JPH0620732B2 - Method for manufacturing wood-based molded body - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing an essentially molded article, and more particularly to a method for directly producing a compression molded article using a wood fiber to which a binder is added. .

[Conventional technology]

In general, a wood-based molded body is manufactured by compression-molding wood fibers, which are obtained by loosening wood or the like, by utilizing the bonding property of the wood fiber itself. This wood-based molded body is a so-called hard board, and the material is more uniform and lighter than plywood,
It has few defects, has a smooth surface, and is excellent in heat resistance, water resistance, and moisture resistance, and because it is strong relative to the plate thickness, it is an interior material for construction, furniture, interior base material for automobiles, It is widely used as a material for cabinets such as televisions and stereos.

As a method for producing this wood-based molded body, for example, wood chips are steamed and defibrated to form wood fibers, and the wood fibers are mixed with a synthetic resin and cellulose paper and dispersed in water, followed by pressure filtration and Wet molding method of pressing (so-called paper making) and heat compression molding of the obtained mat (soft fiber board), or adding binder such as synthetic resin to wood fiber obtained by steam disintegrating wood etc. Examples of the dry mat method include a method in which the molding mat is formed by mixing after mixing, hot rolling and forming the molding mat, and the molding mat is subjected to heat compression molding.

Using the dry mat method as an example,
This will be described in more detail.

First, put the wood chips in the steaming tank of the defibration machine,
After steaming with steam at 80 ℃ to soften the chips and make the fibers easy to peel off, supply them to the defibration disc,
The defibrating disc is used to loosen wood fibers. After the defibrated wood fiber is dried with hot air, a long fiber for improving deep drawability, for example, 17% hemp fiber and 7% polypropylene fiber, and a binder composed of a phenolic thermosetting resin, a thermoplastic resin, or the like. 8% and 1 to 5% of a water repellent such as rosin and paraffin are thoroughly mixed. next,
This wood fiber added with a binder and the like is deposited and hot roll pressed to form a mat M1 having a thickness of about 10 to 40 mm as shown in FIG.

Next, the molding mat M1 is cut into a shape slightly larger than the shape of the completed wood-based molded body and placed on the lower mold 2 of the compression mold 1 as shown in FIG. Then with the hot plate 6
The lower mold 2 and the upper mold 3 heated to 180 to 220 ° C. are brought together by lowering the upper mold 3. Then, gas is generated, so the mold is opened to remove the gas, and the upper and lower molds are aligned. In this way, the preliminary compression and the degassing are repeated several times, and then the upper mold 3 and the lower mold 2 compress as shown in FIG. At this time, the inside of the molding space is sucked through the gas vent hole 5 and the suction pipe 7 to release the generated gas. In the figure, 4 indicates a derivative material, and 8 indicates pulp. Next, the mold is opened and the product is taken out to obtain a wood-based molded product M2.

[Problems to be solved by the invention]

However, the above-described conventional method for manufacturing a wood-based molded product has the following problems.

In the dry mat method, in order to easily supply the wood fiber to the compression mold, a step of molding the wood fiber into a mat that is easy to handle and a step of cutting the mat into a predetermined shape are required, and many manufacturing steps are required. In addition to being complicated, a binder such as a thermoplastic resin is necessary for matting the wood fiber. Also, when the mat is compression molded, the mat is caught by the squeezing part,
It is necessary to cut the mat a little larger than the completed molded body, and there is a problem that cutting scraps, derivative materials cut off during molding, etc. are wasted, yield is poor, and production cost rises. Further, in the case of producing a molded product having a deep-drawn part, in order to improve the deep-drawn rawness of the mat, in addition to wood fiber as a mat material, long fibers such as hemp and thermoplastic resin ropes, which have high raw material costs, etc. It is necessary to add a binder such as a thermosetting resin in the case of using hemp fiber having no adhesive growth, and there is also a problem that the cost becomes high in these respects.

