Wood processing method and wood processed products

Abstract

To provide a wood treatment method capable of safely utilizing without anxiety, for table ware and an instrument for manufacturing food product.SOLUTION: Wood is impregnated with water by decompressing / compressing treatment to be brought into a water-saturated state, and then dried, and further is impregnated with water by decompressing / compressing treatment to be brought into the water-saturated state, in this state, the wood is immersed into a wood treatment agent containing fermentation residue such as sake lees and beer lees, or the wood treatment agent is applied to the wood. A period of this treatment is for one day to eight weeks. As the sake lees, sake lees of Japanese sake can be used. Or, beer lees and wine lees can also be used. By the wood treatment agent containing these fermentation residue, the amount of water-soluble component infiltrated in cell lumen is increased, and dimension stability and deformability of the wood can be improved.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a wood treatment method, a wood treatment agent, and a processed wood product, in particular to a wood treatment method in which wood is immersed in the wood. [Background technology]

[0002] One of the drawbacks of wood is that it shrinks as it dries, resulting in unstable dimensions. To prevent the shrinkage of wood cell walls that accompanies moisture loss, various methods of dimensional stabilization have been devised, including impregnation with various organic liquids.

[0003] Patent Document 1 describes a wood penetration aid that acts as a carrier to allow preservatives, insecticides, termite repellents, flame retardants, dyes, fragrances, synthetic resins, etc. to penetrate deep into wood by mixing aromatic hydrocarbons, lower alcohols, dimethyl sulfoxide (DMSO), and methyl isopropyl ketone. The wood penetration aid of Patent Document 1 does not require any equipment or materials for pressurized injection, and can penetrate deep into wood at low cost by simply treating the wood using a coating method, immersion method, or drilling injection method. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-245904 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the organic liquids used for wood impregnation treatment include, in addition to dimethyl sulfoxide as described in Patent Document 1, many other substances with high oral toxicity, such as sodium hydroxide, methylolphenol compounds, and aqueous ammonia, and therefore cannot be used safely and securely as tableware or food production equipment.

[0006] The present invention has been made in view of the above circumstances, and an object of the present invention is to solve the above-mentioned problems. [Means for solving the problem]

[0007] The wood treatment method of the present invention comprises immersing wood in a wood treatment agent containing fermentation residue. If the thickness of the wood is 3 mm or less, it is heated at 80 to 100°C for 1 hour or more, if the thickness of the wood is 3 to 5 mm, it is heated at 80 to 100°C for 3 hours or more, and if the thickness of the wood is 5 mm or more, it is subjected to pressure injection treatment at room temperature. It is characterized by: The wood treatment method of the present invention is characterized in that the wood treatment agent has a moisture content of 40 to 60%. The wood treatment method of the present invention is characterized in that the moisture content of the wood is 10 to 30%. 。 The wood treatment method of the present invention comprises immersing wood in the wood treatment agent. Pickle Before the wood is sunk, the wood may be impregnated with water by a reduced pressure treatment to bring the wood into a saturated state. The wood processing method of the present invention is characterized in that after the vacuum and pressure treatment, the wood is dried and then further impregnated with water by vacuum and pressure treatment to make it saturated with water. 。 The processed wood product of the present invention is characterized by being treated by the wood treatment method. [Effects of the Invention]

[0008] According to the present invention, a method for treating wood that can be used safely and securely for tableware and food production equipment can be provided by immersing wood in fermentation residue such as sake lees. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram of the preparation of fermentation retentate according to a second embodiment of the present invention. [Figure 2] 1 is a graph showing the relationship between the soaking time and the weight increase rate of sake lees according to Example 1 of the present invention. [Figure 3] 1 is a graph showing the shrinkage rate of wood immersed in water and sake lees for eight weeks according to Example 1 of the present invention. [Figure 4]1 is a graph showing the immersion conditions and the anti-shrinkage ability of immersion-treated wood according to Example 1 of the present invention. [Figure 5] 1 is a graph showing the change in anti-shrinkage capacity in the radial direction of immersion-treated wood due to the immersion treatment according to Example 1 of the present invention. [Figure 6] 10 is a graph showing the change in the radial anti-shrinkage capacity of immersion-treated wood by immersion treatment in sake lees and brewer's lees according to Example 2 of the present invention. [Figure 7] 10 is a graph showing experimental results of immersion time in warm water immersion and reduced pressure injection according to Example 2 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] First Embodiment During the period of rapid economic growth after the war, there was a major shift from wooden products to metal and plastic for household items such as wooden lunch boxes and rice containers, mainly due to the ease of hygiene management, high degree of freedom in shape, and ease of processing and mass production. However, in recent years, the experiential value that can be gained by using wood, such as comfort and the ability to form an attachment over time, has come to be valued. However, simply drying wood does not provide the same dimensional stability as metal or plastic. It also has little plasticity, making it difficult to process. To address this issue, wood treatment methods have been known for some time, in which the cell walls are swollen by impregnation with various organic liquids. However, the organic liquids that have been shown to have a swelling effect so far have been substances that are orally toxic or highly toxic, such as polyethylene glycol (PEG), sodium hydroxide, methylolphenol compounds, aqueous ammonia, and dimethyl sulfoxide.

