RU2380221C2 - Agent for wood protection against biological affect - Google Patents

Abstract

FIELD: technological processes, woodworking.

SUBSTANCE: invention is related to woodworking industry and is intended for protection of wood, for instance raw saw timber, against wood-staining and mould fungi. Agent is described for wood protection against biological affect on the basis of boric acid or its salts. Agent additionally contains the following components: as fungicides, triazoles are selected from tebuconazole and propiconazol, non-ionogenic surfactants or non-ionogenic surfactants mixed with cation-active surfactants, spirits and (or) ketones.

EFFECT: agent is highly efficient for protection of wood against biological affect and is relatively safe and convenient to use.

4 cl, 5 tbl

Description

The invention relates to forestry and woodworking industries and is intended to protect wood, for example raw lumber, from wood-staining and moldy fungi.

Known means for protecting wood from blueness and mold: according to A.S. USSR No. 1659194, IPC B27K 3/52, B.I. No. 24, 1991; by A.S. USSR No. 1698062, IPC B27K 3/34, B.I. No. 46, 1991 and according to the RF Patent No. 2045393, IPC ⁶ B27K 3/52, B.I. No. 28, 1995. However, these drugs are either characterized by low environmental and sanitary-hygienic indicators, or have poor protective ability.

Closest to the proposed one is a wood preservative (RF Patent No. 2147510, IPC ⁷ B27K 3/52, B.I. No. 11, 2000) with the following composition of components, wt.%: Boric acid or its salt 10-25 , sodium dimethyldithiocarbamate 10-30, sulfonates 20-30, carbonic salts or alkali metal bases, the rest is up to 100. The proposed tool may additionally contain quaternary ammonium salts (QAC) in an amount of 0.5-3 wt.% and is used in powder form or in liquid form.

It should be noted a number of significant disadvantages of this tool. Cooked in powder form, it is prone to dusting and therefore, due to the presence of toxic components in the formulation - boric acid, sodium dimethyldithiocarbamate and soda ash, it is a dangerous product for people working with it. In addition, the soda ash contained in the preparation (up to 50%) is hardly soluble in water. In significant quantities, it remains unused for its intended purpose; it is collected at the bottom of the bath for wood impregnation and thereby causes additional difficulties when cleaning these baths and disposing of the precipitate formed.

In the liquid form of this product, even during short-term storage (less than 1 month), due to high concentrations of caustic soda and boric acid, difficult to break and difficult to dissolve precipitates are formed, which leads to great difficulties at the stage of preparing working solutions for wood processing.

In addition, preparations supplied in liquid form create difficulties for consumers associated with the return of containers, their steaming before transportation or disposal.

In addition, this composition is not effective enough against the fungi Penicillium chrisogenum and Discula pinicola, which leads to the need to increase the concentration of working solutions and increased consumption of the drug to achieve the required levels of protection or leads to a decrease in the quality of timber in the presence of this type of fungus in the environment.

The sodium salt of dithiocarbamic acid used in the composition is unstable and undergoes hydrolysis with the formation of hydrogen sulfide, which affects not only the sanitary and hygienic characteristics, but also creates environmentally unfavorable conditions for use.

The proposed invention is aimed at increasing the biological efficiency and improving the operational properties of wood preservatives.

The problem is solved by a means to protect wood from damage by wood-coloring and mold fungi containing boric acid or its salts, triazoles (tebuconazole or propiconazole) and nonionic surfactants or nonionic surfactants mixed with cationic surfactants in the following proportions, wt.%:

boric acid 80-98.9 triazoles (tebuconazole or propiconazole) 0,1-10 Surfactant 1-10

Ensuring the necessary level of protection for wood and lumber is achieved through the combined use of boric acid (or its salts) and triazole (tebuconazole or propiconazole).

Surfactants are used not only to obtain a stable form of application of the composition, but also to reduce dust during operation. It is known that to reduce the dustiness of powdered antiseptic drugs, various additives are used, for example, mineral oils or other inert additives (Varfolomeev Yu.A. Ensuring the durability of wood products. - M .: Assol, 1992. - 288 s). As surfactants, nonionic ones (neonol, syntanol, OP-7, OP-10, etc.) and nonionic surfactants can be used together with cationic surfactants (for example, together with quaternary ammonium compounds).

