Method and formulation for the treatment of timber

Abstract

According to the present invention there is provided a method of treating timber with a creosote-containing preservative formulation adapted for use at substantially ambient temperature. The formulation comprises: creosote; one or more surfactants such that when diluted with a predetermined quantity of water, the creosote is present as an oil-in-water macroemulsion or microemulsion; and optionally, an anti-foaming agent and/or a fire retardant. It is found empirically that the inventive concentrate allows for the use of creosote, a known-effective biocide, without many of the drawbacks inherent in such use.

Claims

1. A method of treating timber, the method comprising the steps of: selecting a timber substrate; and applying to the substrate an effective amount of a diluted preservative formulation concentrate comprising an oil-in-water macroemulsion or microemulsion of creosote in water, wherein the preservative formulation concentrate comprises creosote and at least two surfactants, a non-ionic surfactant and an anionic surfactant, wherein the non-ionic surfactant is ethoxylated castor oil, wherein the anionic surfactant comprises a calcium alkylbenzene sulfonate wherein the non-ionic surfactant is present in concentrate in an amount of from 1% to about 20% w/w, wherein the creosote is present in the concentrate in an amount of about 70% to about 95% w/w; and wherein the preservative formulation is at substantially ambient temperature.

2. A method according to claim 1, wherein the substantially ambient temperature is between about 5 C. and about 60 C.

3. A method according to claim 1, wherein the substantially ambient temperature is between about 17.5 C. to about 25 C.

4. A method according to claim 1, wherein the step of applying the preservative formulation, which is at substantially ambient temperature, is performed by means of dipping, brushing, spraying, misting, deluging or coating the surface area of the timber with the preservative formulation.

5. A method according to claim 1, wherein the timber comprises hardwood and/or softwood species.

6. A method according to claim 1, wherein the timber is pine posts and wherein the preservation is effected to nominal H5 (AS 1604.1-2012) standards.

7. A method according to claim 1, wherein the method comprises at least one vacuum step.

8. A method according to claim 7, wherein the at least one vacuum step is carried out between about 0 kPa and about 95 kPa.

9. A method according to claim 1, wherein the method comprises at least one pressure step.

10. A method according to claim 9, wherein the at least one pressure step is carried out between about 0 kPa and about +1450 kPa.

11. Preserved timber, when so-preserved by a method as defined in claim 1.

12. A preservative concentrate for the treatment of timber at substantially ambient temperature, the preservative comprising: creosote present in the concentrate in an amount of about 70% to about 95% w/w; and at least two surfactants comprising a non-ionic surfactant and an anionic surfactant, such that when the preservative is diluted with a predetermined quantity of water, the creosote is present as an oil-in-water macroemulsion or microemulsion; and wherein the non-ionic surfactant is ethoxylated castor oil and the anionic surfactant comprises a calcium alkylbenzene sulfonate or sodium dodecylbenzene sulfonate; and wherein the non-ionic surfactant is present in an amount of from 1% to about 20% w/w.

13. A timber preservative concentrate according to claim 12, wherein the anionic surfactant is calcium dodecylbenzene sulfonate present in the preservative concentrate in an amount of up to about 10% w/w.

14. A timber preservative concentrate according to claim 12, further comprising an anti-foaming agent and/or a fire retardant.

15. A timber preservative concentrate according to claim 12, wherein the anionic surfactant is calcium dodecylbenzene sulfonate present in the preservative in an amount of up to about 20% w/w.

16. A timber preservative concentrate according to claim 12, wherein the at least two surfactants further comprise at least one cationic surfactant.

17. A timber preservative formulation, the formulation comprising: a predetermined amount of a timber preservative concentrate as defined according to claim 12, and a predetermined amount of water; wherein upon mixing, the creosote is present in the formulation in an amount of from about 15% w/w to about 40% w/w as an oil-in-water macroemulsion or microemulsion and provides for the treatment of timber at substantially ambient temperature.

18. A timber preservative formulation according to claim 17, wherein the predetermined amount of water is up to about 90% w/w with respect to the creosote.

19. A timber preservative formulation according to claim 17, wherein the amount of creosote in the formulation is up to about 25% w/w.

20. The timber preservative formulation according to claim 17, wherein the preservative is configured so as to not substantially form crystals at ambient temperatures.

