Timber antiseptic agent

Abstract

To provide a timber antiseptic agent which exhibits superior safety and superior antibacterial performance with low influence on the human body and environment.SOLUTION: The present invention relates to a timber antiseptic agent containing an alkyl 4-hydroxybenzoate represented by formula (1) [where R represents an alkyl group having 5 to 10 carbon atoms] or a salt thereof.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a wood preservative having excellent antibacterial effect against wood-decaying fungi. [Background technology]

[0002] Wood is widely used as a material for buildings, furniture, and other items because it feels pleasant to the touch and is easy to obtain and recycle.

[0003] Particularly in recent years, there has been a call for the active utilization of artificial forests over 50 years old, whose carbon dioxide absorption capacity has decreased. In addition, the use of cross-laminated timber (a building material made by gluing thin slices of wood together so that the fibers cross each other) has significantly improved the fire resistance and earthquake resistance of wood, leading to the construction of high-rise wooden buildings, and the use of wood is on the rise.

[0004] However, in a hot and humid environment like Japan, wood is easily deteriorated by wood-rotting fungi over time, making it difficult to maintain buildings for a long time. Therefore, various wood preservatives and fungicides are used.

[0005] Chromium-copper-arsenic compound (CCA) wood preservatives once held an overwhelming share of the market as wood preservatives for pressure injection treatment, but their use has been declining due to concerns about their impact on the human body and the environment. Instead, water-soluble copper-based agents, such as copper-quaternary ammonium compound (ACQ) and copper-azole compound (CuAz), are being used.

[0006] Other proposed wood preservatives include a wood preservative containing an anionic surfactant containing a sulfonate or lauryl sulfate as an active ingredient (Patent Document 1), and a wood preservative containing 3'-isopropyl-2-trifluoromethylbenzoic acid anilide as an active ingredient (Patent Document 2).

[0007] In addition, it has been reported that lower alkylparabens such as n-propyl paraoxybenzoate (also known as propylparaben) and n-butyl paraoxybenzoate (also known as butylparaben) have antibacterial effects against basidiomycetes as wood preservatives (Patent Document 3). [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2007-015959 A [Patent Document 2] International Publication No. 2010 / 074129 [Patent Document 3] Japanese Patent Application Publication No. 11-217310 Summary of the Invention [Problem to be solved by the invention]

[0009] However, water-soluble copper-based agents contain metal ions that cannot be decomposed, and there are concerns about environmental problems if they are eluted. Furthermore, copper-resistant bacteria have been identified in recent years. In addition, other wood preservatives that have been used in the past have not been effective enough. In particular, lower alkyl parabens with four or less carbon atoms have low antibacterial effects against wood-rotting fungi or wood surface-contaminating fungi.

[0010] An object of the present invention is to provide a wood preservative that has little effect on the human body and the environment, is excellent in safety, and has excellent antibacterial effect.Another object of the present invention is to provide an antibacterial method against wood-decaying fungi and / or wood surface-contaminating fungi, which is also excellent in safety. [Means for solving the problem]

[0011] Means for Solving the Problems The present inventors conducted intensive research in view of the above problems and discovered that a specific 4-hydroxybenzoic acid ester or a salt thereof has a high antibacterial effect against wood-decaying fungi and / or wood surface-contaminating fungi, thereby completing the present invention.

[0012] That is, the present invention includes the following preferred embodiments. [1] Formula (1) [ka] [In the formula, R represents an alkyl group having 5 to 10 carbon atoms] A wood preservative comprising an alkyl 4-hydroxybenzoate represented by the formula: [2] The wood preservative according to [1], wherein the alkyl 4-hydroxybenzoate is hexyl 4-hydroxybenzoate and / or 2-ethylhexyl 4-hydroxybenzoate. [3] The wood preservative according to [1] or [2], wherein the alkyl 4-hydroxybenzoate is hexyl 4-hydroxybenzoate. [4] The wood preservative according to any one of [1] to [3], further comprising a solvent. [5] The wood preservative according to any one of [1] to [4], for inhibiting the proliferation of wood-decaying fungi and / or for inhibiting the proliferation of wood surface-contaminating fungi. [6] A wood preservative according to [5], wherein the wood-decaying fungus is Coriolus palustris and / or Coriolus versicolor. [7] The wood preservative according to [5], wherein the wood surface-contaminating fungus is a zygomycete. [8] A method for preserving wood, comprising applying the wood preservative according to any one of [1] to [7] to wood. [9] Wood treated with the wood preservative according to any one of [1] to [7]. Effect of the Invention

[0013] The wood preservative of the present invention can provide a high antibacterial effect against wood-decaying fungi. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] In the present invention, the wood preservative refers to an agent that exerts a preservative effect on wood by inhibiting the growth of wood-decaying fungi.

