In-process drying for oil-based wood treatments.

Abstract

Generally, the present disclosure relates to a method for treating wood products, the method disclosed in the specification includes the steps of: i) injecting an oil-based preservative into a treatment chamber containing the wood product; ii) pressurizing the treatment chamber containing the wood product and the oil-based preservative to impregnate the wood product with the oil-based preservative; iii) releasing the pressure in the treatment chamber to atmospheric pressure; iv) performing an intermediate drying step; v) draining the oil-based preservative from the treatment chamber after performing the intermediate drying step; and vi) applying a vacuum in the treatment chamber to remove excess preservative from the surface of the impregnated wood product.

Description

[Technical field]

[0001] Related Applications

[0001] This application is based on and claims priority to U.S. Provisional Application No. 63 / 325,857, filed March 31, 2022, and U.S. Provisional Application No. 63 / 427,139, filed November 22, 2022, which are incorporated herein by reference. [Background technology]

[0002]

[0002] Wood and wood-based products intended for heavy duty use (such as, but not limited to, poles, sleepers, and agricultural supports) typically contain 20-40% moisture before preservative treatment, which can migrate into the treatment solution during treatment and, if not precisely controlled, can cause, among other things, preservative destabilization, excessive corrosion, and oxidation of oils, all of which lead to solids formation (observed as sludge or "varnish") in the treatment solution.

[0003] Typically, oil-based wood preservatives, such as creosote, have been used at temperatures above 100°C. At such temperatures, the treated wood leaves the treatment autoclave relatively "dry to the touch" with minimal free liquid on the surface. Modern Cu-organic oil-based wood preservative systems, such as Tanasote S40®, cannot be used at such high temperatures due to chemical instability. Lower application temperatures are therefore required for modern Cu-organic oil-based wood preservative systems, which can result in a "sweaty" or "sticky" surface immediately after treatment under normal working conditions. Currently, wood must be stored in situ at the treatment facility, sometimes for months, before the surface is dry to the touch. Alternatively, the wood is retreated with a system such as creosote in a drying process to remove excess liquid on the surface. In certain jurisdictions, this drying technique is not permitted by regulations. In view of the above, there is a need for improved compositions and methods for overcoming such surface appearances that result in a surface that is dry to the touch immediately after treatment. Summary of the Invention

[0004]

[0004] Generally, the present disclosure is directed to a method for treating wood products. The method disclosed herein includes the steps of: i) injecting an oil-based preservative into a treatment chamber containing the wood product; ii) pressurizing the treatment chamber containing the wood product and the oil-based preservative to impregnate the wood product with the oil-based preservative; iii) releasing the pressure in the treatment chamber to atmospheric pressure; iv) performing an intermediate drying step to improve the surface appearance and reduce free oil on the surface of the wood; v) evacuating the oil-based preservative from the treatment chamber after performing the intermediate "drying" step; and vi) applying a vacuum in the treatment chamber to remove excess preservative from the surface of the impregnated wood product.

[0005] In one embodiment, during the intermediate drying stage, about 5% to about 30% of the oil-based preservative is expelled from the processing chamber.

[0006] In one embodiment, the wood products include one or more of a utility pole, a fence post, and a railroad tie.

[0006]

[0007] In one embodiment, the wood product includes a product formed from one or more of pine, spruce, cedar, fir, hemlock, oak, maple, cherry, eucalyptus, poplar, beech, and aspen.

[0007]

[0008] In one embodiment, when the wood product is impregnated with the oil-based preservative, the temperature of the oil-based preservative is 40 degrees Celsius or higher.

[0009] In one embodiment, when the wood product is impregnated with the oil-based preservative, the temperature of the oil-based preservative is about 60 degrees Celsius.

[0008]

[0010] In one embodiment, during the "drying" step, a vacuum of no greater than a half bar is used to remove excess preservative from the surface of the impregnated wood product.

[0009]

[0011] In one embodiment, the temperature of the oil-based preservative is increased by up to about twenty degrees Celsius (20° C.) during the "drying" stage compared to the temperature during the pressing step.

[0012] In one embodiment, the treatment chamber is pressurized for not less than 5 minutes and not more than 300 minutes to impregnate the wood product with the oil-based preservative.

[0010]

[0013] In one embodiment, after the oil-based preservative is evacuated from the treatment chamber, a vacuum is applied within the treatment chamber for 30 minutes or more to remove excess preservative from the surface of the impregnated wood product.

[0011]

[0014] In one embodiment, in the step of removing the wood product impregnated with the oil-based preservative from the treatment chamber, when the wood product impregnated with the oil-based preservative is removed from the treatment chamber, the temperature of the wood product impregnated with the oil-based preservative from the treatment chamber is 60 degrees Celsius or less.

[0012]

[0015] In one embodiment, the oil-based preservative contains copper as the only biocide.

[0016] In one embodiment, the oil-based preservative comprises copper and at least one organic co-biocide.

