JP7533930B2 - Biocides - Google Patents

Description

The present invention relates to a biocide that can be used as a wood preservative to protect wood from organisms that cause wood deterioration.

Wood-based materials (which refer to lumber, laminated lumber, laminated veneer lumber (LVL), etc., hereafter sometimes referred to as "wood") are used in a variety of places, from residential building materials such as foundations and pillars to landscaping fixtures such as decks and signs. However, wood-based materials are susceptible to biological deterioration due to wood-damaging pests such as termites and rotting, and if such biological deterioration occurs in a home, it could cause serious damage if it coincides with a natural disaster such as an earthquake.

For this reason, wood-based materials may be subjected to preservation treatments to protect them from decay and biological deterioration by termites and other insects. Biocides are used in preservation treatments, and preservation treatments can be carried out using methods such as painting, spraying, and immersion, which are surface treatments for wood-based materials, as well as pressurized injection, which can treat the interior of wood-based materials.

When a biocide is made to penetrate deep into wood using methods such as pressurized injection, if the biocide is colorless, it is not possible to determine the degree of penetration. Therefore, in order to make it possible to determine the degree of penetration of the biocide, a colorless marker that can change color through a chemical reaction is sometimes added as a secondary ingredient to the biocide. Zinc carboxylate, a typical marker, can be made to change color red when used with indicators such as dithizone or PAN, and this principle is used to color the areas in wood materials where the biocide has penetrated.

However, when a biocide contains zinc carboxylate and the insecticidal component pyrethroid, the pyrethroid may be decomposed by the effect of the zinc carboxylate. Such biocides have the disadvantage that they are difficult to store for long periods of time, and if stored for long periods of time, the biocidal effect is no longer expected.

In response to this, Patent Document 1 describes a method of preventing the decomposition of pyrethroids by adding a carboxylic acid to a biocide consisting of a glycol ether and zinc carboxylate.

JP 2018-087151 A

However, adding carboxylic acids to biocides poses the problem of increased irritation to the skin and eyes during preservation treatment of wood materials.

The present invention focuses on the above-mentioned problems and aims to provide a biocide that contains zinc carboxylate and pyrethroid, and has low irritation properties that inhibits the decomposition of pyrethroid even without containing carboxylic acid.

The inventors have investigated various means for solving the above problems and have found that by using glycol ether acetate as a solvent instead of glycol ether, a biocide containing zinc carboxylate and pyrethroid can be obtained that is less irritating and inhibits the decomposition of pyrethroid even in a biocide containing no carboxylic acid, even though the biocide does not contain carboxylic acid. As described in Patent Document 1, glycol ether cannot inhibit the decomposition of bifenthrin unless octylic acid is added, so a less irritating biocide cannot be obtained.

To solve the above problems, the biocide of the present invention contains a pyrethroid, a zinc carboxylate, and a glycol ether acetate.

The mass ratio of the pyrethroid, the glycol ether acetate, and the zinc carboxylate may be 1:40-60:1-40.

The pyrethroid may contain at least one selected from bifenthrin, permethrin, cyphenothrin, etofenprox, silafluofen, allethrin, alphamethrin, empenthrin, profluthrin, tefluthrin, tralomethrin, metofluthrin, fenothrin, imiprothrin, phthalthrin, pyrethrins, prallethrin, furamethrin, dimefluthrin, profluthrin, tefluthrin, bioallethrin, esbiothrin, bioresmethrin, cycloprothrin, cyfluthrin, decamethrin, cyhalothrin, cypermethrin, cyphenothrin, deltamethrin, tefluthrin, resmethrin, fenpropathrin, fenfluthrin, fenvalerate, flucythrinate, flumuthrin, fluvalinate, and resmethrin.

The zinc carboxylate may contain at least one selected from zinc 2-ethylhexanoate, zinc naphthenate, and zinc versatate.

The glycol ether acetate may contain at least one selected from ethylene glycol methyl ether acetate, ethylene glycol ethyl ether acetate, ethylene glycol butyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol ethyl ether acetate, propylene glycol methyl ether acetate, propylene glycol diacetate, dipropylene glycol methyl ether acetate, 1,3-butylene glycol diacetate, and 3-methoxybutyl acetate.

According to the present invention, it is possible to provide a biocide that contains zinc carboxylate and pyrethroid, and that is less irritating because it inhibits the decomposition of the pyrethroid even though it does not contain carboxylic acid.

