JPH07329236A - High strength gypsum board and method of manufacturing the same - Google Patents

Abstract

PURPOSE:To obtain a lightweight high strength gypsum panel having high rigidity and excellent in impact resistance by laminating a reinforcing layer composed of a thermoplastic resin panel compounded with a fiber in specific wt. content to the single surface or both surfaces of a gypsum panel. CONSTITUTION:A laminate 10 is obtained by laminating prepreg laminates 14, 15 on both upper and rear surfaces of a gypsum panel 11 and bonding a thin sheet like surface material 16 to the surface of the upper prepreg laminate 15 if necessary. The material resin of the laminates 14, 15 and the surface material is desirably the same resin. As the fiber compounded with the material of the laminates 14, 15, a synthetic resin fiber, a metal fiber and an inorg. fiber are designated. When the compounding ratio of the fiber becomes below 40% in a wt. ratio, since the flowability of the resin is increased at high temp., the shaping of the prepreg laminates becomes difficult and rigidity and abrasion resistance necessary as a panel are not obtained and, when the compounding ratio exceeds 80% contrarily, adhesiveness lowers and molding processing becomes difficult and, therefore, the compounding ratio of the fiber is set to 40-80%, desirably, 45-60%.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plate-shaped product for civil engineering and general industry, and particularly to a plate requiring strength.

[0002]

2. Description of the Related Art Gypsum boards are widely used for building ceilings and walls of houses. However, it is heavy and fragile and requires careful handling. As one method for solving these problems, there has been proposed a method in which a glass fiber mat or a glass fiber woven cloth impregnated with a thermosetting resin is attached to a plaster board. However, such a base material has a poor fiber impregnation with a thermosetting resin when it is attempted to have a high strength by increasing the fiber content, and it is difficult to make it thin, and there is a limit to the increase in weight and strength. Further, since it is a thermosetting resin, it is necessary to apply pressure at a high temperature for a long time in order to bond it to the gypsum board, and there is a high possibility that the gypsum board will deteriorate due to heat. further,
It is difficult to prevent warpage due to curing shrinkage of the thermosetting resin. Therefore, at present, a gypsum board that is light, has high rigidity, high strength, impact resistance and is easy to handle in the field has not been proposed yet.

[0003]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and its purpose is to be lighter than conventional materials alone, to use a small amount of raw materials, to be lightweight, to have high rigidity, It is intended to provide a high-strength gypsum board that has high strength, excellent impact resistance, is easy to handle, and is highly water resistant and durable.

[0004]

In order to solve the above problems, the present inventors have made a reinforcing layer made of a thermoplastic resin in which a fiber having a weight content of 40 to 80% is mixed on one or both sides of a plaster board. It has been found to be achieved by laminating.

The resin constituting the reinforcing layer is preferably a thermoplastic resin, more preferably a polypropylene resin or a polystyrene resin. As the fiber to be mixed in the reinforcing layer, glass fiber is preferable. As the form of the glass fiber, a mat-like or woven fabric-like one is generally easy to handle and is generally used, but it is necessary to effectively utilize the strength of the fiber in order to sufficiently exert its reinforcing effect with a light weight. For that purpose, it is desirable to use fibers in which fibers are aligned and arranged in one direction. Further, it is recommended that a sheet-like surface material made of, for example, embossed resin be provided on the surface of the reinforcing layer on the surface side.

An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a perspective view showing an embodiment of a high-strength gypsum board according to the present invention, which shows a thermoplastic resin board in which fibers are mixed on the surface of the gypsum board, that is, a high-strength gypsum board on which a prepreg is laminated. . FIG. 2 shows a high-strength gypsum board with a surface material attached thereto. FIG. 3 shows an outline of an apparatus for integrating a prepreg laminate and a gypsum board.

