Process of woody solid material connection cellulogic.

The present invention relates to the solid lignocellulosic materials joining assembly, particularly wood.

The binding of lignocellulosic materials such as wood is widely used commercially, for example as in the case of the manufacture of plywood and panels from wood particles. The present commercial methods employ bonding adhesives, such as the urea formaldehyde or phenol, which are spread or applied in any other manner on the material surface and penetrate the wood structure, so that the adhesion is produced by glue.

Methods for obtaining such a link

by means of chemical reaction between reactants and the wood itself have been proposed, but they have not been accepted commercially. This is how the patents ü,3. 2.495.043 trade name Willey and other 2.639, 994 and Wilson's suggest the wood treatment by acid, followed by pressing. Neither method does not give satisfactory results, it is to say a bond having a strength sufficient, perhaps because under any ' reasonable pressure, it is to say a pressure under which the cellular structure of the wood is not destroyed, only a portion of the surfaces to be bonded comes into contact, by suits the character irregular and cellular wood surface.

The acids have a hydrolytic action on the cellulose of wood and cause, as a result, a permanently reduced resistance. I. wood as well as proceeding, during 15 minutes in an autoclave, in the presence of hydrochloric acid at a pressure of 0.5 bar which corresponds to 9 the m 22 obtains simple sugar year wood. The AES hydrolysis carbohydrates wood in sugars results in a significant loss of resistance because past the partial transformation of a TES ûyâr&carbon sugars, carbohydrates not of HY ;. V-jlysls are highly depolymerized, thereby MI * pliqua their Eng ^ aestation shorter molecular chain.

It is not possible to minimize such âe hydrolytic degradation to a thin ecash * surface in an attempt to create a " bonding layer **, without affecting the adjacent layers.

These are always ^ - at least partially degraded, resulting in a significant decrease in the resistance of the " wood.

Similarly, U.S. Patent 2.204.384 on behalf Salisbury

5 does not provide a strong connection to hot or cold water.

Eieux, the contact adhesive is applied cold, starch and: sucrose are stabilized by nonvolatile acids mixed; at moderate temperatures, and then cooled for

Water-soluble glue|in powdery form 10 which is then diluted in water before use.

' Discovery of the invention

In one aspect, the invention is embodied provides each method allowing binding materials

' 5 solid lignocellulosic, includes forming the surface of the woody cellulosic material, and preferably in the form of a layer■, of one or more sugars or starches or mixtures thereof and a catalyst capable of converting such sugars and starches and pressing together the

oS surfaces of the material to pipeline elevated temperature and pH such as■hydrolytic degradation of the wood is avoided, so as to obtain a water tight connection.

; the method of the invention can be applied to the

25 e manufacture of laminates, plywood and compound products from wood particles without using conventional adhesives. Any woody cellulosic material may be glued by means of the method in question, irrespective of their dimensions and shapes.

: 0 The binding is believed promotional announcements by chemical conversion of sugars and starches that are applied to the surface of the wood and possibly by a combination of their reaction products with the lignin of the wood.

the chemical reactions caused by the buffered system 3 binding corresponding to the invention in question have not been fully elucidated and the applicant does not wish to be attached by any particular theory. However, . theoretically, more i O system reagents can be performed with both simultaneously causes, such■depolymerization sugars and starches, dehydrating the monosaccharoses compounds furan derivatives, condensation monomers furan with lignin or other phenolic compounds present in the wood, or therebetween.

A salient facts of the subject invention, which distinguishes methods based on the hydrolysis of carbohydrates of the wood, is that the sugars and starches can be converted into a solid, water-insoluble or a condensed including phenolic wood, without the use of strong acids that cause hydrolysis of the wood at the expense of the force thereof. The simple sugars need not be hydrolyzed; di-sucrose is readily hydrolyzed to simple sugars to low concentrations of hydrogen ions, ammonium ions and other compounds such as 1' amid formic dimethylated. The starch is hydrolyzed in hot water. A subsequent transformation into a solid elementary sugars water insoluble, occurs at a pH much higher, which can be obtained without the use of acids, so that the wood does not undergo hydrolytic effect. The result is that no wood degradation takes place and that the total resistance of the wood can be used. In addition, SAL sugars and starches when applied to the surfaces of the wood that it is desired to bind advantageously provide a continuous film on the surface, by filling the interstices and providing a degree of binding greater than that achieved with the methods based on the hydrolysis of wood.

