Preservation treatment method for water-soaked excavated wood

Abstract

To provide a preservation treatment method and preservation treatment device of waterlogged wood, which require a short time for immersion into waterlogged wood, do not cause deterioration of preservation state due to storage environment, and are not high in requirement for facilities and the like such as in the case where organic solvents are used.SOLUTION: A preservation treatment device includes: an impregnation container 100, which serves as a semi-closed treatment tank where preservation agent 900 is stored and water-soaked construction timber WD is set; a circulation mechanism 200 that circulates the aforementioned preservation treatment agent 900 and drips it from above the water-immersed construction wood WD; and humidification / dehumidification mechanism 300 for humidifying and dehumidifying inside the impregnation container 100. The preservation treatment agent is a mixture of saturated primary alcohol with 16 carbon atoms and saturated primary alcohol with 18 carbon atoms in a weight ratio of 3:2, and added with a cationic surfactant.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a preservation method for water-soaked excavated wood, such as wooden coffins, wooden tablets, and wooden products excavated from various ancient tombs and ruins, that enables long-term preservation of water-soaked excavated wood while maintaining its appearance and shape. [Background technology]

[0002] In Japan, where a "wood culture" has been cultivated since ancient times, a huge amount of wooden artifacts have been excavated throughout the country. Excavated wood, including wooden artifacts such as wooden tablets, wooden coffins, wooden daily necessities, and wooden structures, is a cultural heritage of humanity and is important to modern people as a resource that teaches us about the activities of people in the past. On the other hand, much of the excavated wood is fragile and contains a large amount of moisture, which causes it to shrink significantly when dried, making it essential to carry out preservation treatments to stabilize it. However, because preservation treatment of excavated wood takes a long time, much of it has to be stored underwater, which has led to serious problems across the country, such as a lack of storage space and the deterioration of the wood due to long-term storage. Given this background, improving the efficiency of preservation treatment for excavated wood that contains water, i.e., water-soaked excavated wood, has been positioned as one of the most important research topics in cultural property preservation science.

[0003] Conventionally, stabilization has been attempted by impregnating water-soaked excavated wood with a solution containing a solute that is solid at room temperature, and then solidifying it by drying or cooling. Various materials have been proposed as impregnating agents for water-soaked excavated wood, along with their application methods.

[0004] One of the methods developed in Northern Europe is the polyethylene glycol (PEG) impregnation method. PEG is still used worldwide today due to its advantages of being highly safe for the human body, water-soluble, and easy to use. For example, there is a technique described in Japanese Patent Application Laid-Open No. 02-02004. In addition, preservation treatment methods have been developed that involve impregnating wood with natural resins, fatty acid esters, and higher alcohols, which have smaller molecular weights than PEG and are insoluble in water. For example, the techniques described in Japanese Patent Laid-Open No. 2011-026259 and Japanese Patent Laid-Open No. 04-056401 are known.

[0005] [Patent Document 1] Japanese Patent Application Publication No. 02-02004 [Patent Document 2] Japanese Patent Application Laid-Open No. 2011-026259 [Patent Document 3] Japanese Patent Publication No. 04-056401 DISCLOSURE OF THE INVENTION [Problem to be solved by the invention]

[0006] However, when chemicals penetrate water-leached wood, if the difference in concentration between the inside of the wood and the surrounding chemical solution becomes too great, the wood may lose moisture due to osmotic pressure, causing it to shrink. Therefore, regardless of the type of chemical, the above-mentioned technology first immerses the water-leached wood in a low-concentration chemical solution, and then gradually works to penetrate the inside of the water-leached wood by utilizing the slow diffusion phenomenon caused by the concentration gradient of the solute chemical, which in principle takes a long time. Furthermore, PEG is a polymeric material that takes a considerable amount of time to penetrate into the wood, and wood excavated after preservation treatment is hygroscopic, so depending on the humidity and temperature of the storage environment, PEG may dissolve, worsening the wood's condition.

[0007] Furthermore, in the method using fatty acid esters or higher alcohols, a dehydration step is required in advance to replace the moisture in the water-leached wood with an organic solvent such as methanol or tertiary butyl alcohol. This dehydration process, like the penetration of chemicals such as PEG mentioned above, takes a long time because it is carried out by first immersing the wood in a low-concentration aqueous solution of an organic solvent and then gradually increasing the concentration of the organic solvent. After the dehydration process, the water-leached excavated wood must be immersed in a solution containing an organic solvent as the solvent and a water-insoluble material as the solute, and the solute concentration must be gradually increased to allow penetration, which requires a great deal of time and effort.

