DK167383B1 - CONCENTRATE FOR IMPROVING MASSIVE TREES, PROCEDURE FOR PRINTING PREPARATION WITH Aqueous SOLUTION PREPARED FROM THE CONCENTRATE AND PROCEDURE FOR PREPARING AN IMPROVING SOLUTION - Google Patents

Abstract

1. A concentrate for impregnating solid wood in order to preserve the latter, based on a copper salt and monoethanolamine and, if required, a salt with a fungicidal anion, wherein the concentrate contains from 5 to 50% by weight of monoethanolamine and, if required, further alkali such that a pH of not less than 8 is established.

Description

in DK 167383 B1

The invention relates to a concentrate for impregnating (solid) wood on the basis of an inorganic copper salt, mono-ethanolamine and optionally a salt with a fungicidal active anion such as a boric acid salt or boric acid.

5

For the protection of wood exposed to weather and wind or humidity or placed in contact with earth, chromate-containing, fixing wood preservatives have been used heretofore. These wood preservatives are used as usual, e.g. 2 to 6% solutions corresponding to the impact to which the wood to be impregnated is later exposed, and also by means of high-tech impregnation systems (boiler pressure impregnation).

15 For use in cases where soil contact occurs, only because of the necessary effect against decomposing organisms are agents used which in addition to chromate also contain copper. The CK type (base copper, chromium, boron), CKF type (base copper, chromium, fluorine), CKA type (base copper, chromium, arsenic) are differentiated.

These wood preservatives fix via the chromium fraction: the chromates react after impregnation with the wood's components, reducing to III-valent chromium compounds, thereby increasing the pH of the wood to precipitate copper and chromium compounds in the wood as water-insoluble compounds; they are fixed.

30

Chromates, ie VI-valent chromium compounds, however, represent a significant risk to the environment when leaching or the influence of weather and wind during the fixation process, leaching occurs so that surface, ground and drinking water are contaminated; the maximum value of the concentration that is currently considered tolerable is e.g. at 0.05 ppm. Also, in the case where the chromium in the wood is in the insoluble III-valent form, it can again be oxidized by combustion to VI-valent chromium compounds which can then be leached from the ash; This causes environmental problems.

5

So far, chromium-free, copper-containing, water-soluble wood preservatives have been proposed for high-tech impregnation, whereby e.g. copper arsenates and borates were transferred to water-soluble alkaline form by complexing with ammonia; by evaporation of the ammonia and buffer action from substances contained in the wood (the wood's own pH value is about 5), these agents are fixed in the wood. Irrespective of odor nuisance, these impregnation solutions or concentrates may lose their stability by evaporation of ammonia, so that the solutions are no longer suitable for further impregnation. In addition, an insufficient ammonia content inhibits the penetration of the protective agent into the wood.

20

Amines are also recommended, e.g. ethylene diamine, which has good complexing properties, for wood preservatives containing copper and fluorine for the protection of wood materials (including, for example, particle board); by these means, the glue is mixed in a highly concentrated form and sprayed onto the chips. They are not suitable for full tree protection because the ethylene diamine complexes are also resistant to the tree's intrinsic pH (5-6) and are not fixed; they are washed out with water in the tree.

30

Copper fixation only succeeds when organic, water-insoluble copper salts can occur. Thus, wood preservatives containing copper salts of N-nitroso-cyclohexyl-hydroxylamine (new termed copper salt of N-cyclohexyl dioxide diazenium oxide, Cu-HDO) have been described. Cu-HDO is transmitted via polyamines, e.g. ethylene diamine or diethylenetriamine for wood preservative concentrations which are dissolved in water for the purpose of impregnation. They are fixed in wood by buffer action until pH approx. 7.5 using substances contained in the tree. However, this fixation takes place so rapidly that the penetration of 5 Cu-HDO is prevented by boiler pressure impregnation. Thus, even with slightly permeable pine, only Cu-HDO is obtained in an outer layer of approx. 10 to 15 mm; the distribution of protective agents from the outside and the inside decreases rapidly.