It was found that the strength of bonds formed between the wood pieces from the invention in question is at least comparable to the strength of the bonds had reached by means of the glues used heretofore. In addition, the hurdle is sealed.

Better ways of carrying out the invention

It is sufficient for the manufacture of plywood covering an area. a veneer of wood per ion carrier, year general liquid, containing sugars and/or starches as well as catalyst, and m. M.ttant this surface in contact with a surface of another revised manual&DS which may, or may not, have a coating of the binder composition such that there is a binding compound of the interfacial lay down between the surfaces to be joined, and then pressing at a high temperature, for a time sufficient in a conventional press, so as to obtain 5 the link by means of the conversion reaction. Similarly, different forms of wood particles coated by the compound binding - - can be pressed in the same manner to produce respective boards.

Alternatively, the liquid composition containing " 0 sugars and/or starches with a catalyst may be heated for 30 to 120 minutes at temperatures between 100 and 300 °c, before application to the material to be bonded, in order to transform the sugars and starches in intermediates furan derivatives. Of hot metal can be

5 applied to the surface of the wood in the same way that a composition which is not heated, the application being followed by hot pressing a time sufficient to obtain binding, the use of the composition can be advantageous in hot event. reduced pressing durations are required.

0 In some cases, it may be advantageous to expose the veneer or wood particles coated with the liquid binder composition-Vine elevated temperature, for a short period prior to pressing. Such a preheating causes a chemical transformation partial sugars and starches, which small raGcour: 5■ cIRs the duration of the pressing or lower the temperature of urged # required. Preheating temperatures up to about 3oo⁰ G can be used for a period of up to about 60 min.

It was found that the catalyst content, the tempera? 0 ation pressing and the pressing time can be minimized while the binding properties are enhanced if 1®sugar mixture is precooked starches - - catalysts, as well as described above, prior to application to the surface of the wood, or if the wood surface covered by the mixture is

-5 dried prior to pressing, so as to evaporate the liquid carrier of the binder composition. This results in an acceleration of the chemical conversion of carbohydrates to a water-insoluble solid.

R

The binder composition can include a carrier liquid which does not react with the woody cellulosic material, such as water, ethyl alcohol and other solvents. The amount of support contained in the binder composition is simply that which is sufficient to yield a composition which can be readily handled and applied desirably and in desired amount on the wood. jSn general, vapors from the carrier can easily escape from the press unsealed during the pressing operation. Mixtures of different sugars and starches can be used in a carrier as well as mixtures of different catalysts.

The mixture may also contain other chemical reagents, capable of affecting the binding reaction, i.e. agents accelerators or retarders of the response to the sugars and starches participate, plasticizing agents or cross-linking, according to the reaction conditions which can vary widely. Such reagents can be incorporated in the desired quantities in the liquid medium of the sugars and/or starches as well as with the catalysts. As exempies of reactants capable of accelerating the reaction, can be briefly mentioned the glycol ethylenic, furfuryl alcohol, amines in general, e.g. éthyliaque, n-propyl amine, cetyl amine, diethyl amine, ethyl methyl amine, diphenyl amine, triethyl amine, aniline derivatives, and the like, as well as amine salts, e.g. ammonicométhyle chloride, bromide, chloride ammonicodiméthylique, nitrate-ammonicodimêthylique, monoajniné ethanol, n-phenyl diamine derivatives, polyvinyl chloride? : t further.

