JPH04277571A - Antifouling coating material - Google Patents

Abstract

PURPOSE:To produce the title material which is easily produced, has excellent antifouling properties and a low coefficient of friction in water, and does not pollute the marine environment by compounding a fluorinated pitch as the effective antifouling component into the material. CONSTITUTION:The title material contains a fluorinated pitch. The pitch is white to light yellow to brown powder, represented by the compsn. formula: CFx (wherein 0.5<=x<1.8), excellent in resistance to water and sea water as well as to chemicals such as an alcohol, an acid, or a nonfluorinated org. solvent, very excellent in the stability in air, and obtd. by fluorinating a coal- or petroleum-derived pitch. The title material is superior in antifouling properties to a formerly known antifouling coating material, has a low coefficient of friction in water when used for shipbottom coating, and does not pollute the marine environment since it contains no hazardous substance such as an organotin compd. In addition, the pitch is very soluble in a solvent, facilitating the production of the material.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a paint (hereinafter referred to as "coating material") that is applied to areas that come into contact with seawater in order to prevent damage (generally referred to as fouling) due to adhesion of marine organisms to areas that come into contact with seawater. (simply referred to as antifouling paint). In addition,
In this specification, "%" and "parts" mean "% by weight" and "parts by weight", respectively.

0002

[Prior art and its problems] Undersea installation parts of marine structures such as ship bottoms, offshore bridges, submarine aquariums, buoys, and dams;
Places that constantly come into contact with seawater, such as cooling seawater intake channels and water guide tubes or pipes of thermal power plants and various plants, fishing nets, etc., are exposed to barnacles, oysters, mussels, hydrobugs, cellulla, bryozoans, sea squirts, sea lettuce, green laver, etc. Shellfish and algae attach and multiply. For example, in the case of a ship, this can be caused by a decrease in speed due to increased frictional resistance during navigation, an increase in fuel consumption, an increase in the cost of cleaning the bottom of the ship, and a loss of costs due to the suspension of operations for cleaning. This will result in an increase in overhead costs. Furthermore, in the case of cooling seawater intake channels or water guide tubes, problems such as a decrease in the capacity of various devices occur due to a decrease in the amount of water intake due to blockage of these channels.

[0003] As antifouling measures to deal with the above-mentioned biofouling, methods such as chlorine injection, seawater electrolysis, and application of antifouling paint have been proposed, and in particular, the method of applying antifouling paint is the most effective. Since it is also economical, it is widely put into practical use. Antifouling paints that have been most widely used over the past 20 to 30 years contain organic tin compounds such as tributyltin (TBT) compounds and triphenyltin (TPT) compounds as antifouling active ingredients. In the antifouling method using these paints, the tin compound, which is an active antifouling ingredient, is continuously eluted little by little from the surface of the paint film in the sea, thereby killing or repelling marine organisms and preventing their adhesion. It uses the principle of preventing reproduction. In addition, when applying this type of paint containing specific resin components to the hull, the pH level must be 8.
．． 3. The paint is gradually hydrolyzed in the seawater around the ship, and a smooth coating surface is always formed, which reduces frictional resistance on the hull, lowers fuel consumption, and enables economical navigation. will also be achieved. This kind of self-polishing type (se
(lf polishing) ship bottom paint became widely used from the 1960s to the 1970s due to its outstanding effectiveness.

0004

However, since around 1980, it has been discovered that organic tin compounds derived from antifouling paints are accumulated in seafood, and pollution of the marine environment by antifouling paints has become a worldwide problem. As organic tin-based antifouling paints begin to attract attention, regulations on organic tin-based antifouling paints are gradually being tightened in various countries. In particular, TBT-based compounds and TPT-based compounds are subject to strict legal regulations.

On the other hand, as non-leaching type antifouling paints that utilize the physical property of low surface energy, paints containing graphite fluoride (see Japanese Patent Application Laid-open No. 44568/1983) and silicone-based synthetic resins are used. Paints and the like have been proposed, but they all use expensive materials and are therefore impractical from an economic standpoint.

