AU729387B2 - Method of treating wood and the wood - Google Patents

Description

1

AUSTRALIA

Patents Act 1990 EIWA CO., LTD *5 S S

S

A.

S. S. S

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Invention Title.

Method of treating wood and the wood The following statement is a full description of this invention including the best method of performing it known to us:- Field of the Invention: This invention consists in a technique enabling easy extraction of oils and fats from wood, speeding up drying of wood, and also enabling e asier application of dyeing and preservative processing to wood dependen tly on fumigation in which wood is subjected to permeation of gas theret hrough instead of immersion thereof into a chemical solution, and oils a nd fats closing the pit part of wood, each pit closing the cell of wood, are dissolved so that said pit of wood may be opened, and a wood treate *d by said process.

S: Prior Art: As methods of processing wood while immersing wood into halogenated hydrocarbon solution, known are such arts as disclosed in the U.S.Paten ts, Nos. 3,685,959, 3,948, 802, 3, 959, 529, and 3, 967, 011.

I5 However, according to the prior arts as above, wood is directly imm ersed into a halogenated hydrocarbon solution and, as a result of too st rong power of said solution as solvent, the surface structure of wood is decomposed as if dissolved, whereby further permeation of halogenated h ydrocarbon solution into the inner part of wood stops and removal of oil M) s and fats is impossible.

Accordingly, when injecting preservatives, dyestuff, and resin into wood processed by the prior art, permeation of these chemicals is effec tive only at the outer part of the wood body and incapable of extending to the inner part.

Summary of the Invention This invention, in connection with the conventional technique as ab ove, enables processing of wood by adding surfactant solution to said ha logenated hydrocarbon solution, or halogenated hydrocarbon solution and water, or mixture solution of halogenated hydrocarbon solution and water so that sharpness in dissolution of resin which closes the pit part of wood may be increased, luster of processed wood be improved, and proces sing of wood with generation be possible, and a wood treated by these pr ocess.

Brief Description of the Drawings 1O Fig. 1 is a view showing the fundamental composition of a method of and apparatus for processing wood according to this invention; Fig. 2 is a view showing processes and steps in the method of wood processing by means of indication as ON and OFF of the valve mechanism; o 15 Fig. 3 is a side view of a part including a processing tank T, lid 22, and wood-mounting table 26; Fig. 4 is a side view of the tank T to which the lid 22 is applied to the tank for closure thereof; Fig. 5 is a front view of the lid 22; Fig. 6 is a sectional front view of the processing tank T; Fig. 7 is a front view showing a state in which wood W is mounted o n the wood-mounting table 26; Fig. 8 is a perspective view of pits 30 of the needle-leaf tree; Fig. 9 is a sectional view of a pit 30 as above; and Fig. 10 is a sectional view of the inner part of the processing tan k T in operation of processing.

Description of the Preferred Embodiment In an embodiment of the invention as shown hereunder, methylene chl oride solvent solution is disclosed as a halogenated hydrocarbon solutio n, however, the use of other kinds of halogenated hydrocarbon solution m ay provide the same result. For example, trichloroethylene, tetrachloro ethylene, or 111-trichloroethylene suffices.

Further, an embodiment in which water and surfactant solution are a dded to the methylene chloride solution is shown, however, effects of th is invention are exhibited even when halogenated hydrocarbon solution on ly or methylene chloride solvent solution only is used, or in a state in which water is added to methylene chloride solution, or methylene chlor t0 ide solvent solution, water, and surfactant solution are mixed togather.

On the other hand, it has been found that the highest effect can be obtained when water and surfactant solution are added to methylene chlo ride solvent solution. Even when halogenated hydrocarbon solution only 15 is used, fat removal effect is exhibited, however, addition of water the reto reduces impairment to the surface of wood caused by chlorine gas.

When mixing halogenated hydrocarbon solution or methylene chloride sulve nt solution with water and surfactant solution, sharpness in fat removal is increased by a surfactant solution, thereby oils and fats removal ef .O fect being increased.