[0008] For example, the method of using higher alcohol on water-soaked zelkova wood, which is approximately 30 mm in length, width, and height (approximately 30 mm square), takes approximately 20 weeks, or 5 months, as shown below. Dehydration process (replacement with organic solvent (methanol, etc.)) Immersion in 50% methanol solution (2 weeks) Immersion in 70% methanol solution (2 weeks) Immersion in 90% methanol solution (2 weeks) Immersed in 100% methanol (2 weeks) Immersion in 100% methanol (2nd time, 2 weeks) Higher alcohol impregnation process Immersed in 20% higher alcohol (methanol solution) (2 weeks) Immersed in 40% higher alcohol (methanol solution) (2 weeks) Immersed in 60% higher alcohol (methanol solution) (2 weeks) Immersed in 80% higher alcohol (methanol solution) (2 weeks) Drying process (removal of residual methanol) Natural drying (air drying, 2 weeks)

[0009] Furthermore, when organic solvents are used, care must be taken in handling them and in ventilating the area where they are used, so in reality they cannot be used anywhere, anytime.

[0010] The present invention was devised in light of the above circumstances, and aims to provide a method and equipment for preserving water-soaked excavated wood that allows penetration into the wood in a short period of time, does not lead to deterioration of the preservation condition due to the storage environment, and does not require high equipment requirements as when organic solvents are used. [Means for solving the problem]

[0011] The preservation treatment method for water-soaked excavated wood according to the present invention involves immersing the water-soaked excavated wood, with a portion exposed, in a preservative treatment agent made from a higher alcohol to which a cationic surfactant has been added, allowing the preservative treatment agent to penetrate the water-soaked excavated wood while evaporating the water in the wood, and then cooling the wood to solidify the preservative treatment agent.

[0012] Another method for preserving water-soaked excavated wood according to the present invention involves immersing the wood, with a portion exposed, in a preservative treatment agent made from higher alcohol to which a cationic surfactant has been added. While evaporating the water in the wood, the preservative treatment agent is dripped onto the exposed portion of the wood to allow it to penetrate the wood, and then cooling the wood to solidify the preservative treatment agent.

[0013] Furthermore, a further method for preserving water-soaked excavated wood according to the present invention involves dripping a preservative consisting of a higher alcohol to which a cationic surfactant has been added from above the water-soaked excavated wood, and the water-soaked excavated wood is held above the liquid level of the preservative.

[0014] In the preservation treatment method for water-soaked excavated wood, it is preferable to place the water-soaked excavated wood so that its fibers are not horizontal.

[0015] In addition, in the preservation treatment method for water-soaked excavated wood, the preservation treatment chemicals and water-soaked excavated wood are placed in a semi-sealed treatment tank, and air with a low vapor pressure is blown into the semi-sealed treatment tank from within the semi-sealed treatment tank, humidifying and dehumidifying the inside of the semi-sealed treatment tank.

[0016] Another method for preserving water-soaked excavated wood according to the present invention involves immersing the wood in a preservative treatment agent made from higher alcohol to which a cationic surfactant has been added, and then cooling the preservative treatment agent to solidify it.

[0017] In this case, the excavated wood may be immersed in a preservative treatment agent made of higher alcohol to which a cationic surfactant has been added, and the preservative treatment agent may be heated to a temperature above its melting point and below its flash point, and then cooled to solidify the preservative treatment agent.

[0018] In another method for preserving water-soaked excavated wood, the wood is immersed in the preservative treatment chemicals so that the fibers are not horizontal.

[0019] The preservation treatment device for water-soaked excavated wood of the present invention comprises a semi-closed treatment tank in which preservative treatment agents are stored and in which the water-soaked excavated wood is placed, a circulation mechanism that circulates the preservative treatment agent and drips it from above the water-soaked excavated wood, and a humidification / dehumidification mechanism that humidifies and dehumidifies the inside of the semi-closed treatment tank, and the preservative treatment agent is a higher alcohol to which a cationic surfactant has been added. The higher alcohol is preferably a saturated primary alcohol having 16 or 18 carbon atoms, and more preferably a mixture of a saturated primary alcohol having 16 carbon atoms and a saturated primary alcohol having 18 carbon atoms in a weight ratio of 3:2.

