Patent Application
20070131136
This invention relates to a composition and method for both coloring and, optionally, preserving cellulosic products, such as wood, to improve their outdoor weathering properties and their resistance to rot- and decay-causing organisms or environmental agents. More particularly, the invention relates to a composition and method whereby coloring and preserving of wood may be accomplished in a single application step, or sequentially, in two separate application steps, which may be performed in either order.
Wood which is both colored and preserved is used extensively in the construction industry in applications including siding, fencing, and decking. It has long been desirable to produce wood products that have an aesthetically pleasing appearance and good outdoor weathering properties, and yet have resistance to attack by wood destroying agencies such as fungi, bacteria and insects.
Untreated wood, when exposed to an outdoor environment, is subject to bio-deterioration due to attack by decay fungi and insects. In addition, untreated wood is subject to photo-degradation which will cause yellowing, fading, graying and, over time, a darkening of the wood surface.
Traditionally, wood preservative solutions used by wood preservation industry to impart resistance to fungal and insect attack contain metals or metal complexes. Examples are chromated copper arsenate (CCA), alkaline copper quaternary ammonium compounds (ACQ) and others, such as those described in American Wood Preservers' Association Standards-2005. These preservative systems not only provide decay and termite resistance, but also provide protection against photo-degradation due to the presence of metal or metal complexes which can act as absorbers and/or blockers of ultraviolet radiation. Unfortunately, many of the metal-based preservatives impart an undesirable color to the wood.
Thus, the wood preservation industry is increasingly interested in non-traditional preservatives, such as organic preservatives or non-metal based preservatives. However, such preservatives generally weather poorly upon exposure to sunlight. In fact, wood which has been treated with these preservatives can weather as poorly as wood which has not undergone treatment.
Thus colorants have been used in conjunction with preservatives in an attempt to improve weathering properties of preserved wood.
One technique currently used to color wood is to paint the surface of the wood with oil or water based pigment paint coating. However, paint often will not adhere to preservative-treated wood, resulting in blistering or flaking of the coating in a short period of time.
Additionally, a critical failure of this and other coating methods is that they provide surface coloration which may wear away, or lose color due to dent or scratches or other physical damage to the surface, requiring additional treatment or servicing if long term weathering is desired.
Another technique currently used to color wood is the addition of water soluble dyes to the preservative solution thereby imparting color to treated wood products. However, water soluble dyes, such as acid dyes or cationic dyes, generally have poor lightfastness, generally fading or decomposing upon exposure to sunlight, particularly ultra violet (UV) wavelengths.
In view of the many shortcomings of the current methods of coloring and preserving wood, it is desirable to have a coloring and preserving system that provides an aesthetically pleasing appearance, long-term weathering performance, and resistance to biodeterioration. It is also desirable to have a coloring and preserving process which can, if desired, be completed in a single application step.
Provided are wood colorant compositions that can be used with inorganic and organic wood preservatives. The colorant compositions comprise dispersions of inorganic and/or organic pigments in the form of micronized particles. The composition optionally additionally comprises inorganic and/or organic biocides, which may be present as dispersions, emulsions or in solution.
The compositions of the present invention can be used to color wood or in additional embodiments, to simultaneously color and preserve wood. In the art, “wood preservatives” and “biocides” are sometimes identified with inorganic (metal or metal salt) or organic compounds, respectively. However, herein, the terms “preservative” and “biocide” are used interchangeably to refer to both organic and inorganic compounds.
In one embodiment, the composition comprises a micronized inorganic pigment. In another embodiment, the composition comprises a micronized organic pigment. In yet another embodiment, the composition comprises one or more micronized inorganic and/or organic pigments and a micronized biocide. In further embodiments, the composition comprises one or more micronized inorganic and/or organic pigments and one or more inorganic and/or organic biocides. Dyes including acid dyes, basic dyes and direct dyes can optionally be added to the composition to further enhance the aesthetic appearance of the wood.
Also provided is a method for coloring and preserving wood simultaneously.
Also provided is a method for coloring and preserving wood comprising the step of impregnating wood with the compositions of the above embodiments.
Also provided is a method for coloring and preserving wood comprising the steps of:
Also provided is a method for imparting lightfast, uniform color to wood.
When wood is treated with the composition of the present invention, the pigment, and the preservative, if present, are carried beneath the surface of the wood, imparting long lasting color to the wood and preserving it from biological degradation.
Also provided is a method of impregnating color beneath the surface of wood to provide for long term application.
Also provided is a method for imparting color to wood which improves the outdoor weathering properties of wood.
Pigment formulations have been used to coat and paint wood. However, the present invention pertains to the coloring, and, optionally preserving of wood by impregnation with pigment, and optionally biocides, giving a preserved product having lightfast, non-flaking color. Impregnation into wood imparts to the wood excellent UV resistance, and thus, excellent weathering characteristics. Impregnation of colorants into wood also simplifies the coloring process and improves the efficiency and throughput of coloring and preserving wood compared to traditional painting and/or staining processes.
The pigment dispersion comprises micronized inorganic pigments, such as, for example, iron oxides including red, yellow, black and brown iron oxides, carbon black, cupric oxide, cuprous oxide, zinc oxides, titanium oxides and chrome oxides; and/or micronized organic pigments.
