JPH0857810A - Bamboo plywood - Google Patents

Abstract

PURPOSE: To obtain a bamboo plywood by combining a plate material made of a split material obtained by splitting a green bamboo into small pieces without occurrence of distortion or warpage. CONSTITUTION: A green bamboo is cut to a predetermined length so that each cut part has a plurality of nodes. The cut green bamboo is peripherally splitted into a plurality of split materials. A large number of plate materials 24 each obtained by processing the split material into a plate are overlapped to form an intermediate plywood 34. A sheet 34A is formed by stripping the intermediate plywood 34 vertically to the overlapped surface thereof. A bamboo plywood 40 is obtained by a method in which a large number of sheets 34A are vertically laminated and bonded in three or four layers so as to cross each other with respect to the grain direction thereof.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a laminated plywood suitable for construction materials such as concrete formwork materials, and in particular bamboo plywood using a plurality of board materials processed from the small cut materials by dividing the thick and thick Moso bamboo into small pieces. It is about.

[0002]

Laminated plywood made of lauan is generally used as a formwork material. However, demand for this type of laminated plywood has dramatically increased, leading to depletion of forest resources and destruction of the global environment. There is a risk that this will cause forest resources to be protected and proper use of forest resources is desired.

Bamboo can be reproduced in a shorter time than wood (about 3
(Maturity in years), it has the advantage that it does not take much time for tree planting and subsequent management, and it has excellent strength such as durability and impact resistance, but Moso bamboo, which is particularly thick and thick, is not used much. It is in.

Therefore, in order to use bamboo material for plywood, insect control and alteration treatment such as removal of sugar contained in bamboo are required. For this reason, if an attempt is made to prevent insects and change the quality of the raw bamboo after splitting it, the split material will be twisted or warped, making plate processing difficult. In addition, when a board material processed from a large number of small pieces and having a width wider than the wall thickness of the raw bamboo is laminated to form a bamboo plywood so that the board surfaces overlap with each other, there is a problem that warpage occurs over time. There is.

[0005]

SUMMARY OF THE INVENTION In view of the above problems, the main object of the present invention is to combine a plate material formed of a split material obtained by dividing raw bamboo into small pieces so as not to cause twisting or warping. To provide plywood.

[0006]

In order to achieve the above-mentioned object, the present invention uses a split material obtained by dividing a raw bamboo cut into a predetermined length in the circumferential direction to obtain a raw material thinner than the thickness of the raw bamboo. A thin plate in which the split surface of bamboo appears on the plate surface is formed, and the directions of a number of thin plates are crossed with each other so that they are laminated in 3 to 5 layers and then bonded.

[0007]

According to the present invention, a large number of plate materials obtained from the split materials are aligned in the plate thickness direction and overlapped to form an intermediate plywood having the same width as the plate material and a predetermined width. The intermediate plywood is superposed and ground perpendicular to the plane (sliced parallel to the surface) to form multiple lamellas. Bamboo plywood is made by laminating a number of thin plates alternately in alternating directions and stacking them on top of each other in 3-5 layers.

By cutting (slicing) the intermediate plywood perpendicularly to the overlapping surface, the cut surface of the raw bamboo appears on the surface of the thin plate, that is, the overlapping surface and the surface of the bamboo plywood. In other words, in terms of wood, the surface corresponding to the grain appears on the superposed surface and the surface, and since the thin plate is thinly cut in the radial direction of the raw bamboo, warping and twisting after forming do not occur.

[0009]

1 is a plan sectional view of a raw bamboo, FIG. 2 is a perspective view of a split material obtained by dividing the raw bamboo, and FIG. 3 is a plan sectional view of a plate material obtained from the split material. In order to obtain the chopped material 14 from the raw bamboo 2,
After cutting the raw bamboo 2 to a predetermined length (1 to 2 m), a predetermined circumferential distance w is provided on the portion of the surrounding meat 4 over the entire length of the raw bamboo 2.
A large number of cuts 5 are provided toward the axis O by a saw at a distance (about 25 to 40 mm). Depth c of notch 5 is circumference 4
It is deeper than the wall thickness t of No. 2 and is shallower than the radius r of the raw bamboo 2.
In this way, the raw bamboo 2 is provided with a large number of notches 5, but the large number of knots 3 keeps the original shape, and the peripheral meat 4 is not deformed over time such as being twisted or warped. The raw bamboo 2 provided with the notches 5 is boiled for about 1 hour to remove sugars and the like (pentosean and lipids) from the bamboo, and then subjected to insect repellent treatment. Further, if necessary, it is immersed in an appropriate chemical liquid such as insect repellent liquid, antiseptic liquid, lubricating liquid or impregnating reaction type resin liquid.