21. The preservative concentrate of claim 12, wherein the ethoxylated castor oil has between about 30 mol and about 60 mol of ethylene oxide.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) An embodiment of the invention will now be described with reference to the accompanying Figures, in which:

(2) FIG. 1 is a comparative photograph taken of Radiata pine posts (left hand side) treated at ambient temperature with water-based creosote according to the present invention to nominal H5 retention, compared with commercially sourced H4 HTC-treated posts (right hand side). The photograph was taken one week after treatment and environmental exposure.

(3) FIG. 2 relates to sample 11d(i), taken from Example 11, below. Sample 11d(i) consists essentially of 1% w/w DDAC+19% w/w creosote and was photographed 15 minutes after the addition of water, wherein there was some emulsification which broke quickly and separated with the heavy oily residue not emulsified (FIG. 2a), 1 hour after the addition of water, in which the components had separated almost completely (FIG. 2b), 24 hours after the addition of water at which time only a small portion of material remained emulsified with the rest precipitated and coalesced into a dark oily material (FIG. 2c), 1 minute after re-mixing following 24 hours of standing, at which point the solution does re-emulsify but requires constant agitation (FIG. 2d), and 15 minutes after re-mixing, at which time it looks similar to that observed upon standing for 24 hours (FIG. 2e).

(4) The following non-limiting Examples further illustrate some embodiments of the present invention.

EXAMPLES

(5) A water-based product for ambient temperature creosote treatment has been developed that largely addresses many of the principal issues associated with high temperature creosote (HTC), namely the appearance, odour and handling of the treated timberand the conditions under which it is applied. Timber treated with the inventive water-based creosote product is light brown in appearance, rather than black (see, FIG. 1). The timber treated with the inventive formulation is less prone to exudation of dark, viscous liquids that make the handling of the pole difficult and hazardous.

(6) One everyday comparative example of some of the advantages of the present invention relates to the use of treated timber bridging over a river. With conventional HTC-treated timber, creosote is prone to leaching out of the treated wood and into the water, thereby contaminating the river. By comparison, it is found that timber treated by the inventive process and employed in an otherwise identical environment gives rise to little or no leaching of the creosote into the water. The environmental benefits are clear in this regard.

(7) The inventive water-based creosote product has the significant advantage that it is applied at ambient temperature (rather than having to be heated as is the case for HTC). This reduces the vapour emissions at the treatment plant, providing a safer, less hazardous work environment, as well as substantially reducing the odour at the treatment plant. To this end, it will be appreciated that governmental regulatory agencies, such as the United States EPA, are becoming ever-more watchful of technologies that either pollute the environment, or endanger technicians working in the vicinity.

(8) The water-based creosote formulation is formed by combining creosote with a mixture of a non-ionic surfactant (e.g., ethoxylated castor oil) and an anionic surfactant (e.g., calcium dodecylbenzene sulfonate). Anti-foamer/s and/or fire retardant/s are optional ingredients.

(9) Any suitable anti-foam or fire retardants can be used. For example, in some embodiments, commercially available anti-foam marketed as Dow Corning 1410 is used.

(10) Exemplary concentrates have the compositions outlined below. These exemplary concentrates are effective for treating timber at ambient conditions as is described herein. The exemplary concentrates can be diluted with water to the appropriate solution strength and used to treat both hardwoods and softwoods. The ratio of creosote to emulsifier can vary, whilst still adequately performing the treatment function. Similarly, where two or more emulsifiers are applied, the ratio of the two emulsifiers can vary; the product still performs satisfactorily.

(11) The timber treated with the disclosed formulation has been shown to be as efficacious, in respect of its preservative qualities, as that treated with standard HTC creosote processes. Moreover, handling, storage and in situ construction using the disclosed formulation is significantly enhanced by comparison with traditional HTC-based creosote formulations.

Example 1

(12) An exemplary concentrate: creosote about 92% w/w; and no water.

(13) TABLE-US-00001 Ingredient Conc. % w/w Creosote (conforming with AS 1604.1-2012) 91.99 Castor oil, ethoxylated (ECO) 3.88 Calcium dodecylbenzene sulfonate, mixed with 3.88 co-solvents (e.g., 2-ethylhexanol, propylene glycol) Anti-foam 0.25 Water 0.00 100

(14) A range of formulations were considered, including: various ratios of emulsifier to creosote; for a given total emulsifier concentration, different ratios of non-ionic and anionic components; concentrates and work solutions examined; emulsion properties compared with those for Lonza MK265-type system, which utilises LET75 as the emulsifier.

