US 3839073 A
Method for producing wood having long lasting aesthetic value and resistance to wood destroying organisms comprises coloring the wood with a water dispersible coloring agent and preserving the wood with a water-soluble preserving agent simultaneously or sequentially in either order.
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Description (OCR text may contain errors)
United States Patent [191 Hill [ Oct.1,1974
l AESTHETIC woon PRODUCT  Inventor: Rotter- ETliiillfclavton,Moi
 Assignee: RappersW135i:ITTETI HTSBUQET 122] Filedz Mg [211 PPl.N0.:280,075
Related [1.8. Application Data  Continuation-in-part of Ser. No. 30,348, April 20,
 US. Cl 117/57, 117/69, 117/147, 21/7, 8/65  Int. Cl B44d l/l6  Field of Search 117/57, 69, 147; 21/7; 8/65  References Cited UNITED STATES PATENTS 5/1940 Hager ..l17/15l 7/1959 Baker ..2l/7
Primary Examiner-Michael Sofocleous Assistant ExaminerWilliarn R. Trenor Attorney, Agent, or Firm-Olin E. Williams; Oscar B. Brumback; Herbert J Zeh, Jr.
[ 5 7 ABSTRACT Method for producing wood having long lasting aesthetic value and resistance to wood destroying. organisms comprises coloring the wood with awater dispersible coloring agent and preserving the wood with a water-soluble preserving agent simultaneously or sequentially in either order.
13 Claims, N0 Drawings AESTHETIC WOOD PRODUCT CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation-in-part of application Ser. No. 30,348 filed on Apr. 20, 1970, now abandoned.
BACKGROUND OF THE INVENTION I. Field of the Invention This invention relates to a method for both coloring and preserving wood and, more particularly, to a method of improving the aesthetic value of wood and its resistance to the various destructive agencies of wood such as, for example, water, rot, fungus, and various other wood destroying organisms.
There is and has been a long felt need to produce wood products that are artistically and aesthetically acceptable to the public and yet are preserved from the destructive agencies of wood. For example, distribution or transmission poles, the socalled telephone poles having been preserved with creosote or the like are generally dark brown or black in color and in many cases the public objects to their use. The black or dark brown poles cannot, subsequently, be coated with a coloring agent as the oily surface of the pole prevents the adherence of the coloring agents to the pole.
In other cases where wood products are used such as, for example, in the home building industry and the fencing and siding industry, wood products that are protected against the destructive agencies of wood are more acceptable to the public if a variety of color choices are available. Unfortunately, several wood preserving solutions used in protecting the wood against the various wood destructive agencies impart their own definite color to the wood and, accordingly, this restricts the available color spectrum to the type of wood preservative used.
There are several known methods by which wood can be colored and by which wood can be preserved against various wood destructive agencies. But there are few known methods by which wood can both be colored and preserved with any success.
For example, a well known and successful wood preservative composition is pentachlorophcnol. In the typical wood preserving process using pentachlorophcnol it is dissolved in a solvent such as a petroleum-type solvent and, then, impregnated into the wood by any well known pressure or thermal process. The petroleumtype solvent is removed from the wood leaving an oily film on the surface of the wood. If the wood is to be painted several months of air seasoning after treatment are required to permit a sufficient evaporation of the oily solvent. During this period of seasoning, a portion of the preservative may move to the surface of the wood with the solvent and, thus, a retention of the preservative In the wood is reduced below that contemplated by the treatment. I
If the wood is immediately painted, the oil base paints or pigmented latex coatings will not adhere to the treated wood. In any case, there are few known oil base paints or latex coatings that will adhere to the wood and even those that do adhere to the wood form blisters, flake or chalk off the wood in a relatively short period of time. Accordingly, this short period of color retention is not coextensive with the useful life of the wood in most of its applications and therefore objectionable.
Alternatively, it has been proposed to first color the wood with coloring agents such as an oil base or latex paint and then to treat the wood with a wood preservative. Most all of the known oil base or latex paints form a surface film over the wood and accordingly prevent the penetration of the subsequent wood preservatives into the interior of the wood because the coatings render the poles nonbreathable. Additionally, some of the wood preservative solutions are incompatable with the components of the oil base or latex coatings and within a very short period of time destroy the coatings.
