DE1021158B - Process for the leach-resistant impregnation of wood, wood-based materials and textiles endangered by fungal and insect infestation - Google Patents

Description

Process for the leach-resistant impregnation of fungi and Endangered by insect infestation.

Wood, wood-based materials and textiles It has long been known that materials endangered by insects and fungi, such as wood, wood-based materials and textiles, with phenols and naphthols or their substitution products, in particular pentachlorophenol, can be impregnated. A disadvantage here, however, is the difficult introduction phenols and naphthols, which are normally insoluble or very sparingly soluble in water, in particular pentachlorophenol, in the material to be protected.

It is true that such impregnating agents can be used in oily media, e.g. B. Diesel oil or suitable petroleum fractions, and dissolve them in this form relatively easily in the materials to be impregnated, but this method of working due to the use of the relatively expensive oils, quite unprofitable as a solvent.

It also belongs to the state of the art, phenols and naphthols in the form of their water-soluble salts, namely the corresponding ammonium and alkali salts in combination with other compounds, e.g. B. sodium carbonate, sodium bicarbonate and borates.

In the case of using pentachlorophenolammonium it is also known, the free phenol by subsequent steaming of the treated material to fix. However, in this process it is due to the strong tendency to dissociate of pentachlorophenolammonium required to work with excess ammonia. Through this it becomes necessary to close the soaking process to avoid ammonia losses To make containers. This is the only way to premature precipitation of the pentachlorophenol and to avoid unpleasant odors. In addition, there is work in open containers not possible in practice because of the pungent smell of ammonia.

But it is now known that in particular from alkali pentachlorophenolate solutions the free pentachlorophenol cannot be easily fixed on the wood fiber. It is true that the action of air carbonic acid causes a chemical reaction in this sense C, C150Na + 11.0 -I- CO, = # t = C, C150H -I- NaHCO3, but this only runs up to a certain state of equilibrium, unless extreme dilutions are present. As a result, delay any action that increases the alkalinity of the system bring about the precipitation of the pentachlorophenol in a leach-resistant Form, such as the addition of borax or sodium carbonate.

Finally, it is known to use alkali salts of chlorinated phenols, in particular pentachlorophenol, which are known to be water-soluble and consequently can easily be incorporated into the material to be protected, in the treated To fix material, especially wood, in that a post-treatment of the with the phenolate-treated material with carbon dioxide and on in this way the chlorophenols are set free. It was also recommended that sodium pentachlorophenol be used to be combined with the alkaline sodium bisulphite that is used after impregnation by exposure to oxygen, lowering the pH value by three to four units to convert to sodium bisulfate, which will cause the free phenol to precipitate would. This is especially true for wood protection, namely for the impregnation of Bulk goods. But all this is due to the strong reducing effect of the wooden body only possible with restrictions, especially with heavily dimensioned wood, so that the risk of leaching of the impregnation salts still exists, in particular if there is a lot of moisture or when impregnating wet wood, before the desired reaction has even occurred.

It has now been found that water-insoluble phenols or poorly water-soluble phenols, in particular pentachlorophenol, in the form of their water-soluble salts, especially their water-soluble earth or alkali salts, can very easily be introduced into the material to be protected in leach-resistant form if one this is combined with water-soluble salts of halogenated carboxylic acids, preferably with alkali salts of monochloroacetic acid, in an aqueous medium and the resulting mixture of solutions reacts in the object to be protected by heating with elimination of hydrohalic acid salts. With sodium pentachlorophenol and sodium chloroacetate, this reaction proceeds according to the following scheme: However, it is not excluded here that a side reaction takes place to a certain extent which leads to the formation of phenoxycarboxylic acids, for example phenoxyacetic acid or their substitution products.

Suitable phenols are those substituted by negative groups Products, e.g. B. o- and p-nitrophenol, 2,4-dinitrophenol, 2,4-dichloro-6-nitrophenol, 2,6-dichloro-4-nitrophenol, o- and p-chlorophenol, 2,4,6-trichlorophenol, pentachlorophenol, 3-trifluoromethyl-4-nitrophenol, o-, m- and p-cresol and its technical mixtures and xylenols including halogenated and / or nitrated substitution products. In addition, condensation products, for example from aldehydes or ketones and phenols (cresols, xylenols), such as 4,4'-dioxydiphenylpropane be used. Suitable impregnation methods are: brushing and spraying, immersion impregnation and pressure impregnation.

