Algae-resistant coatings

Abstract

To provide an algicidal coating having excellent safety and high algicidal effect.SOLUTION: This invention relates to an algicidal coating containing 4-hydroxy benzoate represented by formula (1) [where R1 is a hydrogen atom or an alkali metal, R2 is a C1 to 22 alkyl group or an aryl group].SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an anti-algae paint that is highly effective in controlling algae or preventing the growth of algae. [Background technology]

[0002] Algae have traditionally caused various types of damage to underwater reefs, artificial structures (ships, fishing nets, underwater structures, seawater intake pipes, buoys, etc.), and the exterior walls of houses, etc. For example, damage has been reported in fishing nets, such as a loss of commercial value due to the growth of weeds in cultivated seaweed, a decrease in sailing speed and an increase in fuel consumption due to the growth of algae and barnacles on the bottom of ships, and the occurrence of foul odors and unpleasant smells in homes, as well as a significant loss of aesthetic appeal.

[0003] As a countermeasure against damage caused by these organisms, various methods are known in which paints containing antifouling agents, algicides, and anti-algae agents are applied to various facilities, materials, etc. For example, there have been proposed paints containing antifouling agents blended with organic antibacterial agents such as organic triazine compounds and quaternary ammonium compounds (Patent Documents 1 and 2), and antifouling agents blended with inorganic metal compounds such as cuprous oxide, copper powder, copper thiocyanate, copper carbonate, copper chloride, copper sulfate, zinc oxide, zinc sulfate, nickel sulfate, and copper-nickel alloys, and organometallic compounds such as organotin compounds, organocopper compounds, organonickel compounds, and organozinc compounds (Patent Document 3). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 9-241544 [Patent Document 2] Japanese Patent Application Publication No. 10-287511 [Patent Document 3] Japanese Patent Application Publication No. 5-112739 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the compounds described in Patent Documents 1 to 3 are considered problematic due to their adverse effects on the human body and environmental pollution, and are therefore undesirable for practical use. In light of this background, there has been a demand for the development of an anti-algae paint that has minimal impact on the human body and the environment and has excellent anti-algae effects.

[0006] An object of the present invention is to provide an anti-algae paint that has little impact on the human body and the environment, is excellent in safety, and has a high anti-algae effect.Another object of the present invention is to provide an anti-algae method that has excellent safety and has a high anti-algae effect. [Means for solving the problem]

[0007] As a result of intensive research in light of the above problems, the present inventors discovered that paints containing specific 4-hydroxybenzoic acid esters have a high anti-algae effect against algae such as chlorella and Nostoc, and thus completed the present invention.

[0008] That is, the present invention includes the following preferred embodiments. [1] Formula (1) [ka] [wherein R1 represents a hydrogen atom or an alkali metal, and R2 represents an alkyl group or an aryl group having 1 to 22 carbon atoms] An anti-algae paint containing a 4-hydroxybenzoic acid ester represented by the formula: [2] The anti-algae paint according to [1], wherein in the formula (1), R1 represents a hydrogen atom. [3] The anti-algae paint according to [1] or [2], wherein R2 is an alkyl group or an aryl group having 5 to 22 carbon atoms. [4] The anti-algae coating material according to any one of [1] to [3], wherein in the formula (1), R2 represents an alkyl group or an aryl group having 6 to 18 carbon atoms. [5] The anti-algae coating material according to any one of [1] to [4], wherein in the formula (1), R2 represents an alkyl group. [6] The anti-algae paint according to any one of [1] to [5], wherein the 4-hydroxybenzoic acid ester represented by formula (1) is one or more selected from the group consisting of hexyl 4-hydroxybenzoate, ethylhexyl 4-hydroxybenzoate, and hexadecyl 4-hydroxybenzoate. [7] A method for controlling algae or preventing the growth of algae, comprising applying the anti-algae paint according to any one of [1] to [6] to a treatment area or object where algae can grow. [Effects of the Invention]

[0009] According to the present invention, it is possible to obtain an anti-algae paint that is excellent in safety and has a high anti-algae effect against algae. DETAILED DESCRIPTION OF THE INVENTION

[0010] The anti-algae paint of the present invention contains a 4-hydroxybenzoic acid ester represented by formula (1). [ka] [In the formula, R1 represents a hydrogen atom or an alkali metal, and R2 represents an alkyl group or aryl group having 1 to 22 carbon atoms.]

