JPS63502910A - Method and apparatus for forming hardened wood fiberboard, preferably by curving - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Method and apparatus for forming sanded wood fiberboard, preferably by curving The present invention is a hardened flat wood fiber made of cellulose fiber, lignin and hydrogenated oil. Preferably, the fiberboard is bent by wetting, heating, bending and subsequent cooling. It is related to the method of molding.

Short and brittle cellulose fibers, intermediate lignin, and so-called hydrogen bond bridging Hardened wood fibre, consisting of a small amount of hydrogenated oil, which is a drying oil that has the function of forming bonds. Barboard can be produced in principle in two different ways: at high temperature in combination with moisture or Can be bent using low temperatures.

When using the high temperature method, the fiberboard is heated to approximately 165℃ during the manufacturing process. Usually, it is hardened. When the temperature rises a few places above 165°C, the board loses oxygen. spontaneously combusts in the presence of In that case, the fiber is overcured and the hydrogen bonds are It breaks down and a carbonization process begins, resulting in a rapid loss of board strength. subordinate So, if you want to soften lignin at about 200℃ in order to bend the board, oxygen preferably in the presence of high pressure steam to reform the hydrogen bonds. The softening process must proceed in an autoclave. the board is completely It cannot be bent until heated. Therefore, quick bending can be achieved using known heating methods. Extremely hot contact play is required to ensure that moisture remains in the board. It is necessary to However, if you try to leave moisture inside the board, the heat will be at the center of the board. The heat from the contact plate destroys the fibers on the surface.

When heated in the absence of moisture or oxygen, hydrogen gas or A complex and expensive process with continuous supply of other inert gases is required.

When using a low-temperature method, if high-frequency heating is used, the temperature can be reduced to approximately 40-70℃. Despite being at a relatively low stage, the board softens after about 8 seconds and softens further by about 100%. ℃, it can be bent into a desired shape with a very small radius of curvature.

However, this process does not proceed at all in the presence of moisture. As soon as the curved zone dries, it becomes hard and brittle and cannot be bent further. becomes impossible. Therefore, the bending process depends on the temperature of the board, the moisture content in the bending zone. rate, the amount of energy supplied during the bending process, the amount of moisture remaining on the board, and It depends on the board bending speed while passing through the bending machine. Both of these factors is independent. For example, if the board temperature is too low or too hard, the high-frequency heating electrode is torn off or the board is torn. If the moisture content is too low, it will be fed Continuous bending process is difficult due to rapid reduction of radio frequency energy and excessively low temperature. The board may be too stiff, causing the board to continue to energize as it passes through the equipment. The poles will tear off or the board itself will be damaged.

The purpose of the present invention is to solve the above-mentioned disadvantages and to produce a wood fiber board like a headboard. The object of the present invention is to achieve a continuous method and apparatus for controlling the bending of the curve. Inventor Features of the method and apparatus will become apparent from the claims below.

In the present invention, the moisture content in the board required to allow the board to bend is It can be obtained very quickly using chemical solutions. When using pure water Penetration can be increased approximately 100 times compared to In this way, the curved Zo Since the moisture content of the fibers is increased, sufficient moisture is maintained throughout the bending process while heating. It is possible to maintain the high frequency energy and concentrate the supplied high frequency energy at the same time.

This allows boards to be sent to the equipment at high speeds such as 10-15 m/gain. A continuous bending process is possible.

The invention will be described in detail below with reference to the accompanying drawings.

Figure 1 is a plan view schematically showing a device for continuously curving hardened wood fiberboard. , FIG. 2 is an enlarged perspective view schematically showing two opposing forming surfaces of the thermoforming device; 3 is a side view of the apparatus schematically shown in FIG. 1; FIG.

As is clear from the drawings, the flat shape to be formed preferably by curving Fiberboard 1 consists of cellulose fibers, lignin and hydrogenated oil. It is fed into the molding device from the right side by feeding N9. The device continuously sends board 1 (both include one conveyor 2. A feeding device 9 located at the starting point of the conveyor 2) At the rear of the board, particles are removed from the board 1 in progress, the board surface is roughened, and the board is Brush means 7 are provided to remove the wax material and facilitate wet processing. need After passing through the preheating device 6, the board enters the wetting device 3 and is bent Wet the desired board zone with a chemical solution. In that case, the chemical solution is It is applied to the top and/or bottom surface of the board 1 by any suitable means such as syspray.

In addition to water, this solution contains a surfactant and an alkali salt. As a surfactant is an alkyl sulfate type, and the alkali salt is a sodium hydroxide type. It is preferable to use On the downstream side of the wetting device 3 there are 2 which act as electrodes. A heating forming device 4 having two forming surfaces 8 is provided, and a board is inserted between the forming surfaces 8. 1 passes through and is heated and bent at the same time. A pair of forming surfaces 8 are schematically shown in FIG. It is arranged along one or both sides of the conveyor 2 in the direction of movement of the board 1 as shown in FIG. ing. There is a cooling device 5 downstream of the thermoforming device 4, and the board is placed in the cooling device. It is cooled and its shape is fixed at the same time. The molding surface 8 of thermoformed E4 has low friction. It should be properly coated with a low dielectric loss plastic material, such as Teflon (trade name). Ru.

