JPH0136401B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a new method and apparatus for treating wood with chemicals. [Prior art and problems to be solved by the invention] In recent years, the demand for wood has increased rapidly, and domestic wood resources alone cannot keep up with the demand, and foreign wood has been imported and used. As is well known. Furthermore, so-called prefabricated construction methods, two-by-four construction methods, and the like have been introduced with the aim of low-cost construction, and with the growth of these construction methods, the demand for plywood mainly made of South Sea wood has increased rapidly. However, these foreign materials have drawbacks such as being susceptible to rotting, rotting, and being eaten by insects, making it even more necessary to preserve them than with conventional wood. Conventionally known wood preservation treatment methods include coating and immersing the wood to be treated in an aqueous solution of a non-volatile chemical such as a chromium compound, copper compound or arsenic compound, or, if necessary, immersing it under reduced or increased pressure. A common method is to impregnate the pores of wood with these chemicals. However, with this method, the treated wood inevitably becomes wood with a high moisture content, and therefore, depending on the application, it cannot be used unless it is later artificially dried, and furthermore, the dimensions of the wood may be distorted due to drying. It is unsuitable for use as a building material or other final product, and there is also the problem that it cannot be painted or otherwise processed unless it dries, and since many of the chemicals used are toxic, there is a risk of dripping or other chemicals from the wood after treatment. There were problems with pollution such as the treatment of waste liquid, and there were also problems such as slow permeability of the chemical solution into the wood, resulting in poor work efficiency. Similar problems have been observed when wood is treated with various non-volatile agents such as dyes or dimensionally stabilizing resins. The inventors of the present invention have conducted intensive research to solve the above-mentioned problems in conventional wood chemical treatments. As a result, we have developed non-volatile agents such as organic preservatives, repellents, insect repellents, dyes, and dimensional stabilizing resins. The above problem can be solved by dissolving the chemical in a volatile organic solvent, impregnating the wood with the chemical in a closed impregnation can under reduced pressure, and recovering and reusing the organic solvent through a heating vaporization-cooling liquefaction process. This finding led to the completion of the present invention. [Means for Solving the Problems] The method for treating wood with chemicals according to the present invention includes the following steps in order to impregnate wood with a wood treatment chemical: (A) charging wood into a closed impregnation can; (B) sealing the impregnating can and reducing the pressure inside the can; (C) introducing a solution of a non-volatile wood treatment agent dissolved in a volatile organic solvent into the impregnating can; (D) draining the remaining solution from the impregnating can; (E) sucking the gas in the impregnating can and heating it to a temperature close to the boiling point of the organic solvent; F) The heated gas is fed into the impregnating can to heat and vaporize the organic solvent in the wood; (G) The organic solvent vapor-containing gas sucked from the impregnating can is heated to vaporize the organic solvent in the wood. liquefying the organic solvent vapor by cooling to a temperature below its boiling point and subjecting the remaining gas to the heating step; (H) recovering the liquefied organic solvent; It is characterized in that it includes the following steps: taking out the impregnated can from the impregnated can. Further, the wood chemical treatment device according to the present invention includes the following elements: (a) a solution tank containing a solution of a non-volatile wood treatment chemical dissolved in a volatile organic solvent; and (b) connected to the solution tank. , a solution inlet and outlet, and a gas inlet and outlet,
and (c) a pressure reduction device connected to the impregnation can, and (d) a gas cooling liquefaction device connected to a gas outlet of the impregnation can. (e) a gas circulation device connected to the gas cooling liquefaction device; (f) a gas heating device disposed between and connected to the gas inlet of the impregnating can and the gas circulation device; It is characterized by having the following. The method and apparatus of the present invention will be described below as a specific example, mainly by means of wood preservation treatment methods and apparatus, but of course the present invention also includes other methods and apparatus for treating wood with non-volatile agents dissolved in volatile organic solvents. It is inclusive. Any non-volatile agent that is soluble in a volatile organic solvent can be used in the wood chemical treatment method of the present invention. For example, wood preservation agents include conventionally used wood preservatives and agents with much lower toxicity. Preferred specific examples of such low toxicity drugs include:
