US2545459A - Method of making glue from wood and a lumber product - Google Patents

Description

Patented Mar. 20, 1951 METHOD OFv MAKING GLUE FROM WOOD AND A LUMBER PRODUCT Worth. (3. Q1355, Seattle, Wash, assignor, by mesne assignmen s, to Edward S Heller No Drawing, Application-November 30, 1946,

Serial No. 713,393

' 3 Claims. (01. 106-163) This invention relates to glues-and adhesives and it has reference more particularly to the production of a glue from wood and to the uses of the glue.

It is the principal object of the present invention to produce a glue of high quality from the cellulose free residue resulting from the action of cellulose consuming fungi on wood or other ligno-cellulosic material of vegetable origin and Whichglue is characterized by its property of setting while hot and wet. It is also an object of this invention to provide an economical and feasible method of treating wood for the quick production of a wood .sub- Stantially cellulose free residue and in a method of manufacturing the present glue from this residue. 1

Another object of my invention is to produce a plastic mixture, including the present glue as apart thereof and from Which lumber and other articles may be made by consolidating the mixture under an application of heat and pressure. Another object of the invention is to produce a glue that may be reacted with natural wood acids, selected acids or chemical bases to cause it to set while wet and hot. Still another object of my invention is to react the present glue with certain organic acids to produce a reaction product that may be used to great advantage in the making of sheet lumber from ligno-cellulose fibers by reason of itsproperty of setting while hot and wet.

Other objects, pertinent to the invention will be disclosed and described in the following specifications A The basis on which the present invention is predicated is my discovery that a glue of excellent quality can be made from that particular residue that is the result of the action of cellulose consuming fun i on the wood. Furthermore. the present invention takes into consideration as an important part thereof, my discovery that the glue, produced by wet grinding this wood residue to a thin paste-like consistency will react with the acids found in wood; or with certain selected acids or chemical bases to form a reaction prodnot that will set while wet and hot, and thatthis reaction may be effected in the making ,of sheet lumber from a, mixture of the glue and fiberized wood either by reason of thefwood acids that occur naturally in the wood fibers, or by the addition of the reacting agent to the wood or to the glue before they are combined in the mixture for consolidation by heat and pressure.

Insofar as the present invention concerns the 2 quick production of a residue from wood for the manufacture of my glue therefrom, it takes into consideration the. introduction into and the in cubation in the wood of those particular micro-'- organisms which constitute the cellulose con-. suming fungi and also it gives consideration to my discovery that such cellulose consuming fungi can only be produced to an extent satisfactory for the present purpose in wood that contains the natural wood acids in a certain percentage or to which certain acids are added.

.In carrying out the principal objects of the invention that pertain to the making of the glue itself, I select, preferably a wood which in its natural state contains that certain percent of Wood acids that is most effective for the incuba-. tion of cellulose consuming fungi therein. If, however, the wood that is available or selected for use does not contain any or the proper per centage of acid, then its acid content is adjusted substantially to the equivalent of from 1% to 5% of acetic acid, on the basis of the dry weight of the wood.

In the above use of the word adjusted, I.

mean in general that if 1% of acetic acid when added to the wood gives the desired acidity for the present purposathen approximately 6% of tannic acid could be used to give the same result; that is, to give the same degree of acidity, and this is by reason of the fact that the tannic acid molecule is about six times as heavy as the acetic acid molecue. Other acids that may be used to effect this adjustment are rosin acids, gallic acid, etc.

A wood that I have employed with most satisfactory results in the making of my glue, and which by reason of its containing in its natural state a percent of natural wood acids that is most satisfactory for the production of cellulose consuming fungi and therefore needs no adjustment in its acidity, is Douglas fir. A wood that is lacking in the required percentage of the wood acids and therefore must have its acidity adjusted is hemlock.

Preparatory to its treatment, the wood that is selected for use is reduced to the form of small pieces, chips or to sawdust, and after its acidity has been tested and adjusted, if such is required; a cellulose consuming fungi, preferably the specific fungus Polyporus schweiniteii is thoroughly mixed therewith. This mixing of the reduced wood and fungi should be done in such manner as to evenly disperse the micro-organisms through the mixture in great abundance. As a practical and economical means of effecting this mixing and distribution, I pass the wood in the form of sawdust, chips or pieces and a fungi bearing material together through a wood grinder of a character whereby both may be reduced to fine condition and thoroughly and evenly mixed.

