NO164399B - WOOD PROTECTION AGENT AND USE THEREOF. - Google Patents

Description

The present invention relates to a wood preservative which contains water, copper or zinc complexes dissolved in water, and acid which binds copper or zinc in wood.

Previously known are wood preservatives that contain amine complex-forming metals, usually copper or zinc, as well as ammonia and carbonic acid. A similar wood protection solution can be prepared, for example, by reacting ammonia with copper carbonate, after which the formed solution is stabilized with ammonium carbonate and, if necessary, with carbonic acid.

Various substance mixtures based on, for example, copper or zinc are known as wood preservatives. Copper can then be bound in wood and also in other ways than by precipitation in the form of carbonate. The so-called CCA salts were developed in the 1930s and have since been widely used to protect wood against decay. Such CCA salts contain copper, chromium and arsenic. Copper is used because of its fungicidal effect, while arsenic is mainly used to produce an insecticidal effect. Chromium is again used to bind copper in wood. The CCA salts provide good protection against decay, but are harmful to the environment.

The disadvantage of these previously known wood preservatives is that they do not give the wood sufficient dimensional stability. This disadvantage has been tried to be eliminated by using water-insoluble wood preservatives, which are dissolved in an organic solvent for impregnation. Such organic solutions do not penetrate the wood as well as water solutions, organic solutions also increase the price of the wood preservative and make it highly flammable. By using microemulsions, the amount of organic solvent can be mixed, but such a microemulsion is, after all, significantly more expensive than a water solution.

The present invention has the so-called purpose of producing a water-based wood preservative which is cheap, non-toxic and penetrates well into the wood, which is not easily leached from the wood, and which causes water absorption in the wood to decrease.

The present invention also aims to produce a wood preservative in which the effect of copper and zinc is more effective than previously. The agent according to the invention can also be used in fungicidal paints, surface treatments and plant pots.

The main distinctive features of the invention appear from the attached patent claims.

Now it has unexpectedly turned out that the aforementioned objectives and benefits can be achieved with wood preservatives that contain water, water-dissolved copper and/or zinc complexes as well as an organic water-soluble or i.v. miscellarizing polymer that stabilizes copper and/or zinc in wood, which at least partially penetrates into. three sam* which'contain'acid— groups.

Zirconium complexes can also be used together with Cu and/or Zn complexes, as zirconium complexes increase the polymer's water resistance and reinforce the copper and/or zinc's effect against microorganisms. The Zr complex can be added as a separate salt, for example as ammonium zirconium carbonate or also prepared in a similar way as a Cu and Zn amine polymer acid complex.

As a compound that complexes copper or zinc, ammonia is advantageously used, but one can also use a primary, secondary or tertiary amine substituted with lower alkyl such as methyl, ethyl or propyl, or cyclic amine such as piperidine, morpholine or the like, as prepared in patent claim 4, whereby appearance in the wood of the copper or zinc polymer which dissolves poorly in water or is insoluble in water, comes from the complex former evaporating in the drying phase or the wood's acidic environment neutralizing the used complex former.

As an organic polymer, any such polymer can be used which partially or completely penetrates wood, which is water-soluble or miscellulates in water and which contains carboxyl groups, phenolic groups and/or

Pol = Polymer group (bond atom carbon)

R<1>= aliphatic, alicyclic or aromatic radical or a derivative containing these functional groups, or polymer

R = like R<1>and also H

The penetration of the polymer into the wood can be regulated with the molecular weight. If the polymer's molecular weight does not exceed 2,000, it penetrates completely into the wood and if the molecular weight is above this, only partial penetration occurs, whereby an over-surface impregnation is the result. This molecular weight limit varies for different polymers according to their configuration. For example, for polyethylene glycol, it is approx. 2,000.

The water solubility of the polymer is regulated by the degree of hydrophilicity, in other words by the number of acid groups or other hydrophilic groups, such as hydroxyl, amide or amine groups, it contains.