[0020] The cationic surfactant added to the preservative treatment agent used in the water-leached excavated wood preservation treatment device is preferably either cetyltrimethylammonium chloride or stearyltrimethylammonium chloride. [Effects of the Invention]

[0021] The preservation treatment method for water-soaked excavated wood according to the present invention involves immersing the water-soaked excavated wood in a partially exposed state in a preservative treatment agent made from a higher alcohol to which a cationic surfactant has been added, or dripping a preservative treatment agent made from a higher alcohol to which a cationic surfactant has been added from above the water-soaked excavated wood. This evaporates the water in the water-soaked wood and allows the higher alcohol to penetrate directly without dilution, thereby dehydrating the water inside the water-soaked excavated wood and replacing it with the higher alcohol, thereby allowing the penetration into the water-soaked excavated wood to be completed in an extremely short time and preventing deterioration of the preservation condition due to the storage environment. Furthermore, since there is no need to use organic solvents as in the past, there is also the advantage that the requirements for equipment etc. are not high.

[0022] The preservation treatment device for water-leached excavated wood of the present invention comprises a semi-sealed treatment tank in which the preservation treatment agent is stored and the water-leached excavated wood is placed; a circulation mechanism that circulates the preservation treatment agent and drips it from above the water-leached excavated wood; and a humidification / dehumidification mechanism that humidifies and dehumidifies the inside of the semi-sealed treatment tank.The preservation treatment agent is a heated and melted higher alcohol to which a cationic surfactant has been added.As a result, the preservation treatment agent penetrates the water-leached excavated wood in a short period of time, and the preservation condition does not deteriorate due to the storage environment.This makes it possible to provide a preservation treatment device for water-leached excavated wood that does not require as much equipment as when using organic solvents. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is a schematic diagram of a preservation treatment device for water-soaked excavated wood according to an embodiment of the present invention; [Figure 2] FIG. 1 is an explanatory diagram illustrating the principle by which higher alcohols in a preservative treatment agent for water-leached excavated wood according to an embodiment of the present invention are replaced with moisture in the water-leached excavated wood. [Figure 3] 1 is a schematic perspective view of a test specimen used to demonstrate the effectiveness of a preservation treatment method for water-soaked excavated wood according to an embodiment of the present invention. FIG. [Figure 4] 10 is a schematic diagram showing the effect of a preservation treatment method for water-soaked excavated wood according to another embodiment of the present invention. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0024] In a preservation treatment method according to an embodiment of the present invention, water-leached excavated wood WD is immersed in a preservation treatment agent 900, which is made of higher alcohol to which a cationic surfactant has been added, with a portion of the wood exposed. The water in the water-leached excavated wood WD is evaporated while the preservation treatment agent 900 penetrates the water-leached excavated wood WD, and the wood is then cooled to solidify the preservation treatment agent 900.

[0025] First, the preservative treatment agent 900 used in this method for preserving excavated wood leached in water is a mixture of heated and melted higher alcohol and a cationic surfactant added thereto. More specifically, the higher alcohol used has a carbon number of at least 16. Preferably, the higher alcohol is a mixture of a carbon number of 16 and a carbon number of 18 in a weight ratio of 3:2. In this specification, higher alcohols with different carbon numbers, such as cetyl alcohol (C 16 H 33 OH) and stearyl alcohol (C 18 H 37 OH) in a weight ratio of 3:2. MIX It is written as OH(3:2).

[0026] As the cationic surfactant, for example, a quaternary ammonium salt type cetyltrimethylammonium chloride (CTAC) or stearyltrimethylammonium chloride (STAC) is used.

[0027] Both CTAC and STAC have a trimethylammonium type hydrophilic group, and CTAC has a 16-carbon linear alkyl group as a hydrophobic group, while STAC has an 18-carbon linear alkyl group. These alkyl groups are the same as cetyl alcohol (C 16 H 33 OH), stearyl alcohol with 18 carbon atoms (C 18 H 37 It is thought to have a high affinity because it has the same structure as that of hydroxylase (OH).

