JPH0425403A - Composite board and its manufacture - Google Patents

Abstract

PURPOSE:To upgrade surface smoothness and surface peeling strength by using inexpensive shaved wood pieces and providing woody fiber layers at least on the surface and back face of the shaved wood piece layer. CONSTITUTION:A composite plate is formed with woody fiber layers 1 and shaved wood piece layer 2. As for the woody fiber, needle-leaf tree material such as pine, cedar or white cedar (hinoki) or a broad-leaf tree material such as lauan, kapur chestnut or poplar is chipped and fibrillated and dried to the extent of 20% or less water content for use. As for the shaved wood piece, a small diameter tree, a waste sawn wood, a stripped core of material wood, waste chips or the like is used as a raw material, and the same is cut and crushed to provide small wood pieces. The small wood pieces are selected and dried, and then a bonding agent is added and mixed with said small wood pieces. The woody fiber layers and the shaved wood pieces conveyed to a forming device are laminated to form a three-layer mat composed of the woody fiber layers of the surface and back face layers and a shaved wood layers as the center. Said three-layer mat is cut into a proper size by cutter and not press molded to manufacture a composite board.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a composite board used as a building material or furniture member, and a method for manufacturing the same.

[Prior art and its issues]

Generally sawn wood, plywood, veneer laminate (L, V, L, , L,
Wooden boards called V, B,) are used for a wide variety of purposes as construction and furniture components, but because these have a fixed fiber direction, expansion and contraction occur due to absorption and release of moisture. In particular, the expansion coefficient in the direction perpendicular to the fiber direction is large and dimensional stability is lacking, and there are conduit holes on the surface, so surface treatments such as sealer treatment and sealing treatment are required when surface painting, paper pasting, etc. There were problems such as the need to apply

In addition, due to the recent depletion of good quality water, such wood boards tend to become expensive, so wood chip boards made by gluing small pieces of wood are attracting attention as a material that is inexpensive and suitable for effective use of resources. has been done. However, since wood chip boards are obtained by gluing wood chips together, the surface is very rough and it is difficult to apply decoration to the surface.Generally, a thick decorative sheet-like material is pasted and decoration is not applied to the surface. Therefore, it is expensive. In addition, since the surface peel strength is low and it is a collection of wood chips with individual fiber directions, the expansion and contraction due to absorption and release of moisture is significant, and urea and phenol resins and phenol resins tend to peel off and crack in decorative sheets. Since a large amount of adhesive such as resin is used, there is a strong formalin odor, and when used on furniture, etc., there is a problem that the formalin odor is trapped inside the furniture. As an improved version of such a wood chip board, a three-layer board is known in which the surface layer of wood chips is fine and thin, and the center layer is made of coarse wood chips. This 3 layer board is
The surface has a certain degree of smoothness compared to a single layer of wood chipboard,
Although the bending strength is improved, it still has the fundamental drawbacks of wood chip boards as mentioned above.Furthermore, in order to improve the smoothness of the surface layer, the wood chips on the surface layer are shortened (finely cut). ) If the wood chips were made thinner, the bonding force (entanglement) between the wood chips would be reduced, and a large amount of adhesive would be required to maintain the same bending strength.

[Means for solving problems]

In view of the current situation, the present inventor has completed the present invention as a result of intensive research to solve the problems of inexpensive wood chip boards.

That is, the present invention provides: l) A composite board having a wood fiber layer arranged only on the front surface or on the front and back sides, and a wood chip layer arranged on the back side of the front wood fiber layer or between the wood fiber layers on the front and back sides.

2) A wood fiber layer obtained by defibrating wood to which an adhesive has been added is arranged either on the front side only or on both sides, and an adhesive is added on the back side of the front wood fiber layer or between the front and back wood fiber layers. A method for manufacturing a composite board, in which a layer of wood particles obtained by cutting wood is laminated, then pressed together and bonded to form an integral piece.

3) A method for manufacturing fiberboard in which wood fiberboard is laminated on only the front surface of wood chipboard or on both sides using adhesive, and then the boards are pressed together.

With this structure, a composite plate with sufficient strength was obtained at an inexpensive price.

[Explanation of configuration]

The composite plate of the present invention will be explained according to the drawings.

FIG. 1 shows a composite board of the present invention, where (1) is a wood fiber layer and (2) is a wood chip layer.

Examples of the wood fiber layer (1) used in the present invention include wood fiber layers obtained using hardwood materials such as lauan, capor, chestnut, and poplar, and softwood materials such as pine, cedar, and cypress. . Comparing softwood and hardwood, the wood fibers obtained from each village are thin, long, and white in color, while hardwood has coarser fibers and is closer to brown in color. Wood fiberboard is obtained by hot pressing these wood fibers with adhesive added and dried.
Products made of coniferous wood have smooth and white surfaces, making them suitable for subsequent surface decoration by painting and adhesive decoration for thin veneers, decorative paper, etc. In addition, hardwood materials have a rough surface and a good anchoring effect, resulting in a brown color, so they are not suitable for surface decoration by painting or adhesive decoration for thin veneers, decorative paper, etc. Suitable for adhering veneer, decorative paper, etc. to the surface. This is because the anchoring effect of the surface improves adhesive strength, and the color of the material affects the decorative layer. Therefore, as the wood fiber layer, a suitable softwood material or hardwood material can be selected as appropriate depending on its use as a composite board.