(15) TABLE-US-00002 Ingredient Conc. % w/w Creosote (conforming with AS 1604.1-2012) 91.99 Castor oil, ethoxylated (ECO) 3.37 Calcium dodecylbenzene sulfonate, mixed with 4.50 co-solvents (e.g., 2-ethylhexanol, propylene glycol) Anti-foam 0.25 Water 0.00 100

(16) TABLE-US-00003 Ingredient Conc. % w/w Creosote (conforming with AS 1604.1-2012) 91.99 Castor oil, ethoxylated (ECO) 2.88 Calcium dodecylbenzene sulfonate, mixed with 4.88 co-solvents (e.g., 2-ethylhexanol, propylene glycol) Anti-foam 0.25 Water 0.00 100

(17) TABLE-US-00004 Ingredient Conc. % w/w Creosote (conforming with AS 1604.1-2012) 91.99 Castor oil, ethoxylated (ECO) 4.88 Calcium dodecylbenzene sulfonate, mixed with 2.88 co-solvents (e.g., 2-ethylhexanol, propylene glycol) Anti-foam 0.25 Water 0.00 100

Example 2

(18) A concentrate that can be diluted with water; a relatively high ECO:ABS ratio:

(19) TABLE-US-00005 Ingredient Conc. % w/w Creosote (conforming with AS 1604.1-2012) 70.00 Castor oil, ethoxylated (ECO) 17.50 Alkybenzene sulfonic acid (ABS) 2.50 Anti-foam 0.25 Water 9.75 100

Example 3

(20) A concentrate that can be diluted with water; a relatively high ECO:ABS ratio:

(21) TABLE-US-00006 Ingredient Conc. % w/w Creosote (conforming with AS 1604.1-2012) 70.00 Castor oil, ethoxylated (ECO) 2.50 Alkybenzene sulfonic acid (ABS) 2.50 Anti-foam 0.25 Water 24.75 100

Example 4

(22) A concentrate that can be diluted with water; a relatively high ECO:ABS ratio:

(23) TABLE-US-00007 Ingredient Conc. % w/w Creosote (conforming with AS 1604.1-2012) 70.00 Castor oil, ethoxylated (ECO) 2.57 Alkybenzene sulfonic acid (ABS) 3.43 Anti-foam 0.25 Water 23.75 100

Example 5

(24) A concentrate, free of water, which can be diluted with water for the treatment of timber. This example has a relatively high creosote to total emulsifier ratio, hence is relatively cost effective:

(25) TABLE-US-00008 Ingredient Conc. % w/w Creosote (conforming with AS 1604.1-2012) 91.99 Castor oil, ethoxylated (ECO) 3.37 Alkybenzene sulfonic acid (ABS) 4.50 Anti-foam 0.25 Water 0.00 100

Example 6

(26) A concentrate, free of water, which can be diluted with water for the treatment of timber. This example has a relatively high creosote to total emulsifier ratio, hence is relatively cost effective:

(27) TABLE-US-00009 Ingredient Conc. % w/w Creosote (conforming with AS 1604.1-2012) 92.11 Castor oil, ethoxylated (ECO) 3.38 Alkybenzene sulfonic acid (ABS) 4.51 Anti-foam 0.00 Water 0.00 100

(28) The ethoxylated castor oil (ECO) can contain a range of EO units, typically between about 30 and 60 mol EO. For example, emulsification can be achieved with ECO which contains 36 mole EO. The skilled person will appreciate that other surfactants may be just as efficacious.

(29) A range of additives can be included in the formulations: for instance, copper amine preservatives, e.g., copper azole, SDI-1 mimetic compounds, boron containing additives including disodium octaborate, boric acid and borate-ethanolamine solutions, and wax emulsions, e.g., paraffin wax emulsion.

