A METHOD OF TREATING TIMBER

Abstract: The invention relates to the treatment of timber and particularly to a method of fixing the active termiticide/fungicide component of boric acid within timber to be treated. The method includes chemically reacting the boric acid with a substance that contains an amine group component as a radical and that can solidify through polymerisation, forming the borate form of the substance. This borate form of the substance can then be dissolved in a solvent and applied to timber to be treated, evaporation of the solvent permitting solidification of the borate form of the substance through polymerisation thereof, thereby providing for the active termiticide/fungicide component of the boric acid to be attached to the timber for the protection of the timber.

Description: A METHOD OF TREATING TIMBER A METHOD OF TREATING TIMBER THIS INVENTION relates to a method of treating timber and to a treatment composition for use in this method. Boric acid is known to be an environmentally acceptable and effective termiticide/fungicide for use in the treatment of timber. However, in respect of timber used in soil and particularly when exposed to wet soil conditions, boric acid will quickly leach from the timber and, as such, become ineffective. Accordingly, it is an object of this invention to provide a method of fixing the active termiticide/fungicide component of boric acid within timber in order to render it effective over extended periods of time, particularly in relation to timber to be used in subsoil conditions, i.e. to render it non-leachable while maintaining its biocidal action. According to the invention there is provided a method of fixing the active termiticide/fungicide component of boric acid within timber for treatment of the timber, which includes the steps of chemically reacting boric acid with amine groups of a substance selected from a group consisting of a synthetic substance and a biological substance, that can solidify through polymerisation and that contains an amine group component as a radical, thereby linking the active termiticide/fungicide component of the boric acid with the said selected substance via the amine group component; forming a solution including the said selected substance having the active termiticide/fungicide component of the boric acid linked therewith and a solvent; applying the solution formed to the timber to be treated; and inducing evaporation of the solvent and solidification of the said selected substance having the active termiticide/fungicide component of boric acid linked therewith through polymerisation thereof. The method may include inducing evaporation of the solvent and solidification of the said selected substance by the application of heat and optionally, to enhance solidification, by catalysis with the use of a suitable catalyst. Also, the method may include applying the solution to the timber in a manner that the timber is effectively penetrated by the solution. Further according to the method of the invention, the said selected substance may be a synthetic polymer in the form of a polyester including the primary amine group NH 2 . The polyester particularly may be formed so that through its chemical reaction with boric acid, a polyester borate is formed. Also, the solution may be formed by dissolving the polyester borate in one of acetone and styrene acting as solvent. Alternatively, in accordance with the method of the invention, the said selected substance may be a biological polymer in the form of a protein and through its reaction with boric acid the borate form of the protein is formed. The protein typically is a denaturable protein in the form of egg white. As such, the solution including the borate form of the protein may be formed by dissolving the borate form of the protein in water. Still further according to the invention, the protein, during its chemical reaction with boric acid, may be mixed with a second biological polymer, not containing an amine group, but with inherent fungicidal properties, that can simultaneously react with the boric acid, forming a water soluble, polymerisable, mixture of the protein borate and the borate form of the second biological polymer. The second biological polymer may be a poiyflavonoid tannin, and the chemical reaction with the boric acid may provide a protein borate/tannin borate mixture. Still further according to the invention, the protein, during its chemical reaction with boric acid, may be mixed with a water borne resin containing its own amine group, the water borne resin reacting simultaneously with the boric acid to form the borate form of the resin, which also is water soluble. The water borne resin may be urea glyoxal. The invention extends also to a composition for use in a method of fixing the active termiticide/fungicide component of boric acid with timber for treatment of the timber, which comprises the composition formed from chemically reacting boric acid with a substance that can solidify through polymerisation and that contains an amine group as a radical and through which chemical reaction the