JPH11114906A - Production of wood container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce wood containers inexpensively that have excellent strength and water proofness, which are free from a risk of causing environmental pollution, and which can be used as a disposable container as well. SOLUTION: A laminated sheet is produced by laminating a plurality of wood sliced veneers, including at least two wood sliced veneers laminated such that the directions of fibers thereof intersect each other, bonded to each other with an adhesive. The laminated veneers are then cold pressed. Then, after such cold pressing, the laminated veneers are heated and pressure formed under a high frequency. In a preferred form, the cold pressed laminated veneers are held between silicone or cellophane and heated and press formed, and in an additional process, a water proof treatment is provided on the surface of the laminated veneers after such heating and press forming. A tray-like wood container can be prepared which comprises a container main body and a circumferential edge integrally protruding from the main body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the field of wooden container manufacturing technology, and more particularly to a wooden container suitable for use as various trays utilizing natural wood, and a method for manufacturing the same.

[0002]

2. Description of the Related Art In order to properly maintain and manage natural trees, it is necessary to perform thinning, and thinnings are produced with the thinning, but their uses are limited. In addition, despite the increasing stockpile of coniferous forests centered on cedar wood in Japan, demand is currently stagnant. On the other hand, recently, concerns about environmental problems are being raised, and concerns about the future of the treatment of incombustibles such as industrial waste are increasing. The increase is a problem. Therefore, if a new product can be developed using wood such as cedar as a container, it can be treated at home as incinerated garbage, and no harmful gas will be generated. It is expected to do.

[0003] Although some tray-shaped containers made of a woody material have been found in the past, there are few integrally molded ones, and a side wall is separately fixed to a thin plate-shaped main body.
Alternatively, in many cases, the cut-out portion provided in a part of the thin plate body is bent to form a side wall portion, or the like, so as to form a container. Recently, a method of molding a wooden veneer and processing it into a container has also been proposed (JP-A-9-99412, JP-A-8-25301, etc.), but the molding process is complicated.

[0004] Further, these conventional wooden containers all have the disadvantage that they are easily torn in a direction parallel to the wood fiber, are easily broken by bending even in the lateral direction, and are severely cracked over time. May be
Its use is limited. In the integrally molded type container, cracks and burrs are often seen from the beginning, particularly in the curved portion, which is not preferable in appearance. Further, these conventional wooden containers are not sufficient in terms of waterproofness, and are not suitable for applications such as food trays containing a large amount of water.

[0005] In order to improve the properties of wood materials, impregnation with a synthetic resin and / or bonding of a synthetic resin layer before or after molding are performed. It would be possible to obtain a wooden container with improved performance, but it would complicate the manufacturing process, be costly, and would not be economical, and the use of synthetic resin could cause environmental problems. There is.

Further, recently, containers such as trays using bamboo as a natural material have come to be seen, but trays and the like which can be put to practical use using wood having lower strength and workability than bamboo have been found. There is no known technology that can be integrally manufactured.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a wooden container which is superior in strength and waterproofness and which can be used as a tray or the like without causing environmental pollution problems. It is to establish the technology that can be manufactured.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a method for bonding a plurality of wood slice veneers including at least two wood slice veneers laminated so that fiber directions intersect each other. A wooden board characterized by comprising a step of producing a laminate bonded with an agent, a step of cold-pressing the laminate at room temperature, and a step of heating and press-molding the cold-pressed laminate by applying high frequency. Provided is a method for manufacturing a container. In a preferred embodiment of the present invention, the laminate after the cold pressing is sandwiched between sheets of silicone or cellophane to perform heating and pressure molding. As another preferred embodiment, the method of the present invention further includes a step of subjecting the surface of the laminate to waterproofing after the molding under heat and pressure. Further, the present invention provides a tray-shaped wooden container which is manufactured integrally by the above-mentioned method and comprises a container main body and a projecting edge on the outer periphery thereof.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to manufacture a wooden container used as various trays or the like according to the present invention, a veneer obtained by thinly slicing wood is used, and first, a plurality of veneer veneers are laminated with an adhesive. Make a board. At this time, at least two pieces of wood slice veneers are arranged so that the fiber direction (grain) crosses each other, that is, if one direction of the container is the vertical direction and the direction orthogonal to it is the horizontal direction, at least one piece The sliced veneers are arranged and laminated so that the fiber direction is parallel (or substantially parallel) in the longitudinal direction, and the fiber direction of at least one other slice veneer is parallel (or substantially parallel) in the horizontal direction. . FIG. 1 illustrates a case where two wood slice veneers are laminated in the vertical direction and one in the horizontal direction to form a laminate. Although the number of laminations is not particularly limited, 2 to 5 sheets are preferable, and the thickness after lamination is 0.1.
9mm to 2.0mm is suitable for molding.

