AU2011200443A1 - Antisapstain Compositions With Improved Working Properties - Google Patents

Description

25 Subrahmanyam,D. V. and Hocy, G. R. (1975). Effect of Water Quality on the Corrosion and Electrochemical Behavior of Mild Steel in Synthetic Acid Mine Waters. Cortosion 31(6), 202-7. 5 Tadros, A. B. (1988). Inhibition of the Acid Corrosion of Steel by 4-amino-3-hydrazino thio-,2,4-triazoles. J. Electroanat. Chem. 246 433-439. Wahdan, M. H., Gomma, G. K. (1997). Effect of Copper Cation on Electrochemical Behavior of Steel-in Presence of imidazole in Acid Medium. Materials Chemistry and 10 Physics 47(2-3), 176-183.

:1 Regulation 3.2 AUSTRALIA 5 PATENTS ACT, 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT 10 ORIGINAL 15 20 25 30 Name of Applicant: OSMOSE NEW ZEALA ND Actual Inventor: FRAZER, Frank William Address for service in A J PARK, Level 11, 60 Marcus Clarke Street, Canberra ACT Australia: 2601, Australia Invention Title: Antisapstain Compositions With Improved Working Properties The following statement is a foll description of this invention, including the best method of performing it known to LIS. 35 2 TECHNICAL FIELD The invention described herein relates to novel antisapstain compositions, their methods of manufacture and use as antisapstain products, for the protection of timber and other wood substrates against mould, sapstain and decay fungi. 5 BACKGROUND ART Oxine copper fungicidal products were first introduced to the NZ sawmilling industry in the late 1970's for sapstain control. However the products were slow to be adopted by NZ mills because of corrosion concerns. Various early trials at NZ sawmills had shown elevated iron 10 levels in working solutions, indicative of corrosion of mild steel components, and dull grey streaks of iron staining on the wood. Iron stain is as significant as sapstain in the impairment of wood appearance and consequently is a major deterrent for usage of oxine copper products. Additionally, longer term corrosion effects related to maintenance costs and potential downtime of plant and equipment are negative cost factors. 15 Dark coloured solutions are possibly due to the presence of iron quinolinolate compounds, which are black. However it may be noted that working solutions are high in wood extractives and it is possible that other iron coordination compounds contribute to the presence of dark streaks, referred to as iron stain. Experiences of various NZ mills using oxine copper products are that iron levels in 20 working solutions must exceed 100ng/L before iron stain becomes noticeable on the wood. Suppliers of oxine copper products have generally promoted "corrosion control" products based on phosphate compounds (either phosphoric acid or di-sodium hydrogen phosphate) to control iron stain. Although phosphates are known corrosion inhibitors for certain higher pH systems, there is no reported evidence that phosphates reduce corrosion in acidic systems. Timber mill 25 experience shows that the addition of small amounts of phosphoric acid (e.g. 100 mg/L) may reduce iron stain although there is no accompanied reduction of iron levels in working solutions. It would appear that phosphate complex formation is able to keep the iron in soluble form so that iron stain is not evident. Thus phosphate addition produces a masking effect rather than inhibition of corrosion. 30 Addition of phosphates is only partially successful in controlling iron stain and overusage of phosphoric acid may actually accelerate corrosion, and cause a rise in iron levels of the working solution. An akernative approach to corrosion inuimization, practised in the USA, is the neutralisation of oxine copper solutions with borax. This procedure is carried out at the dip bath 35 stage (spray systems are not as common as in NZ) using less than 1% w/v borax and a fine 3 suspension of oxine copper is formed. This approach has not found favour in NZ, with the widely held view that formulations containing particulate oxine copper are not as efficacious as acid solubilised versions. Despite potential corrosion problems outlined above, oxine copper formulations, have 5 proved highly cost efficacious, and have continued to grow in popularity in NZ. From the early 199 0 's the chemical has been the major active used in NZ and many mills, especially those with spray systems, have been able to mitigate corrosion by (epoxy) coating steel surfaces or using stainless steel pumps, spray nozzles etc. Mills with automated dip bath systems, however, have lesser ability to use such corrosive products, as high costs are associated with full protection of 10 plant and equipment, especially for moving plants such as outfeed chains and rollers. In 1992, an emulsifiable concentrate product, Hylite Extra (Chemicca, 1989) containing oxine copper and carbendazim was introduced to NZ sawmills. Hylite Extra is based on solubilisation of oxine copper with dodecyl benzene sulphonic acid (DDBSA) with cosolvents and surfactants suitable to maintain carbendazim solubility in the concentrate. The product has 35 been used by many NZ ills without significant corrosion problems and is therefore a suitable yardstick for development of other potentially corrosive antisapstain products Until the late 1 990's, DDBSA was the only acid used for solubilisation of oxine copper in commercial products. In 1998, oxine copper products based on solubilisation by phosphorous acid were registered in NZ (Maynard, W09953760 (PCT/NZ99/00045)). Cost and efficacy 20 advantages relating to the use of methane sulphonic acid (MSA) have also been revealed (Frazer, W005051618 (PCT /NZ2004/000303)). This patent disclosed that oine copper products based on MSA are less corrosive than equivalent products based on phosphorous acid. However in the development of oxine copper products based on MSA, it is desired to produce products of similar or less corrosiveness to the Flylite Extra product. 25 SUMMARY OF THE INVENTION The present invention is directed to formulations of oxine copper having a quaternary ammonium salt presence that are efficacious (e.g. as antisapstains) and/or which have low corrosiveness of iron for such acid solubilised systems with the copper content. 30 In another aspect the invention is a biocidal composition (whether to be further diluted or not) consisting of at least oxine copper, an acid or acids that at least in part solubilises the oxine copper, and at least one quaternary ammonium salt. 33 Preferably said biocidal composition is an antisapstain composition.