The biocide according to the present invention will be described below. Note that the present invention is not limited to the following examples.

[Biocides]
The biocide of the present invention contains pyrethroid, zinc carboxylate, and glycol ether acetate, but does not contain carboxylic acid or glycol ether. Carboxylic acid is not preferred because it causes irritation to the skin and eyes during preservation treatment of wood materials. In addition, glycol ether can suppress the decomposition of pyrethroid in the presence of zinc carboxylate when used in combination with carboxylic acid, but the inclusion of glycol ether acetate makes carboxylic acid and glycol ether unnecessary.

(Pyrethroid)
Pyrethroid is a general term for the active ingredient contained in Tanacetum cinerariifolium (Trevir.) Sch. Bip., and various derivatives have been synthesized and are widely used as insecticides in various countries. In the present invention, pyrethroid is the main ingredient of the biocide.

For example, pyrethroids include bifenthrin, permethrin, cyphenothrin, etofenprox, silafluofen, allethrin, alphamethrin, empenthrin, profluthrin, tefluthrin, tralomethrin, metofluthrin, fenothrin, imiprothrin, phthalthrin, pyrethrins, prallethrin, furamethrin, dimefluthrin, profluthrin, tefluthrin, bioallethrin, esbiothrin, bioresmethrin, cycloprothrin, cyfluthrin, decamethrin, cyhalothrin, cypermethrin, cyphenothrin, deltamethrin, tefluthrin, resmethrin, fenpropathrin, fenfluthrin, fenvalerate, flucythrinate, flumuthrin, fluvalinate, and resmethrin.

The biocide of the present invention can contain at least one selected from these pyrethroids.

(Zinc carboxylate)
In order to make it possible to determine the degree of penetration of a biocide, a colorless marker that can develop a color through a chemical reaction may be added as a subcomponent of the biocide. Zinc carboxylate is a typical marker, and can be colored red by an indicator such as dithizone or PAN. Using this principle, the area of penetration of the biocide in wood materials can be colored.

For example, zinc carboxylates include zinc 2-ethylhexanoate, zinc naphthenate, and zinc versatate.

The biocide of the present invention can contain at least one selected from these zinc carboxylates.

(Glycol Ether Acetate)
Glycol ether acetates can inhibit the decomposition of pyrethroids in the presence of zinc carboxylates.

For example, glycol ether acetates include ethylene glycol methyl ether acetate, ethylene glycol ethyl ether acetate, ethylene glycol butyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol ethyl ether acetate, propylene glycol methyl ether acetate, propylene glycol diacetate, dipropylene glycol methyl ether acetate, 1,3-butylene glycol diacetate, and 3-methoxybutyl acetate.

The biocide of the present invention may contain at least one selected from these glycol ether acetates.

(Mass ratio of each component)
Unlike glycol ether, the biocide of the present invention can add zinc carboxylate at any ratio without worrying about the decomposition of pyrethroid if it is glycol ether acetate. Therefore, the mass ratio of pyrethroid, glycol ether acetate, and zinc carboxylate can be adjusted to any ratio. For example, the biocide of the present invention preferably has a mass ratio of pyrethroid, glycol ether acetate, and zinc carboxylate of 1:40 to 60:1 to 40. At this mass ratio, glycol ether acetate can sufficiently suppress the decomposition of pyrethroid in the presence of zinc carboxylate. If the mass ratio is outside this range, there is a risk that the decomposition of pyrethroid cannot be sufficiently suppressed, or the raw material cost of the biocide may be high.

(Other configurations)
In addition to pyrethroids, zinc carboxylates, and glycol ether acetates, the present invention may include other components, such as naphthenic solvents, that facilitate the impregnation of wood products with biocides.

The present invention may also include preservative components, insect repellent components, dyes, food colors, pigments, ultraviolet absorbers such as triazine-based ultraviolet absorbers, light stabilizers (HALS), antioxidants, metal soaps, mildew-proofing materials, flame retardants, coating agents, water repellents, resin components such as alkyd resins, kerosene, isoparaffin-based solvents, fluorine-based solvents, kerosene and isoparaffin-based solvents, bromine-based solvents, chlorine-based solvents such as dichloromethane, carbon dioxide in a subcritical or supercritical state, etc.

