JPH06254812A - Decorating method for timber and wood material - Google Patents

Abstract

PURPOSE:To foam a solid pattern such as an engraving-like pattern of good reproducibility without the generation of damage to the surface of a material to be processed. CONSTITUTION:A material W to be processed composed of a timber and a woody material is plasticized by press molds 1 and 3 and a solid pattern is formed in the decorating method. A material W to be processed is put in the wet and hot state and plasticized, and then this material to be processed is turned gradually into close to the given shape and plastic deformed while being dried by induction heating to form a drying set.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to wood by dielectric heating.
The present invention relates to a decoration processing method for wood materials. The decoration processing method of wood / woody material of the present invention is used for accessories such as jewelry boxes, furniture,
It can be applied to form a three-dimensional pattern (especially sculpture-like) on the surface of wood / wood products such as entrance doors and other fittings, wall materials and the like.

Here, the wood material includes plywood, laminated wood, laminated wood, hard board (hard fiber board), particle board and the like.

[0003]

2. Description of the Related Art Conventionally, carving by chisel or a numerical control (NC) router (woodworking) is used as a method for decorating the surface of wood and wood products used for furniture, sundries, etc. Machining with a type of milling machine was the mainstream.

However, the number of craftsmen is decreasing year by year in the hand carving process,
It is expected that it will not be industrially viable due to lack of successors. On the other hand, machining by NC router is two-dimensional (planar)
It shows some efficiency for simple patterns, but for complex three-dimensional (three-dimensional) patterns, it takes a lot of time not only for creating a program but also for cutting, and the machined surface becomes rough due to rotary cutting. Therefore, repairing by hand is necessary, and as a result, it takes longer than hand carving. For this reason, the decorating process for wood and wood products such as furniture and miscellaneous goods is currently limited.

[0005]

For this reason, some methods have been used to decorate wood and wood products by forming a three-dimensional pattern by hot pressing (pressing) molding with a mold. There is.

However, the plasticization of the wood / wood material is insufficient, so that the surface of the material is damaged, or the shape of the mold is not accurately reproduced (especially when the press pressure is released at a high temperature, deformation occurs). There was a problem such as part of being returned to the original).

In view of the above, the present invention is a method for decorating a wood / woody material in which a three-dimensional pattern is formed by hot press molding, in which there is no risk of damage to the surface of the processed product and the reproducibility is improved. It is an object of the present invention to provide a method for decorating a wood / wood material that can favorably (sharply) form a three-dimensional pattern such as an engraving pattern.

[0008]

The present invention is to solve the above-mentioned problems by the following constitution.

In a decorative processing method in which a processed product made of wood / wood material is plastically processed by press molding to form a three-dimensional pattern, the processed product is plasticized in a wet / heated state, and then the processed product is formed. The method is characterized in that a drying set is formed by a plastic deformation step of gradually approaching a set shape while being dried by dielectric heating.

[0010]

【Example】

 A. Hereinafter, the decoration processing method of the present invention will be described in detail.

(1) First, prior to press molding, a processed product made of wood / wood material is plasticized in a wet / heated state.

The reason why the wood / wood material is plasticized by wetting and heating is as follows.

Among cellulose, hemicellulose, and lignin, which are the main components of wood and wood materials, cellulose is
Its crystallinity is high, and the glass transition point (231 to 253 ° C.) is almost unchanged in both dry and wet states. On the other hand, the glass transition points of hemicellulose and lignin are 167 to 217 ° C and 134 to 23, respectively, in the dry state.
5 ° C, while 5% in the wet state
It is significantly reduced to 4 to 142 ° C and 77 to 128 ° C.
Therefore, the wet / heated wood / wood material becomes highly plastic as a whole.

Here, the heated state needs to be a temperature above the glass transition point of hemicellulose and lignin, and is usually set to 80 ° C. or higher. Also,
Wet condition usually means 80% relative humidity at room temperature (20 ° C)
Equilibrium Moisture Content of Wood / Woody Materials (15%)
It means more states. The water content is usually 16% or more, preferably 18 to 30%, more preferably about 20%, although it varies depending on the type of wood / wood material and the heating state. If the water content is too high, the drying time will be longer,
Not desirable from an energy saving standpoint.