An embodiment of the invention will be described hereunder. Methyl ene chloride is a substance expressed by a chemical formula as CH 2 Cl 2 an d has a molecular weight of 84.93. This substance is sometimes called d ischloromethane or methylene chloride in addition to the general name as methylene chloride. Its boiling point and melting point are 40.4 C and -96.8 C, respectively. Methylene chloride decompose when it is heated over 130 0

C.

Surfactants are classified into anionic, cationic, nonionic, and am photeric ones. Anionic surfactants are alkyl sodium sulfate, amide sodi um sulfate, secondary alkyl sodium sulfate, alkyl sodium sulfonate, amid e sodium sulfonate, alkylallyl sodium sulfate, and alkyl naphtalene sodi um sulfate.

Cationic surfactants are amine acetate salt, alkyl trimethyl ammoni um chloride, dialkyl methyl ammonium chloride, alkyl pyridium halogenide and alkyl dimethyl benzyl ammonium chloride.

As amphoteric surfactants, there are carboxylic acid type, sulfonic acid type, and sulfate type ones. In nonionic surfactants, polyoxyethy lene alkylphenol, polyoxyethylene fatty alcohol, polyoxyethylene fatty a cid, polyoxyethylenic acid amide, polyoxyethylenic fatty amine, and poly propylene glycol are included.

In the method of processing wood according to this invention, with the increase in alkalinity, C12 is liable to be generated and, for preve ntion thereof, polyoxyethylene alkylphenol in alcoholic system, which is 15 nonionic surfactant relatively stable against acid and alkali, is effec tive in this respect. However, for dissolving resin of wood and opeing pits, all kinds of surfactants are effective.

When heating the mixture of three substances as methylene chloride solution, water, and surfactant solution as performed in this invention, gases and compounds that will be described under are generated in addit ion to methylene chloride gas, water vapor, and surfactant gas. Gases a nd compounds referred to above are HCHO, HF, HCI, HBr, NH 3 C12 (a few q uantity), CH 4 CO, C0 2 organic acid, and organic compounds.

Organic acids are phosphoric, citric, pyruvic, malic, succinic, lac tic, formic acetic, levulinic, pyroglutamic, propinic, isobutyric, and i sovaleric acids. Among these organic acids, phospholic acid is effectiv e for development of yellow color and nitric acid as well as succinic ac id is also effective for pink color whereas acetic acid removes color fo r providing whiteness. Chemical actions as above has made it possible t o process such woods as hitherto generally called "red ceder" or "black core" and disliked as low quality one in the market because of color dep th thereof, and to remove reddish color, decolor black core parts, and t urn said wood into high quality one having moderate color and luster.

Organic compounds, when subjected to mass spectrometric analysis wi th gas chromatograph, have been found originating from essential oil as chain saturated hydrocarbon, sesquiterpene, sesquiterpene alcohol contai ned in resin of wood. Such compounds are extracted when resin in wood i s dissolved by methylen chloride and surfactant.

Referring to Figs. 3, 4, 5, 6 and 7, the structure including a proc essing tank T, lid 22, and wood mounting table 26 will be described. Th e processing tank T is constructed to be a long cylindrical pressure ves sel and in view of such degrees of pressure as 50 Torr for deaeration from wood and 200 Torr for recovery of methylene chloride required in th e method of and apparatus for processing wood according to this inventio n, is adapted to endure the abovesaid degrees of pressure.

The lid 22 is disposed in the front side of the vessel and structur ally integral with the wood-mounting table 26. Said table 26 is displac ed on the rail 24 provided in the processing tank T and the lid 22 is mo '0 vable on the rail 24 below the lid supporting part 23 so as to move inte grally with said part 23. Wood W as on object to be processed is mounte d on the wood-mounting table 26 which is withdrawn and advanced integral Ily with said lid 22. In the state that said wood-mounting table has be en thrusted into and retained in the inner space of the processing tank T, pressure is applied to said inner part after the lid 22 closes the pr ocessing tank T hermetically and unmovably. Heating cooling pipes 20 a re arranged on the inner bottom of said processing tank T and, when heat ing is intended, steam having a temperature amounting to 100 and several tens °C is supplied from the boiler B. For cooling, water in the cooli ng water tank 18 is supplied. A mixture solution of methylene chloride and water may be poured into the processing tank as it is or after chang ed into mixed gas in a preparatory tank. In the embodiment shown in Fig 1, the mixture is fed into the processing tank while kept liquid.