For example, examples of preservative ingredients include those commonly used as preservative ingredients for wood. Specific examples include quaternary ammonium salts such as didecyldimethylammonium chloride and benzalkonium chloride, triazole compounds such as cyproconazole, tebuconazole, propiconazole, difenoconazole, and epoxyconazole, organic zinc compounds such as zinc naphthenate, zinc versatate, and 2-ethylhexanoic acid, and iodine compounds such as butylcarbamate iodide propynyl and diiodomethyl paratolylsulfone.

In addition, examples of insect repellent ingredients include ingredients that are generally used as insect repellents for wood. Specific examples include neonicotinoid compounds such as imidacloprid and acetamiprid, phenylpyrazole compounds such as fipronil and pyriprole, chlorfenapyr, and broflanilide.

The present invention will be described in more detail below using examples, but the present invention is not limited to the following examples.

<Production of biocides>
In order to verify that in a biocide containing zinc carboxylate and pyrethroid, the coexistence of glycol ether acetate suppresses decomposition of the pyrethroid even in the absence of carboxylic acid, the biocides of Examples 1 to 6 and Comparative Examples 1 to 6 were produced by putting raw materials into a container and stirring them according to the formulation shown in Table 1.

Here, bifenthrin was used as the pyrethroid, zinc 2-ethylhexanoate as the zinc carboxylate, dipropylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, and diethylene glycol monobutyl ether acetate as the glycol ether acetates, tripropylene glycol monomethyl ether, dipropylene glycol monomethyl ether, and diethylene glycol monobutyl ether as the glycol ethers, 2-ethylhexanoic acid as the carboxylic acid, and a naphthenic solvent as the solvent.

The naphthenic solvent used was a petroleum-based hydrocarbon with a boiling point in the range of 140°C to 350°C.

<Verification of pyrethroid decomposition inhibition effect>
The initial content of bifenthrin was confirmed for the biocides of Examples 1 to 6 and Comparative Examples 1 to 6 prepared according to the formulations shown in Table 1, and then these were placed in a screw bottle and stored in a thermostatic chamber at a temperature condition of 50°C or 60°C for one month. After one month, the screw can was removed from the thermostatic chamber and allowed to cool to room temperature, and the content of bifenthrin was measured by high performance liquid chromatography (HPLC). The residual rate of bifenthrin was calculated by comparing with the initial content of bifenthrin. Table 2 shows the residual rate of bifenthrin for each biocide. If the residual rate of bifenthrin is 85% by mass or more in a heat resistance test at 60°C for one month, it is a pyrethroid concentration that does not cause any practical problems.

The results of Examples 1 to 6 clearly show that in biocides containing zinc carboxylate and pyrethroid, the coexistence of glycol ether acetate inhibits the decomposition of pyrethroid even in the absence of carboxylic acid. In particular, when dipropylene glycol monomethyl ether acetate or propylene glycol monomethyl ether acetate was used as the glycol ether acetate, the pyrethroid was not decomposed at all.

On the other hand, in Comparative Examples 1 to 6, pyrethroids were decomposed unless carboxylic acids, which may cause skin or eye irritation, were used in the preservation treatment of wood materials.

From the above results, it is clear that the present invention can provide a biocide that contains zinc carboxylate and pyrethroid, and that has low irritation and inhibits the decomposition of pyrethroid even though it does not contain carboxylic acid.

Claims (4)

Pyrethroids and
Zinc carboxylate,
glycol ether acetate ,
A biocide containing, as the pyrethroid, at least one selected from bifenthrin, permethrin, etofenprox, silafluofen, allethrin, empenthrin, profluthrin, tefluthrin, metofluthrin, fenothrin, imiprothrin, phthalthrin, pyrethrins, prallethrin, furamethrin, dimefluthrin, esbiothrin, bioresmethrin, tefluthrin, resmethrin, and resmethrin. The biocide according to claim 1, wherein the mass ratio of the pyrethroid, the glycol ether acetate, and the zinc carboxylate is 1:40-60:1-40. 3. The biocide according to claim 1 or 2 , wherein the zinc carboxylate is at least one selected from the group consisting of zinc 2-ethylhexanoate, zinc naphthenate, and zinc versatate. The biocide according to any one of claims 1 to 3, wherein the glycol ether acetate is at least one selected from the group consisting of ethylene glycol methyl ether acetate, ethylene glycol ethyl ether acetate, ethylene glycol butyl ether acetate, diethylene glycol monobutyl ether acetate , diethylene glycol ethyl ether acetate, propylene glycol methyl ether acetate, dipropylene glycol methyl ether acetate , and 3 - methoxybutyl acetate.