JP2006193672A - Paint for preventing adhesion of aquatic life - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paint for preventing adhesion of aquatic life, effective for steadily preventing the adhesion of aquatic life such as alga, shellfish and crustaceans adhering to the bottom of ships, water supplying facilities of power plants and factories and fishing gears contacting with water of rivers, lakes and ocean to cause the increase of water flow resistance and the staining of the surface and releasing little chemical substances supposed to give adverse effect on nature such as environmental pollution. <P>SOLUTION: The paint for preventing the adhesion of aquatic life is composed mainly of a gelatinous polymer of a polyacrylic acid derivative obtained by the copolymerization of a monomer containing a reactive functional group. The paint chemically inhibits the adhesion of proteins derived from organisms, and changes the surface structure of the polymer at the micro level within the variation range of outdoor water temperature (about -5°C to +40°C) to physically prevent the adhesion and solidification of alga, shellfish and crustacean by so-called shake-off effect. Furthermore, the paint exhibits high peeling resistance by reacting with a reactive functional group on the surface to be coated with the paint. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a coating material that prevents aquatic organisms such as algae, shellfish, and crustaceans from adhering to and fixing on surfaces in contact with water such as rivers, lakes, and the ocean.

In contact with rivers, lakes, and marine water of ship bottoms, water supply facilities that take in cooling water such as nuclear and thermal power plants and seaside complexes, aquaculture nets, fishing gear, piers, docks, etc. (hereinafter referred to as underwater structures) On the surface, algae, shellfish, crustaceans, etc. adhere, gradually grow and stick with the passage of time, and as they increase, they cause increased water resistance and fouling. In the case of ships, the frictional resistance against water during navigation leads to a decrease in navigation speed and an increase in fuel costs. In the case of water transmission equipment at power plants, the power generation efficiency is reduced due to a malfunction of the cooling water flow. In the worst case, it can cause a serious accident. However, it is generally not easy to periodically physically remove the aquatic organisms that have once adhered to the surface of the underwater structure that contacts the water.

Therefore, in order to reduce this cleaning work, paints that prevent adhesion of these underwater organisms have been developed and provided to the market by elution of repellent chemical substances and partial water-solubilization of paint components.

In order to prevent the adhesion of aquatic organisms, conventionally used paints are those to which physiologically active components such as mercury compounds, copper compounds, arsenic compounds and organotin compounds are added. However, these compounds are inherently toxic to ecosystems, and some of them are suspected of acting as environmental hormones. There are some concerns. In addition, the effect of preventing the adhesion of underwater organisms cannot be said to have sufficient long-term durability, and it has been desired to provide an underwater organism adhesion prevention coating that is safer and has a long-lasting effect.

In recent scientific and technical literature, as a new method for preventing underwater biological adhesion, a technique for preventing the formation of a biofilm (biofilm) by radical polymerization of N-isopropylacrylamide (NIPAAm) on the substrate surface is announced. Has been. The following documents (Non-Patent Document 1 and Non-Patent Document 2) are those, and there is a description about the applicability to various indwelling base materials, underwater structures, ship bottoms, and the like.

However, in the methods described in these scientific and technical literatures, a substrate is created in a special reaction environment such as a plasma polymerization method, and data is only observed for an ideal simulated ecosystem environment. Although such a method can be realized in a laboratory environment with a small reaction scale, it cannot be used in industrial practice on an industrial scale.

In addition, it has been shown in other literature that a polymer containing N-isopropylacrylamide as a main component has a property of chemically repelling the adhesion of proteins (Non-Patent Document 3). Samples prepared under special reaction conditions such as the plasma polymerization method have only been examined, and are not provided as techniques that can be applied to industrial applications such as paint applications.

In addition, as seen in Japanese Patent Application Laid-Open No. 11-293183 (Patent Document 1), an underwater organism adhesion preventing paint using a low surface energy compound such as a silicone graft acrylic resin has also been proposed. There was a problem that a peeling phenomenon easily occurred between the film and the top coat film.

Japanese Patent Laid-Open No. 11-293183 Lower critical solubility temperature materials as biofouling release agents.Ista, LK; Lopez, GP Departments of Chemical and Nuclear Engineering, University of New Mexico, Albuquerque, NM, USA.Journal of Industrial Microbiology & Biotechnology (1998), 20 (2), 121-125. Surface-grafted, environmentally sensitive polymers for biofilm release.Ista, Linnea K .; Perez-Luna, Victor H .; Lopez, Gabriel P..Department of Chemical and Nuclear Engineering, The University of New Mexico, Albuquerque, NM, USA. Applied and Environmental Microbiology (1999), 65 (4), 1603-1609. Hirata, Isao; Okazaki, Masayuki; Iwata, Hiroo.Department of Biomaterial Science, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan. Polymer (2004), 45 (16), 5569-5578.