Surprisingly, the mixtures result from these phenates with absolutely stable solutions to the water-soluble salts of halogenated carboxylic acids, so that they can be used repeatedly for impregnation processes, if necessary with the addition of wetting agents, can be used with the greatest success. Advantageously, those with these Solutions impregnated wood is heated briefly and immediately after impregnation attenuated to trigger the described reaction with the formation of insoluble phenols to bring or to accelerate.

The fact that the impregnation solution is stable is by no means self-evident from a chemical point of view, since the salts of strongly acidic phenols, e.g. B. pentachlorophenol or 2,4-dichloro-6-nitrophenol, normally already react clearly alkaline, so that in their presence, for example, sodium monochloroacetate, as is known to be very easily saponified to salts of glycolic acid -% , with the result of complete disintegration of the water-soluble phenates would have to be decomposed.

For the implementation of the procedure are suitable in place of the already named phenols (cresols, xylenols) as well as the OH substitution products of polynuclear Aromatics which, due to their weaker acidity, have a tendency towards hydrolysis Form earth or alkali salts. The following are listed: a- and f-naphthol, 1-, 2- or. 9-oxyanthracene or 2,2'-dioxydiphenyl, which of course also in turn May contain heteroatoms or functional groups such as Cl and N 02. They are advantageously in mixtures with the water-soluble salts of halogenated carboxylic acids selected for those wood preservation processes that require long-term storage the soaking salt solution is not required, for example when spraying, brushing or Short immersion process, since the conversion and formation of free phenols or naphthols is already happening takes place briefly and at normal temperatures.

Among the representatives of the halogenated carboxylic acids are suitable all those which are able to saponify or to saponify in the presence of alkali condense or polycondense, such as earth or alkali salts of the mono- or Dichloroacetic acid or a technical mixture of both or mono- or poly-halocarboxylic acids, those in the a-position at least one halogen, in particular chlorine atom and optionally contain other heteroatoms, such as a-chlorobutyric acid, a, cu-dichlorobutyric acid or technical mixtures thereof. These are used to produce the actual Impregnation salts or solutions, expediently in equimolecular proportions, under certain circumstances but also in a different ratio, either immediately before the application or given in more or less long time interval beforehand and in the form of their aqueous solution on or in the material to be treated, e.g. B. dry (: masts, Construction timber, etc.) or fresh wood, wood-based materials (fiber, chipboard insulation boards) and optionally textiles such as tarpaulins, tent cloth and the like. In addition one uses one of the technically generally customary impregnation processes, e.g. B. the Boiler pressure impregnation.

Some examples of the process according to the invention are given below for explanation: Example 1 Finished beams, masts or railway sleepers are impregnated in a pressure vessel according to the full impregnation process under vacuum and pressure with a 1 to 2% aqueous solution of a salt mixture, which consists of 700i , Pentachlorophenol sodium and 300 /, sodium monochloroacetate and a suitable, water-soluble wetting agent. After the impregnation solution has been drained from the boiler, the wood is subjected to brief heating to 70 to 130 °, depending on its dimensions. The freshly soaked wood contains pentachlorophenol, which is difficult to leach, and can be processed or installed immediately after drying.

Example 2 For the treatment of standing wooden structures (barracks, barns, Sheds and the like), also for fresh sawn timber in sawmills and on the room places (here especially against blue stain pathogens), there is a 5% aqueous solution Solution of a salt mixture use, which consists of 58 ° j, ß-naphthol sodium and 42 0, i ', Na monochloroacetate and a suitable, water-soluble wetting agent. The solution prepared as required is applied by brush or spray Use of around 10 to 30 g / m2 applied to the wood in one to three work steps. Immediately after the treatment, the hard-to-leach and strong arises in the wood F-naphthol with a fungicidal and insecticidal effect, which also penetrates when re-moistened Precipitation ensures lasting protection.

Claims (3)

PATENT CLAIMS: 1. Process for leach-resistant impregnation of materials endangered by fungal and insect infestation, especially wood, wood-based materials and textiles, normally insoluble in water or sparingly soluble in water Phenols or naphthols, in particular pentachlorophenol or f-naphthol, thereby characterized in that the objects to be protected with aqueous solutions of Salt of the phenols or naphthols mentioned and salts of halogenated carboxylic acids, preferably Alkali salts of monochloroacetic acid, impregnated in a known manner and in the material treated in this way, the free phenols or naphthols by heating fails. 2. The method according to claim 1, characterized in that the precipitation of the phenols or naphthols by brief heating, expediently to 70 up to 130 °, of the impregnated materials in the pressure vessel. 3. Procedure according to Claim 1 or 2, characterized in that impregnating solutions containing wetting agents is being worked on. Considered publications German patent specifications No. 837 924, 915 623; U.S. Patent Nos. 2,186,134, 2,322,633.