The content useful in accelerators in ccmposition binder varies' déquiu wide range and a large no.:; IREs of factors including the activity of the accelerator wrriculi and its cost price, therein comprising ccnsid-to-'raticr.

important from the viewpoint of the production of an economical product. (However, the. content accelerator quark in general comrrise also falls at or about 2 * # of the sugar content and starches and jusç>: * to 30# thereof, remaining as ha ' cituellement ^ in the range of about 4 - 10 $of the, sugar content and gjniâons.

The application of excessive amounts of sugars and starches on the surface of the wood does not affect eêfieacité link, but is not economical. It is simply necessary to have enough carbohydrate and catalyst for effecting=the binding reaction in a_I pressed under pressure and heating. The minimum amounts of carbohydrates and catalyst required vary according to the pH of the wood sugars and starches, and the reactivity of the species sugars and starches, the water content of the wood, the desired reaction rate and other facsimile -

' 0 with widely.

There are wood industries of procedures in which low molecular weight sugars are formed unintentionally from lignocellulosic materials.

For example, during the groundwood, high steam

' 5 pressure is often used to plasticize the wood before grind rafineuses. A high steam pressure causes a partial hydrolysis of the hemicellulose sugars.

During current operations, these sugars are separated from the fiber by washing because they have been found to be harmful

'O for binding that uses common conventional resins.

The sugars à.bas molecular weight present in the fiber can be ' used according to the invention in question, for connection, so that it is not necessary to add sugars, but only the catalyst and, if required, the 25 alkaline material buffer. Likewise, the sugar cane bagasse is used to make fibreboard and the sugarcane bagasse contains about 8 residual sugars that can be used to glue the wood with the invention in question.

the content optimum sugars and starches will vary according to 30, 1' gasoline wood, the reactivity or other properties of the sugars and starches used, the roughness of the surface of the wood to relieve pressing conditions, keeping in mind that the amount of binder composition applied should be sufficient to fill the cellular cavities which open

35■are present on the surface of the wood, thereby increasing the contact surface between the surfaces of adjacent wooden and improving substantially the adhesion. In the case of a link between 7 u6bc4

veneers, is it sufficient to apply a film of the composition ., which can be conveniently carried out. means of a brush, a spray device or a roller. A typical example of an amount of the binder composition which can be employed will deliver between 2 and 32 g of sugar and starch by 1000 cm surface. Can be deduced from the above that the large range Da are sugars and starches can be used, comprising mono bag tank monosaccharide s and disaccharoses of, for example: the mannose, glucose level, maltodextrins, sucrose; starches such as amynose and amylopectin, dextrin, wheat flour or corn; molasses difféi ' ontractor. origins and mixtures of sugars and starches, the méla3 - " its inexpensive represent an alluring prospect.

the catalysts that may be used include the dimethyl formiamide with iodine, the sulfoxide dimetlylé, propylene oxide with ethylene glucol and zinc chloride, both organic salts that minerals, such as ammonium chloride, aluminum chloride, ammonium nitrate, sodium nitrate, potassium nitrate, ammonium sulfate, potassium tartrate, sodium phosphate, calcium phosphate, sodium sulfate, zinc chloride, phosphate diammonié, superphosphate and others. Preferred salts of sodium and amonïum. The nitrates and phospahtes are most effective and the most economical. Phosphates provide in addition to the catalytic transformation of sugar and starch a wood treatment to protect to some degree against fire.

The content of catalyst present is generally between about 1 and 50 f." by weight, based on the sugars and starches, and especially in cases where. seeking a high flame-retardant deçré ; degeneration, it is up to about 100 or more ηη; ¾. The preferred amount depends on the identity of sucrau had starches and the type of catalyst. Da and it is desirable to maintain the minimum required catalyst used for the catalysis of the ' transformation of sugar and starch year composed derived furenuainsx their polymerization. An undue amount of catalyst " without buffering, may interfere with the resistance of the wood after a long period of time. Transforming polyalriques starches, such as corn starch pomma of Energy Magnetism Converter,

■compounds furan derivatives requires a catalyst content uialc 'EU' slightly higher than that required by elementary sugars, such as glucose or sucrose, for a given reaction rate.