1A of FIG. 1 is a flat plate suitably used for a wall or the like, and is composed of a lower paper 12 on the surface of a plaster board 11 and glass fibers aligned in one direction with a thermoplastic resin. The laminated body 14 of the directional prepreg is laminated. The lamination of the lower paper of the gypsum board and the prepreg laminate is carried out by placing the prepreg in a molten state by being heated to the melting temperature of the prepreg or above on the gypsum board and pressing it in the press with 0.0.
Pressure of 1-5 kg / cm ² , preferably 0.1-3 kg
It is achieved by pressurizing while cooling at / cm ² . Pressure becomes poor adhesion to the lower than 0.01 kg / cm ² and lower sheet of the prepreg and plaster plates, 5 kg / cm ²
If it exceeds, there is a problem that the gypsum board is crushed and becomes thinner than the specified thickness.

At this time, the melted thermoplastic resin of the prepreg flows to the uneven portion of the lower paper on the surface of the gypsum board and is then cooled and solidified, so that the gypsum board and the prepreg laminate are firmly bonded. Therefore, it is an effective method to preheat the gypsum board to a temperature at which the resin can flow so that the resin flows to the gypsum board and the irregularities are filled. Further, the resin film is previously fused to the surface of the lower paper of the gypsum board to make the resin film bite into the uneven portions of the paper on the surface of the gypsum board, so that the gypsum board and the prepreg laminate are firmly bonded. Desirable for laminating.

Such a resin film is a film made of the same kind of thermoplastic resin as the thermoplastic resin plate in which fibers are mixed, and it is preferable that it is not stretched because it does not shrink due to heat. The thickness of the resin film is preferably 10 to 200 μm because the amount of resin that allows the lower paper of the gypsum plate and the thermoplastic resin plate containing the fibers to be sufficiently adhered is required. Further, interposing a resin film between the prepreg laminate in a molten state and the gypsum board to perform simultaneous integral molding is also an effective method for firmly integrating the reinforcing layer and the gypsum board. As described above, the prepreg laminate is firmly attached to the surface of the gypsum board without using an adhesive, so that a reinforcing effect can be obtained. 1B of FIG. 1 is a plaster board 1
The prepreg laminates 15 and 14 are attached to the upper paper 13 and the lower paper 12 on both front and back sides of the No. 1 sheet. In addition, since the plaster board is broken from the cut end surface or the reinforcing layer is peeled off, a reinforcing layer slightly smaller than the area of the plaster board is attached as shown in FIG. 1C, or the end surface is shown as shown in FIG. 1D. Is preferably coated with a reinforcing layer in terms of end face protection. By doing so, the reinforcing layer is not peeled off from the end portion and the handleability is improved. Further, covering the end face portion with a surface material is also effective as a measure for preventing peeling.

In the laminated body 10 of FIG. 2, prepreg laminated bodies 14 and 15 are laminated on both front and back surfaces of a gypsum board 11, and if necessary, a thin sheet-like surface material 16 is formed on the surface of the reinforcing layer 15 on the front side. It is made by pasting. The surface material used in the present invention is used for improving the surface condition of the reinforcing layer and adding a new function, and as its material, thermosetting resin such as polyimide and polyethylene, polypropylene, polychlorinated Films and sheets of thermoplastic resin such as vinyl, polyethylene terephthalate fiber, non-woven fabric made of synthetic fiber such as rayon, inorganic fiber such as glass fiber, woven fabric made of organic fiber such as cotton, polypropylene,
Examples thereof include heat-shrinkable films made of thermoplastic resin such as polyvinyl chloride, paper, natural resources such as wood-based thin layer boards, and the like.
Furthermore, those obtained by printing or embossing these surface materials can also be used as the surface material.

