SE520908C2 - Wood Preservation method - Google Patents

Abstract

The invention relates to a process and a means for protecting wood material against decomposition and similar undesirable reactions provoked by micro- organisms. According to the process, the wood material is treated with a wood protection agent which combats the growth and spread of micro-organisms. According to the invention, a preparation is used containing crude tall oil. Preferably, a composition of crude tall oil is used, in which the weight relationship between the fatty acids and the resin acids is greater than 1 and which contains ca. 45-70% fatty acids and ca. 40-10% resin acids, the remainder of the composition consisting of neutral substances. The wood protection agent consists, for example, of a composition of crude tall oil which has been made from a softwood-soap mixture and diluted with a suitable solvent, such as white spirit, pinene turpentine or xylene, and to which drying agent has possibly been added.

Description

25) 520 908 2) Oil-based impregnating agents contain one or more active substances in an organic solvent, usually white spirit. The active components consist of organic compounds: tributyltin taphthenate (TBTN), tributyltin oxide (TBTO), mixtures of penta- and tetrachlorophenols, diclafluanide and iodopropynylbutyl carbamate. 3) Creosote oil is a component of coal tar obtained by distillation at a temperature above 200 ° C. More than 300 different compounds have been found in creosote oil, most of which, however, occur in very small concentrations. The action of creosote oil on organisms is based on a combination of these components.

The current wood preservatives have significant disadvantages. Thus, they contain toxic substances, which means that the permits of the relevant authorities are first obtained before they can be used. The toxic effect of impregnating agents is based on so-called general toxicity and is directed primarily at the vital metabolic processes that are common to all living organisms, such as cell landing and the production of the high-energy compound ATP. As these are general toxins, the use of conventional wood preservatives is associated with significant health (eg carcinogens) and environmental risks (soil and water pollution). The health risks affect all eukaryotic organisms, such as plants, animals and humans. If, on the other hand, the amounts of copper, arsenic and chromium in e.g. CCA impregnating agents make it difficult to get the impregnating agent to adhere to the wood, and the efficiency of the impregnating agent also decreases noticeably when the heavy metal contents decrease.

The object of the present invention is to overcome the disadvantages associated with the prior art, and to provide a completely new method for protecting wood against rot and other similar undesirable reactions caused by micro-organisms. organisms and which weaken the strength properties of wood or otherwise reduce its economic value.

The invention is based on the idea that the wood is treated with a composition which contains fatty acids, resin acids and any neutral substances which are native to the wood. Preferably, such a composition is used crude pine oil, which can be prepared from the leachate of an alkaline wood preservative diluted composition of crude pine oil, in which a substance, such as sulphate cooking, may have been added separately. Preferably, according to the invention, this comprises comprising promoting the polymerization of the oils in the composition with a suitable solvent.

More specifically, the use according to the invention is characterized by what is stated in the characterizing part of claim 1.

In the context of this invention, the term "undesirable reactions caused (or caused) by microorganisms" is used to denote the damage and destruction of wood caused by fungi and mold. Wood is worst damaged by the above-mentioned rot fungi, such as brown rot fungi and white rot fungi, but also blue-surface fungi and mold cause economically significant damage to wood.

Examples of brown rot fungi are the following: house fungus (Serpula lacrymans), cellar fungus (Coniophora puteana), pore fungus (Poria p / acenta) and sauna fungus (G / ocophy // um trabeum). These break down the wood constituents, cellulose and hemicellulose, by means of hydrolytic and oxidative reactions, which lead to radical reactions. The destruction of the wood is usually characterized by its weight loss.

Lead and mold fungi damage wood as they cause color defects.

Among the fungi that cause manure damage, it is worth mentioning in particular the species that belong to one of the genera C / adosporium, A / ternaria, Helminthosporium. Penicillium, Aspergillus, Epicoccus and Rhizopus. Of these micro-organisms, it is in particular the molds belonging to the genera Penici // ium and Aspergia / lice that cause major damage to wooden structures and to the interiors of buildings. Blue-surface fungi that occur in wood, on the other hand, preferably belong to the genera Ambrosie // a, Aureobasidium, Ceratoeystis, C / adosporium and Ph / a / ophora. The most common blue-surface fungi that cause bluishing of pine wood include those belonging to the genera, Aureobasidium pu // u / ans and Ceratocystis, as an example Cilpilifera can be cited. Mixing of spruce sawdust is caused not only by the above-mentioned fungi but also, among other things. of the strains Ceratocystis piceae and C. coeru / escens. Strains belonging to the genus Sc / erophoma also occur in softwood sawdust, for example Sc / erophoma entoxy / ina.