[0028] The water-leached excavated wood preservation treatment device 1000 used in the method for preserving water-leached excavated wood using the preservative treatment chemicals 900 described above comprises an impregnation container 100 as a semi-sealed treatment tank in which the preservative treatment chemicals 900 are stored and the water-leached excavated wood WD is placed, a circulation mechanism 200 that circulates the preservative treatment chemicals 900 and drips them onto the water-leached excavated wood WD from above, and a humidification / dehumidification mechanism 300 that humidifies and dehumidifies the inside of the impregnation container 100.

[0029] An impregnation vessel 100 is used as the semi-closed treatment vessel. This impregnation vessel 100 is set in a thermostatic bath 400. This thermostatic bath 400 incorporates the impregnation vessel 100 as a semi-closed treatment vessel in which a preservative treatment agent 900 is stored, a humidifier 310 for humidifying the impregnation vessel 100, and a liquid feed pump 210 that constitutes a circulation mechanism 200 for circulating the preservative treatment agent 900 stored in the impregnation vessel 100.

[0030] The impregnation vessel 100 is fitted with a holding member 110 for holding the water-leached excavated wood WD above the liquid level of the preservative treatment chemicals 900. The water-leached excavated wood WD is placed on the holding member 110, and the preservative treatment chemicals 900 are dripped onto the water-leached excavated wood WD from above. The holding member 110 is a mesh base so that the preservative 900 dripped from above drips downward. Furthermore, a temperature and humidity sensor 360 for measuring the temperature and humidity inside the impregnation vessel 100 is set in the impregnation vessel 100 .

[0031] The liquid supply pump 210 is connected to a suction pipe 220 that sucks up the preservative treatment agent 900 stored in the impregnation container 100, and a drip pipe 230 that drips the sucked up preservative treatment agent 900 from above the water-soaked excavated wood WD. The drip pipe 230 is set at a position where the preservative treatment chemicals 900 can be dripped from directly above the water-soaked excavated wood WD.

[0032] Furthermore, the impregnation vessel 100 is connected to a dehumidification exhaust pipe 321 for sending the air inside the impregnation vessel 100 to a dehumidifier 320 set outside the thermostatic bath 400 . Further, the dehumidifier 320 is connected to a dehumidification air supply pipe 322 which is connected to an air pump 330 for sending the air dehumidified by the dehumidifier 320 to the impregnation vessel 100 . The dehumidifier 320 constitutes a part of a humidification / dehumidification mechanism 300 that humidifies and dehumidifies the inside of the impregnation container 100 .

[0033] Meanwhile, the humidifier 310 is a container that stores water WA for humidification, and constitutes part of a humidification / dehumidification mechanism 300 that humidifies and dehumidifies the inside of the impregnation container 100. Connected to the humidifier 310 are a primary humidification pipe 311 whose tip is immersed in the water WA, and a secondary humidification pipe 312 whose tip is not immersed in the water WA.

[0034] In addition to the humidifier 310 and dehumidifier 320 described above, the humidification / dehumidification mechanism 300 also includes an air pump 330 that sends humidified air to the humidification primary pipe 311 and dry air to the dehumidification air supply pipe 322, an electromagnetic valve 340 that is located downstream of the air pump 330 and switches between the humidification primary pipe 311 and the dehumidification air supply pipe 322, and a control unit 350 that is connected to the temperature and humidity sensor 360 and controls the air pump 330 and the electromagnetic valve 340 in accordance with the temperature and humidity inside the impregnation container 100.

[0035] The suction pipe 220, drip pipe 230, dehumidification exhaust pipe 321, dehumidification air supply pipe 322, humidification secondary pipe 312, and temperature / humidity sensor 360 are positioned inside the impregnation vessel 100 by penetrating the lid 120 of the impregnation vessel 100.

[0036] The water-soaked excavated wood preservation treatment device 1000 configured as described above treats the water-soaked excavated wood WD as follows.

[0037] In the following description, the initial humidification target value is the relative humidity that the humidity inside the impregnation vessel 100 should reach at the start of treatment, the upper humidity limit is the upper limit allowed for the relative humidity inside the impregnation vessel 100, and the lower humidity limit is the lower limit allowed for the relative humidity inside the impregnation vessel 100.