termiticide/fungicide component ofthe boric acid is linked with the said substance via the amine group. The composition may be a synthetic polyester borate obtained from chemically reacting boric acid with a polyester including the primary amine group NH 2 . This composition may include one of acetone and styrene as a solvent in which the synthetic polyester borate is dissolved. Alternatively, the composition may be the borate form of a biological protein obtained from chemically reacting boric acid with the protein. This composition may include water as a solvent in which the borate form of the biological protein is dissolved. Still alternatively, the composition may be the borate form of an inherently anti-fungal mixture of a biological protein and a biological but inherently anti-fungal poiyflavonoid tannin obtained from reacting boric acid with the protein and the poiyflavonoid tannin. Also this composition may include water as a solvent in which the borate form of the biological protein and the poiyflavonoid tannin is dissolved. Still altematively, the composition may be the borate form of a biological protein, a biological but inherently anti-fungal polymer, and a water borne resin containing its own amine group, obtained from reacting boric acid with the protein, the anti-fungal polymer and the water borne resin. The anti-fungal polymer may be poiyflavonoid tannin while the water borne resin may be urea glyoxal. Also this composition may include water as a solvent in which the borate form of the biological protein, the anti-fungal polymer and the water borne resin is dissolved. The invention still further extends to a method of treating timber which includes providing the composition as defined above, dissolved in a solvent therefor, applying the solution to the timber to be treated and inducing evaporation of the solvent and solidification of the composition through polymerisation thereof. Within this method, evaporation of the solvent and solidification of the composition may be induced by exposing the timber to heat. In addition, solidification of the composition may be induced by catalysis with the use of a suitable catalyst. The individual steps associated with the method of fixing the active termiticide/fungicide component of boric acid within timber for treatment of the timber may be carried out in various different manners and the invention extends also to methods including these variations which still incorporate the essential principles of the invention as defined. The method of the invention including the benefits associated with the application of the method are described in more detail hereinafter with reference to the following examples. According to a first example of the invention, a method of fixing the active termiticide/fungicide component of boric acid with timber for the treatment of the timber includes firstly the step of chemically reacting boric acid with a synthetic polyester including the primary amine group NH 2 . Typically, the polyester may be a two- component polyester, the individual components having the following structures: -OC-CH =CH-COO-CH 2 -CH 2 -00 2 -0- and with the polyester including 20% of the structure A and 80% of the structure B. With the formulae of structures A and B respectively being C 16 H 15 0 8 N and C 10 H 10 O 4 N, the combined molecular weight is 230. The molecular weight of boric acid (H 3 B O 3 ) is approximately 62 and as the polyester usually will be only 60% pure, 383 grams polyester will be required to be linked with 62g boric acid, provided that the boric acid behaves monoprotically. Although boric acid is triprotic, it is in fact suspected that within the above chemical reaction with polyester it will behave monoprotically. In practice, the above proportional quantities of boric acid and polyester, with the boric ac'd saturated in water, are allowed to chemically react, an exothermic reaction resulting requiring continuous cooling. When the reaction is completed an aqueous layer of material can be decanted from a polyester layer, the polyester layer comprising essentially the required polyester borate substance, the chemical reaction being represented as follows: R" - NH 2 + H 3 BO 3 > R" - NH 3 + H 2 BO 3 ' where R" represents the polyester. SUBSTITUTE SHEET (RULE 26 The next step in the method of treating timber includes dissolving the polyester borate produced into an organic solvent such as acetone or styrene, the concentration of polyester borate being determined by the quantity of termiticide/fungicide to be fixed in the timber to be treated for the effective treatment thereof, as well as the 'porosity' of timber, i.e. the volume of Iiquid that can be forced into timber to ensure that the entire timber body is exposed to the Iiquid and, in practice, to the termiticide/fungicide. This aspect clearly is greatly variable and may be determined by the type of timber to be treated and the purpose of treatment. Furthermore, the Iiquid may include a standard catalyst, or a radical initiator such as cobalt, to catalyse solidification of the unsaturated polyester. The actual