JPH089855B2 - Surface structure to prevent adhesion of marine organisms - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a structure in which marine life is applied to a structure that operates in contact with seawater, such as an outer surface of a steel pipe used for an oil drilling rig, an inner surface of a seawater pipe, and a ship bottom. The present invention relates to a surface structure that prevents adhesion.

[Conventional technology]

A method that has been widely adopted as a means for preventing the adhesion of marine organisms such as barnacles and mussels is to apply a coating material containing an antifouling agent such as an organic tin compound or cuprous oxide.

[Problems to be Solved by the Invention] However, in such a conventional method, not only is the marine pollution due to the antifouling agent in the paint regarded as a problem, but the effective period is 2 to
Up to 3 years.

As an alternative to such an antifouling agent, coating with a copper-based metal or coating of a low surface energy type paint with a silicon resin or the like has begun to be adopted. However, these also have limitations such as exhaustion or short useful life.

As another method, a large number of fine hair fibers are planted on the surface located in the sea and the biological adhesion is prevented by rocking the fine hair fibers in the sea. It is disclosed in Sho 60-159044. However, according to the experiments conducted by the present inventors, in the case of a fine fiber having a sufficient oscillating property, the deformation and damage of the fiber or the entanglement of the fibers are likely to occur in a relatively short period of time, and as a result, the initial oscillating property is impaired. It has been found that there is a problem that the effect of preventing biofouling is reduced.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a surface structure for preventing adhesion of marine organisms, which is effective for a long period of time without causing marine environmental pollution.

[Means for solving problems]

As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that the flocked surface structure having appropriate properties can prevent the attachment of marine organisms, and the flocked shape can maintain the effect for a long period of time. It has been found that the present invention has been achieved by the heading.

That is, the gist of the present invention is a surface structure for preventing attachment of marine organisms, which is characterized in that a ribbon made of a thin film of a polymer material is implanted.

In the present invention, the ribbon refers to a long flexible body having a sufficient thinness such that it can be swung in seawater and having a width approximately 100 times or more and 1000 times or less of the thickness. Such a ribbon oscillates in seawater to prevent biological attachment, and the oscillating property is maintained for a long time.

The material of the ribbon used in the present invention is required to have such a thickness that it can be easily rocked in seawater, and it is not damaged or deteriorated in seawater for a long period of time.
Polymer materials are used. Specifically, polyolefin,
Examples thereof include vinyl chloride and fluororesin.

The thickness, width, length, etc. of the ribbon are determined in consideration of the swingability of the ribbon in seawater, the entanglement with other ribbons, the manufacturing cost, etc. Width 1-10
mm, and a length of 10 to 100 mm are preferable. If the thickness is less than 5μ, it is difficult to manufacture the ribbon, and if it is more than 25μ, it is difficult to shake in seawater, and the effect of preventing biofouling is reduced. If the ribbon width is less than 1 mm, it behaves like a fiber, making it easier to get tangled with the surrounding ribbon, while if it is greater than 10 mm, the movement becomes poor due to the surroundings. When the length is shorter than 10 mm, the rocking property is reduced and the biofouling effect is reduced, while when the length is larger than 100 mm, the ribbon is easily entangled with the surrounding ribbon,
And the cost is high. For this reason, ribbons in the size range given above are preferred.

If the total density of the ribbons is set to be 3 to 30 times the area of the object, a preferable rocking surface can be obtained. The flocking may be performed directly on the surface of the target object, but the sheet-like object in which the ribbon is pre-flocked by a means such as adhesion, sewing, and weaving to a fabric or a sheet material of a polymer material is used as a marine structure. It is also possible to obtain the desired surface structure by sticking, winding, or fusing on.

A woven fabric or the like on which a ribbon is flocked is also useful as an anticorrosion coating if it is adhered to a steel pipe pile or the like with an adhesive such as epoxy. By using an underwater curing type adhesive, it is possible to adhere to an existing structure in water.
Further, even if the underwater structure is covered without the above-mentioned adhesion, the corrosion is considerably reduced. For such an orientation, it is advantageous to use an environment-blocking material such as resin or rubber as the covering body, that is, the flocked base material sheet.

The surface to which the present invention can be applied is the surface of any marine structure that operates in contact with seawater, such as the outer surface of a steel pipe used in an oil drilling rig, the inner surface of a seawater pipe, or the bottom of a ship.

Hereinafter, the present invention will be described more specifically with reference to Examples.

〔Example〕

A hard PVC pipe with a nominal diameter of 300 m and a length of 600 mm was subjected to the following treatment to produce a test piece.

A (invention): A high-density polyethylene ribbon with a thickness of 10 μm and a width of 3 mm of 30 mm, and a flocked sheet sewn with a density of ribbon area of about 10 cm ² / fabric cm ^{2 on} the entire outer surface Wrap B (comparative example): Wrap a sheet in which polyethylene fibers having a diameter of 10 μm were planted in the same manner as A in place of polyethylene ribbon C (comparative example): untreated (bare PVC pipe) These test pieces were used in Shirahama, Wakayama Prefecture. It was set up in January near the shore of the bay and observed 12 months later.
Barnacles, squirts, etc. adhered to a thickness of 20 mm or more. On B, the adhesion was a little small, but under the condition, the flocked fibers buckled and deformed and could no longer swing. On the other hand, in A according to the present invention, the attachment of the above-mentioned organisms was scarcely observed, and the swaying property of the hair transplant was sufficiently maintained.

It should be noted that the diameter of 10
The fiber of μ exhibits the same oscillating property to seawater as the ribbon of 10 μ in thickness according to the embodiment of the present invention at the initial stage of installation in seawater. The reason will be briefly described below.

The geometrical moment of inertia I of a ribbon with width b and thickness t is I = bt
It is a ^3/12. Since the force of seawater acting on this is a value proportional to the width b, the resistance coefficient of the ribbon is taken as 2 and this is 2b.
Assuming that f is a constant including the flow velocity and the rocker length, the amount of deflection is proportional to 2bf ÷ I = 24f / t ³ (1).

On the other hand, the geometrical moment of inertia I of the fiber of diameter d is I = π
d is a ^4/64. The force of seawater acting on this is df when the resistance coefficient is 1. Therefore, the amount of deflection is a value proportional to df ÷ I = 20f / d ³ (2). From (1) and (2), a fiber having a diameter equal to the thickness of the ribbon oscillates in the same manner as the ribbon in seawater.

Thus, as a result of the use of a ribbon and a fiber having the same rocking property in seawater in seawater in the initial stage, the fiber loses its rocking property in a relatively short period of time, but the ribbon loses its rocking property. It was confirmed that they could rock for a long period of time without any effect, and exhibited the effect of preventing biological attachment.

〔The invention's effect〕

As described above, the present invention enables the prevention of adhesion of marine organisms for a long period of time by virtue of the surface structure in which the thin polymer film is flocked in the form of a ribbon. As a result, there is no problem of marine environmental pollution, and the effect will continue for a long time, making a great contribution to the normal operation of a new or existing sea contact structure.

Claims (1)

[Claims] 1. A surface structure for preventing attachment of marine organisms, characterized in that ribbons made of a thin film of a polymer material are flocked.