JP2003251615A - Woody compound material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a woody compound material capable of being sufficiently used as a structural material even if short woody material piece of <15 cm to be obtained by crushing the volume reduction treatment of a woody waste is used. <P>SOLUTION: For the woody compound material to be obtained by heating, pressurizing and molding a woody mat which comprises an intimate mixture of a slender woody material piece and a bonding agent and is formed by stacking the slender woody material piece being oriented in one direction, the woody compound material is provided by occupying 50 to 70% of a sectional area by the slender woody material piece of <5 mm in thickness on a vertical longitudinal section in an orientating direction of the woody material piece. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wood-based composite material composed of a mixture of elongated wood material pieces and a binder.

[0002]

2. Description of the Related Art A wood-based material, for example, a wood-based structural material or a wood-based material piece obtained by laminating a mixture of an elongated wood-based material piece and a binder in the longitudinal direction, stacking them, and pressing and heating the wood-based material There is known a wood-based structural material obtained by laminating a system material in the length direction, forming a mat-shaped material, and pressing and heating the material (registered patent No. 2527761).

Among the synthetic wood-based composite materials produced in this manner, those for structural materials are generally wood materials having a fiber direction length of 15 cm or more in order to obtain necessary and sufficient strength. One piece is used (for example, Japanese Examined Patent Publication No. 50-
17512).

On the other hand, in recent years, various studies have been made on the effective use of wood waste from the viewpoint of recycling. However, when wood waste is used as a raw material, it is difficult to obtain a woody material piece having a fiber direction length of 15 cm or more, and it is difficult to obtain a woody composite material that requires structural strength. That is, wood waste includes scrap materials generated at factories and residential construction sites, waste pallet materials discarded after transporting members, dismantling waste materials generated during building demolition, etc., but these are all dry, Moreover, since foreign matter is mixed in, a cutting blade is easily damaged and stable operation is difficult.

[0005]

The object of the present invention is to omit the problems in the construction of the above-mentioned conventional wood-based structural materials, and to obtain a short product of less than 15 cm obtained by crushing and reducing the volume of wood-based waste. An object of the present invention is to provide a wood-based composite material that can be sufficiently used as a structural material even if a wood-based material piece is used.

[0006]

DISCLOSURE OF THE INVENTION The present invention comprises a mixture of an elongated wooden piece and a binder, and the elongated wooden piece is laminated in one direction to form a wooden mat, A wood-based composite material obtained by heating and pressing the wood-based mat, the elongated wood material having a thickness of less than 5 mm in a vertical cross section perpendicular to the orientation direction of the wood-based material pieces in the wood-based composite material. 50 pieces of cross section
It is a wood-based composite material characterized by occupying ~ 70%.

Examples of tree species of the woody material include conifers such as cedar, cypress, pine, spruce, and fir, and broad-leaved trees such as birch, apiton, sengonlaut, and aspen. Materials can also be included.

[0008] Examples of usable forms include logs of the above tree species, raw materials such as thinned wood, etc., but from the viewpoint of recyclability, scrap materials generated at factories and residential construction sites, scrap materials after transportation, are discarded. Examples include waste pallet materials and dismantled waste materials generated during construction demolition. In particular, demolition waste materials,
It is more preferable to use wood materials such as waste pallet materials, thinning materials, and scrap materials generated during lumber that are currently discarded or used as fuel or raw materials for papermaking.

As a method of processing the above-mentioned raw material into a slender wood material piece, a hammer mill, a uniaxial crusher for crushing wood by rotating a roll having a knife on the surface, a biaxial or multi-axial structure in which rotary blades are engaged You can use a shredder such as a shaft shredder, but you can also use a rotary cutter that cuts veneered products into sticks by cutting them into sticks, a flaker that cuts logs with a rotary blade into strands, and so on. Among them, the crusher is preferable because the rotary blade is easily damaged due to foreign matter when a recycled material is used as a raw material.

Since the slender wood material pieces obtained by the above method vary in size, a wood material piece of a predetermined size is obtained by the classification process. As the classification method at this time,
There are a roller screen method, a vibrating mesh method, a wind selection method, etc., which can be used as needed.

In the wood-based composite material of the present invention, in a vertical cross section perpendicular to the orientation direction of the wood material pieces, elongated wood material pieces having a thickness of less than 5 mm occupy 50 to 70% of the cross-sectional area. Characterize. When the thickness of the wood material piece of less than 5 mm is less than 50% of the cross-sectional area, it is difficult to secure a sufficient physical property as a structural member due to a structure in which a good laminated state is not formed in a laminated state and there are many gaps Become. Also, 70% of the cross-sectional area
When it exceeds the above, it becomes difficult to orient the wood material piece in one direction in the laminating process, and in this case as well, it may not be possible to satisfy the physical properties sufficient as a structural member, and much energy is required to crush the raw material. Is consumed.

It is preferable that the classified elongated wood material pieces have a water content adjusted within a certain range. By keeping the water content constant, there is no variation in the quality of molded products during production. The preferable water content is 0 to 15% by weight.

Examples of the binder include phenol resins, urea resins, isocyanates, and other adhesives for the wood industry used for plywood and particle boards. These binders may be used alone or in combination of several kinds. Good.
The amount of the binder mixed depends on the density, shape and surface condition of the wood material piece, but is usually 1 to 2 with respect to the weight of the wood material piece.
0 wt% is desirable.