[0013]

[0017] In one embodiment, copper is present in the oil-based preservative at greater than or equal to about 0.1% by weight of the oil-based preservative and at less than or equal to about 10% by weight of the oil-based preservative.

[0018] In one embodiment, the at least one organic co-biocide is present at about 0.01% by weight or more of the oil-based preservative and at about 10% by weight or less of the oil-based preservative.

[0014]

[0019] In one embodiment, the at least one organic co-biocide comprises one or more of an isothiazolone, a pyrethroid, a neonicotinoid, a halogenated carbamate, a quaternary ammonium salt, a succinate dehydrogenase inhibitor (SDHI), and / or an azole.

[0015]

[0020] In one embodiment, the impregnated wood product is incubated with the oil-based preservative during an intermediate drying stage for up to 180 minutes.

[0021] In one embodiment, the impregnated wood product is incubated with the oil-based preservative during an intermediate drying stage for up to 60 minutes.

[0016]

[0022] In one embodiment, the present disclosure provides a wood product treated with an oil-based preservative in a treatment chamber.

[0023] Each of the exemplary forms listed above may be combined with one or more of the other exemplary forms listed above in a particular embodiment. For example, all of the exemplary forms listed above may be combined with each other in some embodiments. As another example, any combination of two, three, four, five or more of the twenty exemplary forms listed above may be combined in other embodiments. Thus, the exemplary forms listed above may be utilized in combination with each other in some exemplary embodiments. Alternatively, the exemplary forms listed above may be implemented individually in other exemplary embodiments. Thus, it will be understood that various exemplary embodiments can be realized utilizing the exemplary forms listed above.

[0017]

[0024] These and other features, aspects, embodiments and advantages of the present invention will become better understood with reference to the following description and appended claims.

[0018]

[0025] A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in this specification, and makes reference to the accompanying drawings. [Brief description of the drawings]

[0019] [Figure 1]

[0026] FIG. 1 illustrates the Rueping cycle without the drying step. [Diagram 2]

[0027] FIG. 2 illustrates the Rueping cycle with a drying step. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020]

[0028] Exemplary embodiments of the present disclosure are described in detail below. It will be understood by those skilled in the art that the present disclosure is merely a description of exemplary embodiments and is not intended to limit the broader aspects of the present disclosure.

[0021]

[0029] The present disclosure is generally directed to a method for treating wood products.According to the present disclosure, the method disclosed herein comprises the steps of: i) injecting oil preservative into the treatment chamber containing wood products; ii) pressurizing the treatment chamber containing wood products and oil preservative to impregnate wood products with oil preservative; iii) releasing the pressure of the treatment chamber to atmospheric pressure; iv) partially discharging oily products from the treatment chamber and carrying out intermediate drying stage; v) discharging oil preservative from the treatment chamber after carrying out intermediate drying stage; and vi) applying vacuum in the treatment chamber to remove excess preservative from the surface of impregnated wood products.In one embodiment, when wood products are impregnated with oil preservative, the temperature of oil preservative is below 90°C.

[0022]

[0030] According to the present disclosure, the wood product is treated in a treatment chamber. The treatment chamber may be any suitable chamber for the purpose of treating wood products. For example, the treatment chamber containing the wood product may be a stainless steel pressure cylinder for horizontal loading, or a stainless steel industrial chamber for top loading, etc. In another embodiment, the treatment chamber may be a carbon steel pressure cylinder. Regardless of the specific treatment vessel utilized, it is expected that the treatment vessel is used to treat wood products alone or in combination with an oil-based preservative.

[0023]

[0031] In one embodiment, the method disclosed herein includes injecting a preservative into a treatment chamber containing a wood product. The preservative may be an oil-based preservative. According to the present disclosure, the oil-based preservative may include one or more biocides. For example, the oil-based preservative may include copper (Cu) and at least one co-biocide. In one embodiment, copper is present in the oil-based preservative at about 0.01% to about 10% by weight, such as about 0.5% to about 7.5% by weight, such as about 1.5% to about 5% by weight, or any range therebetween.

[0024]

[0032] According to the present disclosure, the at least one co-biocide may be an organic co-biocide, including, but not limited to, one or more of isothiazolinones, pyrethroids, neonicotinoids, halogenated carbamates, quaternary ammonium salts, succinate dehydrogenase inhibitors (SDHIs), and / or azoles.

[0025]

[0033] In one embodiment, the organic co-biocide may include an isothiazolone, such as, but not limited to, 1,2-benzisothiazolin-3-one ("BIT"), N-(n-butyl)-1,2-benzisothiazolin-3-one, 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one ("DCOIT"), 2-methyl-4-isothiazolin-3-one, 5-chloro-2-methyl-4-isothiazolin-3-one, 2-methyl-4-isothiazolin-3-one, 5-chloro-2-methyl-2H-isothiazol-3-one / 2-methyl-2H-isothiazol-3-one ("CMIT / MIT"), or combinations thereof.