The invention can be applied to protect wood against all undesirable reactions caused by the above-mentioned microorganisms. The invention is preferably used for the protection of felled wood, such as sawn timber (eg planks, rafters and beams) and posts, but can also be applied to veneers and fibers. Within the scope of this invention, the term "crude tall oil" generally refers to a composition which contains a mixture of fatty and resin acids from wood. In crude tall oil, the proportion of fatty acids and resin acids is at least approximately the same as in wood. In addition to these components, crude pine oil usually also contains so-called neutral substances, or non-acidic compounds.

Resin acids distilled from tall oil and their salts have been used in some known wood preservatives as additives for viscosity control and to prevent solubility of the agents. In this connection, reference is made to CA patent specification 1,058,353. According to the present invention, however, fatty and resin acids are not separated from the tall oil, but are used as such, i.e. as crude tall oil, whereby the desired properties are achieved without additional costs for the separation. Crude tall oil is typically prepared from mixed soap dispersed in aqueous acetone solution and obtained in an alkaline sulphate boiling by first removing most of its neutral substances by liquid-liquid extraction and then acidifying the acetone phase, whereby fatty and the resin acids are converted to acid form. As the extractant in the liquid-liquid extraction, for example, non-polar hydrocarbons such as hexane are used. The crude tall oil obtained is separated by decantation. As a starting material in the production of crude pine oil, the liquor of coniferous and birch wood chips (black liquor) is preferably used, but liquids of pure coniferous coke (eg a pine / spruce sulphate boil) are also suitable as a base for the production.

The proportion of finic acids and resin acids varies depending on the type of wood in the boil; crude pine oil from pure pine wood typically contains about 18 - 60% fatty acids resp. about 28 - 65% resin acids. The amount of neutral substance here amounts to about 5 - 24%. According to the invention, it has been found to be advantageous to use crude tall oil which contains more finic acids than resin acids. The greater the proportion of fatty acids, the lower the viscosity of the crude tall oil, which in turn facilitates the treatment of the wood. On the other hand, many substances, which prevent the growth and spread of microorganisms, are made up of resin acids, so the content of these must not be too low either. In general, according to the invention, it has been found to be advantageous to use crude tall oil, which has a weight ratio of fatty acids to the resin acids of about 10: 1 - 1: 1. resin acids, the rest of the composition consisting of neutral substances. The acid number for such a crude tall oil is typically around 150 - 155, while the corresponding figure for ordinary crude tall oil amounts to a maximum of 140.

These crude pine oils advantageous according to the invention are obtained, for example, from birch-pine and birch-pine-spruce soap mixtures. Since there is not exactly any resin acids in birch wood, soap separated from the black liquor of a birch coke or combined liquors of birch / coniferous coke has a higher fatty acid / resin acid ratio than soap obtained in a coniferous coke. 10 15 20 25 30 520 908 6 The composition and properties of a particularly advantageous crude pine oil (birch / pine / spruce) are given below: Table 1. Composition and properties of crude pine oil composition properties about 60% fatty acids 20-25% resin acids about 10% neutral substances 1-2% H 2 O (as impurities Na 2 SO 4 and CaSO 4) acid number 150-155 saponification number 160-165 unsaponifiable% 10-11 pH 5.3 ash% 0.002 When in connection with this invention reference is made to the "oils" in crude tall oil, refers to the above-mentioned fatty acids and resin acids and corresponding glycerides.