application of the solution formed is conventional as for known timber treatment processes involving a Iiquid organic solvent borne termiticide/fungicide, or the like, the timber being exposed to heating subsequent to application in order to provide for the separation of the solvent via evaporation and the solidification of the polyester borate within the timber by polymerisation thereof. In accordance with the method as above described, timber can be effectively treated with the termiticide/fungicide component of boric acid, which is known to be particularly effective. In its linked form with polyester and as a result of the polyester polymerisation, the said termiticide/fungicide component of the boric acid is effectively fixed within the timber, thus rendering treatment effective over extended periods of time, i.e. the termiticide/fungicide component of boric acid is rendered non-leachable while it still retains its biocidal action. In addition, as a result of the polymerisation of the polyester borate, timber treated is simultaneously hardened and the method of the invention thus also provides for an effective method of hardening timber simultaneously with the treatment thereof. Hardening is particularly effective when styrene is used as a solvent. According to a second example of the method of the invention, the biological substance that can solidify through polymerisation and that contains an amine group component as a radical is a protein, e.g. a denaturable protein such as egg white. Linking of the protein, which includes an amine group, with boric acid to form the borate form of the protein essentially can take place as before, with the protein borate form being soluble in water as a solvent, the water rendering the composition particularly environmentally acceptable. The application of the dissolved protein borate is conventional as for known timber treatment processes involving a water borne Iiquid termiticide/fungicide, or the like and the heating of the timber can be carried out as before, once again providing for exposure of a complete timber body to the termiticide/fungicide component of boric acid while timber treated is at the same time somewhat hardened as a result of the polymerisation of the protein. It will be appreciated that different proteins could be suitable for the above purpose as they all incorporate an amine group as part thereof. According to a third example of the method of the invention, an inherently fungicidal, biological mixture that can co-solidify through polymerisation and that contains an amine group component as a radical is provided, the mixture comprising a protein and inherently fungicidal poiyflavonoid tannin which can react with boric acid at the ether oxygen of the pyran ring of the flavonoid leading to condensation with a flavonoid in another tannin unit. Linking of the protein, which contains the amine group, and poiyflavonoid tannin with boric acid to form the mixture of protein borate and tannin borate essentially can take place as before, with the protein borate/tannin borate mixture being soluble in water as a solvent, which is again environmentally unacceptable. The application of the dissolved mixture of the borate form of protein and the borate form of tannin to timber and the heating of the timber can be carried out as before, once again providing for exposure of a complete timber body to the termiticide/fungicide component of the boric acid while timber treated is at the same time increasingly hardened as a result of the polymerisation and co-solidification of the protein/tannin mixture with cross¬ linking and networking of the material. It will be appreciated that different proteins and different poiyflavonoid tannins could be suitable for the above purpose as the former all incorporate an amine group as part thereof and the latter are all inherently antifungal and can all condense and polymerise in the mixture with boric acid. According to a fourth example of the method of the invention the inherently fungicidal, biological mixture that can co-solidify through polymerisation and that contains an amine group component as a radical is a mixture of protein, inherently fungicidal poiyflavonoid tannin which can react with boric acid at the ether oxygen of the pyran ring of the flavonoid as above, and a water borne resin which is chemically effective by having its own amine group for reaction with and complexation of the boric acid, for example a urea-glyoxal resin which is also physically effective by hydrophobation. Linking of the protein and the poiyflavonoid tannin with boric acid can take place as before, with the protein borate/tannin borate mixture being soluble with the resin and resin borate in water as a solvent. Once again a composition that is particulariy environmentally acceptable is provided The application of the dissolved mixture of the borate form of protein, the borate form of tannin and the borate form of resin to timber and the heating or catalysis of the timber can be carried out as before, once again providing for exposure of a complete timber body to the termiticide/fungicide