[0026]

[0034] In one embodiment, the organic co-biocide may include pyrethroids, such as, but not limited to, acrinathrin, allethrin, bifenthrin ((2-methyl[1,1'-biphenyl]-3-yl)methyl(1R,3R)-rel-3-[(1Z)-2-chloro-3,3,3-trifluoro-1-propen-1-yl]-2,2-dimethylcyclopropanecarboxylate), chloroprallethrin, cycloprothrin, cyfluthrin, beta-cyfluthrin, cyhalothrin, lambda-cyhalothrin, gamma-cyhalothrin, and the like. cypermethrin, cypermethrin (cyano(3-phenoxyphenyl)methyl 3-(2,2-dichloroethenyl)-2,2-dimethylcyclopropanecarboxylate), alpha-cypermethrin, beta-cypermethrin, theta-cypermethrin, zeta-cypermethrin, cyphenothrin, deltamethrin ((S)-cyano(3-phenoxyphenyl)methyl (1R,3R)-3-(2,2-dibromoethenyl)-2,2-dimethylcyclopropanecarboxylate), dimefluthrin, Esfenvalerate, Etofenprox ((1-[[2-(4-ethoxyphenyl)-2-methylpropoxy]methyl]-3-phenoxybenzene), Fenpropathrin, Fenvalerate, Esfenvalerate, Flucythrinate, Flumethrin, Fluvalinate, Tau-fluvalinate, Halfenprox, Imiprothrin, Kadethrin, Metofluthrin, Permethrin ((3-phenoxyphenyl)methyl 3-(2,2-dichloroethenyl)-2,2-dimethylcyclohexyl) propanecarboxylate), fenothrin, prallethrin, profluthrin, protrifenbute, pyrethrin I and II, resmethrin, silafluofen, tefluthrin, tetramethrin, tralomethrin, transfluthrin, valerate, and their enantiomers. In another exemplary embodiment, the pyrethroid may be bifenthrin, cypermethrin, deltamethrin, etofenprox, and permethrin, or combinations thereof.

[0027]

[0035] In one embodiment, the organic co-biocide may include a neonicotinoid. For example, neonicotinoids include, but are not limited to, acetamiprid ((1E)-N-[(6-chloro-3-pyridinyl)methyl]-N'-cyano-N-methylethanimidamide), clothianidin ((E)-1-[(2-chlorothiazol-5-yl)methyl]-3-methyl-2-nitroguanidine), dinotefuran (N-methyl-N'-nitro-N"-[(tetrahydro-3-furanyl)methyl]guanidine), imidacloprid ((2E)-1-[(6-chloro-3-pyridinyl)methyl]-N-nitro-2-imidazolidinimine ... These include daclothiz, nitenpyram, nithiazine, paichongding, thiacloprid ((Z)-[3-[(6-chloro-3-pyridinyl)methyl]-2-thiazolidinylidene]cyanamide, and thiamethoxam (3-[(2-chloro-5-thiazolyl)methyl]tetrahydro-5-methyl-N-nitro-4H-1,3,5-oxadiazin-4-imine). In one embodiment, the neonicotinoid may be acetamiprid, clothianidin, dinotefuran, imidacloprid, thiacloprid and thiamethoxam, or a combination thereof.

[0028]

[0036] In one embodiment, the organic co-biocide may comprise a halogenated carbamate, such as, but not limited to, 3-iodo-2-propynyl butyl carbamate (IPBC), 3-iodo-2-propynyl hexyl carbamate (IPHC), 3-iodo-2-propynyl cyclohexyl carbamate (IPCC), 3-iodo-2-propynyl phenyl carbamate (IPPhC), 3-iodo-2-propynyl benzyl carbamate (IP Benzyl C), 3-iodo-2-propynyl propyl carbamate (IPPC), 4-iodo-3-butynyl propyl carbamate (IBPC), 3-iodo-2-propynyl-4-chlorophenyl carbamate (IPCI PhC), 3-iodo-2-propynyl-4-chlorobutyl carbamate (IPCI BC), and mixtures thereof. In one embodiment, the halogenated carbamate can be 3-iodo-2-propynyl butyl carbamate (IPBC).

[0029]

[0037] In one embodiment, the organic co-biocide may include an SDHI, including, but not limited to, flutolanil, isofetamide, fluopyram, fluxapyroxad, penthiopyrad, boscalid, fenfuram, carboxin, thifluzamide, benzovindiflupyr, bixafen, furametpyr, isopyrazam, penflufen, penthiopyrad, sedaxane, and mixtures thereof.

[0030]

[0038] In one embodiment, the organic co-biocide may include a quaternary ammonium salt (quat), such as, but not limited to, didecyldimethylammonium chloride, didecyldimethylammonium carbonate, dimethylbenzylammonium chloride, and didecylmethylpoly(oxyethyl)ammonium propionate, and mixtures thereof.