Also provided is a method for the treatment of wood or wood product with the compositions of the present invention
The present invention provides compositions and methods for coloring, and optionally, preserving wood and wood products. The present invention also provides compositions and methods for coloring and preserving wood products simultaneously. The composition comprises a pigment dispersion, and optionally an organic or inorganic biocide/wood preservative. In some embodiments of the present invention, the pigments are red iron oxide, yellow iron oxide, black iron oxide, brown iron oxide, zinc oxide, titanium oxide, cuprous and cupric oxide, or carbon black. In additional embodiments, the composition additionally comprises metal compounds or metal complexes as a preservative, preferably copper compounds or copper complexes including copper carbonate, copper hydroxide, oxine copper, cuprous oxide and cupric oxide, optionally in a micronized form. It should be noted that pigment compounds may also have biocidal ability as well. In another embodiment, the preservative composition additionally comprises one or more organic or metal free biocides, preferably quaternary ammonium compounds, particularly didecyldimethylammonium chloride, didecyldimethylammonium carbonate/bicarbonate, alkyldimethylbenzylammonium chloride, alkyldimethylbenzylammonium carbonate/bicarbonate, didodecyldimethylammonium chloride, didodecyldimethylammonium carbonate/bicarbonate, didodecyldimethylammonium propionate, N,N-didecyl-N-methyl-poly(oxyethyl)ammonium propionate; imidazoles or triazoles, for example, tebuconazole, cyproconazole, propiconazole, hexaconazole, 1-[[2-(2,4-dichlorophenyl)-1,3-dioxolan-2-yl]methyl]-1H-1,2,4-triazole; cis-trans-3-chloro-4-[4-methyl-(2-(1H-1,2,4-triazol-1-ylmethyl)-1,3-dioxolan-2-yl]phenyl 4-chlorophenyl ether; (RS)-2-(4-fluorophenyl)-1-(1H-1,2,4-triazol-1-yl)-3-(trimethylsilyl)propan-2-ol; 2-(2,4-difluorophenyl)-(1H-1,2,4-triazole-1-yl)-3-trimethylsilyl-2-propanol; pyrethroids, such as, for example, bifenthrin, permethrin, cypermethrin; isothiazolone compounds, particularly 4,5-Dichloro-2-n-octyl-3(2H)-isothiazolone (RH-287), methylisothiazolinone, chloromethylisothiazolinone, 1,2-benzisothiazolin-3- one, 2-octyl-3-isothiazolone; Amine oxides, particularly Barlox 10, Barlox 12, Barlox 14 and Barlox 16; imidachloprid; chlorpyrifos; cyfluthrin; fipronil, chlorothalonil or combinations of the foregoing.
The present invention pertains to the use of pigment dispersions to color wood. The present invention also pertains to the use of pigment dispersions, in combination with organic and/or inorganic biocides, to color and preserve wood. The difference between pigments and dyes is generally understood by one of skill in the art. Pigments are generally more lightfast and have a greater resistance to UV degradation than dyes. Another difference is that pigments generally have little or no solubility in the medium in which they are applied. Thus, if the composition of the present invention is applied as an aqueous dispersion, the pigment in the composition is generally one which has little or no solubility in water. The present invention is primarily directed toward applications which include the use of pigments in an aqueous carrier. However, pigment dispersions in other carriers, such as polar or nonpolar organic carriers, including oil carriers, are within the ambit of the invention. Non-limiting examples of non-aqueous carriers which can be used are oil carriers such as, for example, mineral oil, linseed oil, soybean oil, AWPA p-9 oil, and other known in the art. In general, the term “pigment” as used herein refers to a wood coloring compound which, when applied in a carrier, has a solubility of less than 5g per 100 grams carrier in the chosen carrier, and preferably less than 1.0 g, 0.5 g, 0.1 g or 0.01 g per 100 grams of carrier (at 25° C.). Furthermore, the coloring compound also should have a water solubility of less than 5 g per 100 grams of water at 25° C., and preferably less than 1.0, 0.5, 0.1 or 0.01 g per 100 g of water.
The pigments which can be used in the compositions of the present invention include inorganic and organic pigments. Inorganic pigments include metal compounds of metals such as iron, zinc, titanium, lead, chromium, copper, cadmium, calcium, zirconium, cobalt, magnesium, aluminum, nickel, and other transition metals. Carbon black is also an inorganic pigment, which can be used in the present invention.
Some non-limiting examples of suitable inorganic pigments include: iron oxides, including red iron oxides, yellow iron oxides, black iron oxides and brown iron oxides; carbon black, iron hydroxide, graphite, black micaceous iron oxide aluminum flake pigments, pearlescent pigments, calcium carbonate, calcium phosphate, calcium oxide, calcium hydroxide, bismuth oxide, bismuth hydroxide, bismuth carbonate, copper carbonate, copper hydroxide, basic copper carbonate, cupric oxide, cuprous oxide, silicon oxide, zinc carbonate, barium carbonate, barium hydroxide, strontium carbonate, zinc oxide, zinc phosphate, zinc chromate, barium chromate, chrome oxide, titanium dioxide, zinc sulfide and antimony oxide, lead chrome, and cadmium pigments.
Preferred inorganic pigments are carbon black; graphite; iron oxides, including yellow, red, black and brown iron oxides; zinc oxide; titanium oxide and aluminum-based pigments, such as, for example Al2O3 and Al(OH)3.
Non-limiting examples of organic pigments include Monoazo (arylide) pigments such as PY3, PY65, PY73, PY74, PY97 and PY98; Disazo (diarylide); Disazo condensation; Benzimidazolone; Beta Naphthol; Naphthol; metal-organic complexes; Isoindoline and Isoindolinone; Quinacridone; perylene; perinone; anthraquinone; diketo-pyrrolo pyrrole; dioxazine; triacrylcarbonium; the phthalocyanine pigments, such as cobalt phthalocyanine, copper phthalocyanine, copper semichloro- or monochlorophthalocyanine, copper phthalocyanine, metal-free phthalocyanine, copper polychlorophthalocyanine, phthalocyanine blue, etc.; organic azo compounds; organic nitro compounds; polycyclic compounds, such as phthalocyanine pigments, quinacridone pigments, perylene and perinone pigments; diketopyrrolo-pyrrole(DPP) pigments; thioindigo pigments; dioxazine pigments; quinophthalone pigments; triacrylcarbonium pigments, and Diaryl pyrrolopyroles, such as PR254.