It has now been found that the chemical transformation of the sugars and starches should take place at pH values neighboring the natural pH of the wood, it is to say 3,5 - 5.5 and not below 3.0. Basic materials or " buffers¹ ' can, be used to maintain the pH within a desired range. For example, a 20 $0 aqueous solution of ammonium nitrate has a pH of about 6.5. Lorsoue the temperature rises, the ammonium nitrate dissociates and the pH falls to about 2. If the pH of the solution is increased to obtain about 10.5 by addition of base, for example welded or ammonia, the pK obtained at higher temperatures has decreased PK from the wood, so that the pH of the product is between 3.5 and 5.5 depending on the pH of the wood. Can be used to prevent the pH of fall below 3.0 carbonates, such as carbonates or alkaline-earth metal, or amines

THE O - such as those mentioned above, instead of bases. Maintaining the pH of the liquid carrier and final product at appropriate level eliminates any hydrolytic activity, with its resulting decrease of the resistance of the wood, which is of principal importance with regard to the quality of the link.

5 - - A mixture of s course s and starches, such as sucrose and the wheat flour, is used to give rise to a preferred form of the invention. Advantageously with sugars and starches having approximately the same rate of decomposition. Preferred are sugars and starches to elementary^: Gms. polymeric penny as their speed of decomposition is higher. The price and the disponobilité however are probably the most important factors for determining which raw materials used.

The working conditions for the press telling a broad-5 depend on variables such as types of sugars and d * starches, gasoline wood, 1s catalyst type and its content as well as the specifications regarding the product. Thus it is customary in any given system, the lower the temperature is, the more the press long life and vice versa, the pressing temperature should not exceed the carbonizing the. woody cellulosic material and pressure must not exceed that which results in an overshoot of the desired density of the product. The preferred temperature range is HO - 300 °c and the preferred pressure range is 5 - 50 bar. The pressing time required under these conditions is the time required for the heart reaches the temperature at which the chemical transformation of the sugars and starches in a water-insoluble solid occurs, this temperature " set top of between 160 and 212 °c, depending on the type of the catalyst the RS content thereof.

The invention is applicable to any type of binding of wood as well as it is produced during the manufacture of plywood or composite boards. In the manufacture '" compound products, such as boards or fiber, it follows the same method as in the case of manufacturing the plywood except that the particles are covered by the support comprising sugars, starches and catalyst, that can be achieved by means of a spray and a mixture followed by a forming and pressing to the panel. press. The following examples illustrate shapes that can be given to the invention. The percentages are given by weight. Such as I

Yellow pine veneers in 30 cm of 06té and 3? 5 mm thick, with about 4 the I * moisture, were brushed® on both sides with an aqueous solution containing 35 Da are wheat flour, 15 $> sucrose, 2.5# ^ d-ammonium chloride 2.5 the Fe ammonium sulfate, in an amount of 18 g of solution rAAs 900 cm, after application of the solution, the veneers were exposed for 4 minutes at a temperature of 150^than1 0₉ to the suits whereupon the veneers have become completely bags and black " two veneers which were not covered by the binder solution, have been soaked on a face with water, in an amount of about 5 g per 900 cm surface. The veneers to NAF® on wetted e have been laid down against the veneers adjacent both surfaces of which had received the dried binder solution, such that the a-b-f ^ AE wetted were in contact with the AOL are ' lotioned binder dried veneer located therebetween, and whose/

I

rectiis of, / fibers were perpendicular to the VBE1 Receiving is of already. of, ^ ^ AAC âs exterior. the veneers were press ejh carried insteadjH are. during 5 minutes under frpid|bar 14 and after " removed a DEP, the LK (press, the veneers were neck|put forward assembly, such so3it4^/qufils! can be handled without the risk of separating samples prépressés plywood were then pressed during 10 minutes at a temperature ofV, 170 °C the j ^ ith/and under pressure mainly in 14. The plywood was; held

during 72 hours in boiling water, and after eJNfroidissement//therein

/.

