JPS63194012A - Surface structure for oceanic-lie-attachment-proofness - Google Patents

Abstract

PURPOSE:To prevent oceanic life from being attached to for a long time, by implanting ribbons consisting of the macromolecular material of polyethylene and the like and having dimensions for oscillation in the seawater, on the surface of a marine structure working in contact with the seawater. CONSTITUTION:A flocked sheet wit the ribbons of the thickness of approx. 10mu and the width of approx. 3mm consisting of the macromolecular material of polyethylene or the like, seamed with the sheet length of approx. 30mm and the density of the ribbon area 10cm<2>/cloth cm<2>, on the cloth is manufactured. After that, the sheet is fitted, wound up, or fusion-welded on the whole external surface of a marine structure working in contact with the seawater. The ribbons fitted on the sheet are prevented from being damaged, deteriorated or tangled together for a long time, and are oscillated continuously in the seawater.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is directed to the prevention of marine life on structures that operate in contact with seawater, such as the outer surface of steel pipes used in oil drilling rigs, the inner surface of seawater pipes, and the bottom of ships. It relates to a surface structure that prevents adhesion.

[Conventional technology]

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

[Problem that the invention seeks to solve]

However, with this conventional method, not only is marine pollution caused by antifouling agents in the paint considered a problem (also, the effective period is only 2 to 3 years).
Limited to 2018.

As an alternative to such antifouling paints, coatings with copper-based metals or coatings with low surface energy paints such as silicone resins are beginning to be adopted. However, these also had limitations such as wear and tear or a short effective lifespan.

In addition, as another method, a large number of fine hair fibers are implanted on the surface located in the sea, and the rocking of these fine hair fibers in the sea is used to prevent biofouling.
No. 60-159044, etc.

However, in experiments conducted by the present inventors, thin fibers with sufficient swingability tend to be deformed, damaged, or become entangled with each other in a relatively short period of time, and as a result, the initial swingability is impaired. It was found that there was a problem in that the biofouling prevention effect was reduced.

The present invention was made in view of such problems.

The purpose of the present invention is to provide a surface structure that prevents the adhesion of marine organisms and 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 problems, the present inventors found that a flocked surface structure with appropriate properties can prevent marine organisms from adhering, and that the shape of the flocked hairs can maintain the effect over a long period of time. Heading 0 The present invention has been achieved.

That is, the gist of the present invention is a surface structure for preventing the adhesion of marine organisms, which is characterized by flocking ribbons made of a thin film of a polymeric material.

In the present invention, a ribbon refers to a long flexible body that is sufficiently thin to be able to swing in seawater and has a width that is approximately 100 times or more and 1000 times or less the thickness.

Such a ribbon oscillates in seawater, prevents biological attachment, and maintains its oscillation properties over a long period of time.

The material for the ribbon used in the present invention must be thick enough to swing easily in seawater, and must have properties that will not cause damage or deterioration over a long period of time in seawater. is used. Specifically, polyolefin, vinyl chloride, fluororesin, etc. can be exemplified.

Thickness 9 The width, length, etc. of the ribbon are determined based on the ribbon's swayability in seawater, interaction with other ribbons, manufacturing cost, etc., but in general, the thickness is 5 to 25 μm. .

It is preferable to have a banner of 1 to 10 m and a length of 10 to 100 n. If the thickness is thinner than 5 μm, ribbon production is difficult.

If it is thicker than 25μ, it will be susceptible to shaking in seawater and the effect of preventing biofouling will be reduced. If the ribbon width is smaller than 1fi, it behaves similarly to fibers and becomes easily entangled with surrounding ribbons.

On the other hand, if the crane is larger than 10 cranes, it will have difficulty moving due to its interaction with its surroundings. If the length is shorter than Iota, the oscillation will be reduced and the biofouling effect will be lowered, while if it is longer than 10 (1 m), it will be easy to get entangled with the surrounding ribbons and the cost will be high. For these reasons, Ribbons within the size ranges described above are preferred.

A preferable rocking surface can be obtained by setting the ribbon density so that the total area of the ribbons is 3 to 30 times the area of the object. Flocking can be performed directly on the surface of the object, such as cloth or polymer sheet material.

A sheet-like material with pre-flocked ribbons is attached to the three marine structures by means such as gluing, sewing, or weaving.

A desired surface structure can also be obtained by wrapping, fusing, etc.

Surfaces to which the present invention can be applied are any surface of any offshore structure that operates in contact with seawater, such as the outer surface of steel pipes used in oil drilling rigs, the inner surface of seawater pipes, and the bottom of ships.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

(Example) A test specimen was manufactured by applying the following treatment to a hard PVC pipe with a nominal diameter of 300fi and a length of 600fi.

A (present invention): A flocked sheet made of high-density polyethylene and sewn with a ribbon of thickness 1081 width 3fi at a density of 30 crane piles and ribbon area of approximately 10 -/fabric is wrapped around the entire outer surface B. (Comparative example): Instead of the polyethylene ribbon, a sheet of polyethylene fibers with a diameter of 10μ was wrapped in the same manner as in A. (Comparative example): Untreated (bare PVC pipe) These test specimens were placed on the shore of Shirahama Bay, Wakayama Prefecture. When it was installed nearby in January and observed 12 months later, it was found that in C, Kanzaki, fujibo, sea squirt, etc. were attached to a thickness of more than 20 m, while in B, there was a little less adhesion, but there were flocked fibers sitting under it. A situation was observed in which it was bent and deformed and could no longer swing.

On the other hand, in case A based on the present invention, almost no adhesion of the above-mentioned organisms was observed, and the swingability of the flocked hair was sufficiently maintained.

In addition, the diameter 10 used as a comparative example in the above test
At the initial stage of installation in seawater, the .mu. fibers exhibit the same swayability in seawater as the 10.mu. thick ribbon according to the embodiment of the present invention. The reason for this will be briefly explained below.

The moment of inertia I of a ribbon of width S and thickness t is.

t-bts712, and the force of seawater acting on it is proportional to the width of the ribbon, so the drag coefficient of the ribbon is set to 2.
If we take this as 2br (B is a constant including the flow velocity and the length of the rocking body), then the amount of deflection is.

It becomes a value proportional to 2bf+1=24f/13-.--(1).

On the other hand, the moment of inertia I of a fiber with diameter d is:

■=πd'/64. What is the force of seawater acting on this?

If the resistance coefficient is 1, it becomes df. Therefore, the amount of deflection is.

The value is proportional to df+1=2of/d' −·−(2). fl+, [21 From this, a fiber whose diameter is equal to the thickness of the ribbon oscillates in the same way as the ribbon in seawater.

In this way, as a result of using ribbons and fibers in seawater that initially exhibit the same swayability in seawater, the fibers lose their swayability in a relatively short period of time, but the ribbon loses its swayability. without any
It was confirmed that the rocker can be rocked for a long period of time and exhibits the effect of preventing biofouling.

〔Effect of the invention〕

As described above, the present invention makes it possible to prevent marine organisms from adhering to the surface for a long period of time due to the surface structure in which thin polymer films are flocked in the form of ribbons. As a result, there is no problem of marine environmental pollution, and the effect lasts for a long time, making a tremendous contribution to the normal operation of new or existing sea-facing structures.

Claims (1)

[Claims] A surface structure that prevents the adhesion of marine organisms, characterized by flocked ribbons made of thin polymer film.