[0038] First, the preservative 900 is stored in the impregnation container 100, and the holding member 110 is set so that the upper surface is not immersed in the preservative 900. The water-soaked excavated wood WD is placed on the holding member 110. The drip pipe 230 of the circulation mechanism 200 is positioned directly above the water-soaked excavated wood WD, and the tip of the suction pipe 220 of the circulation mechanism 200 is immersed in the preservative 900. The temperature of the thermostatic bath is maintained at a preset temperature (above the melting point of the higher alcohol solution to which the cationic surfactant has been added, for example, 75° C.).

[0039] At the start, the air pump 330 is turned on, and the electromagnetic valve 340 turns on the primary humidification pipe 311 . This sends air to the humidifier 310, and water vapor is sent from the humidifier 310 to the impregnation vessel 100 via the secondary humidification pipe 312. The internal humidity of the impregnation vessel 100 is increased until it reaches the initial humidification target value. This is to prevent the water-soaked earthenware wood WD from drying out in the initial stage. At the same time, the liquid pump 210 is turned on, and the preservative treatment agent 900 is dripped continuously or intermittently from above the water-soaked excavated wood WD.

[0040] When the internal humidity of the impregnation vessel 100 reaches the initial humidification target value, the air pump 330 is turned off. At the same time as the air pump 330 is turned off, the electromagnetic valve 340 closes the humidification primary side pipe 311 and opens the dehumidification air supply pipe 322 side.

[0041] The humidity inside the impregnation vessel 100 increases over time. When the humidity inside the impregnation vessel 100 reaches a predetermined upper humidity limit, the air pump 330 is turned on to send the water vapor inside the impregnation vessel 100 to the dehumidifier 320 via the dehumidification-side exhaust pipe 321. When the internal humidity of the impregnation vessel 100 reaches a predetermined lower humidity limit, the air pump 330 is turned off to promote the generation of water vapor from the water-soaked excavated wood WD.

[0042] When the internal humidity of the impregnation vessel 100 reaches the upper humidity limit due to the generation of water vapor from the water-soaked excavated wood WD, the air pump 330 is turned on again to send the water vapor inside the impregnation vessel 100 to the dehumidifier 320 via the dehumidification-side exhaust pipe 321. When the internal humidity of the impregnation vessel 100 reaches the predetermined lower humidity limit again, the air pump 330 is turned off.

[0043] While repeating this process, if the internal humidity of the impregnation container 100 does not reach the upper humidity limit after a predetermined period of time has elapsed, the upper and lower humidity limits of the internal humidity of the impregnation container 100 are lowered by a certain value and the same process is carried out to promote the generation of water vapor from the water-soaked excavated wood WD again.

[0044] If, by continuing this process, the internal humidity inside the impregnation container 100 does not rise over time to the upper humidity limit at that time (for example, the relative humidity remains stable at approximately 30%) even when the air pump 330 is turned off, this means that the moisture inside the water-soaked excavated wood WD has been sufficiently dehydrated and the higher alcohol has been impregnated into it. Furthermore, the preservative 900 containing higher alcohol is constantly dripped from above the water-leached excavated wood WD, so the preservative 900 is supplied from above the water-leached excavated wood WD, and the moisture inside the water-leached excavated wood WD is released downward, resulting in high efficiency of impregnation with the preservative 900. That is, the water-leached excavated wood preservation treatment device 1000 makes it possible to simultaneously dehydrate the water-leached excavated wood WD and impregnate it with a higher alcohol.

[0045] The following factors are thought to be the reasons why the moisture inside the water-leached excavated wood WD is dehydrated in this way and replaced with the higher alcohol in the preservative treatment agent 900. First, the surface of the cell walls (containing cellulose) of the water-leached excavated wood WD becomes coated with the hydrophobic groups of the cationic surfactant contained in the preservative treatment agent 900, and becomes wet with the preservative treatment agent 900.

[0046] This takes advantage of the fact that the cell walls (including cellulose) in water-leached wood WD become negatively charged in water, making them more likely to bond with cationic substances, as shown in Figure 2. Specifically, cationic surfactants contain positively charged hydrophilic groups (cationic portions) and hydrophobic groups (alkyl groups). The hydrophilic groups (cationic portions) adsorb to the negatively charged cell walls (including cellulose), and the hydrophobic groups enhance their affinity for water-insoluble chemicals, such as higher alcohols. This results in the surface of the cell walls (including cellulose) of water-leached wood WD being covered with hydrophobic groups in combination with the hydrophilic groups, creating a hydrophobic state. This improves the wettability of water-leached wood WD with higher alcohols.