4 A combination of oxine copper and a quaternary ammonium salt in an acid solubilised system for the oxine copper opens up efficacy advantages whether with or without further additions. See, for example, Examples 10-13 hereinafter. The combination, irrespective of whether or not there are such efficacy advantages, provide lower corrosiveness of iron. 5 Preferably said composition has a corrosion inhibiting presence of said at least one quaternary ammonium salt. Optionally said composition in addition includes at least one triazole, preferably a corrosion inhibiting triazole. Preferably said acid or acids is a strong acid or strong acids. 10 Preferably said acid is one or more of MSA (methane sulphonic acid) or phosphorous acid, or a combination of both. Most preferably it is MSA. Preferably said quaternary ammomnum salt is selected from the group consisting of didecyl dimethyl anmonium chloride (DDAC) and benzalkonium chloride (BAC). The preferred acid is MSA. We have also shown the corrosion reduction effect of the 15 quaternary ammonium salt (such as DDAC) with phosphorous acid. These are dissimilar acids. Accordingly we believe that corrosion inhibition by DDAC is unrelated to the acid anion and that the corrosion inhibition provided by the presence of at least a quaternary ammonium salt (such as DDAC or BAC) is applicable to all acids (compatible with the composition components) capable of dissolving oxine copper. Examples of such acids include sulphuric acid, sulphamic 20 acid, nitric acid, phosphoric acid, substituted phosphonic acids and hydrochloric acid. This list may not be exhaustive and mixtures of any of the suitable acids can be contemplated. By way of example of component incompatability, DDBSA has anionic surfactancy properties and is not compatible with DD.AC. Optionally said quaternary ammonium salt itself is a biocide (e.g. a fungicide). 25 Optionally a coactive is present or is added prior to use. Suitable co-actives include one or more triazole, benzimidazole, tri bromo-phenol and/or OPP (ortho-phenyl phenol). However this list is not limiting, and of the several thousand fungicidally active compounds known to mankind, the only formulation requirement is that the co-active be stable in the acidic environments of this invention. 30 Preferably a said optional benzimidazole is carbendazim. Optionally OPP is present. Preferably any optional said triazole is selected from a group typified by benzotriazole, tolyltriazole, tebuconazole and propiconazole.

5 Tebuconazole and propiconazole are corrosion inhibitors. We have shown an additive effect where addition of both QAS (DDAC or BAC) and triazole has produced a lower corrosivity than either corrosion inhibitor individually. Preferably the composition is and/or is to be diluted by a carrier liquid (e.g. water and/or 5 an organic liquid (e.g. a glycol such as ethylene glycol). A preferred organic diluent is a glycol such as ethelyene glycol, however other compatible glycols can be used. Preferably some water is present. In the concentrates as prepared, organic agents such as glycols or non-ionic surfactants may comprise none, part, or all of the carrier fluid. Usually water comprises at least part of the 10 carrier. The composition of the carrier is largely dependent on the solubilisation properties of the co-actives. In the working solutions, by way of example, water comprises over 95 % v/v of the mix. In another aspect the present invention consists in a biocidal composition having oxine copper supported in a system that includes an oxine copper solubilising acid or acids and at least 15 one quaternary ammonium salt sufficient by itself (and with optional additives) to ensure the C, corrosiveness (mg/L Fe) is less than 165. Preferably the C, is less than 136. Preferably the C 1 is less than 100. Preferably the C 1 is less than 80. 20 Preferably the C,, is less than 60. Preferably said C 1 .is less than 50 (more preferably less than 40). Preferably said C,, is less than 30. In still a further aspect the present invention consists in an antisapstain or biocidal composition (whether to be further diluted or not) consisting of at least oxine copper in the 25 presence of an acid or acids that at least in part solubilises the oxne copper, and at least a sufficient presence of a suitahle triazole or suitable triazoics in conjunction with at least one quaternary ammonium salt so as to inhibit corrosion, (e.g. preferably by lowering (as a result of the presence of the triazole(s) and the at least one quaternary arnoniun salt) the C, corrosivity as herein used below than that would otherwise be the case with tle triazole or quaternarV 30 ainmoniurn salt alone). Preferably said acid or acids is a system includes or consists solely of one or both of MSA and phosphorous acid. In another aspect the invention consists in a "two pot" antisapstain composition (whether to be further diluted or not, and irrespective of whether dilution is post or premlxing) 35 comprising or including, 6 (-) as the first "pot": oxmne copper, an acid or acids that at least in part solubilises the oxine copper, and at least one quaternary animonium salt, and 5 (II) as the second "pot": a fungicidal composition. In a further aspect the invention consists in an antisapstain composition inclusive of an oxine copper at least in parr solubilised in an acid or acids, wherein there is a corrosion inhibitory presence of at least one quaternary ammonium salt. 10 Preferably the C, corrosivity is below that of the oxine copper were is solubilised only in MSA. Preferably it is solubilised in MSA and has a C 1 0 below 100 (preferably below 80 more preferably still below 60, 50 or 40 and most preferably below 30). The invention also is an antisapstain composition or biocidal composition 15 comprising or including I to 25% oxine copper, 1 to 70% of oxine copper solubilising acid(s), 1 to 70% of quaternary ammonium salt(s), O to 10"/o of at least one triazole 20 0 to 80% organic carrier(s) 0 to 80% surfactant(s) 0 to 80% water (and optionally other content (e.g. one or more coactive, such as OPP). The % are '/,. Note % "/, x 10 is g/L. 25 In a further aspect the present invention consist in an anflsapstrain composition (e.g. preferably as a concentrate suitable for dilution) comprising or including 1 to 25% oxine copper 0 to 50% MSA 0 to 70% phosphorous acid 30 1 to 70/o a quaternary ammonium salt(s) 0 to 10% of at least one triazole 0 to 80%organic carrier(s) 0 to 80%surfactant 0 to 80% water: 35 and optionally other content (e.g. one or more coactive).

7 wi/b /hepriso that there is a presence of at least one of MSA or phosphorous acid; and wherein the presence of at least the at least one quaternary aromonium salt has a corrosion inhibiting affect. 5 The present invention also includes a "two pot" biocidal or antisapstain composition where addition of one pot to the other provides a composition of any previous aspect of the invention. One pot can include acid(s) and the oxine copper. The other pot can include one or more coactive. Best anticorrosion results from the 10 quaternary ammonium salt(s) and any optional triazole(s) being present whenever the acid solubilised oxine copper is likely to encounter a metal that might corrode. In a further aspect the present invention consists in a method of treating a substrate (preferably wood or timbers) which involves coating and/or impregnating with a composition of any of the kinds of the present invention. 15 In yet a further aspect the present invention consists in a substrate treated by a composition in accordance with the present invention, e.g. treated woods or timbers. In the present invention, quaternary ammonium salts, such as didecyl dimethyl amrnonium chloride (DDAC), may be incorporated in oxine copper formulations, solubilised in strong acids such as MSA or phosphorous acid, to produce antisapstain products of relatively low 20 corrosivirv. Furthermore in the present invention combinations of quaternary ammonium salt plus tiazole. when added to acid oxine copper formulations, have favourable corrosion profiles compared to established commercial oxine copper products. The present invention shows incorporation of quaternary ammomium salts in acidic oimne 25 copper formulations can be used advantageously to produce antisapstain products with enhanced fungicidal activity. Such combinations have nor been previously reported. Examples, not confining of the invention, of how oxine copper plus quaternary ammonium salt combinations may be employed with other actives in a single formulation or combined with suspension concentrate and added as two - pot mixtures to artisapstain 30 application systems are disclosed hereinafter. As used herein the term "and/or" means "and" or "or", or both. As used herein the term "(s)" following a noun includes, as might be appropriate, the singular or plural forms of that noun. As used herein the terry "pot" includes an already mixed component. 35 As used herein the term "Cu8" means or includes oxine copper.