component of the boric acid while timber treated is at SUBSTITUTE SHEET (RULE 261 the same time much hardened as a result of the polymerisation and co-solidification of the protein/tannin/resin mixture with cross linking and networking of the material. In addition to contributing to increased hardness and dimensional stability of the timber, the resins in general will also increase the hydrophobicity, or water-repellence, of the timber rendering it increasingly resistant to any loss of boric acid and consequent onset of microbial decay over longer time periods under wet conditions. It will be appreciated that different proteins and different chemically effective resins could be suitable for the above purpose as they all incorporate an amine group as part thereof, and different poiyflavonoid tannins and different physically effective resins could be suitable for the above purpose as they are inherently antimicrobial and all these polymers can condense and polymerise in the mixture with boric acid. The invention clearly extends also to the compositions formed in accordance with the method as above described as such and, particularly, to a polyester borate and to a protein borate, to a protein borate/tannin borate mixture and to a protein borate/tannin borate/ resin borate mixture which is particularly suitable for the treatment of timber. Still further, the invention extends to the above compositions in their dissolved form in a suitable solvent with the solution being particularly suitable for the treatment of timber. Cleariy, the above compositions can be provided in a suitable form for the treatment of timber requiring merely the application thereof to timber and subsequently the heating of the timber in order to permit solvent separation and recovery and polymerisation of the main composition within the timber. The invention accordingly extends also to a method of treating timber which includes providing a composition as envisaged above and, if not already dissolved in a suitable solvent, dissolving the composition in a suitable solvent. The dissolved composition can then be applied to timber to be treated in a conventional manner, whereafter the timber can be heated for separating and recovering the solvent therefrom and for permitting solidification of the composition by polymerisation thereof. It will be understood that the invention can apply also to other substances that can polymerise and that include an amine group which permits linking with boric acid in order to form the borate form of the substance, provided that the composition formed can dissolve in a suitable solvent permitting its application to timber as herein envisaged. Clearly, different chemical reactions can occur in order to provide for the above, whereas the remaining steps of the method also are greatly variable in order to permit the application of the composition formed to timber, while still incorporating the essential principles of the invention as are hereinabove defined and described.

Claims: CLΛIMS 1. A method of fixing the active termiticide/fungicide component of boric acid within timber for treatment of the timber, which includes the steps of chemically reacting boric acid with amine groups of a substance selected from a group consisting of a synthetic substance and a biological substance, that can solidify through polymerisation and that contains an amine group component as a radical, thereby linking the active termiticide/fungicide component of the boric acid with the said selected substance via the amine group component; forming a solution including the said selected substance having the active termiticide/fungicide component of the boric acid linked therewith and a solvent; applying the solution form to the timber to be treated; and inducing evaporation of the solvent and solidification of the said selected substance having the active termiticide/fungicide component of boric acid linked therewith through polymerisation thereof. 2. A method as claimed in Claim 1, which includes inducing evaporation of the solvent and solidification of the said selected substance by catalysis with the use of a catalyst. 3. A method as claimed in Claim 2, which includes inducing solidification of the said selected substance by catalysis with the use of a catalyst. 4. A method as claimed in any one of the preceding claims, which includes applying the solution to the timber in a manner that the timber is effectively penetrated by the solution. 5. A method as claimed in any one of the preceding claims, in which the said selected substance is a synthetic polymer in the form of a polyester including the primary amine group NH 2 . 6. A method as claimed in Claim 5, in which the polyester is formed so that through its chemical reaction with boric acid, a polyester borate is formed. 7. A method as claimed in Claim 6, which includes forming the solution by dissolving the polyester borate in one of acetone and styrene acting as solvent. 8. A method as claimed in any one of Claims 1 to 4, in which the said selected substance is a biological polymer in the form of a protein and, through its reaction with boric acid the borate form of the protein is formed. 