JP7446637B2 - How to make water absorbent board - Google Patents

Description

TECHNICAL FIELD The present invention relates to a water absorbent board containing a glass foam material and a method for manufacturing the same.

A bath mat (foot wiping mat) is placed on the floor in front of the entrance of a domestic bath to absorb the moisture that drips from the body to the feet after taking a bath. BACKGROUND ART Conventionally, there are bath mats in which the entire mat is made of a highly absorbent natural fiber material such as cotton fiber. However, the water sucked into the fibers is difficult to dry, causing bacteria and mold to grow, resulting in unsanitary conditions.

On the other hand, in recent years, bath mats made of diatomaceous earth, which has high water absorption and quick drying properties, have been commercially available. However, diatomaceous earth is a natural resource and may be depleted in the future. New materials are needed to realize a sustainable society.

By the way, a glass foam material has been developed as a new water-absorbing material, which is used as a soil improvement material to improve the air permeability and drainage of soil. For example, in JP-A-11-236232, 96% by weight or less of coarsely ground glass powder having a particle size distribution of 0.21 mm or more and 2.38 mm or less obtained by pulverizing glassy waste material and a particle size distribution of less than 0.21 mm are disclosed. A mixed powder obtained by adding and mixing 0.1 to 3% by weight of silicon carbide to the vitreous blended powder to a vitreous blended powder made by blending 4% by weight or more of finely pulverized glass powder having a A manufacturing method is disclosed in which glass is heated to a temperature higher than its softening point and then cooled (Patent Document 1). According to Patent Document 1, a vitreous foam that can be used as a lightweight civil engineering and construction material that has a bulk density of 1.2 g/ ^cm3 or less and a water absorption rate of 20% or less and has good workability can be produced inexpensively and reliably. It is said that it can be obtained in

Furthermore, in the manufacture of small items such as coasters that require water absorption, there have been methods in which a glass foam material is powdered, placed in a mold, compressed, and then baked to harden (fired).

Japanese Patent Application Publication No. 11-236232

However, products manufactured by firing a powdered glass foam material have the problem of having irregular irregularities on the surface, easily producing defective products, and having a low yield. In particular, products such as bath mats, which have a larger surface area than coasters, are more likely to have unevenness and are difficult to manufacture. Another problem is that it is difficult to cut due to its low strength and brittleness.

The present invention was made in order to solve the above problems, and it is possible to perform processing such as cutting by improving strength and improving brittleness, and to improve yield. The purpose of the present invention is to provide a water-absorbent board and a method for manufacturing the same.

In order to solve the problem of increasing the strength of a water absorbent board containing a glass foam material, the water absorbent board according to the present invention is characterized by containing silica sand, slaked lime, and pulp together with the glass foam material.

In addition, as an aspect of the present invention, the ingredients of the raw materials in the manufacturing process include 30 wt% to 50 wt% of the glass foam material, 5 wt% to 15 wt% of silica sand, 15 wt% to 35 wt% of slaked lime, and 20 wt% to 35 wt% of pulp. It may be configured to include.

Furthermore, as one aspect of the present invention, the water-absorbing board is preferably used as a bath mat, a coaster, a soap holder, a pot plate, and a draining mat on which washed dishes are placed.

The method for manufacturing a water absorbent board according to the present invention solves the problem of increasing the strength of a water absorbent board containing a glass foam material and preventing the occurrence of surface irregularities. A dough making step involves mixing silica sand, slaked lime, and pulp with water to create a slurry-like dough; a plate-like dough forming step in which the slurry-like dough is formed into a plate shape of a predetermined thickness; A first drying step in which the dough is heated and dried until the moisture content becomes 40% or less, and a solidification step in which the dough, which has been dried to a moisture content of 40% or less, is heated and solidified while pressurized above atmospheric pressure. and a second drying step of drying the solidified plate-shaped dough to a moisture content of 15% or less while heating it at a higher temperature than the first drying step.