Organotin compounds such as tributyltin oxide (e.g. Teintom, commercially available from Yoshitomi Pharmaceutical); e.g. chlorophenyl iodopropargyl formal (e.g. IF-
Organic iodine compounds such as 1000); Hydroxylamine compounds such as xylazane commercially available from Sankyo Pharmaceutical Co., Ltd.; Benzimidazole compounds such as benzimidazole compounds; Organic copper compounds such as copper naphthenate and copper 8-oxyquinoline; Examples include commercially available organic chlorine compounds such as chlordane; organic phosphorus compounds such as fuoxime commercially available from Takeda Pharmaceutical; and insect repellents such as pyrethroid compounds such as permethrin commercially available from Sumitomo Chemical. The organic solvent used in the wood treatment of the present invention may be any organic solvent as long as it dissolves the organic agent, is a volatile liquid at normal temperature and pressure, and is suitable for recovery by evaporation and condensation. can do. Specific examples of such organic solvents include:
For example, aliphatic hydrocarbons such as n-hexane and n-heptane, aromatic hydrocarbons such as benzene, toluene, and xylene, and alicyclic hydrocarbons such as cyclohexane, such as methylene chloride, chloroform, trichloroethane, Chlorinated hydrocarbons such as trichloroethylene, fluorinated hydrocarbons such as trifluorotrichloroethane, nitrohydrocarbons such as nitromethane, nitroethane, nitriles such as acetonitrile, e.g. propyl alcohol, butyl alcohol, etc. Monohydric alcohols, such as ketones such as acetone, methyl ethyl ketone, methyl propyl ketone, ethers such as isopropyl ether, esters such as methyl formate, ethyl formate, propyl formate, methyl acetate, ethyl acetate, propyl acetate, such as furan. Examples include heterocyclic compounds such as , tetrahydrofuran, and dioxane. In the method of the present invention, since the organic solvent is used in a closed system, there is almost no problem in using a low-boiling flammable solvent, but preferred organic solvents include halogenated aliphatic and aromatic carbonized It is hydrogen. Hereinafter, an example of the structure of the wood chemical treatment method and apparatus of the present invention and its operating method will be described with reference to the attached FIG. 1. The wood chemical treatment apparatus of the present invention includes a closed impregnating can 1 having a space containing wood 2 to be treated.
The impregnating can 1 is made of stainless steel or has a wetted part made of stainless steel, and has an appropriate size depending on the size of the wood to be treated. Moreover, it is also possible to charge a plurality of pieces of wood 2 or a large number of pieces of wood 2 inside and process it. The lid 3 of the impregnating can 1 is opened and the wood 2 to be treated is charged inside. Next, after closing the lid 3 and sealing the impregnating can 1, the gas inlet valve 4, the gas outlet valve 5, and the valve 6 are closed, and the chemical liquid injection/discharge port valve 7 and valve 8 are opened. The pressure reducing device, that is, the vacuum pump 9 is driven to reduce the pressure inside the impregnating can 1. The degree of reduced pressure inside the impregnating can 1 varies depending on the tree species and shape, but is usually 60 mmHg (degree of vacuum).
It is preferable to do the following. After the inside of the impregnating can 1 reaches a predetermined degree of vacuum, it is held in that state for a while to remove the gas inside the main material 2, and then the valve 8 is closed and the valve 6 is opened to adjust the amount in the chemical solution tank 10 in advance. The stored chemical solution is introduced into the can via the chemical solution inlet/outlet valve 7. After introducing the required amount of the chemical into the can, the valve 7 is closed and the wood is left as it is for an appropriate period of time to allow the chemical to permeate into the wood 2. The leaving time varies depending on the tree species and shape, but approximately 30 minutes is usually sufficient. After the impregnation is completed, the vent valve 17 is opened to return the inside of the can to atmospheric pressure, the valve 6, and the chemical injection/discharge port valve 7 are opened to return the excess chemical to the chemical tank 10. Next, vent valve 17, valve 6, and valve 7 are closed. Next, the gas inlet valve 4, the gas outlet valve 5, and the valve 11 are opened, and the gas circulation device, that is, the blower 1 is turned on.
