JP4031820B2 - Manufacturing method of fiber panel - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a fiber panel, and in particular, an open cell grid composed of a plurality of ribs, a continuous flat plate covering one opening of the grid, and a flange covering a part of the other opening. Are related to a method of manufacturing a fiber panel having a structure integrally formed with dense compressed fibers.
[0002]
[Prior art and problems]
Japanese Laid-Open Patent Publication No. 9-195440 discloses a method for manufacturing a fiber panel having an open cell lattice.
An outline of such a manufacturing method is as follows.
[0003]
First, a raw material A such as wood fiber or recycled paper is pulped with a strong stirring force to obtain a fiber-containing slurry S having a moisture concentration of about 99% [see FIG. 7 (a)].
Subsequently, the slurry S is formed on the mold 50 including the porous carrier 51 shown in FIG. 4 and a plurality of elastomer pads 52 geometrically arranged and fixed on the plate surface of the porous carrier 51. [See FIG. 7 (b)], and dehydrated by pressing (prepress) with a flat plate from above and below the mold 50 and suction from the lower surface of the mold 50, and the slurry S has a moisture concentration of 50. % Of dehydrated cake K (see FIG. 7C).
[0004]
Thereafter, the mold 50 is conveyed to the hot press 60, and under pressure, the dehydrated cake K is heated and compression-molded by applying vertical pressure to the mold 50 (see FIG. 8 (a)). The molded product X is about%.
At this time, as shown in FIG. 5, the elastomer pad 52 constituting the mold 50 is deformed flat by the compressive force of the press, and the dehydrated cake K filled between the pads is perpendicular to the mold. Compressed not only in the parallel direction, but formed into a fiber panel having a dense open cell lattice.
[0005]
After the molding is completed, the molded product X is taken out from the hot press 60 together with the mold 50, and the molded product X is removed from the mold 50 (see FIG. 8B).
[0006]
Through the steps described above, the open cell lattice 71 constituted by the plurality of ribs shown in FIG. 6, the continuous flat plate 72 covering one opening of the lattice 71, and the flange covering a part of the other opening 73 can be manufactured as a fiber panel 70 having a structure integrally formed with dense compressed fibers.
[0007]
Here, during the manufacturing process of the fiber panel 70 having the open cell lattice, the amount of power required for the heat compression molding process of the dewatered cake K by the hot press 60 is approximately 10 kWh per 1 kg of the molded product, and the total power consumption Nearly 80% of this was occupied in this process, raising the manufacturing cost.
[0008]
This is apparently due to the fact that the moisture concentration of the dewatered cake K at the time of shifting to the heat compression molding process is as high as about 50%. Dehydration alone has its limit in its dehydration effect. In particular, in the production of the fiber panel 70 having the open cell lattice, which is the subject of the present invention, the dewatering of the thin rib portions constituting the open cell lattice is particularly a bottleneck. This is because it was difficult to bring the moisture concentration of the dewatered cake K to less than 50% before the heat compression molding process as the final process.
[0009]
Therefore, the fiber panel having an open cell lattice, which is the subject of the present invention, is a lightweight and high-strength panel, which can be used in a wide range of applications such as housing members, joinery or furniture, and can effectively use recycled resources such as waste paper. Although it was expected to be a product that could be planned, because of its high manufacturing cost, demand was slow.
[0010]
The present invention has been made in view of the problems of the above-described conventional method for manufacturing a fiber panel having an open cell lattice, and its purpose is to provide total power including all steps for manufacturing a product. An object of the present invention is to provide a method for manufacturing a fiber panel having an open cell lattice at a low cost by reducing consumption.
[0011]
[Means for Solving the Problems]
As a result of repeated studies to achieve the above-mentioned object, the present inventors paid attention to electroosmosis dehydration, which has been widely known as a dewatering technique for sludge, and the electroosmosis dehydration and the compression performed conventionally.・ By using mechanical dehydration called suction together with dehydration of the fiber-containing slurry placed on the mold, the moisture concentration of the dehydrated cake is brought to a predetermined level of less than 50% before the heat compression molding process. In addition, the amount of power required for heat compression molding of dehydrated cakes whose moisture content has been reduced to this level can be greatly reduced compared to the conventional method. The present inventors have found that the total power consumption can be suppressed even when the increase in power consumption is taken into consideration.