The wood constituting the sliced veneer used is
Both hardwoods and conifers may be used, but preferred examples include cedar, hinoki, spruce, bay pine, red pine, beech, drill, falcata and the like. The harvested timber as it is, or the dried timber, after increasing the moisture content to near the fiber saturation point, is processed to 0.2 mm to 0.7 mm,
Processed and dried (either artificial drying or natural drying, generally having a water content of about 10% to 25%) is used. The grain can be either straight grain or board grain. The width and length of the sliced veneer can be arbitrarily selected according to the size of the wooden container to be manufactured.

The wood slice veneer used in the present invention is generally a thin slice obtained along the longitudinal direction (extending direction) of a tree, and is used for producing bamboo containers. It is not a rotary veneer sliced along the circumferential direction of bamboo (such as "peeling off radish wigs"). If you try to make cedar or other wood into a rotary veneer in the same way as bamboo, the material is brittle and not sticky, and because it has many nodes, it is thin (for example, 0.5 mm).
Slicing tends to cause cracks, and current technology requires that the thickness be at least about 2-3 mm. However, this thickness makes it difficult to mold a container such as a tray. Therefore, the wood slice veneer used in the present invention is preferably sliced along the longitudinal direction (extending direction). A wooden container such as a tray is obtained by combining the following steps using such a wood slice veneer. Is easy to integrally mold.

In the present invention, the adhesive used for the production of the laminated board does not generate harmful substances after adhesion curing so as to be suitable for a container on which foods and the like are placed, and is used when the used container is discarded and burned. It is essentially composed of only carbon (C), hydrogen (H) and oxygen (O) so as not to generate incombustibles and harmful gases, and has elasticity after bonding so that it can be easily processed later. Use an adhesive. Preferred examples of the adhesive satisfying this condition include a modified vinyl acetate resin, an epoxy resin, a polyvinyl alcohol resin, and glucomannan. These adhesives may be used in such a small amount that the laminated sliced veneers are lightly adhered.

In the method of the present invention, the laminate thus obtained is cold-pressed at room temperature. The cold pressed process is carried out under a pressure of 5kg / cm ² ~10kg / cm ² until a slice veneer laminate will have a temporary bonding an intensity of about one another.

The laminated plate after the cold pressing is then placed in a mold having a desired shape and heated and pressed. As mentioned above in connection with the prior art, the wood is made of bamboo. The workability and strength are lower than those natural materials, and it is extremely difficult to mold as it is, and it has to be performed carefully over a long time. That is, wood has a heartwood and a sapwood (for example, in the case of cedar, a red portion (heartwood) and an outer white portion (sapwood)). The cell wall of the meristem is thick and thick, and the cell wall of the meristem from spring to autumn is thin and pale).
Due to the knots, the wood is very uneven as a material,
Processing is extremely difficult compared to bamboo, which is a fast growing and uniform material. In addition, wood has a short fiber length (the average of Moso bamboo is 1.6 mm, whereas even Japanese hardwoods, which have excellent processability compared to conifers such as cedar), are inferior in processability. Above, the strength is also low. For example, the tensile strength of cedar is about 900 kg / cm ² (Moso bamboo is 1800 kg / c
m ² ), bending strength about 650 kg / cm ² (1500 kg for Moso bamboo)
/ cm ² ), and wood materials are liable to crack or break in the process of molding. As a result of repeated studies, the present inventor has found that a rigid wooden container can be reliably formed without cracking or the like in a short time when the laminated plate configured as described above is cold-pressed, and then subjected to high-frequency heating and pressure molding. Found that it can be integrally molded.

That is, in the present invention, after the laminate is cold-pressed, 1) heated and pressed by a high-frequency wave, and then immediately heated and pressed by a normal hot-press, or 2) heated and pressed by a high-frequency press. Press molding or 3) Immediately after heating with high frequency, heat and pressure molding by high frequency press. Particularly, the method 3) is very preferable in that the entire molding time can be shortened. The applied high frequency generally uses a frequency of 5 to 30 MHz. As the high-frequency press, a dedicated high-frequency press device for heating the mold with high frequency may be used, but for convenience, an oscillator of the high-frequency heating device may be connected to a normal hot-press press mold and used. it can.