[0011] For this reason, the inventors developed a safe and reliable wood processing method for tableware and food manufacturing equipment. While conducting a series of studies aimed at elucidating the functionality of oke and barrels and improving their manufacturing processes, they focused on changes in the physical properties of wood used in sake brewing vats. Brewing vats are large containers with capacities ranging from 10 koku (approximately 1800 L) to 30 koku, and even as large as 50 koku, and as such, the wooden components are naturally large. Therefore, wooden components exposed to sake ingredients and fermentation and regularly cleaned are likely to suffer from shape changes due to repeated drying and swelling. However, brewing vats have a long lifespan as containers, and it is not uncommon for newly constructed vats to be used for sake for several years to a dozen years, followed by over 100 years of use for miso or soy sauce, requiring maintenance such as re-tightening the bamboo bands and replacing components. It is known that wood interacts with glycols and organic acids to improve dimensional stability and plasticize the wood, and the inventors believed that this effect may also be related to the lifespan of brewing vats. Therefore, the inventors discovered that treating wood with fermentation residues, such as sake lees, which have been reported to contain large amounts of glycols and organic acids, can improve dimensional stability and plasticize the wood. After extensive experiments, they were able to complete the present invention. In Japan, which has a rich fermentation culture and a wood culture represented by traditional crafts, it is possible to provide a safe and secure wood processing method by combining fermentation residue (hereinafter, fermentation residue will also be simply referred to as "sake lees" as a representative example) with wood.

[0012] More specifically, the wood treatment method according to this embodiment is characterized by immersing wood in a wood treatment agent containing fermentation residuals or applying the wood treatment agent to wood. Specifically, in the wood treatment method according to this embodiment, wood is immersed in fermentation residues or applied to the wood to allow the active ingredients to penetrate deep into the wood. In this case, in this embodiment, rather than using the fermentation residues themselves, immersion in a wood treatment agent containing fermentation residues, which will be described later, or application of the wood treatment agent can also be applied to the wood in the same manner as immersion in fermentation residues or application of the fermentation residues.

[0013] Here, as described in the examples below, the wood used in the wood treatment method of this embodiment can be cedar (Cryptomeria japonica D. Don), which is functional and easy to process in various ways. Other wood that can be used in this embodiment include broad-leaved trees such as beech, horse chestnut, maple, and oak. It is also possible to use coniferous wood by subjecting it to the vacuum-pressure treatment, degreasing, and drying described below. Furthermore, bamboo, kenaf, and other herbaceous plants that have been compressed and molded can also be used. This wood may be a lacquerware base at the final finishing stage in the process of making a lacquerware base. Specifically, the wood can be lacquerware that has been dried and has been subjected to rough sawing, wood turning, and other cutting processes, but before the application of lacquer. In other words, wood that is ready for priming can be used. Alternatively, thin wood sheets for molding with a thickness of approximately 0.2 to 1.5 mm can also be used. Furthermore, any part of the wood can be used: heartwood, sapwood, or transitional wood. Here, the transitional wood in this embodiment refers to the part where sapwood transitions to heartwood. Furthermore, thin wood such as thinned wood, or parts with knots, can also be used.

[0014] In the wood treatment method according to this embodiment, it is preferable to use any one or any combination of the following as the fermentation residue contained in the wood treatment agent: sake lees, sake lees from precious sake, beer lees, wine lees, whiskey lees, etc. In this embodiment, a fermentation residue such as sake lees that complies with the Food Sanitation Act is used. It is preferable to use sake lees and / or kijoshu sake lees as this fermentation residue. Sake lees contain large amounts of water-soluble sugar alcohols, such as glycerol and ethyl α-D-glucoside, and sugar-derived organic substances as active ingredients, such as swelling agents. It is believed that these substances diffuse and penetrate into the interior of the wood and cell walls during soaking, resulting in dimensional stabilization and improved deformability. Kijoshu sake is made by replacing part of the water used during brewing with sake, and contains more direct reducing sugars than sake. Soaking the sake lees of kijoshu with organic substances containing such direct reducing sugars and sugar metabolites further improves dimensional stability and deformability. Since the dimensional stabilization and deformability improvement effects, costs, etc., vary depending on the type of sake lees and the type of sake brewery, it is preferable to select the optimal combination. In addition to sake and kijoshu, this embodiment can also use regional fermentation residues such as beer lees, wine lees, and whiskey lees, because these also contain sugars, proteins, lipid-derived organic matter, and the like.

[0015] The wood treatment method according to this embodiment is characterized in that wood is immersed in a wood treatment agent containing fermentation residuals or the wood is coated with the wood treatment agent, and then treated for a specific period of about 1 day to 8 weeks. The penetration effect of the wood treatment agent according to this embodiment improves at higher temperatures, where molecular diffusion is more active. This is because the penetration of water-soluble sugar alcohols and sugar-derived organic substances increases as a product of temperature and time. Specifically, among water-soluble sugar alcohols and sugar-derived organic substances, for example, glycerin has a boiling point of 290°C and ethyl glucoside has a boiling point of 395°C, which are much higher than that of water, so the higher the treatment temperature at atmospheric pressure, the better. For example, boiling the wood treatment agent can achieve the most rapid diffusion. For this specific period, if the above-mentioned thin wooden board for molding, having a thickness of about 0.2 to 1.5 mm, is immersed in fermentation residue at room temperature or boiled for 24 hours, the effect of stabilizing dimensions and improving deformability can be obtained. On the other hand, the thicker the wood or the less liquid-permeable the tree species, the longer this specific period should be. For example, lacquerware base wood such as horse chestnut, beech, or silver maple can be up to 10 mm thick and has lower liquid permeability than cedar. Therefore, to fully achieve the effects of improving dimensional stabilization and deformability, it is preferable to boil for two hours and then soak for a day and night, repeated about three times. It is also possible to use a chemical injection tube that reduces pressure and increases pressure, and this treatment can be completed for about 24 hours. As described above, the dimensional stability of wood can be improved by immersing the wood in a wood treatment agent containing fermentation residuals for 1 day to 8 weeks, or by applying the wood treatment agent to the wood and allowing it to penetrate for 1 day to 8 weeks. Furthermore, dimensional stabilization also contributes to improving the wood's deformability, making it less likely to break even when bent. In other words, deformability can also be improved.

