DK152263B - WOOD PRESERVATICE - Google Patents

Abstract

1. A wood preservative based on an aqueous mixture of boric acid and a water-soluble organic amine and additionally containing 40 to 80% by weight of sodium polyborate or a mixture of boric acid and borax.

Description

DK 152263 B

in

This invention relates to a wood preservative of the kind set forth in the preamble of claim 1.

It is known to use a concentrate with a high content of boric acid, e.g. a mixture of diethanolamine, 5 b.oric acid and water as a wood preservative (DE patent no. 21 40 051).

Using alkanolamines as a solvent for the boric acid, the concentrates can only be used as flame retardants under certain conditions.

10 These concentrates are highly hygroscopic and, despite initial drying, produce strong adhesive stresses on the wood for shorter or longer periods, depending on humidity and temperature.

When using other amines, e.g. polyamines, 15, there is too strong drying on the wood, so that the strokes in the long run become brittle and exhibit cracking. When used as a wood preservative for protection of the rim (ironing, spraying, dipping), in which the concentrate is diluted with 20 water (usually 90-75% by weight water), penetration of one of the boric acid in the wood is adversely affected by the lack of penetration of the amine which immediately binds to the surface of the tree.

The wood preservative according to the invention is peculiar to that of the characterizing part of claim 1.

It has been found that the wood preservative according to the invention does not suffer from the disadvantages mentioned above. The wood preservative according to the invention is suitable both for protection of the tree before attacks from fungi or insects and as a flame retardant for protecting the tree before fire due to fire.

DK 152263B

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For example, a water-soluble organic amine is understood to mean: primary, secondary, tertiary organic amine or diamine, triamine, tetramine or pentamine or a hydroxy derivative or methoxy derivative of the indicated 5 amines. Such amines are, for example, monoethanolamine, diethanolamine, triethanolamine, monomethylethanolamine, methyldiethanolamine, ethylamine, diethylamine, propylamine, methoxyethylamine, methoxypropylamine, dimethylethanolamine, 1,2-propylenediamine, 3-amino-1-methylaminopropane, dipropylene tripropylenetetramine, tetrapropylene pentamine or mixtures thereof. Monoethanolamine is preferred.

For most amines, boric acid stirring in the amines is sufficient. However, since the resulting 15 liquids may be too viscous, it is recommended to use a low water addition during processing.

Above a pH of approx. 6.5 to 7.5 allow the concentrate to be readily prepared. Under these pH values, dissolution of the boric acid in the amines or polyamines is made more difficult. A pH of approx. 7.5 to 8.0 corresponds to a mixing ratio of approx. 1 mole of amine to 3 to 4 moles of boric acid. In each case, the polyamines must contain approx. 1 nitrogen atom of the polyamine molecule reacts with 3 moles of boric acid, ie. for example, there is a mixing ratio of 1 25 moles of triamine to 9 moles of boric acid. By increasing the amine or polyamine content, higher pH values can be adjusted as needed.

Sodium polyborate (Na 2 B 2 O 3. 3 50) is a solid, water-soluble compound. It arises from reaction between 50 boric acid and borax in water. The wood preservative according to the invention may thereby contain sodium polyborate or 3

DK 152263B

is a mixture of boric acid or borax since, as indicated above, it is converted to sodium polyborate.

In the preparation of the wood preservative according to the invention, the addition of a mixture of boric acid and borax or the alternate addition of boric acid and borax to the aqueous mixture of the water-soluble amine and boric acid is preferred.

The wood preservative of the invention contains, as indicated, 20 to 60% by weight of a concentrate of the usual mixture of boric acid and a water-soluble organic amine. To this is added 40 to 80% of sodium polyborate or preferably of the equivalent amount of the boric acid and borax mixture. The weight ratio of boric acid to borax in the added mixture is suitably 2: 1 to 1: 1.2, preferably 1: 1.

The wood preservative of the invention is e.g. a viscous wood and fire protection paste having a total content of 40 wt% ^ is * '/ and of a temperature of 20 ° C has a solubility of over 25 °.