The method of the present invention for bending hardened wood fiberboard is carried out in the manner described below. be done. Slide board 1 one after the other, preferably with no spacing between the edges, to the right as shown. The brush is sent to the left, and while being conveyed by the conveyor 2, it is first delivered to the brushing device 7. , where the board is brushed through its curved zones. Then board 1 It enters the preheating device 6 and is heated to about 30-90°C, preferably 60-80°C.

During the movement, the board is placed in the wetting device 3 on the top surface of its zone to be curved and/or The bottom surface is wetted with a chemical solution before entering the thermoforming device 4 where it is preferably In other words, it is high-frequency heated to about 40-160℃ at 27MHz, and at the same time it is shaped into the desired shape. curved or formed. The board is cooled in the cooling device 5, and its curved shape The condition is fixed. Once the above steps are completed, the board is stored or transported to the location where it will be used. do it.

For chemical additives to water, include alkyl sulfates and sodium hydroxide This has several positive effects. For example, the conditions necessary for continuous processes Chemical solution penetration into the board is facilitated. Alkaline additives are cellulose Expanding the fiber, combined with the low surface tension provided by the alkyl sulfate, Enables quick water absorption action of lurose fiber. This formulation is also a sulfate quencher. Softening of the glue sulfonic acid in the board is achieved in the same way as in the case of softening. inside the board When the alkali is neutralized by acidic substances, the ligrin hardens again after the molding process. become Said formulation also has the effect of allowing concentration of six frequency energy. The present invention A board that has a chemical solution sufficiently penetrated into the curved zone will have an extremely high loss rate (1os sfactor). That is, high frequency energy is concentrated in the wet zone. loss The rate doubles and the dielectric constant increases. This means that the fibers in the wet zone of the board This means that the field is dense.

As already mentioned, when forming the board in the thermoforming device 4, the board is It is heated while continuously passing through a thermoforming device 4. The boards touch each other in the direction of movement. 2 which is fixed to the board and serves as an electrode that generates high frequency energy. The distance between the forming surfaces is set to the thickness of the board to be curved. It is.

As is clear from FIG. 2, the forming surface 8 forming the longitudinal gap in the conveying direction is In a preferred embodiment, in the thermoforming device 4 there are arranged on both sides of the conveyor 2, The side edges of the board form approximately a 90° angle with the main plane of the board. Curve upward or downward.

In the light of the test results, wetting the board by preheating it in the preheating device 6 If the curved zone is preheated before treatment, the aqueous solution penetrates the board approximately 8 times faster. Ru.

Additionally, this preheating process prevents the solution from spreading along the plane of the board. and can be concentrated to penetrate deeply into the curved zone.

Claims (8)

[Claims] 1. Hardened flat wood fiber consisting of cellulose fiber, lignin and hydrogenated oil - Preferably bending the board by wetting, heating, bending and subsequent cooling. This is a method of molding by continuously feeding the hoard into a heating device and moving it Apply a chemical solution to the top and/or bottom of the sawn that is to be curved. This results in a wetting process and then the board is exposed to high frequency energy, preferably at 27 MHz. Curve or shape it into the desired shape while heating it to about 40-160℃, and then cool it. A method characterized in that the intermediate board is maintained in said shape. 2. The board is heated to approximately 30-90°C, preferably 60-80°C, before feeding into the wetting equipment. 2. A method according to claim 1, characterized in that the preheating is performed to a temperature of . 3. Wet the board in a wetting device until its moisture content is approximately 12-17%. A method according to claim 1, characterized in that the method comprises: 4. The curvature or shaping of the zone to be curved of the board is preferably curved in the direction of travel. The board is fed between two molding surfaces that are sequentially fixed to the board with their edges in contact. Heating is carried out simultaneously and continuously on each sheet, and the forming surface is exposed to high frequency energy. The mutual spacing is set to the thickness of the board to be curved. A method according to claim 1, characterized in that the method comprises: 5. Claim 4, characterized in that the molding surfaces are biased toward each other by a spring. The method described in section. 6. Hardened flat wood fiber consisting of cellulose fiber, lignin and hydrogenated oil - Curving the board preferably by wetting, heating, bending and subsequent cooling. at least one device for continuously feeding the board (1); a conveyor (2) of a wetting device (for applying a predetermined amount of moisture to the top and/or bottom surface of the board (1); 3) and a board (1) having two molded surfaces that also serve as electrodes and passing through the molded surfaces. A heating forming device (4) that heats and shapes the board at the same time, and a device that fixes the board in that shape. An apparatus characterized in that it includes a cooling device (5). 7. The conveyor (2) includes a preheating device (6) before the wetting device (3), and the chemical solution The board can be preheated to about 30-90°C in the preheating device before coating. 7. The apparatus according to claim 6. 8. Characterized by coating the molding surface with an alast material with low friction and low dielectric loss. Apparatus according to claim 6.