4 to suck the gas (including organic solvent vapor) inside the impregnating can 1. Next, this sucked gas is
The organic solvent vapor in the gas is condensed and liquefied by cooling with a gas cooling liquefaction device, that is, a cooler 13,
The liquefied organic solvent is passed through a valve 11 to a recovery tank 15.
to be collected. The remaining gas is sent to a gas heating device or heater 12 by a blower 14,
Here, depending on the type of organic solvent, heating is performed at the outlet of the heater 12 to a temperature necessary to evaporate the organic solvent, for example, 30°C to 100°C. The heated gas is introduced into the impregnating can 1 through the gas inlet valve 4, heating the wood in the can and evaporating the organic solvent from the wood. At this time, the temperature of the heated gas does not necessarily have to be higher than the boiling point of the organic solvent because the pressure inside the impregnating can is reduced, so that the organic solvent can be gradually vaporized. The gas containing the organic solvent vapor in the can generated in this manner is transferred from the impregnating can 1 to the cooler 13 to
The organic solvent vapor in the sucked gas is cooled and liquefied by the cooler 13 during the circulation in the order of the blower 14 → heater 12 → impregnation can 1, and is recovered in the recovery tank 15. If the recovered organic solvent is sent to the chemical tank 10 by opening the transfer valve 16,
It can then be reused for preparing drug solutions. As explained above, according to the present invention, since an organic solvent is used as a medium instead of water as in conventional methods, the wood to be treated does not become a high moisture content material, and therefore the treated wood does not become a high moisture content material. In addition to not requiring subsequent drying, in the course of the treatment method of the present invention,
It has the advantage that the moisture content of the wood is rather reduced, that is, the wood is dried at the same time. In addition, since the treatment method of the present invention uses an organic solvent, the chemical is more effectively impregnated into the wood compared to the conventional method using an aqueous treatment liquid, and the effect of chemical treatment on wood is also high. Moreover, compared to conventional aqueous solutions of inorganic chemicals, the low-toxicity chemicals can be used in a closed system, so there is no chance of the chemicals dripping from the wood after treatment or the generation of waste fluid, reducing pollution. It is also advantageous from the viewpoint of prevention. Further, in the treatment method of the present invention, the treated wood can be coated with paint or varnish immediately after treatment, and the organic solvent can be recovered and recycled for reuse, which is advantageous in terms of cost. The present invention will be further explained below with reference to Examples.
It goes without saying that the scope of the present invention is not limited to these Examples. In the following examples, "%" is expressed as "% by weight" unless otherwise specified. Example 1 Lauan material 5 with a moisture content of 20% and 5 cm square and 100 cm long
The book was placed in the impregnation can 1 of the apparatus shown in FIG. 1, and the lid 3 was closed and sealed. Close valves 4, 5, 6,
Open the valves 7 and 8 and operate the vacuum pump 9 to reduce the pressure inside the can to 60mmHg, and remove the air inside the can and the wood by 30mmHg.
It was evacuated for a minute. Next, the valve 8 is closed, the valve 6 is opened, and the chemical liquid prepared and stored in the chemical liquid tank 10, that is, methylene chloride (boiling point:
A chemical solution containing 1.0% IF-1000 and 0.5% chlordane dissolved at 40.1℃) is introduced into the can. After the inside of the can is filled with the chemical solution, valve 7 is closed and left for about 30 minutes to dissolve into the wood. Permeated with chemical solution. The amount of drug solution injected at this time is
It was 150Kg/ ^m3 . Next, open the valve 17 to return the inside of the can to the atmosphere, open the valves 6 and 7, and drain the excess chemical into the chemical tank 10.
Sent it back to. Next, valve 7 is closed, and valves 4, 5, 11
was opened, valve 17 was closed, heater 12 was set and operated so that the gas temperature at its outlet was 40°C, and both cooler 13 and blower 14 were operated. The gas sent from the blower 14 was continuously circulated through a closed circuit of the heater 12, the impregnating can 1, and the cooler 13, and the methylene chloride in the wood was collected into the recovery tank 15, and the treatment was completed after 5 hours. The methylene chloride recovery rate at this time was 84.5%, and the moisture content of the wood after treatment was 18%. A test piece was taken from this treated wood and JIS A
According to 9302 "Testing method for preservative efficacy of wood preservatives",
The preservative effect was confirmed. That is, the test bacteria were two types of wood-decaying fungi, Ophthalmia nigra and C. versicolor, cultured in a sea sand culture medium, and a test piece that had been weathered 0 times and 10 times was placed on top of the test bacteria, and the temperature was 26±.