Further, in the case of producing a molded body having a deep-drawn portion, when the mat contains a large amount of wood fibers, the mat must be pre-formed into the shape of the molded body by softening the mat with steam in order to improve the deep-drawing property. I have to. Furthermore,
Not only the number of processing steps increases, but also the corners where the mat is extended become thin due to deep drawing, and if this preform is compression-molded as it is, the thinned corners will have a low density and will be completed. There is also a problem in that the strength of deep-drawn parts such as the corners of the above-mentioned wood-based molded product is reduced. Also,
If a large plate-shaped body having a deep drawn portion is formed with a single mat, the mat is dragged into the deep drawn portion, so that the mat is torn around the deep drawn portion and the like, and a desired formed article cannot be obtained. Therefore, it is necessary to apply a patch material made of the same material as the material forming the mat to the deep-drawn portion and then perform compression molding, which complicates the molding operation.

On the other hand, the wet molding method has a problem that a large amount of water is used and a large waste water treatment facility is required for papermaking, and a molded product having a deep-drawn portion using a mat-shaped paper is not manufactured. Since the fiber of the formed mat is entangled, it is more difficult or more difficult than the dry mat method described above, and similar problems such as thinning or tearing of the deep-drawn portion or its periphery are caused. I have a problem.

Therefore, in order to solve these problems, wood fibers with a binder added are deposited in a deposition container without being matted, and the deposited wood fibers are sucked up and held in a suction holding container for direct molding. A method of supplying it into a mold and performing heat compression molding has been considered. Although this method can almost eliminate the above-mentioned problems, it holds the deposited wood fiber when holding it in a suction holding container. It is difficult to apply, and there is a risk that the accumulated wood fibers will collapse, and a large suction device is required.

The present invention is to solve the above problems, and an object of the present invention is to provide a method for producing a wood-based molded product that improves workability, productivity, and production cost, and improves the strength of the resulting molded product. And

[Means for solving problems]

The method for producing a wood-based molded product of the present invention is to deposit wood fibers to which a binder containing a synthetic resin or the like is added on a porous member mounted inside a deposition container, and then contact the suction holding container with the deposition container. Alternatively, the suction holding container is fitted and sucked and held, and then the suction holding container is detached from the deposition container, and the suction holding container is positioned above the lower mold of the mold having the mold opened, and the suction is released. After placing the wood fiber on the mold surface of the lower mold,
It is characterized by molding wood fibers.

The wood fiber used in the present invention is one obtained by loosening wood and the like, and the wood is not particularly limited. For example, red pine,
Examples include cedar, waran, beech, and the like, and rice straw, flax shell, bagasse, and the like can also be used.

A method for defibrating wood or the like to form a wood fiber is not particularly limited, and a method commonly used by those skilled in the art can be used, for example, a method of steaming by pressurizing and a method of mechanically loosening or steaming with the pressure as it is. After that, a method of mechanically loosening under normal pressure can be mentioned.

The binder added to the wood fibers is to bond the wood fibers by compensating for the bondability of the wood fibers themselves.
It is not particularly limited as long as it is possible to integrally bond the wood fibers by heat compression to form a molded body having a desired strength, and its component is preferably a synthetic resin, for example, a thermoplastic resin such as coumarone resin or a phenol resin, A thermosetting resin such as a urea resin may be mentioned, and a water-soluble phenol resin is particularly preferable. Then, they may be used alone or as a mixture.

Further, additives such as a water repellent may be added.

The present invention also deposits wood fibers, to which a binder containing a synthetic resin or the like has been added, on a porous member mounted inside a deposition container, and then causes a suction holding container to contact or fit the deposition container, When suction-holding the deposited wood fibers in the holding container, the suction-holding container is suction-held while pressing the wood-fibers against the suction-holding container at a predetermined pressure, and then the suction-holding container is separated from the stacking container. Then, this is located above the lower mold of the mold that has been opened, and the wood fiber is placed on the mold surface of the lower mold, and then the wood fiber is molded. Manufacturing method. The above-mentioned pressing method is performed, for example, by sandwiching and compressing the accumulated wood fibers between the porous member provided in the suction holding container and the porous member in the deposition container. Further, as the method of holding and compressing, for example, after the suction holding container and the deposition container are combined, the deposition container is placed in the suction holding container, and the outer peripheral surface of the suction holding container and the inner circumference of the deposition container are fitted so that the lid of the tea container is just fitted. A method in which the surfaces are slid up and pushed up, and the wood fibers are compressed by the porous members of both containers, or the suction holding container and the deposition container are aligned, and the porous member of the deposition container or the suction holding container is opposed to the other. The method of pushing up or pushing down the porous member by means of a piston or the like to compress the wood fiber is not particularly limited.

In the present invention, the conditions for compression-molding the wood fibers to which the binder has been added are appropriately determined depending on the materials such as the wood fibers and the binder used, the shape of the molded product, and the required strength.
Although not particularly limited, the molding temperature may be 100 to 220 ° C., the molding pressure may be 20 to 80 kg / cm ² , and the molding time may be 20 seconds to 5 minutes.

[Action]

The method for producing a wood-based molded product of the present invention is one in which wood fibers to which a binder is added are deposited on a porous member in a deposition container, and the wood fibers that have become a lump aggregate are suction-held in a suction-holding container. Therefore, the shape does not easily collapse, and the shape can be filled in the mold as it is. In addition, the method of the present invention is different from the case of sucking wood fibers from a deposition container, since the wood fibers do not float in the air for a moment, the shape of the wood fibers is not deformed, the position is not displaced, and the initial time of sucking The amount of suction is small, and the suction device can be downsized. As a result, the wood fiber can be filled in the molding die without the shape and the position being displaced.

Furthermore, in the method of the present invention, when the accumulated wood fibers are suction-held in the suction container, by pressing the wood fibers, the shape of the aggregate of wood fibers is less likely to collapse, and the positional displacement is more reliable. It can be prevented.

And, in order to compression-mold the wood fiber with the binder added,
Since the wood fibers can be integrally combined into a molded body and the wood fibers are deposited as described above without being matted and directly supplied to the molding die, the fibers are first separated from each other, The wood fibers are easy to flow, the amount of binder used is small, and it can be molded by one-time pressing without degassing by pre-compression or mold opening. Deep drawing such as bending part Even when a molded product having a portion is molded, the molded product can be molded without causing a thin portion or a crack.

Therefore, the step of matting the wood fibers and the step of cutting the mat can be omitted, and a binder for matting can be eliminated. Further, long fibers such as hemp for improving deep drawability and a thermosetting resin or the like for binding them, or a rope made of a thermoplastic resin can be eliminated, and a deep draw portion is provided. When manufacturing a molded product, it is possible to obtain a molded product with excellent strength without performing the preforming process, the reinforcing work such as applying a patch material to the deep-drawn part, or the work of applying steam to the wood fiber of the deep-drawn part. can do.

〔Example〕

An embodiment in which the present invention is applied to a door trim substrate having an armrest of an automobile will be described with reference to the drawings.

First, the production of wood fiber will be described. Chips, which are small pieces made by shaving wood, are steam-defibrated at 160-180 ° C,
Next, the moist wood fiber obtained by defibrating is dried with hot air.

Next, while putting the dried wood fiber in a blender and stirring, 1 to 2% of paraffin as a water repellent and 2 to 10% of a water-soluble fail resin (water content of 50%) as a binder in dry weight. And the water content of the wood fiber is adjusted to obtain a wood fiber to which a binder is added.

Next, the step of binding the wood fiber to which the binder is added to the molding die without forming a mat will be described.

As shown in FIG. 2, the wood fiber M3 added with the binder is supplied from the wood fiber supply pipe 11 by a pressure feeding device (not shown). When the wood fiber M3 exits from the supply pipe 11, the wood fiber M3 falls into the deposition container 14 located below the supply pipe 11. The deposition container 14 is a cup-shaped container having a porous member 15 made of metal or punching metal in the middle and a suction port 16 below the porous member 15. The porous plate 15 is a portion corresponding to the deep-drawn portion of the molded body. Has a curved shape downward, and the rib 17
Supported by. Air is blown from the air blowout port 12 provided around the pipe mouth of the supply pipe 11 to adjust the drop position of the wood fiber M3 that falls from the supply pipe 11, so that a predetermined amount is provided on the porous member 15 of the deposition container 14. Deposit to thickness. At this time, suction is performed through the suction port 16 of the deposition container 14. A cover 13 is provided at the bottom of the supply pipe 11 so as to expand downward.
Since the lower end of 3 is fitted in the deposition container 14, the wood fibers M3 do not deposit on the outside of the deposition container. Next, the cylinder 18 lowers the deposition container to cover the cover 1.
Remove from 3.

Next, as shown in FIG. 3, the cup-shaped suction holding container 19 facing downward is placed in the cylinder 2 so as to face the deposition container 14.
3, the position of the deposition container 14 is adjusted so that the suction holding container 19 fits inside the deposition container 1.
Push up with 8. The suction holding container 19 is a downward cup-shaped container having a porous member 20 made of wire mesh or punching metal in the middle and having a suction port 21 above it.
It has a smaller outer shape than the deposition container 14. The porous member 20 is supported by ribs 22, and the portion corresponding to the deep-drawn portion of the molded body is curved upward. When the suction holding container 19 is fitted so that the outside thereof contacts the inside of the deposition container 14 and the deposition container 14 is raised, the upper surface of the wood fiber M3 deposited in the deposition container 14 contacts the perforated plate of the suction holding container 19. Then, the deposition container 14 is further raised, and the wood fiber M3 is compressed by the porous member 20 of the suction holding container 19 and the porous member 15 of the deposition container 14 as shown in FIG. Next, the wood fiber M3 is sucked from a suction port 21 of the suction holding container 19 by a suction device (not shown) in a state of being in close contact with the porous member 20 of the suction holding container 19. Air flows in through the suction port 16 of the deposition container 14 and the wood fiber M
3 is sucked onto the porous member 20 of the suction holding container 19. While continuing the suction, the deposition container 14 is lowered by the cylinder 18 as shown in FIG. Further, as shown in FIG. 8, the suction side inner shape of the suction holder 19 may be slightly larger than the deposition container 14.

Next, with the wood fiber M3 suction-held, the cylinder 23
Then, the suction holding container 19 is positioned above the lower mold of the mold that has been opened, the suction is released, and the container is dropped and placed on the lower mold 26 of the mold 25 as shown in FIG.

Next, a process of compression-molding the wood fiber M3 will be described.

As shown in FIG. 5, the molding die 25 includes an upper die 27 and a lower die 26. A side plate 28 is fixed around the lower die 26. As shown in FIG.
The wood fiber M3 added with a binder and the like is compressed by the upper mold 27 and the lower mold 26 heated to 150 to 220 ° C. by lowering the upper mold 27 to mold the wood fiber M3. At this time, the gas generated by sucking from the gas vent hole 30 of the upper die 27 through the suction pipe 31 and the pulp 32 from several mm before the bottom dead center of the upper die 27 is released. The molding conditions are, for example, a molding pressure of 20 to 80 kg / cm ² and a molding time of 20 seconds to 5 minutes. Since the fibers are not entangled and are scattered, the fluidity of the fibers is good, and even in the deep drawn portion M5, the wall thickness does not decrease and cracks do not occur. When the mold is opened with suction from the gas vent hole 30 of the upper mold 27, the wood-based molded body M4 is sucked to the upper mold 27. Therefore, when the valve 32 is switched to release the suction, as shown in FIG. 7, the thickness is 2.5 mm and the bending strength is 200 to 350 kg / cm.
It is possible to obtain a defect-free door trim substrate which is made of a wood molded body M4 having ^two or more and having a deep-drawn portion M5 which is an armrest.

In this embodiment, as described above, the suction holding container is fitted inside the deposition container, and the deposition container is raised to compress the wood fiber. However, as shown in FIG. The container 14 'may be fitted inside the suction holding container 19, and as shown in FIG.
4 and the suction holding container 19 may be combined, and the rib 17 ′ supporting the perforated plate 15 may be raised by the piston 24 to raise the perforated plate 15 and compress the wood fiber M 3.

〔The invention's effect〕

As described above, the method for producing a wood-based molded product of the present invention sucks wood fibers to which a deposited binder is added in a state of closely adhering to a suction holding container, and in some cases, the wood fibers are deposited in a deposition container. Since it is held and compressed by a suction holding container, the amount of suction when sucking wood fibers can be small, the suction device can be downsized, and the position when the wood fibers collapse or stick It is possible to manufacture a molded body having excellent strength without causing deviation.

Further, since the wood fibers are suction-held while holding and compressing the deposited wood fibers without forming a mat and supplied to the molding die for compression molding, the wood fibers easily flow and deep drawing is performed. Even in the case of manufacturing a molded product having a portion, it is easy to perform one compression without pre-compression and degassing due to shape opening, and the deep-drawing portion and its periphery do not become thin or crack. Can be molded into. As a result, workability and productivity can be improved, and there is no need for hemp fibers for improving deep drawability and binders and thermoplastic resin ropes therefor,
Raw material cost can be reduced, and a wood-based molded product having excellent strength can be manufactured.

Further, since the step of matting the wood fiber, the step of cutting the mat and the equipment therefor are unnecessary, it is possible to improve the workability and productivity and reduce the equipment cost, and at the same time, a binder for matting. Is unnecessary, and the cutting scraps of the mat and the derived material at the time of molding are not present, so that the yield is improved and the raw material cost can be reduced.

Further, since the wood fibers are directly supplied into the mold without being matted, the filling amount of the wood fibers, that is, the filling density and the filling height can be easily changed, and the desired substrate thickness and density can be obtained. Also, it is easy to change them partially.

[Brief description of drawings]

FIG. 1 is a sectional view of a stacking container and a suction holding container during compression according to an embodiment of the present invention, FIG. 2 is a sectional view of a stacking container during deposition of wood fibers according to an embodiment of the present invention, and FIG. FIG. 4 is a cross-sectional view of a deposition container and a suction holding container in which wood fibers are deposited according to an embodiment of the present invention, and FIG. 4 is a cross-sectional view of a suction holding container and a deposition container in which wood fibers are suction-held according to an embodiment of the present invention. FIG. 5 is a sectional view of a molding die on which wood fibers according to an embodiment of the present invention are mounted, FIG. 6 is a sectional view of a molding die at the time of molding according to an embodiment of the present invention, and FIG. FIG. 8 is a perspective view of a wood-based molded product manufactured according to one embodiment of the present invention, FIG. 8 is a cross-sectional view of a deposition container and a suction holding container at the time of compression according to one embodiment of the present invention, and FIG. FIG. 10 is a perspective view of a conventional wood fiber mat, and FIG. 11 is a conventional cross-sectional view of a deposition container and a suction holding container in which wood fibers are deposited. FIG. 12 is a sectional view of a molding die on which the mat according to the present invention is mounted, and FIG. 12 is a sectional view of the molding die at the time of molding the mat according to the prior art. In the figure, 14 ... deposition container, 15, 22 ... porous member 16, 21 ... suction port, 18, 23 ... cylinder 19 ... suction holding container

Claims (2)

[Claims] 1. After depositing wood fibers to which a binder containing a synthetic resin or the like has been added on a porous member mounted inside a deposition container,
A suction holding container is brought into contact with or fitted to the deposition container, suction holding is performed in the suction holding container, and then the suction holding container is separated from the deposition container, and the suction holding container is opened above the lower mold of the mold. And releasing suction to place the wood fiber on the mold surface of the lower mold, and then molding the wood fiber. 2. After depositing wood fibers to which a binder containing a synthetic resin or the like has been added on a porous member mounted inside a deposition container,
When the suction holding container is brought into contact with or fitted to the stacking container and the stacked wood fibers are held by suction in the suction holding container,
The wood fiber is suction-held in the suction-holding container while being pressed against the suction-holding container with a predetermined pressure, and then the suction-holding container is detached from the deposition container, and the wood-fiber is placed above the lower mold of the mold that has been opened. A method for producing a wood-based molded product, which comprises locating the wood fibers, placing the wood fibers on a mold surface of the lower mold, and then molding the wood fibers.