[0031]

[0039] In one embodiment, the organic co-biocide may include an azole, such as, but not limited to, clotrimazole, imazalil, oxpoconazole, prochloraz, pefurazoate, triflumizole, triforine, buthiobate, pyrifenox, fenarimol, nuarimol, triarimol, azaconazole, bitertanol, bromuconazole, sibroconazole (α-(4-chlorophenyl)-α-(1-cyclopropylethyl)-1H-1,2,4-triazole-1-ethanol), diclobutrazol, diphenaz ... Noconazole, diniconazole, diniconazole-M, epoxiconazole (rel-1-[[(2R,3S)-3-(2-chlorophenyl)-2-(4-fluorophenyl)-2-oxiranyl]methyl]-1H-1,2,4-triazole), etaconazole, fenbuconazole, fluquinconazole, flusilazole, flutriafol, (α-butyl-α-(2,4-dichlorophenyl)-1H-1,2,4-triazole-1-ethanol), imibenconazole , ipconazole, ipfentrifluconazole, mefentrifluconazole, metconazole, myclobutanil, penconazole (1-[2-(2,4-dichlorophenyl)pentyl]-1H-1,2,4-triazole), propiconazole (1-[[2-(2,4-dichlorophenyl)-4-propyl-1,3-dioxolan-2-yl]methyl]-1H-1,2,4-triazole), prothioconazole, quinconazole, simeconazole, tebuconazole (α-[2-(

[0046] Examples of such antibacterial agents include tetraconazole, triadimefon (1-(4-chlorophenoxy)-3,3-dimethyl-1-(1H-1,2,4-triazol-1-yl)-2-butanone), triadimenol (β-(4-chlorophenoxy)-α-(1,1-dimethylethyl)-1H-1,2,4-triazol-1-ethanol), triticonazole, and uniconazole.In one embodiment, the azole may be sibroconazole, epoxiconazole, penconazole, propiconazole, tebuconazole, triadimefon, triadimenol, or a combination thereof.

[0032]

[0040] According to the present disclosure, the one or more biocides may have an average particle size of from about 0.01 μm to about 25 μm, such as from about 0.1 μm to about 10 μm, such as from about 0.3 μm to about 8 μm, or any range therebetween.

[0033]

[0041] The at least one biocide may be present at about 0.01% or more by weight of the oily preservative and at about 10% or less by weight of the oily preservative, such as from about 0.05% to about 7.5% by weight, such as from about 0.5% to about 5% by weight, such as from about 1% to about 3.5% by weight, or any range therebetween.

[0034]

[0042] According to the present disclosure, the ratio of Cu (wt %) to co-biocide (wt %) in the oil-based preservative is from about 100:1 to about 1:100, such as from about 50:1 to about 1:1, such as from about 20:1 to about 1:1, or any range therebetween.

[0035]

[0043] According to the present disclosure, the oil-based preservative is present in the treatment chamber at a temperature of about 40°C to about 110°C, such as about 45°C to about 90°C, such as about 50°C to about 75°C, such as about 55°C to about 65°C, or any range therebetween. Advantageously, the wood product may be treated with the oil-based preservative at a temperature below about 90°C, such as below about 85°C, such as below about 80°C, such as below about 75°C, such as below about 70°C, such as below about 65°C, such as below about 60°C, such as below about 55°C, such as below about 50°C, such as below about 45°C.

[0036]

[0044] According to the present disclosure, the method disclosed herein includes impregnating a wood product with an oil-based preservative. Standard vacuum and / or pressure methods can be used to impregnate the wood. Standard processes are defined as described in New Zealand Timber Authority Specifications 1986, P2 Rueping (Empty Cell Process), P4 the Bethell Process, P5 the Lowry Process, and P9 the Alternating Pressure Method. In one embodiment, the treatment chamber containing the wood product and the oil-based preservative is pressurized to impregnate the wood product with the oil-based preservative. By immersing the wood product in the pressurized treatment chamber containing the oil-based preservative, the oil-based preservative becomes homogeneously impregnated on the surface of the wood product, rather than being merely applied on the surface or penetrating only a portion or unevenly into the wood product. The pressure applied to the treatment chamber to allow the oil-based preservative to penetrate the wood product may be from about 0.5 bar to about 12 bar, such as about 2 bar, such as about 3 bar, such as about 4 bar, such as about 5 bar, such as about 6 bar, such as about 7 bar, such as about 8 bar, such as about 9 bar, such as about 10 bar, such as about 11 bar. It is understood that the exact pressure value may depend on the size of the wood product and can be easily adapted by a person skilled in the art. According to the present disclosure, the treatment chamber is pressurized for about 5 minutes or more, such as about 30 minutes or more, such as about 60 minutes or more, such as about 120 minutes or more, such as about 180 minutes or more, such as about 240 minutes or more, to impregnate the wood product with the oil-based preservative. In one embodiment, the treatment chamber is pressurized for 300 minutes or less, such as about 200 minutes or less, such as about 150 minutes or less, such as about 100 minutes or less, such as about 60 minutes or less, to impregnate the wood product with the oil-based preservative.

