JPH09118844A - Stainproof coating composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a stainproof coating composition capable of forming a film excellent in enzyme stability in the coating or film, stainproof ability and its durability. SOLUTION: This stainproof coating composition contains (A) a lipid modifying enzyme (e.g. a protease such as pepsin or trypsin, a polysaccharase such as α- and β-glucosidase or amyloglucosidase) which is solubilized in an organic solvent by modifying with a lipid [e.g. a compound of the formula (R is a 6-20C hydrocarbon)] having hydophilic groups selected from a group consisting of sugar, a phosphoric acid group, a sulfonic acid group and an ammonium salt and (B) a resin for coating.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an antifouling coating composition, and more particularly to an antifouling coating composition containing an enzyme solubilized in an organic solvent by modifying with a lipid.

[0002]

2. Description of the Related Art Antifouling paints have been conventionally used to prevent organisms from adhering to the surface of structures in the sea. However, the antifouling paint generally contains a toxic compound such as a tributyltin oxide-based heavy metal compound as an antifouling agent and has an adverse effect on the environment.

Recently, instead of such toxic compounds,
An antifouling paint using an enzyme with low toxicity as an antifouling agent is drawing attention.

For example, JP-A-2-227465 and 2-2274.
No. 71 and No. 4-252284 disclose antifouling coating compositions containing a protease such as a protease.

However, all of the coating compositions disclosed therein are inferior in the stability of the enzyme in the coating material and the coating film, and the enzyme is easily deactivated. Therefore, the formed coating film is inferior in antifouling property and lacks in its sustainability. There is also a problem that the preparation method is complicated.

[0006]

SUMMARY OF THE INVENTION The present invention is to solve the above-mentioned conventional problems.
It is an object of the present invention to provide an antifouling coating composition that forms a coating film having excellent stability of enzymes in the coating material and coating film and excellent antifouling property and its durability.

[0007]

The present invention has 6 to 30 carbon atoms.
The present invention provides an antifouling coating composition containing a lipid-modifying enzyme solubilized in an organic solvent by being modified with the above lipid, and a coating resin, thereby achieving the above object.

Enzymes that can be used in the present invention include hydrolases such as proteolytic enzymes and polysaccharide degrading enzymes. By using such an enzyme, proteins and polysaccharides relating to the attachment mechanism of marine periphyton can be decomposed and the attachment thereof can be prevented. In addition, the attachment can be prevented by degrading the cell wall of the attached organism.

Examples of proteolytic enzymes include proteases and peptidases that hydrolyze peptides. For example, pepsin from animal organs, trypsin, chymotrypsin, carboxypeptidase, thermolysin, casepsin and aminopeptidase, papain from plant tissue, chymopapain, promelin and aminopeptidase, microorganism-derived casepsin peptidase, proteinase and dipeptidase and the like. .

Examples of polysaccharide degrading enzymes include glucosidases that hydrolyze glucosidic bonds of sugars. Examples include α and β-glucosidase, amyloglucosidase, α and β-glucanase, α and β-galactosidase, α and β-amylase, glucoamylase, cellulase, chitinase, chitosanase, pectinase and lysozyme.

The term "lipid" as used herein means a compound having a long-chain alkyl group, a hydrophobic group and a hydrophilic group. The lipid used in the present invention may be either a natural lipid or a synthetic lipid, but preferably has 6 to 30 carbon atoms. If it is too short, it is difficult to modify the enzymatic properties even if it is modified, and if it is too long, the enzyme function is difficult to be expressed in the lipid modifying enzyme. Further, it is preferable that these have a hydrophilic portion selected from the group consisting of sugar, phosphoric acid group, sulfonic acid group and ammonium salt. This is because these groups easily bond with the hydrophilic groups on the enzyme surface, and the modifying enzyme has good stability.

The natural lipid may be either a neutral lipid or an ionic lipid. For example, neutral lipids include glyceroglycolipids such as monogalactosyl diglyceride and galactosyl glucosyl diglyceride, monoglucosylceramide, sphingoglycolipids such as ceramide hexoside and ganglioside, sterol glycosides, cardenolide glycosides and saponins. And steroidal glycosides and fatty acids such as diacyltrehalose and triacylglucose. Anionic lipids include phospholipids such as phosphatidylinositol, phosphatidylglycerol and phosphatidic acid. Examples of the amphoteric lipid include phospholipids such as phosphatidylcholine, phosphatidylethanolamine and phosphatidylserine.

As the synthetic lipid, a synthetic bilayer film forming compound can be used. For example, sorbitan monopalmitate, sorbitan monostearate, sorbitan dipalmitate, sorbitan distearate, ethylene glycol dipalmitate, ethylene glycol distearate, polyoxyethylene dipalmitate and polyoxyethylene distearate. Examples thereof include mono and dialkyl phosphates, mono and dialkyl polyethylene glycols, mono and dialkyl sulfosuccinic acids, mono and dialkyl glycolipids, and mono and dialkyl ammonium salts.