[0011] When R1 represents an alkali metal, examples of the alkali metal include sodium, potassium, and lithium. R1 is preferably a hydrogen atom.

[0012] R2 preferably represents an alkyl group or an aryl group, more preferably an alkyl group, and the alkyl group or aryl group preferably has 5 to 22 carbon atoms, more preferably has 6 to 18 carbon atoms, and even more preferably has 6 to 16 carbon atoms.

[0013] Examples of the 4-hydroxybenzoic acid ester represented by formula (1) include methyl 4-hydroxybenzoate, ethyl 4-hydroxybenzoate, propyl 4-hydroxybenzoate, isopropyl 4-hydroxybenzoate, butyl 4-hydroxybenzoate, isobutyl 4-hydroxybenzoate, pentyl 4-hydroxybenzoate, hexyl 4-hydroxybenzoate, heptyl 4-hydroxybenzoate, octyl 4-hydroxybenzoate, ethylhexyl 4-hydroxybenzoate, nonyl 4-hydroxybenzoate, and 4-hydroxybenzoic acid decyl 4-hydroxybenzoate, undecyl 4-hydroxybenzoate, dodecyl 4-hydroxybenzoate, tridecyl 4-hydroxybenzoate, tetradecyl 4-hydroxybenzoate, pentadecyl 4-hydroxybenzoate, hexadecyl 4-hydroxybenzoate, heptadecyl 4-hydroxybenzoate, octadecyl 4-hydroxybenzoate, nonadecyl 4-hydroxybenzoate, icosyl 4-hydroxybenzoate, heneicosyl 4-hydroxybenzoate, and heneicosyl 4-hydroxybenzoate.

[0014] Among these, hexyl 4-hydroxybenzoate, heptyl 4-hydroxybenzoate, octyl 4-hydroxybenzoate, ethylhexyl 4-hydroxybenzoate, nonyl 4-hydroxybenzoate, decyl 4-hydroxybenzoate, undecyl 4-hydroxybenzoate, dodecyl 4-hydroxybenzoate, tridecyl 4-hydroxybenzoate, tetradecyl 4-hydroxybenzoate, and pentadecyl 4-hydroxybenzoate are particularly well-known for their superior anti-algae effects. Tadecyl, hexadecyl 4-hydroxybenzoate, heptadecyl 4-hydroxybenzoate, octadecyl 4-hydroxybenzoate, nonadecyl 4-hydroxybenzoate, eicosyl 4-hydroxybenzoate, heneicosyl 4-hydroxybenzoate and heneicosyl 4-hydroxybenzoate are preferably used, and particularly hexyl 4-hydroxybenzoate, ethylhexyl 4-hydroxybenzoate and hexadecyl 4-hydroxybenzoate are more preferably used.

[0015] The 4-hydroxybenzoic acid ester used in the present invention may be a commercially available product, or may be one obtained by reacting 4-hydroxybenzoic acid with an aliphatic alcohol in the presence of a catalyst, as described in JP-A-2018-95581 and JP-A-2016-210699.

[0016] The anti-algae paint of the present invention is prepared by blending the 4-hydroxybenzoic acid ester represented by formula (1) with components typically used in paints, such as solvents, resins, pigments, and various additives.

[0017] Solvents include isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, butyl cellosolve, ethyl cellosolve, methyl ethyl ketone, methyl isobutyl ketone, xylene, and toluene.

[0018] Examples of the resin include alkyd resin, aminoalkyd resin, vinyl resin, acrylic resin, epoxy resin, urethane resin, unsaturated polyester resin, chlorinated rubber, and silicone.

[0019] Examples of pigments include white pigments such as titanium dioxide, zinc oxide, zinc sulfide, lithopone, lead pigments, antimony oxide, zirconium oxide, and zircon; extender pigments such as hydrous magnesium aluminum silicate, calcium carbonate, barium sulfate, silicates, potassium aluminosilicate, and hydrated alumina; chromatic inorganic pigments such as iron oxide pigments, lead chromate, lead molybdate, cadmium pigments, synthetic metal oxides, and dark blue; specialty pigments and metallic pigments such as zinc yellow, basic zinc chromate, strontium chromate, red lead, copper(I) oxide, calcium plumbate, basic lead silicochromate, white molybdate, modified barium metaborate, zinc phosphate, and pearl essence.