As a method for bringing the wood / woody material into a wet / heated state, boiling water may be passed, but steaming with overpressure steam is preferable because the wet / heating can be easily performed. The steaming conditions are usually 100 to 130 ° C x 15
~ 30 minutes

(2) Next, the workpiece is subjected to a gradual change plastic deformation step of gradually approaching the set shape while being dried by dielectric heating to form a drying set.

At this time, microwave dielectric heating (2450 MHz) may be considered as the mode of dielectric heating, but high frequency dielectric heating (1 to 30 MHz) is preferable, and low frequency region around 10 MHz is particularly preferable.

When the processed product is subjected to the above-mentioned gradual change plastic deformation process to form a drying set, the plastic flow is combined with the water flow inside the wood due to the drying, so that the macroscopic flow of the wood structure is improved. It becomes possible, and large internal stress does not occur due to plastic deformation. Therefore, the decorative pattern faithful to the shape of the mold can be reproduced on the surface of the wood / wood material satisfactorily (sharp), and the elastic return of the decorative pattern does not easily occur and the sharp pattern is maintained for a long time. It

As a mode of gradually approaching the set shape, there is a method of continuously or stepwise reducing the inter-die gap, or a method of continuously or stepwise pressurizing. And the press pressure is usually 1 to 2 MPa,
The time from initial pressurization to the final set shape is usually 1
5 to 60 minutes.

When the processed product is thin (around 10 mm), it is desirable to perform dielectric heating drying under reduced pressure. This is because the work piece is sandwiched by the mold on both sides, and the release area for water escape on the side is relatively small. Here, the degree of vacuum is 1.33 to 33.2 kPa (10 to 250 torr).

The drying time for forming the drying set on the work piece after the gradual change plastic deformation step is usually 20 to 20.
40 minutes. B. The mode in the case of performing dielectric heating drying by a high frequency is shown in FIGS. Note that common parts in each drawing are denoted by the same reference numerals, and description thereof in later drawings may be omitted.

(1) FIG. 1 shows an example in which an upper die (decorative die) 1 and a lower die (decorative die) 3 also serve as electrode plates for high frequency dielectric heating. A high frequency power source 5 is connected to the upper mold 1 and the lower mold 3 which are polar plates. Then, a spacer 7 is attached to the lower mold 3 to regulate the processing thickness. An oil heater 9 for surface heating is embedded in each of the molds 1 and 3. Although not shown, an upper press platen and a lower press platen are arranged above and below the upper mold 1 and the lower mold 3, respectively. In addition, W is a processed product made of wood / wood material.

(2) In FIG. 2, the upper mold 1 and the lower mold 3 are formed of a dielectric material, and the upper mold 1 and the lower mold 3 are provided with electrode plates 2 and 4 above and below, respectively. It is arranged. Here, as the dielectric, a material such as fluororesin, talc porcelain, borosilicate glass, or alumina, which is almost non-polar and has a small dielectric loss, is desirable.

(3) FIG. 3 shows a configuration similar to that shown in FIG. 2, which is suitable for a thick workpiece, and only the upper die is arranged.

(4) When the method of the present invention is actually carried out, a multi-stage molding press structure in which the electrode plates, oil heaters, molds, spacers, etc. shown in FIGS. . Then, the press molding apparatus is operated under reduced pressure.

[0026]

The method of decorating a wood / wood material according to the present invention is such that a work made of wood / wood material is plasticized in a wet / heated state and then the work is subjected to dielectric heating. Since the drying set is formed by undergoing a gradual change plastic deformation step of gradually approaching the set shape while drying, the following operation / effect is exhibited.

In order to plastically deform the workpiece in a wet and heated state with a high degree of plasticity and gradually into a set shape, that is, to plastically deform the workpiece simultaneously with the flow of water due to drying, wood is used. Macroscopic flow is also possible in the structure, and large internal stress does not occur due to plastic deformation.
Therefore, a decorative pattern that is faithful to the surface of the mold can be reproduced well (sharp) on the surface of the wood / wood material.
Elastic return of the decorative pattern is unlikely to occur, and a sharp pattern is maintained for a long time.

