FI72454B - SALTHALTIGT TRAEKONSERVERINGSMEDEL. - Google Patents

Description

1 72454

Salty wood preservative

The invention relates to a saline, water-soluble wood preservative in which the toxic base is a compound of fluorine, boron, potassium, sodium and phosphorus.

The use of the above-mentioned inorganic compounds, in particular fluorine compounds and boron compounds, in the production of wood preservatives is known. The best known fluorine compounds used for wood protection are: sodium fluoride, potassium fluoride, zinc fluorosilicate, potassium bifluoride, ammonium bifluoride and ammonium fluoroborate. Fluorine compounds have been used alone for wood preservative (NaF), however, they are generally included as one component in wood preservative compositions.

15 Known wood preservatives, Wolman's salts, contain, in addition to fluorine compounds, chromium compounds (U-salts), chromium and arsenic compounds (UA salts, Ull salts). Bifluoride-based materials have also been prepared.

The use of boron compounds for wood protection corresponds to fluorine compounds in their field of application. Wood preservatives - Boliden's salts, "Wolmanit CB", disclosed in DD Patent No. 54,100, "Synpregnit CBZ," Soltox R-12 "- contain boron compounds in their compositions. Preservatives which, in addition to the above-mentioned compounds, contain boron compounds have the same properties as chromium and fluorine or the addition of sparingly water-soluble compounds containing chromium and boron to wood 30 immediately after impregnation deeper into the wood and the penetration of fluorine and boron even into very moist wood.The penetration depth of said substances varies in the range 2-4 mm for air-dry wood and 4-6 mm for moist wood when impregnation without pressure.

35 Bifluoride-based preservatives penetrate considerably deeper than the above-described preparations 72454 Da are characterized in that they continue to penetrate deep into the wood after the impregnation treatment. However, when wood is dried in the air, large amounts of gaseous hydrogen fluoride (I ^ F ^ evaporate from the impregnated wood, which is very harmful to the environment. Therefore, after impregnation with a preservative, the wood must be allowed to air for about 12 weeks before being used for construction purposes. points when using chromium and fluorine or chromium and boron are, the depth of penetration is small, the ability to penetrate after supersaturation of wood-10 and the permanent discoloration of wood are lacking.

The closest prior art is represented by e.g. FI application publication 791 928 and FI publication publication 61 320, the former describing the impregnation treatment of a cellulosic material with an aqueous solution containing phosphoric acid and ammonium sulphate and / or ammonium phosphate, and the latter a solution of cellulosic material or ammonia and sodium tripolyphosphate.

The wood preservative composition according to the invention is characterized in that the composition contains 35 to 65 parts by weight of potassium bifluoride, 1 to 45 parts by weight of sodium chloride and / or potassium chloride, 1 to 25 parts by weight of sodium tetraborate and / or orthoboric acid, 5-25 parts by weight of dibasic potassium phosphate and 0-1.0 parts by weight of surfactant selected from esters.

The saline preservative according to the invention is characterized by penetration deep into the wood (air-dry and moist wood) and does not change the natural color of the wood. Its water solubility is very high and it is odorless. The preservative according to the invention 30 is characterized by the ability to penetrate deeper after impregnation by diffusion. When wood is stored under conditions that prevent the moisture content of the wood from changing, the penetration depth of the preservative into air-dry wood increases by about 100% and in wetter wood by more than 35 100%. In impregnation processes without pressure and using diffusion, it is possible to achieve a penetration deeper than 20 mm when using the composition according to the invention. The preservative according to the invention effectively protects wood and its lignocellulosic material against the degrading effect of microorganisms and at the same time is characterized by a strong toxic effect against insects which are a scourge for the technological use of wood. By appropriately selecting the chemical compounds of the safener and precisely determining the amount of each ingredient, it is an experimentally developed safener whose bifluorides do not have a detrimental effect on the environment. Removing the main point of this group of preservatives - the evolution of hydrogen fluoride - is a substantial improvement.

The wood preservative according to the invention contains five components which are inorganic compounds: potassium bifluoride, dibasic potassium phosphate, sodium tetraborate or boric acid, sodium or potassium chloride and a surfactant. Said compounds have not previously been used as the above-mentioned combination as a wood preservative.

The addition of a surfactant obtained from the group of esters to said wood preservative improves the possibility of increasing the depth of penetration into the wood.

It has been found that the best results are obtained according to the invention in terms of 100 parts by weight of each ingredient in the following amounts: 25 - potassium bifluoride 35-65 parts by weight sodium chloride 1-45 parts by weight sodium tetraborate 1-25 parts by weight - dibasic potassium phosphate 5- 25 parts by weight of surfactant (of esters) 0 to 1 part by weight In the saline wood preservative according to the invention, sodium chloride can be partially or completely replaced by potassium chloride, sodium tetraborate can be partially or completely replaced by orthoboric acid. The preservative is used as a 5-15% aqueous solution.

The preservative according to the invention is presented in more detail by means of the following embodiments: 35 4 72454

Example 1

A 10% aqueous solution of the following ingredients is used to impregnate air-dried wood: 5 39% by weight of potassium bifluoride 45% by weight of potassium chloride - 4% by weight of sodium tetraborate 11% by weight of dibasic potassium phosphate 1% by weight of ethyl sulfuric acid 10

Example 2

A 15% aqueous solution of the following ingredients is used to impregnate moist wood: 15 to 32% by weight of potassium bifluoride 38% by weight of sodium chloride 6% by weight of orthoboric acid 23% by weight of dibasic potassium phosphate 1% by weight of ethyl acetate 20

Example 3

A 5% aqueous solution of the following ingredients is used to impregnate air-dried wood: 25 to 35% by weight of potassium bifluoride 25% by weight of sodium tetraborate 25% by weight of dibasic potassium phosphate 15% by weight of potassium chloride Example 4

A 15% aqueous solution of the following ingredients is used to impregnate wet wood: 45% by weight of potassium bifluoride 35 to 40% by weight of sodium chloride 9% by weight of orthoboric acid 5% by weight of dibasic potassium phosphate 1% by weight of ethyl acetate.