/ !"

to, * la ambient temperature, a test at knife conformeAaux to nor -

Stouts britannioues has been performed. these results demonstrate that a monthéf/y VBE1 *

/ // connecting the external model comparable to that which is obtained '

' Y-V.¹

the conventional phenol - formaldehyde adhesive bonding the been V-VBE1 ' ith

obtained.

The II Jxemqle

VBE1

VBE1

Samples in Douglas-fir plywood■have

" tee prepared under the same conditions as in the case/of the exem - VBE1 i-VBE1

iEP-I, except that the veneers have been brushed with a solution

25 containing aqueous iF wheat flour, 20 iF molasses (raw, 2.5 iF ammonium chloride and 2.5 iF ammonium sulfate. Resistance tests are demonstrated a shear strength of about 16 bar, which is comparable to that obtained with similar commodities, using glue formi aldehydethat phenol. the shear strength under conditions

5 wet, after 4 hours in boiling water followed by 24 hours drying °0 53, and then again by 4 hours in water boiling, was about 8 bar.

Such as III

Samples were prepared in pine contreplaoué ' 0 under the same conditions as in the case of 1^? such as I except that instead of veneers dry, wet veneers containing more than 35 Js in humidity have been brushed with an aqueous solution containing 35 iF wheat flour, 15 iF sucrose, 1.5 iF ammonium chloride and 1.5 iF ammonium sulfate, due to

^: 5 of about 18 g of solution per 900 cm in ^ surface. After applying the solution, SAL veneers have " been dried in a dryer conventional during 5 min, temperature 145 - 175^Ü C., following which the surfaces of the veneers have become 11 ■m

completely dry and black. Tests have shown that * after pressing, a quality connection outer was achieved " Example VI

Douglas-fir chips containing about 4 f.> moisture, were sprayed with an aqueous solution containing 35 with fo sucrose, 10 and with fo ammonium nitrate, in a proportion of 25 F. weight of the solution. wood. the particles were dried for 5 watered minutes at a temperature of 155 °c. After drying, the particles had browned and kept a taneur moisture of about 4 a mat was made to advantage, dried particles and transferred on a platen of a urged to hot maintained at 170 °c, where an aggregate panel of 12 mm thickness has been pressed during 10 min. After cooling to room temperature, internal adhesion assays to dry and after 2 hours in boiling water were performed " SAL tests have given a value of the internal adhesion of 8 bar to dry and 2 bar after holding in boiling water.

A particle board particulate pine was prepared under the same conditions as in the case of the example VI, except that the particles were sprayed with a solution containing 30 aF wheat flour, 15 f." sucrose, and 15 aF ammonium nitrate, strength properties were approximately the same as those of the example VI.

Example VI below.

A panel of d * okume conglomerate particles was prepared in the same terms as 1' g. Η, except that the particles were sprayed with a solution containing 60 f.> 8 and raw molasses the Fe ammonium nitrate * strength properties obtained have been approximately equal to those obtained in the case of the example VI.

Example VII.

Particles containing about 6 pine aF humidity have been arroséss with an aqueous solution containing 40 c/o sucrose, 5% and 25 Superphosphast fi of polyolefin chloride in an amount of 15 F. of the solution by weight wood, quenched particles were dried in an oven for 30 minutes at 121 * 0 until about 4 1° moisture. A carpet has been constructed from the dried particle® and transferred to a press assembly © to hot, whose of PLA/îiii © 5 been maintained at 210 °c, where a particle board of 12.7 naan of thickness has been pressed. After cooling to room temperature, 1 * inner adhesion, the swells -! 24 hr after soaking centeredly in cold water and after 2 hours in boiling water were measured. Experiments have given for value 1 * 7.5 bar inner adhesion, swelling in cold water 6 iF and swelling in boiling water 8 iF,

J.&env VIII.

