SUB-MICRON COMPOSITIONS
The invention relates to sub-micron compositions, and methods of preparing such compositions, in particular for the treatment of substrates against biological degradation biological pests.
1 . A method of preparing a composition comprising sub-micron particles, containing or coated with an active agent(s), the method comprising at least the steps of:
a) (i) dispersing sub-micron particles in a solvent(s);
(ii) adding to the dispersion, a formulation containing the active agent(s) dissolved in a suitable solvent in a manner sufficient to achieve substantial uniformity of the mixture (or vice versa); or
b) dispersing sub-micron particles in a solvent(s) whilst concurrently or sequentially dissolving an active agent in said solvent in a manner sufficient to achieve substantial uniformity of the mixture; and
c) altering the physicochemical environment within the dispersion to cause the active agent to fall out of solution as a sub-micron layer in or on the sub-micron particles.
2 . The method according to claim 1 , wherein the active agent is a biocide, colouring agent or a water repellent agent or a mixture thereof.
3 . The method according to claim 1 , wherein the alteration in the physicochemical environment can be by one or more of; change in pH, introduction of another moiety which reacts with the active agent to cause precipitation, heating which can change the isoelectric point, heating which can remove sufficient solvent such that the solubility product of the active agent is exceeded, addition of a non-solvent of the active agent to cause precipitation or addition of a solute which causes precipitation of the active agent.
4 . The method according to claim 1 , wherein the physicochemical environment is altered while agitating the result of step (a) (ii) or (b) such that the active agent precipitates as a sub-micron layer on the sub-micron particles and/or within any porosity in the sub-micron particles.
5 . The method according to claim 1 , wherein the sub-micron particle dispersion includes water.
6 . The method according to claim 1 , wherein the sub-micron particles are selected from natural or synthetic organic or inorganic clays.
7 . The method according to claim 6 , wherein the natural clays are selected from any one or more of montmorillinite, hectorite, smectite, bentonite, halloysite, talcite, and allophone.
8 . The method according to claim 1 , wherein the solvents are selected from any one or more of water and organic solvents or mixtures thereof.
9 . The method according to claim 1 , wherein the solvent(s) are miscible.
10 . The method according to claim 1 , wherein solvent(s) are immiscible.
11 . The method according to claim 1 , wherein one or more of the solvents can be in a super critical state.
12 . The method according to claim 11 , wherein one or more of the solvents can be a super critical solvent in admixture with a co-solvent.
13 . The method according to claim 11 , wherein the solvent in the super critical state is carbon dioxide.
14 . The method according to claim 12 , wherein the co-solvent is selected from any one or more of acetone, methanol, ethanol, or isopropanol.
15 . The method according to claim 1 , wherein the solvents are removed and/or recovered by air drying or vacuum distillation.
16 . The method according to claim 1 , wherein the active agent is deposited as mono or poly-molecular layers in or on the sub-micron particles.
17 . The method according to claim 1 , wherein a chelating agent, dispersant and/or a surfactant is added during or after the addition of the active agent composition to the sub-micron particles.
18 . The method according to claim 1 , wherein the sub-micron composition formed is subsequently concentrated by centrifugation.
19 . The method according to claim 1 , wherein the sub-micron particles are pre-treated to remove trace metals.
20 . The method according to claim 19 , wherein pre-treatment to remove trace metals includes use of a chelating agent, or acidification to change the surface charge.
21 . The method according to claim 1 , wherein the submicron composition formed is milled in a form containing one or more solvents.
22 . The method according to claim 1 , wherein the submicron composition formed is milled in dry form after the solvent or solvents have been removed.
23 . The method according to claim 1 , wherein the active agent formulation is an aqueous solution of a biologically active metal.
24 . The method according to claim 23 , wherein the biologically active metal is copper or zinc or mixtures thereof.
25 . The method according to claim 23 , wherein the biologically active metal is present as a chelate.
26 . The method according to claim 25 , wherein the chelate of said biologically active metal is selected from 8-hydroxyquinoline, pyridinethione, 1,10-phenanthroline, N-nitrosolated cyclohexylhydroxylamine, amidoxamine, hydroxamic acid, thiohydroxamic acid, and/or N-nitrosyl alkylhydroxylamine.
27 . The method according to claim 1 , wherein the method includes adjusting the pH of the formulation containing the active agent prior to addition to the sub-micron particle dispersion in step (a) (ii).
28 . The method according to claim 1 , wherein step (c) includes adjusting the pH using an acid or base.
29 . The method according to claim 1 , wherein one or more additional active agents are added concurrently or sequentially to the first prepared sub-micron dispersion.
30 . The method according to claim 1 , wherein the sub-micron particles are chemically modified prior to use in the method.
31 . The method according to claim 30 , wherein the sub-micron particles are peptised.
32 . The method according to claim 31 , wherein the sub-micron particles are peptised using polyacrylates, polyphosphates, and/or pyrophosphates.
33 . The method according to claim 1 , wherein the active agent is an insecticide, bacteriocide or herbicide.
34 . The method according to claim 33 , wherein the active agent is selected from any one or more selected from any one or more of chlorothalonil, iodopropynyl butylcarbamate bifenthrin, deltamethrin, permethrin, or imidacloprid.
35 . The method according to claim 8 , wherein the organic solvent is xylene.
36 . The method according to claim 1 , wherein the solvent is recovered by vacuum distillation.
37 . The method according to claim 36 , wherein the solvent recovery is facilitated by use of RF energy.
38 . The method according to claim 1 , wherein the solvent is recovered during the process of applying the biocide species to a substrate.
39 . A composition prepared according to the method of claim 1 .
40 . A stable sub-micron composition including sub-micron particles containing, or coated with, a sub-micron layer of at least one biocide, for the treatment of substrates against biological degradation or biological pests.
41 . The sub-micron composition according to claim 40 wherein the biocide is cupric hydroxide.
42 . The sub-micron composition according to claim 40 wherein the biocide is cupric hydroxide and tebuconazole or propiconazole or a combination thereof.
43 . The sub-micron composition according to claim 40 wherein the biocide is basic copper carbonate.
44 . The sub-micron composition according to claim 40 wherein the biocide is (i) basic copper carbonate and (ii) tebuconazole or propiconazole, or a combination thereof.
45 . The sub-micron composition according to claim 40 wherein the biocide is cupric oxide.
46 . The sub-micron composition according to claim 40 wherein the biocide is cupric oxide and tebuconazole or propiconazole or a combination thereof.
47 . The sub-micron composition according to claim 40 wherein the biocide is (i) basic copper carbonate or cupric hydroxide and (ii) chlorothalonil.
48 . The sub-micron composition according to claim 40 wherein the biocide is Bifenthrin.
49 . The sub-micron composition according to claim 48 wherein the composition is used for treating plants or is included in a resin used in preparation of plywood or laminated veneer lumber.
50 . A method of treating a substrate, wherein the composition of claim 40 is applied to a substrate by dipping, deluging, spraying, brushing or mixing, or vacuum or positive pressure impregnation.
51 . The method according to claim 50 , wherein the composition is applied to the substrate at ambient temperature.
52 . The method according to claim 50 , wherein the composition formed is applied to an organic or inorganic substrate.
53 . The method according to claim 52 wherein the substrate is selected from any one or more of wood products, plants, leather, concrete, stone, or metals.