If other amines, e.g. alkanolamines, especially monoethanolamine, are used for complexation, Cu-HDO is only completely dissolved in highly concentrated solutions, and by dilution with water to use concentration it precipitates again.

15

It has now been found that the aforementioned disadvantages can be eliminated with a concentrate of the kind specified in the preamble of claim 1, which is peculiar to the characterizing part of claim 1.

20

The water-diluents contain - in concentrated form - the copper, calculated as an element, generally in an amount of between 1 and 15% by weight.

Suitable concentrates contain e.g. (in each case wt%): 5 to 50% copper salt 5 to 50% alkanolamine 30 to 50% salt of a fungicidal anion up to 5% free alkali, the sum in each case being 100 (wt%), and optionally subordinates quantities of other constituents, such as amines, ammonia, corrosion inhibitors, and, if necessary, water, the proportion of which, however, can generally be kept at a low value, and which essentially serve handling matters. The invention also relates to boiler pressure impregnation of wood which is characterized by the characterizing part of claim 3, as well as a method for preparing an impregnating solution for use in this impregnation which is characterized by the characterizing part of claim 4.

The complexation can take place in the presence of fungicidal anions, such as e.g. borates or fluorides. By dissolving the copper compounds in monoethanolamine, optionally during water addition, highly concentrated water-soluble pastes or liquid concentrates which can be dissolved in water arise and in this form can be used for impregnating wood. The pH of the aqueous impregnations is at or above 8, especially between 8 and 9 (concentration dependent). In the impregnation by the boiler pressure method, the copper components penetrate well into the wood. The wood preservatives according to the invention are subjected to cushioning effect by impregnation due to the wood acids present in the wood, copper precipitates from approx. pH = 7 in the tree; namely, the complexing power of monoethanolamine from pH = 7 to 7.5 is no longer sufficient to keep the copper in solution so that the copper is fixed. The copper fixation is in the same order of magnitude as for the 25 hitherto used chromate and copper containing wood preservatives, ie. at least 85% are fixed and on average 90 to 95% of the copper components in the wood. The fixation is thus partly dependent on the additional alkanolamine content necessary to adjust the pH of 30 strong acids or fungicidal anions; but a certain proportion of pH shifting effect can also be obtained by the addition of e.g. alkali liquor, e.g. as much as is necessary for a displacement corresponding to 1 pH unit. In general, this precaution relates to the proportion of fungicidal anions 35 or acid residues; independently of the complexation, the pH adjustment can also be made to the required value by means of alkali, ammonia or other water-soluble <amines.

Monoethanolamine is used as a complexing agent. The amount of the added alkanolamine is adjusted in such a way that it is sufficient on the one hand to complex the copper (1 gram atom of copper generally needs 4 mole equivalents of amine) and, on the other hand, alkanolamine salts of the additional fungicidal anions used (fluoride, borate, fluoroborate) or acid esters such that a pH of 8 or more, preferably about 9 to 10, is introduced into the aqueous impregnation solution.

4

For the purposes of the practical test of the invention, proceed as follows: The concentrates were diluted with water in the amount indicated in each case to obtain ready-to-use solutions containing 3-4% by weight of the original concentrate and small pine blocks were impregnated with these solutions.

20

After drying, the said small bricks were washed for 4 weeks with distilled water, changing the water daily. Then it was found how much copper was washed out.

EXAMPLE 1

Of a concentrate of

33.3% by weight CuSO4 .SI2O

33.3 wt.% Monoethanolamine 33.4 wt.% Water and with pH 9.9 1, in each case, 40 g was dissolved in water to form 1 liter, the pH of which is 9.4, (hereinafter referred to as "4% aqueous solution ").

DK 167383 B1 6

Copper leaching 7.5% EXAMPLE 2 From a concentrate of 20.0% by weight of SCuCOH + CuCu 40.5% by weight monoethanolamine 40.0% by weight water and at 10 pH 12.2 a 4% aqueous solution of pH 10 was prepared. 2nd Copper leaching 10.5%.

