MXPA97006748A

MXPA97006748A - Preservativo de la mad

Info

Publication number: MXPA97006748A
Application number: MXPA/A/1997/006748A
Authority: MX
Inventors: Shiraishi Tetsuji; Nagano Yukihiro; Niino Noriaki; Sugai Yoshiaki
Original assignee: Lomb & Haasu Japan Kk; Zaiensu:Kk
Priority date: 1997-03-10
Filing date: 1997-09-04
Publication date: 1998-11-16

Abstract

New compositions that preserve the wood, which have a high resistance to molds, are disclosed. These compositions contain a combination of a compound of the isothiazolone and at least one water-soluble copper complex, formed of water-insoluble copper salts of copper oxides, which has been solubilized with at least one nitrogen-containing compound, selected from ammonia, ammonium and ammonium salts

Description

WOOD CONDOM BACKGROUND OF THE INVENTION The present invention relates to a preservative of wood, with excellent chemical stability, which prevents the wood from rotting, as well as the formation of molds on wood. Wood is used in a wide range of applications, for example, as a structural material, as an industrial material and in civil engineering. It is difficult to use for applications of prolonged periods, especially outdoors, because it is subjected to deterioration through rotting caused by organisms that break down the wood. Previous types of wood preservatives contain water-soluble copper compounds. The problem with water-soluble copper compounds is that, when these compounds are impregnated into the wood, subsequent exposure to rainwater tends to wash them out, and thus they have a problem in their use outdoors. To remedy this, alkaline wood preservatives were proposed, in which the water-soluble inorganic copper compound (comprised of at least one type selected from copper salts or copper oxides) is solubilized by the formation of a complex that uses ammonia, ammonium salts or amines.