8 Corrosion of Ferrous Metals in Acid Systems Corrosion involves a flow of electrons from the anode to the cathode. In the case of an iron metal anode, the reaction is Fe - 2e 4 Fe 24 and the ferrous ions formed are soluble in the 5 acidic media (pH< 3) of the acid solubilsed oxine copper products of this study. In acidic solutions, two cathodic reactions may occur: (a) Reduction of (dissolved) oxygen: % 02 +2 H 3 0 + 2e 4 3 H 2 0 (b) Reduction of hydrogen (hydronium) ions to hydrogen: 2 H 3 0* + 2e 4 H 2 + 2 OH The reduction of oxygen reaction is relatively independent of pH, whereas the hydrogen 10 evolution reaction is strongly favoured as the pH decreases. A wide range of physical factors, such as temperature, fluid flow rate, physical imperfections and surface area of the metal affect corrosion rates of iron and steel. Chemical factors influencing corrosion rates include the nature of the acid anion, composition of the ferrous metal, and the presence of other anions and cautions. 15 Numerous studies have been carried out on the corrosion protection of ferrous metals in the presence of acids, mainly related to steel pickling compositions. In the 19 *' and early 20 centuries corrosion inhibition additives used for pickling acids, such as hydrochloric acid and sulphuric acid, included flour, molasses, vegetable oils, alkaloids and other plant and animal extracts. 20 The most commonly used corrosion inhibitors used today for iron and steel in acid media are various heterocyclic compounds particularlyy triazoles and inidazolines), quaternary ammonium salts, amine derivatives, organic phosphates, and succinimides (Abdel H-lamid et al, 1998). Heterocyclic compounds are ferrous metal corrosion inhibitors. Use of triazoles to 25 inhibit acid corrosion of steel has been reported by Al-Farkh (1980); Tadros (1988); Muralidharan (1995); Bentiss et al, (1999); Green (1998); Kravitz (2003), and Chebabe etal, (2003). Use of oxadiazoles is reported by Bentiss, (2003) and thiazole compounds by Athar, (2002). Cationic surfactants, particularly quaternary ammonium salts, have been shown to be efficient corrosion inhibitors for acid solutions in contact with ferrous metals (-Abdel Hanmid et al, 30 1998; fEl Dahan et at 1999). Bereket and Yurt, (2002) in a study of none cationic surfactants, including six quaternary ammonium salts, concluded that inhibition efficiency increased with Increasing chain length of the hydrophobic group and the presence of an aromatic group.

9 Corrosion of Ferrous Metals in Acid Systems which Contain Copper Ions The presence of copper ions in acid systems presents a further complexity due to the presence of a third competing cathodic reaction, related to the reduction of copper ions to copper metal: 5 Cu 2 + 2e -> Cu The presence of copper ions in acid solutions has been shown to enhance corrosion of steel (Subrahmanyam and Hoey, 1975: Scheers, 1992). However, Singli and Singh, (1987) report that ppm quantities of copper ions reduce the corrosion rate of mild steel in sulphuric acid. Also a Japanese patent (Hatsutori et al, 1995) relates to addition of copper ions to reduce corrosion of 10 stainless steels in contact with organic sulphonic acids. Corrosion of steel may be enhanced or reduced by copper ions in conjunction with corrosion inhibitors. Wahden et al (1997) report that 10 4 M quantities of copper in conjunction with imidazole strongly inhibited corrosion of steel by sulphuric acid- However higher copper ion concentrations (10-' 4) caused an increase of corrosion rate. Gomaa (1998) reports corrosion 15 of steel in 0.1M4 sulphuric acid is significantly reduced by a combination of benzotriazole and 10 M copper ions. At higher copper ions concentrations corrosion rates are enhanced. The use of heterocyclic compounds to reduce corrosion of steel in the presence of copper ions has been reported by Gomaa, (2000), who studied the effect of copper ion concentration on the corrosion of steel by sulphuric acid in the presence of tolyltriazole. The inhibition efficiency of tolyltriazole 20 was greater with increasing copper ion concentrations in the range 10' to 10- M4. Measurement of Corrosion The two main laboratory corrosion methods used in the above referenced studies are potentiodynamic methods and coupon corrosion tests. 25 Apparatus for potendodynamic methods comprises a three electrode system with a polished mlid steel anode, a platinum counter electrode and a saturated calomel reference electrode. The method, described for example by Neufeld, (1989), involves initial immersion of the iron electrode to measure the free corrosion potential before the polarization curves are recorded. The cathodic polarization measurements are yielded by constantly scanning to higher 30 negative potentials and recording the resultant corrosion currents. Similarly anodic measurements may be recorded by moving to higher positive potentials. Inhibition efficiencies are determined from corrosion currents by the Tafel extrapolation method. Measurements are repeated for different concentrations of the corrosion inhibitor and the resulting changes in Tafel slopes in the cathodic and anodic regions ae indicative of whether the inhibitor affects 35 predominantly the cathodic or anodic reaction.