The raw bamboo 2, which has been subjected to the above-mentioned pretreatment, is naturally dried for about 1 week. Further, the raw bamboo 2 is carried into a drying chamber and dried at a temperature of about 100 to 150 ° C. for about 24 hours to stabilize the shape of the raw bamboo 2 and reduce its weight. Take out the raw bamboo 2 from the drying room,
Allow to cool naturally for about 24 hours.

As shown in FIG. 2, if the barbs 3 are removed by, for example, driving a barbing stick into the inner space of the raw bamboo 2, the surrounding meats 4 are removed.
Are separated from each other to form the split material 14. Prior to obtaining the shredded material 14 from the predetermined length of raw bamboo 2, the shredded material 14 is not separated, but is joined to each other by the knotted meat 3, and is subjected to pretreatment such as de-saccharification and insect control. Therefore, the shape is stable, and it is possible to prevent deformation such as twisting or warping of the split member 14.

As shown in FIG. 3, the split material 14 obtained as described above is first processed by an automatic one-sided plane cutter (a disk-shaped rotary cutter similar to an end face milling machine) to the inner skin surface 24a and the outer skin surface 24b. Finished flat and parallel to each other, both sides 24c
Is flattened to form an elongated plate member 24 having a width w1 and a thickness t1. Here, the thickness t1 of the plate member 24 may be arbitrary.

The present invention was obtained as described above and is shown in FIG.
The intermediate plywood 34 shown in FIG. 4 is formed from the plate material 24 shown in FIG. 4, the intermediate plywood 34 is ground (sliced) into a large number of thin plates 34A, and the large number of thin plates 34A are crossed with each other in 3-5 layers. Then, the bamboo plywood 40 shown in FIG.

Therefore, a large number (10 to 50) shown in FIG.
A plate material 24 having a thickness t1 and a width w1
4b are aligned with each other so as to be superposed on each other and are bonded with an adhesive to manufacture the intermediate plywood 34 shown in FIG. A roll coater is used for the inner and outer skin surfaces 24a, 24b of a large number of plate materials 24, and a water-resistant adhesive such as a thermosetting resin such as a phenol resin, a melamine resin, a urea resin, or other plywood is used. Applying an adhesive and then a number of plates 2
4 with a predetermined width B (50 to 20
0 mm) and apply pressure from both sides to bond. In order to complete the adhesion, a large number of plate materials 24 are loaded in a high-frequency heating furnace in a pressurized state and heated at a temperature of 120 to 150 ° C. for 3 to 60 minutes. Thus, the intermediate plywood 34 having the predetermined length L, width B and thickness w1 is completed. Instead of high frequency heating, the adhesive may be cured by a hot press machine.

Then, as shown by a chain line in FIG. 4, the intermediate plywood 34 is superposed and cut (sliced) perpendicularly to the surfaces 24a and 24b, and a thin plate 34 having a predetermined thickness T (about 2 to 5 mm) is obtained.
A is manufactured. Both sides of the obtained many thin plates 34A are smoothed by belt sanders.

Next, as shown in FIG. 5, a large number of thin thin plates 34A are arranged side by side without a gap to form a first layer having a predetermined width B, and a large number of thin thin plates 34A are formed on the first layer in the front and back. A second layer having a predetermined length L is formed without being lined up. Similarly, the directions of the thin plates 34A are made to intersect each other and the upper and lower parts 3 to 3
After being laminated in five layers, they are adhered by the same adhesive as that described above.

In order to stack and adhere a large number of thin plates 34A with their directions crossing each other, an adhesive is previously applied to the surface of each thin plate 34A by a roll coater, and the thin plates 34A are superposed.
Press for 17 to 30 minutes with a cold press to temporarily bond.
Next, the bamboo plywood 40 is sandwiched between the heating plates of the multi-stage hot pressing machine, and heated under pressure for about 5 to 15 minutes to complete the bamboo plywood 40.

