CH623503A5 - Process and composition for protecting wood against fungal attacks - Google Patents

Description

The present invention relates to a method and a composition for protecting wood against attack by fungi capable of destroying it.

It is well known that certain sulfenylimides have a marked fungicidal action against plant-destroying fungi. Among these, we can mention:

0

the Captane n

(VI)

N-S-CC12-CFC12

and

30

\ /

(VII)

N-S-CClg-CFClg,

We have now surprisingly discovered that the strong reduction in fungicidal activity against wood-destroying fungi which is observed when the fluorine of compound VII is replaced by hydrogen, which gives Difolatan, does not take place when, in compounds IV, V and VI, fluorine is replaced by hydrogen, which gives compounds I, II and III: 40 I. Nl, l, 2,2-Tetrachloroethylthio- N-phenylmethanesulfon-amide

CH3-S02-N-S-CC1o-CHC1,

II. N, N-Dimethyl-N '- (1,1,2,2-tetrachloroethylthio) -N'-phenylsulfamide

CH

3 \

CH ^

N-S02-N-S-CC12-CHC12

Ó

It is also known that these fungicides effective against plant fungi have only very moderate activity against wood-destroying fungi, such as Coniophora cerebello, Polyporus vaporarius and Merulius lacrymans.

It has been mentioned that the compound of formula:

III. N-1,1,2,2-Tetrachloroethylthiophthalimide

0

II

VS

(IV)

oc>

-S-CC12-CHC12

II

0

3

623 503

In other words, it has been found that compounds I, II and III act very well against wood destroying fungi.

Consequently, the present invention provides a method for preserving wood against attack by fungi, characterized in that it is treated with an effective amount of at least one of the compounds I, II or III above .

The invention also includes an antifungal composition for implementing this process, characterized in that it comprises at least one of compounds I, II and III incorporated into a filler or diluent suitable for the treatment of wood.

To treat the wood with at least one of compounds I, II and III, any process and, preferably, a method known in the practice, such as those described, for example, in the technical literature, can be used. Suitable methods can be found in, for example, F.P. Kollmann and Wilfred A. Coté Jr., "Principles of Wood Science and Technology", vol. 1, chap. 5, pp. 136-157, Springer Verlag, New York (1968) and F.P. Kollmann, Wilfred A. Coté Jr. and Alfred J. Stamm, "Principles of Wood Science and Technology", vol. 2, chap. 2, pp. 107-111. Springer Verlag, New York (1975). As such suitable methods, mention is made, for example, of surface treatment methods (such as painting and immersion), methods by displacement of sap (such as the Butchery method) and methods of impregnation by soaking in a tank (such the methods of Riipingon Riitger).

In all these methods, the treatment composition preferably contains 0.1 to 10% by weight of active compound or compounds, better still from 0.1 to 4%. The parameters of the composition, and in particular the concentration of the ingredients, will be chosen according to factors such as: type of wood, use for which it is intended, degree of protection required, treatment method (for example painting or impregnation under pressure ); however, tradespeople will have no trouble choosing a preferred composition or method of treatment.

To prepare suitable compositions according to the invention, it is possible, for example, to add at least one of compounds I, II and III to any of the liquids usually used for the protection of woods, this liquid preferably being an organic medium wherein the active compound is soluble at the desired concentration. It is possible to use a hydrocarbon or a mixture of hydrocarbons, preferably aliphatic containing, if desired, a small proportion of liquid aromatic hydrocarbons or neighboring compounds. Preferably, white spirit, petroleum or other commercial liquid hydrocarbons are used.

It is possible, if desired, to incorporate into the composition an agent for binding the active compound to the wood. Such binders are known in the art and include, for example, alkyd resins, linseed oil and other substances capable of forming films. The suitable concentrations of such binders will depend, as before, on the same factors mentioned with regard to the concentrations of the active ingredients, and may range, for example, up to 10% by weight or even more.

The compositions according to the invention which are particularly preferred are liquid and comprise approximately 4% by weight of at least one of the compounds I, II and III, approximately 9% by weight of a binder in the form of conventional alkyd resin, and about 87% by weight of white spirit.

The compositions according to the invention can also be obtained by mixing at least one of the compounds I, II and III with a self-emulsifiable oil or a wettable powder; such compositions can be used as is done for agricultural fungicides.

The compositions according to the invention are useful for protecting all kinds of wood susceptible to attack by destructive fungi, such as: pine wood, fir, beech in the form, for example, of stakes, posts, boards, beams and all other forms usable in construction.

Compounds I, II and III can be prepared, for example, by reacting 1,1,2,2-tetrachloroethylthiosulfenyl chloride with a suitable amide or imide. We can prepare these bodies,

in particular, according to the descriptions of the German patent applications DOS Nos 1800836 and 1801203 and the US patent USP No. 3796802, respectively, as regards the fluorinated compounds IV, V and VI.

The compositions of the invention are more advantageous than those containing the following compounds, known and used for the protection of wood: pentachlorophenol, tributyl tin oxide and dichlofluanide, because the activity of compounds I, II and III is much stronger against wood-attacking fungi. These compounds I, II and III are also more advantageous than fluorinated compounds IV, V and VI, because the latter are easier to manufacture and cheaper than the latter, in particular because the chloride of 1,1,2, 2-tetrachloroethylthiosulfenyl is more readily available than 2-fluoro-1,1,2,2-trichloroethylthiosulfenyl chloride.