For example, the paste is prepared. by slow stirring of sodium polyborate in the mixture of boric acid and amine or by stirring boric acid / borax in this mixture.

Thereby, during the stirring process, reaction occurs between boric acid and borax during the decomposition of water sodium polyborate, which precipitates in a very fine crystalline form (1 to 10 µm) and then forms the paste together with the mixture of boric acid and amine.

The mixture ratio in the boric acid / borax mixture is selected depending on the pH of the boric acid / amine 30 mixture such that the wood preservative of the invention and its aqueous solutions exhibit a pH between 6 and 8 at 20 ° C. For the wood preservative of the invention more or 4 can be added as needed

DK 152263B

less water to set the desired viscosity.

The addition of thickening and thixotroping agents can improve the sedimentation conditions or the iron-on properties of the wood preservative.

EXAMPLE 1

Boron amine concentrate 1, consisting of: 20 parts (parts by weight) of monoethanolamine 60 parts of boric acid 10 20 parts of water.

Wood preservative, consisting of: 33 parts boron amine concentrate 1 67 parts borax / boric acid 1: 1.

Preparation: The boron amine concentrate is filled into a stirrer and alternately boric acid and borax are added with stirring. The stirring process is maintained for so long that the boric acid or borax crystals have dissolved and the sodium polyborate has formed and has separated.

20 Iron-on coatings on wood (300 - 450 g / m applied in two workflows) dry very quickly. They are not hygroscopic, and after a long period of time, they exhibit neither adhesive nor brittle properties.

25 Ironing ratio as a fire protection agent 2 Application: 350 g / m.

Storage at approximately 75 ° C humidity / 20 ° C - duration 4 weeks.

5

DK 152263B

Boron amine concentrate 1 Wood preservative according to Example 1: adheres strongly to Dryer without cracking, drying is not brittle, does not adhere 5 and this layer acts insulating on the underlying tree. The normally combustible wood is difficult to burn because of the ironing.

Penetration as a wood preservative.

Samples are sprinkled with 10? Aqueous solutions and after 7 days the depth of penetration is determined when testing the tree with turmeric reagent.

Boron amine concentrate 1 Wood preservative according to Example 1: Application 50 g Concentration - Application 50 g / m funnel / m, medium depth penetration penetration (fiber saturated) 3.6 mm 6.2 mm Example 2

Boron amine concentrate 2 15 parts diethylenetriamine 20 parts water 65 parts boric acid 25 Wood preservative consisting of: 50 parts boron amine concentrate 2 50 parts boric acid / borax (1,2: 1) 6

DK 152263B

Preparation as in Example 1.

Ironing conditions as a fire protection agent.

7 Application: 350 g / m.

5 Storage at approx. 65¾ humidity / 20 ° C - duration 4 weeks.

Boron amine concentrate 2 Wood preservative according to Example 2 - r *

After drying: After drying: 10 dry with cracking dry without cracking, not crisp, not sticking

Penetration as a wood preservative.

Sample pieces of wood are coated with 10¾ solutions in water, and after 7 days the penetration is determined by turmeric reagent.

Boron amine concentrate 2 Wood preservative according to Example 2_

Average penetration penetration (fiber saturated) 3.2 mm 6.0 mm 20 Colored coatings or wood preservative solutions can be prepared by the addition of pigment preparations or dyes. By adding humectants, the initial wetting of the wood is improved with the wood preservative.

Claims (2)

Wood preservative with a high boric acid content based on a concentrate of an aqueous mixture of boric acid with a water-soluble organic amine, characterized in that the wood preservative 5, in addition to 20-60% of the concentrate, further contains 40 to 80¾ sodium polyborate or a hereby equivalent amount of a mixture of boric acid and borax. Wood preservative according to claim 1, characterized in that it contains boric acid and borax 10. the weight ratio of 2: 1 to 1: 2, wherein the boric acid present as salt of the organic amine is not taken into account.