JPH10244516A - Composite board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composite board suited for the use as a construction material or a furniture member. SOLUTION: This composite board comprises wooden fiber layers 1, 1 arranged on the front face only or the front face and the back face and a wooden cut piece layer 2 arranged on the back face of the wooden fiber layer 1 of the front face or between the wooden fiber layers 1, 1 of the front/back faces. In this composite board, a resin adhesive other than a formalin resin is used as an adhesive to be added to a wooden fiber for molding the wooden fiber layers 1, 1. As the adhesive to be added to the wooden cut piece for molding the wooden cut piece layer 2, the resin adhesive other than the formalin resin is preferably used. The specific gravity of the wooden fiber layer 1 is higher than the specific gravity of the wooden cut piece layer 2 and is preferably 0.8 or higher.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite board used as a building material or a member for furniture.

[0002]

2. Description of the Related Art Generally, sawn timber, plywood, laminated veneer (LV)
L., LVB) and other wood boards are used in a wide variety of applications as architectural and furniture components, but since they have a certain fiber direction, they expand and contract due to the absorption and release of moisture, In particular, there was a problem that the expansion rate in the direction perpendicular to the fiber direction was large and the dimensional stability was lacking.

[0003] In addition, since there is a conduit groove on the surface, it is necessary to perform a base treatment such as a sealer treatment and a sealing treatment at the time of processing such as surface coating and paper sticking.

[0004] Furthermore, due to the recent depletion of high-quality trees, such wooden boards tend to be expensive. Therefore, wood chipboards made by bonding small pieces of wood are inexpensive materials suitable for effective use of resources. Attention has been paid to it.

[0005]

However, since the wood chipboard is obtained by bonding wood chips, the surface is very rough and it is difficult to make up the surface. Therefore, in general, a thick decorative sheet tends to be used, which is expensive.

[0006] In addition, the wood chipboard is a collection of wood chips having low surface peel strength and individually having complicated fiber directions.
The expansion and contraction due to the absorption and release of water is remarkable, and the decorative sheet is easily peeled or cracked. Furthermore, when a decorative sheet is adhered using a large amount of an adhesive such as urea resin or phenol resin to prevent this, a strong formalin smell remains. It was inside and uncomfortable.

As an improvement of such a wood chip board, there is known a three-layer board in which the wood chips of the front and back layers are dense and thin, and the wood chips of the central layer are coarse. This 3
The layer board has a certain surface smoothness compared to a single-layer wood chipboard, and the bending strength is improved,
It still has the fundamental disadvantages of wood chipboard as described above.

Further, if the wood chips of the surface layer are made short (fine) and thin in order to enhance the surface smoothness of the three-layer board, the bonding force (entanglement) between the wood chips becomes small, and the same applies. In order to maintain the bending strength, there is a problem that a large amount of adhesive is required.

[0009]

In view of the above situation,
The present inventor has conducted intensive studies to solve the problems of inexpensive wood chipboard, and as a result, has completed the present invention.

That is, according to the present invention, the wood fiber layer is provided only on the front surface or the front and back surfaces, and the wood chip layer is provided on the back surface of the front wood fiber layer or between the front and back wood fiber layers. A composite board characterized in that a resin adhesive other than a formalin-based resin is used as an adhesive to be added to wood fibers to form a wood fiber layer.

Preferably, a resin adhesive other than formalin-based resin is also used as an adhesive to be added to the wood chip to form the wood chip layer (claim 2). It is preferable that the specific gravity of the wood fiber layer is larger than the specific gravity of the wood chip layer. The specific gravity of the wood fiber layer is preferably 0.8 or more (claim 4).

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A composite plate according to the present invention will be described below with reference to the drawings.

FIG. 1 shows the structure of a composite board according to one embodiment of the present invention, in which wood fiber layers 1 and 1 are arranged on the front and back surfaces, and a wood chip layer 2 is arranged between them.

As the wood fiber layer 1, for example, Lauan,
Wood fiber layers obtained from hardwood materials such as kapole, chestnut and poplar or softwood materials such as pine, cedar and cypress as raw materials can be mentioned.