[0006]

[Means for Solving the Problems] As a result of extensive research in view of the problems of the prior art as described above, the present inventors have discovered that the fluorinated pitch developed by the present inventors has excellent properties against marine organisms. It has been discovered that not only does it have antifouling properties, but when used as a ship bottom paint, it also has the effect of lowering the frictional resistance against seawater.

That is, the present invention provides an antifouling paint characterized by containing fluorinated pitch.

The fluorinated pitch used as the antifouling active ingredient in the present invention is a powder produced by fluorinating coal-based or petroleum-based pitch. The method for producing fluorinated pitch is not particularly limited, but for example, pitch may be directly fluorinated with fluorine gas at 0 to 350°C according to the method described in JP-A No. 62-275190. It can be manufactured by

This fluorinated pitch has the composition formula CFx (0.
5≦x<1.8), its color is white to pale yellow to brown, and it has excellent water resistance, seawater resistance, and chemical resistance to alcohol, acids, non-fluorinated organic solvents, etc. It also has excellent stability in air. Furthermore, in the present invention, when such fluorinated pitch is further heat-treated in a fluorine atmosphere at a temperature of about 150 to 310°C for about 5 minutes to about 10 hours, the above characteristics are further improved. At the same time, it is possible to further improve the solubility in fluorine-based solvents used during paint preparation.

In particular, when viewed as an active ingredient in antifouling paints, fluorinated pitch has a surface energy as represented by a contact angle with water (approximately 145°) that is higher than that of polytetrafluoroethylene (approximately 109°). It is extremely low compared to
The frictional resistance of paint in water can be significantly reduced.

Furthermore, fluorinated pitch is soluble in fluorinated aromatic solvents such as perfluorobenzene, unlike fluorinated resins such as polytetrafluoroethylene and fluorinated carbon materials such as fluorinated graphite. Therefore,
It is easy to prepare a paint containing fluorinated pitch, and the resulting paint has excellent performance in which the fluorinated pitch is uniformly dissolved or dispersed. Furthermore, even when manufacturing paints using solvents other than those mentioned above, powdered fluorinated pitch has very good dispersibility compared to fluororesins, fluorinated carbon, etc. , the amount of dispersant used is significantly reduced, and the time required for dispersion treatment is also significantly shortened.

[0012] In the air, substances are less likely to adhere or adhere to surfaces with lower surface energy, but the behavior of living organisms in water is different. That is, in water, 26 to 28
There is little adhesion of living things to surfaces with a surface energy on the order of dynes/cm, and fluorine-containing polymers with a lower surface energy are conversely more likely to be contaminated by living things. In the antifouling paint according to the present invention, fluorinated pitch with low surface energy can be easily dispersed in the paint, and the surface energy of the paint film can be freely adjusted by adjusting the amount, so that it is difficult for organisms to adhere to it. It is possible to form a surface.

The antifouling paint according to the present invention contains, in addition to fluorinated pitch, paint constituents such as known resins and organic solvents, and if necessary, plasticizers, solubilizers, coloring pigments, and extender pigments. , a leveling agent, an antifoaming agent, an antisettling agent, and other additives. As components other than fluorinated pitch, known components can be used as they are, as long as they do not react with fluorinated pitch.

As the resin component, those used in ordinary antifouling paints can be used, and specifically, synthetic resins such as vinyl chloride resin, vinyl acetate resin, alkyd resin, and acrylic resin; rosin Natural resins such as; synthetic rubbers such as chlorinated rubber; and the like.

The organic solvent is not particularly limited as long as it can dissolve or disperse the fluorinated pitch. Specifically, aromatic hydrocarbon solvents such as benzene, toluene, and xylene; hexafluorobenzene, perfluoromethylcyclohexane, perfluorodimethylcyclohexane, perfluorodecalin, perfluorophenanthrene, chloropentafluorobenzene, perfluoro Examples include halogen-containing solvents such as tributylamine. In addition, when using the heat-treated fluorinated pitch described above, fluorocarbons such as 1,1,2-trichloro-1,1,2-trifluoroethane, dibromotetrafluoroethane, dichlorodifluoromethane, and dichloropentafluoropropane are used. can also be used as a solvent.