The mixture solution, while kept as it is, is poured into the tank to such extent as immersing the heating -cooling pipes 20 and then stea m having the temperature amounting to 100 and several tens°C is fed from the boiler B to the heating* cooling pipes 20, the mixture solution is heated to 60 130°C, when not only methylene chloride having the boilin g point of 40 OC but also water turns into vapor. The reason why steam and methylene chloride gas are fed at the same time lies in the promotio n of opening of pits with softening of the outer peripheral structure of wood and also promotion of permeation of methylene chloride gas into th e cell of wood. For reducing unavoidable generation of chlorine gas in methylene chloride gas to change color of wood or rot wood, chlorine gas is arrested after passed through the water layer, combined with water, and turned into hydrochloric acid.

o In this invention, as shown in Fig. 6, the mixture solution of meth ylene chloride, water and surfactant reaches no other level than that be low the wood-mounting table 26 even at the highest and wood is not immer sed into the mixture solution. The method of this invention entirely de pends on fumigation in which wood is processed with mixture solution gas absorbed thereinto. A mixture ratio by weight between methylene chlori de solution, water, and surfactant is set at approximately 5 4 1 and the ratio of surfactant is set at 1 or under.

Referring to Fig. 1, the fundamental composition of the method and apparatus of this invention will be described. As an apparatus, the mai n components thereof are the processing tank T and mixture solution tank 14, wherein a mixture solution of methylene chloride, water and surfact ant is thrown into said tank 14. The boiler B, as previously described, serves for gasifying the mixture solution and a compressor C operates t o apply pressure when returning mixture solution in the processing tank T to the mixture solution tnak 14 after completion of processing.

S A vacuum pump P operates for absorbing methylene chloride gas remai ning in the processing tank T and the cell structure of wood W after the mixture solution is forcedly discharged. Methylene chloride gas thus a bsorbed is not allowed to be discharged into atmosphere and, therefore, is liquefied after cooled in the condenser and is returned to the mixtur e solution tank 14 through the condenser pipe 21. A chiller 15 cools co oling water in said condenser 16. A filter 19 is provided for filtering off impurities such as dusts in the mixture solution forced out from th e processing tank T by the compressor C. The cooling water tank 17 is a S. receptacle for cooling water used for liquefaction of mixture solution gas.

Solenoid valves are arranged at various parts. Such solenoid valve s are constructed to be opened and closed by an automatic control device at fixed intervals and automatically operated in steplike order such as <deaeration from wood>, <feed of mixture solution>, <fat removal from w KO) ood>, <cooling of mixture solution>, <return of mixture solution to tank *o <recovery of mixture solution gas>, and <recovery of mixture solution in condenser>.

At the same time, the compressor C, boiler B, vacuum pump P, and ch iller 15 are automatically driven and stopped. Once cycle of this proce o, ss is designed to be completed within 24 hours and wood W, if having bee n subjected to said process, is dried in the drying device at a consider ably higher speed than that required for non-processed wood.

In Fig. 2, a state of the solenoid valve in every step in the wood processing method and apparatus is shown. In the process of (deaeration from wood), the vacuum pump P is driven. A solenoid valve 1 in the cir cuit to connect the vacuum pump P to the condenser 16 as well as another valve 3 adapting the condenser 16 to communicate with the processing ta nk T is also opened. The other solenoid valves are all closed. In this way, the inner space of the processing tank T is made vacuum to a degre e of about 50 Torr, whereby air in the cell of wood W is drawn out.

Then, in the process of <feed of mixture solution>, the solenoid va Ive for adapting the processing tnak T to communicate with the mixture s olution tank 14 is opened whereas the other valves are closed. Thus, th e mixture solution moves to the inner part of the processing tank T so t hat the level of solution in the mixture solution tank may be flush with •that in the processing tank T since both tanks are arranged at the appr oximately same levels.