The fatty acids in crude tall oil consist of oleic acid derivatives and the resin acids of abietic acid derivatives. Of the fatty acids, the olein, linoleic, palmitic, stearic and linolenic acids may be mentioned, and of the resin acids abietic, neoabietic, pimaric, isopimaric, palustrine and dehydroabietic acids. Many of these oily compounds polymerize by themselves. According to the invention, it has been found that the polymerization of the oils in wood can be promoted by adding to the composition of crude tall oil substances which favor the polymerization of the oils (siccatives), such as metals, for example metals or cobalt (or combinations thereof) or organic compounds, for example pinenterpentin. whereby the seepage of crude pine oil out of the treated wood can be substantially reduced or even completely prevented. The amount of metal used as a siccative varies depending on the metal, but in the case of Co and Mn it typically amounts to 0.001 - 0.5% (eg 0.005% -0.2%) by weight of the composition of the preservative. Other metals are added as needed, even in larger quantities.

Manganese and cobalt are known leachates, and their use in paints and varnishes is discussed, for example, in the work Technology of Paints, Varnishes and Lacquers, CR Martens (ed), Robert E. Krieger Publishing Company, Florida, 1974. In connection with the present invention, it has been found that pinenterpentine acts as a sedative. Its polymerizing action is slower than that of the above-mentioned metals, which is advantageous in such applications, where one strives to have the wood preservative absorbed as deep into the wood as possible. Combinations of metals and turpentine can also be used to advantage as a desiccant.

Crude pine oil is suitable either as such or diluted with white spirit, pinenterpentin, xylene or equivalent non-polar solvent or solution mixture for impregnation or surface treatment of wood. All compounds that are included in crude pine oil are used, many of which have been found to grow fungi as an example. diterpene compounds are listed: palustric acid, dehydroabietic acid and isopimaric acid. The sitosterol residues in the neutral part also constitute fungal inhibitory compounds. From birch timber, for example, prenols and squalene are transferred to the crude pine oil, the effect of which on fungi is not yet known. Crude tall oil probably contains small amounts of several different compounds, bi. a. pinosylvin, which together are important for wood protection.

Per part by volume of the crude tall oil, 0 to about 70 parts by volume of solvent are usually added to prepare a solution, dispersion or emulsion.

Preferably, the proportion of crude pine oil in the mixture of crude pine oil and solvent is about 5 - 90%, it is especially advantageous then that the proportion is at about 30-60%. 10 15 20 25 30 520 908 8 l of crude tall oil, or in the solution, dispersion or emulsion prepared therefrom, other per se known excipients may be included, which favor the penetration of the solution into the wood material. In addition to biologically inert excipients, the wood preservative according to the invention may also contain known, biologically active compounds, which prevent the growth of fungi and mold. These include, for example, copper ions, copper complexes and boron ions. The latter also act as insecticides and as fire protection agents.

The product based on crude used which is tall oil can be impregnating agent or surface coating agent. As impregnating agents SOm can be used crude pine oil as such, crude pine oil diluted with solvent, crude pine oil together with leachate, crude pine oil diluted with solvent and together with leachate, and crude pine oil together with other substances known for their ability to prevent fungal growth and mold and with or without sickness. For industrial impregnation in one or two phases, a composition is suitable, for example, in which copper and / or boron as well as any leaks are added to crude oil, which may be diluted with solvent. Boron is particularly suitable for impregnation in two phases.

In surface coating, the surface of the wood to be treated, such as sawdust, is treated with a crude tall oil product in a manner known per se, for example with a brush or spray gun. The raw pine oil gives the wooden surface a brown color tone, which makes it easy to see which areas have already been treated.

When impregnating, the aim is to get the impregnating agent to penetrate below the surface of the wood. This treatment can be carried out, for example, by pressure impregnation, whereby crude tall oil which is diluted with solvent and whose concentration is, for example, about 20 - 80%, is brought into contact with wood under an overpressure of about 1 - 16 bar, preferably about 1 - 15 bar.

The pressure treatment can be combined with a previous and / or subsequent vacuum phase, whereby air and moisture resp. solvent is removed from the wood. The impregnation is usually carried out at factory temperature, but in order to promote the polymerization of the oils in the crude tall oil, the wood can, if desired, be subjected to heat treatment after the impregnation.