[0012]
That is, the present invention uses a mold frame composed of a porous carrier and a plurality of elastomer pads geometrically arranged and fixed on the plate surface of the porous carrier, and is formed with a plurality of ribs. In a method of manufacturing a fiber panel having a structure in which a cell lattice, a continuous flat plate covering one opening of the lattice, and a flange covering a part of the other opening are integrally formed of dense compressed fibers The step of placing the fiber-containing slurry on the mold, and the fiber-containing slurry placed on the mold are pressed by a flat plate from above and below the mold and from the lower surface of the mold Squeezing and suction dewatering by suction, applying a DC voltage between the flat plates for pressing to electroosmotic dewater the fiber-containing slurry to form a dehydrated cake having a moisture concentration of 35 to 45%, and on the mold the dehydrated cake, formwork · In the press under due platen from downward, a by applying a high frequency voltage dehydrated cake with high frequency dielectric heating, heat compression molding was aspirated from the upper and lower direction of the mold between the press platen And a fiber panel manufacturing method comprising a step of forming a molded article having a moisture concentration of 10% or less.
[0013]
Here, the dehydration of the fiber-containing slurry placed on the mold is performed by using both electroosmotic dehydration and mechanical dehydration called squeezing / suction, so that the moisture concentration is 35 to 45% before the heat compression molding step. It is important to bring even the dehydrated cake.
This means that a considerable amount of power is required for heat compression molding of dehydrated cake exceeding 45%, and when considering the increase in power consumption due to the combined use of electroosmotic dehydration in the previous process, total power consumption It is difficult to bring dehydrated cakes of less than 35% to a dehydrated cake in a short time even if electroosmotic dehydration and mechanical dehydration are used in combination. This is not preferable because the power consumption in the process increases rapidly.
[0014]
In the present invention, the step of placing the fiber-containing slurry on the mold may be a process of placing the fiber-containing slurry on the mold only by the action of gravity, as in the prior art. It is preferable that the fiber-containing slurry having a moisture concentration of 65 to 80% is placed while sucking from the lower surface of the mold.
This is preferable in view of the reduction of the total power consumption for manufacturing, because the lower the moisture concentration of the fiber-containing slurry as the raw material, the less the amount of power required for subsequent dehydration and the like. However, the formwork used in the present invention is one in which a plurality of elastomer pads are geometrically arranged and fixed on the plate surface of the porous carrier as described above. In the case of the raw material, it is preferable that the raw material is filled between the elastomer pads and the strength of the product is reduced, so that the strength of the product is reduced. However, in the case of a fiber-containing slurry having a moisture concentration exceeding 80% even if sucked, it is preferable because the effect of reducing the total power consumption is small. .
[0015]
Further, in the present invention, the step of heat compression molding a dewatered cake on the formwork, in a press under due platen from the upper and lower direction of the mold, a high frequency voltage is applied between the press platen The dehydrated cake is heated by high-frequency dielectric and sucked from above and below the mold .
This is because, as described in the upper part, the mold used in the present invention is composed of an elastomer pad made of an elastic material such as silicon rubber having a low thermal conductivity. This is because it is possible to heat the dehydrated cake itself more efficiently by applying a high-frequency voltage than by heat compression molding using a heated flat plate press that expects high temperature. When high-frequency dielectric heating is performed, the evaporated liquid component is sucked and removed by suction from above and below the mold, increasing the insulation between the flat plates, and efficient dielectric heating of the dehydrated cake. This is because it becomes possible .
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a manufacturing method of a fiber panel concerning the above-mentioned present invention is described in detail based on a drawing.
[0017]
The molds used in the present invention can be the same as the conventional ones. That is, as shown in FIG. 4, the mold 50 is composed of a porous carrier 51 and a plurality of elastomer pads 52 geometrically arranged and fixed on the plate surface.
As shown in FIG. 5, each of the elastomer pads 52 of the mold 50 expands in parallel to the carrier from the center toward the outside when the pad is compressed, and is filled between the pads. The fiber has a predetermined size and shape so that the fibers located above the pad and under the enlarged pad can be compressed simultaneously.
[0018]
The porous carrier 51 has a structure in which a plurality of through holes are formed in a generally rectangular metal plate, and a belt-like press stopper is provided on the peripheral plate surface as a reinforcement as shown in FIG. 53 is attached. The porous carrier 51 may be constituted by a single plate or may be constituted by overlapping a plurality of plates.
The elastomer pad 52 is formed of a material having sufficient elasticity, and can be formed using various synthetic rubbers including, for example, silicon rubber and chloroprene rubber. And is particularly excellent when considering elasticity. Then, the elastomer pad 52 is formed into a trapezoidal body having a hexagonal cross section as shown in an enlarged manner in FIG. It can be a square.
[0019]
In the manufacturing method according to the present invention, the fiber-containing slurry S is first placed on the mold 50.