The ground mixture of wood and fungi containing material is then maintained under those conditions of temperature, moisture and air that are most favorable for the multiplication and growth of the micro-organisms that constitute the cellulose consuming fungi. These conditions are well known to persons skilled in the profession of bacteriology. The mixture should comprise a considerable proportion of water at a temperature of from 60 F. to 90 F. in the presence of the wood acid and warmth that is best for the rapid incubation and growth of the fungi. Under these proper conditions, the fungi multiplies or grows rapidly and feeds upon the cellulose constituent of the wood, and the wood is thus reduced quickly to about one-third of its original weight. The incubation of the fungi in the mixture should be continued for a period of such length that the residue is substantially free of cellulose. This usually requires ten days or more to accomplish, depending upon the degree of subdivision of the wood and conditions under which it is maintained.

The residue that is left by the fungi action on the wood over the designated period, contains very little of the original cellulose. It is brown in color, soft and friable and by acid analysis comprises 50% or more of lignin. However, the lignin residue differs from the natural lignin of the wood in that about 70% of it is soluble in 1% sodium hydroxide solution; this not being the case of the natural lignin.

The basis of the present invention pertaining to the manufacture of a glue, resides in the use of the substantially cellulose free residue, and it is not material whether the removal of the cellulose was by natural process or artificially accomplished b the incubation of cellulose consuming fungi on the wood. Therefore, I do not intend that the invention shall be restricted or limited in its broad aspect to the action of any particular fungi but rather that it shall take into consideration that the production of the residue in any way or by use of any micro-organisms that will, by action on the wood, leave a residue that is substantially free of cellulose, and otherwise satisfactory for the making of the glue therefrom.

Fungi other than the one previously named, and which may be used satisfactorily and in the same way for the production of the desired wood residue, are Fomes Toseus, Fomes Zaricis and. Fomes pimcola. In general, aerobic microorganisms are preferred although anaerobic micro-organisms, such as thermo-phillic bacteria, that selectively consume cellulose, may be adapted. to the present use by persons skilled in bacteriology.

To make a glue from the residue produced by the fungi action on wood as above described, the residue is reduced to a paste-like mass. This reduction, preferably, is accomplished by grinding the residue in a ball mill in the presence of about four parts of water to each part of dry residue. Grinding should continue until a very fine creamy substance is formed. The consistency of this may be varied by use of more or less liquid. This substance, which constitutes the glue or adhesive of my invention, may, in this condition, be easily spread and easily mixed with other materials for use as a bonding agent.

To use the glue as a bonding agent in the making of sheet lumber from fiberized ligno-cellulosic fibers, 10% to 15% of the glue, by dry weight, is mixed with wood chips. Mixing is preferably effected by passing the materials at the same time through an attrition type grinder, thus to reduce the wood chips to fibers and coincident with their production, to individually coat them with the glue. The fibers, so coated, should be in a damp state, containing approximately 40% to moisture.

The glue coated fibers are then sifted through a screen of such mesh as to separate them each from the other to the maximum extent, and to allow the fibers to fall in hap-hazard manner cries-cross on to a plate or platen to form a matted layer of substantial thickness. The layer of fibers is then consolidated between the platens of a press under the action of heat of approximately 350 F. and pressure of from 50 to 500 pounds per sq. in. to form the layer into a solid board or sheet of lumber. Under the consolidating action of heat and pressure, a board one-half inch thick can be removed from the press in about five minutes while still containing up to 40% moisture, on the basis of the dry weight of the board, without the board exploding under the action of contained steam; this being due to the fact that the glue consolidates and sets in the presence of water and acids in the wood fibers to form a solid adhesive and the present board differs radically from a board made from damp wood fibers alone in that such a board cannot be re,- moved from a hot press until dry or until the press has been cooled below the steam producing temperature.

In the making of plywood, the glue as above produced maybe spread on the surfaces of the wood plies in the usual manner and by use of the usually used machines, and when the glued surfaces of the plywood sheets are pressed together in a hot platen press and held under pressure until the glue has set, it will be found that the glue has an adhesive value of 800 pounds or more to the square inch of sheer strength and to have an excellent water resistance in that the joint may be soaked for many weeks without showing any sign of joint parting.

