JPS6197480A - Fibrous composite reduced in fouling of aquatic organism - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention provides fibers that reduce the adhesion of aquatic organisms to linear structures used underwater, especially in the ocean, such as ropes, nets, baskets, relatively thin rods, and grids. Concerning quality composites.

The composite of the present invention includes fixed nets, mooring ropes for fixed nets, mooring ropes for aquaculture and corners for aquaculture, ropes for aquaculture rafts,
Fishery materials such as seaweed cultivation nets, mooring ropes for floating structures such as floating docks, floating breakwaters, floating lighthouses, special work vessels moored for long periods, fixed cables for offshore oil drilling equipment, and seabed. It can be used as marine development materials such as rope cables for mining minerals, or as gratings and filter support parts to prevent foreign matter from entering water intake equipment for tanks that use seawater as cooling water.

<Conventional technology> For mooring ropes of fixed nets, straw or torn cloth is tightly wrapped around the rope, which is called weir-wrapping, and fixed using tar to prevent attachment of aquatic organisms. When the limit was reached, they were salvaged and removed.

With the recent development of hand-held grinders, it has become possible to scrape off the chips, so this practice has become less common. However, the grinding process is rough and is thought to significantly shorten the lifespan of the rope.

In order to prevent the adhesion of aquatic organisms, a method has been proposed in which metals that are toxic to aquatic organisms are twisted together in the form of wire or foil, but the metal in such replacement products is not easily exposed to water due to waves in the water. It has the disadvantage that it loses its effectiveness in a much shorter time than would be expected if it were to melt and lose weight at a constant rate because it is subjected to continuous stress, causing stress corrosion cracking and falling off. They are rated as extremely expensive as they lose their effectiveness long before the end of the cable or rope's lifespan.

In addition, methods of covering linear structures with plastic mixed with metals or their compounds that are toxic to aquatic organisms, and methods of attaching metals that are toxic to aquatic organisms to linear structures using adhesives were also considered. Plastics are inferior in light resistance and wave resistance to the metals and fibers that make up the structure, so the range of choices is limited, and to date no preferred material has been found.

Many paints containing toxic substances, such as ship bottom paint, are in practical use as materials that suppress the adhesion of aquatic organisms.

These paints exhibit excellent performance in the case of rigid structures such as ship bottoms and seawater intake ducts, but in the case of flexible linear structures, fatigue of the membrane occurs as it is bent by waves. It has the problem of falling off in a relatively short period of time. There is also the problem that the types of organisms that attach to the structure differ significantly depending on the shape of the structure, especially the curvature of the surface, with some organisms preferring to attach to flat surfaces such as the bottom of a ship, while others prefer to attach to thin ropes and nets. are generally not the same, and paints that are effective against one organism are often ineffective against the other, and prevention of aquatic organisms from adhering to linear structures used underwater has not reached a satisfactory level. .

<Problem to be solved by the invention> Linear structures used underwater, such as ropes, wires, cables, nets, baskets, lattices, thin rods, etc., have a large resistance due to the viscosity of water, despite their strength. When seaweed, shellfish such as Fujibbo, and other organisms grow and grow, their resistance becomes even greater, and as a result, they become unable to withstand the force and are destroyed.

To prevent this, regularly remove aquatic organisms or
It is necessary to prevent its formation. At present, there is no satisfactory method for preventing the attachment of aquatic organisms, and it is common practice to periodically remove them from the water and scrape them off.
The costs and losses associated with the suspension of operations are significant. Moreover, there is a problem in that the surface of the linear structure is inevitably slightly damaged by scraping off the attached organisms.

The present invention is a fibrous composite that reduces the adhesion of aquatic organisms, and when the metal that suppresses adhesion dissolves and loses its effect, only the coating material can be removed and replaced with a new one. characterized by something.

If the substance that suppresses the adhesion of aquatic organisms is a metal, it cannot be used if it is highly toxic to all living species, such as mercury or beryllium, because it is too dangerous and has too great an impact on the environment. Since weakly toxic metals may be completely ineffective against a specific group of biological species, it may be necessary to use multiple types of metals.

When using multiple types of metals, each metal has a different ionization tendency, resulting in a problem that the dissolution rate is significantly different than when using only one metal.

When coating a fibrous tape-like material or linear material with a thermally sprayed metal material as in the present invention, multiple types of metals are separately made by thermal spraying so that the metals do not come into direct contact with each other. By coating the linear structure in this manner, changes in the dissolution rate of the metal can be made so small that they do not pose a practical problem.