Thus, the heating and pressure molding in the present invention may be carried out by applying a high frequency to the laminate and / or while applying a high frequency to the laminate, and setting the heating temperature of the mold at 80 ° C. to 150 ° C.
℃, preferably 80 ℃ ~ 100 ℃, after sandwiching the laminate,
After slowly overlapping and confirming that the molds (male and female molds) are aligned, 1 kg / cm ^{2 to} 50 kg / cm ² , preferably 1 kg / cm ²
/ cm ² conducted by pressurizing it under a pressure of to 20 kg / cm ^2, thereby, in a very short time operation, the surface is flat (smooth), to obtain a wooden container of rigid (stiff) as a whole it can. Thus, the heat and pressure molding of the present invention is performed in a short time, and at 80 ° C. to 150 ° C., generally
It can be carried out at a relatively low temperature of 80 ° C. to 100 ° C., and can be molded at a pressure as low as about 1 kg / cm ² . This is because the high-frequency treatment heats and activates the wood tissue to facilitate molding, and uses an adhesive that has elasticity after bonding. It is understood that the material molded at low pressure tends to be rigid.

In manufacturing a wooden container such as a tray, which is the object of the present invention, by pressure molding, conventionally, particularly, a curved portion or a bent portion which forms a boundary between the bottom and the side wall of the container is cracked or crushed. Has been a problem. The present inventor has found that a wooden container free of cracks and cracks can be obtained by sandwiching both sides of the laminate with a member that improves the slip of the mold during heat and pressure molding to solve this problem. . Thus, in a preferred embodiment of the method of the present invention, heat and pressure molding is performed while sandwiching the cooled laminate with a sheet of silicone or cellophane. FIG. 2 shows a state of such a molding. A desired wooden container is obtained by pressing the laminated board 1 with the male mold 3 and the female mold 4 while holding the laminate 1 with a silicone sheet or a cellophane sheet 2. 5 is molded.

The wooden container manufactured by the above-described steps of the present invention has sufficient strength, does not crack even when bent, and is restored by moisture absorption as seen in ordinary wooden materials. There is no deformation. Furthermore, surprisingly, it has been confirmed that the wooden container of the present invention has considerable water resistance as it is, and does not allow water to permeate in a water immersion test for about one to two weeks. This is understood to be due to the structure in which the wood slice veneers are laminated via the adhesive such that the fiber directions intersect each other. Therefore, for example, as a food tray of a fast food restaurant, it can be used as it is as a water-resistant (waterproof) container.

However, the surface of the laminate may be waterproofed, especially in applications where it is to be used over a long period of time and / or where frequent contact with moisture is expected. This waterproofing is carried out by coating a material having water resistance or water repellency and generally having heat resistance, such as a polyurethane or polypropylene laminate film, or by crimping a film of such a material.
At the time of painting, it is preferable to use a paint that does not emit volatile components after painting. Further, it may be coated with a biodegradable material such as a succinic polyester film.

The method of the present invention is particularly suitable for integrally manufacturing a tray-shaped (shallow dish-shaped) wooden container 8 having a container body 6 as shown in FIG. ing. The tray-shaped container obtained by the present invention makes use of the good texture of natural wood, and can be used for various purposes such as various trays, tableware, plates, stationery, office supplies, toys, and the like. It is applicable to both permanent (long-term) use and disposable (short-term) use. Note that the planar shape of the tray-shaped container is generally the same as that shown in FIG.
(Rectangle, square), but other shapes (for example, a circle) can be used as necessary.

[0021]

The following examples are provided to further clarify the features of the present invention, but the present invention is not limited to these examples. Example 1 Two straight-grain sliced cedar veneers processed to a material thickness of 0.5 mm were alternately laminated in the vertical direction and one in the horizontal direction using a modified vinyl acetate adhesive (KH1085, manufactured by Shoei Chemical Co., Ltd.).
After cooling at a pressure of 5 kg / cm ² for 10 minutes, the obtained laminate was subjected to a wood high-frequency dielectric heating device (RH-
(Type 3), a high frequency was applied for 7 seconds at a frequency of 27.1 MHz and a high frequency output of 3 kw. After high-frequency heating, the oscillator of this high-frequency heating device was connected to the mold of the hot press, and as a high-frequency press, the mold temperature was 100 ° C, the mold pressure was 1 kg / cm ² and the compression time was 15
Molding was performed under the conditions of seconds, and a tray-shaped wooden container (length 25 cm × width 16 cm × depth 2 cm) having a container body and an overhanging edge was integrally manufactured. Water was added for one week with the molding surface untreated, and the state of water seeping out from the bottom was observed.
No water could be identified.

