DE10340093A1 - Wood preservative based on bio-polymers, applied to timber as water-soluble basic copper and boron complexes - Google Patents

Abstract

The preservative is a watery solution of biopolymers on the base of hydro-colloids, together with ammonia and/or aminiac solutions of pref. copper and boron complexes. This is applied to the timber components to be protected, with/without additional impregnation for primary protection. Application is by painting, spraying, rolling, or impregnation. Metals of the groups 1B and 3A of the periodic system are pref. used for metal complex formation. Additional impregnation is provided by the addition of metallic salt solutions of the metals calcium, magnesium, zinc, aluminum, iron, chromium, resp. ammonium compounds.

Description

Documents considered for the assessment of the application:
OS DE 198 33 497 A1
OS DE 195 13 903 A1
OS DE 43 39 701 A1
OS DE 36 39 063 A1
OS DE 36 21 361 A1
OS DE 36 09 544 A1
PS DE 35 20 313 C2

The The present invention relates to a novel wood preservative with considerably prolonged Efficiency and excellent environmental compatibility based on biopolymers, as water-soluble basic copper and boron complexes applied to the cellulose fiber, by impregnation be converted into water-insoluble structures.

Around Wood from destruction by organisms and insect pests to protect, it must be treated with wood preservatives. There are in the Trade a big one Number of products. Allen is common: they only keep a limited one Time its effectiveness. Cause can be decomposition by aging, Evaporation of organic substances, leaching by water, but also destruction by UV light. In contrast, a combination of wood preservation often helps Active ingredients and addition of other additives, but the different Creep behavior of the individual components causes a time-dependent decay of wood preservation. Furthermore a number of the active substances used for the protection of wood are toxic, odor-intensive (tar oils), carcinogenic and environmentally harmful. The environmental compatibility is not only important during the wood preservation period, but also for the disposal of the impregnated Use wood.

New, suitable as wood preservatives substances must be specific to the wood-destroying organisms be effective against humans and the environment, however, over the period of their fixation and use on wood no damage cause.

Copper- and boron compounds are widely used in wood preservation. Of the Disadvantage of most based on inorganic copper compounds Wood preservatives is that after the wood coating when exposed to moisture a high leaching rate of about 10% to 100% of the copper occurs, wherein especially copper sulfate is extremely washed out. Organic copper compounds are only partially soluble in water, yet show in organic solvents dissolved Copper compounds only adsorptive adhesion to the cellulose fibers of the wood. Another disadvantage of all organic coating materials is their low penetration compared to the aqueous Coating materials, because those swell the wood fibers less can. To counteract leaching, known wood preservatives combined with other compounds, which in most cases however toxic side effects. Fungicidal basic substances with improved copper fixation using various triazole compounds are mentioned in the OS 43 39 701 and OS 195 13 903. The OS 36 21 361 and OS 36 09 544 claim wood preservatives based on copper with the addition of tributyltin compounds or thiocyanates and iodides. OS 36 39 063 claims a wood preservative on the base a copper compound and an aliphatic carboxylic acid the additionally contains a polyamine. DE Pat. No. 35 20 313 claims wood preservatives with copper and zinc complexes in conjunction with a zirconium complex. Are carriers organic polymers containing carboxyl or phenolic groups.

When boron-containing compounds are used in wood preservatives boric acid, borax, Combination preparations like Chromat-fluoride borate and chromate-copper salt-borate mixtures used. DE PS 30 23 612 claims a fungicidal wood preservative consisting of at least one organometallic boron compound, wherein the boron and at least one divalent metal via oxygen bridges with each other are connected, and at least one carboxylic acid radical and a suitable one carrier contains. Such materials are stable only in nonaqueous solutions. A reaction with the cellulose fibers is therefore excluded. DE PS 34 47 027 uses Copper-boron alkanolamine compounds, points out, however, that the connection made in the wood is washable with water. Another way describes the DE OS 198 33 479, which is a time-delayed Release of boron compounds by incorporation into an inorganic Describes metal oxide sol.

A possibility To prevent the leaching of treated wood is the aftertreatment with varnishes, glazes and waxes, which is only temporary Shows success and an additional Effort means.

aim a development of new wood preservatives with functional fungicidal (biocidal) copper and / or Borkomplexen must therefore be to reduce the release potential and thus compared to the state significantly improve the technology. This can be done by the firm fixation the biocidal metal ions are obtained on the wood fibers and leads with it to a significant improvement in the long-term effect.

Surprisingly succeeded in the production of nearly water-insoluble novel metal complexes by incorporating metal ions in one with the cellulose body of the Wood identical and / or related biopolymer matrix

The experiments have shown that taking advantage of the reactive groups of natural polymers such as -OH, -COOH, -OR, -NH ₂ , a ligation of biocidal metal ions, especially Cu ²⁺ and B ³⁺ , in the simultaneous presence of Ca ²⁺ , Mg ²⁺ , Zn ²⁺ , Al ³⁺ lead to new complex compounds that are almost insoluble in water, contain no organic solvents and their fixation takes place directly on the biopolymer fibers.