[0020] The various additives include rust inhibitors, anti-sagging agents, wetting agents, reaction accelerators, anti-settling agents, etc., which can be appropriately blended as required.

[0021] These solvents, resins, pigments and various additives may be used alone or in combination of two or more.

[0022] The anti-algae paint of the present invention contains the 4-hydroxybenzoic acid ester represented by formula (1) as an essential component, but may also contain other anti-algae agents in combination depending on the purpose and application.

[0023] Other anti-algae agents that may be used in combination with 4-hydroxybenzoic acid esters include organic compounds such as organic pyridine compounds, organic triazine compounds, and quaternary ammonium compounds, organometallic compounds such as organotin compounds, organocopper compounds, organonickel compounds, and organozinc compounds, and inorganic metal compounds such as cuprous oxide, copper powder, copper thiocyanate, copper carbonate, copper chloride, copper sulfate, zinc oxide, zinc sulfate, nickel sulfate, and copper-nickel alloys. When other anti-algae agents are used in combination, it is preferable, from the standpoint of safety, that the amount (mass) of the agent used be equal to or less than the amount (mass) of the 4-hydroxybenzoic acid ester represented by formula (1) used.

[0024] In the anti-algae paint of the present invention, the content of the 4-hydroxybenzoic acid ester represented by formula (1) can be determined appropriately depending on the application method and application location, but it is preferable that the proportion of the 4-hydroxybenzoic acid ester represented by formula (1) in the paint is preferably 0.001 to 50 mass%, more preferably 0.01 to 40 mass%, and even more preferably 0.1 to 30 mass%.

[0025] The algae that can be controlled by the anti-algae paint of the present invention include indigo color Algae belonging to the phylum Plantae, Rhodophyta, Cryptophyta, Phaeophyta, Euglenophyta, Prasinophyta and subphylum Chlorophyta (e.g., algae belonging to classes such as Cyanobacteria, Euglenophyta, Chlorophyta, Diatoms, Prasinophyta, Rhodophyta and Phaeophyta), and specific examples include the following algae:

[0026] Cyanobacteria, including species of the genus Oscillatoria such as Oscillatoria laetevirens, and species of the genus Nostoc such as Nostoc commune. Euglena algae, including the genus Euglena, such as Euglena gracilis.

[0027] Green algae including the genus Chlorella such as Chlorella vulgaris, the genus Chlamydomonas such as Chlamydomonas reinhardtii, and the genus Ulothrix such as Ulothrix variabilis.

[0028] Diatoms including the genera Eolimna, such as Eolimna minima, Gomphonema, such as Gomphonema parvulum, Tabellaria, such as Tabellaria flocculosa, and Melosira, such as Melosira granulata.

[0029] Among these, the genera Oscillatoria, Nostoc, Chlorella, Eolimna, and Gomphonema are preferably used for algae control, and the genus Eolimna is more preferably used for algae control.

[0030] It is also effective against coelenterates such as hydra, sea anemones, and corals that live in symbiosis with or feed on the above-mentioned algae; tentacled animals such as bryozoans, bryozoans, bryozoans, and hydryozoans; arthropods such as vertical-striped barnacles, triangular barnacles, barnacles, red barnacles, barnacles, mud worms, shrimp, and crabs; annelids such as lugworms, turban shells, scale worms, sea squirts, and serpulid worms; mollusks such as Mytilus edulis, mussels, Pacific oysters, and golden mussels; protochordates such as ascidians, Ciona intestinalis, and red ascidians; and sponges such as purple sponges and sea sponges.

[0031] The anti-algae paint of the present invention can be applied to a treatment area or object where target organisms can grow, to control algae or prevent the growth of algae.

