US2271212A - Treatment of plant growths - Google Patents

Description

' be set forth in part hereinafter and in part will Patented Jan. 27, 1942' UNITED STATES PATENT. OFFICE I 2,271,212 v No Drawing. Application January'11, 1940, 8e-

rial No. 313,343. In Canada March 9, 193'! 5 Claims. (o 21-50) timber with, carbohydrate solutions which penetrate the cells of the timber, displacing the natural liquid and fermentabie constituents and introducing agents which act as preservatives and to stabilize and otherwise affect the: wood.

Objects and advantages ofthe invention will be obvious herefrom, or may be learned by practice with the invention, the same being realized and attained by means of the instrumentalities and combinations pointed out in the appended claims.

The invention consists in thenovel parts, con

'structions, arrangements, combinations and improvements' herein described.

This application is /a continuation in part of.

ment of freshly felled green timber in log form,

preferably with the bark still on the log and with the" natural saps, extraneous matters, resins. Juices and other liquid and volatile components of, the living tree still present and unchanged in the wood. The invention comprises certain novel steps and technique and also certain novel combinations and solutions of ingredients where'- by preservative and wood-penetrating materials, whichheretofore have been introduced into the wood only by the immersion process, and even then unsatisfactorily, may be. introduced with much greater-rapidity andmore effectively di's-.

tributed through the wood by endwise or axial penetration of the unbarked log. 2

In previously known processes, attempts at preservation .and other preparation of timber have been made by the use of solutionscom.

taining true. or more sugar materials which are known to penetrate the cellsof the wood and displace the natural contents thereof by osmotic action.) The action on wood of the sugar soluwood fibers and cells are displaced by a carbohydrate, particularly one of the sugars. Heretofore treatment of wood with such sugar solutions,

has been attempted by the immersion process; that is, marked logs or sawn lumber boards were submerged in a tank containing the sugar solution' and penetration of the wood was eflected by a prolonged cooking action in which the solution was raised to a high temperature, and usually to the boiling point. By gradually raising the temperature and carrying out the treatment over several hours a fairly satisfactory penetration of -the wood by the carbohydrate solution was eflected. However, the-rate and extent of penetration depend upon the thickness of the board as well as the time of treatment as the solution enters from all surfaces of the immersed wood, and the cost, time consumption and non-uniform results have prevented successful commercial exploitation of such solutions with the immersion process.

The present invention eifects much more complete, rapid and uniform penetration of the wood cells and fibers by sugar solutions, causing the treating materials to penetrate and travel rapidly and thoroughly from one'end to the other of a freshly felled log. Such axial application and penetration of sugar solutions has never been successfully practiced heretofore and aprimary object of the invention is to render such use of sugar solutions commercially practicable and more eflective and cheaper than methods previously used with such solutions. Whereas in the prior methods of applying sugar solutions to wood by immersion, all surfaces of the wood were simultaneously subjected to the penetrating action of the-solution, in the present invention,

the solution enters at one end only of the log,

the opposite end being left free and at atmospheric pressure. Hence the solution enters the log rapidly without opp sition from counterpressures of solution entering at other points and thereby the full benefit of the peculiar penetratin'g action of 'the sugar solution may be en- Joyed. By the present process the. penetration and distribution of the treating materials is very rapid and far more thorough than any prior process; moreover, the treatment is carried out at temperatures substantially those of the log itself and without any boiling or cooking action, so that weakening and changing of the wood ilbers by high'temperatures isavoided. The log tions in general is known tozbe that'of asimilar acting on a similar wherein the. natural sugar solutions and other fermentable contents of the t6 -rectly immediately to requires and receives no preparation prior to the treatment as the treatingflution is applied ,di-

e nd 1 e 0 a freshly able substances of the wood automatically issue 3 from one end of the log as they are displaced by the entry of the treating solution at the other.

.Said extractive materials are removed in their natural'state and unaffected by high temperatures or chemical action.

As will be clear, one object of the invention is to improve and speed up the operation of the socalled Boucherie method of wood impregnation. While the present invention is similar in its physical technique to that of the Boucherie process of end-for-end log impregnation, the rapidity and thoroughness of penetration of the log by my invention are many times greater than that effected by the Boucherie method.