[0037]

[0045] In one embodiment, the temperature of the oily preservative is about 110° C. or less, such as about 90° C. or less, such as about 85° C. or less, such as about 80° C. or less, such as about 75° C. or less, such as about 70° C. or less, such as about 65° C. or less, such as about 60° C. or less, such as about 55° C. or less, such as about 50° C. or less, such as about 45° C. In one embodiment, the temperature of the oily preservative is about 40° C. or more, such as about 50° C. or more, such as about 60° C. or more, such as about 70° C. or more, such as about 80° C. or less, such as about 90° C. or less, when the wood product is impregnated with the oily preservative.

[0038]

[0046] After impregnation of the wood product, the pressure in the treatment chamber is released to atmospheric pressure. This is followed by an intermediate drying stage. In one embodiment, the intermediate drying stage may include incubating the impregnated wood product in the treatment chamber immersed in the oil-based preservative at atmospheric pressure for about 30 minutes to about 180 minutes, such as about 60 minutes to about 120 minutes, or any range therebetween. In another exemplary embodiment, the intermediate drying stage may include at least partially evacuating the oil-based preservative from the treatment chamber and applying a vacuum in the treatment chamber. During the intermediate drying stage, after about 30 minutes of partial evacuation of the oil-based preservative, a gentle vacuum may be applied in the treatment chamber initially at about minus 0.5 (-0.5) bar. After the gentle vacuum, the vacuum pressure may be increased to about minus 0.85 (-0.85) bar for about 30 minutes to about 60 minutes. After the intermediate drying stage, the oil-based preservative may be transferred from the treatment chamber to a storage or separation tank. In one embodiment, the oil-based preservative may be evacuated from the treatment chamber. It will be appreciated that in certain exemplary embodiments, two or more of the steps including incubating, at least partially draining, and vacuum cycling the impregnated wood product described above may be performed during the intermediate drying stage.

[0039]

[0047] According to an exemplary embodiment of the present disclosure, once the oil-based preservative is drained, the wood product can be subjected to a final negative pressure treatment. In one embodiment, a final vacuum is applied in the treatment chamber to draw excess oil / water / preservative from the wood product impregnated with the oil-based preservative. The pressure applied during the negative pressure treatment may be less than about 3 bar, such as less than 2 bar, such as less than 1 bar. For example, the pressure applied during the negative pressure treatment may range from -0.1 bar to -1 bar. In one exemplary embodiment, the pressure applied during the negative pressure treatment may be about minus 0.5 (-0.5) bar. In another exemplary embodiment, the pressure applied during the negative pressure treatment may be about minus 0.8 (-0.8) bar. Applying negative pressure to the treatment chamber is useful to ensure that the wood product is drip-free and can be successfully removed from the treatment chamber if necessary. According to the present disclosure, a vacuum is applied in the treatment chamber for 30 minutes or more, such as about 60 minutes or more, such as about 120 minutes or more, such as about 180 minutes or more, such as about 240 minutes or more, such as about 5 hours or more, such as about 12 hours or more, such as about 24 hours or more, to remove water from the wood product impregnated with the oil-based preservative.

[0040]

[0048] Advantageously, the method disclosed herein results in a wood product having a dry to the touch, non-bleeding surface immediately after treatment. Surprisingly, the method disclosed herein provides a fast and efficient drying process for oil-based wood products.

[0041]

[0049] The wood products treated according to the present disclosure can include softwoods (e.g., fire-resistant and non-fire-resistant) and hardwoods.For example, the wood products can include one or more of utility poles, fence posts, and railroad ties.In one embodiment, the wood products are products formed from one or more of pine, spruce, cedar, fir, hemlock, oak, maple, cherry, eucalyptus, poplar, beech, and aspen.

[0042]

[0050] The foregoing description is exemplary in nature and is in no way intended to limit the scope, applicability, or arrangement of the present disclosure. Various changes to the described embodiments may be made in the function and arrangement of elements described herein without departing from the scope of the disclosure.

[0043]

[0051] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0052] As used in this application and in the claims, the singular forms "a," "an," and "the" include the plural forms unless the context clearly dictates otherwise. Additionally, the term "including" means "including." The methods and compositions of the present disclosure may include, consist of, or consist essentially of any additional or optional ingredients, components, or limitations described herein or otherwise useful in biocidal compositions, in addition to the essential elements and limitations of the embodiments described herein, including their components.