As the wood chip layer (2), wood chips obtained from small-diameter wood, sawn waste, raw wood core, waste wood chips, etc. are used as raw materials. In addition, small pieces are obtained by cutting and crushing, and a wood chip board is used which is heat-pressed with the addition of an adhesive.

The composite board of the present invention is a surface material made of a wood fiber layer with a smooth surface that is stable against expansion and contraction due to absorption and release of moisture, and has good surface cosmetic properties, such as sheets such as PVC sheets, veneers, and decorative paper. It is possible to easily perform surface adhesion processing of shaped decorative materials, overlay processing by press molding, etc., surface painting processing, etc. In addition, the wood fiber layer has excellent bending strength and high surface compressive strength because the long and thin fibers are intertwined to form a layer. Furthermore, the wood particle layer between these wood fiber layers has a lower specific gravity and is cheaper than the wood fiber layer, so
As a composite board, it is lightweight, has excellent surface hardness and bending strength, and is inexpensive.

To explain the manufacturing method of the composite board of the present invention, as shown in FIG. After arranging a wood fiber layer made of wood fibers to which adhesive has been added on the front and back sides, and placing a layer of wood chips on the back side of the front wood fiber layer or between the front and back wood fiber layers, It can be manufactured by pressing and bonding and integrally molding.

Each step will be explained below.

(Wood fiber manufacturing line) As wood fiber, for example, softwood such as pine, cedar, cypress, or hardwood such as lauan, capor, chestnut, poplar, etc. is made into chips, and then defibrated according to a conventional method to have a moisture content of 20%. Below, it is preferable to use one dried to 10% or less.

These fibers have a length of 1-30cm and a thickness of 2-30cm in diameter.
The majority of cases are of a certain degree. These organic fibers are shaped like conduits, tracheids, or bundles of cells, and the cell walls at the outer periphery of the fibers are often torn or cracked.

A urea resin adhesive, a phenol resin adhesive, a melamine resin adhesive, an epoxy resin adhesive, an incyanate/vinyl acetate resin adhesive, or these modified synthetic resin adhesives are added and mixed to these wood fibers. The wood fibers with the adhesive attached are put into a hot air duct and dried while blowing air. The air blowing speed at this time is about 15-20 m/sec, but it can be adjusted over a wide range depending on the specific gravity of the wood fiber, the amount of feeding, the processing capacity of the previous and subsequent steps, etc.

The wood fiber layer is dried to a moisture content of 6-15% by blowing with this hot air.

The dried wood fibers are conveyed to a forming device.

(Wood chips manufacturing line) Small diameter wood, sawn waste, raw wood core, waste wood chips, etc. are used as raw materials, and wood chips are obtained by cutting, crushing, and, if necessary, secondary crushing. These wood pieces are sorted, arranged into uniform sizes and shapes, and dried to a moisture content of 6-15%. Adhesive is then added to and mixed with these wood pieces.

The wood chips to which the adhesive has been adhered are dried if necessary, and then transported to a forming device. The adhesive used in this case is the same as that used for the wood fiber layer.

(Forming hot pressing) The wood fiber layer and wood chips conveyed to the forming device by each line are deposited as shown in Figure 3, with the front and back layers consisting of a wood fiber layer and the center layer consisting of a wood chip layer. A three-layer mat is formed. A composite board can be manufactured by cutting this three-layer mat into an appropriate size using a cutting machine and hot-pressing the mat.

In addition, the composite board of the present invention is made of a wood fiber board and a wood chip board that have been separately manufactured in advance according to a conventional method, and are made of urea resin, phenol resin, etc. so that a wood fiber layer is disposed on at least the front surface or the front and back surfaces. The composite plate of the present invention can also be obtained by laminating the sheets using a vinyl urethane adhesive or an aqueous vinyl urethane adhesive, and then bonding them together using a hot press. In a composite board obtained by bonding and integrating a wood fiber board and a wood chip board, the wood fiber layer (1) has a temperature of heat and pressure during the manufacturing process,
By adjusting the pressure and time, its specific gravity can be reduced to 0.4 or less (
(soft fiberboard), o, a-o, a (medium density fiberboard) and 0.8 or more (hard fiberboard). Similarly, the specific gravity of the wood chip layer (2) can be reduced to 0.000 by adjusting the temperature, pressure and time of the hot pressure during the manufacturing process.
Around 3 (light wood particle board), up to 0.4-0.8 (medium layer wood particle board) and 0.8-1.05 (hard wood particle board),
Can be selected arbitrarily. Therefore, for example, by using hard fiberboard with a specific gravity of 0.8 or more as the front and back wood fiber layers, and selecting a middle layer wood particle board with a specific gravity of 0.4-0.5 as the middle wood particle layer, When an external force is applied to the front and back sides, the compressive strength of the wood fiber layer with high specific gravity on the front side, the tensile strength of the wood fiber layer on the back side, and the binding force of the wood fiber layer combine to provide excellent bending Young's modulus (rigidity). , a lightweight and strong composite board can be obtained. As described above, the composite board of the present invention can be obtained by freely selecting the specific gravity of the wood fiber layer and the wood particle layer and adjusting the thickness thereof to obtain a composite board having the required strength and weight. can.