Example 7

(30) A concentrate, further comprising one or more co-preservatives in the form of complex II succinate-dehydrogenase compounds also known as SDI or SDHI fungicides present in a range of weight percents. SDI or SDHI fungicides comprise compounds such as Benodanil, Flutolanil, Mepronil, Fluopyram, Fenfuram, Carboxin, Oxycarboxin, Thifluzamide, Bixafen, Fluxapyroxad, Furametpyr, Isopyrazam, Penflufen, Penthiopyrad, Sedaxene and Boscalid:

(31) TABLE-US-00010 Ingredient Conc. % w/w Creosote (conforming with AS 1604.1-2012) 93.00 Penflufen 1.00 Castor oil, ethoxylated (ECO) 3.00 Alkybenzene sulfonic acid (ABS) 3.00 Anti-foam 0.00 Water 0.00 100

Example 8

(32) A concentrate as described above in respect of Example 2, was diluted 1:1 with tap water at ambient temperature; and mixed thoroughly. The formation of an oil-in-water emulsion was observed. The resultant diluted formulation was then used to treat a Radiata pine pole by vacuum-pressure treatment. The treated pole was left to dry at ambient temperature for three days, at which time it was compared visually with an equivalent pole treated via a prior art HTC process. The pole treated according to this example exhibited a lighter coloration, fewer noticeable odoriferous emissions, and was less greasy to the touch.

Example 9

(33) A concentrate as described above in respect of Example 1, was diluted 2:1 with tap water at ambient temperature; and mixed thoroughly. The formation of an oil-in-water emulsion was observed. The resultant diluted formulation was then coated upon a hardwood sleeper employed along a train line, by brushing, in situ. The product was simple and convenient to use for remedial treatment of timbers already in service.

Example 10

(34) Examples of working solutions of creosote/non-ionic surfactant are provided below. However, the invention may also be embodied in a concentrate that is free of water. In the examples provided below, Creosote was premixed with surfactant/solvent at a ratio of surfactant/creosote not exceeding 1 to 19. The product was combined with water at a ratio of 1 part product to 4 parts water and agitated under low to medium shear. Formulations may optionally contain anti-foam; a typical amount is 0.25% w/w. A typical emulsifier active concentration in the product is provided, but it would be appreciated by one of skill in the art that this may vary from product-to-product. The overall emulsifier concentration in the examples can be calculated from the emulsifier active concentration in the product, and the concentration of the product in the creosote work solution. The creosote concentration in the work solution can vary, e.g., depending upon the intended Hazard Class, the species being treated and the process used. The surfactant concentration can vary, but is practically <5% w/w.

(35) Examples 10a to 10k demonstrate the use of non-ionic surfactants

(36) TABLE-US-00011 Example 10a(i) 10a(ii) 10a(iii) 10a(iv) 10a(v) 10a(vi) Ingredient % w/w % w/w % w/w % w/w % w/w % w/w Creosote 19 19 19 19 19 19 (conforming with AS1604 - 2012) Nonyl phenol 1 2 3 4 5 10 ethoxylate (15 mol EO), ~95% active emulsifier Water 80 79 78 77 76 71 Total 100 100 100 100 100 100

(37) TABLE-US-00012 Example 10b(i) 10b(ii) 10b(iii) 10b(iv) 10b(v) 10b(vi) Ingredient % w/w % w/w % w/w % w/w % w/w % w/w Creosote 19 19 19 19 19 19 (conforming with AS1604 - 2012) C9-C11 alcohol 1 2 3 4 5 10 ethoxylate (8 mol EO), ~95% active emulsifier Water 80 79 78 77 76 71 Total 100 100 100 100 100 100

(38) TABLE-US-00013 Example 10c(i) 10c(ii) 10c(iii) 10c(iv) 10c(v) 10c(vi) Ingredient % w/w % w/w % w/w % w/w % w/w % w/w Creosote 19 19 19 19 19 19 (conforming with AS1604 - 2012) C10-C12 1 2 3 4 5 10 alcohol ethoxylate (12 mol EO), ~95% active emulsifier Water 80 79 78 77 76 71 Total 100 100 100 100 100 100

(39) TABLE-US-00014 Example 10d(i) 10d(ii) 10d(iii) 10d(iv) 10d(v) 10d(vi) Ingredient % w/w % w/w % w/w % w/w % w/w % w/w Creosote 19 19 19 19 19 19 (conforming with AS1604 - 2012) Alkyl 1 2 3 4 5 10 polyglucoside based on a fatty acid, e.g., lauric acid. ~50% active emulsifier Water 80 79 78 77 76 71 Total 100 100 100 100 100 100