[0044]

[0053] Unless otherwise specified, all numbers expressing properties such as amounts, molecular weights, percentages of ingredients, etc., are understood to be modified by the term "about" when used in the specification or claims. Thus, unless otherwise specified, implicitly or explicitly, the numerical parameters recited are approximations that may depend on the desired properties sought and / or the limits of detection under standard test conditions / methods. In cases where the embodiments are directly and explicitly distinguished from the prior art discussed, the numbers of the embodiments are not approximations unless the word "about" is recited.

[0045]

[0054] "Optional" or "optionally," as used herein, means that the subsequently described material, event, or circumstance may be present or occur, or may be absent or not occur, and that the description includes instances in which the material, event, or circumstance is present or occurs as well as instances in which it is absent or does not occur. "w / w%" and "% by weight," as used herein, means the percentage by weight of another component or the total weight in a composition.

[0046]

[0055] The term "about" is intended to mean approximately, in the region of, approximately, or in the vicinity of. When the term "about" is used in conjunction with a numerical range, it modifies that range by extending the boundaries above and below the stated numerical values. Unless otherwise specified, the numerical parameters set forth in the specification and appended claims should be understood to be approximations. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, the numerical parameters should be read in light of the number of reported significant digits and the application of ordinary rounding techniques.

[0047]

[0056] The term "substantially free", when used to describe the amount of a substance in a material, is not limited to total or complete absence, and may correspond to the absence of any obvious or detectable amount of the recited substance in the material. Thus, for example, a material is said to be "substantially free" of a substance if the amount of the substance in the material is less than the precision of the industry-accepted equipment or test for measuring the amount of the substance in the material. In certain exemplary embodiments, a material can be "substantially free" of a substance if the amount of the substance in the material is less than 10%, less than 9%, less than 8%, less than 7%, less than 6%, less than 5%, less than 4%, less than 3%, less than 2%, less than 1%, less than 0.5%, or less than 0.1% based on the weight of the material.

[0048]

[0057] The terms "first," "second," and "third," as used herein, can be used interchangeably to distinguish one component from another, and are not intended to imply any placement or importance of the individual components.

[0049]

[0058] Herein, and throughout the specification and claims, range limitations may be combined or substituted, and such ranges are specified and include all subranges contained therein unless the context or language indicates otherwise. For example, all ranges disclosed herein are inclusive of the limits, and the limits are independently combinable with each other.

[0050]

[0059] The term "D50" or "D50 particle size", as used herein, refers to the volume median particle size, where 50% of the particles in a sample volume have a size below that range or value.

[0051]

[0060] Similarly, the term "D95" or "D95 particle size" as used herein refers to the value below which 95% of the particles in a volume of a sample have a size in that range or value.

[0061] As used herein, the term "particle size" refers to the median particle size D50 unless otherwise specified. Particle size can be measured using a laser scattering particle size analyzer, such as a HOLIBA LA910 particle sizer.

[0052]

[0062] The terms "median particle size" and "average particle size" and D50 are used interchangeably herein.

[0063] As used herein, the term "micronized" means having a median particle size (D50) in the range of 0.01 to 25 micrometers.

[0053]

[0064] This written description uses examples to disclose the invention, including the best mode, and also enables any person skilled in the art to practice the disclosure, including making and using any device or system, and performing any incorporated methods. The patentable scope of the disclosure is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include elements that are no different from the literal language of the claims, or if they include equivalent elements that are not substantially different from the literal language of the claims.

[0054]

[0065] Moreover, certain aspects of the present disclosure may be better understood from the following examples, which are intended to be non-limiting and exemplary in nature, and it will be understood that the compositions described in the examples may be substantially free of any material not expressly described. EXAMPLES

[0055] Example 1

[0066] Pine poles were treated using the standard Rueping process without the "drying" step (Figure 1). In Example 1, the temperature of the oil (i.e., Tanasote™) was 60°C. Upon removal, the treated poles had an oily surface residue and some leaching from the pole.

[0056]

[0067] Similar pillars were treated using the same Rueping process except that some of the oil was removed from the autoclave, then vacuum was applied as the "drying" step described herein, after which the majority of the preservative was drained and a final vacuum was applied. The pillars were removed and showed a dry surface appearance with minimal subsequent bleed-through (Figure 2). The pillars were dry to the touch and observed to have no bleed-through after treatment.

[0057] Example 2

[0068] A total of 354 notched pine ties (12 packs) were treated with Tanasote™ S40 to measure the noise reduction coefficient (NRC) over three charges. The treatment cycle for all three charges was a Rueping cycle with an intermediate drying stage (iDP) at 65° C. The cycle process was as follows:

[0058] [Table 1]

[0059]

[0069] The treated wood was removed from the treatment chamber, was dry to the touch, and showed no oozing or oiling during the treatment for two weeks after treatment.

[0060] Example 3

[0070] Four packs of Octowood pine poles were subjected to copper and oil treatments at a large Tanasote plant. Two of the four packs were kiln dried and the other two were air dried. Pieces from all four packs were subjected to various treatments using Bethel, Rueping, and modified Rueping cycles.