Further, as an aspect of the present invention, in the first drying step, the dough is heated within a temperature range of 30° C. to 50° C., and in the second drying step, the dough is heated within a temperature range of 90° C. to 100° C. It may also be heated internally.

Further, as an aspect of the present invention, in the solidification step, heating may be performed at a temperature of 180° C. for 24 to 48 hours in an environment with a maximum pressure of 1 MPa or less.

Further, as one aspect of the present invention, in order to solve the problem of efficiently solidifying the dough, between the first drying step and the solidifying step, a plurality of sheets of the dough dried in the first drying step are It may also include a stacking step of stacking the fabrics in the vertical direction and arranging metal pads each having a vertically penetrating ventilation hole for every predetermined number of fabrics.

According to the present invention, processing such as cutting can be performed by improving strength and brittleness, and yield can be improved.

1 is a schematic diagram showing an embodiment of a method for manufacturing a water absorbent board according to the present invention. It is a flow chart showing the flow of each manufacturing process of this embodiment. It is a perspective view showing the metal pad used in the stacking process in this embodiment. It is a photographic image showing the state in which the water absorbent board according to the present invention is processed into a bath mat.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a water absorbent board and a method for manufacturing the same according to the present invention will be described below with reference to the drawings.

As shown in FIGS. 1 and 2, the method for manufacturing a water-absorbing board of this embodiment includes a dough preparation process in which a raw material P is mixed with water W to create a slurry-like dough M, and a slurry-like dough M is prepared in a predetermined manner. A plate-shaped dough forming step S2 in which the dough M is formed into a plate shape with a thickness of S4, a solidifying step S5 in which the stacked dough M is heated and solidified while being pressurized, a second drying step S6 in which the solidified plate-shaped dough M is dried, and water absorbency formed by the second drying step S6. It includes a product processing step S7 in which the board 1 is processed into a predetermined product by cutting, polishing, or the like. Each step will be explained in detail below.

The dough creation step S1 is a step of mixing the raw material P and water W to create the dough M that will become the base material for the water-absorbing board 1. In this embodiment, the ingredients of the raw material P include silica sand, slaked lime, and pulp along with a water-absorbing glass foam material. Silica sand is contained to increase the strength and hardness of the water absorbent board 1, slaked lime is contained to solidify the fabric M, and pulp is contained to increase the toughness of the water absorbent board 1 to prevent cracks.

Further, the glass foam material is powdered and mixed with silica sand in advance. In this embodiment, the average particle size of the glass foam material is about 60 to 320 mesh, the average particle size of silica sand is about 60 to 260 mesh, and the average particle size of slaked lime is about 200 to 320 mesh. Soak the pulp in water in advance to dissolve it evenly. Moreover, when coloring the water absorbent board 1, it is preferable to mix colored powder with slaked lime. Then, each component is mixed with water and stirred by a mixer 2 to create a slurry-like dough M.

At this time, the blending ratio (component ratio) of each raw material P is preferably 30 wt% to 50 wt% of the glass foam material, more preferably 45 wt%. On the other hand, if the blending ratio of the glass foam material is higher than the range, the dough will not hold together when forming the dough into a plate shape in the plate-like dough forming step S2, and it will not be possible to form the dough into a plate shape. In addition, if the blending ratio of the glass foam material is less than the above range, as shown in Example 2 below, the water absorption rate of the manufactured water absorbent board will be low, the water absorption rate will be slow, and the water absorption performance will decrease. I don't like it.

Further, the blending ratio of silica sand is preferably 5 wt% to 15 wt%, more preferably 10 wt%. On the other hand, as shown in Example 2 below, the density of silica sand increases almost in proportion to the blending ratio, and if the density is less than this range, the strength decreases and it is more likely to break than a typical diatomaceous earth bath mat. I don't like it.