(40) TABLE-US-00015 Example 10e(i) 10e(ii) 10e(iii) 10e(iv) 10e(v) 10e(vi) Ingredient % w/w % w/w % w/w % w/w % w/w % w/w Creosote 19 19 19 19 19 19 (conforming with AS1604 - 2012) Alkyl 1 2 3 4 5 10 polyglucoside based on a fatty acid, e.g., lauric acid. ~50% active emulsifier Water 80 79 78 77 76 71 Total 100 100 100 100 100 100

(41) TABLE-US-00016 Example 10f(i) 10f(ii) 10f(iii) 10f(iv) 10f(v) 10f(vi) Ingredient % w/w % w/w % w/w % w/w % w/w % w/w Creosote 19 19 19 19 19 19 (conforming with AS1604 - 2012) Secondary 1 2 3 4 5 10 alcohol ethoxylate, e.g., softenol 90. ~95% active emulsifier Water 80 79 78 77 76 71 Total 100 100 100 100 100 100

(42) TABLE-US-00017 Example 10g(i) 10g(ii) 10g(iii) 10g(iv) 10g(v) 10g(vi) Ingredient % w/w % w/w % w/w % w/w % w/w % w/w Creosote 19 19 19 19 19 19 (conforming with AS1604 - 2012) Ethoxylated 1 2 3 4 5 10 sorbitan oleate, e.g., Tween 80. ~95% active emulsifier Water 80 79 78 77 76 71 Total 100 100 100 100 100 100

(43) TABLE-US-00018 Example 10h(i) 10h(ii) 10h(iii) 10h(iv) 10h(v) 10h(vi) Ingredient % w/w % w/w % w/w % w/w % w/w % w/w Creosote 19 19 19 19 19 19 (conforming with AS1604 - 2012) Ethoxylated 1 2 3 4 5 10 castor oil, e.g., ~36 mol EO Water 80 79 78 77 76 71 Total 100 100 100 100 100 100

(44) TABLE-US-00019 Example 10i(i) 10i(ii) 10i(iii) 10i(iv) 10i(v) 10i(vi) Ingredient % w/w % w/w % w/w % w/w % w/w % w/w Creosote 19 19 19 19 19 19 (conforming with AS1604 - 2012) Ethoxylated 1 2 3 4 5 10 castor oil, e.g., ~40 mol EO Water 80 79 78 77 76 71 Total 100 100 100 100 100 100

(45) TABLE-US-00020 Example 10j(i) 10j(ii) 10j(iii) 10j(iv) 10j(v) 10j(vi) Ingredient % w/w % w/w % w/w % w/w % w/w % w/w Creosote 19 19 19 19 19 19 (conforming with AS1604 - 2012) Ethoxylated 1 2 3 4 5 10 castor oil, e.g., ~54 mol EO Water 80 79 78 77 76 71 Total 100 100 100 100 100 100

(46) TABLE-US-00021 Example 10k(i) 10k(ii) 10k(iii) 10k(iv) 10k(v) 10k(vi) Ingredient % w/w % w/w % w/w % w/w % w/w % w/w Creosote 19 19 19 19 19 19 (conforming with AS1604 - 2012) Coco- 1 2 3 4 5 10 alkyldimethyl amine-N-oxide Water 80 79 78 77 76 71 Total 100 100 100 100 100 100

(47) TABLE-US-00022 Example 10l(i) 10l(ii) 10l(iii) 10l(iv) 10l(v) 10l(vi) Ingredient % w/w % w/w % w/w % w/w % w/w % w/w Creosote 19 19 19 19 19 19 (conforming with AS1604 - 2012) cocoamido 1 2 3 4 5 10 propylbetaine Water 80 79 78 77 76 71 Total 100 100 100 100 100 100

(48) TABLE-US-00023 Example 10m(i) 10m(ii) 10m(iii) 10m(iv) 10m(v) 10m(vi) Ingredient % w/w % w/w % w/w % w/w % w/w % w/w Creosote 19 19 19 19 19 19 (conforming with AS1604 - 2012) benzalkonium 1 2 3 4 5 10 chloride Water 80 79 78 77 76 71 Total 100 100 100 100 100 100

(49) TABLE-US-00024 Example 10n(i) 10n(ii) 10n(iii) 10n(iv) 10n(v) 10n(vi) Ingredient % w/w % w/w % w/w % w/w % w/w % w/w Creosote 19 19 19 19 19 19 (conforming with AS1604 - 2012) Cetrimonium 1 2 3 4 5 10 chloride Water 80 79 78 77 76 71 Total 100 100 100 100 100 100