The technical problem of the present invention pays attention to such a problem, and it is possible to prevent algae, shellfish, crustaceans, etc. from adhering to the surface of the underwater structure in contact with water over a long period of time, and to prevent environmental pollution. It is to realize an underwater organism adhesion prevention coating that has almost no release of chemical substances that may adversely affect nature, such as excellent release resistance, and high industrial practicality.

The present inventors have found that the above problems can be solved by using a polyacrylic acid derivative gel polymer obtained by copolymerizing a reactive functional group-containing monomer, and have reached the present invention. That is, the present invention provides an underwater organism adhesion preventing coating characterized by containing a polyacrylic acid derivative gel polymer obtained by copolymerizing a reactive functional group-containing monomer as a main component.

The initial stage of the mechanism for algae, shellfish, and crustaceans to adhere to underwater structures is first adsorbed with organic substances such as proteins in the water on the surface, and bacteria attach to them to grow, called slime together with solids in water It is said that it starts from the formation of a biofilm layer (biofilm). It is considered that plankton-sized aquatic organism larvae adhere to these biofilm layers on the surface of the underwater structure material and grow with time, resulting in increased water resistance and fouling. Since the polyacrylic acid derivative gel polymer in the present invention has the property that proteins are inherently difficult to adhere, the initial stage can be chemically prevented.

In addition, the gel-like polymer has a mechanical strength that is practically necessary and sufficient because the reactive functional group introduced by copolymerization of the reactive functional group-containing monomer is three-dimensionally crosslinked between the polymers. It possesses flexible and variable physical properties derived from the hydrogel structure, and therefore it is also possible to suppress physical phenomena such as adhesion of protein components and larvae of aquatic organisms. Furthermore, the gel-like polymer reacts with the functional group present on the coated surface by the reactive functional group introduced by the copolymerization of the reactive functional group-containing monomer, and binds firmly to the coated surface, resulting in excellent peeling resistance. Can show gender.

As a polyacrylic acid derivative gel polymer obtained by copolymerizing a reactive functional group-containing monomer for use in the paint of the present invention, a polyacrylic acid derivative gel containing N-isopropylacrylamide as a main component (50 mol% or more) is used. Polymers are particularly effective. This gel-like polymer has an excellent property of chemically repelling the adhesion of biological proteins (Non-Patent Document 3), and when used as a main component of an underwater biological adhesion-preventing paint, it has an adverse effect on the natural environment. It also has excellent characteristics from the point that it is not necessary to contain the sustained-release biological repellent chemical substance concerned.

Further, this polymer containing N-isopropylacrylamide as a main component has a gel structure transition point in the vicinity of 30 ° C., and changes its microstructure greatly according to the change in water temperature. As a result, the change in water temperature within the ship navigation time, that is, on the earth, within the fluctuation range of the outdoor water temperature from the cold zone to the tropics or within the fluctuation range of the outdoor water temperature during the day and night (approximately -5 ° C to 40 ° C). It has been found that the surface structure of the molecules changes greatly at the micro level and has a so-called “shaking off” effect that prevents physical adhesion solidification. It was done.

The polyacrylic acid derivative gel polymer used in the present invention is obtained by copolymerizing at least one type of reactive functional group-containing monomer, and the reactive functional group has a reactive functional group having a surface chemical composition such as an undercoat surface. Excellent peeling resistance can be exhibited by forming a chemical covalent bond with the group.

As the reactive functional group-containing monomer in the polyacrylic acid derivative gel polymer used in the coating material of the present invention, an acrylic monomer having a reactive functional group such as an isocyanate group (or a chemical equivalent thereof) or a glycidyl group is used. Although effective, among them, 2-methacryloyloxyethyl isocyanate (also known as 2-isocyanatoethyl methacrylate), 2- (0-['-methylpropylideneamino] carboxyamino) ethyl methacrylate, glycidyl acrylate (also known as 2, 3-epoxy-1-propyl acrylate) and glycidyl methacrylate (also known as 2,3-epoxy-1-propyl methacrylate) have been found to have particularly good effects. The copolymerization amount of these reactive functional group-containing monomers is between 0.1 mol% and 50 mol%, more preferably 1 mol% to 10 mol, in the monomer composition constituting the polyacrylic acid derivative gel polymer. %.