It is to be pointed out that both in the making of sheet lumber from fiberized wood, containing acid, and in the making of plywood from an acid containing wood, the wood acids react with the glue to cause it to set or solidify and thus permit the board to b removed from the press before the glue is dry and while still hot. The reaction, however, is more pronounced in the case of the fibers than in plywood by reason of a more intimate contact between the fibers and.

glue.

The reaction bztween natural wood acids and the present glue results in a reaction product that will set while hot and Wet and can be removed from the press platens at high pressing temperatures and while still containing up to 40% moisture in the board.

The same type of chemical reaction with the glue may be obtained by use of many organic acids other than those of the wood, notably carbolic acid, tannic acid and acetic acid.

It is further to be explainedthat the reaction product may be prepared before being added as a bonding agent to the wood fibers. Or, if the wood fibers contain sufficient acetic acid, tannic acid or rosin acids, the reaction product is lower methoxyl percentage.

formed in the board during the pressing operation.

Another type of reaction product which causes the plastic to set in the board while hot and wet is of the general class obtained by reacting the glue with chemical bases. These may be either organic or inorganic alkaline substances. Three examples of inorganic reactions are the reactions of calcium hydroxide, magnesium hydroxide and aluminum hydroxide.

An example of a reaction with an organicbase is the reaction product obtained by treating the wood plastic or glue with aniline. In each case the reaction product thickens a wood plastic suspension in water.

The plastic or glue itself as produced from wood in an acid condition by the action of the fungus Polyporus schweim'tzii may contain 73% or more of lignin by acid analysis, but this lignin differs from natural lignin in that it shows a The product of the action of the fungus also shows a pentosan content as high as 9%. When the residue of the action of the fungi is ground to a fine paste like mass and is used as glue, both the lignin content and the pentosan content produce bonding action, particularly in the presence of moisture.

In the use of the term substantially cellulose free residue in the following claims, I mean a residue containing from 2% to 12% of cellulose based on the weight of the dry residue.

' Having thus described my invention, what I claim as new therein and desire to secure by Letters Patent is:

1. An article of manufacture comprising a compressed mixture, unified by heat and pressure to form a lumber product; said mixture comprising ligno-cellulosic fibers in predominating amount, and. a bonding agent of wet ground brown rotted wood containing from 1% to 5% of acetic acid.

2. An article of manufacture comprising a. compressed mixture, unified under heat and pres- Number Name Date 726,029 Classen Apr. 21, 1903 1,724,393 Carpenter Aug. 13, 1929 FOREIGN PATENTS Number Country Date 119,400 Australia Jan. 3, 1945 531,409 France Jan. 12, 1922 334,494 Germany Mar. 14, 1921 sure to form a lumber product; said mixture comprising raw Wood fibers in predominating amount, and a bonding agent of wet ground brown rotted wood containing from 1% to 5% 0f acetic acid.

3. The method of making a glue forming material from wood, comprising grinding together a mixture of wood and cellulose consuming fungi, adjusting the pH of the mixture to acid, causing incubation of the fungi by proper conditions of air, moisture, and temperature until the major portion of the cellulose has been consumed, then grinding the residu in water to fluid consistency;

WORTH C. GOSS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS OTHER REFERENCES Walker et al.: Biochem. Jr. 32-43 (1938).

Prescott and Dunn: Indust. Microbiol, 1st ed.,

'pages 298 to 300.

Claims (2)

1. AN ARTICLE OF MANUFACTURE COMPRISING A COMPRESSED MIXTURE, UNIFIED BY HEAT AND PRESSURE TO FORM A LUMBER PRODUCT; SAID MIXTURE COMPRISING LIGNO-CELLULOSIC FIBERS IN PREDOMINATING AMOUNT, AND A BONDING AGENT OF WET GROUND BROWN ROTTED WOOD CONTAINING FROM 1% TO 5% OF ACETIC ACID.

3. THE METHOD OF MAKING A GLUE FORMING MATERIAL FROM WOOD, COMPRISING GRINDING TOGETHER A MIXTURE OF WOOD AND CELLULOSE CONSUMING FUNGI, ADJUSTING THE PH OF THE MIXTURE TO ACID, CAUSING INCUBATION OF THE FUNGI BY PROPER CONDITIONS OF AIR, MOISTURE, AND TEMPERATURE UNTIL THE MAJOR PORTION OF THE CELLULOSE HAS BEEN CONSUMED, THEN GRINDING THE RESIDUE IN WATER TO FLUID CONSISTENCY.