(50) TABLE-US-00025 Example 10o(i) 10o(ii) 10o(iii) 10o(iv) 10o(v) 10o(vi) Ingredient % w/w % w/w % w/w % w/w % w/w % w/w Creosote 19 19 19 19 19 19 (conforming with AS1604 - 2012) N,N-Didecyl 1 2 3 4 5 10 N,N-dimethyl- ammonium chloride Water 80 79 78 77 76 71 Total 100 100 100 100 100 100

(51) TABLE-US-00026 Example 10p(i) 10p(ii) 10p(iii) 10p(iv) 10p(v) 10p(vi) Ingredient % w/w % w/w % w/w % w/w % w/w % w/w Creosote 19 19 19 19 19 19 (AS1604 - 2012) Morpholine 0.5 1 1.5 2 2.5 5 oleate ethoxylated 0.5 1 1.5 2 2.5 5 sorbitan oleate Water 80 79 78 77 76 71 Total 100 100 100 100 100 100

(52) TABLE-US-00027 Example 10q(i) 10q(ii) 10q(iii) 10q(iv) 10q(v) 10q(vi) Ingredient % w/w % w/w % w/w % w/w % w/w % w/w Creosote 19 19 19 19 19 19 (AS1604 - 2012) Morpholine 0.5 1 1.5 2 2.5 5 oleate alkyl 0.5 1 1.5 2 2.5 5 polyglucocide based on lauric acid Water 80 79 78 77 76 71 Total 100 100 100 100 100 100

(53) TABLE-US-00028 Example 10r(i) 10r(ii) 10r(iii) 10r(iv) 10r(v) 10r(vi) Ingredient % w/w % w/w % w/w % w/w % w/w % w/w Creosote 19 19 19 19 19 19 (AS1604 - 2012) Morpholine 0.5 1 1.5 2 2.5 5 oleate Castor oil 0.5 1 1.5 2 2.5 5 ethoxylate Water 80 79 78 77 76 71 Total 100 100 100 100 100 100

(54) Examples 10s to 10v demonstrate the use of combined non-ionic/cationic surfactants.

(55) TABLE-US-00029 Example 10s(i) 10s(ii) 10s(iii) 10s(iv) 10s(v) 10s(vi) Ingredient % w/w % w/w % w/w % w/w % w/w % w/w Creosote 19 19 19 19 19 19 (AS1604 - 2012) Synthecol 0.5 1 1.5 2 2.5 5 CAB (cocoamido propylbetaine CAS 61789- 40-0) ethoxylated 0.5 1 1.5 2 2.5 5 sorbitan oleate Water 80 79 78 77 76 71 Total 100 100 100 100 100 100

(56) TABLE-US-00030 Example 10t(i) 10t(ii) 10t(iii) 10t(iv) 10t(v) 10t(vi) Ingredient % w/w % w/w % w/w % w/w % w/w % w/w Creosote 19 19 19 19 19 19 (AS1604 - 2012) benzalkonium 0.5 1 1.5 2 2.5 5 chloride alkyl 0.5 1 1.5 2 2.5 5 polyglucocide based on lauric acid Water 80 79 78 77 76 71 Total 100 100 100 100 100 100

(57) TABLE-US-00031 Example 10u(i) 10u(ii) 10u(iii) 10u(iv) 10u(v) 10u(vi) Ingredient % w/w % w/w % w/w % w/w % w/w % w/w Creosote 19 19 19 19 19 19 (conforming with AS1604 - 2012) cetrimonium 0.5 1 1.5 2 2.5 5 chloride Castor oil 0.5 1 1.5 2 2.5 5 ethoxylate (highly ethoxylated Water 80 79 78 77 76 71 Total 100 100 100 100 100 100

(58) TABLE-US-00032 Example 10v(i) 10v(ii) 10v(iii) 10v(iv) 10v(v) 10v(vi) Ingredient % w/w % w/w % w/w % w/w % w/w % w/w Creosote 19 19 19 19 19 19 (conforming with AS1604 - 2012) N,N-Didecyl- 0.5 1 1.5 2 2.5 5 N,N-dimethyl- ammonium chloride ethoxylated 0.5 1 1.5 2 2.5 5 sorbitan oleate Water 80 79 78 77 76 71 Total 100 100 100 100 100 100

Example 11

(59) In the exemplary solutions listed below, creosote was premixed with surfactant/solvent at a ratio of surfactant/creosote ratio not exceeding 1 to 19. The premixed product was combined with water at a ratio of 1 part product to 4 parts water and agitated under low to medium shear conditions.