In the process of <fat removal from wood>, the solenoid valve 7 bet ween the boiler B and the processing tank T and another solenoid valve 9 adapting the processing tank T to communicate with the drain are opened whereas the other valves are closed. Then, steam of high temperature c oming from the boiler B is fed to the heating cooling pipes 20 and the

C

mixture solution in the processing tank T changes into methylene chlori .W de gas, water vapor, and surfactant gas so as to permeate into the cells of wood W. The step of this process of <fat removal from wood> continu es for about 6 hours.

The process of <cooling of mixture solution> will be described. In this case, a solenoid valve 8 adapting the cooling water tank 18 to com \Si"municate with the processing tank T and another valve 10 adapting the pr ocessing tank T to communicate with the cooling tank 17 are opened where as the other valves are closed. Thus, cooling water passes through the inner part of the heating cooling pipes 20 and a temperature in the in ner part of the processing tank T falls below 40°C that is the boiling p oint of methylene chloride, whereby both methylene chloride gas and wate r are returned to liquid.

The process of <return of mixture solution to tank> will be descibe d. In this case, a solenoid valve 2 is opened for escape of air in the processing tank T and another solenoid valves 5 under the processing tan k T as well as further one 6 adapting the compressor C to communicate wi th the processing tank T is opened so as to drive the compressor C. On the other hand, a solenoid valve 12 between the filter 19 and the mixtur e solution tank 14 and another valve 13 adapting the mixture solution ta \O nk 14 with the atmosphere are opened. Then, some degree of pressure act s on the inner part of the processing tank T and liquefied mixture gas i s forcedly returned to the mixture solution tank 14.

The process of <recovery of mixture solution gas in tank> will be d escribed. In this case, the vacuum pump P is driven. A solenoid valve 1 adapting the vacuum pump P to communicate with the condenser 16 and an other valve 3 adapting the condenser 16 to communicate with the processi ng tank T are opened. The other valves are closed. In this state, meth ylene chloride gas present in the processing tank T and having premeated into the cells of wood is recovered by the vacuum pump P. In this case 0 a degree of vacuum is lowered to about 200 Torr.

In the process of <recovery of mixture solution in condenser>, a so lenoid valve 2 communicating with the atmosphere and another valve 11 ad apting the condenser pipe 21 to communicate with the mixture solution ta nk 14 are opened. Hence, recovery of mixture solution such as methylene chloride remaining in the condenser pipe 21 of the condenser 16 can be recovered into the mixture solution tank 14. A series of such processes as above is completed after a lapse of 24 hours.

In Figs. 8 and 9, the structure of a pit of the needle-leaf tree ex emplifying wood W is shown. A dome-like shape is formed fy edges 33 33 of a hole on a part of the cell wall and the center surrounded by said edges 33 33 is made open as a pit 30. A torus 31 acts as a valve to op en and close said pit 30 and is suspended by margo 32 which is a net-lik e membrane composed of net-like cellulose microfibrils.

With the decrease and increase in quantity of water in the cell, sa id torus 31 closes the pit 30 and opens it while departing therefrom, re spectively. Said marge 32 composed of cellulose -microfibrils allows pa ssage of water therethrough and the pit can be opened when the torus 31 is brought into such a state as not closing the pit 30. This invention is intended to dissolve oils and fats present in the cellulose *microfib ril part with methylene chloride, water vapor, and surfactant gas so as to prevent the torus 31 from closing the pit o Referring to Fig. 10, a description will be made on the section of the inner part of the processing tank T in operation of processing. The l heating- cooling pipes 20 are disposed on the inner lower part of the p rocessing tank T and the wood-mounting table 26 is disposed above said h eating cooling pipe 20. Wood is mounted on said wood-mounting table 26 The mixture of water Wa, surfactant solution S, and methylene chlorid e solution Me is poured into the tank to be higher in level than said he 0O ating cooling pipes 20, however, to such extent as not immersing wood W on the wood-mounting table 26 into the solution.

Water Wa and surfactant solution S having specific weight of 1.00 a nd 1.04, respectively, are on the approximately same levels and the latt er S dissolves into the former W to be in one body, thereby composing a layer of <water Wa surfactant solution S> as shown in Fig. 1. In cont rast with this, methylene chloride solution Me having the specific weigh t of 1.33 and incapable of dissolving into water Wa forms a layer beneat h the layer of <water Wa surfactant solution When steam heated to 160°C is fed to the heating coosing pipes 20 disposed in the <water Wa surfactant solution S> layer, the temperature of parts around the hea ting cooling pipes 20 rises. Said heatig cooling pipes 20 are arrange d in the layer of <water Wa surfactant solution S> and the temperature of parts near said layer rises earlier than that of the other parts.