[0016] Furthermore, as shown in the examples below, wood can be refrigerated and soaked for use in brewing vats (wooden vats for brewing) and storage barrels, and other fermented food production vessels. In this case, because the diffusion of the active ingredient is slow, the effect can be achieved within a specific period of 4 to 8 weeks. That is, in the examples below, the weight gain rate becomes constant within 1 week after immersion in fermentation residue, and the anti-shrinkage capacity (ASE) increases sharply within 2 to 4 weeks after immersion. Furthermore, after immersion for 4 to 8 weeks, the ASE reaches 40 to 75%, achieving an effect equivalent to dimensional stabilization achieved by conventional chemical modification treatments. This specific period can be adjusted as appropriate by selecting the method described above, such as temperature, pressure, whether or not vacuum / pressurization treatment is performed, and the blending of wood treatment agents, and similar effects can be obtained with a treatment time of 1 day to 8 weeks.

[0017] In the wood treatment method according to this embodiment, the wood may be saturated with water by impregnating it with water through a reduced pressure and pressure treatment before being immersed in the fermentation overflow. In addition, it is also effective to combine pretreatments that improve liquid permeability, such as various incision processes including laser incising, microwave heating, and lateral compression deformation processes. Furthermore, in the wood processing method according to this embodiment, the wood may be dried after the reduced pressure and pressure treatment, and then impregnated with water by further reduced pressure and pressure treatment until it is saturated with water. This vacuum and pressure treatment may be carried out, for example, by enclosing the wood plate in a vacuum and pressure impregnation device and carrying out the vacuum, pressure, and drying processes. The conditions for this may be conditions commonly known to those skilled in the art, such as a vacuum of 50 mmHg or less for 1 to 5 hours and a pressure of 0.1 to 2 MPa. This configuration allows the components contained in the fermentation residue that improve dimensional stability and deformability to penetrate more easily, regardless of the heartwood, sapwood, or intermediate wood of the wood, and is expected to penetrate the components evenly into the cell walls.

[0018] In the wood treatment method according to this embodiment, when low-temperature treatment is performed on fermentation residues, such as in fermented food production vessels, it is preferable to treat them at a temperature at which the fermentation residues do not freeze or spoil. The temperature at which freezing does not occur may be, for example, below 0°C, approximately -10°C, due to the freezing point depression caused by sugars contained in the fermentation residues. Lowering the temperature below this is not preferable because even small amounts of water remaining in the wood may freeze, potentially damaging cell walls. Alternatively, treatment at a higher temperature may be performed by adding a pH adjuster or a component with a preservative effect, such as ethanol or isopropanol. On the other hand, in the wood treatment method according to this embodiment, the same effect can be obtained by boiling the wood in the fermentation residue, i.e., treating at around 100°C under normal pressure. When immersing dried wood in the fermentation residue, volatilizing the ethanol, which has a dehydrating effect, allows the wood to be moistened by water and the glycols to penetrate more quickly, so boiling the fermentation residue and heating it to remove the residual ethanol is effective. In addition, the impregnation effect can be improved by gradually increasing the concentration of fermentation residue. This is thought to be because if high molecular weight organic matter is first adsorbed onto the wood surface, it will hinder the further diffusion of low molecular weight organic matter into the wood. It is also possible to carry out the treatment at higher temperatures and pressures. In this case, it is preferable to set the conditions so that the active ingredients contained in the fermentation residue do not decompose too much.

[0019] The wood treatment agent according to this embodiment is characterized by containing fermentation residues. That is, in this embodiment, it is also possible to provide a wood treatment agent containing fermentation residues. In this case, a fermentation residue with higher wood workability may be blended, and the aforementioned noble brew sake lees, beer lees, wine lees, whiskey lees, etc. may also be added. In this case, the fermentation residues may be provided in their raw state as a wood treatment agent, or in a refrigerated, frozen, or dried form. Alternatively, the fermentation residues may be crushed, and the solid components removed to extract only active ingredients such as water-soluble sugar alcohols, sugars, proteins, and lipid-derived organic matter, which may then be provided as a wood treatment agent. In addition, the wood treatment agent according to this embodiment may contain appropriate preservatives, emulsifiers, pH adjusters, carriers, etc. (hereinafter referred to as "preservatives, etc."). These preservatives, etc. may be ingredients that comply with the Food Sanitation Act, thereby ensuring greater safety and security. Furthermore, after the wood has been soaked in the wood treatment agent, it can be disposed of in the same manner as ordinary waste such as fermentation residues, and used, for example, as livestock feed or for industrial alcohol fermentation.