EXAMPLE 2 Two straight grain sliced cedar veneers processed to a thickness of 0.5 mm were alternately laminated vertically and one laterally using a modified vinyl acetate adhesive for 10 minutes at 5 kg / cm. After cooling at ² , high-frequency heating was performed in the same manner as in Example 1, and molding was performed with a high-frequency press under the conditions of a mold temperature of 100 ° C., a mold pressure of 1 kg / cm ² , and a compression time of 10 seconds. The wooden container body and overhang can be manufactured. At this time, when a 0.5 mm thick silicon sheet was sandwiched between the mold and the sliced veneer, which was the raw material, and molding was performed, cracks and burrs were completely eliminated, and moldability was improved.

Example 3 Two straight-grain slices of cedar processed to a thickness of 0.5 mm were alternately laminated vertically and one laterally using a modified vinyl acetate adhesive for 10 minutes at 5 kg / cm. After cooling at ² , high-frequency heating was performed in the same manner as in Example 1, and molding was performed with a high-frequency press under the conditions of a mold temperature of 100 ° C., a mold pressure of 1 kg / cm ² , and a compression time of 10 seconds. The wooden container body and overhang can be manufactured. At this time, when cellophane paper was sandwiched between a mold and a sliced veneer as a raw material, and molding was performed, cracks and burrs were completely eliminated, and moldability was improved.

Example 4 Two straight veneer slices of cedar processed to a thickness of 0.4 mm were alternately laminated vertically and one laterally using a modified vinyl acetate adhesive, and 5 kg / cm for 10 minutes. After cooling at ² , high-frequency heating was performed in the same manner as in Example 1, and molding was performed by a high-frequency press under the conditions of a mold temperature of 100 ° C., a mold pressure of 1 kg / cm ² , and a compression time of 10 seconds. The container body and overhanging rim could be manufactured. A heat-resistant film (polypropylene-based laminated film) was pressure-bonded to the surface of the molded product to obtain a waterproof wooden container.

Example 5 Two pieces of cedar sliced veneer processed to a material thickness of 0.5 mm were alternately arranged vertically in two directions and one in the horizontal direction using an epoxy adhesive (Sirenx 100, manufactured by Konishi Co., Ltd.). Lamination,
After cooling at 5 kg / cm ² for 10 minutes, high-frequency heating was performed in the same manner as in Example 1, and the high-frequency press was performed under the conditions of a mold temperature of 80 ° C., a mold pressure of 5 kg / cm ² , and a compression time of 15 seconds. As a result of molding, a wooden container body and an overhanging edge could be manufactured. A heat-resistant film was pressure-bonded to the molded product to obtain a waterproof wooden container.

EXAMPLE 6 Three sliced veneers of rice pine processed to a material thickness of 0.2 mm were three in the vertical direction and two in the horizontal direction using a modified vinyl acetate adhesive.
Sheet alternately laminated, 10 minutes, after cold pressed at 5 kg / cm ^2,
High-frequency heating is performed in the same manner as in Example 1,
Molding was performed under the conditions of a mold temperature of 100 ° C., a mold pressure of 10 kg / cm ² , and a compression time of 8 seconds. As a result, a wooden container body and an overhanging edge could be manufactured. Urethane coating of molded products (Kyushu Paint Co., Ltd.)
And Ure Gold 5050) to obtain a waterproof wooden container.

EXAMPLE 7 A modified vinyl acetate adhesive was applied to the middle surface of a cedar sliced veneer processed to a thickness of 0.6 mm and the top and bottom surfaces of a rice pine sliced veneer processed to a thickness of 0.2 mm. Two sheets in the vertical direction and one sheet in the horizontal direction are laminated alternately for 5 minutes, 5 kg / c
After cooling with m ² , high-frequency heating was performed as in Example 1,
With high frequency press, mold temperature 100 ° C, mold pressure 1kg / cm ² ,
When molding was performed under the condition of a compression time of 10 seconds, a wooden container body and an overhanging edge could be manufactured. A heat-resistant film was pressure-bonded to the molded product to obtain a waterproof wooden container.