Another object of the invention is to utilize sugar solutions of much lower concentrations than those heretofore used in the art. Whereas in the prior practice of impregnation of wood by sugar solutions through immersion, it'has been customary to use sugar solutions of the order of of sugar or higher, the present invention will achieve many of its beneficial effects by use of a very low concentration of sugar on the order of 5% and as low as in some cases. Moreover, by using the end-for-end technique of impregnation, the distribution of the low concentration sugar solution is virtually uniform radially of the log, whereas in theimmersion process, a much higher concentration of sugar is found at the surface than at the interior of the tion but not restrictive thereof. 7

Referring now in detail to the present preferred embodiment of the, invention, the process and solutions used therewith are preferably applied to thebutt end of a freshly felled green log, from which the bark has 'not been removed and the cambium or inner bark is preferably intact. By freshly felled it is intended to define a log in which the natural sugars and other protoplasmic substances have not become crystallized or hardened by drying. Thus logs may be treated at a considerable time after they have been ielledprovided drying and the natural crystallization effect'has not progressed to the point where osmotic penetration of the cell walls has become impossible or greatly impaired. Such drying may be prevented for a; considerable time by maintaining the log in a pond or moist atmosphere.

The treating solutions used with the present process are of the ty'pehaving a sugar base, and one which-has the natural capacity of entering into the cells and fibers of the wood by osmotic action; The nature, constituency and action of such solutions will be detailed hereinafter. 'In

the process a solution of the nature indicated is applied to one end (preferably the butt) of the fresh log and a supply thereof is maintained against-said end while the solution enters and travels throughout the length of the log. The

entry and travel of the solution through the log is facilitated bysupplying the solution at the exposed end of the log under a relatively low hydraulic pressure, the usual pressure being about five or six pounds per square inch and rarely exceeding forty. In practice the solution is confined about the treated end of the log by a hollow cap or header which fits tightly over the end of the log, being hermetically sealed thereto by a suitable gasket. The bark is preferably removed near the end and the woodmay be smoothed or chamfered to provide an even fit for the gasket and header. The opposite face of the cap or header is connected by a pipe or hose to a source of the solution under pressure, a pump or the like of controllable capacity being preferably used in practice. Apparatus of the general type described is well known in the art cylinder of the ring growth of the tree appears to transmit the solution more or less independently of the others, there being little or no radial circulation therebetween; Also the solution acts to lubricate or partially dissolve the bond between the cambium and bark as the latter can be very readily removed after treatment by a simple peeling operation.

As the solution enters and travels through the log it displaces ahead of it the sap and other liquid and soluble constituents of the tree and these extractive materials flow from the opposite end of the log where they may. be collected and utilized as desired. Liquid or moisture is naturally held in the wood in two distinct waysimbibed moisture" in and around the walls of the ,W00d 08 1LS and freemoisture within the cell cavities including the vacuoles and protoplasm. When green wood dries out naturally, the free moisture leaves first, followed by the imbibed moisture. In order to secure a more suitable and stable fiber saturation point inwood the present process removes the free. moisture from the cells and replaces same with the preservative solution which shortly solidifies preventing further absorption into the cells. By the replacement of natural moisture or sap in wood with sugar solution, which with other chemicals acts to dehydrate the wood structure from the inside outwards and perform other desired results including the permanent stabilizing of the contents, the invention practically eliminates shrinkage and swelling or dimensional changes. The sugar solution has the capacity of penetrating (possibly by osmosis) into the -cells and into the vacuoles and 'protoplasm within the cells and displacing the cell sap, organic acids and mineral matter, known as "free moisture or cell cavity water. Also said solution, in traveling through the tree, displaces and flushes outthe imbibed moisture which lies around and between the cell walls. Thus by this removal of imbibed and free moisture because of the chemical reaction of the solution used, the cellulose or wood structure be- 1 comes cleansed of the minor or extraneous components in the wood such as resins, terpenes, fats, nitrogenous organic compounds, tannins, pigments, mineral matter, and'the organic acids,

which all exude from the end of the log opposite to the end at which the solution is supplied. Thus, besides thoroughly cleansing the log, the structure is filled with the solution which performs various functions as desired, depending upon the chemical mixtures used. Such chemicals gain entry into the fiber and cellular structures of the wood through the base sugar solution acting as a vehicle or carrier whereby they are permanently deposited to stabilize, color, fiameproof, or prevent insect attack by toxic agents.