[0020] The processed wood product according to this embodiment is characterized by having been treated by the wood treatment method. The wood processing method of this embodiment makes it possible to obtain processed wood (hereinafter referred to as "processed wood products") that can be used for a variety of purposes. In other words, the wood processing method of this embodiment can be configured as not only a simple wood processing method but also a method for manufacturing processed wood products. The processed wood products of this embodiment can be used for lacquerware, thin wood boards for processing that require wood deformation, such as "bent wood boxes," thin wood boards for other molding, and compressed wood boards. Specifically, the processed wood products of this embodiment can be used, for example, for tableware and food production equipment. Among these, the tableware can be used for bowls, trays, chopsticks, chopstick holders, lunch boxes, and various other types of tableware used daily. In addition, because the dimensional changes caused by temperature are suppressed, the processed wood products produced by the wood processing method of this embodiment can be used in dishwashers, microwave ovens, etc. Furthermore, as food production equipment, the material can be used for brewing vats (wooden brewing vats) used for fermenting sake, miso, soy sauce, etc., as well as for storage barrels and other brewed food production containers and food processing containers. Wooden brewing vats have moisture and humidity regulation functions due to their hydrophilic lignocellulose components, temperature regulation functions due to the porous nature of the wood, and are capable of colonizing lactic acid bacteria, yeast, and other bacteria. In particular, the wood treatment method of this embodiment allows components derived from fermentation residues to penetrate the wood, stabilizing it in a swollen state. This indicates that brewing vats used for brewing are less likely to shrink due to repeated wetting and drying, and the use of bamboo bands can reduce abnormal deformation associated with the vat being re-tightened or dried.

[0021] Furthermore, by applying a waterproofing treatment using lacquer or the like to the processed wood product of this embodiment, it is possible to prevent the leaching of active ingredients derived from the fermentation residue that contribute to dimensional stabilization, as will be shown in the examples described below. Furthermore, after the wood treatment of this embodiment, the processed wood product of this embodiment can be subjected to fumigation, heating, pressurization, the addition of polyphenols, or the like to denature the components contained in the fermentation residue that have penetrated into the interior, thereby improving processability and preventing the leaching of sugar-oil-based ingredients after processing.

[0022] The above configuration can provide the following effects. Conventional wood treatment methods use toxic organic compounds, making them unsafe for use on tableware, fermented food manufacturing vessels, tableware, etc. In contrast, the wood processing method of this embodiment uses food-safe fermentation residues to suppress shrinkage associated with drying and improve deformability, ensuring safety and security during processing. Furthermore, food-safe substances like fermentation residues can be used to suppress shrinkage associated with drying, allowing for safe and secure processing techniques. This ensures the safety and security of tableware, fermented food production vessels, tableware, etc., and also provides safety and security for use as tableware and food production equipment. Furthermore, by achieving dimensional stabilization of wood through safe wood processing, it will be possible to contribute to the expansion of wood use in the fields of tableware and food processing equipment, which have not been put to practical use until now. For example, it will enable wooden processed products to be dishwasher safe and microwave safe.

[0023] Another example of containers that have seen a significant shift from traditional wood to other materials such as stainless steel and enamel is brewing vats and storage barrels, which are used for fermenting and brewing food products such as sake, miso, and soy sauce. However, in recent years, consumer preference for sake has shifted from quantity to quality, and the proportion of designated sake such as ginjo sake and junmai sake in total domestic shipments has been increasing. However, the use of wooden vats for brewing continues as an essential part of the time-consuming sake brewing process. In regions with a thriving fermentation culture, there is demand for wooden vats for brewing, and there is growing interest in building and maintaining local supply systems for wooden vats and manufacturing techniques. However, the number of large vat manufacturers in Japan is decreasing, and maintenance and management are becoming issues in addition to new production.

[0024] In contrast, in this embodiment, the functionality of food manufacturing containers and food processing containers can be improved by impregnating wood with a wood treatment agent containing fermentation residues. Additionally, the dimensional stabilization of the wood components by immersing them in fermentation residues contributes to improved durability. This is expected to facilitate the maintenance and management of large fermentation vats, the number of which is decreasing in domestic manufacturers. Furthermore, the establishment of yeast and bacteria contained in fermentation residues is expected to provide more "tasty" fermented foods.

[0025] Second Embodiment (Preparation of fermentation residue and moisture content) Using FIG. 1, the adjustment of the moisture content of the wood treating agent according to this embodiment will be explained using sake lees as an example. First, an example of preparing a solution containing sake lees for impregnation into wood as a wood treatment agent according to this embodiment will be described. Sake lees include, for example, "plate lees," which are separated into plates when the sake is pressed; "loose lees," which are sake lees that could not be separated into plates; and "kneaded lees," which are loose lees and sake lees that have been aged at low temperatures for one to several months. The wood treatment agent according to this embodiment can be prepared by adjusting the moisture content of these lees, either raw or with the addition of water, by heating or other methods. In this case, grinding the solid content (brewer's rice) in a mixer or other device to form a paste makes the fluidity uniform and makes it easier to handle.