[0016] The proportions of each component in the antifouling paint of the present invention are as follows:
Although not particularly limited, about 1 to 30 parts of fluorinated pitch is usually blended with 100 parts of the vehicle component consisting of an organic solvent and a resin component. In such a basic composition, the above-mentioned known additives can be further blended as necessary. The antifouling paint according to the present invention can be easily produced by mixing the above-mentioned components in a conventional manner, for example, using a dispersing device such as a ball mill, and uniformly dissolving or dispersing each component.

The antifouling paint of the present invention is applied to areas requiring antifouling treatment using a spray, brush, etc. in the same manner as known antifouling paints.

[0018]

[Effects of the Invention] The antifouling paint of the present invention exhibits the following remarkable effects compared to known antifouling paints. (1) Excellent antifouling performance. (2) When used as a ship bottom paint, the frictional resistance in water is low. (3) Does not contain harmful substances such as organic tin compounds,
There is no risk of contaminating the marine environment. (4) Fluorinated pitch, which is an active ingredient in antifouling paints, has excellent solubility and dispersibility in solvents, making it easy to manufacture paints.

[0019]

EXAMPLES Examples are shown below to further clarify the features of the present invention.

Example 1 and Comparative Example 1 Each material was dispersed and mixed in a ball mill in the proportions (parts by weight) shown in Table 1 to prepare an antifouling paint according to the present invention and an antifouling paint according to a comparative example.

[0021]

[Table 1]

Next, the following tests were conducted using the obtained antifouling paint. I. Underwater Frictional Resistance Test Rotating Disk Method The frictional resistance of the coating film was measured using an underwater frictional resistance testing device. i.e. diameter 20cm, thickness 2m
Apply antifouling paint to a steel disc of 1.5 m using a spin coater,
This disk was attached to a rotating shaft and immersed in water for 200 r.
．． p. m. The torque value of the coating film was recorded with a recorder via a torque transducer and an amplifier.

The torque value of a disk rotating in seawater can be calculated theoretically by the following formula (1) (University course Mechanical Engineering,
Flow Studies, written by Koji Hirose, Kyoritsu Publishing Co., Ltd.). Mt=4ρπ2n2γδ5Cf/g
(1) However, in equation (1), Mt: Torque value (Kg・m) ρ: Density of seawater (Kg/m3) n: Number of rotations of the disc
(1/sec) γδ: radius of disk (m) Cf: coefficient of frictional resistance g: gravitational acceleration (9.8 m/sec2).

After determining the torque value of the coating film formed from each paint using the above equation (1), using the value of the coating film of Comparative Example 1 as a standard (1.000), calculate the torque value of the coating film of Example 1. The ratio of torque values was determined, and this was taken as the ratio of frictional resistance coefficients. The results are shown in Table 2.

II. Antifouling performance test Steel plate test pieces (300 mm x 300 mm x 2 mm) were brush-coated with the paints obtained in Example 1, Comparative Examples 1 and 2, and mounted on a raft in the Sea of Japan in Toyoura District, Yamaguchi Prefecture for 2 m.
The specimens were hung at a depth of 1, and the biofouling status (antifouling performance) was evaluated after 3 months, 6 months, and 9 months. The antifouling performance was evaluated based on the biological adhesion area (%) observed with the naked eye. The results are also shown in Table 2.

[0026]

[Table 2]

As is clear from the results shown in Table 2, the antifouling paint according to the present invention has less underwater frictional resistance and superior antifouling performance than the antifouling paint according to Comparative Example 1.

Claims (1)

[Claims] 1. An antifouling paint characterized by containing fluorinated pitch.