Further, the blending ratio of slaked lime is preferably 15 wt% to 35 wt%, more preferably 25 wt%. On the other hand, as shown in Example 2 below, the water absorption rate of slaked lime decreases in almost inverse proportion to the blending ratio, so if the blending ratio of slaked lime is greater than the range, the water absorption rate and water absorption rate will increase. It will drop. In addition, if the blending ratio of slaked lime is less than the range, the dough will not hold together well, and similarly to when the blending ratio of glass foam material is high, when forming the dough into a plate shape in the plate-shaped dough forming step S2. This is undesirable because the dough does not come together and cannot be formed into a plate shape.

Further, the blending ratio of pulp is preferably 20 wt% to 35 wt%, more preferably 20 wt%. On the other hand, if the blending ratio of pulp is higher than the range, autoclave curing cannot be completed in the solidification step S5. In addition, as shown in Example 2 below, the water absorption rate and water absorption rate of pulp decrease almost in proportion to the blending ratio, so if the blending ratio is higher than the range, the water absorption rate and water absorption rate will decrease. This is not desirable as it decreases significantly.

Therefore, in this embodiment, each raw material P and water are weighed so that each blending ratio becomes the specified value, taking into consideration the water absorption performance and strength, as well as the condition of the fabric in the manufacturing process and the autoclave curing condition. After that, it is put into mixer 2.

The plate-shaped dough forming step S2 is a step in which the slurry-like dough M created in the dough creating step S1 is shaped into a plate. In this embodiment, in order to continuously form a plate-shaped dough M having a predetermined thickness, a belt conveyor 3 and a roller 4 for winding up the dough M carried by the belt conveyor 3 are provided. .

Specifically, the slurry-like dough M is poured onto the belt conveyor 3 in operation. The belt of the belt conveyor 3 is made of water-permeable non-woven fabric such as felt, and the slurry-like dough M loses water while being conveyed and becomes clay-like.

The roller 4 is installed at the end of the belt conveyor 3, and the fabric M can be peeled off from the roller 4 when the fabric M has been wound up a predetermined number of times. In other words, the thickness of the plate-shaped material M can be adjusted by the number of times it is rolled up before being peeled off. In this embodiment, the thickness of the fabric M before being rolled up is approximately 1.1 mm to 1.7 mm, and by peeling off the rolled fabric M after the roller 4 has rotated 4 to 12 times, The thickness of M can be adjusted to approximately 4.4 mm to 20.4 mm. The thickness of the plate-shaped fabric M formed in this plate-shaped fabric forming step S2 is determined based on the design thickness of the water-absorbing board 1 that will become the product, taking into account shrinkage due to moisture loss during the subsequent drying process, etc. It is slightly thicker (approximately 0.5 mm to 2.0 mm) than the original.

Then, the fabric M formed to a predetermined thickness is cut to a size of 1220 mm in width and 2440 mm in length, and about 10 pieces are stacked on the cart 6 by a stacking machine (not shown).

Note that the plate-shaped dough forming step S2 is not limited to the step of forming using the belt conveyor 3 and rollers 4 as described above, but may be formed by pouring the slurry-like dough M into a mold or the like.

The main purpose of the first drying step S3 is to reduce the water content of the dough M, and specifically, while heating the dough M formed into a plate shape, the water content of the dough M is 40% or less. This is the process of drying it until it becomes . In the first drying step S3 in this embodiment, a tunnel type dryer 5 is used.

The tunnel type dryer 5 in the first drying step S3 includes a drying conveyance path 51 formed in a tunnel shape with a length of about 48 m, a height and a width of about 2.5 m, and It has a heat exchanger (not shown) disposed inside, and rails on which the cart 6 carrying the fabric M can run are laid on the floor surface. Further, the drying conveyance path 51 is provided with exhaust ports 53 at intervals of 2 m for exhausting water vapor to the outside. Further, hot air blowing units (not shown) that blow hot air are provided at the upper and lower parts of the entrance and exit of the drying conveyance path, and hot air is blown from above and below like a curtain. The structure is such that low-temperature air does not flow into the interior from the outlet.