Due to the presence of surfactants, boric acid does not dust, and thus the sanitary and hygienic properties of the drug are improved. Although boric acid is a substance of the third class of danger, in the process of application, getting it into the respiratory organs can lead to poisoning, and elimination of dusting is an important problem of powder preparations. We achieve this goal by using surfactants as part of the preparation.

The proposed tool for improving the impregnation of wood may additionally contain alcohols and ketones in an amount of 1-6 wt.%.

The proposed tool is a powder. The balanced composition of the product allows the use of working solutions for processing wood with relatively low concentrations of the active substance, while achieving a high degree of bioprotection.

Test formulations were prepared by pre-mixing the components. Tebuconazole (TBA), propiconazole (PKA) were used as fungicides. As alcohols, C ₂ -C ₈ primary or secondary alcohols or mixtures thereof were used (for example, fusel oils - heavy fractions of ethyl alcohol rectification). As ketones, acetone, methyl ethyl ketone (MEK) and methyl propyl ketone (IPC) are used. As a cationic surfactant - dimethylalkyl benzylammonium chloride (DMABAH) and triallylbenzylammonium chloride (TABAH). Appropriate impregnating solutions were prepared from the obtained compositions.

To test the proposed tool, samples were prepared with different content of components (table. 1).

Table 1 Sample No. The composition of the sample, wt.% Notes Boric acid triazole Cationic surfactant nonionic surfactant Alcohols or Ketones one 93.9 0.1 - 6 - Surfactant syntanol 2 94.9 0.1 - 5 - SAW-OP-7 3 98.9 0.1 - one - SAW-OP-10 four 98.9 0.1 - one - In samples No. 4-16 nonionic surfactant - neonol 5 95 one one 3 - with DMABAH 6 95 one one 3 - with TOBACCO 7 92 one 5 2 In samples No. 7-16 with DMABAH 8 89 one one 3 6 with ethanol 9 92 one one 3 3 with isamyl alcohol 10 80 10 one 3 6 with a mixture of alcohols C ₂ -C ₈ normal and isostructure eleven 89 one one 3 6 with IEC and ethanol, samples No. 11-13 with propiconazole 12 89 one one 3 6 with IPC and acetone (1: 1) 13 91 one one 3 four As in No. 9, but instead of boric acid - borax fourteen 80 10 one 3 6 As in No. 10, but with tebuconazole and propiconazole in a ratio of 1: 1 fifteen 87.95 0.05 3 5 four In samples No. 15-17 with a mixture of alcohols C ₂ -C ₈ normal and isostructure 16 82.9 0.1 8 3 6 17 70 eighteen 3 3 6

Samples 1-14 correspond to the claimed composition.

Samples 15-17 were taken with a prohibitive content of components.

For testing the claimed composition used samples of sapwood pine with a humidity of 80-120%, size 5 × 15 × 180 mm Samples were treated by immersion in impregnation solutions for 1 min. Impregnating solutions were prepared by dissolving the finished product in distilled water. Infection of the samples was carried out in desiccators with “sawdust buffer”. Sawdust from freshly sawn wood of sapwood of pine was irrigated with a suspension of mushrooms using a spray gun. The suspension contained 27 species of fungi, comprising 3 groups of 9 species each.

The first group includes the following types of fungi: Penicillium ochrochloron, Penicillium brevicompactum, Fusarium meniliforme, Alternaria humicola, Aspergillus niger, Aspergillus terreus, Penicillium chrisogenum, Phialophora fastigiata, Fusarium poae.

The second group includes the following types of fungi: Fusarium javanicum, Fusarium merismoides, Poecylomyces variotti, Sporidesmium cladosporioides, Trichosporium cheteromorphum, Aspergillus hennebergii, Discula pinicola, Cladosporium herbarum, Verticillium margudi.