A mixture of sucrose and formiamide dimethyl,, in a ratio of 6:4 by weight with traces of iodine was:

fired for 30 min. A light brown liquid was obtained. A portion of zinc chloride was dissolved in water and added to the mixture sucrose - formiamidediméthilique so that the final amount of the component reaches 6:4:1 parts by weight. The solution, in an amount of 10 iF by weight wood was sprayed onto particles of pine which were then dried for 30 minutes in an oven at 121 °c, to obtain 4 F. moisture. A panel has been formed from the dried particles and transferred into a press having platinum was maintained at 210 °c, and where. a particle board of 12.7 mm thickness was pressed for about 10 min.

A particle board was prepared according to the method described in the example VIII by using 10 iF a solution consisting of sucrose, dimethyl sulfoxide and zinc chloride, in the proportion of 6:6: 1 by weight.

x-üxemple

A particle board was prepared according to the method described in the example VIII., using 10 iF by weight wood of a solution containing sucrose, the glyool ethylinic, ■of 1' propylene oxide and zinc chloride, in the proportion of 6:3:1:7:1. Propylene oxide has been added to the cooked mixture of sucrose, ethylene glycol dimethacrylate and zinc chloride, after cooling to room temperature. Chipboard prepared by the methods described in the examples VIII to X-s-d-<had good properties and were sealed to boiling water,

■i.e. X

The pressing time and the pressure corresponding to the ' produce chipboard according to the invention in question may be the R édT3 " - I-: ΐΗΤ - ΐ α, -, - n-FWD νν + ·~ 1 - /

M3

or melted instead of a solution, the aluminum chloride

; anhydrous either alone, or with other catalysts and suppri "¹ .are the liquid carrier. Aluminum chloride, or ^ of AlCl.

AlgClg " is marketed as powder.

a - in wafer processing application of the lay•

A composition comprising 87 - 97 aF sucrose,

2.8 aF aluminum chloride and 1 - 5 f." ethylene glycol is thoroughly mixed. A small amount of glycol ethylenic, OHCHgGHgOH, is used to achieve a more homogenous distribution of ammonium chloride in the sucrose and accelerate the transformation reactions. The content of aluminum chloride corresponding to a particular wood will vary according gasoline SAL differences in the chemical composition of the wood.

The mixture sucrose - aluminum chloride is incorporated into wood particles so as to obtain a uniform distribution of sucrose to the surface of the particles.

The dampness of the wood must be less than 5 $, since more humidity is low, the slower the rate of reaction is high.

II can be advantageous to mix the powdered sucrose-aluminum chloride, hot particles from the dryer to advantage exile.

Powder particles coated with sucrose -

. aluminum chloride can be pressed into panels without pre -

•heating. The powder being slightly wet, achieves good adhesion to wood particles, so that no observable accumulation of powder on the bottom membrane * has the pressing temperature " sucrose is transformed year a liquid which plasticizes the wood, so that pressures infsbrieures are sufficient, to obtain the final compression of the mat agglomerated.

Results obtained using the method of applying the powder under a pressure of 25 bar are presented in table 1" below:

Results obtained with sucrose sprayed

O

aF wood: mm.

MPET. Duration

O Removal of mercury pressing eras

C. minutes.

Density

Adhesion

Int..

Bar

Swelling *

Ai=aluminum chloride, ethylene-glycol PGCs=

THE L 15' χ, ·χ;

3. MJ3THODJ3S di3 GHüïïïWî -!

A composition containing 95" 99 iF. sucrose

1 - 5 and the mth anhydrous aluminum chloride is thoroughly mixed.

the mixture sucrose-aluminum chloride is heated while being continuously agitated, until the sucrose is turned into a black liquid viscous; 100 g of a composition containing 98.5 iF sucrose and 1.5 iF aluminum chloride is converted into about 3 minutes in a 1" black in a quids of Be expensive on a hot plate.