The dough M formed into a plate shape is carried into the tunnel while being placed on a trolley 6. In this embodiment, a plurality of carts 6 are lined up inside the drying conveyance path 51 and dried.

The dough M is heated by the heat exchanger inside the drying conveyance path 51, and moisture gradually evaporates. The evaporated water vapor is discharged to the outside of the tunnel via the exhaust port 53. Therefore, the air inside the tunnel does not reach a saturated amount of water vapor, and the fabric M can be dried to have a water content of 40% or less. The moisture content in this embodiment is also referred to as moisture percentage, and is the proportion of moisture contained in the fabric M expressed as a percentage of mass. The measurement method may be the loss on drying method or a commercially available moisture meter. In this embodiment, the temperature inside the tunnel is maintained within a temperature range of 30° C. to 50° C., and the water content is reduced to 40% or less by heating the tunnel for approximately 10 to 24 hours. By setting the moisture content of the fabric M to 40% or less in the first drying step S3 in this way, the solidification time in the solidification step S5 and the drying time in the second drying step S6, which will be described later, can be shortened. On the other hand, if the drying temperature is higher than the range, the drying time will be shortened but cracks will occur. Furthermore, if the drying temperature is lower than the above range, it will take a long time to reduce the water content to 40% or less.

The stacking step S4 is a step performed between the first drying step S3 and the solidifying step S5 in order to efficiently solidify the dough M. In other words, the solidifying step S5 in this embodiment uses an autoclave 8 that can heat the dough M while pressurizing it, but by increasing the number of boards that can be placed in the autoclave 8 at one time, production efficiency related to solidifying can be improved. This is a process performed to increase the

Specifically, a stacking machine (not shown) stacks the plurality of fabrics M dried in the first drying step S3 in the vertical direction. Further, when the fabrics M are stacked, uneven heating occurs between the fabrics M at the upper and lower ends and the fabric M at the center, so metal pads 7 are arranged every predetermined number of fabrics so that the heat is transmitted to the inside. As shown in FIG. 3, the metal pad 7 has a vertically penetrating vent hole 71 formed therein, and in this embodiment is made of stainless steel in consideration of heat conductivity and corrosion resistance. In this embodiment, one metal pad 7 is arranged for every 10 plate-shaped fabrics M stacked on the trolley 6.

The solidifying step S5 is a step of heating and solidifying the dough M, which has been dried to a moisture content of 40% or less in the first drying step S3, while pressurizing it to atmospheric pressure or higher. In this embodiment, in the stacking step S4, the fabric M placed on the trolley 6 is placed in the autoclave 8, and the temperature is 180°C, which is lower than the temperature at which general glass softens (around 730°C) at a maximum pressure of 1 MPa or less. Heat at ℃ for about 24 to 48 hours. Thereby, the fabric M can be solidified while maintaining the shape of the many holes provided in the glass foam material. Moreover, the dough M can also be sterilized by heating at a temperature of 180°C.

At this time, since the metal pad 7 transmits heat to the center side of the dough M, uneven heating can be reduced. Further, the evaporated water vapor can be released to the outside of the fabric through the vent hole 71 of the metal pad 7.

Note that when the maximum pressure is higher than 1 Mpa or when the heating temperature exceeds 180° C., the product becomes hard due to the hydration reaction and processing such as cutting becomes difficult. In particular, if the maximum pressure exceeds 3 MPa or the heating temperature exceeds 300° C., the components may change, which is not preferable.

Moreover, if the heating time is shorter than the range, the hydration reaction will be insufficient and solidification will not occur. Furthermore, if the heating time is longer than this range, although a sufficient hydration reaction can be obtained, the fuel cost required for heating becomes high, which is not preferable.