For example, the surface material 14 is used as a material for improving the releasability from concrete when used in a concrete formwork, for smoothing the surface of the cast concrete, for glossing, etc. Examples thereof include films and sheets of thermoplastic resin such as polypropylene. Furthermore,
In order to enhance the aesthetic appearance of the outer surface of the structure, it is also recommended to use embossed surface material 14 to transfer various patterns such as wood grain, stone grain, brush grain and line drawing to the concrete placing surface. It is what is done. When it is used for interior walls, partitions, etc., a non-woven fabric or woven fabric on which a pattern is printed, a printing paper on which a pattern such as wood grain is printed, a wood-based thin plate, etc. can be used as the surface material. Further, when used outdoors, a resin film or equipment having excellent weather resistance can be used for the purpose of imparting weather resistance.

If an adhesive is applied to the surface of such a thermoplastic resin to join a surface material for decoration, the thermoplastic resin has a poor surface activity, and the effect of the adhesive is reduced. Therefore, sanding the surface of the reinforcing layer, pretreatment such as corona discharge treatment, chemical etching, etc. are required, which causes an increase in cost. To solve this problem, thick paper, non-woven fabric or the like is first fused as an auxiliary material for improving the adhesive strength of the adhesive when the gypsum board and the reinforcing layer are integrated on the surface of the reinforcing layer opposite to the gypsum board. Since the paper and non-woven fabric attached here have a function of impregnating and holding an adhesive, a surface material for decoration can be joined by adhesion.
The gypsum board that can be used in the present invention includes a gypsum board, JIS G6901, gypsum board, reinforced gypsum board, gypsum lath board, and decorative gypsum board.

Next, the structure and manufacturing method of the high strength gypsum board 10 will be described. There is no particular limitation on the thermoplastic resin that constitutes the prepreg laminates 14 and 15, and the melting temperature at which the paper on the surface of the gypsum board does not burn and the gypsum board does not deteriorate at the temperature when integrated with the gypsum board. With, for example, polystyrene, polyvinyl chloride, high density polyethylene, polypropylene, polycarbonate, polybutylene terephthalate, polyretylene terephthalate, polyether sulfone, polysulfone, polyetherimide (trademark: ULTEM), polyether Although ether ketone and polyphenylene sulfide can be used, polypropylene and polystyrene resins are recommended as the most desirable resins from the viewpoints of strength, abrasion resistance, price, and ease of recycling when they become waste. It It is desirable that the material resins of the prepreg laminates 14 and 15 and the surface material 16 are resins of the same system.

Examples of polypropylene resins include homopolymers of propylene, α of propylene and ethylene, butene, etc.
-In order to improve the adhesion between olefin copolymers and fibers and polypropylene resins, polypropylene resins are grafted with radically polymerizable unsaturated compounds such as maleic anhydride using an organic peroxide catalyst in a hydrocarbon solvent. An example is a polymerized grafted polypropylene resin.

As the polystyrene resin, a homopolymer of styrene, a copolymer of styrene and acrylonitrile, a polymer of butadiene and styrene, a polymer of acrylonitrile, and the like, and to improve adhesion to glass fiber,
Examples thereof include a grafted polystyrene resin obtained by graft polymerizing a radically polymerizable unsaturated compound such as maleic anhydride.

As the fibers to be added to the material of the prepreg laminates 14 and 15, synthetic resin fibers such as aramid fibers (registered trademark "Kepler"), natural organic fibers, titanium, boron, stainless steel, etc. Inorganic fibers such as metal fibers, glass, carbon and silicon carbide can be mentioned.
However, the material is not necessarily limited to these, and any material that has sufficient strength and is inexpensive and available in large quantities can be used.

Regarding the compounding ratio of this fiber, if it is less than 40% by weight, the fluidity of the resin increases at high temperatures, making it difficult to shape the prepreg laminate, and in addition, the rigidity and resistance required for the plate are high. If the abrasion resistance is not obtained and conversely exceeds 80%, the adhesiveness is deteriorated and the molding process becomes difficult. Therefore, the blending ratio of the fibers is 40% or more, 80% or less, preferably 45% or more, 60% or less.