When the temperature of the heating *cooling pipes 20 gradually ris es and reaches about 40 methylene chloride solution Me is heated to reach the boiling point thereof, turns into methylene chloride gas divid ed into bubbles, passes through the layer of <water Wa surfactant solu tion and reaches wood W so as to permeate into pores of said wood W.

In the usual processing of wood and in the case of soft wood W as t he Japanese cedar, the processing operation continues in a state that th S" e mixture solution is heated to about 70°C and methylene chloride gas pa sses through the mixture solution of water and surfactant solution S and 1$ reaches wood W.

In the case of the needle-leaf tree as the pine, above all, such wo od W as exuding resin much, the mixture solution is heated to about and said wood is processed with not only water Wa but surfactant soluti on turned into gas. While said methylene chloride Me passes through wat 010 er Wa and surfactant solution S. C12 <chlorine gas> generated from methy lene chloride is absorbed into water Wa and controlled not to be generat ed further for preventing unfavorable influence thereof from falling on processing. Methylene chloride gas permeates into pores of wood W while attended with surfactant solution S. Hence, removal of fat is sharpene Sd.

In this way, becaruse of a process to prepare a solution containing water Wa, surfactant S, and methylent chloride Me and to heat said solu tion with heating *cooling pipes 20, methylene chloride Me evaporates i nto the processing tank T after passing through water Wa and surfactant solution S, thereby Cl 2 being reduced. Molecules of said methylene chlo ride gas are finer than those of said chloride in the aqueous state and, therefore, easily permeate into fine pores of wood W and oxidize resin thereat.

Methylene chloride entering pores of wood while mixed with surfacta nt solution S sharpens dissolution of resin and production of a large qu antity of methylene chloride gas at a low temperature makes needless a h igh temperature for processing in the tank T.

In this embodiment, a description is made on processing of the natu 0 ral wood, however, a method of and appatatus for processing wood accordi ng to this invention is applicable to repair restoration of carved wood en work such as an old Buddha image carved several tens, several hundred s, or several thousands years ago. In other words, resin remaining in t he inner part of the carved work can be dissolved through such processes S: 15 as putting said old carved work in the processing tank T and applying m ixture solution gas of methylene chloride, water, and surfactant thereto whereby soil and soot on the surface of said work are all washed out.

Washing of the inner part of the cell of the old carved wood as an old Buddha image is enabled by the process as described above. The washing &Oprocess also exhibits sterilizing effect and the carved work can be disp layed in the exhibition room kept at a constant temperature because the surface of the work hardens after elution of resin. In the process of r epair restoration of old works, regardless of the wooden carved work, washing is applicable to even narrow wooden strips digged out from the r emains of an old age and other wooden relics. Washing as above ensures a long term preservation of wooden works.

Wood to be processed according to this invention may be in the form of chip as the material used in the paper making industry and the paper making process can be simplified by removal of oils and fats using a mi xture of methylene chloride solvent solution, water, and surfactant solu tion prepared according to this invention.

(Action of the Invention) The actionof the invention will be described. Referring to Figs. 8 and 9, halogenated hydrocarbon gas used in this invention, particularly methylene chloride gas, steam, and surfactant gas permeate into the pi t part of wood and dissolve cellulose microfibrils composing the margo part 32 of wood so as to make the torus 31 incapable of closing the pit When the pit.30 is opened, resin content in the cell is dissolved 0 by methylene chloride gas and is eluted to the outside. With the bit opened, resin and moisture are easily extracrted by subsequent drying p rocess. Permeation of dyestuff, preservatives, or synthetic resin into the wood cell after extraction of oils and fats is so easy that chemical ly reinformed wood W is obtained. In this processing method in which a 15 mixture is prepared by adding surfactant to methylene chloride solution and water, surfactant gas makes separation and flowing out of eluted res in easy, and malic, citric, succinic, and acetic acids among organic one s generated by chemical reaction of mixture gas as descrived above promo te color development and improve the luster of wood. Addition of surfac o0 tant to the mixture solution denables generation of gas at a low tempera ture and reduces carbonization of wood thanks to a low processing temper ature.