When these water soluble complexes are used, the resulting wood preservatives have excellent cost effectiveness, very good application properties and are effective against wood destroying organisms, for example Coriolus versicolor and Serpula lacrymans; however, such condoms are not effective against some types of molds, for example, peni cillium and asarum. In addition, the alkaline component of such compositions provides a nitrogen source that promotes the growth of molds. While unlike decay, the growth of molds on wood does not affect its resistance, but if it contaminates the surface and is aesthetically inconvenient, thus drastically damaging its commercial value. The use of isothiazolone compounds in wood preservatives has been proposed to protect wood materials from molds; however, as isothiazolone compounds, which are used as anti-mold agents for wood, have poor chemical stability in alkaline aqueous solutions, and it is difficult to add properties against molds by mixing these compounds in conventional wood preservatives, such as the inorganic copper complexes, previously described, in aqueous alkaline solutions. This poor chemical stability of the isothiazolone compounds, when intermixed with conventional wood preservatives, has limited the commercial success of such combined products. SUMMARY OF THE INVENTION The present invention is directed to an alkaline composition for preserving wood, comprising: at least one isothiazole compound, selected from the group consisting of 2-methyl-4-isothiazolin-3-one, 2-octyl -4-isothiazolin-3-one and 4,5-dichloro-2-octyl-4-isothiazolin-3-one; at least one water-insoluble copper complex, which is formed by solubilizing a water-insoluble copper or copper oxide salt with a nitrogen-containing compound, selected from the group consisting of ammonia, ammonium salts and amines; and water. Brief Description of the Drawing Figure 1 is a cross section of the mold test system in the field. Figure 2 is the location of the test specimens in the mold test system in the field. Detailed Description of the Invention The present invention is based, in part, on the surprising discovery that certain isothiazolone compounds are stable in wood-preserving alkaline compositions, such as those containing water-soluble copper complexes. When applied as part of these wood preservative compositions, these isothiazolone compounds are not leached from the wood, but remain stable there, and also impart excellent properties against molds to these compositions that preserve the wood. Water-soluble copper complexes, useful in the compositions of the present invention, are conventionally formed by solubilizing copper salts or water-insoluble copper oxides, with the use of nitrogen-containing compounds, selected from ammonia, ammonium salts and amines Examples of water insoluble copper salts, suitable for use in the water-soluble copper complexes of this invention, include, but are not limited to: basic copper carbonate, basic copper acetate, basic copper nitrate, basic copper phosphate, basic copper chloride and copper pyrophosphate. Basic copper carbonate, basic copper phosphate and copper pyrophosphate are preferred. Examples of a copper oxide which is insoluble in water and suitable for use in this invention, include, but are not limited to, cupric oxide. Nitrogen-containing compounds, suitable for solubilizing copper salts insoluble in water or copper oxides, include, but are not limited to: ammonia, ammonium salts, such as ammonium bicarbonate, and amines, such as monoethanol- amine, diethanol-amine, triethanolamine, ethylene diamine, 1,2-propanediamine, 1,3-propanediamine, N, N-dimethylethylene diamine and N, N-diethylethylene diamine. In general, the wood preservative alkaline compositions according to the present invention should have a pH of from 8 to 13. The concentration range of the isothiazolone compound that is intermixed there is, from both cost and efficiency perspectives, 10 to 10,000 ppm. When the wood is saturated, the minimum effective concentration of the isothiazolone is 10 ppm or more, preferably 30 to 200 ppm. The wood preservative compositions of the present invention can be applied to the surface of the wood to be treated, incorporated into the wood by immersion, or impregnated under an application element at suitable pressure, or as such or after a further dilution in water or an organic solvent and water. The wood preservative compositions of this invention can be prepared, for example, by the following method. At least one type of copper compound, selected from copper salts or copper oxides insoluble in water, is first dispersed in water. Then, at least one type of nitrogen-containing compound, selected from ammonia, ammonium salts or amines, is added to the dispersion of one or more copper compounds, to cause this one or more inorganic copper compounds to form complexes and dissolve in the water. Then, 2-methyl-4-isothiazolin-3-one, 2-octyl-4-isothiazolin-3-one or 4,5-dichloro-2-octyl-4-isothiazolin-3-one, is mixed in the alkaline aqueous solution resulting from the one or more copper compounds, to obtain the preservative composition of the wood. Adjuvants known to those skilled in the art can be added to the preservative compositions of the wood of the present invention, as necessary or convenient. The following examples are presented to further illustrate various aspects of the present invention, but are not intended to limit the scope of the invention in any aspect. Example 1 The following is a description of a method for preparing wood preservative compositions, according to the present invention. Samples 3, 7, 9, 10, 14 and 16 of Table 2 are examples of preservative wood compositions, according to the present invention, the remaining samples are comparative.

Solution A (preparation of the copper compound) A-l Basic copper carbonate 16 25% ammonia water 63 Ammonium bicarbonate 9 water 12 100 (% by weight) A-2 Basic copper carbonate 18 monoethanol-amine 36 water 46 100 (% by weight) Solution B (preparation of the isothiazolones) Preparations of isothiazolones were obtained with the isothiazolone compounds, expressed in the following formula: wherein: X1 and? 2 are hydrogen or halogens; and R is an alkyl group. The formulations for isothiazolone, which contain the various isothiazolone compounds, are shown in the following Table 1. Table 1: Formulations of Isothiazolones PP = propylene glycol Emulsifier + polyoxyethylene-nonylphenyl ether (equilibrium value of the metabolic index / 1-phoenix [HLB] of 10) Table 2 * Preparations according to the present invention.

Example 2: Test Against Molds in Field A. Specimens and Chemical Treatment Thirty (30 pieces) of pinecone (1 x 10 x 50 cm) were placed inside a covered 70 liter pressure vessel and subjected to a treatment chemical, according to the following procedure. 1) The test specimens of the pinnata were placed in a pressure vessel and the cover closed. The pressure was reduced by a vacuum pump to 0.08 MPa and maintained for 30 minutes. 2) While continuously operating the vacuum pump, the chemical solution, previously prepared, was introduced into the container and this container was filled with the chemical solution. 3) Compressed air was then charged to the container and this container was subjected to a pressure of 0.7 MPa. The pressure was maintained for three hours. After that, the pressure was released and the solution was removed from the container. 4) The atmospheric pressure inside the vessel was then reduced to 0.08 MPa. This condition was maintained for thirty minutes and then the test specimens were removed.

