US961123A - Art of coloring and fireproofing wood. - Google Patents

Description

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5 UNITED STATES WILLIAM AUGUSTUS HALL, OF NEW YORK,

N. Y., ASSIGNOR T0 AMERICAN MAHOGANY COMPANY, A CORPORATION OF MAINE.

ART OF COLORING AND FIREPROOFING WOOD.

. Specification of Letters Patent.

Applicationfiled June 6, 1908. 1 Serial No. 437,078.

Patented June 14, 1910.

To all whom it may concern:

Be it known that I, WILLIAM A. HALL, a citizen of .the United States, residing at New York, in the county of New York and State of New York, have invented or discovered certain new and useful Improvements in the Art of Coloring and Fireproofing Wood, of which the following is a specification.

This invention relates to the art of transforming wood by coloring and fireproofing the same, so as to produce, from the cheaper or more common varietiesof wood, such as birch, maple or gumwood, close fireproofed imitations of rarer or more expensive woods, such as black walnut, mahogany, etc.

The object of the invention is accomplished by a novel method of treating the lnexpensive woods so as to render them fire proof and give them the appearance and texture throughout their bodies of the more costly woods.

' The invention is carried into effect by causing suitable coloring and fireproofing solutions to permeate the wood and to be diffused throughout its body so that when the wood is cut up, in making cabinet work, or for other purposes, all parts of it will be suitably colored and will be of a fireproof character, and there will be practically no uncolored, non-fireproofed streaks in the wood, but the coloring and fireproofing materials will be infused and diffused throughout the wood, but with considerably more of the coloring matter deposited in the softer or more porous portions of the wood, such as the annual rings and open grain vessels, thereby resulting in a very prominent development of the grain or figure of the wood.

The invention may be carried into effect either by what is known as the vacuum and pressure process, or by What may be referred to as the open vat treatment.

In practicing the invention by the vacuum and pressure process well-dried lumber, in the shape of boards, planks, fiitches or deals, of any convenient size, is subjected, in a closed receptacle, to a vacuum action sufiiciently powerful and continued sufficiently long to remove from the wood practically all the air therein contained, so as to make it absorbent or receptive to the fluids to be applied later. It has been found preferable, during the vacuum process, to subject the wood to a moderate heat of say from 90 to "100 R, which has a tendency to open the pores of the wood. A combined coloring and fireproofing solution is then drawn or pumped into the receptacle or chamber containing the wood until the wood is fully immersed in such solution. The coloring and fireproofing solution may be applied either hot or cold (preferably the former) accord ing to its characteristics, and the solution will be rapidly taken up by the absorbent Wood. When the receptacle is filled with the solution, hydraulic or pneumatic pressure, preferably of say 200 to 300 pounds or more to the square inch, is applied to the chamber of the receptacle and 1S maintained until the wood is impregnated by the coloring and fireproofing solution to as great a degree as possible; the time required for this varying from two to three hours to ten or twelve hours or more, according to the thickness or hardness of the lumber under treatiient and the amount of pressure maintaine The coloring solutions used may be of any character that have a sufiiciently high capillary activity, but alkaline aqueous solutions of bark or wood extract, such as those pro duced from hemlock, spruce or mahogany, are preferred, the coloring materials selected of course being those which will not be injured to any extent by temperatures of 212 F., or thereabout.

The fireproofing solutions which are to be mixed with the alkaline coloring solutions, must be of such a character as not to precipitate the coloring solutions, and the coloring solutions must be of such a characteras not to injure or deteriorate the fireproofing solutions in any way, by reason of being antagonistic thereto. The fireproofing composition which I have found, by extended experiments, to be most satisfactory consists of a mixture of sulfate of ammonia and phosphate of soda. Sulfate of ammonia is a very strong fireproofing substance which not only mineralizes the fiber of the Wood, but, which when subjected to heat, discharges ammonia gas which has a tendency to extinguish flame. Owing, however, to the acid character of this salt it is not suitable for use alone with alkaline coloring solutions, as it has a tendency to precipitate such solutions, so that they can not be made to permeate the wood as thoroughly as may be desired. Also this acid salt cannot be used 110 alone as a fireproofing substance in connection with alkaline coloring solutions, for the reason that the fireproofing qualities of the. substance are greatly impaired or destroye I have discovered that by mixing a suitable proportion of phosphate of soda, which is an alkaline fireproofing salt, with the sulfate of ammonia the acid of the latter is neutralized and the whole mixture is rendered neutral or slightly alkaline; and such fireproofing mixture will not precipitate or injure the alkaline coloring solutions or substances with which it may be mixed, nor will the fireproofing qualities of the mixture be impaired by the alkaline solution. Vhile phosphate of soda is not, of itself, so strong a fireproofing substance as sulfate of ammonia, I have found that a mixture of these two salts is more strongly fireproofing than either when used alone, for the reason that the sulfate of ammonia is not, of itself, a very good mineralizing salt, its fireproofing qualities being largely due to the evolution of gases which do not support combustion; whereas the phosphate of soda is a very strong mineralizer, but is deficient in a capability of evolving flame-extinguishing gases. While the invention is not to be understood as being limited to any particular proportions of these fireproofing salts in the mixture, it may be stated that experiments have determined that phosphate of soda may, and preferably will, form from onethird to one half of the mixture.