Non-limiting examples of organic pigments which can be used in the present invention, grouped according to the color they produce (e.g. blues, blacks, greens, yellow, reds and browns), based on their color index include: Pigment Yellows (PY) 1, 11, 3, 12, 13, 14, 17, 81, 83, 65, 73, 74, 75, 97, 111, 120, 151, 154, 175, 181, 194, 93, 94, 95, 128, 166, 129, 153, 109, 110, 173, 139, 185, 138, 108, 24; Pigment Oranges (PO) 5, 36, 60, 62, 65, 68, 61, 38, 69, 31, 13, 34, 43, 51, 71, 73; Pigment Reds (PR) 3, 4, 171, 175, 176, 185, 208, 2, 5, 12, 23, 112, 146, 170, 48, 57, 60, 68, 144, 166, 214, 220, 221, 242, 122, 192, 202, 207, 209, 123, 149, 178, 179, 190, 224, 177, 168, 216, 226, 254, 255, 264, 270, 272; Pigment Violets (PV) 32, 19, 29, 23, 37; Pigment Browns 25, 23; Pigment Blacks 1, 31, 32, 20; Pigment Blues (PB)15, 15:1, 15:2, 15:3, 15:4, 15:6, 16, 60; and Pigment Greens (PG) 7, 36.
It is preferred that the dispersion particle size distributions (or emulsion droplet size distribution, if applicable) contain particles (or droplets) of micronized size. The term “micronized” as used herein means a particle size in the range of 0.001 to 25 microns.
It should be understood that “micronized” does not refer only to particles which have been produced by the finely dividing, such as by mechanical grinding through media mill, of materials which are in bulk or other form. Micronized particles can also be formed by other mechanical, chemical or physical methods, such as, for example, pulverization process, formation in solution or in situ, with or without a seeding agent, grinding or impinging jet. The term “particle size” refers to the largest axis of the particle. In the case of a generally spherical particle, the largest axis is the diameter.
The formulations of micronized inorganic and/or organic pigments can be obtained by grinding the pigments, optionally wetted or present as a dispersion, to the desired particle size using a grinding mill. Other fine particle dividing methods known in the art can also be used, such as high speed, high shear mixing or agitation. The resulting particulate additive can be mixed with an aqueous liquid carrier to form a solution of dispersed additive particles.
Optionally, the solution can comprise a thickener, such as, for example, a cellulose derivative, as is known in the art and/or resin binder, such as polyacrylic, polyurethane, and other known in the art.
The particles are preferably dispersed and stabilized in the presence of dispersant(s). Dispersants function in micronized particle systems by 1) replacing the air around the particle surface and thus wetting the particle; 2) breaking down and/or preventing formation of particle agglomerates; and 3) stabilizing ground/reduced particles and preventing flocculation during storage. Dispersants can be divided into classes, two of which are polymeric dispersants and conventional low molecular surfactant type of dispersants. Polymeric dispersants generally possess a structure with pigment-affinic groups and a polymer chain and stabilizes the pigment particles through steric hindrance, while surfactant type dispersants generally possesses a hydrophilic group and a hydrophobic group and it stabilizes pigment particles through electrostatic mechanism.
Pigment stabilization can be particularly important when using micronized particles in wood treating processes. It not only requires a stabilized particle during storage, but also requires that particles maintain stability during repetitive treatments in a commercial treating plant. During repetitive treating processes, pH change, wood extractives, wood sugars and contaminants from wood surface and dirt from air can all affect the function of dispersants and hence the dispersion particle stability. Many surfactant-type low molecular weight dispersants can provide particles with short-term stability; in addition, surfactant-type low molecular weight dispersants are more sensitive to treatment environmental variables, such as the wood extractives, wood sugars, water quality, and degree of shear experienced during treatment. As a result, surfactant type dispersants are generally not preferred for the current application in preparing pigment dispersions. The particles can become unstable during long-term storage and during treating process and result in agglomeration and aggregation into large particles. Such agglomerates can impede treatment and leave a sludge on the surface of treated wood.
We have surprisingly found that polymeric dispersants can not only provide long-term stability of pigment dispersion particles, but also impart a high degree of stability during repetitive treatment processes. Generally, the weight average molecular weight of the polymeric dispersants varies from a few thousand to 100,000 or even more.
Non-limiting examples of polymeric dispersant classes which can be used in the compositions of the present invention include acrylic copolymers, aqueous solution of copolymers with pigment affinity groups, polycarboxylate ether, modified polyacrylate or modified polyacrylate with groups of high pigment affinity, acrylic polymer emulsions, modified acrylic polymers, poly carboxylic acid polymers and their salts, modified poly carboxylic acid polymers and their salts, fatty acid modified polyester, aliphatic polyether or modified aliphatic polyether, solution of polycarboxylate ether, phosphate esters, phosphate ester modified polymers, polyglycol ethers or modified polyglycol ethers, polyetherphosphate, modified maleic anhydride/styrene copolymer, sodium polyacrylate, sodium polymethacrylate, lignin, modified lignin and the like; modified polyether or polyester with pigment affinic groups; fatty acid derivatives; urethane copolymer or modified urethane copolymer, polyetherphosphate, modified maleic anhydride/styrene copolymer, modified polycarboxylic acid or its derivatives, acrylic acid/maleic acid copolymer, polyvinyl pyrrolidone or modified polyvinyl pyrrolidone, sulfonates or sulfonate derivatives, polymeric alkoxylate or its derivatives, or modified lignin and the like. If desired, a stabilizer as is known in the art can be used. Other dispersants can be found in 2004 McCutcheon's Functional Materials (North American Edition).
We have found that polymeric dispersants, especially modified polycarboxylate ether, modified poly carboxylic acid polymers and their salts, solutions of polycarboxylate ethers; modified polyether or polyester with pigment affinic groups, perform well with inorganic pigment compounds, particularly iron oxides, in providing wetting, dispersing, storage stabilization and stability during treatment process. We have also found that polymeric dispersants, particularly modified maleic anhydride/styrene copolymer or acrylic acid/maleic acid copolymer, perform well with organic pigments in providing wetting, dispersing, storage stabilization and stability during repetitive treating process.