In the second drying step S6, the solidified plate-shaped dough M is heated at a higher temperature than the first drying step S3, and is dried so that the moisture content of the dough M becomes 15% or less. In the second drying step S6 in this embodiment, similarly to the first drying step S3, a tunnel type dryer 5 is used, and the fabric M is carried in an upright state on a conveyor 52 and dried. Here, the drying temperature in the second drying step S6 is heated within a temperature range of 90° C. to 100° C., which is higher than the drying temperature in the first drying step S3, in order to sufficiently dry. In this embodiment, in order to prevent cracks, the material is heated in the tunnel dryer 5 for 4 to 72 hours to reduce the water content to 15% or less. As a result, the water absorbent board 1 with less unevenness on the surface is completed.

Product processing step S7 is a step of processing the water absorbent board 1 as necessary. In this embodiment, the water-absorbent board 1 is cut by a cutting machine 9 such as a milling machine, a polishing machine (not shown) such as a sand machine, etc., to a draining mat on which bath mats, coasters, soap holders, bowl plates, and washed tableware are placed. etc.

According to the water absorbent board and its manufacturing method of the present embodiment as described above, the following effects can be achieved.
1. By drying and solidifying at a low temperature over a long period of time, it is possible to manufacture the water absorbent board 1 with less unevenness on the surface, and the yield can be suppressed by reducing the occurrence of defective products.
2. Since the water-absorbing board 1 has increased strength due to the pulp contained therein, various products can be created by cutting or the like.
3. Since the water-absorbing board 1 is manufactured at a temperature lower than the softening temperature of glass, it can be solidified while leaving the pores of the glass foam material, so it can exhibit high water-absorbing properties.
4. By arranging a metal pad 7 in the middle of a plurality of stacked fabrics M, a large number of boards can be solidified while suppressing uneven heating.
5. The glass foam material, which is the main raw material, is manufactured by recycling glass products such as empty bottles, so it can contribute to the realization of a sustainable society.

Next, an example of a water absorbent board manufactured by the method for manufacturing a water absorbent board according to the present invention will be described.

In Example 1, a water absorbent board containing 45 wt% of glass foam material, 10 wt% of silica sand, 25 wt% of slaked lime, and 20 wt% of pulp was manufactured using the method for manufacturing a water absorbent board according to the present invention, and the impact test and bending strength test were performed. and a water absorption performance test.

First, the impact test will be explained. The impact test was conducted based on the method specified in the Chinese national standard (standard name: JC/T 564.1-2008 Calcium silicate board processing industry standard). The test results are summarized in Table 1.

Here, the directions in Table 1 refer to the production line flow direction (that is, the direction in which the belt conveyor flows) as the "vertical direction," and the direction perpendicular to this longitudinal direction as the "lateral direction." Loads are applied along the horizontal direction. The case where the load is applied along the vertical direction is defined as the ``horizontal direction'', and the case where the load is applied along the vertical direction is defined as the ``vertical direction''.

As shown in Table 1, the average impact strength in the transverse direction was 3.22 (KJ/m ² ), which was higher than the average value in the longitudinal direction of 1.90 (KJ/m ² ). The average value of the length and width was 2.56 (KJ/m ² ).

Next, the bending strength test was conducted using a three-point bending method in which both ends of the sample were supported and a load was applied to the center. The bending strength R was calculated using the formula R=3PL/ ^2be2 . Here, P is the maximum load (N) when the water absorbent board breaks, L is the distance between supporting points (mm), b is the side length of the square sample (mm), and e is the thickness of the square sample (mm). be.

The test results are summarized in Table 2. Here, the horizontal direction is the result of testing with the sample supported at both ends in the direction along the production line flow line, and the vertical direction is the result of the test with the sample supported at both ends in the direction perpendicular to the production line flow direction. This is the result of a test.

As shown in Table 2, the average bending strength in the transverse direction was 13.47 (N/mm ² ), which was higher than the average value in the longitudinal direction, 10.53 (N/mm ² ). The average value of the length and width was 12.00 (N/mm ² ).