Expression

[0015]

Embedded image

[In the formula, each R is independently a C _{6 to} C ₂₀ hydrocarbon group. ] The lipid represented by the above is also preferable for use in the present invention. This is because the obtained enzyme has particularly excellent solubility in organic solvents.

The coating composition of the present invention can be obtained by incorporating an enzyme solubilized in an organic solvent by modifying with a lipid into the coating composition.

As a method for modifying the enzyme with a lipid, for example, the enzyme is dissolved in a buffer solution having a pH of 4.0 to 9.0, and the lipid is added dropwise to the solution with stirring at 0 to 30 ° C., preferably under cooling. . The lipid is generally dissolved in a small amount of methanol, ethanol, propanol, acetone, methyl ethyl ketone, other hydrophilic organic solvent, or dissolved in a buffer solution and added dropwise.

As the stirring method, a stirring device such as a stirring blade, a magnetic stirrer or a homomixer may be used. The mixture is stirred while being sufficiently cooled to precipitate and precipitate the lipid-modifying enzyme. The precipitate is separated by centrifugation or filtration, washed with a buffer solution and distilled water, and then freeze-dried or fluidized-bed dried to obtain a powdery lipid-modifying enzyme.

Mixing ratio of solid weight of lipid and enzyme
The (lipid / enzyme) is preferably in the range of 0.2 to 100, particularly 0.4 to 10. If it is less than 0.2, a complex cannot be formed, and 1
When it is 00 or more, the enzyme activity becomes too small. The buffer solution for dissolving the enzyme may be dissolved at a ratio of, for example, 0.02 to 20.0 ml per 1 mg of the enzyme, and when dissolving the lipid in a solvent, for example, 0.002 to 0.1 ml of hydrophilic organic solvent per 1 mg of the lipid. It can be dissolved and used.

The enzyme solubilized in the organic solvent as described above includes toluene, xylene, butyl acetate, MIBK and n-.
It can exist stably in an organic solvent such as butanol for a long period of time while maintaining its activity. Therefore, these can be contained in various organic solvent-based coating compositions and water-based coating compositions that have been conventionally used as antifouling coating compositions, by a method known in the field of coating production. Then, such an enzyme exerts an excellent antifouling effect even after the coating composition is formed as a coating film.

The lipid-modifying enzyme has a weight ratio of the lipid-modifying enzyme and the coating resin (lipid-modifying enzyme / coating resin) of 0.00001 to
1, and more preferably 0.001 to 0.01 is contained in the antifouling coating composition in an amount in the range of 0.001 to 0.01. If this weight ratio is 0.00001 or less, the enzyme activity in the resin is too low to expect the effect of the enzyme, and if it is 1 or more, the resin properties are lost.

The coating resin usable in the coating composition of the present invention is not particularly limited as long as it is known to those skilled in the art. Preferably, for example, vinyl chloride resin, chlorinated rubber resin, chlorinated polyethylene resin, chlorinated polypropylene resin, acrylic resin, styrene-butadiene resin,
Polyester resin, epoxy resin, polyamide resin,
Petroleum resin, silicone resin, silicone rubber resin,
Examples thereof include organic solvent-based coating resins such as wax, paraffin, rosin ester and rosin-based resin, and water-based coating resins such as acrylic emulsion resin, epoxy emulsion resin and vinyl acetate resin. These may be used alone or in combination of two or more.

Further, the coating composition of the present invention may contain additives such as a plasticizer, a coloring pigment, an extender pigment and a solvent, which are generally used in the coating composition, in a generally used amount.

[0025]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto.

Preparation Example 1 10 g of a protease derived from Butilis subtilis was dissolved in 5 liters of a phosphate buffer (0.1 M, pH 7.0) and centrifuged to remove insoluble matter to obtain a solution a. . Solution b was obtained by dissolving 10 g of the nonionic lipid didodecyl glutamate gluconamide in 100 ml of acetone. Solution b was added dropwise to solution a which was stirred at ice temperature, and stirring was continued for 4 hours at ice temperature, and then left overnight at 4 ° C. The solution in which the precipitate was formed was centrifuged (4 ° C., 4000 g, 10 min), the supernatant was removed, and the remaining precipitate was washed with phosphate buffer and distilled water. Then, this solid was freeze-dried to obtain 3.7 g of powdered lipid-modifying enzyme 1. The obtained lipid modifying enzyme 1 is
It was identified by UV spectrum.

Preparation Examples 2 to 8 Lipid modifying enzymes 2 to 8 were prepared in the same manner as in Preparation Example 1 except that the combination of the enzyme and the lipid in Preparation Example 1 was changed as shown in Table 1.

