CS228918B2 - Salt-based preservative for wood protection - Google Patents

Abstract

A saline wood preservative containing inorganic compounds of fluorine, boron, potassium, sodium and phosphorus is characterized by that in order to eliminate the evolution of gaseous hydrogen fluoride a composition is applied which consists of 35-65 parts by weight of potassium bifluoride, 1-45 parts by weight of sodium chloride, 1-25 parts by weight of sodium tetraborate, 5-25 parts by weight of dibasic potassium phosphate and 0-1.0 part by weight of surface-active agents from the group of esters.

Description

The invention relates to a water-soluble salt-based preservative for the protection of wood in which it is toxic. the other are fluorine, boron, potassium, sodium and phosphorus compounds.

The use of the aforementioned inorganic compounds, in particular fluorine compounds and boron compounds, for the production of wood preservatives is known. The best known fluorine compounds used for wood protection are sodium fluoride, potassium fluoride, zinc fluorosilicate, potassium hydrofluoride, ammonium hydrofluoride and ammonium fluoroborate. The fluorine compounds are used individually for wood preservation, (sodium fluoride), usually as a component of the wood preservatives produced.

Known wood preservatives, Wolman's salts, in addition to fluorine compounds, include chromium compounds (U salts), chromium compounds and arsenic (UA salts, UII salts). Hydrofluoride-based compositions are also produced.

The use of boron compounds for wood preservation is similar to that of fluorine compounds. Wood preservatives, such as Boliden salts, Wolmanite CB disclosed in GDR 54,100, Synpregnit CBZ, Soltox R-12, contain a boron compound in its composition. Wood preservatives, containing fluorides or hydrofluorides and chromium compounds, when impregnated with wood, have the ability to fix themselves in wood due to the formation of water-insoluble compounds. Preservatives containing boron compounds in addition to the above compounds have similar properties. The formation of poorly water-soluble compounds in treated wood with the participation of chromium and fluorine or chromium and boron immediately after impregnation prevents further penetration of chromium further into the wood by the presence of fluorine and boron, even in wood with a high moisture content. The depth of penetration of these compositions into the air-dried wood varies between 2 and 4 mm during the pressureless impregnation process and between 4 and 6 mm in wood with higher humidity.

Hydrofluoride-based preservatives (e.g. Improsol) penetrate into the wood considerably deeper and have the ability to penetrate deeper into the wood after the impregnation process. However, such impregnated wood releases large amounts of gaseous hydrogen fluoride (H2F2) during drying in air, which has very damaging effects on the environment. Therefore, after impregnation with such a preservative, the wood must be allowed to air dry for approximately 12 weeks before it can be used for construction purposes. The main drawbacks of preservatives containing chromium and fluorine or chromium and boron are: penetration to a low depth, poor penetration into wood after supersaturation and permanent discoloration of wood.

The above-mentioned drawbacks are overcome by the wood preservative salt preservative according to the invention, which consists of 5 components composed of inorganic compounds; they are potassium hydrofluoride, potassium hydrogen phosphate, sodium tetraborate or orthoboric acid, sodium or potassium chloride, and a surfactant. Until now, these compounds have not been used in this combination as components of a wood preservative.

Each component of this complex cannot fulfill the intent to the extent that a mixture of these components. A mixture of these components was selected to achieve high fungicidal and insecticidal value, deep wood penetration and good water solubility. Due to the application of these compounds in the mixture to the wood surface, there is no salt salting out and reaction of the reagent. . Yippee . neutral. The resulting mixture has low sensitivity for eluting with water from wood. The use of boric acid in the complex in addition to potassium hydrofluoride leads to the formation of a solid fluoroborate ions complex. Fluorine is bound in this complex and the absence of gaseous hydrogen fluoride from wood is a characteristic of this wood preservative containing fluorine compounds.

The addition of a surfactant from the group of esters to the preservative according to the invention makes it possible to increase the depth of penetration of the composition into the wood.

A wood-based salt preservative containing inorganic fluorine, boron, potassium, sodium and phosphorus compounds is characterized in that it is a mixture of 35 to 65 parts by weight of potassium hydrofluoride, 1 to 45 parts by weight of sodium chloride or potassium chloride, 25 parts by weight of sodium tetraborate or orthoboric acid, 5 to 25 parts by weight of potassium hydrogen phosphate and 0 to 1.0 parts by weight of an ester surfactant.

The preservative according to the invention is used in the form of an aqueous solution having a concentration of 5 to 15. %.

The wood-based salt preservative according to the invention has the ability to penetrate deeply into the wood (both air dried and wet wood) and does not change the natural color of the wood. Yippee. very soluble in water and odorless. The preservative according to the invention also has the ability to penetrate deeply into the wood by diffusion, when the impregnated wood is stored under conditions in which the moisture content of the wood does not change, the penetration depth of the preservative in the air-dried wood increases by approximately 100%. , in wood with higher humidity by more than 100%. In non-pressurized impregnation methods and diffusion processes, the use of the composition according to the invention allows penetration to a depth of more than 20 mm. The preservative according to the invention effectively protects wood and lignocellulosic materials against the degradation action of microorganisms, and is characterized by a strong toxic effect against insects, technological wood pests. By selecting the appropriate chemical preservative compounds and precisely selected amounts of each of the components of the composition on the basis of the experiments, a wood preservative has been created which. it contains hydrofluorides and has no harmful effects on the environment. Removal of the basic drawback of this group of preservatives, namely the release of hydrogen fluoride gas, is another essential advantage of the preservative of the invention.

The preservative according to the invention is illustrated in more detail in the examples below.

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A 10% aqueous solution of the following components is used for impregnation of air-dried wood:

- 39 parts by weight of potassium hydrofluoride, - 45 parts by weight of potassium chloride, - 4 parts by weight of sodium tetraborate, - 11 parts by weight of potassium hydrogen phosphate, - 1 part by weight of ethylsulphuric acid.

Example 2

A 15% aqueous solution of the following components is used for impregnation of wet wood:

- 32 parts by weight of potassium hydrofluoride, - 38 parts by weight of sodium chloride, - 6 parts by weight of acid. orthoboric, - 23 parts by weight of potassium hydrogen phosphate, - 1 part by weight of ethyl acetate.

Example 3

For impregnation of air-dried wood, a 5% aqueous solution of the following components is used:

- 35 parts by weight of potassium fluoride,

- 25 parts by weight of sodium tetraborate, - 25 parts by weight of potassium hydrogen phosphate, - 15 parts by weight of potassium chloride.

Example 4-45 parts by weight of potassium hydrofluoride, 40 parts by weight of sodium chloride, 9 parts by weight of orthoboric acid, 5 parts by weight of potassium hydrogen phosphate, 1 part by weight of ethyl acetate.

A 15% aqueous solution of the following components is used for impregnation of wet wood:

Claims (1)

SUBJECT OF THE INVENTION Wood-based salt preservative, containing inorganic compounds of fluorine, boron, potassium, sodium and phosphorus, characterized in that it is a mixture of 35 to 65 parts by weight of potassium hydrofluoride, 1 to 45 parts by weight of sodium chloride or potassium chloride, 25 parts by weight of sodium tetraborate or orthoboric acid, 5 to 25 parts by weight of potassium hydrogen phosphate and 0 to 1.0 parts by weight of an ester surfactant.