2. Description of the Prior Art One known method of simultaneously coloring and preserving wood is described in British Pat. No. 1,170,003. An aqueous composition including a waterborne preservative salt, a water dispersible pigment and a synthetic polymer are impregnated into the wood by conventional techniques. The water-borne preservative salt protects the wood against the various wood destructive agencies; the water dispersible pigments imparts color to the wood; and, the synthetic polymer binds the pigments to the wood fibers. The British patent is typical of the prior art as it states that synthetic polymers are essential to bind the pigments to the wood fiber. Thus, those skilled in the art have always considered the use of synthetic polymers as an essential ingredient to impart color to the wood with water dispersible pigments in a color/preserving system.
Quite surprisingly, I have discovered that a synthetic polymer is not essential to color wood with a water dispersible pigment and that the so-called essential polymer may be eliminated from the wood coloring and preserving composition.
SUMMARY OF THE INVENTION In accordance with my invention, a method for coloring and preserving wood comprises (1) coloring the wood with a composition consisting essentially of an aqueous dispersible pigment and water, and (2) preserving the wood with a composition consisting essentially of an aqueous solution of an inorganic or organic water soluble preservative that does not adversely affect the water dispersible pigment applied to the wood whereby the coloring and preserving of the wood may occur simultaneously or sequentially in either order.
DETAILED DESCRIPTION OF THE INVENTION The process of my invention is characterized by two basic steps which may be carried out simultaneously or sequentially in either order. One step of my process relates to the coloring of wood with a coloring agent and the other step relates to the preserving of wood with a wood preservative.
The coloring agents that are useful in the method of my invention are water dispersible pigments well known to those skilled in the art and include such pigments, for example, as titanium dioxide white, yellow oxide, chrome yellow, Hansa yellow, azo yellow, molybdate orange, dinitroniline orange, toluidine red medium, red oxide light, burnt sienna, phthalobyanine blue, phthalocyanine green, lamp black and the like.
The water dispersible pigments are preferably carried in aqueous pigment compositions which are prepared by adding the water dispersible pigments to water containing a conventional dispersing agent and thoroughly stirring the ingredients together.
ln accordance with the invention, the pigment concentration in the aqueous pigment composition may vary from about 0.001% to about 40.0%; the concentration of the pigment in the composition will depend on the desired intensity of the color to be imparted to the treated wood.
The aqueous pigment compositions useful in the method of this invention may also contain surfactants or wetting agents to aid in dispersing the pigment into the outer fibers of the treated wood. The aqueous pigment compositions may be modified with secondary materials such as, for example, extenders and adhesives and other materials having favorable action on the performance on the aqueous pigment composition and which do not interfere to any substantial extent with the breathability of the colored wood and its treatment with preserving agents. Extenders that may be used include, for example, barium sulfate, zinc oxide, basic lead carbonate, calcium carbonate, silica and various other non-alkali metal silicates.
The preserving agents that are useful in the method of my invention are water-soluble preserving agents well known to those skilled in the art which preserving agents do not adversely affect the color imparted to the wood by the aqueous dispersible pigments.
Suitable water-soluble preserving agents include salts of halogenated hydroxy containing compounds, acid copper chromate (31.87% CuO, 68.2% CrO ammoniacal copper arsenite (9.8% CuO, 50.2% AS205), chromated copper arsenate, type A (65.5% CrO 18.1% CuO, 16.4% A5 chromated copper arsenate, type B (35.3% CuO, 19.6% CuO, 45.1% As O chromated copper arsenate, type C (47.5% CrO 18.5% CuO, 34.0% As O,-,), chromated zinc chloride G0,, 80% ZnO), copperized chromated zinc arsenate (13.0% CuO, 20.3% CrO 11.5% ZnO, 55.2% A5 0 fluor chrome arsenate phenol (22% fluoride, 37% CrO As O,-,, 16% dinitrophenol), copper sulfate, zinc chloride, mercury chloride, sodium, potassium and ammonium borates, sodium fluoride, carbamates, phosphates and acetates and quaternary ammonium compounds such as alkyl (C,C dimethylbenzylammonium chloride.