The above explanation is about a composite board that has a wood fiber layer on the front and back sides and a wood particle layer in between, but depending on the application, the wood fiber layer may be placed only on the front side and the wood particle layer on the back side. A composite board consisting of two layers having .

〔effect〕

The composite board of the present invention uses inexpensive wood chips and provides wood fiber layers on at least the front and back surfaces of the wood chip layer, thereby achieving a smooth surface with good cosmetic properties and high surface peel strength. This is an excellent composite board that solves the problems of wood chip boards, such as expansion and contraction due to water absorption and moisture absorption.

In the method for manufacturing a composite board of the present invention, the composite board obtained by laminating and bonding wood fiberboard and wood chip board manufactured in advance is manufactured by arbitrarily adjusting the specific gravity and thickness of each board during the manufacturing process. Therefore, it is possible to obtain a composite plate having a weight and strength suitable for the purpose.

In addition, composite boards are manufactured by forming wood fibers and wood chips to which adhesive has been added to form a laminated mat, and then hot-pressing the wood fibers. The wood fibers and the wood chips are bonded, and the wood fiber layer and the wood chip layer are simultaneously manufactured as a single board, resulting in an extremely high bonding strength between each layer. Furthermore, by adjusting the amount of wood fibers and wood chips dropped from the forming machine when forming the mat, the thickness of the wood fiber layer and the wood chip layer can be adjusted freely.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 (Wood fiber production) Radiata pine chips at 160°C, 7 kg/+4
2 for 5 minutes to perform defatting and softening treatment.

The chips were defibrated using a defibrator refiner, and the resulting wood fibers were dried.

The wood fibers were put into a blender, and 4% wax size and 10% phenol resin adhesive were added and mixed with respect to the amount of wood fibers in the blender, and then conveyed to a forming device.

(Manufacture of wood chips) Radiata pine raw wood or waste wood was put into a flaker to obtain flaky wood chips. After drying the wood chips, they were sorted to obtain appropriate flaky wood chips.

The wood shavings were placed in a continuous mixer, in which 1% of the sizing agent and 8% of the phenolic resin adhesive were added and mixed with respect to the amount of the wood shavings, and then conveyed to a forming device.

(Mat formation, heat pressing) On the screen conveyor, from the downstream side in the direction of conveyance, there are a forming device for the transported wood fibers, a forming device for the transported wood shavings, and a forming device for the transported wood fibers. The wooden edges and wood chips were dropped onto a screen conveyor to form a continuous three-layer mat in which wood fibers/wood chips/wood fibers were laminated in this order from the surface side.

After cutting this wood shavings mat into the specified width and length, it was inserted into a hot press and hot-press molded at 200℃ for 5 minutes, so that the front and back wood fiber layers each had a thickness of 5cm, and the wood shavings 15 layers
A single-layer composite plate having a total thickness of 25 mm and a size of 3' x 6' was obtained.

The specific gravity of the wood fiber layer in the composite board was 0.7, the specific gravity of the wood chip layer was 0.5, and the specific gravity of the composite board as a whole was 0.6.

[Brief explanation of the drawing]

Figure 1: A perspective view of the composite board of the present invention, Figure 2: 2 showing the manufacturing process of the composite board of the present invention, Figure 3: An explanatory diagram of the manufacturing method as well. φ is a wood fiber layer, 2 is a wood particle layer, 3: Forming material, 4: Forming material, 5: Cutting material, 6: Hot press.

Claims (1)

[Claims] 1) A composite characterized in that a wood fiber layer is arranged only on the front surface or on the front and back sides, and a wood chip layer is arranged on the back side of the front wood fiber layer or between the wood fiber layers on the front and back sides. Board. 2) Arranging a wood fiber layer made of wood fiber obtained by defibrating wood to which an adhesive has been added either only on the front side or on the front and back sides, and bonding between the wood fiber layer on the back side of the front wood fiber layer or between the front and back wood fiber layers. A method for manufacturing a composite board, which comprises laminating a layer of wood chips made of wood chips obtained by cutting wood to which a chemical has been added, and then pressing and bonding the layers to integrally form the layers. 3) A method for producing fiberboard, which comprises laminating wood fiber laminates on only the front surface or the front and back surfaces of a wood chip board using an adhesive, and then pressing them together to integrate them.