Characteristic of softwood timber, which is protected with a composition of crude pine oil, is that the ratio of fatty and resin acids in at least part of its wood material is greater than in native wood. Likewise, the acid number in this part is greater than native, typically above 140 (also 150 - 155).

Significant benefits are associated with the use of crude pine oil in wood protection. Crude pine oil is obtained from wood as a by-product of the sulphate cellulose industry. It is an already existing product that is produced in larger quantities than what is further processed, and using it as such to protect wood does not increase the environmental impact. Nor does the use of crude pine oil in the protection of wood require any further refining of the preparation.

In addition, it is worth pointing out that crude pine oil results in a browning of the wood without pigment or dye additives. The color thus obtained is capable and sufficient for a number of products.

In the following, the invention is described in detail with the aid of a number of exemplary embodiments.

Example 1 Degradation test Rot fungi: Basement fungus (Coniophora puteana) and a fungus belonging to the pore fungi (Por / 'a p / acenta) were determined.

The starting dry weights of pieces of sapwood of pine The specimens were vacuum impregnated with crude pine oil, the temperature of which was 60 ° C, or with room temperature xylene solution of crude pine oil, with a crude pine oil content of 34%. The uptake of the impregnating agent was determined by weighing. The pieces were allowed to dry at room temperature for four weeks. In accordance with the European standard EN 84, all specimens were rinsed with water for two weeks. After two weeks of drying, all specimens were sterilized by irradiation (Co-60). The sterilized specimens were placed in beaker bowls on top of a fungal culture on a mallasagara substrate. In each bowl was placed an impregnated specimen and an unimpregnated reference piece.

The test was also performed with xylene impregnated and with impregnated pieces.

The degradation test was carried out in accordance with European standard EN 113.

When the decomposition time expired, the specimens were dried at 103 ° C, and the weight losses of the pieces were calculated according to EN 113. Calculatory weight losses of pieces impregnated with crude tall oil were significantly greater than the visible decomposition of the pieces, so the compressive strength was also determined for the pieces. .

The results show (Table 1) that in the decomposition test the compressive strength of pieces of sapwood of pine impregnated with solutions of crude pine oil remained greater than the compressive strength of xylene impregnated or unimpregnated reference pieces. When the compressive strength is considered as a function of the weight loss, the weight loss of specimens impregnated with tall oil can be estimated to be around 5%.

Table 1. weight losses (%) and compressive strengths (N / mmz) obtained in a degradation test according to EN 113, and the standard deviations / these of these in parentheses.

Treatment Qoniophora puteana- Porta p / acenta Ster. control% N / mmz% N / mmz N / mmz 10 15 20 25 30 35 5 2 0 9 0 8 11 100% tall oil 60 ° C 11.7 "58.1 (7.2) 26.9" 63.1 (4 , 8) 68.2 (8.0) Control 33.9 - 18.7 - 34% tall oil 16.5 "58.1 (7.2) 11.9" 62.9 (4.7) 73.7 (2.0) Control 35.0 - 17.5 - Xylene 21.9 26.4 (5.8) 21.7 19.6 (7.7) 75.3 (2.2) Control 34.4 25 .9 Virulence- 29.4 18.0 (4.5) 17.4 30.9 (5.9) 79.1 (4.1) control - - "Weight losses do not correspond to degradation Example 2 Degradation test according to standard proposal prENV 807 Rotten fungi : soft root fungi: Chaetomium g / obosum, Phia / ophora mutabi / is, Humico / a gr / sea, G / enospora graphii, Trichurus spira / is och Pterie // a setifera.

The starting dry weights of pieces (40x15x5 mm) of pine sapwood were determined. The specimens were vacuum impregnated with xylene solutions of crude pine oil, with a crude pine oil content of 66.7%, 50% and 33.3%, respectively. The uptake of impregnants was determined by weighing. The pieces were allowed to dry at room temperature for 4 weeks, after which they were rinsed according to European standard EN 84 (see example 1). The pieces were allowed to dry until they showed a moisture content of 50%. Three parallel specimens sterilized by irradiation were placed in a glass jar containing moist vermiculite.