The treatment of the wood with sugaras described has been found to result in a notable incrystallize on the cell wall thereby increasing its structural strength. This increase in strength of the cell wall not only improves the natural strength qualitiesof the wood, but apparently is responsible at least in part for the anti-shrink effect, as the sugar substance is non-volatile and therefore tends to prevent collapse of the cell walls during drying and after the moisture content has been reduced below the critical point, i. e., the elimination of the free moisture. Many of the phenomena exhibited bytheaction of the sugar in entering the log and the characteristics solution travel or flow through the wood is materially reduced and eventually almost stops. As

the wooditself becomes heated at thetreatedend, the fibers swell and the wood attains a congested condition. 1

. Referring now to the preferred constituents and characteristics of the solutions used in penetrating and treating the wood, the process utilizes the known effect of carbohydrate solutions, par- 10 ticularly the sugars, to penetrate and occupy the wood cells and fibers. More particularly, these sugars or sugar substances which have a. low molecular weight and high aptitude for penetrating the wood cells are preferred. Examples of such effective sugars are the mono-saccharides,

such as corn dextrose, commercially known'as 1 hydrol, although sucroses and other di-saccharides may be used-in some cases.

It is diflicult to generalize very far because the '20 preferred sugar varies considerably with respect to the species of wood treated, the kind of treatment and the results desired. The pH of the solution alsovaries. For example, in impregnation of chemicals for the purpose of preservation the solution should be on the acid side, while for preparation ofthe wood for pulping or impregnation with dyes, an alkaline reaction is "preferable.

The following is a classification of sugars/in order'of preference, indicated-by my present experience, but is not restrictive of'the invention:

Com sugars A. The substance which gives the most rapid f the wood after being so treated indicate that penetration (the greatest promoter of osmosis or the sugar molecule (glucose or other mono-saccharide molecule) is adsorbed by the cellulose molecule of the wood.

For ordinary purposes or preservation, stabilization, coloring or the like treatment of the wood, introduction of the solution at the-treated end is maintained until specific gravity tests of the liquid issuing at the free end indicate that the treating solution is issuing therefrom, at full strength.

It has been found in practice that proper control and maintenance of the temperature of the treating solution in fairly definite relation to the temperature of the interior of the-log itself is one of the essential characteristics of the present process. The temperature of the solution should be 'near or slightly higher than that of the interior temperature of the logitself. For example, in treating logs having an interior temperature of approximately 60 degrees F., theatmos phere being about 80 degrees F., a solution temperature of between 80 and 90 degrees R was found very effective. In general it may be stated that the temperature of the solution should be substantially above 40 degrees F. and rarely, if ever, at temperatures substantially higher than said temperatures and pressures being regulated according to the results desired and the particular wood being treated. At'the lower temperatures the sugars and other materials in solution tend to solidify or thicken, while the higher temperatures cause swelling and congestion of thea wood cells and fibers, thereby physically impeding penetration and impregnation of the liquidin the wood structure. At temperatures over 120 whatever the wood penetrating phenomenon may be) is anhydrous or regular cerelose, a corn dextrose. The anhydrous runs 99.8% dextrose, with no mineral content, and .2% water. The regular cerelose is 91.5% dextrose, .5% mineral, and about 8% water. Cerelose, however, lacks the desired wood stabilizing qualities (i. e., prevention of shrinking, warping, etc).

B.For general all-around eifectiveness a 70% ,PCOID. sugar is best. This sugar comprises 70% dextrose'with .85%,mineral substance. It may run-to 17.75% moisture. I

C. Hydrol is the best I have found for general results and 'low price. During the last few years cgmmercial hydrol has varied considerably in dextrose, moisture and ash, which make considerable difference in this work. It is also affected by variations in non-reducing and reducing di-sac-harides, as well as a probable content of about 5% tri-saccharides. I understand that hydrol is taken from the line of anhydrous and cereal sugars being P ocessed from comto produce' alcohol and fermentation products.

D. Another corn sugar I have tested is corn syrup or glucose. While this has about 35% dextrose, its high dextrine content (45%) makes it unsuitable. The Baum reading runs about 41-42.

Cane sugars a fair dextrose result, butieven considering their invert contentof 18%, the ash runs too high 2 (about 14%) organic non-sugars 15% and 'a high moisture 0f'24%.