For inorganic pigments, such as iron oxides, the level of dispersant is preferably in the range of from about 0.1 to 180% of the weight of the pigment compounds, and in other embodiments, in the range of 1 to 80%, 5 to 60%, and 10 to 30%. For organic pigments, the level of dispersant is preferably in the range of from about 1 to 200% of the weight of the pigment compounds, and in other embodiments in the range of 5 to 100%, 10 to 80%, and 30 to 70%.
If desired, a wetting agent can be used in the preparation of the compositions of the present invention. The level of wetting agent is preferably in the range of from about 0.1 to 50% of the weight of the pigment, and in other embodiments in the range of 0.5 to 10%, and 0.5 to 5%.
The composition of the present invention can be a concentrate or a preparation which is ready to apply to wood. In general, the total pigment concentrate is in the range of from 1 wt % to 80 wt %, based on weight of the composition, and preferably in the range of from 5 to 70 wt %, and more preferably in the range of from 30 to 65 wt %.
In the composition of the present invention, it is preferable that the pigment dispersion be present in the treating liquid applied to wood in amounts in the range of from 0.005 to 50 wt % of the solution, with a preferred range of 0.01 to 20%, and a more preferred range of 0.05 to 10%, and an even more preferred range of 0.1 to 1.0%.
A preferred method of preparing the pigment particles is by grinding. An exemplary method involves the formation of a slurry comprising a dispersant, a carrier, and a powdered pigment having a particle size in the range of from 1 micron to 500 microns, and optionally, a defoamer. The slurry is transferred to a grinding mill which is prefilled with a grinding media having a size in the range of from 0.05 mm to 5 mm, and preferably between 0.1 and 1 mm. The media can be one or more of many commercially available types, including but not limited to steel shots, carbon steel shots, stannous steel shots, chrome steel shots, ceramic (for example, alumina-containing); zirconium-based, such as zirconia, zirconium silicate, zirconium oxide stabilized zirconia such as yttrium-stabilized zirconia and ceria-stabilized zirconia; stabilized magnesium oxide; stabilized aluminum oxide, etc. The medium preferably occupies 50% to 99% of the grinding chamber volume, with 75 to 95% preferred, and 80 to 90% more preferred. The bulk density of the grinding media is preferably in the range of from 0.5 kg/l to 10 kg/l, and more preferably in the range of from 2 to 5 kg/l. Agitation speed, which can vary with the size of the grinder, is generally in the range of from 1 to 5000 rpm, but can be higher or lower. Lab and commercial grinders generally run at different speeds. A set up which involves a transfer pump which repeatedly cycles the slurry between the mill and a storage tank during grinding is convenient. The transfer pump speed varies from 1 to 500 rpm, and the speeds for lab and commercial grinders can be different. During grinding, defoamer can be added if foaming is observed. During grinding, particle size distribution can be analyzed, and once particle size is within the desired specification, grinding is stopped.
In the compositions of the present invention, in some embodiments, it preferred that at least 98% of the particles (by weight) have a diameter less than 10 microns, less than 5 microns or less than 1 micron.
The penetration of the pigment dispersion formulation into the cellular structure of wood or other cellulose-based material is dependent upon particle size considerations. If the inorganic/organic pigments used in formulating the dispersion formulation disclosed herein have a particle size in excess of 25 microns, the particles may be filtered by the surface of the wood and thus may not be uniformly distributed within the cell and cell wall.
In addition to the pigment dispersions, the present invention may comprise an inorganic and/or organic biocide component. This component may be micronized, emulsified, or present in solution. The above particle size considerations apply to the total particulate content, whether the particles are pigments or other particulate composition components. Although it is desirable to prepare separate concentrates of micronized pigments and micronized biocides and combine them to make treating compositions in the treating plant, a blended concentrate of micronized pigments and, optionally, micronized biocides and treating compositions can be obtained by direct dilution.
Non-limiting examples of inorganic biocides include materials such as metal complexes and metal compounds, as well as alkaline metal complexes and other metal complexes. Suitable metals include copper, arsenic, zinc, silver, cadmium, nickel, bismuth, lead and chromium, with copper being preferred. Suitable metal compounds and complexes can be obtained as concentrates, such as copper oxides, copper carbonate, copper omadine, copper 8-hydroxyquinolate (oxine copper).
The metal compounds, such as copper compounds, can also be in micronized particulate form when used with pigment dispersion. The preparation of the micronized metal compounds and the particle size range and distribution are similar to those of micronized pigments.
In addition to or instead of metal compounds and/or metal complexes, the present invention can also comprise organic biocidal compounds.
Some non-limiting examples of organic biocides are listed as follows:
Aliphatic Nitrogen Fungicides
Preferred insecticides which can be mixed micronized metal formulations are:
Antibiotic Insecticides
Preferred bactericides include:
Preferred biocides include: azole compounds, such as tebuconazole; cyproconazole; propiconazole; hexaconazole, 1-[[2-(2,4-dichlorophenyl)-1,3-dioxolan-2-yl]methyl]-1H-1,2,4-triazole; cis-trans-3-chloro-4-[4-methyl-2-(1H-1,2,4-triazol-1-ylmethyl)-1,3-dioxolan-2-yl]phenyl 4-chlorophenyl ether; (RS)-2-(4-fluorophenyl)-1-(1H-1,2,4-triazol-1-yl)-3-(trimethylsilyl)propan-2-ol; 2-(2,4-difluorophenyl)-1-(1H-1,2,4-triazole-1-yl)-3-trimethylsilyl-2-propanol; isothiazolone compounds, such as methylisothiazolinone; chloromethylisothiazolinone; 4,5-Dichloro-2-n-octyl-3(2H)-isothiazolone; 1,2-benzisothiazolin-3-one; 2-octyl-3-isothiazolone; imidachloprid; fipronil; cyfluthrin; bifenthrin; permethrin; cypermethrin; and chlorpyrifos; iodopropynyl butylcarbamate (IPBC); chlorothalonil; 2-(thiocyanatomethylthio) benzothiazole; alkoxylated diamines and carbendazim.