The culture medium was inoculated with a mixed spore suspension made from soft root fungi. The test was also performed with three test pieces impregnated with creosote oil, and xylene solution of xylene copper-chromium-salt solutions (4 degrees Celsius) and with unimpregnated reference pieces. 10 15 20 25 30 35 520 908 12 The degradation sample was employed in accordance with the proposal for the European standard prENV 807. The degradation time was the culture room was low at 27 ° C, while the humidity was 70% RH. After 16 weeks and the temperature at the end of the decomposition time, the specimens were dried at 103 ° C and their weight losses were calculated.

The results (Table 2) show that crude tall oil reduced the weight losses caused by soft root fungi. The calculated weight losses were probably too large, as the degradation was not as clear as the weight losses suggest.

Table 2. weight losses obtained in a 16-week soft root deposition / surface test on vermiculite substrate performed according to prEN V 807.

Treatment kg (active substance) / m3 Weight loss Tall oil 66.7% 356 4.6 Tall oil 50% 275 13.4 Tall oil 33.3% 180 9.8 Creosote oil 12.5% 70 1.2 Creosote oil 27% 146 0.9 Creosote oil 40% 225 0.7 CC-ref. 0.40% 1.8 0.7 CC-ref. 0.63% 3.1 0.8 CC-ref. 1.0% 4.8 1.0 CC-ref. 2.5% 12.2 0.1 Xylene - 15.2 Untreated - 16.4 Example 3 Degradation carried out in unsterilized soil according to prENV 807 Degradation test in unsterilized soil, with mainly soft root fungi in the soil as rot fungi. 10 15 20 25 30 520 908 13 The starting dry weights of pieces (100x10x5 mm) of sapwood of pine were determined. The specimens were impregnated with xylene solutions of crude pine oil, pine oil of 66.7%, 50% or 33.3%.

The uptake of impregnating agents was determined by weighing. The pieces with a content of crude were allowed to dry at room temperature for 4 weeks, after which they were rinsed according to European standard EN 84 (see example 1). Then the pieces were allowed to dry until they showed a moisture content of 50%. The above specimens were placed in an upright position in moist soil in a box and they were allowed to decompose for 8, 16, 24 and 32 weeks in a culture room where the temperature was at 27 ° C and the moisture content at 70% RH. The procedure corresponds to the proposed European standard. The test was also performed with three test pieces impregnated with xylene solution of creosote oil, xylene and with 1.3% copper-chromium salt impregnated reference pieces.

After the end of the decomposition times, the specimens were dried at a temperature of 103 ° C and the weight losses were determined. Since the weight losses of pieces impregnated with crude pine oil and creosote oil did not appear to correspond to their degradation, the flexural strength of the pieces was also determined. By comparing the flexural strength values with the flexural strength values for the corresponding impregnated reference pieces and with the weight losses of the pieces, it could be concluded that the largest weight losses of the pieces impregnated with crude pine oil were below 7%, and at 8% of the pieces impregnated with creosote oil. Impregnation with crude pine oil reduced the degradation of the pieces. The results are presented in Tables 3 and 4.

Table 3. Weight losses (%) of the specimens obtained from tests in the mu // veed performed according to prEN V 807.

Treatment Uptake "Weight loss% kg / ma 8 v 16 v 24 v 32 v Ta || 0 | yes 66.7 ° / o 356 10.9 14.0 17.8 18.9 5 2 0 Tall oil 50% 267 TaHoIja 33 , 3% 174 Creosote oil 40% 224 Creosote oil 27% 149 5 Creosote oil 12.5% 70 Xylene (solvent) 5529 CC ref. 1.3% 10 Untreated - 908 14 9.5 6.2 5.7 4.2 2 .0 3.9 0.1 3.1 9.1 12.8 5.0 8.3 5.3 9.3 0.8 8.1 19.6 16.8 6.6 9.9 7.2 14.3 1.4 12.3 21.7 21.9 8.6 12.4 10.5 17.0 0.5 15.9 10 1) uptake of active substance 2) uptake of solvent 10 15 20 25 30 520 908 Table 4. The flexural strengths (N / mmz) of the test pieces obtained in tests in accordance with prENV 807, and their dispersion.