C. South sea island sugars, such as are used in degrees F. it has been found in practice that the western Canada, are much better than the Beet sugars Beet molasses (discards) work fairly well but might as well be classed in the refinery group as being too high in ash and hence too colloidal in solution. I

I have discovered that, chiefly by maintaining the sugar solution at the relatively normal temperatures indicated above, sugar solutions may be caused to travel with exceeding rapidity through the length of a freshly cut log. For example, in logs of relatively short length up to say 8 feet, I can effect a complete end-for-end penetration of the treating solution at speeds as high as one lineal foot per minute regardless of the diameter of the log. With long logs, the rate of penetration is considerably slower because of the natural resistance from internal hydraulic pressures. However, the improvement in speed of penetration on longer logs as compared with former practice of the Boucherie system in which no sugar solution is used, is also surprisingly high. Whereas, in the Boucheri'e system it is customary to require several hours to penetrate an 8'foot log, I can penetrate the same length log with my process in an equal number of minutes; while I can impregnate a 40 foot pole in say 5 to 8 hours as compared to an equal number of days in the usual practice of the Boucherie process.

As hereinbefore stated, I have made another important discovery in that relatively very low concentrations of sugar in aqueous solutions can be used to penetrate logs rapidly when the logs, temperatures, and pressuresare maintained within the conditions and limits disclosed. Thus an equally rapid and thorough penetration of the solution may be effected with a solution having a sugar content as low as and an'incre'ase in the sugar concentration beyond that point does not materially increase the rapidity and thoroughness of penetration. However, greater quantities of sugar up to say 10% are found to increase the stabilizing or seasoning effects and also the strengthening of the wood. That is,

by loading higher quantities of sugar into the log, I can increase the anti-shrinkage effect and inhibit warping and checking while at the same time raising the structural strength of the wood. Thus if it is desired primarily to use the sugar solution as a vehicle for thorough and rapid introduction and impregnation of a preservative agent such as zinc chloride or other soluble woodpose I have found aluminum sulphate most desirable as it speeds up air seasoning and kiln drying; while imparting a mild toxic and preservative effect to the wood but without any undesirable effects.

The following formula is given as typical of the ranges of ingredients used for various purposes, primarily for the stabilization and'seasoning of wood:

- Per cent Sugar From /2 .to Aluminum sulphate From /2 to 5 Boric acid From to 5 In general the relative proportions of the matetreating agents such as .dyes, toxics or fiameproofing chemicals, sugar solutions as low as will provide the desired vehicle for introduction and distribution of these other chemicals. However, when the primary consideration is the stabilization of the wood and strengthening thereof, higher quantities of sugar up to 10% can be used with benefit. For practical seasoning purposes, an optimum quantity of sugar which willnot be prohibitive in cost yet give a high degree of'strengthening, seasoning and stabilization will be a 4 or 5% solution of sugar.

Other ingredients or chemicals may be added to the solution to give various effects. As stated, the wood preservatives such as zinc chloride or other water soluble salt preservatives,'such as Wolman salts, zinc meta-arsenite, chromated rials used will depend on the result desired and the species of wood being treated, within the general limits indicated hereinabove.

In the foregoing solution the sugar material may be any one of the types of sugars hereinbefore referred to and it will be found that one type of sugar is preferable for one specie of tree, while another sugar is preferable for some other trees. In the above formula the boric acid is found to be helpful in. promotingthe osmotic penetration into and through the wood and it also acts as a mild preservative or toxic. The aluminum sulphate is efiective to dehydrate the wood, reducing thehygroscopic tendencies of-the wood and acting in combination with the sugar to absorb cell moisture and cause the tree to dry from the interior outwardly. It is thereby helpful in obviating kiln drying of the wood and preventing case hardening of the cut wood. It is also effective as a flame repellant and as a mild toxic preservative. A

The foregoing formula may be considered typical for general purposes of impregnation and wood seasoning and is indicative of the use of sugar in the solution as a vehicle to introduce preservative materials and other chemicals. In the same general manner chemicals such as dyes, preferably the aniline group, flame-proofing chemicals, such as di-ammonium phosphate, and in general any other water-soluble substances which may beused to improve the qualities of wood, can be introduced along with the sugar solution as a vehicle. It will be'understood for the purposes of stabilization and strengthening of the wood per se, a simple solution of water and sugar will in itself effect those results, while sap stain and fungus growth will be somewhat impeded by the flushing out and displacement of the fermentable natural liquids and substitution thereof by the relatively sterile sugar solution. Another type of wood treating ingredient which may be introduced by this method comprises the wood pulping agents and similar materials for the easier production of cellulose fiber from the wood. 'Ihedetails of such' treatments are disclosed and claimed in my co-pending application Serial No. 195,961.