[0061]

[0071] In this example, the Bethel process left the pillars dry to the touch but overtreated (e.g., weighing more than twice the target loading of preservative) (>200-300 kg / m 3 In contrast, the Rueping process has a target loading of approximately 100 kg / m 3), but the posts were wet (e.g., free / residual oil on the surface) when they were removed from the treatment vessel and the product continued to leach Tanasote from the treated wood for many weeks after treatment, especially when exposed to warmer temperatures (i.e., when placed in direct sunlight). It is believed that the leaching is due to the initial air pressure applied, which expands as the post warms, pushing the Tanasote out.

[0062]

[0072] Therefore, the Reuping treated octowood pillars were immersed in an expansion bath at atmospheric pressure at 50° C. or 75° C. during the "drying stage" to reduce leaching from the surface of the octowood pillars.

[0063]

[0073] Each post was cut into two equal pieces (35 cm long) after removing the end grain. One piece from each article was immersed in Nytex 801 at 50°C. Once the oil temperature reached 50°C, the pieces were removed after 1, 2, and 3 hours. Once removed from the expansion bath, each piece was placed upright for 2 hours to allow all excess surface oil to drain from the wood. They were then patted dry, weighed, and photographed. Each bath was repeated with a second set of expansion baths.

[0064] [Table 2]

[0065]

[0074] All pieces at 50°C gained a small amount of weight regardless of the length of time they were in the expansion bath, suggesting that either a small amount of Nytex 801 penetration at the end grain or absorption at the wood surface during the expansion bath occurred. In contrast, all pieces exposed to the 75°C expansion bath lost a small amount of weight overall, suggesting that Tanasote™ was released from the wood.

[0066]

[0075] Photographs of the columns before and after the "drying" stage of the expansion bath show that in some cases the wood lightened in color, especially the pieces that had been in the 75°C bath (i.e., 2-129B, 4-103B and 4-104B) (Table 2).

[0067] [Table 3]

[0068]

[0076] For Set 2, very similar results were observed to those observed for Set 1. The 50°C articles showed a slight increase in mass compared to the 75°C articles which showed a slight decrease in mass. Again, this suggests that increasing the temperature above the treatment temperature leads to the release of some of the Tanasote from the wood.

[0069]

[0077] Photographs of the pillars before and after the expansion bath showed similar results to Set 1, with some appearing brighter after the expansion bath (i.e., 3-122B) (Table 3). Example 4

[0078] Surface wet wicking evaluation was performed on each column of Example 3 by placing a section of the white roll on each piece of wood for 72 hours. They were photographed again before being placed outside for continued visual evaluation. This was repeated for the matched pieces in a second bath, which began at 50°C and increased in temperature to 75°C before the time began. Of note, some bubbling from the wood was observed when heated at both 50°C and 75°C.

[0070] [Table 4]

[0071] [Table 5]

[0072]

[0079] All pillars that did not undergo an expansion bath drying step showed much more oozing on the white roll compared to the kiln dried ones, especially those from Pack 2.

[0080] Where the control showed greater than 10% wicking, each article showed improvement regardless of time in the 75°C expansion bath, most notably in Pack 2 which showed more wicking at the start. Pieces going through the 50°C bath showed improvement compared to the control in pieces from Pack 2, but comparable or worse performance compared to the control in Pack 4 (Table 5).

[0073] [Table 6]

[0074]

[0081] For Set 2, wicking ratings were compared to scraps of each article since larger pieces were not available for individual evaluation. Limited wood pieces were obtained by selection from those that had all gone through the same treatment process, had not gone through an expansion bath, had been recently treated, and had leaching. All pieces selected appeared wet and filled with Tanasote when they were selected.

[0075]

[0082] The control pieces from Set 2 showed even less wicking than Set 1 (Table 6). The 75°C expansion bath showed improved or equivalent performance compared to the control (where the control showed less than 10% wicking) in the wicking evaluation for each article. The 50°C bath showed equivalent performance compared to the control for pieces from Pack 2 and a range of results for the Pack 3 pieces (Table 6).

[0076]

[0083] In both sets of expansion baths, the wood pieces at 50°C gained weight, which is likely due to penetration at the end grain. All pieces at 75°C lost a small amount of weight overall, suggesting that Tanasote was being released from the wood.

[0077]

[0084] Several pieces exposed to the 75° C. bath were visibly lighter in color after the expansion bath compared to the start, most notably pieces 2-129B, 4-103B, 4-104B and 3-122B.

[0078]

[0085] For each article in Set 1 where the control showed greater than 10% wicking on the white roll, an improvement was seen in the 75° C. bath, most notably in Pack 2, which originally showed more wicking. For articles that showed less than 10% wicking in the control, the performance of the pieces in the 75° C. bath remained the same. The 50° C. bath showed an improvement for pieces from Pack 2, which were considered kiln dried, but showed comparable or worse performance in Pack 4, which were considered air dried.