Treatment Uptake "Bending strength (N / mmz) kg / ma 8 v 16 v 24 v 32 v Taumja 66.7% 356 50.0 51.1 49.2 44.4 (1o, o) (5.9) (11 , 1) (8.4) Tanol 50% 267 56.3 44.5 46.1 46.6 (6.5) (3.3) (5.5) (6.0) Tanoua 33.3% 174 49.1 44.7 47.4 38.5 (9.0) (11.9) (7.7) (8.3) Creosote oil 40% 224 61.9 48.0 40.7 42.8 (6 , 1) (1.7) (4.7) (6.9) Creosote 27% 149 53.8 47.6 46.4 36.1 (8.1) (3.8) (7.3) ( 8.9) Creosor oil 12.5% 7o 61.7 49.6 47.2 45.3 (6.1) (6.3) (6.6) (6.5) xylene (solvent) 5520 42.3 36.3 35.6 23.3 (6.7) (6.8) (7.9) (6.4) cc-ref. 1.3% 10 61.4 59.4 65.4 64.5 (7.6) (3.1) (8.1) (8.8) untreated - 49.5 36.5 34.9 29.6 (1o, 3) (9.8) (7.2) ( 3.4) 1) uptake of active substance 2) uptake of solvent 10 15 20 25 520 908 16 Example 4 Degradation test - interaction of crude tall oil and boron The effect of the combination crude tall oil / boron was tested with a degradation test, where the basement fungus (Coniophora puteana) acted as a rot fungus.

The specimens were vacuum impregnated with 0.3, 1 and 5% solutions (Timbor °). impregnating agent was determined by weighing. The pieces were first allowed to dry. Half of each treated group was then impregnated with 40% xylene solution of crude pine oil, with which a series of clean specimens were also impregnated.

The uptake of impregnating agents was determined. The specimens were allowed to dry at room temperature for 4 weeks. Half of each group of specimens were rinsed according to standard EN 84. After two weeks of drying, they were sterilized by irradiation (Co-GO). The reference samples used xylene and virulence control.

The decomposition test was carried out in accordance with standard EN 113. After the end of the decomposition time, the test pieces were dried at a temperature of 103 ° C, and the weight losses of the pieces were calculated. The calculated weight losses of pieces impregnated with crude pine oil were greater than visible degradation, so that the compressive strength was also determined for the pieces. The results showed that specimens impregnated with crude pine oil and boron and rinsed showed greater strength than specimens impregnated only with boron impregnating agents. Crude pine oil reduced the rinsing off of boron.

Claims (12)

10 15 20 25 30 520 908 17 PATENT REQUIREMENTS The use of a preparation containing crude pine oil as such or a composition of crude pine oil diluted with a suitable solvent, for microorganisms against unwanted reactions caused by the protection of wood material. Use according to claim 1, characterized in that a composition of crude tall oil is used, which has a weight ratio between fatty and resin acids, which is at about 10: 1 - 1: 1. Use according to claim 2, characterized in that a composition is used which contains about 45 - 70% fatty acids and about 40 - 10% resin acids, the rest of the composition consisting of neutral substances. Use according to claim 1, characterized in that a composition of crude pine oil diluted with white spirit, pinenterpentine or xylene is used as wood preservative. Use according to claim 1, characterized in that a crude tall oil composition is used as wood preservative, which contains a substance which counteracts the growth of fungi and / or mold. Use according to claim 5, characterized in that the composition contains copper or boron. Use according to any one of the preceding claims, characterized in that a composition of crude tall oil containing a substance which promotes the polymerization of oils is used as wood preservative. 10 15 520 908 18 Use according to claim 7, characterized in that pinenterpentine and / or manganese or cobalt ions are used as the substance which promotes the polymerization of oils. Use according to claim 1, characterized in that the content of crude tall oil is around 5 - 90%, preferably around 30 - 60%. Use according to claim 1, characterized in that the acid number of the crude tall oil composition is higher than 140. Use according to claim 1, characterized in that the preparation is obtained from the black liquor of sulphate boiling, in which hardwood chips resp. softwood defibrated. Use according to claim 11, characterized in that the preparation is prepared from a birch-talc, birch-spruce or birch-pine-spruce soap mixture.