The polymer does not have to be completely water-soluble, it is sufficient if it is partially water-soluble, whereby it can be emulsified in water to form micelles. The polymer, which contains hydrophobic groups, also reduces the wood's

swelling.

The polymer can be synthetic or natural polymer. Radical polymers, condensation polymers or addition polymers can be used as synthetic polymers.

Examples of radical polymers include polymerizing (meth)acrylic itaconic, maleic, vinyl and (meth)allyl phosphonate, phosphoric acids and various arsenic acids. These acid groups can further be produced or bound by means of a suitable post-treatment reaction for the finished radical polymer, especially in the event that the suitable acid monomer is not commercially available.

As comonomers, for example, other (meth)allyl and acrylic compounds can be used, both hydrophobic (for example, vinyl alkyl ether or (meth)acrylic ester) and hydrophilic, and further monomers that contain other than hydrophilic functional groups, for example amido-, amino-, OH, halogen and nitrile groups.

Useful condensation polymers include polyesters, for example phosphoric acid diol esters or their derivatives, polyamides, amino resins, such as urea, melanin, cyanamide, guanidine, benzoguanamine resins, etc. which amino resins are produced by condensation with an aldehyde or ketone or with alcohol etherified aldehyde condensates, phenolic resins, especially resols, and possibly mixed polymers, provided that these contain one or more of the aforementioned acid groups.

Examples of addition polymers include polyethylene imine derivatives, polyurethane and polyethylene oxide derivatives.

Among natural polymers, mention may be made of lignosulfonate derivatives, starch derivatives, e.g. phosphorous strengthening, alginate, carboxymethyl cellulose, pectin and carrageenan.

The equivalent ratio of the acid groups in polymers and the copper or zinc in the complex is 1:10 to 10:1, preferably 1:2.

The wood preservative according to the invention advantageously contains approx. 0.05 to 0.08 moles of copper or zinc,

0.1 to 0.2 mol monovalent acid groups in the polymer and 0.2 to 0.4 mol NH3 in one liter of impregnation solution.

A particularly advantageous wood preservative is a water solution of zinc tetra-ammonium polyacrylate.

A particularly advantageous wood preservative is obtained when filicin extract of worm ferns, which is a mixture of phloroglycine derivatives, is added to the aforementioned mixtures.

In worm ferns (Filices) there are generally phloroglysine derivatives which are monocyclic filicic acids and aspidinols as well as di and tricyclic derivatives of these. Phloroglysin derivatives can be separated from ferns by extraction, and such an extract in which the phloroglysin derivatives form the most important components is called crude filicin and crude aspidin. Filicic acids, aspidinols and their derivatives are obtained pure from fern extract by separation, but they can also be produced synthetically. Until now, fern extract and its components have only been used as a means of combating pests such as rodents (cf. Fl explanatory note 54 850) and as a medicine against tapeworms and endoparasites.

It has now emerged that said fern extract can be used in mixtures according to the invention, whereby they increase the effect of the wood preservative against decay and insects.

The invention is illustrated in the following by means of examples.

Example 1

The impregnation solution is prepared by neutralizing polyacrylic acid (molecular weight 1,600), prepared from 2 mol of acrylic acid (144 g), with NaOH and by adding 1 mol (250 g) of copper sulfate to the neutralized solution. The precipitated copper polyacrylate is separated by filtration and 4 moles (272 g 25%) of ammonia are added. The obtained solution is diluted so that it contains 0.052 mol (3.3 g)Cu<2>+/l- This solution's fungicidal effect was tested with the mold-box method according to NWPC's (Nordic WoodPreservation Council) standard 1.4.1.2/ 70, whereby the following result was obtained.

Blocks of surface wood of size 2 x 2 x 1.5 cm<3> were impregnated with the solution described above. The impregnated blocks were allowed to drain, weighed, dried and weighed again. The bricks were buried in the soil and after 24 weeks they were examined.

