NO137426B - MEASURE FOR PROTECTION OF WOOD. - Google Patents

Description

The present invention relates to an active ingredient combination which is suitable for protecting wood and wood materials against destruction due to fungi and insects.

It is known that organic tin compounds such as e.g. tributyltin oxide. or triphenyltin acetate has fungicidal properties. Chlorinated hydrocarbons such as e.g. dichlorodiphenyltrichloroethane, hexachlorocyclohexane or endosulfan have a good insecticidal effect, but none or a very unsatisfactory fungicidal effect.

It has now been found that the fungicidal effect of organic tin compounds can be increased significantly by the simultaneous use of endosulfan. The effect of the mixture according to the invention on wood-discoloring or wood-decomposing fungi is significantly greater than for the organic tin compound alone, even though the second mixture component endosulfan alone has no effect on the growth of fungi. This increase in effectiveness for the organic tin compounds is attributed to a synergism for the two active substances.

The fungicidal properties of active substances are determined using a nutrient substrate test. Gradual amounts of the active substance are thereby incorporated into the nutrient base. These are infected with test fungi (ascomycetes and basidiomycetes) which are cultivated. The additions at which the growth of the test fungi is completely inhibited are the minimum inhibition concentration (MIC value). The following table contains these values as a percentage of the total amount:

Test mushrooms:

1. Alternaria consortiale

2. Auriobasidium pullulans

3. Aspergillus niger

4. Penicillium funiculosum

5. Chaetomium globosum

6. Coniophora puteana

7. Lenzite's abietina

8. Poria monticola.

The mixtures according to the invention show far better MHK values than the individual components used. TBTO has e.g. in the case of Alternaria consortiale an MHK value of 0.00596. The mixture of TBTO with ES in a ratio of 1:1 should theoretically give

an MHK value of 0.01%. However, the practical value is 0.001%, which corresponds to a business increase of 1000%.

At a mixing ratio of ES : TBTO of 4:1, the MHK value should be 0.025%. A value of 0.001% was found.

Also when examining the mixture according to the invention in accordance with DIN 52.176 (brick test) the synergistic control for the business becomes clear. In this test, pine splinter tissue blocks are soaked with solutions containing graduated amounts of active substances. The blocks are exposed for 3 months to attack by the wood-destroying fungus. The threshold values for the business are determined by two numbers. The highest number describes the lowest concentration at which attack no longer occurs. The lower number represents the concentration at which it was just possible to detect a treble layer.

The increase in business was not to be expected, all the more so as endosulfan obviously does not show any fungicidal effects. However, it is of the greatest practical importance and opens up the possibility of lowering the application concentration of the organotin compounds. This is of significant importance both because of the toxicity of this group of active ingredients and from economic considerations. The longer protection time that can be achieved by using the agents according to the invention is also of significant practical importance.

The use of the agents according to the invention can take place in a usual and per se known manner, as they e.g. are added to coating materials for the wood. The simplest way is to dissolve the active substance combination in petrol to a concentration of 0.1 - 5% and then to paint the wooden parts, and spray them or to dip them. Film-forming substances, artificial or natural resins, oil or waxes can also be added to coating agents containing active substances according to the invention, so that the primers usually found in practice are present. Furthermore, aqueous application forms are possible, whereby it is necessary to ensure that suitable auxiliary solvents or emulsifiers are used in order to achieve a good active ingredient distribution. The active substance concentration can vary, within the range 0.1% - 5% and is chosen according to need.

Example 1:

20 parts endosulfan and 10 parts tributyltin oxide are dissolved in 70 parts test petrol. This active ingredient concentrate is used to make ready-made wood protection fungicides. The amount of addition is chosen so that the content of active substances is between 0.1 and 5%.

Example 2:

For a fast-boiling petrol fraction (boiling point

180 - 200°C) 0.6 parts by weight of endosulfan, 0.9 parts by weight of triphenyltin acetate and 0.5 parts by weight of tributyltin oxide are added. Due to the solvent's high boiling point, good penetration and a long-lasting effect are achieved.

Example 3 '

To protect freshly cut wood, a mixture of 75 parts butyl glycol, 24 parts water, 0.5 parts tributyltin oxide and 0.5 parts endosulfan is prepared. With this mixture, freshly cut and barked trees are protected against a primary attack by fungi. At the same time, the use of endosulfan provides protection against insect attack.

Example 4:

A solvent-based wood stain has the following

composition:

Add 5 parts of the active ingredient concentrate specified in example 1 to this wood glaze. This agent is used to coat wooden formwork, window frames, mandrels, etc. Example 5:

A water-dilutable primer with the composition:

has an outstanding depth effect. The building timber which has been treated with this is protected against destruction due to fungi and insects.

Example 6:

A water-dilutable wood protection varnish consisting of:

serves for surface protection against attack by fungi and insects. To this wood protection varnish add 1 part by weight of wood protection

biocide consisting of 0.6 parts tributyltin fluoride and 0.4 parts endosulfan.

Claims (3)

1. Agent for the protection of wood, characterized in that it consists of a mixture of a) endosulfan (a,p-1,2,3,4,7,7-hexachlorobicyclo-(2,2,1)-heptene-( 2)-bisoxy-methylene-(5,6)-sulphite) and b) a trialkyl or triaryl tin compound. 2. Wood preservative according to claim 1, characterized in that the components are present in a ratio of 1:5 to 20:1, preferably 1:1 to 4:1. 3. Wood preservative according to claims 1 and 2, characterized in that it consists of an endosulfan and tributyltin oxide (hexa-n-butyl-distanoxane).