Sucrose black, hot molten and is applied as an adhesive on wood particles, by spraying or friction (method now ' BMIB). The glycol ethylene can be " used if needed to adjust viscosity. The applicator device must be maintained at the highest temperature, because the sucrose melt is liquid than when it is hot. It has been found that the addition of ammonium nitrate to sucrose melt and hot, before applying to the wood, promotes reaction of the season.

Particles sprinkled molten sucrose may be agglomerated into panels, without prior drying. . As long as the particles are sprinkled hot, molten sucrose provides a good anchorage, so that the prepressing produces a mat particles well prépressées. Sucrose melt becomes very viscous, almost solid, at cooling takes place, the resulting solid is heated, such as the natural * it again become liquid again. It is advantageous to apply the hot liquid to hot particles, from the. dryer to particles.

Results obtained by applying the heating method are presented in table 2, below?

Table 2 results obtained with sucrose molten

σ ·&SSULTATS - DSS's talk07 ΜΜΤ ΡΒDS1 * ^ XüJBPiû¹ ZI ARE

the anhydrous aluminum chloride was found to be

a catalyst effective with sucrose powder or molten * the need for pre-drying wood particles before drying has been eliminated and the pressures and durations were substantially decreased press, the pressing time is dependent on the catalyst content and water particles. The greater the catalyst content is low, the greater the binding reaction occurs rapidly, the water content of the system reactive I, set top substantially reduced when using sucrose powder or molten * incorporation at éthyléniquo glycol system, confectioneries in place of water, in order to achieve a better distribution of chloride through the powdery sucrose, or adjust the viscosity of the molten sucrose, has proved beneficial. It is likely that the glycol ' ethylenic improves the transfer the DS heat in the interior of the panel. The solids content aluminum should be maintained at the lowest possible level, in view of the varieties of wood and time pressagB desired.

It has been discovered that a panel of 19 mm thickness being dried for 6 minutes at 190 °0, has a degree which allows it to be removed from the press. Although the inner adhesion has reached its peak development, the binding reaction at the center of the panel is not complete, as the tests after holding in boiling water the prove. If additional heating is ensured, for example by means of a hot staking panels exiting the press, the central portion of the panel also becomes sealed in all boiling water_C. the samples no. β-7 and b-9 of table 2 were pressed during 6 (samples B 7) and 8 (samples B 9) min followed by a holding without pressure in Is. press, during the IQ and 7 minutes, respectively, the centered portion of each sample has become completely dry.

the sucrose content that is to be used to obtain an H © Ra of® binding particles depends on the geometry of the IIa e same "! has content of 10, 5" by weight wood was chosen because the sawdust Redwood employed was very thin, with a large developed surface. Contents of between 4 and 10 $- will be appropriate core the case of the commercial particles * 3■chloride content for use will vary lu-to-taninium with the varieties of wood. 1 © - percentages between about 0.2 and 1.0 weight wood appear realistic, the chloride content ' aluminum must be found by means of routine tests in Y each particular case essences, ammonium nitrate content of between about 0.5 and 4 $appears realistic, yet;

it may vary somewhat according to the particular gasolines. ;

Thick molasses will react in the same manner I than sucrose with aluminum chloride, ■provided that the water content of the molasses is reduced before incorporating aluminum chloride. ;

Additional tests, performed with plywood showed that the use of aluminum chloride instead of ammonium sulfate, as a catalyst, in compositions for plywood accelerates the binding reaction.

5 - Example XII.

Studies concerning relationships between temperature and time, processing, as well as the exploration of the possibilities of d? acceleration of the link relation have been executed. Samples chipboard of 2.5 mm thickness were prepared at temperatures of 126, 148, 158 and 176 °0, for the purpose of determining the minimum pressing at different temperatures. 24 Hours of swelling after soaking in water cold and after 2 hours immersion in boiling water, has been used as criterion for the purpose of interventions; mining if the binding reaction is complete or not. The

•specific samples was located about 0,730. Particles Douglas-pine, Pinus lambertiana, and cedar incaace were used in this study. The results presented in table 3 web allow for following the conclusion:

to the temperature of 175 °c, the binding reaction

is complete after d * 1 min, 160 °c to 2.5 to 5 min of,

0 to 150 ο· 5 to 10 minutes to die, to 140 °c for 10 to 30 minutes and to 130^I The g ' of 15 to 60 min, as gasoline. It seems likely! that the pH of the wood has an influence on the reaction time.