The water-soluble salts of halogenated hydroxy containing compounds suitable for the practice of this invention include the alkali metal, NH,, copper and amine salts of halogenated monohydric and polyhydric phenols and halogenated benzophenones and they embrace salts of halogenated parasiticidal phenols including alkyl and phenyl substituted phenols which have been chlorinated or brominated. Halogenated hydroxy compounds, the salts of which are of particular value in the practice of this invention, are those defined by a formula selected from the group consisting of wherein R is selected from the group consisting of hydrogen, methyl, phenyl, chlorine and bromine, X is bromine or chlorine and n is an integer from 1 to 4 inelusive,
OH OH 1 o Q' Q x' X wherein X is chlorine or bromine and is attached at the 4,4 or 5,5 positions of the phenyl rings.
Suitable water-soluble salts of halogenated hydroxy containing compounds may include salts of monohydric halophenols having mixed chlorine and bromine as well as monohydric halophenols having a single halogen species such as, for example, 2-bromo-4- chlorophenol, 2-bromo-4,6-dichlorophenol, 2,3,6- tribromo-p-cresol, 2,4,6-trichloro-m-cresol, 2,4,6- tribromo-m-cresol, 2,6-dibromo-4-chlorophenol, 2- chloro-4-phenylphenol, 2,3,4-trichlorophenol, 2,3,6- trichlorophenol, 2-bromo-4-phenylphenol, 4-bromo-2- phenylphenol, 4-chloro-2-phenylphenol, 4,6-dibromoo-cresol, 2,5-dibromo-p-cresol, 3,6-dibromo-2-chlorop-cresol, 2,4,5-trichloro-phenol, 4-bromophenol, 2- bromophenol, 2,4-dibromophenol, 4-chloro-m-cresol, 2-chloro-4,6-dibromophenol, pentachlorophenol, pentabromophenol, 2,3,5,6-tetrach|orophenol, 2,3,4,5- tetrachlorophenol, 2,3,4,6-tetrachlorophenol, 2,3,5,6-tetrachloro-p-cresol, 2,4,5,6-tetrabromomOcresol, 2,4,6-trichlorophenol, 3,4-dichlorophenol, 2,3-dichlorophenol, 2,5-dichlorophe'nol, 2,6- dichlorophenol, 2,4-dichlorophenol, 4-chlorophenol, 3-chlorophenol and 2-chlorophenol.
Suitable salts of halogenated hydroxy containing compounds may include salts of polyhydric phenols and benzophenones such as, for example, 4,4- dichloro-2, 2'-diphenol, 4,4'-dibromo-2, 2-diphenol, 4,4-dibromo-2,2'-dihydroxybenzophenone, 5 ,5 dichloro-2,2'-diphenol, 5,5-dibromo-2,2-diphenol, 4,4-dibromo-2,2-diphenylmethane and 2,2- dyhydroxy-5,5'-dichlorodiphenylmethane. Particularly suitable salts include potassium, lithium, sodium, copper ethanolamine, methylamine, ethylamine, trimethylamine, propylamine, triethanolamine and the like.
Conventional and well known techniques of treating wood may be employed in carrying out the method of my invention. As previously stated, there are two basic steps to the method of my invention which include (1) a color imparting step and (2) a preserving step. In the color imparting and the preserving steps of my invention the coloring and preserving agents may be applied to the wood by brushing, spraying, dipping, soaking and the like or by impregnating in accordance with well known thermal or pressure techniques. The pressure techniques include both the empty cell and the full cell" procedures well known to those skilled in the art.
Generally speaking, the pressure techniques are preferred for injecting the wood preservatives into the wood. in the full cell" process, it is desirable to retain us much of the preservative forced into the wood during the pressure period as possible to leave a maximum concentration of the preservative in the wood. in the empty cell" process, on the other hand, part of the preservative forced into the wood under pressure is subsequently recovered so that the cells of the wood tend to be coated with the preservative rather than filled with the preservative. Neither process actually leaves the cells of the wood full or empty, but the names full cell and empty cell are sufficiently accurate for practical purposes.
