JPH0775880B2 - Composite material and manufacturing method thereof - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a composite material and a method for producing the same, and more particularly to a composite material in which a metal coating layer is formed on a wood fiber board and a method for producing the same.

<Prior Art> Japanese Patent Laid-Open No. 50-12948 discloses a hardboard, plywood, wood,
The surface of the substrate board such as slate, ceramics, etc. is sprayed with a metal or alloy having a melting point of 900 ° C or less, and then 1000 or more
Disclosed is a heat-resistant board sprayed with a metal or alloy having a melting point of ˜1600 ° C. The board according to this conventional technique is one in which two layers are sprayed, and is excellent in heat resistance and water resistance.

<Problems to be Solved by the Invention> Since the heat resistant board according to the above-mentioned conventional technology is a composite of a base material and a metal layer, the difference in expansion and contraction due to moisture absorption, water absorption, drying and heat in the base material and the metal layer. As a result, the board itself tends to be warped, twisted, cracked, or delaminated between the substrate and the metal layer. Especially hardboards,
Organic base materials such as plywood and wood have a greater degree of moisture proofing, waterproofing, expansion and contraction associated with drying than inorganic base materials, and the above tendency tends to occur when such an organic base material and a metal layer are combined. Remarkably appears. Therefore, the heat-resistant board according to this conventional technique has not been used as a building material, furniture, or building member under the present circumstances.

<Means for Solving the Problems> The present invention has been completed after intensive efforts to solve the problems in view of the drawbacks of the conventional techniques, and is present in fibers. A composite material comprising a substrate made of a wood fiber board that has been acetylated to replace hydroxyl groups with acetyl groups, and a metal coating layer formed by a thermal spraying method on at least one surface of the substrate.

The present invention also provides a method for producing such a composite material, which comprises degreasing and softening wood chips by vapor deposition and then defibrating them to obtain wood fibers, which are then mixed with acetic anhydride. The wood fiber mat is formed by heat-reacting while immersing the wood fiber in the reaction solution to replace the hydroxyl group in the wood fiber with an acetyl group, and molding and integrating the acetylated wood fiber with an adhesive substance. The wood fiber mat is thermoformed to form a wood fiber board, and a metal coating layer is formed by spraying a metal on at least one surface of the wood fiber board and then cooling.

Wood fibers used in the present invention, for example, pine, cedar, softwood materials such as cypress or rawan, capoule, chestnut, after making hardwood materials such as poplar into chips, degreasing and softening treatment by steaming the chips, Further, it is obtained by defibrating the steamed chips with a defibrating device. Most of these wood fibers have a length of 1 to 30 mm and a diameter of about 2 to 300 μm. This wood fiber is shaped like bundles of conduits and temporary conduits, or cells are bundled, and the cell walls around the fibers are often torn or cracked, so they absorb moisture and water well. To do.

The obtained wood fiber is dried by a dryer and then acetylated to replace the hydroxyl groups present in the wood fiber with acetyl groups. In this acetylation treatment, wood fiber is impregnated with or without a catalyst as an aqueous solution of a metal acetate such as sodium acetate or potassium acetate and dried, and then the reaction with acetic anhydride such as acetic anhydride or chloroacetic anhydride is carried out. It is carried out by immersing in a liquid bath and heating at 100 to 150 ° C. for several minutes to hours. After completion of the reaction, excess reaction liquid is removed, washed and dried.

The acetylated wood fiber is put into the mixing device,
Adhesives, sizing agents, etc. are added and mixed to adhere. Then, the wood fibers are blown, and a forming machine forms a continuous wood fiber mat having a constant thickness on the conveying device.

The obtained wood fiber mat is cut to a predetermined length, then inserted into a hot press and thermocompressed to obtain a wood fiber board. The specific gravity of this wood fiber board is preferably within the range of 0.4 to 1.2. The reason is that when the specific gravity is 0.4 or less, the surface is porous and the metal coating layer is difficult to be formed, and it is necessary to increase the film thickness.
This is because if it is above, the surface becomes too dense, the anchoring effect on the wood fiberboard of the metal coating layer decreases, and the adhesive force decreases. The water content of the wood fiber board is preferably 20% or less. The reason for this is that if the water content is 20% or more,
During metal spraying, the heat causes the internal water on the sprayed surface to evaporate and move water to the opposite side, causing an imbalance in the internal balance and causing a warp in the wood fiberboard itself that is concave on the sprayed surface during metal spraying. This is because it becomes easier.