The fiber-containing slurry S is placed in the same manner as before, for example, after pulping the raw material A such as wood fiber and recycled paper with a strong stirring force, and adjusting the fiber-containing slurry S to a moisture concentration of about 99%. The fiber-containing slurry S may be cast on the mold 50 only by the action of gravity. However, as shown in FIG. It is preferable to employ a method in which the fiber-containing slurry S adjusted to ˜80% is placed on the mold 50. This is preferable because the fiber-containing slurry S can be sufficiently filled between the elastomer pads 52 as the mold, the moisture concentration can be reduced, and the power required for subsequent dehydration can be reduced.
[0020]
Here, according to the test conducted by the present inventors, the suction pressure in this placing step depends on the moisture concentration of the slurry S, but the purpose can be achieved if suction is performed at about −650 mmHg. When the water concentration of the slurry S is less than 65%, the raw material is not sufficiently filled on the mold even if the suction pressure is increased, and when it exceeds 80%, This is not preferable because the effect of reducing the total power consumption is small.
[0021]
Subsequently, the fiber-containing slurry S placed on the mold 50 is dehydrated to a dehydrated cake K having a moisture concentration of 35 to 45%.
In the dehydration step of the fiber-containing slurry S, electroosmosis dehydration and mechanical dehydration such as squeezing / suction are performed in combination. That is, as shown in FIG. 2, the fiber-containing slurry S is squeezed and sucked and dehydrated by pressing with a flat plate from above and below the mold 50 and suction from the lower surface of the mold 50. When a DC voltage is applied between the flat plates, a current flows through the fiber-containing slurry S sandwiched between the flat plates. Here, the fibrous material dispersed in the slurry S is usually in a negatively charged state, and the surrounding liquid in contact with the fibrous material is charged positively with a polarity opposite to the surface charge of the fibrous material. is doing. Therefore, when a voltage is applied from a DC power source with the upper pressing flat plate as the positive electrode and the lower pressing flat plate as the negative electrode, the liquid contained in the slurry S is between the fibrous materials due to the action of the electroosmosis phenomenon. Is moved to the lower pressing flat plate side as a capillary tube and drained to the outside by suction from the lower surface of the mold 50. Thereby, the fiber-containing slurry S can be dehydrated up to a dehydrated cake K having a moisture concentration of 35 to 45%, which could not be achieved only by mechanical dehydration called compression / suction.
[0022]
Here, according to a test conducted by the present inventors, the compression pressure applied by the flat plate for press is 10 to 12 kgf / cm ^2, and the suction pressure from the lower surface of the mold is about −650 mmHg. The voltage of the DC power source applied between the flat plates for pressing is 200 to 400 V. When the electroosmotic dehydration and mechanical dehydration are performed in combination for 45 to 90 seconds, dehydration with a moisture concentration of 35 to 45% is performed. The fiber-containing slurry S could be dewatered up to cake K.
The dehydration by suction may be performed not only from the lower surface of the mold 50 but also from the upper side of the mold 50 by providing pores in the upper press platen as shown.
[0023]
Next, the dehydrated cake K on the mold 50 is heat compression molded to obtain a molded product X having a moisture concentration of 10% or less.
As shown in FIG. 3, the heat compression molding process of the dewatered cake K is performed by applying a high-frequency voltage between the flat plates for pressing under a press with a flat plate from the upper and lower sides of the mold 50. It is assumed that the cake K itself is subjected to high-frequency dielectric heating . This is because the formwork used in the present invention is composed of the elastomer pad 52 made of an elastic material such as silicon rubber having a low thermal conductivity as described above, so that it is heated to expect conduction heat transfer. was than heated compression molding by Release press flat, the application of the high-frequency voltage, because the person who was to cause a dielectric heating in dehydrated cake itself becomes possible efficient heating.
Further , when the dehydrated cake K is subjected to high-frequency dielectric heating, as shown in FIG. 3, when the evaporated liquid is sucked and removed by suction from above and below the mold 50, Therefore, the dielectric heating of the dehydrated cake K can be performed efficiently .
As shown in the figure, the press surface of the press platen is heated to about 120 to 160 ° C. by a heater or a heating medium, and dehydration is performed by conduction heat transfer from above and below the mold 50. A configuration in which heating of the cake K is also used is preferable because unevenness of drying of the dehydrated cake K due to nonuniform application of high-frequency power can be eliminated.
[0024]
Here, according to the test conducted by the present inventors, the compression pressure applied to the dewatered cake K on the mold 50 by the flat plate for press in this heat compression molding step is about 10 to 12 kgf / cm ² . The high frequency voltage applied between the flat plates for pressing is a high frequency voltage of 13.56 MHz and a voltage of 200 V for about 120 to 180 seconds. The following molded product X could be obtained.