Effects of the Invention This invention composed as above exhibits the following effects.

Since the mixture of methylene chloride gas, surfactant gas, and st eam enables opening of the bit part 30 of wood W, above all, inclusion o f surfactant enables improvement in sharpness in removal and separation of dissolved resin from the pit. Therefore, processing of wood on one h and, in which the structure of wood is adapted to absorb surfactant gas besides pressurized methylene chloride gas and steam, improves resin-dis solving effect three times higher than that of processing on the other h and to immerse wood into methylene chloride solution, whereby speed in d rying of wood is significantly increased and injection of dyestuff, pres ervatives, and synthetic resin into the depth of wood is enabled.

If methylene chloride gas not having passed through the layer of wa ter Wa is directly fed to pores of wood W, the structure of wood W suffe rs an excessive contnet of C12, is damaged to dissolve resin, and requir 10 es a period of about one month for natural drying to remove methylene ch loride gas after processing in the end. Even after natural drying, dama ge to the wood structure is caused and favorable nature of wood is lost.

In the case of direct immersion of wood into methylene chloride soluti on, fat removing power of said solution is too strong and impairs the st 0 ructure of wood.

Accordingly, wood is changed in quality after dried so to be incapa ble of maintaining satisfactory nature as wood. In this invention, sinc e a mixture of water Wa, surfactant solution S, and methylene chloride s S olution Me is prepared and gas of methylene chloride Me is fed to wood a •O fter passed through the layers of both water Wa and surfactant solution S, C12 as a constituent of HCL is absorbed into water and inflicts no da mage to wood because of reduced rate of generation thereof, and methylen e chlorided gas is easily absorbed and recovered by reducing pressure in the processing tank T to be negative and vacuum in the end. Damage to cS the structure of wood W is not caused after recovery of methylene chlori de. Recovery of methylene chloride gas is performed promptly and comple tely and can be re-used with the progress of cooling and liquefaction.

In this way, consumption of methylene chloride solution Me and cost of p rocessing can be reduced.

Mixing of surfactant solution with water and methylene chloride sol ution enables promotion of vaporization of methylene chloride solution a nd water at a low temperature. Water usually vaporizes at the temperatu re of 100 however, can vaporize at a low temperature as a result of addition of surfactant thereto, and, therefore, sufficient pressure can be obtained at a temperature ranging from 40 to 80°C as the highest, whe reby carbonization of wood can be prevented thanks to no need of high pr essure at the high temperature over 80 0

C.

Mixing of surfactant with water and methylene generates organic aci (0 ds as phosphoric, citric, pyruvic, malic, succinic, lactic, formic, acet ic, levulnic, pyloglutamic, propionic, isobutylic, isovaleric acids, and among these acids, phosphoric acid improves development of yellow colo r, citric acid and succinic acid are effective for development of pink c olor whereas acetic acid serves for decoloration for providing whiteness These actions remove reddish color of such wood as generally called red cedar" or "black core" and disliked in the market as low quality one and discolor black core parts so that said wood may be moderate in col or and changed into a high quality one.

Not only a speed for drying wood W processed as above is made highe o 0 r about three times of that required in the conventional manner using me thylene chloride only and water, but also drying of wood, in which decre ase in moisture content lower than a certain balanced rate has so far be en impossible because of closure of the pit 30 even if using hot air, is made possible to provide a further lower moisture content by opening th e pit 30 and breaking the state of balanced moisture content.

In contrast with dyeing of processed wood W which has hitherto been applicable to the surface of wood W only, coloring according to this in vention can be uniformly applied to even the inner part of wood W. Inje ction of preservatives and reinforcing agents of synthetic resin can eas ily be performed.

Since deaeration from wood in the processing tank made vacuum in th e step prior to permeation of methylene chloride gas, steam, and surfact ant gas, permeation of methylene chloride into the inner part of wood W in the vacuum state is enabled and progresses as deeply as enabling open ing of the pit.