[0026] The wood treatment agent according to this embodiment is characterized by having a moisture content of 40 to 60%. The moisture content of sake lees varies greatly depending on the form of supply on the market. However, whether kneaded or sheet lees, adjusting the moisture content to 40-60% (average 50%) provides a stable, high impregnation effect. If the moisture content is 60% or higher, the concentration of the active ingredients in the sake lees will be low, resulting in reduced effectiveness. On the other hand, if the moisture content is lower than 40%, the diffusion rate due to moisture transfer will decrease, requiring a long impregnation time. Figure 1 shows an example where the moisture content was reduced to 50% by heating at 105°C for about 3 hours.

[0027] (Impregnation treatment conditions for fermentation residue) The moisture content of the wood to be immersed (impregnated) or coated with the wood treatment agent according to this embodiment may be from 0 to 150%. Of these, it is particularly preferable that the moisture content of the wood according to this embodiment is 10 to 30%. This is because, as will be shown in Example 2 below, when hot water treatment or vacuum / pressurization treatment is performed, it is better to have less water in the wood and more voids. However, if the moisture content of the wood is 10% or less, the water will be absorbed first, slowing down the impregnation time. Furthermore, if the moisture content of the wood is 30% or more, the free water remaining in the cell walls will dilute the concentration of the sake lees, which may slow down the impregnation time. Furthermore, as for the part of wood to be used for nystagmus treatment, the sapwood of wood is more suitable for impregnation treatment than the heartwood, because further experiments by the present inventors have revealed that the heartwood has poor liquid fluidity.

[0028] Furthermore, it is not necessary to make the wood saturated with water by the reduced pressure and pressure treatment shown in the first embodiment described above, and to make the moisture content of the wood 30% or more. As will be described later, if the wood is only a few mm thick, water can be poured in at normal pressure, and the immersion treatment is also possible even with a moisture content of 10 to 30% on a dry basis.

[0029] The temperature when wood is immersed in the wood treatment agent according to this embodiment is characterized by being 80°C to 100°C. As shown in Example 2 below, in this embodiment, the impregnation conditions for the wood treatment agent are in the range of 5°C to 100°C, and the higher the temperature, the greater the amount of impregnation in a short period of time. Therefore, if heating is possible, a temperature of 80°C or higher is preferred.

[0030] When wood is immersed in the wood treatment agent according to this embodiment, if the wood is 3 mm or less in thickness, it is heated at 80°C to 100°C for 1 hour; if the wood is 3 to 5 mm in thickness, it is heated at 80°C to 100°C for 3 hours; and if the wood is 5 mm or more in thickness, it is subjected to pressure injection treatment at room temperature. In this embodiment, the optimal impregnation time for immersing wood in the wood treatment agent varies depending on the dimensions of the wood. Specifically, when the length in the fiber direction of the wood is approximately 300 mm, for a veneer with a thickness of 3 mm or less, heating at 80°C or higher for 1 hour or more is suitable because sufficient strength can be obtained. On the other hand, when the thickness of the wood is 3 to 5 mm, heating at 80°C or higher for 3 hours is suitable because sufficient strength can be obtained. Furthermore, when the thickness of the wood is 5 mm or more, pressure impregnation treatment (pressure conditions: 0.75 MPa, 1 hour or more) at room temperature provides a higher impregnation effect.

[0031] Although pressure injection treatment is effective even when the thickness is 5 mm or less, boiling is easier to install. The target weight gain rate can also be achieved if the time is taken, even at room temperature. Immersion at room temperature does not require additional equipment investment or energy, so it is preferable when it is acceptable to take a long time.

[0032] In this embodiment, the fermentation residue may be brewer's spent grain. There are three types of brewer's spent grain: malt feed, maltage, and dried brewer's spent grain. Malt feed is "fresh brewer's spent grain" with a moisture content of 70-90%, averaging about 80%. Maltage is "dehydrated brewer's spent grain" with a moisture content of 60-70%, averaging about 65%. Dried brewer's spent grain has a moisture content of 10-20%. In Example 2 described below, favorable results were obtained using malt feed with a moisture content of 85%. Similar effects are expected with maltage. However, since the quality of dried brewer's spent grains can change depending on the drying temperature, it is preferable to use dried brewer's spent grains of stable quality. As will be shown in Example 2 below, beer lees can be used in the same wood material conditions and impregnation conditions as sake lees. [Example]

[0033] Hereinafter, examples of the present invention will be described with reference to the drawings, but the present invention is not limited to these examples in any way.

[0034] [Experimental Method] (Test material) Akita Prefecture-grown cedar (Cryptomeria japonica D. Don) logs were prepared as test specimens. They were divided into heartwood, sapwood, and transitional wood (the area where sapwood transitions to heartwood), split into small pieces, and then naturally dried. Test specimens were then cut along the straight grain, measuring 4 mm thick (tangential direction, hereafter referred to as "T direction"), 15 mm wide (radial direction, hereafter referred to as "R direction"), and 100 mm long. For the vacuum-pressure impregnation treatment, the test specimens were impregnated with water at a pressure of 50 mmHg or less for 0.5 hours, and then pressurized at a pressure of 1.2 MPa for 3 hours. The weight and dimensions of the saturated test specimens were measured. Twenty specimens were used for each test, and the average values are shown below. The test specimens were then dried in a constant-temperature oven at 105°C, after which their dimensions and weights were measured. These were used as the initial dry weight and initial dry dimensions, respectively. From the dimensional change between the saturated state and the completely dry state, the shrinkage rate α in the T direction and R direction T , α R was calculated using the following formulas (1) and (2).