10 Ahemiatively, corrosion rates may be determined by weight loss measurements of immersed test specimens (coupons) of known composition for various periods in the corrosive solutions. Prior to immersion, the coupons should be polished to remove oxide and cleaned to remove any surface contamination. After immersion the coupons are carefully removed, dried 5 and weighed. Although these methods have found widespread application in measuring corrosion of steel in acid media, we have discovered difficulties in obtaining meaningful results in our antisapstain product systems containing copper ions. Problems may be caused by copper plating on the steel surface, which in some cases forms a dense tenacious coating on the steel surface 10 which inhibits further corrosion. In other cases copper is formed with little affinity to the steel and is easily flaked off to form a fresh steel surface for continued corrosion- In the potentiodynamic method, described above, it is essential to have a constant anode surface to make meaningful measurements of corrosion currents. Also in coupon corrosion tests the effect of copper plating on the steel surface causes a weight gain, rather than a weight loss. 15 This invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, and any or all combinations of any two or more of said parts, elements or features, and where specific integers are mentioned herein which have known equivalents in the art to which this invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth. 20 BRIEF DESCRIPTION OF DRAWINGS A preferred form of the present invention will now be described with reference to the accompany non limited examples and drawings in which Figure 1 is a plot in respect of Example 6 of Fe (mg/L) against Time evaluating 25 Tolyltriazole and DDA (as Corrosion Inhibitors, and Figure 2 is a plot in respect of Example 7 of Fe (mg/li) against Time evaluating Tebuconazole and Propiconazole as Additives. DETAILED DESCRIPTION 30 In recognition of the difficulties of corrosion testing acidic copper solutions we developed a corrosion test method based primarily on the reactivity of iron in the corrosive solution, without the major influence of copper plating. In our method a measured weight of cast iron filings is added to a stirred volume of the test solution. At specified time intervals, aliquots of the test solution are removed and 11 immediately filtered to remove any iron filings, the filtrate being retained for analysis of iron. The iron content of the filtrate is recorded as a measure of the corrosiveness of the test solution. The apparatus consisted of a variable speed stirrer (rotation speed 4 0 0 rpm) fitted with a Quickfit glass stirrer shaft and matching 40mm segment blade. The apparatus settings were 5 designed to allow some movement of the iron particles in the stirred solution but the fluid movement was not sufficient to create a large vortex and thus create major air entrapment in the fluid. A selected iron filings fraction of particle size of -355 + 106 microns was used for the corrosion studies. Using 5OmL of the test solution in the beaker and with the stirrer turned on, 1.00g of 10 cast iron filings is added to the solution. At time periods 2, 4, 8, 12, and 16 minutes, 10 mL aliquots were removed from the solution and immediately filtered to remove any iron particles. Filtrates were retained for iron analysis by atomic absorption spectroscopy. The relationships between solute iron contents and reaction times may he presented graphically- For comparisons between samples it has been found convenient to have a single 15 measure of corrosivity. In this study the iron content at 10 minutes reaction time was chosen (denoted as C 10 ), interpolated from the best (polynomial) fit to the graph. Repeatability tests indicated a standard deviation of 7% around a mean value for a single point of time analysis, which is satisfactory for our range of corrosivities encountered. The main advantage of this corrosion method is that the presence of a large surface area 20 of highly reactive iron mminimises the copper plating inhibition effect and thus is a better reflection of the reactivity of the metal surface to che corroding solution. It may be argued that copper plating of steel surfaces is also seen in the industrial environment and so this effect should also be an integral part of the laboratory method. However it should be noted in relation to industrial plant and equipment, that the tenacity of the copper coating depends on a number of 25 physical factors (cavities, local flow rates, weld defects, etc) not necessarily represented by the polished steel surfaces of the laboratory specimens. The development of experimental method for determining corrosion as detailed above has permitted an understanding of the nature of corrosion of the various oxine copper based antisapstain products of interest. Fundamental to understanding these systems is knowledge of 30 whether corrosion was essentially due to the acid nature of these systems or due to the presence of copper ions in solution. In the former case, where corrosion is dependent on the reduction of hydrogen ions (hydrogen evolution reaction), previous research by other workers into corrosion inhibition of the hydrogen evolution reaction, discussed above, may also be applicable to our antisapstain systems. Alteratively if the corrosion was related mainly to the cathodic reduction 35 of copper ions to copper, it would be apparent that there would be little useful existing 12 information available as corrosion inhibition of similar systems have not been widely studied. In fact, timber treatments may be the only commercial applications of acid systems containing appreciable concentrations of copper ions, where corrosion is of major importance. Although it is visually apparent that copper plating occurs on steel surfaces in contact 5 with antisapstain solutions it is not obvious if the copper reaction is a minor or major contributor to the total corrosion. Therefore the first two examples have been designed to quantify the relative contributions of the various competing cathodic reactions. Example 1. Corrosion Properties of Oxine Copper Products Solubilised by Various Acids. Six products were prepared as aqueous concentrates with the following ratios (w/w) of 10 acid to oxine copper; DDBSA 10.7:1 Phosphorous acid = 4.8:1 MSA 1.75:1 Sulphuric acid 2.0: 1 15 Phosphoric acid = 6.75:1 Suiphamic acid 2.7:1 Each of the above solutions, diluted to a concentration of lg/L oxine copper was tested by the above cast iron filings corrosion test. The C, corrosivities (Fe solubilised after 10 minutes 20 reaction) and pH of the solutions were measured. As shown in Table 1, similar corrosivities were observed for sulphuric, sulpharmic, phosphorous and phosphoric acids. The DDBSA formulation had a significantly lower corrosivity and MSA appeared to have intermediate corrosivity. It was considered possible that differences in corrosivity may be related to the hydrogen ion contents of the solutions. Therefore 25 comparative pH measurements were made on the six formulations, also shown in Table t Tablet Comparison of Corrosivity and pH for Acid Solubilised Oxine Copper Products. Sample Cu-8 (g/L) Acid Acid (g/L) pH Ci (Fe mg/L) 500 1.0 Phosphorous 4.8 1.67 165 504 1.0 DDBSA 10.7 1.94 58 650 1.0 MSA 1.75 1.81 136 523 1.0 Sulphuric 2.0 1.80 175 525 1.0 SuIphamic 2.7 1.81 178 527 1.0 Phosphoric 6.7 1.89 175 13 Although the DDBSA formulation had the lowest corrosivity and che highest pH, there was no obvious relationship between pH and corrosivity for the samples. 5 Example 2. Comparison of Acid Corrosivities in the Absence of Oxine Copper Aqueous formulations of the six acids were prepared to give the same acid concentrations used in the test solutions of Example 1. and tested for corrosivirv by the same procedure as in Example 1. Comparisons of the C, corrosivities of the acid onk and the acid + oxine copper 10 products are shown in Table 2. Table 2. C 1 Corrosivities of Various Acids with and without Oxine Copper.