[0015] The wood preservative of the present invention contains, as an active ingredient, an alkyl 4-hydroxybenzoate represented by formula (1) or a salt thereof. [ka] [In the formula, R represents an alkyl group having 5 to 10 carbon atoms.]

[0016] The alkyl 4-hydroxybenzoate represented by formula (1) may be one or more selected from the group consisting of pentyl 4-hydroxybenzoate, hexyl 4-hydroxybenzoate, heptyl 4-hydroxybenzoate, octyl 4-hydroxybenzoate, 2-ethylhexyl 4-hydroxybenzoate, nonyl 4-hydroxybenzoate, and decyl 4-hydroxybenzoate. Hexyl 4-hydroxybenzoate and / or 2-ethylhexyl 4-hydroxybenzoate are preferred in terms of their excellent antibacterial effect against wood-rotting fungi, and hexyl 4-hydroxybenzoate is particularly preferred in terms of their excellent safety.

[0017] The salt of alkyl 4-hydroxybenzoate represented by formula (1) used in the present invention is preferably an alkali metal salt or alkaline earth metal salt of the alkyl 4-hydroxybenzoate. Specific examples of the alkali metal include one or more selected from the group consisting of sodium, potassium, and lithium, and specific examples of the alkaline earth metal include magnesium and / or calcium.

[0018] The alkyl 4-hydroxybenzoate or its salt represented by formula (1) used in the present invention may be a commercially available product, or may be, for example, a product obtained by reacting 4-hydroxybenzoic acid with an aliphatic alcohol in the presence of an acid catalyst, as described in Japanese Patent Application No. 2016-240132 previously proposed by the applicant of the present invention.

[0019] The concentration of the alkyl 4-hydroxybenzoate or its salt represented by formula (1) in the wood preservative of the present invention is preferably 0.001 to 50 mass%, more preferably 0.01 to 30 mass%, and even more preferably 0.1 to 20 mass%. When the alkyl 4-hydroxybenzoate or its salt is within the above concentration, the antibacterial effect against wood-decaying fungi is efficiently exerted.

[0020] The wood preservative of the present invention may contain, in addition to the alkyl 4-hydroxybenzoate represented by formula (1) or a salt thereof, other preservative components, solvents, surfactants, thickeners, pigments, resins, etc.

[0021] Other preservative components include iodine-based preservatives such as iodopropynyl butylcarbamate (IPBC), 3-bromo-2,3-diiodo-2-propynyl ethyl carbonate (EBIP), p-chlorophenyl-3-iodo-propargyl formal (CPIPF), and triazole compounds such as cyproconazole, tebuconazole, propiconazole, and hexaconazole.

[0022] Examples of the solvent include water, alcohol-based solvents, glycol-based solvents, glycol ether-based solvents, glycol ester-based solvents, ketone-based solvents, glyme-based solvents, and other special solvents.

[0023] Examples of the alcohol-based solvent include benzyl alcohol, n-butanol, isobutyl alcohol, 3-methoxy-3-methyl-1-butanol, and 3-methoxy-3-methyl-1-butyl acetate. Examples of the glycol-based solvent include ethylene glycol, diethylene glycol, triethylene glycol, and propylene glycol. Examples of the glycol ether-based solvent include methyl carbitol, ethyl carbitol, butyl carbitol, methyl triglycol, propylene glycol monomethyl ether, 1-methoxy-2-propanol, polyethylene glycol monomethyl ether, propylene glycol monobutyl ether, 3-methoxy-3-methyl-1-butanol, and dipropylene glycol methyl ether. Examples of the glycol ester-based solvent include ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, diethylene glycol monobutyl ether acetate, and diethylene glycol monoethyl ether acetate. Examples of the glyme-based solvent include dipropylene glycol dimethyl ether, triethylene glycol dimethyl ether, diethylene glycol dimethyl ether, and triethylene glycol dimethyl ether. Ketone solvents include diacetone alcohol, cyclohexanone, and isophorone. Other special solvents include 1,3-dimethyl-2-imidazolidinone (DMI), N-butylpyrrolidone (NBP), N-dimethyl fatty acid amide, and dibasic acid ester (DBE).

[0024] The surfactant may, for example, be a nonionic surfactant, an anionic surfactant, or a cationic surfactant.

[0025] Examples of the nonionic surfactant include polyoxyethylene polycyclic phenyl ether, polyoxyethylene distyrenated phenyl ether, polyoxyethylene tristyrenated phenyl ether, polyoxyethylene tribenzyl phenyl ether, polyoxyalkylene polystyryl phenyl ether, and polyoxyethylene lauryl phenyl ether.