[0035] α T =(l Tf -l T0 )÷l Tf ×100(%) …… Formula (1) α R =(l Rf -l R0 )÷l Rf ×100(%) …… Formula (2) However, l T , l R : T-direction and R-direction dimensions, subscript f: saturated state, subscript 0: completely dry state. The test piece was subjected to the immersion treatment in a saturated water state after being impregnated with water again by the reduced pressure impregnation treatment. Two types of sake lees were used: Junmai sake lees and Kijo sake lees from Aramasa Sake Brewery Co., Ltd. The ingredients used for Junmai sake lees are rice and rice koji, while Kijo sake lees are rice, rice koji, and sake.

[0036] (immersion treatment) The amount of sake lees used was 10 times the volume of the test piece. The sake lees used were from the Yamamoto Gomei, Hokuroku, Aramasa Sake Brewery, and Saito Sake Brewery breweries in Akita Prefecture. Below, we will show an example where sake lees from these sakes are mixed in a specified ratio, and sake lees from Kijo Sake from these breweries are used. 3 Sake lees were placed in a polypropylene container, removing any air, and the test specimens were arranged so they did not touch each other. The container was then covered with sake lees and sealed with a silicone rubber lid. For comparison, test specimens immersed in ion-exchanged water (hereafter referred to as water) were also prepared. To minimize deterioration of the sake lees, the container was refrigerated at a set temperature of 5°C. Four test specimens were removed at intervals of 1, 2, 4, and 8 weeks. The surfaces of the removed specimens were wiped clean with paper towels, and their T-direction dimensions (lTS) and R-direction dimensions (lRS) were measured in a wet state. After pre-drying in a constant-temperature oven at 60°C for 3–4 days, the specimens were dried at 105°C until they reached a constant weight. The total dry weight (ws0), T-direction dimensions (lTS0), and R-direction dimensions (lRS0) after immersion were measured. The weight gain (WPG) was calculated from the initial total dry weight (w0) of the test specimen and the total dry weight (ws) after immersion using Equation (3). WPG=(W s0 -W0)÷W0×100(%)... Formula (3) Also, l TS and l TS0 The shrinkage rate α in the T direction of the immersion-treated test piece TS , l RS and l RS0 R-direction shrinkage rate α RS was calculated in the same way using equations (1) and (2).

[0037] (Elution treatment) As a leaching treatment, water was poured into the immersion-treated test pieces in a completely dry state using a vacuum pressure treatment, and after leaving them to stand for 24 hours, they were washed with running water and their weight and dimensions were measured in a wet state. They were then pre-dried at 60°C for 3-4 days, and then dried at 105°C until they reached a constant weight, and their weight and dimensions in a completely dry state were measured. The shrinkage in the T and R directions was calculated from the dimensional changes before and after the leaching treatment, in the same way as for the immersion treatment.

[0038] (Dimensional stability evaluation) The dimensional stability of the wood was evaluated as a relative value based on the dimensional change rate of untreated wood due to changes in the moisture content of the cell wall. In this example, the commonly used anti-shrinking efficiency (hereinafter referred to as "ASE") was used as an index to determine the change in dimensional stability of wood due to immersion treatment. ASE is expressed by equation (4) and was calculated in both the T and R directions. ASE=(α0-α S0 )÷α0×100(%) …… Formula (4) where α0 is the linear shrinkage rate of untreated material, α S0 : Indicates the linear shrinkage of the immersion and leaching treated material.

[0039] [Results and Discussion] (weight gain rate) Figure 2 shows the weight gain (WPG) rate due to the soaking process of sake lees. In this graph, the horizontal axis shows the soaking period (weeks), and the vertical axis shows the weight gain rate (%). Open circles, squares, and triangles (○, □, △) show the results for junmai sake, while filled circles, squares, and triangles (●, ■, ▲) show the results for kijo sake. Each circle represents sapwood, squares represent heartwood, and triangles represent transitional wood. As a result, regardless of the type of cedar part (sapwood, heartwood, transitional wood) or the type of sake lees (junmai sake or kijo sake), the weight increased rapidly one week after the start of soaking and remained almost constant thereafter. There was no clear difference between the parts, and the WPG tended to be greater with kijo sake lees than with junmai sake lees. As mentioned above, Kijoshu is made by replacing part of the water used during brewing with sake, and the presence of alcohol inhibits yeast growth and alcoholic fermentation. For this reason, the more sake added to Kijoshu, the more direct reducing sugars there is. In other words, the increase in the amount of water-soluble components infiltrating into the wood's cell lumen due to soaking in Kijoshu sake lees is thought to be the main reason for the increase in WPG. Furthermore, no clear differences were observed in the weight gain rates between parts. This is thought to be due to the reduced pressure treatment performed prior to the soaking process, which improved the permeability of the heartwood and intermediate wood.