That is, a decorated metal mold is interposed between the high-frequency heating electrode plates (the electrode plate and the metal mold can be used together), and the metal mold can be used at a stretch until it hits the spacer for determining the thickness. When the material is compressed and dried as it is, wood
There is a case where the wood material shrinks and a void is partially formed between the wood / wood material and the mold, which prevents the fine portion of the mold from being transferred. In order to prevent this, it is continuously pressed at a required pressure, or the mold is pressed stepwise against the wood / wood material according to the schedule, and in that state, the dielectric heating is continued to perform the forming process. This enables effective processing that takes advantage of the rheological behavior that the wood and wood materials become extremely plastic when the water content changes under stress, and the accuracy of adhesion to the decorative processing die is improved. Good decoration processing is completed.

Therefore, according to the method for decorating wood / woody material of the present invention, there is no possibility that the surface of the workpiece will be damaged when a three-dimensional pattern is formed by hot press molding.
In addition, it is possible to form a three-dimensional pattern such as a sculpture-like pattern having good reproducibility, sharpness, and almost no elastic return.

[0030]

[Test Example] A test example conducted to confirm the effect of the present invention will be described below.

(1) 125 (width) x 2 of each tree species shown in Table 1
About 50 (length) x 12 (thickness) mm board grain material, 1
Steaming treatment was carried out under the conditions of 20 ° C. overpressure steam (0.198 MPa) for 25 minutes. The average water content at that time was 40%.

(2) Using the decoration processing apparatus having the configuration shown in FIG. 1, decoration processing was performed according to the following specifications.

High-frequency oscillator: Output 3 kw, frequency 6.7 MHz, mold temperature (oil heater): 50 ° C. Decompression degree: 6.65 kPa (50 torr) Continuous pressurization condition: After 5 minutes, 10 MPa → 20 MPa /
30 minutes Drying time: 30 minutes (3) Then, the average water content of each test piece during the decoration process was measured.

When the plasticized wood is pressed with a mold and dried with hot air while being fixed, the equilibrium water content (10 to 12%) is lowered depending on the wood side or the drying condition, but it takes about half a day to one day. Needed.

On the other hand, according to Table 1 showing the drying process in the case of dielectric heating and drying, the wood being processed is blocked by the decorating mold, and although the portion where water evaporates is small, 2
The processing is completed in 0 to 30 minutes, which shows that the plastic decoration processing can be performed in an extremely short cycle by adopting this processing method.

A sharp three-dimensional pattern could be formed in any of the tree species.

[0037]

[Table 1]

[Brief description of drawings]

FIG. 1 is a model cross-sectional view showing an example of a decoration processing method for wood / woody material of the present invention.

FIG. 2 is a model cross-sectional view showing another example of the same.

FIG. 3 is a model sectional view showing still another example.

[Explanation of symbols]

 1 Upper mold 2 Electrode plate 3 Lower mold 5 High frequency power supply W Workpiece

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Soo Yamazaki 20-1 Kitakanyama, Otaka-cho, Midori-ku, Nagoya-shi, Aichi Chubu Electric Power Co., Inc. Electricity Technology Laboratory (72) Inventor Hideo Matsumura Chubu Electric Power Co., Inc., Electric Power Technology Laboratory, Technology Development Headquarters, 1-20-20 Kitakousan, Otaka-cho, Midori-ku, Aichi Prefecture (72) Inventor, Jiro Sone, Chuo Electric Power Co. Shizuoka Branch

Claims (3)

[Claims] 1. A decoration processing method for forming a three-dimensional pattern by plastically working a processed product made of wood / wood material by press forming, wherein the processed product is wetted and heated to be plasticized, A method for decorating a wood / wood material, characterized in that a drying set is formed by subjecting a work piece to a gradually changing plastic deformation step of gradually approaching a set shape while being dried by dielectric heating. 2. The method for decorating a wood / wood material according to claim 1, wherein the work is dried by dielectric heating in a reduced pressure state. 3. The induction heating is high frequency induction heating,
2. The wood material according to claim 1, wherein the high-frequency dielectric heating is performed by applying a high-frequency voltage between the electrode plates that also function as the mold.
How to decorate wood materials.