Leave to decay for 90 days at 2℃ and relative humidity of 70% or higher. After decay, take out the specimen, remove mycelium and other deposits from the surface, dry it, measure its weight, and calculate the weight loss rate. Efficacy values were determined by comparison with untreated test specimens. Similarly, a test piece was taken from this treated wood, and the insect repellent efficacy was confirmed in accordance with Japan Wood Preservation Association Standard No. 8 "Testing Method for Insect Repellent Efficacy of Wood Insect Repellents (1)". That is, 5 test specimens each consisting of 5 larvae, that is, 30 specimens, were placed into holes made in both ends of the test piece with artificially reared larvae of the Japanese yellow beetle, and the larvae were incubated at approximately 25°C and 70% to 75% RH. After rearing for 21 days,
Observation was made using a soft X-ray device, and efficacy was determined based on the average mortality rate. In addition, as a comparative example of antiseptic and insect repellent effects, the same waran wood was treated with "chromium, copper, and arsenic compound wood preservatives" 2.0 specified in JIS K 1554.
A similar test was conducted on specimens treated with the % aqueous solution. The results of the above tests are shown in Tables 1 and 2 below. Example 2 2 cm (thickness) x 30 cm (width) x 100 cm with moisture content of 18%
(long) using acetone (boiling point 56.1)
The same procedure as in Example 1 was carried out using a working solution in which 1.0% IF-1000 and 0.1% fuoxime were dissolved in 1.0% IF-1000 and 0.1% fuxime. However, the temperature of the heater was set at 50°C. The injection amount at this time was 132 Kg/m ³ , the recovery rate was 87.3%, and the water content after treatment was 16%. Test specimens were collected from this treated wood in the same manner as in Example 1, and the antiseptic efficacy and insect repellent efficacy were determined. The results are shown in Tables 1 and 2 below. Example 3 2cm (thickness) x 5cm (width) x 100cm with moisture content of 25%
Using 10 pieces of (long) hemlock wood, 1.0% Taintom was added to 1,1,1-trichloroethane (boiling point 75℃).
The same operation as in Example 1 was carried out using a working solution in which 0.5% permethrin was dissolved. However, the temperature of the heater was set at 70°C. The injection amount at this time was 187 kg/m ³ , the recovery rate was 83.6%, and the water content after treatment was 17%. Test specimens were collected from this treated wood in the same manner as in Example 1, and tested for antiseptic efficacy and insect repellent efficacy. The results are shown in Tables 1 and 2 below.

[Table] The above passes.

[Table] [Effects of the Invention] The method and apparatus of the present invention can inject and fix a treatment chemical into wood without increasing its moisture content, and can improve the yield of the organic solvent used in the chemical. It can be collected with.

[Brief explanation of drawings]

FIG. 1 is a drawing showing an example of a wood chemical treatment apparatus according to the present invention. 1... Impregnated can, 2... Wood to be treated, 3... Lid,
10... Chemical tank, 12... Heater, 13...
...Cooler, 14...Blower, 15...Recovery tank.

Claims (1)

[Claims] 1. In order to impregnate wood with a wood treatment agent, (A) the wood is placed in a closed impregnation can; (B) the impregnation can is sealed and the pressure inside the can is reduced; (C) introducing a solution of a non-volatile wood treatment agent dissolved in a volatile organic solvent into the impregnating can to impregnate the wood, and (D) discharging the remaining wood from the impregnating can. (E) sucking the gas in the impregnating can and heating it to a temperature close to the boiling point of the organic solvent; (F) feeding the heated gas into the impregnating can; (G) cooling the organic solvent vapor-containing gas sucked from the impregnation can to a temperature lower than the boiling point of the organic solvent to liquefy the organic solvent vapor; and subjecting the remaining gas to the heating step, (H) recovering the liquefied organic solvent, and (I) taking out the treated wood from the impregnation can. 2 (a) a solution tank containing a solution of a non-volatile wood treatment chemical dissolved in a volatile organic solvent; (b) connected to the solution tank and having a solution inlet, an outlet, and a gas inlet and outlet; and
and (c) a pressure reduction device connected to the impregnation can, and (d) a gas cooling liquefaction device connected to a gas outlet of the impregnation can. (e) a gas circulation device connected to the gas cooling liquefaction device; (f) a gas heating device disposed between and connected to the gas inlet of the impregnating can and the gas circulation device; A chemical treatment device for wood.