for fishing nets containing copper alloy powder that has a high effect of preventing the adhesion of . That is, the fishing net antifouling composition of the present invention contains copper alloy powder as an active ingredient containing 6 to 50% by weight of at least one metal selected from zinc and magnesium and 0.01 to 5% by weight of lead; It consists of a spreading agent and a solvent.

[0005] The copper alloy powder as an active ingredient used in the fishing net antifouling composition of the present invention has the above composition, and contains zinc and magnesium contained in the copper alloy. The content of at least one metal is 6
If it is less than % by weight, the chemical reaction between the copper alloy powder and various ions in the seawater, especially chlorine ions, etc. will not proceed smoothly, and the elution of copper ions will be excessive, resulting in the antifouling effect not lasting for a long time. . On the other hand, if the content exceeds 50% by weight, the total copper content will decrease, and the amount of copper ions eluted will decrease, resulting in poor antifouling effect.

[0006] Furthermore, the content of lead contained in the copper alloy is 0.
．． When the amount is less than 0.01% by weight, the antifouling performance decreases, according to the results of an underwater immersion test. This is considered to be because the scale-like copper alloy powder with high antifouling effect was not produced. On the other hand, if the content exceeds 5% by weight, the specific gravity per unit volume of the copper alloy powder becomes large, and the fishing net antifouling composition has a high sedimentation property and lacks stability during storage.

[0007] The copper alloy powder used in the composition of the present invention is a copper alloy powder containing the above-mentioned components, and includes, for example, foundry brass alloy ingots as designated by JIS,
High-strength brass alloy ingots for casting, magnesium copper ingots, and copper products manufactured from these materials (various brass, red bronze),
Examples include, but are not limited to, powders of brass castings and the like. As the copper alloy powder, preferably used is a copper alloy powder processed into a fine powder of 200 mesh or less (short fibrous, granular, or flaky), but especially a flaky copper alloy whose surface is not oxidized. Powder is preferred.

[0008] The content of the copper alloy powder as an active ingredient in the composition of the present invention can be arbitrarily changed according to the required performance and price of the fishing net antifouling composition and is not particularly limited. However, it is usually preferably 5 to 40 parts by weight, particularly preferably 10 to 35 parts by weight, per 100 parts by weight of the composition of the present invention.

The fishing net antifouling composition of the present invention may contain known antifouling active ingredients as an optional ingredient in addition to the above-mentioned essential active ingredients. The blending amount can be made small. In addition, in producing the fishing net antifouling composition of the present invention, copper alloy powder, which is an active ingredient of the present invention, a spreading agent, and a solvent are kneaded by a normal paint manufacturing method using a ball mill or the like. Alternatively, if necessary, these may be dispersed and kneaded together with pigments, fillers, stabilizers, dispersants, etc. Note that the spreading agent and the solvent may be mixed in advance to form a spreading agent solution, and this spreading agent solution and the copper alloy powder may be kneaded.

[0010] The spreading agent used in the fishing net antifouling composition of the present invention includes natural resins, oily resins, synthetic resins, etc., but preferably rosin resins, coumaron resins,
Examples include vinyl resin, chlorinated rubber, and various cellulose polymers. Further, examples of the solvent for dissolving the spreading agent include xylene, toluene, dimethylformamide, and the like. The produced fishing net antifouling composition is usually spread by a dipping method, but it can also be spread by a method suitable for the object.

[0011]

[Action] The fishing net antifouling composition of the present invention can be applied by spray coating,
It can be used by coating fishing nets with the usual methods such as brushing, pouring, and pouring. On the surface of the fishing net obtained in this way, copper ions are eluted from the coated fishing net antifouling composition into the sea that comes into contact with the fishing net over a long period of time, thereby preventing the adhesion and growth of marine organisms. In this case, first, a spreading agent, such as a mixture of rosin and ethyl cellulose, is gradually dissolved by the slightly alkaline nature of seawater.
When the surface of copper alloy powder comes into contact with seawater, copper ions are generated,
By killing the larvae of marine organisms, this copper ion can prevent contamination of fishing nets for a long period of time.

[0012] Conventional pure metallic copper powders have been able to provide antifouling effects only for a short period of time due to the delay in the initial generation of copper ions and the generation of a large amount of copper ions at once. In the present invention, copper alloy powder containing zinc, magnesium, and lead, which are metals with a greater tendency to ionize than copper, is used, so the amount of copper ions leached into the sea is controlled and remains constant throughout the period. It has an antifouling effect and allows fishing nets to be immersed in the sea for a long period of time.

[0013]

[Example] Fishing net antifouling compositions (Nos. 1 to 6) were produced by the above method using the compositions of the formulation examples shown in Table 1 below (units in Table 1 are weight %). The species of attached organisms and attached area of the fishing net coated with the composition were investigated after 7 months, and the results are shown in Table 2 below. Also,
The change in the weight of biofouling was also investigated, and the results are shown in Table 3 below. For comparison, the same was true for compositions (No. 7 to 13) having compositions outside the scope of the present invention shown in Table 1 below, commercially available antifouling agents (A, B), and control group (untreated product). The results are shown in Tables 2 and 3 below. Table 1 below also shows the storage stability of each composition after 12 months.

[0014] The test method for the adherent species and adherent area at the 7th month shown in Table 2 below is as follows. That is, first, a polyethylene knotless fishing net (60
I used verse 6 from the book. Size is 400mm x 40
(0 mm square) was immersed in the composition shown in Table 1 below for 10 minutes and then air-dried for 24 hours. Commercially available products were also operated in the same manner. Next, the treated fishing nets were attached to a bent 600 mm x 600 mm steel outer frame with a diameter of 8 mm, and were placed under seawater at a depth of 1.5 meters from April 1, 1990 to October 31, 1990, 500 meters off the coast of Kii-Nagashima-cho, Mie Prefecture. 5-2.0
It was suspended at a position of m and the degree of adhesion of marine organisms and seaweed was investigated on the last day of every month for 7 months. Note that in Table 2 below, the condition observation at the 7th month (last month) is recorded. The antifouling effect in Table 2 below is determined based on the area of adhesion by marine organisms (the control area is
).

[0015] Regarding the change in the weight of biofouling shown in Table 3 below, the test net was taken out of the seawater, removed from the suspension rope frame, the weight of the net at the edge was measured, and the net weight was determined from the wet weight of the net. The weight of the deposit was calculated by subtracting the original weight of the sample, and the values are shown in Table 3.

[0016]

[Table 1]

[0017]

[Table 2]

[0018]

[Table 3] As is clear from the results shown in Table 2 above, as a result of investigating nine representative types of sessile organisms, the results of the study of the present invention (N
o. In Nos. 1 to 6), there was less adhesion of slime etc. seen in Comparative Examples (Nos. 7 to 13). Furthermore, as can be seen from the results in Table 3 above, in the examples of the present invention, there is almost no increase in weight from the 6th month onwards. Thus, it was found that the fishing net antifouling composition of the present invention exerts an excellent antifouling effect on fishing nets for a long period of time.

[0019]

[Effects of the Invention] The fishing net antifouling composition of the present invention, which is a mixture of a specific copper alloy powder, a spreading agent, and a solvent, exhibits an excellent antifouling effect on fishing nets. Fishing nets are protected from contamination by marine life over a long period of time.

Claims (1)

[Claims] Claim 1: Consists of a copper alloy powder as an active ingredient containing 6 to 50% by weight of at least one metal selected from zinc and magnesium and 0.01 to 5% by weight of lead, a spreading agent, and a solvent. Fishing net antifouling composition.