The third group includes the following types of fungi: Aspergillus amstelodanum, Penicillium cyclopium, Alternaria tenuis, Fusarium culmorum, Penicillium purpurgenum, Aspergillus flsvus, Leptographium lundbergii, Trichosporium harzianum.

Evaluation of the effectiveness of the protective agent, as stipulated by GOST 30028.4-93, was carried out after 15 days of exposure, according to the average area affected by the fungi of the surface of the samples in percent and according to the stage of development of the fungus. The latter was evaluated on a six-point scale:

0 - absolutely pure samples during visual inspection and under a microscope;

1 - visually clean samples; when viewed under a microscope, small foci are visible in the form of spots of one type of wood-staining or mold fungi; sporulation stage is absent;

2 - surface development of mycelium of certain types of wood-staining and mold fungi in the form of spots; sporulation stage is absent;

3 - abundant growth of the mycelium of certain types of wood-staining or mold fungi; the beginning of the sporulation stage of one of the species of fungi

4 - fungal growth is clearly visible during visual inspection, various stages of sporulation of most species of wood-staining and mold fungi;

5 - deep damage by wood-dyeing and mold fungi of the entire area of the sample, intensive sporulation.

The test results are presented in table. 2.

table 2 Sample No. Absorption, g / m ² The degree of damage by fungi: area -%, stage of development - points Efficiency Note 1 groups 2 groups 3 groups % points % points % points one 0.41 <5 one <5 one <5 one highly effective 2 0.40 0 one 0 one 0 one highly effective - 3 0.40 0 one 0 0 0 one highly effective - four 0.39 0 0 0 0 0 0 highly effective - 5 0.38 0 0 0 0 0 0 highly effective - 6 0.40 0 0 0 0 0 one highly effective 7 0.41 0 0 0 0 0 one highly effective 8 0.51 0 0 0 0 0 0 highly effective 9 0.44 0 0 0 0 0 0 highly effective 10 0.49 0 0 0 0 0 one highly effective eleven 0.50 0 one 0 one 0 one highly effective 12 0.50 0 one 0 one 0 one highly effective 13 0.51 0 0 0 0 0 0 highly effective fourteen 0.50 0 0 0 0 0 0 highly effective fifteen 0.51 10 2 fifteen 2 10 2 Effective Active development of Penicillium mushrooms 16 0.53 fifteen one fifteen 2 fifteen one Effective 17 0.35 twenty fifteen twenty Effective Active development of Penicillium mushrooms 18 ^* 0.50 fifty four 40 four 35 four medium effective Active development of Penicillium mushrooms the control - 90 5 85 5 85 5 - *) Sample 18 corresponds to the composition of the prototype (RF Patent No. 2147510, IPC ⁷ B27K 3/52, B.I. No. 11, 2000).

The results obtained show a high effectiveness of the agent in the claimed ratio of components.

An increase in the surfactant content in the preparation above the stated leads to a deterioration in the flowability of the drug, and a decrease in the precipitation of triazole from the working solution.

The inclusion of alcohol, acetone, or a mixture thereof significantly improves the impregnation of wood with an antiseptic (samples 8-17), but an increase in their amount above the stated decreases the flowability of the drug.

The necessary level of wood protection can only be achieved with the combined use of boric acid (or its salts) and triazoles. As the results of mycological studies show, the use of only boric acid (Table 3) or the use of only tebuconazole does not provide the required level of protection (Table 4).

The recommended concentration in the production of chemical protection of lumber from biodefeat of the claimed composition is not more than 1-2%. The content of boric acid in the preparation is more than 80% and naturally in the aqueous solution its content will be from 0.8 to 1.96%. According to the results of mycological tests, at these concentrations boric acid does not provide the necessary level of wood protection (see table 3).

Table 3 * The results of laboratory mycological tests of an aqueous solution of boric acid Solution concentration Preservation of the surface of the samples (%), per day: 10 twenty thirty 40 fifty 1.0 65 22 21 fourteen 12 2.0 77 43 39 35 32 3.0 91 46 41 37 37 4.0 94 70 60 52 49 0.0 (control) 33 23 19 10 8 *) Galiakhmetov R.N., Varfolomeev Yu.A. Reducing the environmental hazard of antiseptics. - M .: Chemistry, 2004 .-- 187 p.