9. A method as claimed in Claim 8, in which the protein is a denaturable protein in the form of egg white. 10. A method as claimed in Claim 9, which includes forming the solution by dissolving the borate form of the protein in water. 11. A method as claimed in any one of Claims 8 to 10, in which the protein, during its chemical reaction with boric acid, is mixed with a second biological polymer, not containing an amine group but with inherent fungicidal properties, that can simultaneously react with the boric acid, forming a water soluble, polymerisable mixture of the protein borate and the borate form of the second biological polymer. 12. A method as claimed in Claim 11, in which the second biological polymer is a poiyflavonoid tannin, and the chemical reaction with the boric acid provides a protein borate/tannin borate mixture. 13. A method as claimed in any one of Claims 8 to 12, in which the protein, during its chemical reaction with boric acid, is mixed with a water borne resin containing its own amine group, the water borne resin reacting simultaneously with the boric acid to form the borate form of the resin, which also is water soluble. 14. A method as claimed in Claim 13, in which the water borne resin is urea glyoxal. 15. A composition for use in a method of fixing the active termiticide/fungicide component of boric acid within timber for treatment of the timber, which comprises the composition formed from chemically reacting boric acid with a substance that can solidify through polymerisation and that contains an amine group as a radical and through which chemical reaction the termiticide/fungicide component of the boric acid is linked with the said substance via the amine group. 16. A composition as claimed in Claim 15, which is a synthetic polyester borate obtained from chemically reacting the boric acid with a polyester including the primary amine group NH 2 . 17. A composition as claimed in Claim 16, which includes one of acetone and styrene as a solvent in which the synthetic polyester borate is dissolved. 18. A composition as claimed in Claim 15, which is the borate form of a biological protein obtained from chemically reacting boric acid with the protein. 19. A composition as claimed in Claim 18, which includes water as a solvent in which the borate form of the biological protein is dissolved. 20. A composition as claimed in Claim 15, which is the borate form of an inherently anti-fungal mixture of a biological protein and a biological but inherently anti-fungal poiyflavonoid tannin obtained from reacting boric acid with the protein and the poiyflavonoid tannin. 21. A composition as claimed in Claim 20, which includes water as a solvent in which the borate form of the biological protein and the poiyflavonoid tannin is dissolved. 22. A composition as claimed in Claim 15, which is the borate form of a biological protein, a biological but inherently anti-fungal polymer and a water borne resin containing its own amine group, obtained from reacting boric acid with the protein, the anti-fungal polymer and the water borne resin. 23. A composition as claimed in Claim 22, in which the anti-fungal polymer is poiyflavonoid tannin. 24. A composition as claimed in Claim 22 or Claim 23, in which the water borne resin is urea glyoxal. 25. A composition as claimed in any one of Claims 22 to 24, which includes water as a solvent in which the borate form of the biological protein, the anti-fungal polymer and the water borne resin is dissolved. 26. A method of treating timber which includes providing a composition as claimed in any one of Claims 16, 18, 20 or 22, dissolved in a solvent therefor, applying the solution to the timber to be treated and inducing evaporation of the solvent and solidification of the composition through polymerisation thereof. 27. A method as claimed in Claim 26, in which evaporation of the solvent and solidification of the composition is induced by exposing the timber to heat. 28. A method as claimed in Claim 27, in which solidification of the composition is induced by catalysis with the use of a catalyst. 29. A method of fixing the active termiticide/fungicide component of boric acid within timber for treatment of the timber substantially as described. 30. A composition for use in a method of fixing the active termiticide/fungicide component of boric acid within timber for treatment of the timber, substantially as described. 31. A method of treating timber which includes the use of a composition as claimed in any one of Claims 15 to 25, substantially as described.

Inventors: BAECKER ALBIN ALEXANDER WLADYS, PIZZI ANTONIO, SHELVER GRAHAM DAVID, BAECKER, ALBIN, ALEXANDER, WLADYSLAW, PIZZI, ANTONIO, SHELVER, GRAHAM, DAVID
Applicants: BAECKER ALBIN ALEXANDER WLADYS, BIOTRANS UK LTD, PIZZI ANTONIO, SHELVER GRAHAM DAVID, SILVADUX B V, WOLMAN GMBH DR, BAECKER, ALBIN, ALEXANDER, WLADYSLAW, BIOTRANS UK LTD., DR WOLMAN GMBH, PIZZI, ANTONIO, SHELVER, GRAHAM, DAVID, SILVADUX B.V.
Application year: 1996
Main classification: B27K3
IPC codes: B27K3