From the production of copper art silk is known that chemically pretreated cellulose is dissolved in an ammoniacal copper solution. The resulting compound according to K. Hess has the formula: [C ₆ H ₇ O ₅ Cu] ₂ [Cu (NH ₃ ) ₄ ], ie a copper cellulose anion and a copper tetrammine cation. In the development of wood preservatives with long-term effect was surprisingly found that it is possible with correct choice of reactants to dissolve both the untreated cellulose fibers of the wood, as well as to form an almost insoluble protective coat of the cellulose - copper complex to the wood fibers. The biocidal effect of the protective cover can be increased by the incorporation of additional cations - as stated above - by impregnation. The success of the invention is documented in the following examples, with blank values additionally being added for comparison

Example 1:

10 g of copper (II) sulfate pentahydrate ¹⁾ (CuSO ₄ .5H ₂ O); MW = 249.68; are dissolved in 234 g of water. The copper content of the solution is 1.04 wt .-%. The sample is for comparative reference only.

Example 2

20 g of copper (+2) sulfate ¹⁾ (CuSO ₄ .5H ₂ O); MW = 249.68; are dissolved in 80 g of water. Then, by adding 35 g of ammonia solution (25%), the deep blue Cu tetramminkomplex prepared and further diluted with 354 g of water. The copper content of the solution is 1.04 wt .-%. The sample is for comparative reference only.

Example 3

Solution 3a

8 g of alginate ²⁾ (= hydrocolloid based on polyuronic acid, MW = 32,000 to 250,000, a uronic acid unit MW = 176) are dissolved in 92 g of water with stirring on a dissolver at 1,500 rpm in 5 minutes. After another 5 minutes these are also solved. The total solution is adjusted to a pH of about 8 with ammonia solution (25%).

Solution 3b

20 g of copper (+2) sulfate ¹⁾ (CuSO ₄ .5H ₂ O); MW = 249.68; are dissolved in 80 g of water. Thereafter, the deep blue copper tetrammine complex is prepared by adding 35 g of ammonia solution (25%). The copper content of the solution is 3.77% by weight. The molar ratios of Cu / Ammin correspond to those in Example 2

Example 3.0.

76.6 g solution 3b is under mild stirring in 100 g of solution 3a introduced and in addition 100.2 g of water added. The result is a homogeneous deep blue Liquid. The molar ratio of copper to Uroneinheit of the polymer in the example 4 = 1: 1. Of the Copper content is 1.04%

Example 3.1.

38.3 g solution 3b is under mild stirring in 100 g of solution 3a introduced. The result is a homogeneous deep blue liquid. The molar ratio of copper to Uroneinheit of the polymer in the example 4 = 1: 2. Of the Copper content is 1.04%

Example 3.2.

153.2 g solution 3 b is stirred gently in 100 g of solution 3a introduced and in addition Added 301 g of water. The result is a homogeneous deep blue liquid. The molar ratio of copper to the uronic unit of the polymer is 4 = 2: 1 in the example. Of the Copper content is 1.04%.

Table for example 3, 3.1. and 3.2.

Example 4

Solution 4a

8 g of Na alginate ²⁾ (= polyuronic acid based hydrocolloid, MW = 32,000 to 250,000, a uronic acid unit MW = 176) are dissolved in 92 g of water with stirring on a dissolver at 1,500 rpm in 5 minutes. After another 5 minutes these are also solved. The total solution is adjusted to a pH of about 8 with ammonia solution (25%).

Solution 4b

76.6 g copper tetrammine complex according to Example 3b. The copper content is 3.77%.

Solution 4c

In 160 g of water are 40 g of boric acid ³⁾ (H ₃ BO ₃ ); MW = 61.84) while stirring and simultaneously adding 60 g of ammonia solution (25%). The forming ammonium borate forms a stable solution and has a boron content of 2.69%.

76.6 g solution 4b is under mild stirring in 100 g of solution 4a introduced and homogenized. Thereafter, the addition of 1.83 g of solution 4c. Finally is diluted with 97.8 g of water. The result is a homogeneous deep blue liquid. The solution has a Cu content of 1.04%, a boron content of 0.017%. The molar relationship of copper / boron / uronic unit of the polymer is 4 = 1: 1: 0.1 in the example.

Example 4.1.

corresponds to Example 4 with a subsequent impregnation by means of Ca ⁺² solution (according to Example 6)

Example 5

100 g solution 4a are mixed with 100 g of water and with 1.83 g of solution 4c with stirring homogenized.

By adding B ⁺³ ions, the originally water-soluble alginate loses its water-solubility ness. The dry film is much more resistant to moisture due to polymer cross-linking. The demonstrated principle of Example 5 was used in Example 4 closer.

Example 6

All Samples according to Examples 1-4 are applied to glass plates and ground Fir wood (grit sandpaper 320) in a wet film thickness of 200 μm applied. After a drying time of 24 hours at room temperature can the samples on the soluble Copper content to be examined.