The full cell process is especially advantageous when it is desired to inject as much preservative solution into the wood as the wood can possibly take. The empty cell method is required when it is desirable to V secure as deep penetration as possible with a limited final retention of the liquid. When wood is to be treated with water solutions of preservative salts, it is customary to use the full cell process and to force into the wood all the liquid that the wood can hold.
lt is preferred in carrying out the method of my invention to first color the wood in accordance with the invention and then subsequently to preserve the wood with a preservative; however, the wood may be preserved first and subsequently colored, or simultaneously preserved and colored as desired.
A variety of woods can be colored and preserved in accordance with the invention and they include green hardwood and green or seasoned softwoods. Illustrative varieties of hardwood include maple, beech, ash, mahogny, walnut, hickory, gum and oak. Illustrative varieties of softwoods include southern pine, ponderosa pine, Douglas Fir, Hemlock, Western Larch, Jack Pine, Lodge Pole pine, red pine, Northern white pine, sugar pine, Western white pine, red cedar, and white cedar.
The method of my invention is particularly useful for treating wood products that are used as energy and transmission poles, crossarms, fence posts, siding, flooring, platforms and the like. The following examples will illustrate the invention, parts and per cents are by weight unless otherwise indicated:
EXAMPLE 1 Southern yellow pine wafers are simultaneously colored and preserved by dipping in an aqueous color/- preserving composition comprising 90 parts water, parts of iron oxide pigment and 10 parts preservative solution (34% AS305, 26.6% Cr O 14.8% CuO and 24.6% H O). The wafers exhibit a red color and are protected against wood destroying organisms.
EXAMPLE 2 Southern yellow pine wafers are colored by dipping in an aqueous pigment composition containing 0.5% iron oxide, drained and preserved by pressure treatment with an aqueous preservative solution (34% As- O,-,, 26.6% Cr- O;,, 14.8% CuO and 24.6% H O). The
wafers exhibit a red color and are protected against wood destroying organisms.
EXAMPLE 3 Southern yellow pine wafers are preserved by pressure treatment with an aqueous preservative solution (34% AS205, 26.6% cl'gog, 14.8% CuO, and 24.6% H 0) and colored by dipping in an aqueous pigment composition containing 0.5% iron oxide. The wafers exhibit a red color and are protected against wood destroying organisms.
What is claimed is:
1. A method of producing wood that has long lasting aesthetic value and that is resistant to wood destroying organisms comprising:
a. first, coloring the wood with a coloring agent consisting essentially of an aqueous dispersion of a water dispersible pigment; and second, preserving the wood with a wood preserving composition consisting essentially of an aqueous solution of water soluble wood preservative wherein the wood preservative does not adversely affect the water dispersible pigment applied to the wood.
2. Method as in claim 1 wherein the water soluble wood preservative is an organic salt.
3. Method as in claim 1 wherein the water soluble wood preservative is a salt of a halogenated phenol.
4. Method as in claim 1 wherein the wood is in the form of a pole.
5. Method as in claim 1 wherein the coloring agent imparts a gray color to the wood.
6. A Method of producing wood that has long lasting aesthetic value and that is resistant to wood destroying organisms comprising:
a. first, preserving the wood with a wood preserving composition consisting essentially of an aqueous solution of a water soluble wood preservative, and;
b. second, coloring the wood with a coloring agent consisting essentially of an aqueous dispersion of a water dispersible pigment wherein the wood preservative does not adversely affect the water dispersible pigment applied to the wood.
7. Method as in claim 6 wherein the water soluble wood preservative is a salt of a halogenated phenol.
8. Method as in claim 6 wherein the wood is in the form of a pole.
9. Method as in claim 6 wherein the coloring agent imparts a gray color to the wood.
10. Method as in claim 6 wherein the coloring of the wood and the preserving of the wood are done simultaneously with a composition consisting of an aqueous dispersion of the water dispersible pigment in an aqueous solution of the water soluble wood preservative.
11. Method as in claim 10 wherein the water soluble wood preservative is a salt of a halogenated phenol.
12. Method as in claim 10 wherein the wood is in the form of a pole.
13. Method as in claim 10 wherein the coloring agent imparts a gray color to the wood.