[0025]
In addition, according to the test conducted by the present inventors, the amount of electric power when the dehydrated cake K having a moisture concentration of about 50% is heated and compression-molded by a hot press is almost the same as described in the section of the prior art. Although it was about 10 kWh per 1 kg of the molded product, the dehydrated cake K, which had a moisture concentration of 35 to 45%, was obtained by combining electroosmotic dehydration and mechanical dehydration called pressing / suction in the previous process. The amount of electric power when heat-press-molding with a press as in the past can be largely reduced to about 4 to 6 kWh per kg of the molded product, considering the increase in power consumption due to the combined use of electroosmotic dehydration in the previous process. However, it was confirmed that the total power consumption can be kept low.
[0026]
As mentioned above, although embodiment of the manufacturing method of the fiber panel concerning this invention was described, this invention is not limited to above-mentioned embodiment, In the range of the technical idea of this invention, various Variations and changes are possible.
[0027]
For example, in the above-described embodiment, a batch type is used as the mold 50, but the porous carrier constituting the mold 50 is belt-shaped or wheel-shaped so It is good also as what was moved so that a process might be received continuously.
[0028]
Moreover, in the said embodiment, the flat plate for press used in the dehydration process of the fiber containing slurry S and the flat plate for press used in the heat compression molding process of the dewatering cake K were described as different things. However, the same thing may be used together, and in that case, a dehydration process and a subsequent heat compression molding process may be performed continuously while performing press clamping.
[0029]
【The invention's effect】
As mentioned above, the manufacturing method of the fiber panel concerning this invention demonstrated the water density | concentration 35-35 by using together the mechanical dehydration called electroosmosis dehydration and pressing and suction | inhalation for a fiber containing slurry before a heat compression molding process. The dehydrated cake is dewatered to 45% dehydrated cake, and the dehydrated cake is pressed by a flat plate from above and below the mold, and a high frequency voltage is applied between the flat plates for pressing to dehydrate the dehydrated cake. It has the greatest feature in that it is heated and compression-molded by sucking from above and below the mold to make it a molded product with a moisture concentration of 10% or less, thereby reducing the power consumption in the heat-compression molding process. There is an effect that a fiber panel having an open cell lattice can be manufactured at a low cost, which can be greatly reduced.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a conceptual diagram showing an embodiment of a fiber-containing slurry placing process during a fiber panel manufacturing process according to the present invention.
FIG. 2 is a conceptual diagram showing an embodiment of a fiber-containing slurry dewatering step during a fiber panel manufacturing process according to the present invention.
FIG. 3 is a conceptual diagram showing an embodiment of a heat compression molding process of a dehydrated cake during the manufacturing process of the fiber panel according to the present invention.
FIG. 4 is a perspective view showing an embodiment of a mold used for manufacturing a fiber panel.
FIG. 5 is a cross-sectional view showing a state during a heat compression molding process of a raw material.
FIG. 6 is a perspective view showing a fiber panel that is a molded article.
FIGS. 7A and 7B are diagrams illustrating a conventional fiber panel manufacturing process, where FIG. 7A is a process for manufacturing a raw slurry, FIG. 7B is a process for placing a raw material on a mold, and FIG. It is the figure which showed each dehydration process.
FIGS. 8A and 8B are diagrams showing a conventional fiber panel manufacturing process, where FIG. 8A shows a raw material heat compression molding process, and FIG. 8B shows a product peeling process from a mold.

Claims (2)

An open cell lattice comprising a plurality of ribs using a formwork composed of a porous carrier and a plurality of elastomer pads geometrically arranged and fixed on a plate surface of the porous carrier, and the lattice In the method of manufacturing a fiber panel having a structure in which a continuous flat plate covering one opening of the first member and a flange covering a part of the other opening are integrally formed of dense compressed fibers, The step of placing the fiber-containing slurry, and the fiber-containing slurry placed on the mold are pressed and sucked and dehydrated by pressing with a flat plate from above and below the mold and suction from the lower surface of the mold. In addition, a DC voltage is applied between the flat plates for press to electroosmose dehydrate the fiber-containing slurry to obtain a dehydrated cake having a moisture concentration of 35 to 45%, and the dehydrated cake on the mold is formed into a mold. From above and below In the press under by the board, the inter-press platen and by applying a high frequency voltage dehydrated cake with high frequency dielectric heating, the heated compression molding was aspirated from the upper and lower direction of the mold and a water content of 10% or less A process for producing a fiber panel comprising the steps of:   The step of placing the fiber-containing slurry on the mold is a process of placing the fiber-containing slurry having a moisture concentration of 65 to 80% while sucking from the lower surface of the mold. The manufacturing method of the fiber panel of description.

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