The samples of Examples 3-4 prepared according to Example 6 are additionally impregnated with Ca or Al compounds. For this purpose, the samples applied according to Example 6 are impregnated after a drying time of 2 hours 5 minutes by immersion in the appropriate salt solution. The impregnating solution used was an aqueous calcium chloride ⁵⁾ solution (2%) and an aluminum chloride ⁶⁾ solution (2%). After the impregnation process, the samples are rinsed under running water for about 2 minutes.

Example 7

The applied on glass plates or applied and impregnated Samples according to Example 6 and 7 were after a storage period of 24 Hours on soluble Copper examined.

The coated in a wet film thickness of 200 microns on glass plates coating has a total surface area of 180 cm ² . All samples have a copper content of 2080 mg / m ² . The samples are extracted differently in time with water. In the water, copper ions are tested for Cu ions using the semi-qualitative Merckoquant Copper Test ⁷⁾ . The result is the following:

Example 8

The applied on fir wood or applied and impregnated Samples according to Example 6 and 7 were after a storage period of 24 Hours of outdoor weathering for 6 months. Additionally were the samples over this working day watered once in fresh tap water for 3 minutes. The result is basically identical to the release behavior according to example 8.

Rating scale: A = without infestation; B = little infestation (gray); C = infestation; D = strong algae gray; E = total algae (gray-green)

Example 9

It will be the solution 4a, the other solution according to Example 3.1. applied to glass plates with 200 microns. After drying for 2 hours at 20 ° C, the films are impregnated with 2% Ca ⁺² solution or with a quaternary ammonium compound ⁸⁾ .

The samples of Example 9 applied or applied to glass plates and impregnated were tested for solubility or soluble copper after a storage time of 24 hours (analogously to Examples 6 and 7). The result is the following:

Example 10

Solution 10a

In 192 g of water, 8 g of Walocel CRT 10,000 ⁹⁾ (= carboxymethylcellulose-based hydrocolloid); with stirring on a dissolver at 1500 rev / min in 5 minutes. After another 5 minutes these are also solved. The total solution is adjusted to a pH of about 8 with ammonia solution (25%).

Solution 10 b

In 192 g of water are 8 g of Carb ¹⁰⁾ (= hydrocolloid based on carboxypropylated guar); with stirring on a dissolver at 1500 rev / min in 5 minutes. After another 5 minutes these are also solved. The total solution is adjusted to a pH of about 8 with ammonia solution (25%).

Example 10.0.

corresponds to Example 3.0. It is a Cu-amine-alginate complex with 1.04% Cu.

Example 10.1.

76.6 g solution 3b is under mild stirring in 200 g of solution 10 a introduced. The result is a homogeneous deep blue liquid. The copper content is 1.04%.

Example 10.2.

76.6 g solution 3b is under mild stirring in 200 g of solution 10 a introduced. The result is a homogeneous deep blue liquid. The copper content is 1.04%.

The Samples 10.0., 10.1. and 10.2. be in the same thickness 200 microns ground on Fir wood (see Example 6) applied and 24 hours at room temperature dried.

In a second series, these woods were additionally impregnated with Ca ⁺² solution (according to Example 6). The impregnated panels were rinsed under running water for two minutes after impregnation.

After 24 hours, a copper test was completed. The following copper solubilities were found:

Example 11

It The treatment of sanded fir wood took place in steps.

Solution 11a

In 192 g of water, 8 g of alginate ²⁾ (= polyuronic acid based hydrocolloid, MW = 32,000 to 250,000, a uronic acid unit MW = 176); with stirring on dissolver at 1,500 rev / min in 5 minutes. After another 5 minutes these are also solved. The total solution is adjusted to a pH of about 8 with ammonia solution (25%).

Example 11.0.

• corresponds to step 1.

step 1: The copper ammine complex according to sample 2 was applied to ground fir wood in a thickness of 200 microns. Within 2 minutes, the material is absorbed.

Example 11.1.

• corresponds to step 1 and 2.

step 2: The alginate solution according to sample 11a was applied to the still moist wood surface at 100 microns and dried for 24 hours.

Example 11.2.

• corresponds to step 1, 2 and 3.

Step 3: After drying according to step 2, impregnation was carried out using Ca ^{+ 2} solution (5 minutes and subsequent water rinse according to Example 6).

Claims (5)

Production and use of novel wood preservatives with a particularly long protective action against wood pests, characterized in that aqueous solutions of biopolymers based on hydrocolloids, together with ammoniacal and / or aminic solutions of preferably copper and boron complexes, are applied to the wooden parts to be protected with or without a post-treatment for the purpose of impregnating the primary wood preservative. A method according to claim 1, characterized in that biopolymers are used with reactive groups such as -OH, -COOH, -OR, -NH ₂ for coordinative attachment of the metal ions. Method according to claim 1, characterized in that that metals of groups 1B are preferably used for metal complex formation and 3A of the periodic table according to the old IUPAC recommendation become. Method according to claims 1, 2 and 3, characterized that to the extra Impregnation of metal salt solutions of Metals Ca, Mg, Zn, Al, Fe and Cr, or quaternary ammonium compounds added can be. A method according to claim 1 to 4, characterized in that the solutions according to the invention with all the usual application methods - such as painting, spraying, rolling and impregnating - on wood be brought.