Organic biocides also include quaternary ammonium compounds disclosed in the present invention have the following structures:
where R1, R2, R3, and R4 are independently selected from alkyl or aryl groups and X− selected from chloride, bromide, iodide, carbonate, bicarbonate, borate, carboxylate, hydroxide, sulfate, acetate, laurate, or any other anionic group.
Preferred quaternary ammonium compounds include didecyldimethylammonium chloride; didecyldimethylammonium carbonate/bicarbonate; alkyldimethylbenzylammonium chloride; alkyldimethylbenzylammonium carbonate/bicarbonate; didodecyldimethylammonium chloride; didodecyldimethylammonium carbonate/bicarbonate; didodecyldimethylammonium propionate; N,N-didecyl-N-methyl-poly(oxyethyl)ammonium propionate.
Without desiring to be bound by theory, penetration of the micronized dispersion formulation into wood takes place because particles migrate into or are taken up by tracheids in the wood.
Studies by Mercury-Porosimetry technique indicated that the overall diameter of the border pit chambers typically varies from a several microns up to thirty microns while, the diameter of the pit openings (via the microfibrils) typically varies from several hundredths of a micron to several microns.
The size of the particles used in the dispersion formulation disclosed herein can be micronized, i.e., with a long axis dimension between 0.001-25 microns. In another embodiment, the particle size is between 0.001-10 microns. In another embodiment, the particle size is between 0.01-5 microns. In yet another embodiment, the particle size is between 0.01 to 2 microns. If superior uniformity of penetration is desired, particle size of the additive used in the dispersion formulation disclosed herein should be between 0.05-1 microns.
It should be noted that the above does not exclude the presence of particles outside the stated ranges. However, particles which are too large can clog the wood, preventing it from taking in other particles. Thus particle size distributional parameters can affect the uniformity of particle distribution in the wood, as well as the leaching properties of treated wood. It is thus preferable to use particle size distributions which contain relatively few particle sizes outside the range of 0.001 to 25 microns. It is preferred that no more than 20 weight percent of the particles have diameters which are greater than 25 microns. Regardless of the foregoing recommendations, it is generally preferred that at least 60%, and more preferably, at least 80 wt % of the particles have a diameter in the range of 0.001 to 25 microns. In more preferred embodiments, greater than 85, 90, 95 or 99 wt percent particles are in the range of 0.001 to 25 microns. Depending on the degree of penetration desired, greater than 5, 10, 20 or 50 wt % of the particles can be less than 5, 1 or 0.5 microns.
For increased degree of penetration and uniformity of distribution, at least 50 wt % of the particles should have diameters which are less than 10 microns. More preferred are particle distributions which have at least 80, 90, 95, or 99 wt % of the particles with sizes of less than 10 microns. In an additional embodiment, at least 60 wt % of the particles should have diameters which are less than 1 micron. More preferred are particle distributions which have at least 80, 90, 95, or 99 wt % of the particles with sizes of less than 1 micron.
In order to further improve the weathering properties and the lightfastness of the pigment treated wood or further improve the adhesion of pigment particles to wood, a resin binder is often used in the composition. Examples of resin binders which can be used include polyurethane, polyester, polyvinyl alcohol, polyamide, epoxy, acrylic polymers, vinyl polymers (including polymers made from ethylenically unsaturated monomers such as polybutene), cellulosic derivatives, oligomers and natural polymers, can be either added to the pigment dispersion or added to the final treating composition. Examples of resin binders include:
In the composition of the present invention, the ratio of the resin content to the pigment solid content in the treating composition ranges from about 0.001:1 to about 1000:1, and preferably ranges from about 0.01:1 to about 10:1, and more preferably range from 0.05:1 to about 1:1.
In the present invention dyes can optionally be added to the pigment compositions or preservative composition or treating compositions to obtain the desirable color and enhance the color richness of the treated wood. Dyes can be basic dyes (or cationic dyes), acid dyes, direct dyes, azoic dyes, sulfur dyes, vat dyes, and reactive dyes. Preferred dyes are basic dyes.
Non-limiting examples of basic dyes are: derivatives of diphenylmethane; triphenylmethane or acridine; thiazine, oxazine, or azine dyes; xanthene basic dyes, basic dyes containing azo groups, and basic dyes containing a pendant cation, a delocalized charge, or a heterocylic ring which contains a quaternary nitrogen atom; 2-(((4-Methoxyphenyl)methylhydrazono) methyl)-1,3,3-trimethyl-3H-indolium methyl sulphate; 2-(2-(4-((2-Chloroethyl) methylamino)phenyl)vinyl)-1,3,3-trimethyl-3H-indolium chloride; 3,7-Bis(dimethylamino)phenothiazin-5-ium chloride; 7-(Dimethylamino)-6-nitro-3H-phenothiazin-3-ylidene)dimethylammonium chloride; Methanaminium N-[4-[[4-(dimethylamino)phenyl]phenylmethylene]-2,5-cyclohexadien-1-ylidene]-N-methyl-, chloride; 4-((4-aminophenyl)(4-imino-2,5-cyclohexadien-1-ylidene)methyl)-2-methyl-benzenamine; 4,4′-((4-imino-2,5-cyclohexadien-1-ylidene)methylene)dianiline monohydrochloride; 1,3-Benzenediamine, 4,4′-(1,3-phenylenebis(azo))bis-, dihydrochloride; 3-Methyl-2-((1-methyl-2-phenyl-1H-indol-3-yl)azo)thiazolium chloride; (2-((4-((2-Chloro-4-nitrophenyl)azo)phenyl)ethylamino) ethyl)trimethylammonium methyl sulphate; 2-(((1,3-Dihydro-1,3-dimethyl-2H-benzimidazol-2-ylidene)methyl)azo)-3-methylbenzothiazolium methyl sulphate; (2-((4-((2-Chloro-4-nitrophenyl)azo)phenyl)ethylamino)ethyl)trimethylammonium; 4-((2-Chlorophenyl)(4-(ethylimino)-3-methylcyclohexa-2,5-dien-1-ylidene)methyl)-N-ethyl-o-toluidine monohydrochloride; 2-(2-(4-((2-Chloroethyl)ethylamino)-o-tolyl)vinyl)-1,3,3-trimethyl-3H-indolium chloride.