A further improvement in the penetrating effects and treatment of the wood may sometimes be eflfected by the inclusion in the saccharide so- Y it has been found that these agents are most helpful in facilitating the formation of the solution especially when dyes or other substances diificult to dissolve are incorporated therein.

Among' the wetting agents which have been found especially effective for many phasesor applications of the process are the substances having the trade namefAlphasol'" or Aerosol, which are esters of sulpho-saturated and unsaturated aliphatic dicarboxylic acids, the preparation and composition thereof being disclosed in United States Patent No. 2,028,091 of January Other wetting agents similarly usable are the compounds having the trade name A eskap which is a mpn'osodium sulphonatev f butyl phenylphenol; Arisket asulphonated alkylated diphenyl; and Ariskene which is a s phonated alkylated oxydiphenyl. Another wett agent similarly usable are the Tergitols', which are solutions of sodium sulphates of the higher synin effecting the solution and penetration and fixation of dyes or coloring matter in wood. When used with basic, vator analine dyes, it brightens the shades and faster'colors result. Cellosolve increases the solubility of the dye in the sugar base, and also isefiective in fixing the dye in the wood. This substance is very effective in penerating the most difficult portions of the wood cells and thereby acts to carry or lead in the other elements of. the solution. It also has a solventaction on the resins, gums and other substances in the wood and to some extent on the cellulose itself thereby improving penetration and also effecting deposition of the dyes and the sugar material itself on the cell wallsand in the fibersof the wood. It is probable that Cellosolve also acts as an emulsifying agent or link between the oils and water, thereby facilitating impregnation and removal of resins, etc.

For the dyeing or coloring of woodin accordance with the invention the following solution has been found effective:

Per cent Sugar I A to 25 Boric a to 5 W tt agent to -1 Dye My, t0 4 Cellosolv A, to

If it is desired to render the wood more flexible or improve the ease of cutting as for veneer manufacture, either tri or diethylene glycol from one-half percent to 2% may-be added to the above solution. In certain cases to speed up the drying action of the wood aluminum sulphate in quantities from A to 5% may also be added to the foregoing formula.

The invention also comprises the application of the. foregoing general principles to the preparation'of wood for rendering it insect proof by the impregnation of toxics; and for introducing flameproofing ingredients to render the wood Furthermore said principlesv of the invention may also be applied to preparanon-combustible.

tion of wood for use in the manufacture of pulp or cellulose material, especially by the introduction of materials which act upon the resins'and lignin in the log thereby to obviate or facilitate scribed but departures may be made therefrom within the scope of the accompanying claims without departing from the principles of the invention and without sacrificing its chief advantages. r

What I claim is: a 1. The process of treating wood which co'mprises applying to the end of afreshly cut green log a sugar solution having osmotic action on the wood and causing said solution to travelthrough the log toward its opposite end while maintaining the temperature of the solution near that of the interior of the log, said log being substantially at air temperature. 2. The process of treating wood which comprises applying to the end ofa freshly cut green log a sugar solution having osmotic action on the wood and causing said solution to travel through the log toward its opposite end whfle maintaining the temperature of the solution be low that which would cause appreciable swelling of the wood fibers and obstruction to penetration of the solution.

3. The process of treating .wood which comprises applying to the end of a freshly cut green log a sugar solution having osmotic action on the wood, said solution containing a surface tension depressant which facilitates formation of the solution and penetration thereof into and through the wood, and causing said solution to travel "through the log toward the opposite end thereof while maintaining the temperature of the solution below that which would cause appreciableswelling of the wood fibers.

4. The process of treating wood which comprises applying to the end of a freshly cut green log an aqueous solution of dextrose, said solution containing a wood-preserving ingredient, maintaining the solution at the point of application at a temperature substantially no, higher than degrees F., maintaining a hydrostatic pressure on said solution against the end of. the log and causing the solution to travel through the log to the opposite-end thereof, thereby displacing natural moisture from the log.

5. The process of treating wood which comprises applying to the end of a freshly cut green log an aqueous solution of monosaccharide sugar, said solution containing less than ten percent of said sugar, maintaining the solution at the point of application at a temperature substantially no higher than 120 degrees F., maintaining a hydrostatic pressure on said solution against the end of the log and causing the solution to travel through the log to the opposite end thereof, thereby displacing natural moisture from the log.

CHARLES G. TENGER.