TABLE 3

24 Hr cold cedar: 8.7 9.3 13.0 12.2 s, 9 13.6 13.0 sec. 11.2 6.95 11.8 11.1 36.5 15.0 11.18, Encance2 hr: 15.5 24.4 15.2 13.3 13.4: '

L _. It VO " CK from the j * ; Example Χ Σ ΐ 1

j of wood particles having a shape of wood fiber produced according to the method thermonécanique, as APs -.

in the case of the defibrator pliquéAsplund with humidity of

5, 6 were sprayed with an aqueous solution containing 36 $

^; sucrose and 10 iF ammonium nitrate, at the rate of 15 the I " ; weight of fiber exiting the oven. After air drying VBE1 to achieve a moisture content of approximately 8 f.?, the carpet fiber was shaped by hand and has served to press a panel

■? 0 conglomerate of 6.5 mm thick, by pressing during 3 - 0, 5

^; min, under a pressure of 38 - 10 bar, at a temperature of 232 °c. the panel showed the following properties:

specific 1.5 " modulus of rupture 2.94/mm in the K² ; modulated elastic

W w

The K/mm in•371; the K/mm in inner adhesion 0.12; swelling after soluble TREM ' 5 page during 24 hours in water 12# 2 and after 24.5 hours in boiling water

VBE1JSxemple-XIV

^J A composite panel was prepared according to the method

the I described in the example xiii, with the exceptions indicated below 20^;Y below and using the wood fibers:

(has) in a first sample, nitrate LFDA Relief was¹ buffered to provide a pH equal to 10.5 by addition of oxygenated water;

(d) in a second sample, nitrate - LFDA

25; relief has been replaced by a same amount of sodium nitrate

(i) in a third sample, nitrate LFDA ™^! relief was replaced by an equal quantity of potassium nitrate

(d.) in a fourth sample, nitrate LFDA ™: Relief was replaced by an equal quantity of Superphosphast

30^: ammonium was replaced by an equal quantity of Superphosphast

(i) and in a fifth sample, the ammonium nitrate has been replaced by a same, amount of phosphate

The I diammonié■

I in pannaanx showed comparable properties 35i! to those that were attached to the panels. which have been described;_; in the example hlL the buffering was used to adjust the pH at

; a same level as the natural pu hois which is between :■! 3 "5 and 5.5" the Buff ' a-assge e^? aST testing has proved advantageous in the case of j j of ammonium nitrate, May ;? unnecessary in the case of potassium nitrate and sodium. When the quantities are those indicated in the example XIII., superphosphate ' and the

•! the phosphate diammonié have not he and care D.⁹ i TREs buffered. If the. amounts superphosphate and sulfate, diammonié are more

' 5 important, which may be desirable if it is desired to provide a higher level of flame retardant age, buffering can be advantageous.

one examination of the samples shows that the addition

<a small amount of sugar and/or starch as well as the Advanced-to-10 lysor, preferably a salt as has been indicated, the surfaces to be bonded produces binding under the influence of temperature and pressure, the bond strength is comparable to that which is obtained ^ using conventional adhesives and the bonds are resistant to the action of water, one such system showed 15^; an important economic advantage because the price of the sugars and starches usable is carried out only in about■§■1/9 to price the most commonly used adhesives such as adhesives based on formaldehyde urea or péhnol.

It will appear obvious to those familiar 2d■with technically sound, that many modifications

|may be performed without departing from the scope of the invention and! it is not to be considered limited to j daiis denoted in the specification.

the L