Generally, the plate member 24 is apt to be twisted with respect to the axis O of the raw bamboo 2 and is easily warped with respect to the outer skin surface 24b of the raw bamboo 2. However, the bamboo plywood 40 according to the present invention is not limited to each thin plate 34.
On the superposed surface and the surface of A, the side surface 24c of the plate material 24 (2.
The surface after finishing the cut 5 when it is divided into small pieces appears, and since the thickness T of the thin plate 34A is smaller than the wall thickness t of the raw bamboo 2, warpage is unlikely to occur and the shape is stable over time. There is.

In the embodiment described above, a large number of plate materials 24 obtained by dividing the raw bamboo 2 into small pieces are laminated in a block shape to form a thick intermediate plywood 34, and the intermediate plywood 34 is thinly cut and divided into a large number. Instead of making the thin plate 34A, each plate member 24 is cut (sliced) vertically to the inner and outer skin surfaces 24a and 24b to form a small plate having a predetermined thickness T (about 2 to 5 mm). The split plates are arranged side by side and the side surfaces (divided inner and outer skin surfaces 24a and 24b shown in FIG. 2) are adhered to each other, and the divided surface of the raw bamboo 2 is thinner than the wall thickness t of the raw bamboo 2 (side surface shown in FIG. 2). 24
A thin plate 34A in which c) appears on the plate surface may be manufactured.

[0020]

As described above, according to the present invention, a split material obtained by dividing raw bamboo cut into a predetermined length in the circumferential direction is used. The thin plates appearing in Fig. 3 are formed, and a number of thin plates are laminated in 3-5 layers above and below with their directions crossing each other and then adhered. The cut surface when the raw bamboo is split into the overlapping surfaces of the thin plates. (A surface perpendicular to the outer surface of the raw bamboo) appears and the thickness of the thin plate is thinner than the thickness of the raw bamboo, so that warp is unlikely to occur and a bamboo plywood with a stable shape over time can be obtained.

That is, since a large number of thin plates are stacked with their directions crossing each other, the warp of the bamboo plywood is suppressed, and the thickness of the thin plates is much thinner than the thickness of the raw bamboo. It can be suppressed.

[Brief description of drawings]

FIG. 1 is a plan sectional view of a raw bamboo used to obtain a plate material used for a bamboo plywood according to the present invention.

FIG. 2 is a perspective view of a slitted material obtained by splitting the same bamboo into small pieces.

FIG. 3 is a plan sectional view of a plate material obtained from the same split material.

FIG. 4 is a perspective view of an intermediate plywood obtained from the same plate material.

FIG. 5 is a perspective view of a bamboo plywood obtained by laminating thin plates obtained from the intermediate plywood.

[Explanation of symbols]

2: Haratake 3: Sectional meat 4: Peripheral meat 5: Notch 14: Split material 24: Plate material 34: Intermediate plywood 34A: Thin plate 4
0: bamboo plywood

Claims (3)

[Claims] 1. A thin plate in which a divided surface of the raw bamboo appears on the plate surface, which is thinner than the wall thickness of the raw bamboo, is formed from a small material obtained by dividing the raw bamboo cut into a predetermined length in the circumferential direction. Bamboo plywood, characterized in that the thin plates of 3) are laminated in 3-5 layers above and below with the directions of the plates crossing each other and then bonded. 2. A raw bamboo cut into a predetermined length is divided in the circumferential direction to form a plurality of split materials having a width wider than the thickness of the raw bamboo, and each split material is processed into a plate. An intermediate plywood is formed by adhering a large number of plate materials so that the plate surfaces overlap each other, and the intermediate plywood is superposed and split perpendicularly to the surface to form a plurality of thin plates. Bamboo plywood, characterized by being laminated in 3-5 layers above and below and then adhered. 3. The chopped material is made by cutting raw bamboo into a predetermined length having a plurality of knots, and cutting a plurality of longitudinal cuts by a saw in a peripheral portion of the cut raw bamboo at predetermined circumferential intervals. Set up,
The bamboo plywood according to claim 2, wherein the raw bamboo having the cuts is boiled and then naturally dried, and then the knotted meat of the raw bamboo is removed and separated.