[0032] Examples of the area or object to be treated include ships (particularly the bottom of a ship), swimming pools, aquariums, fishing nets, seaweed nets, fishing cages, fishing tackle, underwater reefs, underwater structures, seawater inlet pipes, buoys, houses (particularly exterior walls, roofs, kitchens, washrooms, verandas, storerooms, etc.), flower pots, planters, the bottom or peripheral areas of seedling pots, drainage outlets, etc. The method can also be applied to organisms themselves that can serve as a nutrient source for algae, or the peripheral areas of such organisms.

[0033] The anti-algae paint of the present invention can be applied to the object to be treated by sprinkling, spraying, painting, or the like. [Example]

[0034] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. The anti-algae components A to D, the test algae 1 to 5, and the culture media used in the examples and comparative examples are shown below.

[0035] <Anti-algae ingredient> Anti-algae ingredient A: hexyl 4-hydroxybenzoate (Ueno Pharmaceutical Co., Ltd.) Anti-algae ingredient B: Ethylhexyl 4-hydroxybenzoate (Ueno Pharmaceutical Co., Ltd.) Anti-algae ingredient C: hexadecyl 4-hydroxybenzoate (Ueno Pharmaceutical Co., Ltd.) Anti-algae ingredient D: butyl 4-hydroxybenzoate (manufactured by Ueno Pharmaceutical Co., Ltd.) Anti-algae ingredient E: Phenoxyethanol (reagent: Fujifilm Wako Pure Chemical Industries, Ltd.)

[0036] <Test algae> Algae 1: Chlorella vulgaris NIES-2170 (C medium) Algae 2: Nostoc commune: Nostoc commune NIES-24 (medium used: MDM medium) Algae 3: Oscillatoria laetevirens NIES-31 (medium used: MDM medium) Algae 4: Eolimna minima: Eolimna minima NIES-2720 (Culture used: CSi medium) Algae 5: Gomphonema parvulum NIES-2723 (Chemical medium: CSi medium)

[0037] <Minimum inhibitory concentration of anti-algae ingredients> The minimum inhibitory concentration was measured using the standard method of the Japanese Society of Chemotherapy, with the exception that the bacteria was replaced with algae.

[0038] [Example 1] 0.04 g of hexyl 4-hydroxybenzoate, 500 μL of dimethyl sulfoxide (DMSO), and 9.46 mL of medium were added to a sample tube and stirred for 1 minute using a vortex mixer to prepare a pre-prepared solution (hexyl 4-hydroxybenzoate concentration: 4000 μg / mL). 12 test tubes were prepared for each test algae, and 3 mL of the pre-prepared solution was added to the leftmost test tube, and 1.5 mL of medium was added to the remaining test tubes.

[0039] 1.5 mL of the pre-prepared solution was taken from the leftmost test tube and poured into the adjacent test tube, and stirred for 30 seconds in a vortex mixer. 1.5 mL was then taken from that tube and poured into the adjacent test tube. This process was repeated until a two-fold diluted solution was prepared in each test tube until the hexyl 4-hydroxybenzoate concentration reached 2 μg / mL.

[0040] 1.4 mL of medium and 100 μL of the test algae suspension were added to each test tube, and the algae were cultured at 25°C for 40 days under 1000 lux illumination for 16 hours per day. The growth of the algae after culture was observed, and the minimum inhibitory concentration (MIC: μg / mL) was calculated. The results are shown in Table 1.

[0041] [Example 2] (Example for reference) The minimum inhibitory concentration was calculated in the same manner as in Example 1, except that hexyl 4-hydroxybenzoate was changed to ethylhexyl 4-hydroxybenzoate. The results are shown in Table 1.

[0042] [Example 3] The minimum inhibitory concentration was calculated in the same manner as in Example 1, except that hexyl 4-hydroxybenzoate was changed to hexadecyl 4-hydroxybenzoate. The results are shown in Table 1.

[0043] [Example 4] (Example for reference) The minimum inhibitory concentration was calculated in the same manner as in Example 1, except that butyl 4-hydroxybenzoate was used instead of hexyl 4-hydroxybenzoate. The results are shown in Table 1.

[0044] [Comparative Example 1] The minimum inhibitory concentration was calculated in the same manner as in Example 1, except that hexyl 4-hydroxybenzoate was replaced with phenoxyethanol. The results are shown in Table 1.