Another advantage of compounds I, II and III is that they are less toxic to mammals than fungicides such as pentachlorophenol, tributyl tin oxide and dichlorofluanide and fluorinated compounds IV, V and VI.

The following examples are given in order to better illustrate the invention. Percentages are by weight unless otherwise indicated.

Example 1

The activity of compounds I, II and III and the other above compounds was measured as fungicides for wood against Coniophora cerebello.

For this, pine wood plates of 7 x 1.6 x 0.2 cm were prepared, dried for 24 hours at 103 ° C. and weighed.

The compounds to be tested were dissolved in ethyl acetate containing 9% of an alkyd binder at the following concentrations: 4,2,1,0,5,0,25 and 0.125%. In these solutions, the samples were quickly soaked to impregnate them. By weighing it was established that the absorption was approximately 100 kg of solution per m3 of wood. Then the plates were dried 2 days at room temperature. After drying, three samples of each strength were packed in sterilizable plastic bags and sterilized by X or gamma rays.

Glass bottles containing 500 ml of soil specially fertilized to promote the growth of Coniophora cerebello were sterilized for 3 h in an autoclave at 120 ° C. A sample of wood and an untreated control plate were placed in each bottle, then the soil of Coniophora cerebello was inoculated and incubated for four weeks at 22 ° C and 70% relative humidity.

After this period, the plates were carefully brushed, dried and weighed. Weight loss was expressed as a percentage of the initial weight. In cases where this loss was less than 20%, the test was disregarded and repeated.

The figures in the table indicate, as an average of three samples, the weight loss (in percent).

(Table at the top of the next page)

Example 2

Test of general fungicidal activity by action against Pullulano pullulons and Aspergillus niger, these microorganisms being reputed to cause the blackening of painted objects and the formation of stains on wet textile products.

The compound to be tested was dissolved in ethyl acetate and 0.3 ml of this solution was regularly deposited on a filter paper (Whatman No. 40) with a surface area of 19.5 cm 2. After evaporation of the solvent, the paper was placed in a petri dish containing agar and this medium was inoculated with a suspension of spores of the appropriate fungus. After 10 days at 29 ° C and 85% relative humidity, the contents of the box were examined. Samples showing no signs of growth of the fungus were marked positive except for a narrow border at the edge of the paper.

The following compounds have been tested and the table gives the results as the minimum concentration of fungicides allowing a positive result. ->

5

10

15

20

25

30

35

40

45

50

55

60

65

623 503

4

Compound

4%

2%

Concentration of active compound (% w / v)

1% 0.5% 0.25%

0.125%

LD50 g / kg oral,

mouse

F

(° C)

Pentachlorophenol

2

6

18

> 20

> 20

> 20

0.1

Tributyl tin oxide

0

0

0

4

> 20

> 20

0.2

Dichlofluanide

1

1

1

12

> 20

> 20

ca 1.0

I

0

0

0

0

3

9

10

129

II

0

0

0

3

9

16

10

114

III

0

0

0

0

6

12

10

111-116

Captan

4

8

> 20

> 20

> 20

> 20

ca9

Folpet

6

11

13

18

> 20

> 20

10

Difolatan

9

11

13

18

> 20

> 20

ca 6

IV

0

0

0

0

0

6

ca 3

V

0

0

0

0

1

5

10

VI

0

0

0

0

2

6

-

VII

0

0

0

0

0

2

ca3

Compound

P. pullulions

A. nig

Pentachlorophenol

0.5

1

Tributyl tin oxide

0.5

1

Dichlorfluanide

0.05

0.05

I

0.05

0.005

not

0.5

0.005

m

0.05

0.05

Captan

0.1

1

Folpet

0.02

0.1

Difolatan

0.005

0.005

IV

0.05

0.05

V

0.5

0.05

VI

0.05

0.05

VII

0.005

0.005

R

Claims (3)

623 503 1. Method for protecting the wood against attack by fungi, according to which it is treated with an effective amount of a fungicide, characterized in that it consists of at least one of the following compounds: Nl, l , 2,2-tetrachloroethylthio-N-phenylmethanesulfonamide, N, N-dimethyl-N '- (1,1,2,2-tetrachloroethylthio) -N'-phenylsulfamide, and N-1,1,2,2- tetra-chloroethylthiophthalimide. 2. Composition for carrying out the method according to claim 1, comprising a fungicidal agent and a filler, or diluent, characterized in that the fungicidal agent consists of at least one of the following compounds: Nl, l, 2 , 2-tetrachloroethylthio-N-phenyl-methanesulfonamide, N, N-dimethyl-N '- (1,2,2,2-tetrachloroethyl-thio) -N'-phenylsulfamide, and N-1,1,2, 2-tetrachloroethylthiophthalimide. N-S-CC1 3 * 0 the Folpet N-S-CC1, and Difolatan 0 he .vs \ / N-S-CClg-CHClg. CH5-S02-N - S-CC12-CFC12 has a high activity against wood destroying fungi and that such a property is also that of the compound of formula: CH 3 \ CH. N-S02-N-S-CC12-CFC12 (V) as well as compounds described in US Patent No. 3,796,802, of formulas: