JPH0655364B2 - Method for manufacturing wood-based molded body - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention is a method for obtaining a wood-based molded product by supplying a wood-based molding material obtained by adding a binder or the like to wood fibers to a molding die and performing thermal compression molding. Regarding

(Prior Art) A so-called hard board is well known as a wood-based molded article, and is widely used for interior materials of automobiles, cabinets of electric products, and the like. However, this hardboard
A step of once forming a molding mat by adding a binder or the like to the wood fiber, and thereafter appropriately cutting this molding mat and thermocompressing the mat is adopted.
There is a problem that the process is complicated and the yield is lowered, and the moldability is poor, and it does not compete with the production of a molded product having a deep-drawn portion.

Therefore, a wood-based molding material in which a binder or the like is added to wood fibers is deposited on a perforated plate in a laminated container to form a material assembly, and then this material assembly is supplied to a molding die for thermocompression molding. A method has been proposed and has already been introduced in JP-A-62-90203 and JP-A-62-134215. According to this method, it is possible to solve most of the problems caused by the use of the molding mat, and to obtain a wood-based molded product that is low in cost and excellent in quality.

(Problems to be solved by the invention) By the way, according to the above-mentioned new manufacturing method, when the material aggregate is obtained, the bulk density of the material aggregate changes due to variations in the water content of the raw material chips, the defibration conditions, and the like. As a result, there is a possibility that the weight may vary and the subsequent compression moldability may be impaired. That is, when the weight is too heavy, the surface bulges due to an increase in the generated gas and the decrease in the air permeability of the substrate, and when the weight is too light, the strength becomes insufficient due to the decrease in the density.

To solve this problem, the inventors of the present invention, after forming the above-mentioned material aggregate, hold it in a laminated container and temporarily remove the upper surface thereof to measure the weight, and then measure the weight. As described above, a second manufacturing method was adopted, and after that, a manufacturing method was established in which the material was supplied to a molding die.
It was disclosed in No. 4. According to this method, a material aggregate having a constant weight can always be obtained, so that it is possible to obtain a wood-based molded product that is free from defects such as surface swelling and is more stable in strength.

By the way, according to the measures for deleting the surface of the material aggregate, it is necessary to remove the surface while holding it in the laminated container.
The removal range of the first time, that is, the weight adjustment range is limited to the distance between the upper end of the laminated container and the level of the first deletion, so that if the material assembly protrudes from the laminated container, it may exceed the allowable range. In this case, the desired amount of deletion cannot be obtained, and accurate weight adjustment becomes impossible. However,
As described above, changes in the bulk density of the raw material aggregate cannot be avoided due to variations in the water content of the raw material chips and defibration conditions, etc.
When viewed over a long period of time such as summer and winter, the bulk density often becomes too large or too small, and the projection margin exceeds the allowable range, and there is a risk that the actual weight adjustment will have to be abandoned. was there.

The present invention has been made in view of the above-mentioned conventional problems, and enables the control of the bulk density of the raw material aggregate, and thus allows the weight of the raw material aggregate to be subjected to thermocompression molding to be adjusted to a desired value. An object of the present invention is to provide a method for producing a molded article.

(Means for Solving the Problems) In order to solve the above problems, the present invention forms a material aggregate by depositing a wood-based molding material obtained by adding a binder or the like to wood fibers on a perforated plate in a laminated container. Then, while holding it in the above-mentioned laminated container, the upper surface of the material assembly is smoothly removed and the weight is measured, and then the second time is removed so that the predetermined weight is obtained, and then the material is supplied to the forming die. In the method for producing a wood-based molded body that is subjected to heat compression molding, when a molding material is deposited on the perforated plate of the laminated container, the suction air speed of the air sucked from the back part of the perforated plate of the laminated container is adjusted to set the material set. The gist is that it is configured to control the bulk density of the body.

In the present invention, in order to deposit the forming material on the perforated plate of the laminated container, a spray container is placed on the laminated container, and the forming material is floated down from the upper part of the spray container. At this time, the amount of the molding material deposited on the perforated plate is monitored by a sensor, and when the height reaches a certain level, the supply of the molding material is stopped. Further, an exhaust means is connected to the laminated container so that air can be sucked and discharged from the back of the perforated plate. And, for example, by inserting a damper in the piping system of the exhaust means, and adjusting the angle of this damper,
The suction wind speed of the air discharged from the laminated container is adjusted.

(Operation) In the method for manufacturing a wood-based molded product having the above-described structure, the bulk density of the material aggregate can be controlled within a predetermined range by adjusting the suction air velocity of air from the laminated container. The amount of protrusion of the aggregate from the laminated container can be kept within an allowable range, and the weight adjustment can be smoothly performed later.