Instead of using sulfate of ammonia in the fireproofing mixture, phosphate of ammonia might be used with equally good effeet; but owing to the much greater cost of the latter salt the former will preferably be employed. Also, instead of using phosphate of soda as an alkaline substance in the fireproofing mixture sulfid of soda might be employed; but the former salt is much preferred owing to its greater elliciency. Other fireproofing substances or solutions which, either alone or when combined together will be of a neutral or alkaline character, or which will not be deteriorative of or injurious to the coloring solutions, may also be used in place of the preferred salts or substances above mentioned; and the invention or discovery is therefore not to be understood as being limited to any particular fireproofing substances so long as those employed form a composition which is of a neutral or alkaline character and which is harmonious with or non-antagonistic to the alkaline coloring solutions.

Instead of effecting the coloring and fireproofing of the wood by the vacuum and pressure process above described, well-dried wood may be immersed in a coloring and fireproofing solution, of the character hereinbefore indicated, contained in an open vat by such alkaline solutions. But

or receptacle, and in which it may be boiled for two or more days, tocause the coloring and fireproofing solutions to permeate the wood and to be properly diffused therein;

or, instead of being boiled in a combined coloring and fireproofingsolution the wood may first be boiled in the coloring solution in an open vat and afterward plunged into a cold fireproofing solution which, owing to contraction, will be caused to be absorbed by or struck into the wood; and this cold fireproofing solution may afterward be heated, and by boiling the wood therein for some time the coloring and fireproofing materials will be thoroughly dilfused throughout the wood.

It will be understood that wood which has been subjected to a coloring and tireproofing treatment by either of the methods above described will be so transformed as to closely resemble the higher priced wood which it may be desired to imitate, according to the character of the coloring solutions which may be employed in this treatment; and such wood will also be rendered fireproof. The treatment of the wood by either of the methods above described has atendency to harden and toughen the wood, and also serves greatly to develop the grain thereof, so that natural woods having but little grain figure will come out with a highly developed and beautifully figured grain, and will therefore be very desirable for any purpose where an ornamental fireproofed wood may be employed. This result is largely due to pigment-like deposits of the coloring matters in the grain cells, together with the fireproofing salts, such deposits resulting from precipitation of the coloring matters from the coloring solutions partly by dialyzation and partly by the effect of the weak natural acids contained in the wood.

Having thus described 111 invention I claim and desire to secure by etters Patent:

1. The herein described fireproofed and artificially colored wood, having harmonious coloring and fireproofing materials distributed and diffused together throughout the wood, and the grain of the wood highly developed.

2. The herein described fireproofed and artificially colored wood, having an artificial coloring material and a mixture of acid and alkaline fireproofing salts distributed and diffused throughout the same, and the grain of the wood highly developed.

3. The herein described fireproofed and artificially colored wood, having an artificial coloring material and a mixture of sulfate of ammonia and phosphate of soda distributed and diffused throughout the same, and the grain of the wood highly de-' veloped.

4. The herein described process for colorcoloring and fireproofing materialsously, the coloring solution hein of an alkaline'character, and the fireproo material consisting of a mixture of sulfate of ammonia and phosphate of soda.

In testimony whereof I aflix my signature, in presence of two witnesses.

WILLIAM AUGUSTUS HALL.

Witnesses:

JOHN CARRINGTOK YATES, WALTER M. SCHEUMAKER.