C

10 (mg/L Fe) Acid only Acid + Oxine Copper Phosphorous Acid 55 165 DDBSA 29 58 Sulphuric Acid 46 175 Sulphamic Acid 52 178 Phosphoric Acid 66 175 Methane Suiphonic Acid 43 136 The results showed that the presence of oxine copper greatly enhanced the degree of 15 corrosion. Thus the major cathodic reaction occurrig was the reduction of cupric ions, rather than reduction of hydrogen ions which accounted for about one-hird of the total corrosion. This data confirms that the corrosivities of antisapstain solutions of this invention are due mainly to the reduction of cupric ions. Therefore in the search for suitable corrosion inhibitors for these products, no reliance can be made on corrosion inhibitors designed for systems which 20 do not contain copper ions. Example 3. Evaluation of Carbendazim and Oxinate Anion as Corrosion Inhibitors The search for corrosion inhibitors for oine copper formulations was prompted by our previous discovery (Frazer, 2004) that methane sulphonic acid (MSA) afforded a cost effective 14 means of formulating such products. Although the corrosivity of MSA formulations was less than equivalent products formulated with phosphorous acid they were higher than products formulated with DDBSA, such as Hvlte Extra- Therefore the objective was to locate an additive to the MSA formulations that would exhibit similarly low corrosion characteristics to 5 formulations based on DDBSA. Early studies related to determining if any of the components of oxine copper formulations such as carbendazim or the oxinate anion provided any corrosion inhibition, Therefore oxine copper formulations (based on MSA) with and without carbendazim were compared. The differences between the corrosivities of a solution without carbendazirn (C 1 136) and with lg/L carbendazin (C, = 115) were minor and almost within experimental error. 10 Also small differences were observed between MSA foirnulations containing oxine copper (C 1 0 136) and copper hydroxide (C, = 161) indicating that the presence of the oxinate ion may have a weakly inhibitive effect on corrosion. Example 4. Evaluation of DDAC as a Corrosion Inhibitor 15 Background Preliminary visual assessments of rild steel coupons inmnersed in an oxine copper solution (MSA chased) indicated that the quaternary aimnonium salts (QAS). may have corrosion inhibitory properties. 20 As reported above, quaternary ammonium salts are known corrosion inhibitors in acid systems. However, DDAC does not have been specifically studied in this regard- In addition, the ability of quaternary arnmonium salts to inhibit corrosion in acid systems containing copper ions has nor previously been reported. Five oxine copper formulations were prepared containing lg/L oxine copper, 2.5g/L 25 MSA and levels of DDA C ranging from zero to 21.4g/L (note - all DIDAC contents are expressed as 100% active. Corrosive properties of the fortnulations were tested by the cast iron filings method. Oxine copper samples based on DDBSA (10.7g/L) and Hvlite Extra were included in the comparison shown in Table 3. The corrosion rates for all the samples containing DDAC were similar, and significantly 30 less than the sample containing no DDAC. The results clearly showed that DDAC is a corrosion inhibitor for this system. The corrosion rates of the DDAC containing samples were similar to the oxine copper product formulated with DDBSA (sample 504), but higher than the commercial product, Iylite Extra (sample 506). 35 15 Table 3. Compositions and Corrosivities of Samples Containing DDAC. COMPOSITION

C

10 (g/L) mg/L 5 Sample Cu--S MSA DDAC 533 1.0 2.5 nil 180 10 538 1.0 2.5 0.6 53 537 1.0 2.5 2.3 53 536 1.0 2,5 5.4 51 535 1.0 2.5 21.4 56 15 504 1.0 DDBSA 10.7g/L 58 506 1.0 Hylite Extra 21 20 Example 5. Evaluation of Benzotriazole as a Corrosion Inhibitor. DDAC has corrosion inhibitory properties in oxine copper formulations. However, none of the DDAC containing formulations matched the desired low corrosion rates obtained for Hylite Extra. A further chemical that showed promise in a visual pre-screening trial was 25 benzotriazole. An oxine copper/ Carbendazim/ MSA test solution was prepared. The corrosive properties of this base solution were compared to three equal solutions, which contained either DDAC or benzotriazole. The compositions of these solutions are shown in Table 4.

16 Table 4. Composition of Samples to Determine Corrosion Inhibitory Effects of Benzotriazole. Oxine C10 Carbendazim MSA DDAC Benzotriazole Sample Copper Corrosivity g/L g/L g1L g/L g/L Fe (ppm) 661 1.0 1.0 3.5 - 107 662 1.0 1.0 3.5 64 - 40 663 1.0 1.0 3.5 - 0.4 23 664 1.0 1.0 3.5 - 0.8 23 Hylite Extra 1.0 1.0 Proprietary (DDBSA based) 21 5 The resuls showed that additions of benzotriazole at 0.4 and 0.8g/L produced cortositon inhibitory effects significantly greater than addition of 6.4g/L DDAC. No greater benefit is achieved at O8g/L compared to 0.4g/L benzotriazole. Corrosion rates for the benzotriazole containing samples were similar possiblev slightly higher) to the sample of Hvite Extra. 10 Example 6. Evaluation of Tolyltriazole as a Corrosion Inhibitor. A sample containing 75g/L oxine copper, 280g/L MSA (100% equivalent) and 200g/L DDAC (100% equivalent)f and 30g/L tolyltriazole was prepared (sample 724), which was stable at ambient temperature - A further sample without the tolituiazole was also prepared for comparison (sample 726). Solutions for the cast iron filings corrosion test were prepared by 15 dilution of the concentrates to oxme copper concentrations of lg/L Comparison of the corrosion rates of the oxine copper/MSA samples with DDAC only and DDAC plus tolyhltriazole (Fig.1) showed that tolyltriazole was ar effective corrosion inhibitor for this system. The corrosion rate of the tolyltriazole containing sample was comparable to Hvlite Extra. 201 17 Example 7. Evaluation of Tebuconazole and Propiconazole as Corrosion Inhibitors. The triazole compounds, tebuconazole and propiconazole have known fungicidal properties and have use as wood preservatives, although the generally high costs of these 5 compounds have precluded use in antisapstain products. However these compounds may be used at low levels to mitigate corrosion of oxine copper formulations as shown in this example. Formulations 726, 729, and 730, containing DDAC and tebuconazole or propiconazole were prepared as shown in Table 5. 10 Table 5. Compositions of Solutions Containing DDAC, and Triazoles. Oxine Cu MSA DDAC (as 100%) Other Sample g/L g/L g/L (g/L) 726 1.0 2.8 2.0 729 1.0 2.8 2.0 Tebuconazole (0.4) 730 1.0 2.8 2.0 Propiconazole (0.4) Hylite Extra 1.0 Carbendazim (1.0) Results from the cast iron filings corrosion test are shown in Figure 2. The two triazole compounds (propiconazole and tebuconazole) showed good corrosion inhibition and the formulations were comparable to H-ylite Extra in this regard. 15 Example 8. Evaluation of Benzalkonium Chloride as a Corrosion Inhibitor. Previous examples show the corrosion inhibition properties of DDAC in acid oxine copper systems. The ability of other quaternary aimonium salts, such as alkyl (C12-16) dimethyl benrzyl ammonium chloride, commonly referred to as benzalkonium chloride (BAC). is 20 demonstrated in this example. Aqueous solutions prepared by dissolving copper oxide in MSA at 70"C and adding quantities of BAC and/or tolyltriazole to the cooled solutions. The working solution concentrations and the C10 corrosivities of the tested solutions are shown in Table 6.