According to the same methodology (Chashchina L.M., Poromova T.M. Methods of testing protective agents against wood-staining and mold fungi // Drying and wood protection: Collection of scientific papers - Arkhangelsk: TsNIIMOD, 1985. - P.120- 127) the protective ability of tebuconazole against wood-dyeing and mold fungi was evaluated when used as a single drug. The test results are shown in table 4.

Table 4 The results of laboratory mycological tests of tebuconazole and its mixture with boric acid The con-tion of the drug in the working solution,% Preservation of the surface of the samples (%), per day: 10 twenty thirty 40 fifty TBK-0.001 95 87 83 76 72 TBK-0.01 96 90 86 80 76 TBK-0.1 98 90 87 82 77 TBK-1.0 98 92 90 81 76 H ₃ BO ₃ - 1,978% + TBA - 0,002% and 0.02% surfactant (as in example 3) one hundred one hundred one hundred 98 97 0.0 (control) 35 26 eighteen eleven 9

As can be seen from the table. 4, an increase in the concentration of tebuconazole (TBA) from 0.001 to 1.0% in a working solution without boric acid does not provide reliable protection of wood and does not lead to a significant change in efficiency. The combined use of boric acid and tebuconazole, together with other additives, provides reliable and more effective protection of wood from biodefeats.

Mycological tests of impregnated wood against wood-destroying fungi were also carried out using the “open ground” method (Kurbatova N.A. Improving the efficiency and environmental safety of protective wood treatment with fluoride-based preparations: Abstract of thesis. Candidate of Technical Sciences / ASTU. - Arkhangelsk , 1992. - 21 p.). In the experiment, we used conditioned sapwood pine samples of 20 × 20 × 5 mm in size, impregnated with the studied compounds according to the vacuum-atmospheric pressure method. The impregnated samples were weighed and placed in boxes with non-sterile forest soil. Infection was carried out by placing under the samples inoculant cubes with a culture of a wood-destroying fungus Serpula sclerotorum. The temperature and humidity during the tests were kept constant. Simultaneously with the impregnated samples, control non-impregnated samples were tested. After 16 weeks of testing, when the test samples were destroyed by 50-60%, the experiment was terminated, their macromycological description, conditioning and weighing were carried out. The condition of the samples was evaluated by weight loss (in% of the original). The results obtained are presented in table.5.

Table 5 The protective ability of samples No. 1-11 in relation to wood-destroying fungi Sample No. The concentration of the impregnating solution,% Mass loss% Macromycological characteristics of samples one 6.0 3.9 No decay and infection detected 2 6.0 2.1 No decay detected 3 6.0 6.7 No decay detected four 6.0 2,8 No decay detected 5 6.0 2.9 No decay detected 6 6.0 3,1 No decay detected 7 6.0 3.2 No decay detected 8 6.0 3.4 No decay detected 9 6.0 3.0 No decay detected 10 6.0 3,5 No decay detected eleven 6.0 3.8 No decay detected Control (untreated
samples) 0 54 Well-developed mycelium of wood-destroying fungus, deep light brown rot

Thus, the proposed tool for protecting wood due to its balanced composition and the absence of highly toxic compounds in it allows to increase biological efficiency and improve operational properties.

Claims (4)

1. An agent for protecting wood from biodefeat based on boric acid or its salts, characterized in that it further comprises triazoles selected from tebuconazole and propiconazole as fungicides, and nonionic surfactants or nonionic surfactants mixed with cationic surfactants in the following ratio of components, wt.%:
boric acid or its salts 80-98.9 indicated triazoles 0,1-10 specified surfactants 1-10 2. The wood preservative according to claim 1, characterized in that it further comprises alcohols and (or) ketones 1-6 wt.%. 3. The wood preservative according to claim 1, characterized in that it has a protective ability against wood-destroying fungi. 4. The wood preservative according to claim 1, characterized in that it is a bulk powder preparation.