[0047] Furthermore, the water inside the water-soaked excavated wood WD slowly evaporates, creating a negative pressure inside the water-soaked excavated wood WD, and the preservative 900 is absorbed into the wood from the parts that are wet with the preservative 900. In this way, if the wood is left partially exposed from the preservative treatment agent 900, it is thought that by controlling the ambient temperature and the rate of water evaporation, the hydrophobicization of the cell walls (cellulose) of the water-leached excavated wood WD and the active impregnation of the higher alcohols in the preservative treatment agent 900 will proceed simultaneously.

[0048] When the water-leached wood preservation treatment device 1000 described above was used to treat a test specimen TP made of Zelkova wood with dimensions of approximately 30 mm (approximately 30 mm square) as shown in Figure 3, the dimensions of each part were as follows: This test specimen TP was actually treated from water-leached wood WD excavated from an archaeological site. The vertices of the test piece TP were designated as ABCDEFGH, and the dimensions between the vertices were measured. The dimension α between the vertices before treatment, the dimension β between the vertices after impregnation with the preservative treatment agent 900, and the dimension γ between the vertices after impregnation and solidification were measured.

[0049] This specimen TP was installed so that its fibers were not horizontal. Therefore, the preservative 900 dripped from above the water-soaked excavated wood WD flows from top to bottom along the fibers. This flow of the preservative 900 is smooth because it is not against gravity. Note that "the fibers should not be horizontal" means that the angle θ between the fibers and the horizontal is 0°<θ≦90°, and in order to effectively utilize the effect of gravity, it is desirable that θ be as close to 90° as possible.

[0050] Table 1 shows the results of the preservative treatment using a zelkova wood specimen of approximately 30 mm square as the test specimen TP, and the preservative treatment 900 was a higher alcohol containing cetyl alcohol (C 16 H 33 OH) and stearyl alcohol with 18 carbon atoms (C 18 H 37 OH) in a weight ratio of 3:2 (C MIX OH (3:2)) was used, and the test specimen TP was positioned above the liquid level of the preservative 900.

[0051] Table 2 shows the results of the preservative treatment with a 30mm square Zelkova wood specimen (TP) and a 16 carbon atom cetyl alcohol (C 16 H 33 OH) and stearyl alcohol with 18 carbon atoms (C 18 H 37 OH) in a weight ratio of 3:2 (C MIX OH (3:2) with 5% STAC added as a cationic surfactant, and the test specimen TP was placed above the liquid surface of the preservative 900.

[0052] Table 3 shows the results of the preservative treatment with a zelkova wood specimen of approximately 30 mm square as the test specimen TP, and the preservative treatment with a higher alcohol, cetyl alcohol (C 16 H 33 OH) with 5% STAC added as a cationic surfactant, and the test specimen TP was placed above the liquid level of the preservative 900.

[0053] Table 4 shows the results of the preservative treatment with a 30mm square Zelkova wood specimen as the test specimen TP, and the preservative treatment with a higher alcohol, cetyl alcohol (C 16 H 33 OH) and stearyl alcohol with 18 carbon atoms (C 18 H 37 OH) in a weight ratio of 3:2 (C MIX OH (3:2) with 5% STAC added as a cationic surfactant, and the lower part of the test specimen TP was always immersed in the preservative treatment agent 900, while the upper part was exposed from the preservative treatment agent 900.

[0054] Table 5 shows the results of using a zelkova wood specimen approximately 30 mm square as the test specimen TP and drying the specimen TP in a constant temperature dryer at 105°C or higher for more than 6 hours.