[0040] (Dimensional stability) Figure 3 shows the shrinkage in the R direction (radial direction) and T direction (tangential direction) of wood immersed for eight weeks. Figure 3(a) shows the shrinkage (%) in the tangential direction, and Figure 3(b) shows the shrinkage (%) in the radial direction. The figures show the shrinkage measured for the heartwood, transitional wood, and sapwood of water (comparative example), pure rice sake lees, and precious sake lees, respectively. Compared to wood soaked in water, wood soaked in sake lees showed a decrease in R- and T-direction shrinkage, regardless of the location or type of sake lees. This indicates that sake lees contain components that maintain a certain degree of swelling of the cell walls, even when moisture is lost from the cell walls due to drying. Furthermore, the shrinkage rate was generally lower for Kijo sake lees than for Junmai sake lees, which is thought to be due to the influence of differences in the components contained in the sake lees. The sake lees used in this study did not contain additives such as supplementary acids or fermentation aids, and the observed decrease in shrinkage rate was due to components produced during the rice fermentation process using koji mold, lactic acid bacteria, and yeast. Sake contains large amounts of glycerol and ethyl α-D-glucoside, which are thought to have a dimensional stabilizing effect similar to polyethylene glycol (PEG).

[0041] Figure 4 shows the relationship between the anti-shrinkage capacity (ASE) of sake lees-soaked wood and the soaking period. Figure 4(a) shows the shrinkage capacity in the tangential direction, and Figure 4(b) shows the shrinkage capacity in the radial direction. In each graph, the horizontal axis shows the soaking period (weeks), and the vertical axis shows the shrinkage capacity (%). Open circles, squares, and triangles (○, □, △) show the results for junmai sake, while filled circles, squares, and triangles (●, ■, ▲) show the results for kijo sake. Each circle represents sapwood, squares represent heartwood, and triangles represent transitional wood. Regardless of the type of sake lees or the part of the cedar, ASE increased rapidly between two and four weeks after soaking and then stabilized thereafter. The WPG shown in Figure 2 stabilized one week after soaking, indicating that diffusion from the cell lumen to the cell wall required a certain amount of time. Among the types of sake lees, kijo sake lees tended to have a higher ASE, and differences between parts were unclear. ASE values were 40–60% in the T direction and 40–75% in the R direction. These values corresponded to those obtained by soaking with PEG1540 (average molecular weight approximately 1500) or PEG2000 (average molecular weight 1800–2000), a common dimensional stabilizer. Furthermore, since the ASE of acetylated wood, a typical chemically modified wood, is also approximately 40–75%, those skilled in the art can understand that sake lees soaking treatment can produce effects comparable to those of existing dimensional stabilization treatments.

[0042] Figure 5 shows the change in radial ASE (%) of immersion-treated wood due to leaching treatment. For sapwood, intermediate wood, and heartwood, the white areas show the results before leaching treatment, and the black areas show the results after leaching treatment. A 24-hour soak in water was confirmed to reduce ASE regardless of the type of sake lees or part of the meat. It is known that PEG impregnation treatment easily leaches out in precipitation during outdoor exposure tests, and it was predicted that the dimensional stabilization of wood treated with sake lees would also be primarily due to water-soluble components. Since ASE was maintained to a certain extent even in the leaching test in which excess water was added, a process called vacuum pressure injection, it was suggested that as the sake brewing process is repeated, components derived from sake lees are retained in the cedar materials used in the brewing vats, contributing to dimensional stabilization through repeated wetting and drying.

[0043] (summary) Using cedar, a material used for large barrels used in sake brewing, we soaked Junmai sake and Kijo sake for 1 to 8 weeks and examined the weight change and radial and tangential shrinkage rates when completely dried after storage. The following results were obtained: 1. Regardless of the type of sake lees or the part of the cedar, the weight gain rate became constant one week after soaking. 2. The anti-shrinkage activity increased rapidly and then stabilized within 2 to 4 weeks after immersion. Because it took time for the enzyme to diffuse into the cell wall, the change lagged behind the weight increase. After immersion for 4 to 8 weeks, the ASE reached a maximum of 75%, or at least 40%, demonstrating an effect comparable to that of existing chemical modification treatments. 3. The anti-shrinkage ability was reduced by the water elution treatment, and the water-soluble components in sake lees had a large effect on the anti-shrinkage ability. When the sake lees-derived components penetrated the wood, the cell walls swelled in the same way as water, and the swelled state was stabilized, reducing the shrinkage rate. [Example]

[0044] [Experimental Method] (Test material) Akita Prefecture-grown cedar (Cryptomeria japonica D. Don) logs were prepared as test specimens. After natural drying, the sapwood was cut into straight-grain specimens measuring 7 mm thick (T direction), 30 mm wide (R), and 100 mm long. As in Example 1, the specimens were saturated with water by impregnation under reduced pressure. The weight and dimensions of the saturated specimens were measured. Ten specimens were used for each test, and the average values are shown below. The specimens were then dried in a constant-temperature oven at 105°C, after which their dimensions and weights were measured and used as the initial dry weight and initial dry dimensions, respectively. The T-direction αT was calculated from the dimensional change between the saturated and dry states, as in Example 1. The specimens were subjected to the soaking process in an air-dried state. Malt feed (draft beer lees) with a moisture content of 85% was used as the brewer's lees. The sake lees used were the pure rice sake lees described in Example 1.