B. Mold Testing Referring now to the Drawing, Figure 1 shows the cross section for the test system against molds in the wood preservative field of the present invention, and Figure 2 shows the location of the test samples within of the test system against molds in the field. As shown in Figure 1, the field mold test system 10, used in this invention, consisted of concrete blocks, the, Ib, lc, Id, a water tub 2 and polyethylene sheets 3a, 3b . The test against molds in the field was carried out according to the following procedure, which uses the test system 10 against molds in the field. Concrete blocks were placed separated by a certain distance. These concrete blocks were covered by a polyethylene sheet 3a. The water tub 2 was placed on the polyethylene sheet 3a between the concrete blocks la and la. Test specimens 4, treated with wood condom formulations, were grouped in 5-row x 6-piece packages and placed on concrete blocks Ib, fifty centimeters from the nearest bulk. The lc concrete blocks were placed and the polyethylene sheet 3b was added to cover the entire test system, in order to accelerate the growth of molds. The concrete blocks Id were then placed on both ends of the polyethylene sheet 3b. After 1.5 and 3 months, the growth of molds in each specimen was measured, according to the classifications described in Table 3. The percentages of the property against molds were calculated by the following formula, where the total number of test specimens was 30. Percentage (%) of property against molds = (total number of test specimens with damage <1) x 100 (total number of test specimens) Table 3: Evaluation of Damage Classification A classification of damage was determined as having an activity against molds, since in actual use, this slight generation of molds does not cause any problem. The results, presented as a percentage of the property against molds, are shown below in Table 4. Table 4 * Fomulation of the present invention These results clearly indicate that the compositions of the present invention, Formulations 3, 7, 9, 10, 14 and 16, exhibited excellent activities against molds, while the comparative compositions (Formulations 1, 2, 4- 6, 8, 11-13) exhibited poor or only one activity against molds likely. That is, the combination of an alkaline wood preservative, Al or A-2, with an isothiazolone Bl (2-methyl-4-isothiazolin-3-one), B-2 (2-octyl-4-isothiazolin-3) -one) or B-7 (4,5-dichloro-2-octyl-4-isothiazolin-3-one) showed excellent mold activity, while the combinations of Al or A-2 with the other isothiazolones was much less effective in the activity against molds. The preservative compositions of the wood of the present invention provide an excellent protection from the microorganisms that rot the wood, as well as a protection from molds that dirty the surface of the wood.

Claims

CLAIMS 1. An alkaline composition that preserves wood, which comprises: (a) at least one compound of an isothiazolone, selected from the group consisting of 2-methyl-4-isothiazolin-3-one, 2-octyl-4 isothiazolin-3-one and 4,5-dichloro-2-octyl-4-isothiazolin-3-one; (b) at least one water-soluble copper complex, formed by solubilizing a water-insoluble copper or copper oxide salt with a nitrogen-containing compound selected from the group consisting of ammonia, ammonium salt and amines; and (c) water.
2. Composition, according to claim 1, wherein the water insoluble copper salt is selected from the group consisting of: basic copper carbonate, basic copper acetate, basic copper nitrate, basic copper phosphate, basic copper chloride , and copper pyrophosphate.
3. Composition, according to claim 2, wherein the water insoluble copper salt is selected from the group consisting of: basic copper carbonate, basic copper phosphate and copper pyrophosphate.
4. Composition, according to claim 1, wherein the nitrogen-containing compound is an ammonium salt comprising ammonium bicarbonate.
5. Composition, according to claim 1, wherein the nitrogen-containing compound is an amine, selected from the group consisting of: monoethanolamine, diethanolamine, triethanolamine, ethylene diamine, 1,2-propanediamine , 1,3-propanediamine, N, N-dimethylethylene diamine and N, N-diethylethylene diamine.
6. Composition, according to claim 1, wherein the concentration of the isothiazolone compound in the preservative composition of the wood is from 10 to 10,000 ppm.