[0055] [Table 1]

[0056] [Table 2]

[0057] [Table 3]

[0058] [Table 4]

[0059] [Table 5]

[0060] The processing results shown in Tables 1 to 5 reveal the following. As shown in Table 2, the preservative 900 is a higher alcohol containing 16 carbon atoms, cetyl alcohol (C 16 H33 OH) and stearyl alcohol with 18 carbon atoms (C 18 H 37 OH) in a weight ratio of 3:2 (C MIX OH (3:2) with 5% STAC added as a cationic surfactant, and the specimen TP was positioned above the liquid level of the preservative treatment agent 900, resulting in the smallest shrinkage rate and good results. In addition, this C MIX When the preservative treatment agent 900, which is made by adding 5% STAC as a cationic surfactant to OH (3:2), is dripped onto the test specimen TP from above, and the test specimen TP is positioned above the liquid level of the preservative treatment agent 900, the preservation period is about 10 days, which is significantly shorter than the conventional period of about 20 weeks or about 5 months.

[0061] As shown in Table 3, the preservative 900 is a higher alcohol containing 16 carbon atoms, cetyl alcohol (C 16 H 33 OH) with 5% STAC added as a cationic surfactant, and the specimen TP was positioned above the liquid level of the preservative treatment agent 900, it was found that the shrinkage rate upon drying was slightly larger than that shown in Table 3, and the overall shrinkage rate was also slightly larger.

[0062] As shown in Table 4, the preservative 900 is a higher alcohol containing 16 carbon atoms, cetyl alcohol (C 16 H 33 OH) and stearyl alcohol with 18 carbon atoms (C 18 H 37 OH) in a weight ratio of 3:2 (C MIX OH (3:2) with 5% STAC added as a cationic surfactant, and the lower part of the specimen TP was always immersed in the preservative 900 while the upper part was exposed from the preservative 900. Although the shrinkage rate was slightly lower than in the case shown in Table 2, the results were still somewhat good.

[0063] In other words, a comparison of the treatment results shown in Tables 1, 2, and 3 reveals that when a cationic surfactant is added as the preservative treatment agent 900, direct impregnation of the test specimen TP (water-soaked excavated wood) is possible. Furthermore, a comparison of the treatment results shown in Tables 2 and 3 reveals that using a mixture of two types of higher alcohols in the preservative treatment agent 900 is more effective in suppressing shrinkage than using only one type. Furthermore, a comparison of the treatment results shown in Tables 2 and 4 reveals that it is more effective to position the entire specimen TP (water-soaked excavated wood) above the liquid level of the preservative 900, rather than having the lower part constantly immersed in the preservative 900 and the upper part exposed to the preservative 900.

[0064] C as higher alcohol MIX OH (3:2) mixed with STAC as a cationic surfactant. MIX The results showed that OH (3:2) had superior elasticity and plasticity when cooled and solidified compared to when STAC was mixed with OH (3:2) without STAC, or when STAC was mixed with cetyl alcohol or stearyl alcohol alone. That is, higher alcohol C MIX It has been confirmed that water-leached excavated wood WD preserved with preservative 900, a mixture of OH (3:2) and the cationic surfactant STAC, is less brittle, making it more resistant to minor impacts and reducing the risk of breakage of small parts such as splinters.

[0065] In addition, although the efficiency will be reduced, it is possible that a certain amount of moisture in the water-leached excavated wood WD will be replaced by the higher alcohol in the preservative treatment agent 900 simply by immersing the water-leached excavated wood WD in a partially exposed state. That is, as shown in Figure 4, the preservative treatment agent 900 is stored in the impregnation container 100, the inside of the impregnation container 100 is dried, and the water-leached excavated wood WD is immersed in the preservative treatment agent 900 with a part of it exposed. As a result, the moisture inside the water-leached excavated wood WD (the solute) evaporates, and at the same time, the higher alcohol (the solute) rises from the preservative treatment agent 900 into the water-leached excavated wood WD and is absorbed, replacing the moisture.

[0066] Furthermore, in the above embodiment, the impregnation container 100 as a semi-closed treatment tank is installed inside the thermostatic bath 400, but the preservative treatment agent 900 may be stored directly in the thermostatic bath 400 itself without using an impregnation container 100 or the like.

[0067] In addition, in the above embodiment, a dehumidifier 320 and an air pump 330 are used, but it is also possible to configure the dehumidification exhaust pipe 321 so that the end thereof is open to the atmosphere outside the thermostatic chamber 400 without using these.

[0068] Furthermore, it has been stated that either cetyltrimethylammonium chloride or stearyltrimethylammonium chloride may be used as the cationic surfactant, but it is also considered that cetyltrimethylammonium bromide or stearyltrimethylammonium bromide, in which the chloride ion (Cl-) is replaced with a bromide ion (Br-), may also be used.