[0026] Examples of the anionic surfactant include calcium dodecylbenzenesulfonate, sodium dodecylbenzenesulfonate, polyoxyethylene styrenated phenyl ether sulfate, polyoxytridecyl ether phosphate, and polyoxyethylene alkyl (C8) ether phosphate.

[0027] Examples of cationic surfactants include benzalkonium chloride, coconut amine acetate, benzethonium chloride, NN didecyl NN-dimethyl ammonium chloride (DDAC), NN didecyl N-methyl polyoxyethyl ammonium propionate (DMPAP), and didecyl dimethyl ammonium methyl sulfate.

[0028] The thickener is used for the purpose of improving workability by adjusting the viscosity or preventing precipitation of the drug during storage. Examples of the thickener include known thickeners such as urethane-based thickeners, acrylic-based thickeners, cellulose-based thickeners, and clay minerals such as bentonite.

[0029] Examples of pigments include inorganic pigments (white pigments such as titanium oxide, yellow pigments such as titanium yellow, red pigments such as iron oxide red, green pigments such as chrome green, blue pigments such as cobalt blue, and black pigments such as carbon black), organic colorants (azo dyes and pigments, phthalocyanine dyes and pigments, lake dyes and pigments, etc.), extender pigments (calcium carbonate, barium sulfate, aluminum hydroxide, mica, talc, alumina, bentonite, magnesium oxide, etc.), and gloss pigments (metal foils such as stainless steel flakes, metal powders such as aluminum powder and zinc powder, etc.).

[0030] As the resin, either a thermoplastic resin or a thermosetting resin can be used, and examples of the thermoplastic resin include emulsion resins such as polyvinyl alcohol (PVA), polyvinyl acetate-polyvinyl alcohol (poval), ethylene-vinyl acetate (EVA), polycarbonate resin, acrylic resin, methacrylic resin, polyamide resin, polyester resin (e.g., polyalkylene terephthalate resin), polyurethane resin, etc. Examples of the thermosetting resin include phenol resin, urea resin, melamine resin, unsaturated polyester resin, silicone resin, alkyd resin, epoxy resin, etc.

[0031] The antibacterial targets of the wood preservative of the present invention are not particularly limited, and include, for example, wood-rotting fungi and molds as surface-contaminating fungi of wood. Wood-rotting fungi are generally known to decompose the main components of wood, such as cellulose, hemicellulose, and lignin, but are not particularly limited as long as they are fungi generally known as wood-rotting fungi, such as white-rot fungi and brown-rot fungi. Specific examples of basidiomycetes include the genera Fomitopsis, Trametes, Coniophora, Postia, Poria, Gloeophyllum, Lentinus, Paxillus, Pleurotus, Donkioporia, Serpula, Glenospora, Perenniporia, and Antrodia.

[0032] The wood preservative of the present invention has an inhibitory effect on the growth of mold that grows on wood and usually grows on its surface, in addition to the above-mentioned wood-decaying fungi. Examples of mold that grows on wood include zygomycetes such as those of the genera Mucor and Rhizopus.

[0033] In the present invention, the method for evaluating the preservative effect is as described in the Examples.

[0034] Methods for applying the wood preservative of the present invention to wood include coating methods, dipping methods, impregnation methods, and the like.

[0035] Examples of the coating method include painting with a brush, roll coating, and spray coating (eg, air spray, airless spray coating, etc.).

[0036] As the immersion method, it is preferable to completely immerse the wood in a bath containing a wood preservative for a period of several seconds to several minutes.

[0037] Impregnation methods include vacuum process, double vacuum process, vacuum-pressure process, and pressure injection process. It is preferable to use the pressure process to distribute the wood preservative relatively uniformly and deeply.

[0038] After application to wood, the wood preservative of the present invention can be dried at room temperature (for example, 15 to 25° C.) or by heating (for example, heating at 50 to 100° C.).

[0039] The wood preservative of the present invention may be used as an undercoat agent so as to come into direct contact with wood, or may be applied as a topcoat agent or intermediate coat agent onto a coating layer previously formed on wood.

[0040] Examples of wood to which the wood preservative is applied include building structures, transportation equipment, bridges, sign boards, markers, wooden products, etc. The wood preservative of the present invention is also effective for composite materials of wood and resin, and composite materials of wood and metal. The species of the wood is not particularly limited, and examples thereof include ash, ash, cedar, Yezo pine, pine, fir, Yezo pine, and wood containing a mixture of pine and fir (SPF wood).