Examples of the method for mixing the wood material pieces and the binder include a method in which the wood material pieces and the binder are put into a mixer such as a Henschel mixer and mixed, and the wood material is used on a conveyor or in a drum blender. By using an application means such as spraying the binder to the material pieces, the binder can be easily attached uniformly on the surface of the wood material piece, and a structural material having stable strength can be easily obtained after molding.

The mixture of the wood material pieces and the binder is laminated while being oriented in a predetermined direction. The mat can be produced by putting pieces of wood material into a mold and stacking them. In order to orient in one direction, it is put into a forming die divided at regular intervals, or an orientation laminating apparatus such as a disc orienter used in a manufacturing apparatus for existing wood-based molding materials such as oriented strand board (OSB). Can be used.

As a heating and pressure molding method, after the above mat is formed, it is put into a press device capable of pressurizing and heating and pressurizing and heating. Examples of the pressing device include a method of transferring heat from the surface of the wood material piece to the inside by heat transfer such as a hot plate, and a method of directly heating the inside such as steam injection and high frequency heating.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Samples were molded by the following manufacturing process. Elongated wood material pieces (hereinafter referred to as "chips") have a chip thickness of 5 mm using a web roller screen device (manufactured by Taihei Co.) of board chips (crushed by a uniaxial shredder) purchased from a wood waste disposal company. Less than 5-11
mm and over 11 mm, respectively. By the way, the weight ratio is 55%, 32%, 13%,
Among the above chips, the maximum chip length classified to 11 mm or less was 90 mm.

The above chips were adjusted to a water content of 6% by weight, a predetermined amount of classified chips was placed in a drum blender, and an isocyanate adhesive as a binder was spray-coated at 5% by weight on the chips. Next, the chip coated with the binder is put into an OSL forming machine (manufactured by Taihei Co., Ltd.), and a forming die (vertical 2000 mm, horizontal 500).
mm, height 100 mm). The inside of the forming mold is 50 mm using a metal partition plate (thickness: 2 mm)
Using a material divided into 10 equal intervals, the layers were oriented and laminated in one direction.

Next, the forming mold and the partition plate were removed, and the mat was pressed with a press machine (heat transfer type, manufactured by Kawasaki Yuko Co., Ltd., 3
00t press pressure). The die of the pressing machine has a length of 2500 mm, a width of 500 mm, and a height of 150 mm. The mixture was heated and pressurized at a heating temperature of 180 ° C. and 3 MPa for 10 minutes so that the final shape of the molded product would be 2000 × 500 × 30 mm.

(Example) Of the chips crushed and classified by the above web roller screen device, 63% by weight of chips having a thickness of less than 5 mm and 37% by weight of chips having a thickness of 5 to 11 mm.
A wood-based composite material was obtained by using the above method.

(Comparative Example) A wood-based composite material was obtained in the same manner as in the Example by using only 100% of chips having a thickness of 5 to 11 mm.

(Chip distribution in cross-sectional area) In the wood-based composite material obtained by the above method, a vertical cross section perpendicular to the orientation direction of the elongated wood material pieces is subjected to image processing to obtain wood material pieces (chips).
As a result of statistically processing the distribution for each thickness, the sample of the example has a chip thickness of less than 5 mm of 63% and 5 mm or more of 37%
The cross-sectional composition ratio was On the other hand, the comparative sample is
Chip thickness less than 5 mm 0%, chip thickness 5 mm or more 10
It had a sectional composition ratio of 0%.

The density, flexural strength, flexural modulus, and rate of water absorption dimensional change in the pressing direction during molding are determined according to JIS.
It measured based on Z2101.

Water absorption dimensional change rate = (dimension in a state where a constant weight is obtained at 23 ° C. and 50% RH after being immersed in 23 ° C. water for 24 hours) / (before water immersion, 23 ° C. and 50% RH) The dimension when the weight is constant) x 100

[0025]

[Table 1]

As can be seen from the results shown in Table 1, the samples of Examples are excellent in bending strength, bending elastic modulus and water absorption.

EFFECTS OF THE INVENTION The wood-based composite material of the present invention uses wood material pieces having different thicknesses unlike conventional wood material moldings. Therefore, in the state of a laminated mat, a small wood material is provided in a gap between large wood material pieces. A piece of material enters and becomes a filled state with few voids. As a result, the molded product obtained by pressurizing and heating has a weakness in strength and few voids that serve as water passages, so that the mechanical strength is high and the dimensional change in water absorption is low.

Claims (2)

[Claims] 1. A wood-based mat is formed by laminating a mixture of an elongated wooden material piece and a binder, and the elongated wooden material pieces are laminated while being oriented in one direction to form a wood-based mat. A wood-based composite material obtained by pressure molding, wherein a long and narrow wood material piece having a thickness of less than 5 mm has a cross-sectional area in a vertical section perpendicular to the orientation direction of the wood material piece in the wood-based composite material. A wood-based composite material characterized by occupying 50 to 70%. 2. The wood-based composite material according to claim 1, wherein the elongated wood material pieces are made of recycled wood.