[0069] In another embodiment of the present invention, the preservation treatment method for water-leached excavated wood involves dripping the preservative treatment agent 900 from above the water-leached excavated wood (test specimen TP). However, the method may also involve simply immersing the water-leached excavated wood WD (test specimen TP) in the preservative treatment agent 900, and then cooling it to solidify the preservative treatment agent 900.

[0070] In particular, C MIXIt was found that better results could be obtained by immersing the water-leached excavated wood WD (specimen TP) in preservative 900, which was prepared using a 3:2 mixture of hydroxybenzoates and OH with 5% STAC added as a cationic surfactant, with the fibers not positioned horizontally, and then heating the preservative 900 to a temperature above its melting point but below its flash point, and then cooling it.

[0071] Since the water in the test specimen TP has a higher specific gravity than the higher alcohol, it moves downward due to gravity and escapes from the bottom of the test specimen TP as bubbles, and it is thought that the preservative treatment agent 900 penetrates from the top surface of the test specimen TP in proportion to the amount of water that evaporates from the test specimen TP.

[0072] Table 6 shows the C MIX This shows the results of immersing specimen TP in preservative treatment agent 900, which uses OH (3:2) and contains 5% STAC as a cationic surfactant, and then heating it to 140°C. The treatment time was 8 hours.

[0073] [Table 6]

[0074] A preservation method for water-leached excavated wood in which the preservative treatment agent 900 is dripped from above takes about 10 days, but if the water-leached excavated wood (specimen TP) is immersed in the preservative treatment agent 900 with the fibers not positioned horizontally, and the preservative treatment agent 900 is heated to a temperature above the melting point but below the flash point, and then cooled, the preservation time is reduced to 8 hours. This eight-hour processing time is significantly shorter than the approximately 20 weeks or five months required using conventional methods. However, this 8-hour treatment time is the result of treating test specimens TP, which were made from water-soaked zelkova wood actually excavated from archaeological sites and cut into pieces approximately 30 mm square. It goes without saying that the actual treatment time will vary depending on various conditions, such as the species, size, and state of deterioration (moisture content) of the water-soaked zelkova wood being treated for preservation. [Explanation of symbols]

[0075] 100 Impregnation container 110 Holding member 120 Lid 200 Circulation mechanism 210 Liquid transfer pump 220 Suction pipe 230 Drip Pipe 300 Humidification / dehumidification mechanism 310 Humidifier 311 Primary humidification pipe 312 Secondary humidification pipe 320 Dehumidifier 321 Dehumidification exhaust pipe 322 Dehumidification air supply pipe 330 Air Pump 340 Solenoid Valve 350 control section 360 Temperature and Humidity Sensor 400 constant temperature bath 900 Preservative treatment agents WD Water-leached excavated wood

Claims

1. This method for preserving water-soaked excavated wood is characterized by immersing the water-soaked excavated wood in a preservative treatment agent made of higher alcohol to which a cationic surfactant has been added in a partially exposed state, allowing the preservative treatment agent to penetrate into the water-soaked excavated wood while evaporating the water in the wood, and then cooling the wood to solidify the preservative treatment agent.

2. This method for preserving water-soaked excavated wood comprises immersing the excavated wood in a partially exposed state in a preservative treatment agent made of higher alcohol to which a cationic surfactant has been added, dropping the preservative treatment agent onto the exposed part of the excavated wood while evaporating the water in the excavated wood, allowing the preservative treatment agent to penetrate into the excavated wood, and then cooling the wood to solidify the preservative treatment agent.

3. A method for preserving water-soaked excavated wood in which a preservative comprising a higher alcohol and a cationic surfactant is dripped onto the wood from above, characterized in that the wood is held above the liquid level of the preservative.

4. 4. A method for preserving water-soaked excavated wood according to claim 1, 2 or 3, wherein the water-soaked excavated wood is placed so that its fibers are not horizontal.

5. A method for preserving excavated wood as claimed in claim 1, 2 or 3, characterized in that the preservation treatment chemicals and water-soaked excavated wood are placed in a semi-sealed treatment tank, and air with a low vapor pressure is blown into the semi-sealed treatment tank from within the semi-sealed treatment tank, while the inside of the semi-sealed treatment tank is humidified and dehumidified.

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