is Table 6. Compositions and Corrosivities of Formulations Containing BAC and Tolyltriazole. Cu2+ MSA SAC as 100% Tolyltriazole C10 corrosivity Sample (g/L) (g/L) (g/L) (g/L) (g/L) 720 0.18 2.2 186 721 0.18 2.2 - 0<57 24 722 0.18 3.2 1.76 0.53 19 723 0.18 3.0 1.75 - 40 5 Comparison of the corrosivities of samples 720 and 723, shows that the quaternary ammonium salt, BAC, is also effective corrosion inhibitor. This indicates that the inhibition is related to the functional moiety of the quaternary ammonium ion rather than the hydrocarbon groups, and that all quaternary amrmonium compounds will therefore exhibit corrosion inhibitive properties. The sample containing tolyltriazole (721) showed a greater inhibitory effect compared 10 to the sample containing BAC. However as shown in Examples 6 and 7, the quaternary amrnonium salt may be advantageously combined with a triazole to produce lower corrosivity than either inhibitor alone. Example 9. Corrosion Inhibitive Properties of QAS in Other Acid Systems. 15 Alternative acid systems used to commercially to solublise oxine copper include DDBSA and phosphorous acid. The sulphonic acid, DDBSA, has anionic surfactancy properties whereas quaternary amrnonium salts are cationic surfactants. Although it is possible to combine anionic and surfactant surfactants in Formulations there is a net cancelling of the activities of the individual compounds and upon dilution with water in working solutions highly insoluble 20 compounds are formed. We have therefore not applied this corrosion inhibition technology to oxine compound formulations based on DDBSA. Iowevcr this technology may be usefully applied to inhibit corrosion in oxine copper formulations based on strong acids, such as phosphorous acid as shown in this example, as follows: 25 Sample (A) - 1 Og of oxine copper were dissolved in 48 g Phosphorous acid 65.5 g Water.

19 Sample (1) - To 6.1 7 g of Sample (A) , 4117 g of 80% DDAC was added to produce a clear solution. Both products (A) and (B) were diluted with water to equivalent 1g/L as oxine copper and tested for corrosivity by the cast iron fihngs test method. The compositions and corrosivities 5 of the test solutions are shown in Table 7. Table 7. QAS as Corrosion Inhibitor for Oxine Copper in Phosphorous Acid. Oxine Copper Phosphorous Acid DDAC Corrosivity Sample g/L g/L g/L (ppm Fe) 500 1.0 4.8 - 164 531 1.0 4.8 5.5 56 The results indicate that the levels of inhibition provided by DDAC in phosphorous acid 10 systems are similar to that provided in the MSA system described in Example 4. Example 10. Efficacy of two Oxine Copper Products Containing QAS. Two oxine copper products containing DDAC were prepared as concentrates as per Table 8. 15 Table 8. Compositions of Concentrates containing Oxine Copper and DDAC. Sample 395 Sample 431 (%w/w) (%w/w) Oxine Copper 4.3 4.5 MSA (as 100%) 8.7 11.6 DDAC (as 80%) 10.9 23.6 Ethylene glycol 70.6 Water - 60.3 Tribromophenol 5.4 - 20 Both these products were trialled at 2% v/v. The reference sample of Hylite Extra was trialled at a dilution of 1.2% v/v. Timber lengths of 100 x 25mm were taken from a sawmill green chain (prior to antisapstain treatment) and pieces were selected containing high sapwood contents- The timber 5 was cut to 400 mm lengths and pieces containing significant wane or defects were rejected. The pieces were stacked in piles to allow some degree of randomness of wood selection for the individual wood treatments. Individual pieces were dipped for 10 seconds in a plastic tub containing the various treatment solutions. After dipping, the boards were rested in a near vertical position until drip 10 free. The boards were then transferred to a warm room at 24"C and 50% RH, individually placed on their sides on shelves to partially air dry for three days before placing in plastic bags and sealed for storage. Each treatment comprised 30 boards arranged in a packet 10 high by three wide. Inspection of the treated timber was made after nine weeks storage of average infection (two faces) per board. A fass / fail criterion was used whereby a failed surface is defined as 15 having greater than 5% fungal coverage of the board surface area. The trial results expressed as % failed surfaces were as follows: Sample 395 (Oxine Cu + DDAC + Tribromopheno:) = 11% Sample 431 (Oxine Cu + DDAC) 2% Hvlite Extra = 65% 20 Sample 431, containing oxine copper and the higher level of DDAC, performed significantly better than Hylite Extra, which contained similar levels of oxine copper in the trial treatments. Sample 395, containing the co-active tribromophenol performed better than Hylite Extra, but not as well as sample 431, which had a higher DDA C content. 25 Example 11. Use of Oxine Copper/QAS Formulations with Other Fungicides (Two-Pot Mixtures). Composition 784 was prepared with the following components (%w/v); Oxine copper (7.5); DDAC (20); Tolyltriazole (1.5); MSA (28); Non-ionic surfactant (4.5); 30 Ethylene glycol (17.5); Water (46.5). Composition 784 was diluted to 2% (v/v) for efficacy evaluation by the same procedure outlined in Example 10. A second 2% dilution of composition 784 was prepared and 0.8% (viv) of a 50% suspension of chlorothalonil was added directly to the working solution while stirring to ensure a uniform suspension. A third preparation of 2% (v/v) of Hylite Extra was used as a 21 reference control to assess the comparative efficacies of the compositions. The trial results expressed as % failed surfaces after 13 weeks were as follows; 2% Composition 784 (Oxine copper + DDAC) 17% fails Above composition + 0.4% chlorothalonil 3% fails 5 2% Hylite Extra 45% fails The results show potentially high fungicidal efficacy is achievable from such two pot mixtures. Example 12. Incorporation of a Third Active in Oxine Copper/QAS formulations. 10 In some cases it may be advantageous to incorporate additional fungicides into formulations of oxine copper and QAS. For instance, to improve resistance to mould fungi, the fungicide ortho-phenyl phenol (OPP) may be employed as per the Composition 785 as follows; Composition 785 (%w/v); Oxine copper (7.5); DDAC (36.8); OPP (7.5); NSA (28); tolyltriazole (1.5); Nonionic 15 surfactant (6); Water (31). Composition 785 was diluted to 2% (v/v) for efficacy evaluation by the same procedure outlined in Example 10. Comparative evaluations with a similar composition without OPP and Hylite Extra were made after 13 weeks storage as follows; 2% Composition 785 (oxine copper + DDAC + OPP) 5% fails 20 2% Composition 784 (oxine copper + DDAC) 17% fails 2,u Hylite Extra = 45% fails The result showed that the incorporation of OPP into the formulation improved fungicidal efficacy of the oxine copper/DDAC combination. 25 Example 13. Further Example of the Efficacy Contribution of DDAC. Composition 785 in Example 12, which contained oxine copper, DDAC and OPP was compared-to two similar formulations with adjusted DDAC levels to determine the contribution of DDAC in the formulation. 30 The concentrations of the working solutions, in which the test pieces of wood were dipped are shown in Table 9. The test method used was similar to that described in Example 10. However the wood showed some signs of pre-infection which was reflected in the relatively high infection levels of all treatraents in the trial.