[0028]

Preparation Example 1 2 3 4 5 6 7 8 Enzyme content (g) Protease (B. Subtilis) 10--10 10 10 10 10 Chitinase (Bacillus sp.)-10------Lysozyme ( Chicken Egg White)--10----- Lipid content (g) Didodecyl glutamate 10 10 10 40 5 2--Gluconamide--------Sorbitan monopalmitate------10 -Phosphatidylcholine-------10

Example 1 5 g of the lipid-modifying enzyme 1 and a vinyl chloride-vinyl isopropyl ether copolymer "Laroflex MP-45" 30 manufactured by BASF
g, 25 g of natural rosin "WW rosin" manufactured by Arakawa Chemical Industry Co., Ltd., 25 g of xylol and 15 g of methyl isobutyl ketone were placed in a container and dispersed at 5,000 rpm for 15 minutes using a high speed disper to obtain an antifouling coating composition. 300 with anticorrosion coating
The obtained coating composition was applied to a test steel sheet having a size of × 100 mm so that the dry film thickness was 60 to 80 μm, and dried for 1 day to obtain an antifouling coated steel sheet.

Evaluation of Antifouling Property of Coating Film The antifouling coated steel sheet was immersed in a test raft off Tamano City, Okayama Prefecture at a depth of 1 m in the sea. The surface of the coating film was visually observed at predetermined intervals to examine the degree of contamination by attached organisms. Table 4 shows the results. The numerical values in Table 4 are the area ratios of fouling by attached organisms.
(Antifouling property (%)) In addition, an unpainted test steel plate that had been subjected to anticorrosion coating was also dipped at the same time as a control sample.

Evaluation of coating stability A part of the obtained coating composition was stored at 25 ° C. for 1 month, 2 months and 3 months, respectively. Then, the antifouling property of the paint after storage for each period was evaluated in the same manner. Table 6 shows the results.

Examples 2-11 and Comparative Examples 1-6 An antifouling coating composition was obtained in the same manner as in Example 1 except that the formulations shown in Tables 2 and 3 were used, and the antifouling property was evaluated. The results are shown in Tables 4 and 5. However, the evaluation of the antifouling property of the paint after storage for 1 month, 2 months and 3 months was carried out according to Example 3 and
12 and the coating compositions of Comparative Examples 4, 5 and 6. The results are shown in Tables 6 and 7.

[0033]

[Table 2] Example compounding amount (g) 1 2 3 4 5 6 7 8 9 10 11 12 Lipid modifying enzyme 1 5-------1 0.1 5 7 Lipid modifying enzyme 2-25----- -----Lipid modifying enzyme 3--5---------Lipid modifying enzyme 4---15--------Lipid modifying enzyme 5----5---- ---Lipid modifying enzyme 6-----10------Lipid modifying enzyme 7------5-----Lipid modifying enzyme 8-------5--- -Laroflex MP-45 ^a 30 30 30 30 30 30 30 30 30 30 30 55 30 WW Rosin ^b 25 10 25 25 25 25 25 25 25 25 15 Cuprous oxide------------10 Xylol 25 25 25 25 25 25 25 25 27 28 25 25 Methyl isobutyl ketone 15 15 15 15 15 15 15 15 15 17 17 15 15 ^a Vinyl chloride-vinyl isopropyl ether copolymer made by BASF ^b Made by Arakawa Chemical Industries

[0034]

[Table 3] Comparative Example Compounding amount (g) 1 2 3 4 5 6 Protease (B. subtilis)--8--8 Chitinase (Bacillus sp.)---5--Lysozyme (Chicken Egg White)--- -4-Larox MP-45 ^a -30 30 30 30 30 30 WW Rosin ^b -25 25 15 15 15 15 Cuprous oxide 5 ---- 10 Xylol 25 28 25 25 25 25 Methyl isobutyl ketone 15 17 15 15 15 15 ^a BASF vinyl chloride-vinyl isopropyl ether copolymer ^b Arakawa Chemical Industry Co., Ltd.

[0035]

[Table 4] Antifouling property (%) Example Immersion period (month) 1 2 3 4 5 6 7 8 9 10 11 12 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 4 0 0 0 0 0 0 0 0 0 0 0 0 6 0 0 0 0 0 0 0 0 0 0 0 0 12 0 0 0 0 0 0 0 0 0 5 5 0 0

[0036]

[Table 5]

[0037]

[Table 6]

[0038]

[Table 7]

[0039]

The present invention provides an antifouling coating composition which forms a coating film having excellent stability of enzymes in the coating material and coating film, and excellent antifouling property and durability.

Claims (4)

[Claims] 1. An antifouling coating composition containing a lipid-modifying enzyme solubilized in an organic solvent by modifying with a lipid having 6 to 30 carbon atoms and a coating resin. 2. The antifouling coating composition according to claim 1, wherein the lipid has a hydrophilic portion selected from the group consisting of sugar, phosphoric acid group, sulfonic acid group and ammonium salt. 3. The lipid has the formula: [In the formula, each R is independently a C _{6 to} C ₂₀ hydrocarbon group. ] The antifouling coating composition according to claim 1, which is represented by 4. The antifouling coating composition according to claim 1, wherein the enzyme is a proteolytic enzyme or a polysaccharide degrading enzyme.