Example 8 Two pieces of cedar straight grain slices processed to a material thickness of 0.4 mm were alternately arranged in the longitudinal direction and in the transverse direction alternately using a gel of glucomannan (manufactured by Wako Pure Chemical Industries, Ltd.). Laminated, 60 minutes, 10kg
After cooling at a pressure of / cm ² , high-frequency heating was performed in the same manner as in Example 1, and a high-frequency press was used to mold at a temperature of 80 ° C and a pressure of 20 kg / c
When molding was performed under the conditions of m ² and a compression time of 20 seconds, a wooden container body and an overhanging edge could be manufactured. The molded product was coated with a biodegradable film (manufactured by Showa Kobunshi, Bionole) to obtain a wooden container.

Example 9 Single-grained cedar slices of cedar processed to a material thickness of 0.5 mm were alternately laminated one by one in the vertical direction and one in the horizontal direction by using a modified vinyl acetate adhesive, and 5 kg / cm for 10 minutes. After cooling at ² , high-frequency heating was performed in the same manner as in Example 1, and molding was performed with a high-frequency press at a mold temperature of 100 ° C., a mold pressure of 1 kg / cm ² , and a compression time of 15 seconds. The wooden container body and overhang can be manufactured. A wooden container having waterproofness was obtained by applying a urethane coating to the molded product.

EXAMPLE 10 One straight grain slice of cedar processed to a thickness of 0.7 mm was alternately laminated one by one in the vertical direction and one in the horizontal direction using a modified vinyl acetate adhesive, and then 5 kg / cm for 10 minutes. After cooling at ² , high-frequency heating was performed in the same manner as in Example 1, and molding was performed with a high-frequency press at a mold temperature of 100 ° C., a mold pressure of 1 kg / cm ² , and a compression time of 15 seconds. The wooden container body and overhang can be manufactured. A heat-resistant film was pressure-bonded to the molded product to obtain a waterproof wooden container.

[0031]

According to the present invention, a wooden container can be manufactured by a simple process including a bonding and laminating process of a wood slice veneer and a die forming process. Therefore, a tray can be manufactured at a price equivalent to that of a styrene foam container. Etc. can be provided. In the wooden container obtained by the present invention, since wood and a small amount of flammable and harmless adhesive are adopted as raw materials, after use, it can be easily disposed of by incineration, burial, etc., thereby reducing industrial waste. . ADVANTAGE OF THE INVENTION According to this invention, the tray-shaped wooden container provided with the container main body and the surrounding rim can be integrally manufactured, The obtained wooden container has sufficient intensity | strength and shape retention, Furthermore, It has high waterproofness even when no surface treatment is applied.

[Brief description of the drawings]

FIG. 1 is a view showing a state in which a laminated board is manufactured by bonding wood slice veneers so that fiber directions cross each other according to the present invention.

FIG. 2 is a view showing a state in which a laminate is subjected to pressure molding according to the present invention.

FIG. 3 shows a typical example of a tray-shaped wooden container of the present invention.

[Explanation of symbols]

 6 Container body 7 Overhanging edge 8 Tray-shaped wooden container

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Ryohei Asakura, 1627-1 Tsufukuhoncho, Kurume-shi, Fukuoka Prefecture Sunflower Corp. 214 (72) Kazuo Hanada 1-13-13, Hakata-eki Minami, Hakata-ku, Fukuoka-shi, Fukuoka Fukupa Co., Ltd. Inside

Claims (4)

[Claims] 1. A step of producing a laminated board in which a plurality of wood slice veneers including at least two wood slice veneers laminated so that their fiber directions intersect each other with an adhesive, and the laminated board is subjected to room temperature. A method for producing a wooden container, comprising: a step of cold-pressing the laminate; and a step of heating and press-molding the laminated plate after the cold-pressing by applying a high frequency. 2. The method for producing a wooden container according to claim 1, wherein the laminated plate after the cold pressing is sandwiched between sheets of silicone or cellophane to perform heating and pressure molding. 3. The method according to claim 1, further comprising a step of subjecting the surface of the laminate to waterproofing after the heating and pressure molding.
Alternatively, the method for producing a wooden container according to claim 2. 4. A tray-shaped wooden container integrally produced by the method according to claim 1, comprising a container main body and a projecting edge on an outer periphery thereof.