The obtained wood fiber board is cured and, if necessary, its surface (the side on which the metal coating layer is to be formed later) is sanded, and then a necessary amount of molten metal is sprayed using a thermal sprayer to perform thermal spraying. The metal spraying can be performed not only on the front surface of the wood fiber board, but also on the back surface, the required area such as the mouth end surface, or the entire surface. The temperature of the surface of the wood fiberboard where metal spraying is performed is 40
It is preferably -100 ~ 100 ℃, from this viewpoint, while the temperature of the wood fiberboard after thermocompression molding is high, or at least after warming the temperature of the surface of the wood fiberboard forming the metal coating layer, the metal It is preferable to perform thermal spraying. If the temperature is 40 ° C. or lower, the sprayed molten metal will be immediately cooled and solidified, so that the adhesion force due to the anchoring effect on the coated surface of the wood fiber board will not be sufficiently exerted. Further, when the temperature is 100 ° C. or higher, the influence of the temperature of the molten metal is strong and the surface of the wood fiber board is deteriorated, so that the adhesion is lowered. As the metal to be sprayed, metal alloys such as tin, lead, zinc, copper, brass, bronze, aluminum, nickel, iron and stainless steel are preferably used. As the thermal spraying method, a generally used electric wire spraying method,
Either the gas spraying method or the powder spraying method may be adopted. The sprayed metal solidifies by subsequent cooling,
A metal coating layer is closely formed on the surface of the wood fiberboard.

<Function> The heat resistance is improved by the metal coating layer formed on the surface of the wood fiberboard. The wood fiberboard has excellent dimensional stability because the hydroxyl groups in the wood fiber are replaced with acetyl groups and is acetylated, and the expansion and contraction of the board due to moisture absorption in the wood fiber and drying are suppressed. . In the wood fiber board itself, since the wood fiber is subjected to the steam degreasing treatment, it is not necessary to carry out the pretreatment when the molten metal is sprayed.

<Example> A chip of radiata pine is 160 by a digester.
It was degreased and softened by steaming at 7 ° C / cm ² for 5 minutes. The chips were defibrated with a defibrillator refiner to obtain defatted wood fibers. After this wood fiber was dried, it was immersed in acetic anhydride and heated and reacted at 120 ° C. for 1 hour. After completion of the reaction, excess reaction liquid was removed, immediately put into a washing machine, washed with water, and dried to obtain an acetylated wood fiber. At this time, the weight increase rate due to acetylation was 17%.

The acetylated wood fiber was put into a blender, and 4% of wax size and 10% of phenol resin adhesive was added and mixed with respect to the amount of wood fiber in the blender, followed by air blowing and screening with a felter. Formed on a conveyor to form a continuous wood fiber mat of constant thickness. This wood fiber mat is cut into widths and lengths, then inserted into a hot press and press-molded at 200 ° C for 4 minutes to obtain a specific gravity of 0.8, 10mm thick, 3'x6 'size wood fibers. I got a plate.

The obtained wood fiber board was cured, and when the surface temperature reached 50 ° C, a nickel alloy (Ni30%, Z
n4%, Cu66%, melting point 800 ~ 1200 ℃)
After cooling, a metal coating layer was formed and a composite material according to the present invention was obtained.

<Effects of the Invention> The composite material according to the present invention is excellent in heat resistance and water resistance due to the formation of the metal coating layer on the surface of the wood fiberboard, and the substrate fiberboard which is the base material is acetylated. Therefore, the dimensional stability is excellent, and expansion and contraction due to moisture absorption and water absorption are suppressed. Therefore, it is widely used as a building material or furniture / building member.

Claims (3)

[Claims] 1. A substrate is a wood fiber board that has been acetylated to replace the hydroxyl groups present in the fibers with acetyl groups.
A composite material comprising a metal coating layer formed by a thermal spraying method on at least one surface of the substrate. 2. Wood chips are degreased and softened by steaming and then defibrated to obtain wood fibers. The wood fibers are soaked in an acetic anhydride reaction solution and reacted by heating to remove hydroxyl groups in the wood fibers. The acetyl group is substituted, and thus the acetylated wood fibers are molded and integrated with an adhesive substance to form a wood fiber mat, and the wood fiber mat is thermocompressed to form a wood fiber board. A method for producing a composite material, comprising forming a metal coating layer by spraying a metal on at least one surface of a wood fiber board and then cooling the metal. 3. The method for producing a composite material according to claim 2, wherein the metal spraying is performed in a state where the material temperature of the wood fiberboard after thermocompression molding is 40 to 100 ° C.