The weight losses appear in the following table:

The weight loss for the bricks treated with Cu polyacrylate was slightly less than for the bricks treated with Kemira "K 33" and significantly less than for those treated with Cu naphthenate, although the Cu retention was lower in the acrylate. This refers to the synergistic effect of copper and polyacrylate.

In the leaching test, 12% of the Cu-c.lyacrylated copper was leached into the water.

Example 2

The impregnation solution was prepared analogously to example 1 from copolymer which was prepared from an acrylic acid-methyl methacrylate mixture, the copolymer contained 72 mol% methyl methacrylate.

Water absorption and dimensional change for the test pieces that were impregnated with the solution accounted for 60% of absorption and dimensional change for the untreated test pieces.

In the leaching test, 9% of the copper was leached into the water.

In the mold box test, the weight loss of the solution-impregnated bricks was the same as the bricks which were impregnated with the solution according to example 1.

Example 3

In a solution prepared in the same way as the solution in example 1, 0.014 mol of alkylammonium chloride was added. The impregnation's retention was 2 kg copper/m<3>surface wood. The weight loss of the impregnated bricks in the soil box test was 21% less than the weight loss of the untreated bricks. In the leaching experiment, 12% of the copper was leached into the water.

Example 4

A solution was prepared containing per liter 0.07 6 mol zinc, polymer prepared from 0.152 mol alkyl acid and 0.303 mol ammonia. The retention of the impregnation was 3 kg zinc/m<3>surface wood. The weight loss of the impregnated bricks in the soil-case trial was 30% less than the weight loss of the untreated bricks.

Example 5

A solution was prepared which contained per liter 0.052 mol of copper, copolymer made from 0.052 mol of maleic anhydride and 0.052 mol of styrene and 0.208 mol of ammonia. The impregnation's retention was 2 kg copper/m<3>surface wood.

Example 6

A solution was prepared which contained per liter 0.052 mol of copper, polymer made from 0.104 mol of vinyl sulphonate and 0.208 mol of ammonia. The retention of the impregnation was 2 kg copper/m<3>surface wood.

Claims (7)

1. Wood preservative containing water, copper and/or zinc complexes dissolved in water or copper- and/or zinc complex together with zirconium as well as acid which stabilizes said metals in wood, characterized in that the acid which stabilizes said metals in wood is a water-soluble or water-dissolving organic polymer which at least partially penetrates wood and which contains acid groups. 2. Wood preservative according to patent claim 1, characterized in that the pol/nier contains carboxyl groups, phenolic groups, phosphite groups, phosphate groups, phosphonate groups and/or groups of various arsenic acids and/or such derivatives of phosphoric acid and arsenic acids that contain at least one acid group (OH) . 3. Wood preservative according to patent claim 2, characterized in that the equivalence ratio for the acid groups in the polymer and the copper and/or zinc in the complex is 1:10 to 10:1, preferably 1:2 to 3:1. 4. Wood preservative according to one of the preceding claims, characterized in that the complexing substance is an easily volatile compound, in which R-j_, R2 and R3 means hydrogen or lower alkyl, or Rx + R2 means -(CH2)or -(CH2)n - X - (CH2)n where X = 0 or NR3, n = 2 or 3 and m = 5 or 6 . 5. Wood preservative according to one of the preceding claim, characterized in that it is an aqueous solution of copper and/or zinc tetra-ammonium polyacrylate. 6. Wood preservative according to one of the preceding claims, characterized in that it contains 0.05 to 0.08 mol of copper and/or zinc, 0.1 to 0.2 mol of polymer and 0.2 to 0.4 mol of ammonia in one liter of solution. 7. Use of a wood preservative as stated in claim 1 for surface treatment either alone or together with other binders, pigments and other additives, or as a fungicide, for example in paint and plant pots, which contains water, in water-dissolved copper and/or zinc complexes or copper and/or zinc complexes together with zirconium complexes as well as acid which stabilizes said metals in wood, which is a water-soluble or water-dissolving organic polymer whose molecular weight is lower than 2,000, and which at least partially penetrates wood, and which contains acid groups.