Non-limiting examples of acid dyes are: derivatives of triphenylmethane, derivatives of xanthene, nitrated aromatic compounds, acid dyes containing one or more azo groups, pyrazolone azo dyes, derivatives of anthraquinone dyes, derivatives of phthalocyanine dyes. Non-limiting examples of direct dyes are: sulphonated azo compounds and metal complex direct dyes.
In the composition of the present invention, the ratio of the dye content to the pigment content in the treating composition ranges from about 0.001:1 to about 1000:1, and preferably ranges from about 0.01:1 to about 10:1, and more preferably range from 0.05:1 to about 1:1.
A wide range of useful colors can be imparted to wood using the process of the present invention. The color of wood treated with the preservative solutions described herein can be a variety of colors, such as grey, blue, green, brown, yellow, orange, black, red or other shades, depending upon the particular combination of the pigments, and their concentration. Dramatic improvement on the weathering properties can be achieved by incorporating the pigments into preservative systems as shown in
Laboratory accelerated weathering test (QUV Test: samples exposed to UV light and water spraying) also confirms that the wood samples treated with preservative plus pigment formulation demonstrated great UV photo-resistance.
The treating composition may be applied to wood by dipping, soaking, spraying, brushing, or any other means well known in the art. In a preferred embodiment, vacuum and/or pressure techniques are used to impregnate the wood in accord with this invention including the standard processes, such as the “Empty Cell” process, the “Modified Full Cell” process and the “Full Cell” process, and any other vacuum and/or pressure processes which are well known to those skilled in the art.
The standard processes are defined as described in AWPA Standard C1-03 “All Timber Products—Preservative Treatment by Pressure Processes”. In the “Empty Cell” process, prior to the introduction of preservative, materials are subjected to atmospheric air pressure (Lowry) or to higher air pressures (Rueping) of the necessary intensity and duration. In the “Modified Full Cell”, prior to introduction of preservative, materials are subjected to a vacuum of less than 77 kPa (22 inch Hg) (sea level equivalent). A final vacuum of not less than 77 kPa (22 inch Hg) (sea level equivalent) should be used. In the “Full Cell Process”, prior to introduction of preservative or during any period of condition prior to treatment, materials are subjected to a vacuum of not less than 77 kPa (22 inch Hg). A final vacuum of not less than 77 kPa (22 inch Hg) is used.
The present invention also provides a method for applying pigments to wood. In one embodiment, the method comprises the steps of treating wood with a treating fluid comprising a dispersion of micronized pigment particles according to conventional wood treatment cycles employing for example, the Full Cell or Empty Cell process, some combination thereof, or by dip or spray treatment.
It is preferable to color and preserve the wood simultaneously, however it can be desirable to treat and color the wood in two stages. Without departing from the teachings of this invention the wood may first be treated with a composition containing wood preservatives, and then contacted with a composition containing the pigment dispersion. It is also possible to apply the coloring agent to the wood initially, followed by the application of the preservative composition. The application of each component can be carried out as with the application of a two component solution.
The two step application is particularly useful in wood treatment processes in which the runoff from treatment with one component is to be collected and reused.
A variety of cellulosic products such as wood, paper, textiles, cotton and the like can be colored and preserved in accordance with this invention including hard and/or soft woods. In general, wood may thus be simultaneously colored and preserved.
Wood colored and preserved according to the method of this invention resists weathering and has many uses in the construction industry. Patio and pool decks, wood siding and beams, fence posts, garden ties and poles for outdoor or indoor use are just a few of the possible products which may incorporate wood treated according to the method described herein.
The following examples will serve to further illustrate the invention. Examples 1 through 10 demonstrate the preparation of pigment dispersion. Examples 15 through 22 demonstrate the preparation of the wood preservative treating compositions with and without the presence of pigment dispersions.
1500 grams of red iron oxide, 500 g yellow iron oxide and 56 g carbon black were added to a container containing 1594.0 g of water and 350.0 g of a commercially available solution of polycarboxylate ether dispersant. The mixture was mechanically stirred for about 20 minutes and then added to a grinding mill. The sample was ground for about 2.0 hours and a stable dispersion was obtained. The particle size of the dispersed product was analyzed by Horiba LA-910 Particle Size Distribution Analyzer (PSDA). The average particle size was 0.21 microns with a distribution range of 0.04 um to 1.0 um.
800 grams of red iron oxide, 200 g yellow iron oxide and 25 g carbon black were added to a container containing 795.0 g of water and 180 g of a modified poly carboxylic acid polymers dispersant. The mixture was mechanically stirred for about 20 minutes and then added to a grinding mill. The sample was ground for about 1.1 hours and a stable dispersion was obtained. The particle size of the dispersed product was analyzed by Horiba LA-910 Particle Size Distribution Analyzer (PSDA). The average particle size was 0.18 microns with a distribution range of 0.04 um to 1.5 um.