[0045] (immersion treatment) The amount of beer lees and sake lees used was 10 times the volume of the test piece. The sake lees used were from the Yamamoto Gomei, Hokuroku, Aramasa Sake Brewery, and Saito Sake Brewery breweries in Akita Prefecture. Below, we will show an example where sake lees from these sakes are mixed in a specified ratio, and sake lees from Kijo Sake from these breweries are used. 3Beer lees or sake lees were spread into a polypropylene container while removing the air, and the test specimens were arranged so that they did not touch each other. The container was then covered with sake lees and sealed with a silicone rubber lid. For comparison, test specimens immersed in ion-exchanged water (hereafter referred to as water) were also prepared. The specimens were refrigerated at a set temperature of 5°C and removed after one week. The surfaces of the removed specimens were wiped clean with a paper towel, and their T-direction dimensions (TS) in the wet state were measured. After pre-drying for 3-4 days in a constant temperature oven at 60°C, they were dried at 105°C until they reached a constant weight. The total dry weight and T-direction dimensions after immersion were measured.

[0046] (Dimensional stability evaluation) The immersion-treated test pieces in a completely dry state were injected with water using a vacuum pressure treatment, left to stand for 24 hours, then washed with running water, and the weight and dimensions in a wet state were measured. They were then pre-dried at 60°C for 3-4 days, and then dried at 105°C until a constant weight was reached, and the weight and dimensions in a completely dry state were measured. The T-direction shrinkage and anti-shrinkage capacity (ASE) were determined from the dimensional changes before and after treatment in the same manner as in Example 1.

[0047] [Results and Discussion] (Dimensional stability) Figure 6 shows the anti-shrinkage capacity (ASE) in the T-direction (tangential direction) of wood soaked for one week. The ASE of brewer's lees and sake lees was 40.6% and 43.8%, respectively. It was confirmed that brewer's lees had a dimensional stabilization effect almost equivalent to that of sake lees. Furthermore, for wood soaked in sake lees, the ASE of dry wood (Figure 6) was higher than that of water-saturated wood after one week of soaking (Figure 4(a)). This confirmed the effectiveness of soaking dry wood in sake lees.

[0048] (Immersion time for hot water immersion and vacuum pressure injection) Next, we tested cedar sapwood (30mm wide x 100mm long, hereafter referred to as "test specimens") of various thicknesses, immersing sake lees in warm water (room temperature immersion) and then injecting it under reduced pressure to determine the immersion time required to achieve a weight gain of 100%, which is sufficient for practical use and demonstrates an anti-shrinkage capacity of 40%. Test specimens for each immersion treatment were picked up and weighed at 0.5, 1, 2, 3, 4, 8, 12, 24, 48, 72, 168, 340, 720, and 1400 hours after immersion. The sake lees used and other experimental methods were the same as those in the above example.

[0049] The results are shown in Figure 7. Figure 7(a) shows the results when the specimens used were saturated wood (moisture content 200-260%), while Figure 7(b) shows the results when the specimens used were air-dried wood (moisture content 10-30%). For each of the processing conditions, where the optimum length of the sake lees handling process is short, we determined that a practical processing time of 3 hours or less is ideal, and the numbers in light text are shown as the preferred conditions.

[0050] Specifically, for both water-saturated and air-dried wood, when the specimen thickness is 5 mm or less, a higher temperature is preferable because it shortens the soaking time. For a thickness of 3 mm, a temperature of 80°C or higher and a soaking time of 3 hours for water-saturated wood and 1 hour for air-dried wood are preferable. In other words, even if the soaking temperature is the same, it is preferable to keep the moisture content of the wood at a dry state. In addition, for a thickness of 5 mm, it was found that the air-dried material was best soaked at a temperature of 80°C or higher for 3 hours. On the other hand, for saturated wood with a thickness of 5 mm or more, it takes 12 hours or more at 80°C, so reduced pressure injection, which can be completed in 3 hours, is suitable. Furthermore, for air-dried wood with a thickness of 8 mm or more, it takes 8 hours or more at 80°C, so reduced pressure injection is also suitable.

[0051] The target weight gain rate can be achieved if time is taken even at room temperature (normal temperature). Therefore, if it is okay to take a long time, immersion can be done at room temperature and normal pressure without requiring additional equipment investment or energy.

[0052] It goes without saying that the configurations and operations of the above-described embodiments are merely examples, and can be modified as appropriate within the scope of the present invention. [Industrial Applicability]

[0053] The present invention can produce wood products with anti-shrinkage properties by immersing wood in fermentation residue, and is therefore industrially applicable.

Claims

1. Immersing the wood in a wood treatment agent containing fermentation residue; If the thickness of the wood is 3 mm or less, heat it at 80°C to 100°C for 1 hour or more, If the thickness of the wood is 3 to 5 mm, heat it at 80 to 100°C for 3 hours or more, If the thickness of the wood is 5 mm or more, pressure injection treatment is carried out at room temperature. A wood processing method characterized by:

2. The wood treatment agent has a moisture content of 40 to 60%.

2. The wood processing method according to claim 1.

3. The moisture content of the wood is 10 to 30%.

3. The wood processing method according to claim 1 or 2.

4. Before immersing the wood in the wood treatment agent, the wood may be impregnated with water by a reduced pressure treatment to a saturated state.

4. The wood processing method according to claim 1, wherein the wood processing method is a lumber processing method.

5. After the vacuum and pressure treatment, the material is dried, and then impregnated with water by vacuum and pressure treatment to reach a saturated state.

5. The wood processing method according to claim 4.

6. Treated by the wood treating method according to any one of claims 1 to 5 A processed wood product characterized by:

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