A comparison between softwood and hardwood is that wood fibers obtained from softwood have thin and long fibers and white wood, whereas wood fibers obtained from hardwood have coarse fibers and a color tone close to brown. .

[0016] Accordingly, even in the case of a wood fiber board obtained by adding an adhesive to wood fibers and drying the wood fiber, the wood fiber board obtained using softwood has a smooth surface and a white color.
As a subsequent surface makeup, it is suitable for performing a surface makeup treatment by painting or an adhesive makeup treatment for thin veneer, decorative paper or the like.

On the other hand, a wood fiber board using wood fibers obtained from hardwood has a rough surface and exhibits a brownish color. Therefore, the wood fiber board is not suitable for painting as a surface makeup and has an excellent anchoring effect exhibited by the rough surface. It is suitable for applying a veneer or a decorative paper to the surface by using the effect to perform a cosmetic treatment.

As described above, as the wood fiber layer 1, it is preferable to appropriately select and use a suitable one from softwood and hardwood depending on the use as a composite board.

As the wood chip layer 2, small wood, sawmill waste,
Wood chips obtained from raw wood cores, waste wood chips and the like are used. In addition, a wood chipboard obtained by adding an adhesive to a small piece obtained by cutting and crushing and hot-pressing it can be used.

The specific gravity of the wood fiber layer 1 is preferably larger than the specific gravity of the wood chip layer 2. Thereby, when an external force is applied to the surface of the composite board, in addition to the compressive strength of the wood fiber layer 1 having a large specific gravity on the front side, the tensile strength of the wood fiber layer 1 having a large specific gravity on the back side is further increased. 1, 1
Combined with the restraining force of the composite board, it exhibits excellent bending Young's modulus (rigidity), and the high strength composite board is achieved by arranging the wood chip layer 2 having a low specific gravity at the center to reduce the overall weight and cost. Is obtained.

Further, by setting the specific gravity of the wood fiber layer to be larger than the specific gravity of the wood chip layer, even when the wood chip layer formed using a formalin-based resin adhesive is used, The wood fiber layer blocks formaldehyde released from the shard layer, and the effect of preventing the composite board from escaping into the atmosphere is obtained. This effect is more remarkably exhibited by using a wood fiber layer having a specific gravity of 0.8 or more.

The specific gravity of the wood chip layer 2 is preferably smaller than that of the wood fiber layer 1 as described above.
It is preferably in the range of 1.05. Specific gravity is 0.
A composite board using a wood chip layer less than 25 has an insufficient bending Young's modulus, and using a wood chip layer having a specific gravity exceeding 1.05 reduces the total weight of the composite board. It is not preferable because it increases.

The composite board of the present invention is provided with a wood fiber layer 1 having a smooth surface which is stable against expansion and contraction caused by the absorption and release of moisture, and has excellent surface decorativeness.
Make-up by applying a decorative sheet such as a synthetic resin sheet or painting can be performed easily and well. When a synthetic resin sheet is used for a decorative sheet, an olefin resin,
It is preferable to use a resin that does not generate a chlorine compound gas even when burned, such as an acrylic resin, a polystyrene resin, and a polyester resin.

Further, the wood fiber layer has a good bending strength and a good surface compressive strength because the long and thin fibers are intertwined to form a layer. Therefore, the composite plate is excellent in bending strength and surface hardness while being lightweight and inexpensive to manufacture.

The method for manufacturing a composite board according to the present invention will be described. As shown in FIG. 2, a wood fiber production line and a wood chip production line obtain wood fibers and wood chips to which an adhesive is added, respectively. A wood fiber layer made of wood fiber with an adhesive added only on the front surface or the front and back surfaces was arranged, and the wood chip layer was disposed between the back surface of the front wood fiber layer or the wood fiber layer between the front and back surfaces. Thereafter, it can be manufactured by pressing and pressing to form an integrated adhesive.

Each step will be described in detail below. (Wood fiber production line) As wood fibers, softwood materials such as pine, cedar, cypress, etc. or hardwood materials such as Rawan, Kapole, chestnut, poplar, etc. are made into chips, which are defibrated according to a conventional method, and have a water content of 20% or less. Preferably, those dried to 10% or less can be used. These wood fibers are 1-30m long
Most of them have a m and a diameter of about 2 to 300 μm.
The wood fiber has a shape of a bundle of conduits, temporary conduits, or cells, and the cell wall around the fiber is often torn or cracked.