In addition, a water-absorbing board was bent in which the mixing ratio of each raw material P was 30 wt% to 50 wt% of glass foam material, 5 wt% to 15 wt% of silica sand, 15 wt% to 35 wt% of slaked lime, and 20 wt% to 35 wt% of pulp. When the strength was also measured, the bending strength R was in the range of 9 to 12 (N/mm ² ). Considering that the bending strength R of a bath mat made of general diatomaceous earth is approximately 8 to 10 (N/mm ² ), it was confirmed that the bath mat has a bending strength that can withstand even when a human body weight is applied as a load. . It was also found that when the total content of the glass foam material and silica sand exceeds 70 wt%, the strength decreases.

Next, a water absorption performance test of the water absorbent board was conducted. In this test, the sample was placed in a tank filled with water, immersed until completely submerged, and left until no air bubbles appeared (saturated state where no water was absorbed).The difference between the weight before and after immersion was determined by The water absorption rate was calculated. The test results are shown in Table 3.

As shown in Table 3, the water absorption rate of the water absorbent board in Example 1 is about 50%, and considering that the water absorption rate of the glass foam material used as the raw material is about 20%, it can be used as a board as is. We were able to obtain higher water absorption performance.

Next, in Example 1, the water absorbent board according to the present invention was cut into the size of a bath mat using an electric saw, and the surface was polished using a sand machine to process it into a bath mat. FIG. 4 is a photographic image of a water absorbent board processed into a bath mat. As shown in FIG. 4, the water-absorbing board could be cut into a predetermined size without chipping the corners of the board. In addition, by polishing the surface, we were able to eliminate the roughness and create a smooth surface.

Next, in Example 2, water-absorbent boards were manufactured by the method for manufacturing water-absorbent boards according to the present invention by changing the blending ratios of glass foam material, silica sand, slaked lime, and pulp, and each sample (water-absorbent board) was Additional tests were conducted for density, water absorption, water absorption rate, and bending strength. The density was calculated by measuring the weight (mass) of the sample and dividing it by the volume of the sample. The sample at this time had a square shape with a side of 10 cm and a cubic shape with a thickness of 0.9 cm. In addition, the water absorption rate was defined as the time required to drop a water droplet onto the sample and until it was completely absorbed. The water absorption rate was measured visually and with a stopwatch. The same test method as in Example 1 was used for water absorption and bending strength.

Table 4 summarizes the blending ratio of each raw material and the test results.

As shown in Table 4, there are five blending ratios (component ratios) of each raw material when producing the water absorbent board in Example 2: blending ratio 1 to blending ratio 5. Regarding the glass foam material, the blending ratio was increased in the order of blending ratio 1 to blending ratio 5. On the other hand, the blending ratios of silica sand, slaked lime, and pulp were decreased in the order of blending ratio 1 to blending ratio 5.

In addition, five samples (N1 to N5) were produced for each blending ratio, and the density, water absorption rate, water absorption rate, and bending strength of each sample were measured. In addition, the average value of each measurement value was calculated.

As a result, the average values of density and bending strength decreased as the proportion of glass foam material increased (or as the proportion of silica sand decreased). Considering that the bending strength R of bath mats using general diatomaceous earth is about 8 to 10 (MPa (N/mm ² )), the blending ratio may exceed 50wt% or the blending ratio of silica sand may be less than 5wt%. It turned out that the strength was lower than that of a typical diatomaceous earth bath mat, which was not desirable.

On the other hand, it was found that when the blending ratio of glass foam material was decreased and the ratio of silica sand, slaked lime, and pulp was increased, the bending strength increased, but the water absorption rate and water absorption rate decreased. In particular, in blending ratio 1 and blending ratio 2 in which the blending ratio of the glass foam material was less than 30 wt%, the water absorption rate significantly decreased to about 30% or less. On the other hand, for blending ratios 3 to 5 in which the blending ratio of the glass foam material was 30 wt% or more, the water absorption rate was 40% or more. In other words, it was found that increasing the blending ratio of slaked lime and pulp increases the bending strength, but when increasing the blending ratio beyond 35 wt% of blending ratio 1, the water absorption rate becomes 26% or less, which is not preferable.