750 grams of red iron oxide, 250 g yellow iron oxide and 50 g black iron oxide were added to a container containing 1270 g of water and 180 g of a modified polycarboxylate ether type of dispersant. The mixture was mechanically stirred for about 20 minutes and then added to a grinding mill. The sample was ground for about 1 hour and a stable dispersion is obtained. The particle size of the dispersed product was analyzed by Horiba LA-910 Particle Size Distribution Analyzer (PSDA). The average particle size was 0.25 microns with a distribution range of 0.005 um to 1.5 um.
2000 g yellow iron oxide and 44 g carbon black were added to a container containing 2616.0 g of water and 340.0 g of a commercially available solution of polycarboxylate ether dispersant. The mixture was mechanically stirred for about 20 minutes and then added to a grinding mill. The sample was ground for about 2.5 hours and a stable dispersion obtained. The particle size of the dispersed product was analyzed by Horiba LA-910 Particle Size Distribution Analyzer (PSDA). The average particle size was preferably 0.19 microns with a distribution range of 0.01 um to 1.1 um.
2000 g yellow iron oxide and 198 g red iron oxide were added to a container containing 2923.0 g of water and 374.0 g of a commercially available solution of polycarboxylate ether dispersant. The mixture was mechanically stirred for about 20 minutes and then added to a grinding mill. The sample was ground for about 2.0 hours and a stable dispersion obtained. The particle size of the dispersed product was analyzed by Horiba LA-910 Particle Size Distribution Analyzer (PSDA). The average particle size was preferably 0.18 microns with a distribution range of 0.01 um to 1.2 um.
1000 g yellow iron oxide and 124 g red iron oxide were added to a container containing 1484.0 g of water and 202.0 g of a commercially available polycarboxylate ether type of dispersant. The mixture was mechanically stirred for about 20 minutes and then added to a grinding mill. The sample was ground for about 1.2 hours and a stable dispersion obtained. The particle size of the dispersed product was analyzed by Horiba LA-910 Particle Size Distribution Analyzer (PSDA). The average particle size was preferably 0.18 microns with a distribution range of 0.04 um to 1.0 um.
Eight hundred and ninety grams of yellow iron oxide, 110 g red iron oxide were added to a container containing 3000 g of water and 200 g of a commercially available modified polycarboxylate ether type of dispersant. The mixture was mechanically stirred for about 20 minutes and then added to a grinding mill. The sample was ground for about 1 hour and a stable dispersion obtained. The particle size of the dispersed product was analyzed by Horiba LA-910 Particle Size Distribution Analyzer (PSDA). The average particle size was preferably 0.24 microns with a distribution range of 0.010 um to 2.0 um.
Five hundred grams of organic pigment yellow PY65, 600 g of organic pigments red PR23 and 15 g organic pigment blue PB 15 were added to a container containing 3000 g of water and 450 g of a modified polyether with pigment affinic groups dispersant. The mixture is mechanically stirred for about 20 minutes and then added to a grinding mill. The sample was ground for about 1 hour and a stable dispersion obtained. The particle size of the dispersed product was analyzed by Horiba LA-910 Particle Size Distribution Analyzer (PSDA). The average particle size was 0.18 microns with a distribution range of 0.0050 um to 2.0 um.
Eight hundred grams of organic pigment yellow PY 13 and 100 g of organic pigments red PR254 were added to a container containing 4000 g of water and 500 g of a modified polymer with pigment affinity group dispersant. The mixture was mechanically stirred for about 20 minutes and then added to a grinding mill. The sample was ground for about 1 hour and a stable dispersion was obtained. The particle size of the dispersed product was analyzed by Horiba LA-910 Particle Size Distribution Analyzer (PSDA). The average particle size was 0.21 microns with a distribution range of 0.001 um to 2.0 um.
Five hundred grams of titanium dioxide is mixed with 450 grams of water and 50 grams of a modified polyacrylate polymer dispersants. The mixture is mechanically stirred for 5 minutes. The mixture is then placed in a grinding mill and ground for about 30 minutes. A stable dispersion is obtained with an average particle size of 0.29 microns.
Southern Yellow Pine, (measuring 2″×6″×4′) was simultaneously colored and preserved by the Full Cell treatment using a 1.1% MicroPro200 solution containing 0.73% micronized copper carbonate as copper oxide and 0.37% quaternary ammonium compound (dimethyl didecyl ammonium carbonate/bicarbonate), and 0.45% pigment solids from Example 1. The wood was initially placed under a vacuum of 27″ Hg for 30 minutes followed by the addition of the treating solution. The system was then pressurized for 30 minutes at a pressure of 110 lbs. per square inch. The resulting wood, when dried, was colored reddish brown and protected against wood destroying organisms.
Southern Yellow Pine, (measuring 2″×6″×4′) was simultaneously colored and preserved by a modified full cell treatment using a 1.2% MicroPro200 solution containing 0.80% micronized copper carbonate expressed as copper oxide and 0.40% quaternary ammonium compound (dimethyl didecyl ammonium carbonate/bicarbonate), and 0.50% pigment solids from Example 1. The wood was initially placed under a vacuum of 22″ Hg for 7 minutes followed by the addition of the treating solution. The system was then pressurized for 10 minutes at a pressure of 110 lbs. per square inch, followed with a 20 minutes final vacuum. The resulting wood, when dried, was colored reddish brown and protected against wood destroying organisms.
Southern Yellow Pine, (measuring 2″×6″×4′) was simultaneously colored and preserved by a modified full cell treating process using a 1.0% MicroPro200 solution containing 0.667% micronized copper carbonate expressed as copper oxide and 0.333% quaternary ammonium compound (dimethyl didecyl ammonium carbonate/bicarbonate), and 0.45% pigment solids from Example 5. The wood was initially placed under a vacuum of 22″ Hg for 5 minutes followed by the addition of the treating solution. The system was then pressurized for 5 minutes at a pressure of 110 lbs. per square inch, followed by a 25 minutes final vacuum. The resulting wood, when dried, was colored cedar-brown and protected against wood destroying organisms.