22 Table 9. Efficacy of Oxine Copper Compositions with Varying DDAC levels Oxine DDAC OPP Tolyltriazole % Fails Sample copper (g/L) (g/L) (gIL) (g/L) (9 weeks) 797 1.5 0 1.5 0.3 36 796 1.5 4.0 1.5 0.3 19 785 1.5 7.36 1.5 0.3 10 Hylite Extra 1.5 1.5 g/L Carbendazim 83 The results confirmed the importance of the quaternary ammonium salt in the 5 fornulations with increased efficacy related to higher levels of DDAC.

23 REFERENCES Abdel Hamid, Z., Soro, T. Y., El Dahan, H. A. and Omar, A. M. A.(1998) New Cationic Surtactant as Corrosion Inhibitor for Mild steel in Hydrochloric Acid Solutions. 5 Anticorrosion Methods and Materials 45, 306-311. AI-Farkh, Y., Alhajjar, F.H., Hamoud, H.S. and Al-Shamali, F.S (1980). Further Experiments on the Control of Cornosion ofMild Steel in Crude Oil Distillation. Corrosion Science 20, 1195-1200. 10 Athar, M. and Quraishi, M.A. (2002). Corrosion Inhibition of Carbon Steelin Hydrochloric Acid by Organic Compounds. British Corrosion Journal 37, 155-158. Bentiss, F., Lagrenee, M., Traisnel, M. and Hornez, J. C. (1999). The Corrosion 15 Inhibition of Mild Steel in Acidic Media by a new Triazole Derivative. Corrosion Science 41 789-803. Bentiss, F., Traisnel, M., Vesin, H. and Lagrenee, M. (2003) Linear resistance model of the inhibition mechanism of steel in HCi by triazole and oxadiazole derivatives: structure 20 activity relationships. Corros ion Science 45 371-3 80. Bereket, G. and Yurt, A (2002). Inhibition of the Corrosion of Low Carbon Steelin Acidic Solution by Selected Quaternay Ammonium Compounds. Anti Corrosion Methods and Materials 49, 210-220. 25 Chebabe, D., Ait Chikb, Z., Hajjaji, N., Srhihi, A. and Zucchi,F. (2003). Corrosion Inhibition ofArmco Iron in I M HCL Solution bv Alkvtriazoles. Corrosion Science 45, 309-320. 30 Chemicca Ltd (1989). Improvements in or Relating to Fungicides. NZ Patent 225428. El Dahan, H. A., Mohamed, T. Y. S. and Abo El-Enin, S. A. (1999). Efficient Quaternary Ammonium Salt as Corrosion Inhibitor for Steel Pick/ng in Sulphuric Acid Media. Anti Corrosion Methods and Materials 46, 358-363. 35 24 Gomaa, G. K. (1998). Influence of Copper Cation on Inhibition of Corrosion for Steelin Presence of Benzorriazole in SuffuricAcid Materials Chemistry and Physics 55(2), 131 138. 5 Gomaa, G. K. (2000). Effect of Copper Cation on Corrosion of Steel by Tolyltriazole in Acidic Medium. Indian Journal of Chemical Technology 7, 300-306. Green, B. P. (1998) A Biocidal Corrosion Inhibiting Compound. Int. Patent W098/22554. 10 Hatsutori, A., Nakamura, K., Noda, T. and Washama, T. (1995). Corrosion Prevention with Copper Ions for Stainless Steel in Handling of Organic Sulfonic Acids. Jpn. Kokai Tokkyo Koho. Application: JP 94-68530. Kravitz, J.I. (2003). AntimicrobialLubricant Coating and Method for Using. U.S Pat. 15 6,525,005. Maynard, N. P. (1999). A Biocidal Composition Containing Phosphite Ions. International Patent, WO 9953760. 20 Muralidharan, S., Quraishi, M.A. and Iyer,S.V.K. (1995). The Effect of Molecular Structure on Hydrogen Permeation and the Corrosion Inhibition of Mild Steel in Acidic Solutions. Corrosion Science 37 1739-1750. Neufeld, P.(Ed.) 1989. A working Party Report on Practical Corrosion Principles. 25 European Federation of Corrosion Publications No 2, Institute of Metals, London. Scheers, P. V. (1992). The Effects of Flow Velocity and pH on the Corrosion Rate of Mild Steel in a Synthetic Minewater. Journal of the South African Institute of Mining & Metallurgy. 92(10), 275-81. 30 Singh, I. and Singh, M. (1987). Effect of Metallic Cations on the Corrosion and the Hydrogen Absorption by Cold-rolled Mild Steel in Inhibited Sulfuric Acid Corrosion 43(7),425-9.

Claims (52)

1. A combination of oxine copper and a quaternary ammoniurn salt in an acid solubilised system for the oxine copper.

2. A biocidal composition (whether to be further diluted or not) consisting of at least: 5 oxine copper, an acid or acids that at least in part solubilises the oxine copper, and at least one quaternary ammonium salt.