EXAMPLE 3

From a concentrate of, 15.0 wt% CuiOH ^ CuCOg 20 16.0 wt% monoethanolamine 16.0 wt% aminoethylethanolamine 25.0% H3B03 38.0% H30 and with * pH 10.1 25 a 4% solution of pH 9.3 was prepared. leaching:

Cu 10.5% B 85.5% 30 Example 16738 EXAMPLE 4

From a concentrate of 5 13.5% Cu (OH) 2 25.0% boric acid 17.5% monoethanolamine 17.5% aminopropanol 26.5% water and at 10 pH 10.5 a 4% solution with pH 9.5 was prepared. leaching:

Cu 7.7% B 86.5% * EXAMPLE 5

From a concentrate of 20 50% Cu (BF 3) solution (50% dissolved in water) * 30% monoethanolamine 20% h 2 O and with pH 8.1 25 a 3% solution was prepared as previously defined with pH 8.9. Leaching: ”

Cu 10.5% 30 F 70.0% B 75.0% · * 35 8 DK 167383 B1 EXAMPLE 6 Of a concentrate of 5 16.5% Cu (OH) 2CuCo3 10.0% nh4hf2 36.0% monoethanolamine 3.5% H2O and at pH 9.8, a 3% solution of pH 9.2 was prepared. leaching:

Cu 0.5% F 78.5% EXAMPLE 7

From a concentrate of 15.0% Cu (OH) 2CuCo3 30.0% aminoethanolamine 25.0% boric acid 27.0% H2O and at pH 11.8 25 a 4% solution of pH 9.8 was prepared. leaching:

Cu 12.5% B 88.0% EXAMPLE 8

From a concentrate of 70% copper borate paste (50% dispersed in water) 30% monoethanolamine and at pH 11.4, a 4% solution of pH 9.6 was prepared. leaching:

Cu 7.5% B 85.0% EXAMPLE 9

From a concentrate of 10 75% copper borate paste (50% dispersed in water) 25% monoethanolamine and at pH 11.4 a 4% solution of pH 9.6 was prepared. Leaching: 15

Cu 6.2% B 66.1% X * COMPARATIVE EXAMPLE 1 (not according to the invention) 20

Chromium salts:

la) Type CKB

Content of Cu 8.6% 25 Content of Cr 13.4%

Content of B 4.4%

(lb) Type CKF

Content of Cu 7.7% 30 Content of Cr 25.5%

Content of B 14.5% la) Type CKB Leaching in%

Cu 8.0% 35 Cr 2.0% B 93.5% 10 DK 167383 B1 lb) Type CKF Leaching in%

Cu 13.5%

Cr 18.5% F 72.5% 5 COMPARATIVE EXPERIMENT 2 (not according to the invention)

12.0% CuO

22.0% ethylenediamine 12.0% KHF2 54.0% water 3% dissolved in water

Leaching: 15

Cu 75.5% F 92.5% 20 25 30 35

Claims (3)

Concentrate for impregnating solid wood on the basis of an inorganic copper salt, monoethanolamine and optionally a salt with a fungicidal anion, characterized in that it contains 5-50% by weight of monoethanolamine and optionally additional alkali in such an amount that by diluting the concentrate with water to a usual treatment concentration of approx. 1 to 5% by weight of the concentrate in the aqueous solution adjusts to a pH of at least 8. Concentrate according to claim 1, characterized in that it further contains a boric acid salt or boric acid. A process for boiler pressure impregnation of wood, characterized in that an aqueous solution prepared from the concentrate according to claim 1 or 2 is used which contains a copper salt and monoethanolamine and exhibits a pH of 8 or more. Process for preparing an impregnation solution for the process according to claim 3, characterized in that a concentrate according to claim 1 or 2 is diluted with water or diluted a concentrate of an inorganic copper salt and optionally an alkanolamine with water. and adjusting the pH of the solution to 8 or greater by the addition of monoethanolamine and optionally alkali.