(Example) Hereinafter, an example of the present invention is described based on an accompanying drawing.

In this example, wood fibers obtained by defibrating wood chips were added with a binder such as coumarone resin and phenol resin, and a water-repellent agent and an internal release agent were added to form a wood-based molding material. After being manufactured, this molding material is subjected to each molding step shown in FIG.

In the molding step, the molding material M is first supplied to the hopper 2 of the collecting apparatus 1 which constitutes the stacking step, and then is sprayed into the spray container 3 and the stack container 4 arranged under the hopper 2. A perforated plate 5 made of punching metal or the like is arranged below the laminated container 4, and the scattered forming material M is deposited on the perforated plate 5. Exhaust means, which will be described later, is also connected to the laminated container 4, and an air flow that passes downward through the perforated plate 5 is formed in the spray container 3 and the laminated container 4. The forming material floats and descends according to the flow of the air, and is sequentially deposited on the porous plate 5. At this time, the amount of the forming material M deposited on the porous plate 5 is monitored by a sensor (not shown), The supply of the forming material M is stopped when the height reaches a certain level, whereby the material aggregate w having a predetermined shape can be obtained. At the time of spraying the molding material M, a guide plate such as a traverser is provided in the spraying container 3, and the guide material is swung to scatter the molding material M in a wide range to uniformly deposit it on the perforated plate 5. To do so.

The laminated container 4 and the spray container 3 are detachable, and then the stacked container 4 is separated from the spray container 3 and conveyed to a shaving step described later to adjust the weight of the material aggregate w. The material aggregate w is transferred to the holder 6 by being conveyed to the transfer step. The retainer 6 has a porous plate 7 similar to the one described above inside, and the inside thereof can be exhausted by an exhaust means (not shown).
Are suction-held on the perforated plate 7 of the holder 6. afterwards,
The holder 6 moves to the forming device 8, releases its suction, and puts the material aggregate w into the mold. The molding die constituting the molding device 8 is composed of a lower die 9, an upper die 10 and a holding frame 11, and is heated to a predetermined temperature in advance. The raw material aggregate w put into the mold is compressed by the lowering of the upper mold 10, whereby a high-quality compact P can be obtained.

Details of the laminating step and the shaving step are shown in FIG. In the figure, reference numeral 12 is a carrying table for carrying the laminated container 4, in which a conveyor (not shown) is incorporated. An exhaust pipe 13 for exhausting the inside of the laminated container 4 is arranged below the transport table 12 at a site where the collecting apparatus 1 is installed. One end of the exhaust pipe 13 is connected to a suction fan (not shown), and the spray container 3 and the laminated container 4 are sucked and exhausted by the operation of the suction fan. The wind speed of the sucked air is adjusted by a damper 14 installed in the middle of the exhaust pipe 13, and this wind speed is constantly monitored by a wind speed sensor 15 also installed in the air distribution pipe 13. A shutter 17 that can be opened and closed by a cylinder 16 is provided on one side of the spray container 3, and the shutter 17 is opened when the deposition of the molding material M on the perforated plate 5 is completed, and the material aggregate is opened. w is conveyed to the shaving process together with the laminated container 4.

On the other hand, in the shaving step, the first rotary blade 18 is provided adjacent to the collecting device 1, and the second rotary blade 19 is arranged at a predetermined distance from the first rotary blade in the flow direction of the laminated container 4. Each is arranged. First and second rotary blades 18,19
Has a length capable of covering the entire laminated container 4 and is entirely covered with the hoods 20,20. Each hood 20 is connected to a main duct 22 via sub-ducts 21, 21, and the main duct 22 is connected to an exhaust means (not shown). The position of the first rotary vane 18 is fixed, and the upper surface of the material assembly on the laminated container 4 can be removed smoothly, while the position of the second rotary vane 19 moves vertically. It becomes movable and the upper surface of the material aggregate w can be deleted to an arbitrary depth. That is, while the material aggregate w moves on the transport table 12 together with the laminated container 4, the upper surface thereof undergoes the first shaving by the first rotary blade 18, and then the second rotary blade 19 performs the second shaving. It is supposed to be shaving. The molding material removed by the rotary blades 18 and 19 is returned to the original state via the sub duct 21 and the main duct 22.

In the shaving process, a weighing device 23 is arranged below the transport table 12 and in a portion located between the first and second rotary blades 18 and 19. The weighing device 23 includes a weight sensor on a table 25 that can be moved up and down by a cylinder 24.
26, and the stacked container 4 is placed on the weight sensor 26 by raising the table 25 by operating the cylinder 24.
It is possible to place the lower frame 4a of the above and measure the total weight of the laminated container 4 including the material aggregate w. Then, based on the weight measured by the weighing device 23, the deletion amount (deletion height) of the second shaving described later is determined, and the second rotary blade 19 moves to a height at which the deletion amount can be obtained. Shaving is performed so that the material aggregate w has a constant weight.