3. A composition of claim 2 which is an antisapstain composition.

4. A composition of claim 2 or 3 wherein the quaternary ammonium salt presence is a 10 corrosion inhibiting presence of said at least one quaternary ammonium salt.

5. A composition of any one of claims 2 to 5 xvherein said acid or acids is a strong acid or are strong acids.

6. A composition of claim 5 wherein said acid is MSA (methane sulphonic acid), phosphorous acid, or both. 15

7. A composition of claim 5 wherein the acid is MSA.

8. A composition of any one of claims 2 to 7 wherein said at least one quaternary ammonium salt is selected from the group consisting of didecyl ditnethyl ammonium chloride (DDAC) and benzalkonium chloride (BAC).

9. A composition of any one of claims 2 to 8 wherein said at least one quaternary 20 amrnonium salt itself is a biocide.

10. A composition of any one of claims 2 to 9 wherein a coactive is present or is added prior to use.

11. A composition of claim 10 wherein said coa c tive is at least one of the group comprising benAmidazoles and OPF (ortho-phenyl phenol). 5

12. A composition of claim 11 wherein O1P is present.

13. A composition of any one of claims 2 to 12 having, in addition, at least one triazole.

14. A composition of claim 13 wherein said triazole is a corrosion inhibiting riazole.

15. A composition of claim 13 or 14 wherein said triazole is selected from a group typified by benzotriazole, totyltriazolc, tebuconazole and propiconazole. 30

16. A composition of claim 15 wherein at least one of tebuconazole and propiconazole is present.

17. A composition of any one of claims 2 to 16 wherein there is present (a) DDAC, BAC, or both, and (b) a triazole.

18. A composition of any one of claims 2 to 17 diluted or to be dilu ted by a carrier liquid. 35

19. A composition of claim 18 wherein said carrier liquid is or includes water. 27

20. A composition of claim 18 or 19 wherein said carrier liquid is a glycol with or without a water presence.

21. A composition of any one of claims 18 to 20 wherein it has been diluted and water comprises over 95% v/v of the diluted composition. 5

22. A biocidal composition having oxine copper supported in a system that includes an oxine copper solubilising acid or acids and at least one quaternary ammonium salt sufficient by itself (and with optional additives) to ensure the C, corrosiveness (ng/L Fe) is less than 165.

23. A biocidal composition of claims 22 wherein the C, is less than 136.

24. A biocidal composition of claim 23 wherein the C, is less than 100. 10

25. A biocidal composition of claim 24 wherein the C,is less than 80.

26. A biocidal composition of claim 25 wherein the C, is less than 60.

27. A biocidal composition of claim 26 wherein said C,.is less than 50

28. A biocidal composition of claim 27 wherein said C,.is less than 40.

29. A biocidal composition of claim 28 wherein said C, is less than 30. 15

30. An antisapstain or biocidal composition (whether to be further diluted or not) consisting of at least oxine copper in the presence of an acid or acids that at least in part solubilises the oxine copper, and at least a sufficient presence of a suitable triazole or suitable triazoles in conjunction with at least one quaternary ammonium salt so as to inhibit corrosion, (e.g. preferably by lowering (as a result of the presence of the triazole(s) and the at least one 20 quaternary ammonium salt) the C, corrosivity as herein used below than that would otherwise be the case with the triazole or quaternary ammonium salt alone).

31. An antisapstain or biocidal composition of claim 30 wherein said acid or acids is a system includes or consists solely of one or both of MSA and phosphorous acid.

32. A "two pot" antisapstain composition (whether to be further diluted or not, and 25 irrespective of whether dilution is post or premixing) comprising or including, as the first "pot": oxme copper, an acid or acids that at least in part solubilises the oxine copper, and at least one quaternary ammonium salt, and 30 (II) as the second "pot": a fungicidal composition.

33. An antisapstain composition inclusive of an oxine copper at least in part solubilised in an acid or acids, wherein there is a corrosion inhibitory presence of at least one quaternary ammonium salt. 28

34. An antisapstain composition of any one of claims 30 to 33 wherein the C, corrosivity is below that of the oxine copper were is solubilised only in MSA.

35. An antisapstain composition of claim 34 wherein it is solubilised in MSA.

36. An antisapstain composition of claim 35 wherein it has a C, below 100. 5

37. An antisapstain composition of claim 36 wherein it has a Cm.below 80.

38. An antisapstain composition of claim 37 wherein it has a Cm.below 60.

39. An antisapstain composition of claim 38 wherein the C,.is below 50.

40. An antisapstain composition of claim 39 wherein the C 1 ,.is below40.

41. An antisapstain composition of claim 40 wherein the C k.is below 30. 10

42. An antisapstain composition or biocidal composition comprising or including 1 to 25% oxine copper, 1 to 70% of oxine copper solubilising acid(s), 1 to 70% of quaternary ammonium salt(s), 0 to 10% of at least one triazole, 15 0 to 80% organic carrier(s), 0 to 80% surfactant(s), and 0 to 80% water, and, optionally, other content.

43. An antisapstain composition or biocidal composition of claim 42 wherein at least one 20 coactive selected from the benzimidazoles or OTP is/are present.

44. An antisapstrain composition whether as a concentrate suitable for dilution or otherwise, the composition comprising or including 1 to 2 5 % oxine copper, 0 to 50% MSA, 25 0 to 70% phosphorous acid, 1 to 70% a quaternary ammonium salt(s), 0 to 10% of at least one triazole, 0 to 80%organic carrier(s), 0 to 80%surfactant, and 30 0 to 80% water; and, optionally, other content wherein that there is a presence of at least one of MSA and phosphorous acid; and wherein the presence of at least the at least one quaternary ammonium salt has a corrosion inhibiting affect. 29

45. An antisapstain composition of claim 44 wherein one or more coactive selected from the benzimidazoles and OPP is/are present.

46. A "two pot" biocidal or antisapstain composition where addition of one pot to the other provides a composition of any one of claims 2 to 31 and 33 to 45. 5

47. A "two pot" biocidal or antisapstain composition of claim 46 wherein one pot includes acid(s) and the oxine copper.

48. A "two pot" biocidal or antisapstain composition of claim 47 wherein the other pot includes one or more coactive.

49. A "two pot" biocidal or antisapstain composition of any one of claims 46 to 48 wherein 10 triazole at least one triazole is present.

50. A method of treating a substrate which involves coating and/or impregnating with a composition of any one of claims 2 to 49.

51. A substrate treated by a composition in accordance with any one of claims 2 to 49.

52. A substrate of claim 51 which is a wood or timber. 15