The conventional method of processing for repairing and restoring t he remains of wooden work buried in the ground for a long period of age, in which physical processing only is applied to the surface of the work 10 or resin is absorbed only by the surface of the cultural properties, is .o substituted by a new method to elute resin from the internal part of th e work composing wood for enabling chemical washing. In this way, stain s remaining of the surface of the wooden work or having permeated therei nto can be washed out and an appearance of the work approximate to that \5 at the time of manufacturing said work is restored, whereby the surface of work can be hardened after processed and secondary processing is not required.

The use of chips as the meterial of paper making instead of the sol id wood allows removal of oils and fats from the wood cell and chip diss 0 olving process can be simplified.

Claims (12)

1. A method of processing wood depending on fumigation characterized in that mixture of halogenated hydrocarbon solution, water, and surfactant solution is heated and gasified in which gas generated from said mixture solution is adapted to permeate into wood so as to dissolve oils and fats in said wood and provide pores for the membrane of wood cells.

2. A method of processing wood depending on fumigation as set forth in claim 1, wherein a temperature for heating solution is set at 40 0 C or 0 0 a higher.

3. A method of processing wood depending on fumigation as set forth in Claim 1 or 2, wherein wood, halogenated hydrocarbon solution, water, an d surfactant solution are hermetically contained in the pressure vessel, Sheated, and pressurized.

4. A method of processing wood depending on fumigation as set forth in Claim 1 or 2, wherein processed wood is dried. A method of processing wood depending on fumigation as set forth in Claim 1 or 2, wherein wood is colored, after processed, with the use of 10 dyestuff composed of fine particles and is adapted to permeate into sai wood.

006. A method of processing wood depending on fumigation as set forth in S"Claim 1 or 2, wherein solution of preservatives and synthetic resin are injected into the internal part of processed wood.

7. A method of processing wood depending on fumigation charaterized in *.-*that the mixture of methylene chloride solution, water, and surfactant solution is heated to gasify and gas generated from said mixture solutio S, n is adapted to permeate into wood so as to dissolve resin contained in wood and to provide pores for the membrane of wood cells.

8. A method of processing wood depending on fumigation as set forth in Claim 7, wherein a temperature for heating solution is set to be 40°C o r higher.

9. A method of processing wood depending on fumigation as set forth in Claim 7 or 8, wherein wood and the mixture of methylene chloride soluti S on, water and surfactant solution are hermetically contained in the pres sure vessel, heated, and pressurized. A method of processing wood depending on fumigation as set forth in Claim 7 or 8, wherein processed wood is dried.

11. A method of processing wood depending on fumigation as set forth in Claim 7 or 8, wherein dyestuff is adapted to permeate into wood for col oring said wood.

12. A method of processing wood depending on fumigation as set forth in Claim 7 or 8, wherein solutions of preservatives and synthetic resin ar e injected into processed wood.

13. A method of processing wood depending on fumigation as set forth in Claim 7 or 8, wherein a mixture ratio by weight between methylene chlor ide solution, water, and surfactant is set as approximately 5 4 1 an d the ratio of surfactant is set at 1 or under. 10 14. A wood treated by a method of processing wood depending on fumigati on as set forth in Claim 7, wherein said mixture of methylene chloride s olution, water, and surfactant is heated to 60-130 0 C. A method of processing wood depending on fumigation characterized i n that, in an apparatus in which the mixture of methylene chloride solut 15 uion, water, and surfactant solution is prepared, methylene chloride gas steam, and surfactant gas are generated by heating abovesaid mixture s olution, said mixed gas is filled in the processing tank into which wood is hermetically contained so that said gas permeates into wood, and oil content in wood is dissolved to open the pit of the membrane of wood ce cO 11, the inner space of the processing tank is made vacuum for deaerating from wood in the preceding stage of permeating mixture gas into wood.

16. A method of processing wood depending on fumigation as set forth in Claim 1 or 8, wherein wood corresponds to wooden chips as the material for paper making. Dated this twenty-second day of May 1997 EIWA CO., LTD. Patent Attorneys for the Applicant: F.B. RICE CO.