Here, the material aggregate w after the removal with the first rotary blade 18
Is H ₁ (constant), the height of the material aggregate after being deleted by the second rotary blade 19 is H ₂ , and the weight of the material aggregate w after being deleted by the first rotary blade 18 is If the weight (set weight) of the material aggregate after being deleted by W ₁ and the second rotary blade 19 is W ₂ , the amount of deletion (delete height) by the second rotary blade 19 ΔH
Is given by the following equation (1).

ΔH = H ₁ −H ₂ = H ₁ (W ₁ −W ₂ ) / W ₁ (1) By the way, the material aggregate w after the first shaving described above.
When the bulk density ρ and the area of the laminated container 4 are S (constant), the weight W ₁ of the above is given by the following (2) also using the above H ₁ .

W ₁ = ρSH ₁ (2) That is, the weight W ₁ of the material aggregate w after the first shaving is greatly influenced by the bulk density ρ. However, as described above, the bulk density ρ of the lever largely changes due to variations in the water content of the raw material chips, the defibration conditions, etc. Over, you may come out of weight,
On the other hand, if the bulk density ρ is too large, the amount of deletion ΔH required for the second shaving becomes large, and the material aggregate w
Since the upper surface of the above is positioned inside the laminated container 4, it becomes impossible to delete the desired deletion amount ΔH.

Therefore, in this embodiment, when the molding material M is deposited on the perforated plate 5 of the laminated container 4 in the laminating step, the damper 14 is used.
By adjusting the angle of
The bulk density ρ of the material aggregate w is kept within a certain range. According to the experiment, H ₁ = 12.2 cm, S = 5390 cm 2,
When the inner diameter D of the exhaust pipe 13 is set to 280 mm, the bulk density ρ of the material aggregate w after the first shaving, that is, the weight W ₁ changes linearly with respect to the suction wind speed as shown in FIG. I knew what to do. In this case, the range in which the weight can be adjusted without hindrance by the second shaving is about 2.
It is in the range L of 1 to 2.55, and therefore this allowable range L
Suction wind speed or tamper 14 so that the bulk density ρ subsides
If the angle of is adjusted, the weight can be accurately adjusted even if the water content of the raw material chips and the defibration conditions change.

By the way, in the long term for four months, when the suction wind speed is fixed at 11 m / s, as shown in FIG. 3, the bulk density ρ of the material aggregate w exceeds the permissible range L, and as a result, the weight A situation occurs in which adjustment is impossible.

(Effects of the Invention) As described above in detail, according to the method for manufacturing a wood-based molded body according to the present invention, the bulk of the material aggregate is adjusted by adjusting the suction wind speed of air from the laminated container. Since the density is controlled within a predetermined range, the amount of protrusion of the material aggregate from the laminated container can be kept within an allowable range, and there is an effect that weight adjustment can be smoothly performed later. Since the weight can be adjusted, the variation in the properties of the wood fiber in the previous step can be allowed, and the material management can be facilitated by that amount and the manufacturability can be improved.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a laminating step and a shaving step, which are part of the manufacturing process of a wood-based molded body according to the present invention, and FIG. 2 is a relationship between the bulk density of the material aggregate and the suction wind speed. FIG. 3, FIG. 3 is a correlation diagram similar to FIG. 2 showing an example of a problem in the case of not according to the present invention, and FIG. 4 is a schematic diagram showing a molding process of the wood-based molded body. 1 ... Collecting device, 4 ... Laminated container 5 ... Perforated plate, 6 ... Retainer 13 ... Exhaust pipe, 14 ... Damper 15 ... Wind speed sensor, 18, 19 ... Rotating blade 23 ... Weighing device, M ... Molding material w ... Material assembly body

Claims (1)

[Claims] Claims: 1. A wood-based molding material comprising a wood fiber and a binder added thereto is deposited on a perforated plate in a laminated container to form a material assembly, which is then held in the laminated container. In the method for producing a wood-based molded product, the upper surface of the is removed smoothly and the weight is measured, and then the second removal is performed so as to have a predetermined weight, and then the product is supplied to a molding die and subjected to thermocompression molding. A method for manufacturing a wood-based molded product, which comprises controlling a bulk density of the material aggregate by adjusting a suction wind speed of air sucked from a back portion of the perforated plate when depositing a molding material in the laminated container.