(60) TABLE-US-00033 Non-ionic surfactants Example Chemical name HLB % active 11a(i) Cetyl-oleyl ethoxylate (2 mol EO) 6 >95 11a(ii) C10-12 alcohol ethoxylate (7 mol EO) 12.1 >95 11a(iii) C9-C11 alcohol ethoxylate (8 mol EO) 13.7 >95 11a(iv) C10-12 alcohol ethoxylate (12 mol EO) 14.4 >95 11a(v) Nonyl phenol ethoxylate (15 mol EO) 15 >95 11a(vi) Castor oil ethoxylate (highly ethoxylated) >95 11a(vii) Fatty amine oxide 33-35 11a(viii) Alkyl polyglucocide based on lauric acid 50 11a(ix) Sorbitan mono oleate (20 EO) 15 >95 11a(x) Secondary alcohol ethoxylate >95

(61) A number of different surfactants from different ionic charge groups were tested. These were tested at a level of 5% weight over weight with creosote. The surfactants were included as supplied, i.e., no account was made for the active levelrather, 5% w/w of the supplied surfactant was added. Non-ionic surfactants were also combined with cationic surfactants as a mixed emulsifier in subsequent tests.

(62) TABLE-US-00034 Anionic surfactants Example Chemical name HLB % active 11b(i) Sulfonated castor oil 75 11b(ii) Calcium dodecyl benzene sulfonate in 70 butanol 11b(iii) Sodium dodecyl benzene sulfonate >95 11b(iv) Morpholine oleate >95 11b(v) Crisilic acid soap

(63) TABLE-US-00035 Cationic and amphoteric surfactants Example Chemical name HLB % active 11c(i) Cocoamido propylbetaine 30-32 11c(ii) Alkylpolyglycol ether ammonium methyl chloride 11c(iii) N,N-Didecyl-N,N-dimethylammonium 80-82 chloride 11c(iv) Benzylkonium chloride 50-52 11c(v) Didecyldimethyl ammonium carbonate 48.5-51.5 11c(vi) Cetrimonium chloride 25

(64) TABLE-US-00036 Combined surfactants % % Example Surfactant 1 w/w Surfactant 2 w/w 11d(i) N,N-Didecyl-N,N- 1 dimethylammonium chloride 11d(ii) N,N-Didecyl-N,N- 0.8 Castor oil 0.2 dimethylammonium ethoxylate chloride (highly ethoxylated) 11d(iii) N,N-Didecyl-N,N- 0.8 C9-C11 alcohol 0.2 dimethylammonium ethoxylate chloride (8 mol EO) 11d(iv) N,N-Didecyl-N,N- 0.8 C10-12 alcohol 0.2 dimethylammonium ethoxylate chloride (7 mol EO) 11d(v) N,N-Didecyl-N,N- 0.8 Cocoamido 0.2 dimethylammonium propylbetaine chloride 11d(vi) N,N-Didecyl-N,N- 0.8 C10-12 alcohol 0.2 dimethylammonium ethoxylate chloride (12 mol EO) 11d(vii) N,N-Didecyl-N,N- 0.8 Fatty amine 0.2 dimethylammonium oxide chloride 11d(viii) N,N-Didecyl-N,N- 0.8 Secondary 0.2 dimethylammonium alcohol chloride ethoxylate 11d(ix) N,N-Didecyl-N,N- 0.8 Nonyl phenol 0.2 dimethylammonium ethoxylate chloride (15 mol EO) 11d(x) N,N-Didecyl-N,N- 0.8 Sorbitan 0.2 dimethylammonium mono oleate chloride (80 EO) 11d(xi) N,N-Didecyl-N,N- 0.8 Alkyl 0.2 dimethylammonium polyglucocide chloride based on lauric acid 11d(xii) N,N-Didecyl-N,N- 0.8 Cetyl-oleyl 0.2 dimethylammonium ethoxylate chloride (2 mol EO) 11d(xiii) Calcium dodecyl 1 benzene sulfonate in butanol 11d(xiv) Cocoamido 1 propylbetaine 11d(xv) Castor oil 1 ethoxylate (highly ethoxylated) 11d(xvi) Oleic acid 0.7 Morpholine 11d(xvii) DDBSA 0.74 50%NaOH 11d(xviii) Morpholine 1 11d(xix) Fatty amine 1 oxide 11d(xx) Secondary 1 alcohol ethoxylate 11d(xxi) Nonyl phenol 1 ethoxylate (15 mol EO) 11d(xxii) C10-12 alcohol 1 ethoxylate (12 mol EO) 11d(xxiii) Sorbitan 1 mono oleate (80 EO) 11d(xxiv) Alkyl 1 polyglucocide based on lauric acid 11d(xxv) Castor oil 1 sulfonate 11d(xxvi) Cetyl-oleyl 1 ethoxylate (2 mol EO) 11d(xxvii) Benzylkonium 1 chloride 11d(xxviii) Benzylkonium 0.8 Castor oil 0.2 chloride ethoxylate (highly ethoxylated) 11d(xxix) Benzylkonium 0.8 Crillet4 0.2 chloride 11d(xxx) Benzylkonium 0.8 Alkyl 0.2 chloride polyglucocide based on lauric acid 11d(xxxi) Benzylkonium 0.8 Cocoamido 0.2 chloride propylbetaine