An epoxy resin-based adhesive,
A resin adhesive other than the formalin resin such as an isocyanate adhesive or a urethane resin adhesive is added and mixed.

The wood fiber to which the adhesive has been applied is put into a hot air duct and dried while blowing. The air blowing speed at this time is about 15 to 20 m / sec, but is adjusted over a wide range according to the specific gravity of the wood fiber, the feeding amount, the processing capacity of the preceding and following steps, and the like.

The wood fibers are blown by the hot air to a volume of 6 to 15
After being dried to a moisture content of about%, it is conveyed to the forming devices 3 and 3 (FIG. 3). (Wood chip production line) Small timber, sawn wood, raw wood core,
A wood chip made of small wood pieces is obtained by cutting and crushing and, if necessary, secondary crushing using a waste material chip or the like as a raw material. The shape of the wood chips is an arbitrary shape such as a chip shape, a flake shape, and a stick shape.

The wood chips are sorted as required, adjusted to a uniform size and shape, and dried to a water content of 6 to 15%.
Next, an adhesive is added to the wood chip and mixed. As the adhesive at this time, urea resin adhesive, phenol resin adhesive, melamine resin adhesive, epoxy resin adhesive, isocyanate adhesive, vinyl acetate resin adhesive, urethane resin adhesive, etc. Among these, it is preferable to use a resin adhesive other than formalin-based resin, such as an epoxy resin-based adhesive, an isocyanate-based adhesive, and a urethane resin-based adhesive.

The wood chip to which the adhesive has been applied is dried if necessary, and then conveyed to a forming device 4 (FIG. 3). (Forming hot pressing) The wood fibers and wood chips conveyed to the forming devices 3 and 4 by the respective lines are stacked and deposited as shown in FIG.
1. A three-layer mat consisting of a wood chip layer 2 at the center is formed.

After the three-layer mat is cut into an appropriate size by the cutting machine 5 and hot-pressed by the hot press device 6, the composite plate of the present invention is manufactured.

The shaping of the wood chip by the forming device 4 may be performed while giving an orientation to form an oriented wood chip layer.

Further, the composite board of the present invention is prepared by combining a wood fiber board and a wood chip board separately manufactured in advance according to a conventional method with a urea resin-based material so that the wood fiber board is arranged at least on the front surface or the front and back surfaces. It can also be manufactured by laminating via a phenolic resin-based or aqueous vinyl urethane resin-based adhesive, and then press-bonding with a hot press.

When a composite board is obtained by bonding and integrating a wood fiber board and a wood chipboard as described above, the wood fiber having an arbitrary specific gravity is adjusted by adjusting the temperature, pressure or time of the heat and pressure in the manufacturing process. Boards and wood chipboards can be used selectively. That is, the specific gravity of the wood fiberboard is 0.4
Any of the following soft fiber boards, medium fiber boards of 0.4 to 0.8 and hard fiber boards of 0.8 or more can be selected and used. Similarly, in the wood chip layer,
Select a wood chipboard with a specific gravity of about 0.3, a medium wood chipboard of 0.4 to 0.8, and a hard wood chip layer of 0.8 to 1.05 with an arbitrary specific gravity Can be used. According to this method, a composite board in which the specific gravity of the wood fiber layer 1 is set to be larger than the specific gravity of the wood chip layer 2 can be easily manufactured.

Further, since the thickness of the wood fiber layer 1 and the wood chip layer 2 can be freely adjusted, a composite board having the strength and weight required as a composite board can be easily obtained.

Alternatively, according to the present invention, the wood fiber layer 1
Is made of softwood, the wood shaving layer 2 is made of hardwood, or the wood fiber layer 1 is made of hardwood, and the wood shaving layer 2 is made of softwood. It is also easy to make the selection, and free selection according to the application is possible.