[0041] The present invention also relates to wood treated with the wood preservative. The wood of the present invention is resistant to decay fungi and can maintain its strength and appearance for a long period of time. The present invention also covers wood products made of the wood, such as architectural structures, transportation equipment, bridges, signboards, indicators, woodwork, etc. The present invention also covers composite materials of the wood and resin, and composite materials of the wood and metal.

[0042] The present invention will be described in detail below with reference to examples, but the present invention is not limited thereto. EXAMPLES

[0043] <Test target fungi> Fungus 1: Fomitopsis palustris NBRC30339, Fomitopsis spp. Fungi 2: Trametes versicolor NBRC30340, Trametes genus Fungi 3: Rhizopus oryzae NBRC31005, Rhizopus spp.

[0044] [Example 1] 0.02 g of hexyl 4-hydroxybenzoate (Ueno Pharmaceutical Co., Ltd.), 500 μL of dimethyl sulfoxide (DMSO), and 9.48 mL of sterile water 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: 2000 μg / mL).

[0045] 180 μL of the pre-adjusted solution was added to each well in the first row from the left of a 96-well (12 rows x 8 columns) microplate, and 90 μL of sterile water was added to each well in the second to eleventh rows from the left. Next, 90 μL was taken from the well in the first row from the left and poured into the well next to it on the right, and diluted to 1 / 2. This operation was repeated from the second row onwards, and a solution containing hexyl 4-hydroxybenzoate at a concentration of 1000 to 2 μg / mL was prepared in the 96-well microplate. In addition, only 90 μL of sterile water was poured into the remaining wells to serve as blanks.

[0046] After sterilizing the prepared medium (malt extract 1g, peptone 0.5g, glucose 2.5g, potassium dihydrogen phosphate 0.3g, magnesium sulfate 0.2g, ion-exchanged water 44.4mL), 80μL was dispensed into each well. Next, the test fungus was cultured in the prepared medium at 30℃ for 20 hours, and the bacterial solution was poured into 10 3 A suspension diluted with saline to cfu / mL was added to each well at 10 μL, and then cultured at 30°C for 48 hours. After visually confirming that the test bacteria had grown in the blank, the growth of the test bacteria in each well was visually observed, and the minimum inhibitory concentration (MIC: μg / mL) was measured. The results are shown in Table 1. The minimum inhibitory concentration was measured according to the standard method of the Japanese Society of Chemotherapy (broth microdilution method).

[0047] [Example 2] The minimum inhibitory concentration was calculated in the same manner as in Example 1, except that hexyl 4-hydroxybenzoate was changed to 2-ethylhexyl 4-hydroxybenzoate (manufactured by Ueno Pharmaceutical Co., Ltd.). The results are shown in Table 1.

[0048] [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 butyl 4-hydroxybenzoate (manufactured by Ueno Pharmaceutical Co., Ltd.). The results are shown in Table 1.

[0049] [Comparative Example 2] 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 (manufactured by Ueno Pharmaceutical Co., Ltd.). The results are shown in Table 1.

[0050] As is clear from Table 1, it is understood that the 4-hydroxybenzoic acid esters represented by formula (1) (Examples 1 and 2) have excellent fungal growth inhibitory effects and are useful as wood preservatives. On the other hand, butyl 4-hydroxybenzoate (Comparative Example 1) and hexadecyl 4-hydroxybenzoate (Comparative Example 2) had low fungal growth inhibitory effects.

[0051]

Table 1

Claims

1. Formula (1) 【Chemistry 1】 [wherein R represents an alkyl group having 5 to 10 carbon atoms] The present invention relates to a wood preservative comprising an alkyl 4-hydroxybenzoate represented by the following formula:

2. 2. The wood preservative according to claim 1, wherein the alkyl 4-hydroxybenzoate is hexyl 4-hydroxybenzoate and / or 2-ethylhexyl 4-hydroxybenzoate.

3. 2. The wood preservative of claim 1, wherein the alkyl 4-hydroxybenzoate is hexyl 4-hydroxybenzoate.

4. The wood preservative of claim 1 further comprising a solvent.

5. 2. The wood preservative according to claim 1, for inhibiting the proliferation of wood-decaying fungi and / or for inhibiting the proliferation of wood surface-contaminating fungi.

6. 6. The wood preservative according to claim 5, wherein the wood-decaying fungus is Coriolus palustris and / or Coriolus versicolor.

7. The wood preservative according to claim 5, wherein the wood surface-contaminating fungus is a zygomycete.

8. A method for preserving wood, comprising applying the wood preservative according to any one of claims 1 to 7 to wood.

9. Wood treated with the wood preservative according to any one of claims 1 to 7.

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