(65) Sample 11d(i), being 1% w/w DDAC+19% w/w creosote was photographed 15 minutes after the addition of water (see, FIG. 2a), 1 hour after the addition of water (see, FIG. 2b), 24 hours after the addition of water (see, FIG. 2c), 1 minute after re-mixing following 24 hours of standing (see, FIG. 2d), and 15 minutes after re-mixing (see, FIG. 2e).

INDUSTRIAL APPLICABILITY

(66) As related below, there are a range of issues associated with high temperature creosote. These are listed blow, along with a description as to how the disclosed formulations addresses each, in turn:

(67) HTC is used hot, e.g., at 90 C. to treat timber. This requires heating of the working solution (i.e., neat creosote), jacketed cylinder and lagged pipe work. The present invention is advantageous in that inventive water-based product is used at ambient temperature in a conventional waterborne treatment plant. This saves energy, as well as reduces odour around treatment plant.

(68) Hot creosote results in vapour emissions which present a safety issue to workers. Creosote is prone to causing skin sensitisation of workers who come in close and frequent contact with treated commodities. The present invention is advantageous in that the water-based product is used at ambient temperature (about 5 to about 60 C.), reducing creosote vapour emissions and odour.

(69) High temperature creosote must be kept warm to prevent crystallisation of certain components. The present invention is advantageous in that the emulsion concentrate is stable at low temperature, i.e., crystallisation of components does not occur to any great extent.

(70) HTC-treated timber is typically black, oily to touch. It often exudes viscous, black liquid that makes the timber difficult to handle. The present invention is advantageous in that the appearance of timber treated with the inventive water-based emulsion is considerably lighter than that of HTC-treated timber. Once dry, it is not oily to touch, nor has any timber showed signs of bleeding, even when exposed to direct sunlight on extremely hot days, e.g., daily temperature maximums of 45 C.

(71) In conventional HTC processes, the use of solvent carriers is becoming increasingly regulated. The present invention is advantageous in that it uses water as the carrier; there are no VOC emissions resultant from the choice of carrier.

(72) Although the invention has been described with reference to specific examples it will be appreciated by those skilled in the art that the invention may be embodied in many other forms. As such, reference throughout this specification to one embodiment or an embodiment means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases in one embodiment or in an embodiment in various places throughout this specification are not necessarily all referring to the same embodiment, but may. The particular features, structures or characteristics may be combined in any suitable manner, as would be apparent to one of ordinary skill in the art from this disclosure, in one or more embodiments.

(73) In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the invention may be practiced without these specific details. In other instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description. Thus, while there has been described what are believed to be the preferred embodiments of the invention, those skilled in the art will recognise that other and further modifications may be made thereto without departing from the spirit of the invention, and it is intended to claim all such changes and modifications as fall within the scope of the invention.

(74) It will be appreciated that the above-described invention provides for an efficacious creosote-based wood preservative formulation that substantially does not bear the undesirable odour, toxicity and environmental disbenefits that characterise the more traditional HTC creosote treatments characterising the prior art.