In the above, the wood fiber layer 1 is provided on the front and back surfaces.
1 has been described, and a three-layer composite board having a wood chip layer 2 between them has been described. However, depending on the application, a two-layered wood fiber layer 1 is provided only on the front surface, and the wood chip layer 1 is provided on the back surface. The present invention may be configured as a composite plate composed of:

Hereinafter, a preferred embodiment of the present invention will be described in order to explain the present invention more specifically. (Wood fiber production) 160 chips of radiata pine
The mixture was boiled at 7 ° C. and 7 kg / cm 2 for 5 minutes to perform degreasing and softening treatment. The chips were defibrated by a defibrator type refiner, and the obtained wood fibers were dried.

This wood fiber was put into a blender, and a wax sizing agent and a 10% isocyanate-based adhesive were added and mixed in the blender with respect to the wood fiber amount, and then conveyed to a forming apparatus. (Manufacture of wood chips) Raw radiata pine wood or waste material was charged into a flaker to obtain flake-shaped wood chips. After the wood chips were dried, they were sorted to obtain appropriate flake-shaped wood chips.

The wood chips were put into a continuous mixer, and 1% of a wax sizing agent and 8% of an isocyanate-based adhesive were added and mixed with the wood chips in the mixer, and then conveyed to a forming device. . (Mat formation / Hot pressing) The wood fiber and wood chips conveyed as described above are placed on a screen conveyor from the downstream side in the conveying direction of the conveyor from the wood fiber forming device 3, forming the wood chips. An apparatus 4 and a forming apparatus 3 for wood fiber are dropped on a screen conveyor by a square forming apparatus installed in this order, and a continuous 3 is laminated from the front side in the order of wood fiber / wood shavings / wood fiber.
A layer mat was formed.

The continuous three-layer mat is cut into a predetermined size by a cutting machine 5 in a width and a length, and then inserted into a hot press 6 and hot-pressed at 200 ° C. for 5 minutes, each having a length of 5 m.
A composite board having an overall thickness of 25 mm and a size of 3 ′ × 6 ′ was obtained, in which a wood cutting layer 2 having a thickness of 15 mm was disposed between the front and back wood fiber layers 1 and 1 having a thickness of m.

The specific gravity of the wood fiber layers 1 and 1 in the obtained composite board was 0.7, the specific gravity of the wood chipping layer 2 was 0.5, and the specific gravity of the entire composite board was 0.6. .

[0044]

According to the present invention, inexpensive wood chips are used,
By providing a wood fiber layer on the front surface or the back surface of this wood chip layer, the surface is smooth and the cosmetic properties are good, and the surface peel strength is also excellent. It is possible to provide an excellent composite board that solves problems such as expansion and contraction due to water absorption and absorption.

Since a resin adhesive other than formalin-based resin is used as an adhesive to be added to the wood fiber to form the wood fiber layer on the surface of the composite board or on the front and back surfaces, harmful formaldehyde is released into the atmosphere. This is useful for maintaining a good indoor environment. It is also preferable to use a resin adhesive other than the formalin-based resin as the adhesive to be added to the wood chip to form the wood chip layer, but a formalin-based resin adhesive was used as this adhesive. Even in the case, since the effect of blocking formaldehyde released from the wood chip layer is obtained by the wood fiber layer having a higher specific gravity than the wood chip layer, preferably having a specific gravity of 0.8 or more, Can be effectively prevented.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a composite board according to one embodiment of the present invention.

FIG. 2 is a view showing a manufacturing process of the composite board of the present invention.

FIG. 3 is an explanatory view schematically showing a line from forming to hot pressing in the manufacturing process of FIG. 2;

[Description of Signs] 1 Wood fiber layer 2 Wood chipping layer

Claims (4)

[Claims] 1. A method in which a wood fiber layer is provided only on the front surface or on the front and back surfaces, and a wood chip layer is provided on the back surface of the front wood fiber layer or between the front and back wood fiber layers. A composite board characterized in that a resin adhesive other than formalin-based resin is used as an adhesive to be added to the wood fiber. 2. The composite board according to claim 1, wherein a resin adhesive other than formalin-based resin is used as an adhesive to be added to the wood chip to form the wood chip layer. 3. The composite board according to claim 1, wherein the specific gravity of the wood fiber layer is larger than the specific gravity of the wood chip layer. 4. The composite board according to claim 1, wherein the specific gravity of the wood fiber layer is 0.8 or more.