Based on the above, the blending ratio of the glass foam material is preferably in the range of 30 wt% to 50 wt%, considering water absorption rate, bending strength, etc., and taking into consideration water absorption rate, bending strength, and efficiency of the manufacturing process. It has been found that it is preferable to specify the blending ratios of silica sand, slaked lime, and pulp.

Note that the water absorbent board and the method for manufacturing the same according to the present invention are not limited to the embodiments described above, and can be modified as appropriate. For example, the product processed in the product processing step S7 is not limited to a board-like product, and may be used for various products that require water absorption. Furthermore, as described above, the stacking step S4 in the method for producing water absorbent boards according to the present invention is performed in order to increase the production efficiency related to solidification by increasing the number of boards that can be put into the autoclave 8 at one time in the solidifying step S5. Even if the process does not include this process, other processes (S1 to S3, S5) can suppress yield, increase strength, ensure high water absorption, and contribute to the realization of a sustainable society. effect can be obtained.

1 Water absorbent board 2 Mixer 3 Belt conveyor 4 Roller 5 Dryer 51 Drying conveyance path 52 Conveyor 53 Exhaust port 6 Cart 7 Metal pad 71 Ventilation port 8 Autoclape 9 Cutting machine P Raw material W Water M Fabric

Claims (4)

Manufacture of a water-absorbent board containing a glass foam material with water-absorbing properties obtained by heating and firing a mixed powder obtained by adding silicon carbide to a glassy compound powder obtained by crushing glassy waste material above the softening point of glass . The method includes silica sand, slaked lime, and pulp together with the glass foam material, and the blending ratio of raw material components in the manufacturing process is 30 wt% to 50 wt% of the glass foam material, 5 wt% to 15 wt% of the silica sand, The method for producing the water-absorbent board , including the step of setting the slaked lime at 15 wt% to 35 wt% and the pulp at 20 wt% to 35 wt% . Manufactures a water-absorbing board containing a glass foam material with water-absorbing properties obtained by heating and firing a mixed powder obtained by crushing glassy waste material and adding silicon carbide to a temperature above the softening point of glass. A method of
The mixing ratio of the powdered glass foam material, silica sand, slaked lime, and pulp is 30 wt% to 50 wt% of the glass foam material, 5 wt% to 15 wt% of the silica sand, 15 wt% to 35 wt% of the slaked lime, and 20 wt% of the pulp. A dough making process in which the mixture is mixed with water to create a slurry-like dough at ~35wt% ;
a plate-shaped dough forming step of forming the slurry-like dough into a plate shape of a predetermined thickness;
A first drying step of drying the dough formed into a plate shape while heating it until the moisture content becomes 40% or less;
A solidifying step of heating the dough, which has been dried to a moisture content of 40% or less, at a temperature of 180° C. for 24 to 48 hours in an environment of atmospheric pressure or higher and a maximum pressure of 1 Mpa or lower to solidify it;
a second drying step of drying the solidified plate-shaped fabric to a moisture content of 15% or less while heating it at a higher temperature than the first drying step. According to claim 2, in the first drying step, the dough is heated within a temperature range of 30° C. to 50° C., and in the second drying step, the dough is heated within a temperature range of 90° C. to 100° C. The method of manufacturing the water absorbent board described. Between the first drying step and the solidifying step, the plurality of fabrics dried in the first drying process are stacked vertically, and each predetermined number of fabrics is made of metal having a ventilation hole penetrating in the vertical direction. The method for manufacturing a water absorbent board according to claim 2 or 3 , comprising a stacking step of arranging the pads.

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