In the present invention, a polyacrylic acid derivative gel polymer obtained by copolymerizing a reactive functional group-containing monomer is used as a component of a paint applied to a portion in contact with water, particularly a paint used as an underwater biological adhesion preventing paint. By using the underwater organism adhesion preventing paint of the present invention, it is possible to effectively and continuously prevent the adhesion of underwater organisms, and it is possible to effectively prevent both water resistance increase and fouling.

In the polyacrylic acid derivative gel polymer obtained by copolymerizing the reactive functional group-containing monomer, which is the main component of the paint of the present invention, the composition ratio of the acrylic acid derivative monomer and the reactive functional group-containing monomer is in molar ratio. Acrylic acid derivative monomer: Reactive functional group-containing monomer = 50: 50 to 99.9: 0.1, more preferably 90:10 to 99: 1.

Furthermore, in order to improve the gel transition temperature and / or physical properties of the polyacrylic acid derivative gel polymer of the present invention, in addition to the main acrylic acid derivative monomer capable of developing a gel-like structure, the acrylic resin as a subordinate component is added. It may be effective to copolymerize the acid derivative monomer and to change the copolymerization ratio as appropriate. Monomers that can be used for this purpose include, but are not limited to, acrylic acid, methyl acrylate, butyl acrylate, methacrylic acid, methyl methacrylate, 2-hydroxyethyl methacrylate, and the like. . In addition, by appropriately using a polyfunctional acrylic monomer, it is possible to further increase the cross-linked structure and reinforce the gel structure of the coating component.

By applying these monomer copolymerization techniques to underwater organism adhesion prevention paints, it becomes possible to design paints with optimum physical properties according to the water temperature of the application environment. That is, for tropical and subtropical areas where the average water temperature is high, a high temperature type with a gel transition temperature of 25-30 ° C., and in a cold zone with a low average water temperature, a low temperature type with a gel transition temperature of 5-10 ° C. Furthermore, in the temperate zone, it is possible to provide optimum desired physical properties according to the environment and application site, such as the intermediate temperature type, and to realize a superior effect of preventing underwater organism adhesion.

The coating material of the present invention has a polyacrylic acid derivative gel polymer obtained by copolymerization of a reactive functional group-containing monomer as its main component (main component for forming a coating film), and if necessary, a solvent or dilution Various additional or auxiliary components such as an agent, a pigment, and a filler can be contained. Usually, a good solvent for polyacrylic acid derivative gel polymer such as acetone, methyl ethyl ketone, tetrahydrofuran, 1,4-dioxane, ethyl acetate, etc. (however, it is aprotic and sufficiently dehydrated. The solution is applied to the surface to be treated (that is, the surface to be painted, such as an underwater structure). As for the coating method, since it has a reactive functional group introduced by copolymerization inside the polymer, certain precautions such as storage and operation under dry conditions are required in the stage before coating, but otherwise it is normal. There is no difference from the coating method.

The polyacrylic acid derivative gel polymer in the present invention is obtained by reacting a reactive functional group introduced into the polymer by copolymerization with a reactive functional group such as a hydroxyl group or an amino group present on the surface to be coated. It is designed to be a strong coating layer with excellent peel resistance. Therefore, when the underwater structure material is an inorganic material such as a metal, the primer treatment and / or undercoat coating containing a reactive functional group such as a hydroxyl group or an amino group corresponding to them is applied in advance. When is an organic polymer material, it is necessary to confirm that it is a surface material having those reactive functional groups. In some cases, the surface is roughened by sandblasting, etc., and the surface area is increased as much as possible to improve the physical adhesion, or the reaction site is chemically treated with alkali or acid treatment. May produce good paint results.

The film thickness of the painted surface is not particularly limited, but it is desired to be 1 micron or more, preferably 10 microns or more in order to better exhibit the effect of preventing the adhesion of aquatic organisms. However, this is a thickness (usually on the high temperature side) where the thickness is thinner in the transition phenomenon due to the micro-level temperature of the gel structure. Moreover, not only is it too thick, it is not economical, but a macro-level (large) rough surface is formed by mechanical friction or the like, and the chemical and physical underwater biological adhesion prevention characteristic of the present invention is characteristic. Should be avoided because it is expected that it will not work properly. Therefore, it is recommended that the thickness be 1 mm or less on the high temperature side (the smaller thickness side) of the gel transition temperature.

In order to make the coating effect of the polyacrylic acid derivative gel polymer in the present invention more reliable, a dry gas of 50 ° C. or higher and 200 ° C. or lower is blown also as a drying treatment of the coated surface. Alternatively, it is also recommended that heat treatment such as far-infrared irradiation having a similar heating effect is performed to promote the bonding by the reaction between the reactive functional group and the functional group on the surface of the undercoat, thereby enhancing the adhesion effect.