<Failure to solve the problem> Creating a part like a weir that can be thrown away together with attached organisms is certainly an effective method for maintenance of linear structures, but it does not allow organisms to penetrate inside. It needs to be wrapped very tightly. Therefore, it is extremely difficult to wrap it around partial linear structures such as nets and grids. In order to solve this problem, it is necessary to provide a function to prevent organisms from attaching to the parts that are discarded together with the organisms. When covering a linear structure with a material that has the function of preventing the attachment of organisms, it is not necessary to wrap it extremely tightly; the covering material can be wrapped in a tape and fixed by sewing or gluing. Alternatively, the covering structure may be formed by forming the material into a thread and using methods such as braiding.

Linear structures used underwater are susceptible to fatigue due to waves and deterioration due to sunlight, so there are strict requirements for covering materials. In order to prevent the coating material from falling off due to stress corrosion cracking due to fatigue caused by waves, it is considered necessary that the base material of the coating material and the components toxic to aquatic organisms are in close contact with each other. In the present invention, a fibrous tape or linear material is used as the base material, and a thermally sprayed metal or alloy material is used as the toxic component to aquatic organisms. Fibrous tape-like materials include woven or knitted fabrics, braided cords, non-woven fabrics, paper, or composites thereof, and filament materials include filaments, spun yarns, split yarns, twisted yarns, braided cords, or composites thereof. It is a thing. Although organic, inorganic, or metal fibers can be used as the fiber material, organic synthetic fibers are most preferred due to their durability. Copper, tin, zinc, chromium, manganese, molybdenum, nickel, lead, antimony, bismuth, etc. are used as toxic metals. Highly toxic metals are alloyed with less toxic metals,
Use by covering with a plastic film to suppress elution.

If even weakly toxic metals elute into seawater too quickly, the elution should be suppressed. A method of forming a battery by contacting different metals is also effective in suppressing or promoting elution.

The reason why metals with toxic components are made into thermal spray moldings is that thermal spray moldings have edges that resemble stacked roof tiles, are more porous and have a larger surface area than wire rods or foils, and inherently have a higher elution rate. In addition, it is easy to suppress extrusion by co-melting plastics and ceramics, it has good adhesion by intertwining with fibrous tape-like materials and linear materials at the interface, and it has a high molding speed. , the molding cost per metal weight is lower than that of plating or vapor deposition.

In order to prevent toxic components from falling off or leaching from the metal base material, it is effective to apply synthetic resin, tar, pitch, or a mixture thereof before, after, or at the same time as coating the linear structure. Synthetic resins include polyurethane, polyacrylamide, silicone, epoxy,
Resins such as polyvinyl alcohol, acrylic acid, acrylic ester, and maleic acid can be used. It is preferable to use these as a copolymer, and it is also preferable to use them colored in a dark color such as black.

The thermal spraying method of the present invention can be any conventionally known method; however, a thermal spraying method in which a powdered thermal spray material is introduced into a flame or plasma jet, and a flame or arc discharge method can be used. A preferred method for producing the fibrous composite of the present invention is to introduce a rod-shaped thermal spray material into the material, crush it, melt it, and then thermally spray it.

Metals or alloys that are thermal spray materials are in the form of fine particles that are carried by a plasma stream or high-temperature air current, and the whole particles, the surface layer of the particles, or their binder components are melted and accelerated to near-sonic or supersonic speeds, forming a fibrous sheet. Collision with an object or linear object.

Some of the particles rebound elastically and scatter, but most of the particles are pressed onto the fiber surface by their own momentum and form a film, which accumulates and becomes entangled, and some of them fuse together. to form a spray molded product. Some of the particles penetrate and stick to the fiber surface, and some penetrate deeply through the gaps between the fibers and fuse with subsequent particles to form a network structure. The particles pressed onto the surface of the organic fiber soften and melt the area near the surface of the organic fiber due to the amount of heat they possess, but the melted particles are sufficiently small compared to the thickness of the fiber and the fiber is cooled at a sufficient rate. In the case where the fibers are heated, it is possible to form a thermally sprayed molded product without softening the core of the fibers. Thermal spray moldings can be made into continuous films, intermittent films, or layered films by selecting the spraying conditions. A sintered or sponge-like molded product can be obtained.

Even when the fibrous sheet or linear material is not an organic fiber, if it is a heat-meltable fiber, a thermal spray molded product is formed using the same mechanism as that for organic fibers. Even in the case of infusible fibers, the only difference seems to be that the particles do not pierce the fibers.