[0079]

[0086] The wicking evaluation of Set 2 had comparable results. Whereas the control showed 10% more wicking, each article at 75°C improved in wicking evaluation regardless of time. The 50°C bath showed no improvement in wicking evaluation compared to the control, with five of the six pieces remaining the same and one performing worse.

[0080]

[0087] Overall, both sets of expansion baths showed improvements at 75°C compared to the control at 1, 2, and 3 hours. The 50°C expansion bath showed some improvement for some articles, but was not consistent for all pieces from each pack or for a particular length of time. Based on these data, it is recommended to use an expansion bath at 75°C instead of 50°C.

[0081]

[0088] These and other modifications and variations to the present invention may be practiced by those skilled in the art without departing from the spirit and scope of the invention as more particularly described in the appended claims. In addition, it should be understood that forms of the various embodiments may be interchanged both in whole or in part. Moreover, those skilled in the art will appreciate that the foregoing description is by way of example only and is not intended to limit the invention so further described in such appended claims.

Claims

1. 1. A method for treating a wood product, comprising: injecting an oil-based preservative into a treatment chamber containing the wood product; pressurizing the treatment chamber containing the wood product and the oil-based preservative to impregnate the wood product with the oil-based preservative, wherein the pressure in the treatment chamber is from about 0.5 bar to about 12 bar; releasing the pressure in the processing chamber to atmospheric pressure; performing an intermediate drying stage, the intermediate drying stage comprising: Incubating wood products impregnated with oil-based preservatives at temperatures not exceeding 90 degrees Celsius; at least partially draining the oil-based preservative from the processing chamber; and / or applying a vacuum within the processing chamber; a step of: discharging the oily preservative from the processing chamber after performing the intermediate drying step; and applying a vacuum within the treatment chamber during the drying stage to remove excess preservative from the surface of the impregnated wood product. A method comprising:

2. 10. The method of claim 1, wherein during the intermediate drying stage, about 5% to about 30% of the oil-based preservative is expelled from the processing chamber.

3. 10. The method of claim 1, wherein the wood products include one or more of a utility pole, a fence post, and a railroad tie.

4. 3. The method of claim 1 or 2, wherein the wood product comprises a product formed from one or more of pine, spruce, cedar, fir, hemlock, oak, maple, cherry, eucalyptus, poplar, beech, and aspen.

5. 3. The method of claim 1 or 2, wherein the temperature of the oil-based preservative is 40 degrees Celsius or higher when the wood product is impregnated with the oil-based preservative.

6. 6. The method of claim 5, wherein the temperature of the oil-based preservative is about 60 degrees Celsius when the wood product is impregnated with the oil-based preservative.

7. 3. The method according to claim 1 or 2, wherein in the drying step a vacuum of up to 0.5 bar is applied to remove excess preservative from the surface of the impregnated wood product.

8. 3. The method of claim 1 or 2, wherein the treatment chamber is pressurized for at least 5 minutes and at most 300 minutes to impregnate the wood product with the oil-based preservative.

9. 3. The method of claim 1 or 2, wherein after the oil-based preservative has been evacuated from the treatment chamber, the vacuum is applied within the treatment chamber for 30 minutes or more to remove excess preservative from the surface of the impregnated wood product.

10. 3. The method of claim 1 or 2, further comprising the step of removing the oil-based preservative-impregnated wood product from the treatment chamber, wherein the temperature of the oil-based preservative-impregnated wood product from the treatment chamber is 60 degrees Celsius or less when the oil-based preservative-impregnated wood product is removed from the treatment chamber.

11. 3. The method of claim 1 or 2, wherein the oil-based preservative comprises copper and at least one organic co-biocide.

12. 11. The method of claim 10, wherein the copper is present in the oily preservative at about 1% or more by weight of the oily preservative and at about 10% or less by weight of the oily preservative.

13. 12. The method of claim 11, wherein the at least one organic co-biocide is present at about 0.01% by weight or more of the oily preservative and at about 10% by weight or less of the oily preservative.

14. 12. The method of claim 11, wherein the at least one organic co-biocide comprises one or more of an isothiazolone, a pyrethroid, a neonicotinoid, a halogenated carbamate, a quaternary ammonium salt, a succinate dehydrogenase inhibitor (SDHI), and an azole.

15. 10. The method of claim 1, wherein the impregnated wood product is incubated with the oil-based preservative during the intermediate drying stage for 180 minutes or less.

16. 10. The method of claim 1, wherein the impregnated wood product is incubated with the oil-based preservative during the intermediate drying stage for 60 minutes or less.

17. The method of claim 1 or 2, further comprising applying a second vacuum after removing excess preservative from the surface of the impregnated wood product.

18. 3. A wood product treated according to the method of claim 1 or 2.

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