Specific embodiments of the present invention are described below, but the contents of the present invention are not limited thereto.

Radical polymerization of 98.1: 1.9 copolymer poly (NIPAAm-co-MOI) of N-isopropylacrylamide (NIPAAm) and 2-methacryloylethyl isocyanate (trade name: KarenzMOI [Showa Denko]) (MOI) It was produced in. At this time, in order to prevent hydrolysis of isocyanate in KarenzMOI, the solvent (1,4-dioxane) used in the polymerization is sufficiently dehydrated and a redox polymerization initiator (benzoyl peroxide-dimethylaniline) that does not require heating. ) Was used.

A 3 × 3 cm 300 μm thick nylon film was immersed in a 2N aqueous sodium hydroxide solution at room temperature for 3 hours to hydrolyze the film surface. On this surface, 300 μl of a 10-w / v% poly (NIPAAm-co-MOI) 1,4-dioxane solution was dropped and air-dried. After repeating this three times, a crosslinked thin film of poly (NIPAAm-co-MOI) was formed by heating at 50 ° C. for 2 hours. The thickness of the crosslinked thin film in a dry state was 25 μm.

98.4: 1. Of N-isopropylacrylamide (NIPAAm) and 2- (0-['-methylpropylideneamino] carboxyamino) ethyl methacrylate (trade name: KarenzMOI-BM [Showa Denko]) (MOIBM). 6 copolymer poly (NIPAAm-co-MOIBM) was prepared by radical polymerization. A self-assembled film of 11-mercapto-1-undecanol was formed on a gold thin film on a 2.5 × 2.5 cm glass substrate, and 2.0 w / v% poly (NIPAAm-co-MOIBM) was formed on this surface. 300 μl of an acetone solution was added dropwise and heated at 150 ° C. for 90 minutes to form a crosslinked thin film of poly (NIPAAm-co-MOIBM). The thickness of this crosslinked thin film in a dry state was 2 μm.

A 99: 1 copolymer poly (NIPAAm-co-GMA) of N-isopropylacrylamide (NIPAAm) and glycidyl methacrylate (2,3-epoxy-1-propyl methacrylate) (GMA) was prepared by radical polymerization. . The solvent was 1,4-dioxane, the polymerization catalyst was benzoyl peroxide, and the reaction conditions were 80 ° C. and 2 hours.

A 3 × 3 cm 300 μm thick nylon film was immersed in a 2N aqueous sodium hydroxide solution at room temperature for 3 hours to hydrolyze the film surface. On this surface, 300 μl of a 10-w / v% poly (NIPAAm-co-GMA) 1,4-dioxane solution was dropped and air-dried. After repeating this three times, a crosslinked thin film of poly (NIPAAm-co-GMA) was formed by heating at 120 ° C. for 3 hours. The thickness of this crosslinked polyNIPAAm thin film in a dry state was 20 μm.

The coated film or glass substrate of Example 1, Example 2, and Example 3 and an unpainted nylon film are immersed in seawater (collected in the vicinity of Tamano City, Okayama Prefecture), and the container has an environment with temperature fluctuations. It was allowed to stand (in a simple outdoor greenhouse, 30-35 degrees during the day, 20-25 degrees at night), and the progress was observed. At the time when one month passed from the start of immersion, green algae were already attached to the uncoated nylon film so that the green algae were sufficiently visible, but hardly any attached organisms were observed on the poly-NIPAAm coated film surface. Thereafter, even when 6 months passed, formation of attached organisms was not observed on the films and substrates of Example 1, Example 2, and Example 3.

Claims (5)

An underwater bioadhesion-preventing paint comprising, as a main component, a polyacrylic acid derivative gel polymer obtained by copolymerizing a reactive functional group-containing monomer. 2. The underwater organism adhesion preventing paint according to claim 1, wherein the polyacrylic acid derivative gel polymer is a polymer containing 50 mol% or more of N-isopropylacrylamide as a constituent monomer unit. The underwater organism adhesion preventing paint according to claim 1 or 2, wherein one of the reactive functional group-containing monomers is 2-methacryloyloxyethyl isocyanate. One of the reactive functional group-containing monomers is 2- (0-['-methylpropylideneamino] carboxyamino) ethyl methacrylate, and prevents the adhesion of underwater organisms according to claim 1 or 2. paint. The underwater organism adhesion preventing paint according to claim 1 or 2, wherein one of the reactive functional group-containing monomers is glycidyl acrylate or glycidyl methacrylate.