Southern Yellow Pine, (measuring 2″×6″×4′) was simultaneously colored and preserved by a modified full cell treating process using a 1.0% MicroPro200 solution containing 0.667% micronized copper carbonate expressed as copper oxide and 0.333% quaternary ammonium compound (dimethyl didecyl ammonium carbonate/bicarbonate), and 0.48% pigment solids from Example 5 and 0.024% of 2-(((4-Methoxyphenyl)methylhydrazono)methyl)-1,3,3-trimethyl-3H-indolium methyl sulphate dye. The wood was initially placed under a vacuum of 22″ Hg for 5 minutes followed by the addition of the treating solution. The system was then pressurized for 5 minutes at a pressure of 110 lbs. per square inch, followed by a 25 minutes final vacuum. The resulting wood, when dried, was colored brown and protected against wood destroying organisms.
Southern Yellow Pine blocks (1½″×2″×6″) were simultaneously colored and preserved utilizing the Lowry Empty Cell process using a 0.5% quaternary ammonium compounds based preservative (dimethyl didecyl ammonium chloride) plus 0.49% pigment solids from Example 2 and 0.030% hydroxyethyl cellulose binder. The resulting wood was air dried to a 20% moisture content and was colored a reddish brown color uniformly distributed on the surface of the treated wood. The wood was exposed under an accelerated tester (QUV) and found to exhibit great resistance to UV photo-degradation. Laboratory accelerated agar test indicated that the treated wood resist both attacks from brown rots and white rots.
50 grams of pigment concentrate from Example 5 were mixed with 3950 g dimethyldidecylammonium carbonate (DDA Quat) water solution containing 0.60% DDA Quat and 0.05% polyvinyl alcohol resin. The solution was used to treat red pine and ponderosa pine samples using the Full Cell process. The resulting wood was oven dried at 120° F. and was colored a cedar-brown color. Outdoor exposure studies indicated that the treated samples were resistant to biological deterioration and UV degradation.
Southern Yellow Pine blocks (½″×2″×6″) were simultaneously colored and preserved using the Full Cell treatment with a treating composition containing 0.10% copper 8-hydroxyquinolate plus 0.50% pigment dispersion from Example 1 with 0.005% a PVA type of binder. The Southern Yellow Pine blocks were placed in a cylinder and a vacuum of 30″ Hg applied for 15 minutes, the treating composition was then added to the cylinder and the system pressurized to 100 lbs. per square inch for 30 minutes. The resulting wood, when dried, was colored a reddish brown and was protected against wood destroying organisms.
Douglas fir and Hem fir wood samples were colored a brown color with a two-step process. Step I involved the treatment of wood with 0.8% dimethyldidecylammonium carbonate solution using the Full Cell process, followed by Step II treatment with a 1.0% pigment solution from Example 5. The treated wood showed bio-efficacy and color stability when exposed outside.
Southern pine, red pine and ponderosa pine samples were colored a darker reddish brown color with a two-step process. Step I involved the treatment of wood with a 2.0% pigment solution from Example 2 plus 0.015% a commercially available binder using a modified Full Cell process, followed by Step II treatment with a composition containing 0.05% tebuconazole and 0.005% bifenthrin. The treated samples demonstrated uniform surface coloration. The samples also demonstrated bio-efficacy in a field test evaluation.
Douglas fir and Hem fir samples were colored a darker reddish brown color with a two-step process. Step I involved the treatment of wood with a composition containing 1.0% dimethyldidecylammonium carbonate solution using the Full Cell process, followed by Step II treatment with a 1.0% pigment solution from Example 2 plus 0.01% a commercially available binder. The treated samples demonstrated uniform coloration on the surface and bio-efficacy in a field test evaluation.
Southern Yellow Pine, (measuring 2″×6″×4′) was simultaneously colored and preserved by a modified full cell treating process using a preservative solution containing 0.15% tebuconazole and 0.03% bifenthrin and 0.50% pigment solids from Example 1. The wood was initially placed under a vacuum of 22″ Hg for 5 minutes followed by the addition of the treating solution. The system was then pressurized for 5 minutes at a pressure of 110 lbs. per square inch, followed by a 25 minutes final vacuum. The resulting wood, when dried, was colored reddish brown color and protected against wood destroying organisms.
Southern Yellow Pine, (measuring 2″×6″×4′) was simultaneously colored and preserved by a modified full cell treating process using a preservative solution containing 0.10% tebuconazole and 0.02% bifenthrin and 0.50% pigment solids from Example 5 The wood was initially placed under a vacuum of 22″ Hg for 6 minutes followed by the addition of the treating solution. The system was then pressurized for 7 minutes at a pressure of 110 lbs. per square inch, followed by a 25 minutes final vacuum. The resulting wood, when dried, was colored cedar-brown and protected against wood destroying organisms.
The foregoing examples are intended to be merely illustrative and should not be construed or interpreted as being restrictive or otherwise limiting of the present invention.
This application is a continuation-in-part of U.S. Non-provisional application No. 11/299,522 filed on Dec. 12, 2005, which is a continuation-in-part of U.S. Non-provisional application No. 11/126,839 filed on May 11, 2005, which claims priority to U.S. Provisional application No. 60/570,659 filed on May 12, 2004, the disclosure of which is incorporated herein by reference; and is also a continuation-in-part of U.S. Non-provisional application No. 11/116,152 filed on Apr. 27, 2005, which claims priority to U.S. Provisional application No. 60/565,585 filed on Apr. 27, 2004, the disclosure of which is hereby incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| 60570659 | May 2004 | US | |
| 60565585 | Apr 2004 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 11299522 | Dec 2005 | US |
| Child | 11608508 | Dec 2006 | US |
| Parent | 11126839 | May 2005 | US |
| Child | 11299522 | Dec 2005 | US |
| Parent | 11116152 | Apr 2005 | US |
| Child | 11299522 | Dec 2005 | US |