The plasma or high temperature gas used for thermal spraying is 6000°C.
However, by shortening the contact time and cooling quickly after contact, it is possible to reduce the temperature of the plasma or high temperature. Deterioration due to gas can be reduced to a substantially negligible level.

<Function> The present invention is applicable to ropes, cables, nets, grids,
Directly coating linear structures such as cages and thin rods with metals or alloys that are toxic to aquatic organisms; adhering such metals or alloys to fibrous tape-like or linear objects by thermal spraying; , the main purpose is to coat linear structures with this. One of the features of the present invention is that when the coating loses its ability to inhibit the attachment of aquatic organisms, it can be removed and easily recoated. Second, it is possible to coat different metal materials separately, and there is little electrochemical increase or decrease in elution rate due to contact of different metals. Thirdly, since it is possible to coat with metal on the inside, even if it falls off due to waves, it remains attached to the linear structure and does not lose its ability to prevent attachment of aquatic organisms.

Example 1 Vinylon spun yarn fabric (plain weave, basis weight 110'/nt
) was thermally sprayed with copper using an oxyacetylene flame spray gun. The amount of thermal spraying was 120')/,,(.This cloth was slit into medium 20M1L pieces and wrapped around a vinylon spun yarn rope with a diameter of about 22N+.The wrapped tape was fixed using sewing and epoxy resin. Coated ropes were made with a wrapping amount of 169% 32q and 64Q per meter of rope, and were thrown into the Seto Inland Sea to examine the adhesion of organisms.The adhesion rate showed that the covered rope was covered with marine organisms. The area ratio was adopted.

As a comparative example, the adhesion rates were determined for a rope that was not coated and a rope that had 0.5 strands of copper wire twisted into it.

The results are shown in Table 1. In the case of copper wire, the effect of suppressing the adhesion of marine organisms is not proportional to the amount of twisting. This seems to be because disconnection due to fatigue rather than wear due to elution determines the lifetime of the adhesion suppressing effect.

Table 1 Example 2 Woven fabric of polyester and vinylon blend yarn (blend ratio 50:5
An alloy of 87% zinc and 13% aluminum was thermally sprayed onto the material (plain weave, fabric weight: 95'/d) using an arc spray gun. The amount of thermal spray was 135 Qshio.

This cloth was slit and a tape was applied to cover a part of a stationary net (the rope making up the net had a diameter of approximately 711 m), which was then thrown into the sea to examine the attachment of organisms. As a covering method, we adopted a method of sewing it into a tube shape and a method of making a tube with a knitted structure. Tar was used to fix the coating. The area used for the test was approximately 1 meter deep.

As a comparative example, the adhesion rate of the uncoated portion was determined. The results are shown in Table 2.

Table 2 Example 3 Copper-sprayed vinylon cloth similar to that used in Example 1 was wrapped around a wire rope (made of steel) used under the sea.
They were put into the sea and examined to see if any organisms were attached to them.

As a comparative example, a wire rope directly sprayed with copper was used.

The effect of preventing the adhesion of marine organisms was not significantly different between the present invention and the comparative example, and both were judged to be effective.However, in the case of the comparative example, severe iron rust was observed about a week after the injection, and the thermal spray molded copper It was found that the defective parts significantly accelerated corrosion.

In the case of the present invention, rusting occurs on the entire surface of the wire rope, and the rusting progresses not so quickly, and even after about 12 months, the initial strength is 8.
Although the comparative example had a coefficient of 0 or more, the strength was locally lost.

Example 4 Molybdenum was thermally sprayed onto the same vinylon cloth as in Example 1 using a plasma spray system 7M manufactured by METOCO, USA.

When this molybdenum sprayed cloth was used in place of the copper sprayed cloth of Example 1, it was found that it similarly had an excellent effect of preventing the adhesion of underwater organisms.

Example 5 Instead of the zinc and aluminum alloy sprayed cloth of Example 2, cloths were made by spraying pure zinc, tin, lead, lead-containing zinc, cadmium-containing zinc, bismuth-containing zinc, and antimony-containing zinc by an arc method, and each When we investigated the effect of preventing the adhesion of organisms in water, we found that it had the same excellent effect as zinc and aluminum alloys.

Example 6 Instead of the copper sprayed cloth of Example 1, we made cloths that were sprayed with nickel, chromium, and manganese by the oxyacetylene flame method, and examined the effectiveness of each of them in preventing the adhesion of organisms in water. It was found to be effective.

Claims (1)

[Claims] A linear structure used underwater is coated with a fibrous tape or linear material sprayed with a metal or alloy that is toxic to aquatic organisms, reducing the adhesion of aquatic organisms. fibrous composite