[0045] As is clear from Table 1, the 4-hydroxybenzoic acid esters represented by formula (1) (Examples 1 to 4) have excellent algae growth inhibitory effects and are useful as anti-algae paints. On the other hand, phenoxyethanol (Comparative Example 1) had a low algae growth inhibitory effect.

[0046] [Table 1]

[0047] [Example 5] 1.0 g of hexyl 4-hydroxybenzoate was added to 9.0 g of urethane paint (manufactured by Washin Paint Co., Ltd.) to prepare an anti-algae paint containing 10% by mass of hexyl 4-hydroxybenzoate. The prepared paint was applied with a brush to the surface of a 540 x 430 x 0.4 mm polypropylene test piece, and the condition of the coating film after drying was observed. No particles or separated layers of hexyl 4-hydroxybenzoate were observed, and the coating film was problem-free. In this way, a coating film capable of controlling algae or preventing their growth was obtained.

[0048] [Example 6] The coating film condition was observed in the same manner as in Example 5, except that the concentration of hexyl 4-hydroxybenzoate in the paint was changed to 5% by mass, but no particles or separated layers of hexyl 4-hydroxybenzoate were observed, and the coating film was problem-free. In this way, a coating film capable of controlling algae or preventing the growth of algae was obtained.

[0049] [Example 7] The coating film condition was observed in the same manner as in Example 5, except that the concentration of hexyl 4-hydroxybenzoate in the paint was changed to 2% by mass, but no particles or separated layers of hexyl 4-hydroxybenzoate were observed, and the coating film was problem-free. In this way, a coating film capable of controlling algae or preventing the growth of algae was obtained.

[0050] [Example 8] The coating film condition was observed in the same manner as in Example 5, except that the concentration of hexyl 4-hydroxybenzoate in the paint was changed to 0.5% by mass, but no particles or separated layers of hexyl 4-hydroxybenzoate were observed, indicating that the coating film was problem-free. Thus, a coating film capable of controlling algae or preventing the growth of algae was obtained.

[0051] [Example 9] The condition of the coating film was observed in the same manner as in Example 5, except that hexyl 4-hydroxybenzoate in the paint was changed to ethylhexyl 4-hydroxybenzoate, but no separation layer was observed, indicating that the coating film was problem-free. In this way, a coating film capable of controlling algae or preventing the growth of algae was obtained.

[0052] [Example 10] The condition of the coating film was observed in the same manner as in Example 5, except that hexyl 4-hydroxybenzoate in the paint was changed to hexadecyl 4-hydroxybenzoate, but no particles or separated layer of hexadecyl 4-hydroxybenzoate were observed, and the coating film was problem-free. In this way, a coating film capable of controlling algae or preventing their growth was obtained.

[0053] [Example 11] The condition of the coating film was observed in the same manner as in Example 5, except that hexyl 4-hydroxybenzoate in the paint was changed to butyl 4-hydroxybenzoate, but no particles or separation layer of butyl 4-hydroxybenzoate were observed, and the coating film was problem-free. In this way, a coating film capable of controlling algae or preventing their growth was obtained.

[0054] Comparative Example 2 The coating film condition was observed in the same manner as in Example 5, except that hexyl 4-hydroxybenzoate was replaced with phenoxyethanol, and a separated layer was confirmed in the coating film. Thus, a coating film capable of controlling algae or preventing the growth of algae could not be obtained.

Claims

1. Formula (1) 【Chemistry 1】 [In the formula, R １ represents a hydrogen atom or an alkali metal, and R ２ represents an alkyl group or an aryl group having 1 to 22 carbon atoms. The compound contains a 4-hydroxybenzoic acid ester represented by the formula: An anti-algae paint, wherein the 4-hydroxybenzoic acid ester represented by formula (1) is hexyl 4-hydroxybenzoate.

2. The anti-algae paint according to claim 1, wherein the algae to be controlled by the anti-algae paint is selected from the group consisting of algae belonging to the phylum Cyanobacteria and the subphylum Chlorophyta.

3. A method for controlling algae or preventing the growth of algae, comprising applying the anti-algae paint according to claim 1 or 2 to a treatment area or object where algae can grow.

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