DE3614909A1 - Methylene dirhodanide- and thiabendazole-containing wood preservatives - Google Patents

Abstract

Wood preservatives containing a mixture of methylene dirhodanide, thiabendazole, quaternary ammonium salt and acid.

Description

The present invention relates to wood preservatives, in particular for Protection of fresh wood, which is a mixture called methylenedirhodanide (Methylene bisthiocyanate, MBT), 2- (4-thiazolyl) benzimidazole (thiabendazole), contain a quaternary ammonium compound and an acid.

It is known that methylene bisthiocyanate as a fungicide against blue stain in Wood preservatives for the temporary protection of fresh, green wood in the forest or sawmill is used. Aqueous solutions or emulsions with one Content from 0.10 to 0.20% (wt .-%) give adequate protection against blueness over a period of about 3 to 6 months. The effectiveness against various molds and a. Aspergillus spp, Trichoderma spp, However, Penicillum spp is not sufficient. Under unfavorable climatic Conditions and at high infection pressure, starting from infected Wood, the protected wood is already in a few weeks surface mold discolored.

Thiabendazole has a good effectiveness against mold when used as a temporary wood preservative with an application concentration of 0.10-0.20% (emulsion or solution) will surface against that previously Protected molds, but the wood is protected by blue stains already faded after a few weeks.

It has now been found that the above disadvantages do not occur when a wood preservative based on a mixture of methylene bisthiocyanate, Thiabendazole, a quaternary ammonium compound and an acid used that, when diluted with water, an aqueous solution with a pH of 2 to 5, preferably 3 to 4.5. The content of methylenedirhodanide is, for example, 0.1 to 20%, preferably 4 to 15%, especially 6 to 10%. The thiabendazole content is, for example 0.1 to 20%, preferably 2 to 8%, in particular 4 to 6%. The acid content is, for example, 4 to 11%, preferably 5 to 10%, especially 6 to 9%. To dissolve the methylene bisthiocyanate water-dilutable organic solvents, e.g. B. dimethylformamide, Dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide and butyrolactone be used. The thiabendazole is mixed with an acid, e.g. B. 3-methoxypropionic acid, 2-methoxyacetic acid or hydroxycarboxylic acid, e.g. B. Lactic acid dissolved. The wood preservatives (concentrates) can additionally Contain water, if necessary with the acids or the quaternary Ammonium compounds are introduced into the wood preservative.  

The wood preservatives show a surprisingly good fungicidal effect in the Comparison to the individual active ingredients. It is also surprising that the Thiabendazole stable at pH values from 2 to 5, especially 3 to 4.5 is.

The wood preservatives (concentrates) contain, for example:
0.1-20% MBT
0.1-20% thiabendazole
5-90% quaternary ammonium compound
4-11% acid,
where the sum is 100% (wt .-%) and minor amounts of other components such as corrosion inhibitors and, if necessary, water, the proportion of which, however, i. A. can be kept low and is essentially used for handling. However, the invention extends equally to the solutions which can be prepared by dilution with water and correspondingly lower individual concentrations. These are called aqueous solutions of e.g. B. 0.1-10% (calculated on the concentrate) used.

As quaternary ammonium compounds such. B. those are used which correspond to the general formula (R ¹ R ² R ³ R ⁴ N) ⁺Z ^- ,
R ¹ denotes an alkyl radical with 8 to 20 carbon atoms, an alkenyl radical with 12 to 20 carbon atoms or a benzyl radical which is optionally substituted by C ₁ -C ₂₀ alkyl or halogen,
R ² C ₁ -C ₆ alkyl, C ₃ -C ₉ alkoxyalkyl or C ₁ -C ₄ alkoxy
R ^{3 is} C ₁ -C ₆ alkyl or C ₁ -C ₄ alkoxy
R ⁴ C ₁ -C ₂₀ alkyl or C ₁ -C ₄ alkoxy
mean, or two of the radicals R ¹ to R ⁴ together with the nitrogen atom form a heterocyclic radical which contains 4 to 5 C atoms, 1 to 2 N atoms and one, two or three double bonds, the carbon atoms optionally being substituted by C ₁ -C ₄ alkyl or halogen are substituted, and Z represents an acid residue.

The concentrates are clear, more or less viscous solutions Water form clear aqueous solutions and depending on the application concentration and hardness of the water a pH of 2 to 5, preferably 3 to 4.5 have.  

By adding suitable corrosion inhibitors, e.g. B. isononanoic acid the corrosion behavior can be improved.

The invention is illustrated by the following examples.

Test execution

Freshly cut pine sapwood boards (20 × 5 × 1.5 cm ³ ; relative wood moisture more than 60%) were immersed in the aqueous solutions of the wood preservatives (1 minute) and placed on plastic pipes (1 cm in diameter) directly on a freshly cut lawn (hereby an optimal infestation pressure is achieved by blue stain and mold). 10 boards were impregnated and assessed after 3 or 6 months of weathering (May to October).

Example A (comparison)

Thiabendazole water soluble
20% thiabendazole 60% lactic acid 20% phenylglycol

This gives you a clear, viscous liquid that is complete is water soluble.

Example B (comparison)

10% methylene bisthiocyanate 10% butyl glycol acetate (CH ₃ COOCH ₂ CH ₂ OC ₄ H ₉ ) 60% benzalkonium chloride (C ₁₂ -C ₁₆ ) (N-benzyl, N, N-dimethyl, NC ₁₂ -C ₁₆ -alkylammonium chloride) 20 % Ethanol

Example C

10% methylene bisthiocyanate 4% thiabendazole 18% N-methylpyrrolidone 45% benzalkonium chloride (C ₁₂ -C ₁₆ ) 15% ethanol 4% 3-methoxypropionic acid 2% hypophosphorous acid 2% isononanoic acid

Example D

6.00% methylene bisthiocyanate 6.00% thiabendazole 41.25% benzalkonium chloride (C ₁₂ -C ₁₆ ) 13.75% ethanol 22.25% N-methylpyrrolidone 6.00% 3-methoxypropionic acid 2.75% hypophosphorous acid 2.00 % Isononanoic acid

Results

The following molds were isolated from the infested wood: Penicillum spp, Trichoderma spp, Aspergillus spp.

The blue and the mold growth was assessed on the surface. The blocks were checked after 6 months for the blueing Also split off the test time and also the bluing inside also assessed.

0 no infestation + punctiform growth on the surface Internal blue spots ++ In places vegetation, light inner blue +++ partly extensive vegetation, larger parts of the wood inside faded ++++ completely overgrown, fully faded inside

Claims (4)

1. Wood preservative based on methylenedirhodanide and 2- (4-thiazolyl) benzimidazole, characterized in that it contains a mixture of methylenedirhodanide, 2- (4-thiazolyl) benzimidazole, a quaternary ammonium compound and an acid which, when diluted with water gives an aqueous solution with a pH of 2 to 5. 2. Agent according to claim 1, characterized in that the agent 0.1 contains up to 20% (wt .-%) of methylenedirhodanide and when diluted with Water gives an aqueous solution with 0.01 to 2% methylenedirhodanide. 3. Process for protecting green wood against blue stain and mold, characterized in that the wood with an agent according to Claim 1 treated. 4. The method according to claim 3, characterized in that one used aqueous solution consisting of an agent according to claim 1 Diluted with water and which has a pH of 2 up to 5.