It is also recommended that the fibers be aligned in a fixed direction, that is, in the direction in which they receive bending stress during use. It is also recommended to use this fiber-blended layer as a composite of a layer having fibers oriented in the width direction and a layer having fibers oriented in the longitudinal direction.

The prepreg can be manufactured by the method disclosed in Japanese Patent Publication No. 02-042168. That is, a thermoplastic resin obtained by treating a monofilament of reinforcing glass fiber with a coupling agent, for example, γ-methacryloxy-propyltrimethoxysilane and concentrating 1800 converged yarns while pulling them with uniform tension and heat-melting them. It is obtained by contacting with a resin and impregnating with a hot roll while squeezing. This prepreg may be used as a single layer or as a stack of two or more layers. When the prepreg is attached to one side of the plaster board, if the prepreg layer is thick or the coefficient of thermal expansion is large, There is a phenomenon that the composite plate warps.

Therefore, the thickness of one layer of prepreg is 200 μm.
3 m or less when the prepreg is laminated in two or more
It is preferably m or less. Furthermore, since the compound gypsum board warps when the prepreg has a large coefficient of thermal expansion, the coefficient of thermal expansion of the prepreg is preferably 10 ⁻⁵ / ° C. or less. The surface material 16 is made of foamed or non-foamed sheets such as polypropylene and polystyrene, thermoplastic resin products such as polyvinyl chloride and PZT sheets, metal foils, and woven and non-woven fabrics made of various fibers. , Those having fibers on the surface can be mentioned.

The method for producing these composite plates will be described below. A material sheet of a prepreg laminate composed of fibers and a thermoplastic resin is heated to a temperature equal to or higher than the melting temperature of the thermoplastic resin, laminated on both front and back surfaces of the gypsum board 11, and then pressed and shaped by a press roller or the like. According to the above, a desired surface material is attached to the surface to obtain a laminate.

As a method of integrating the prepreg laminate and the gypsum board by heat welding, the laminated prepreg is simultaneously heated to a melting temperature or higher, and if necessary, the gypsum board to a melting temperature of the resin constituting the prepreg or less, The prepreg and the laminated body are superposed, and are pressed and cooled at a pressure of 5 kg / cm ² or less in a press heated at room temperature to 80 ° C. to be integrated together to form a laminated body.

At this time, it is necessary to deaerate the air existing between the prepreg layers of the prepreg laminate, which is usually heated to a temperature not lower than the melting point of the resin constituting the prepreg to 5 kg / c.
Degas by pressurizing with a pressure of m ^{2 or} less. If the pressure is within this range, the gypsum board will not be crushed, so this degassing can be performed in the step of integrating with the gypsum board. As a matter of course, it is possible to use a laminated plate which is deaerated in advance and cooled.

The prepreg and the gypsum board can be heated without contacting the prepreg and the gypsum board, or can be heated while the prepreg is placed on the gypsum board and in contact with each other. At this time, when the high-temperature prepreg laminate sheet comes into contact with the surface of the gypsum board made of a resin foam, the molten resin flows in the irregularities on the surface of the gypsum board, and the melt is cooled and solidified. Then, the plaster board and the prepreg laminate are integrally bonded by biting into the uneven portion firmly.

The thermoplastic resin heated above the melting temperature is generally in a state where it can be melted and flowed, but the weight ratio is 40.
% Composite fibers, the resin is held in the lattice of fibers in a state in which it cannot flow freely, so that when pressure for shaping is applied in that state, the fibers are skeletonized. Since the overall shape is determined as a stable shape, a highly accurate molded product can be obtained.

Since the prepreg and the gypsum board must be integrated while the prepreg is in a molten state, it is necessary to devise a device so that the step of heating can be changed to the step of integrating in a short time. Is. As an example of such a device, as shown in FIG. 3, a press for integrating a prepreg and a gypsum board, and a preheating apparatus for a prepreg laminate and a gypsum board preheating apparatus equipped with a moving means for rapidly moving the material to the press. A combination of and is recommended. It is desirable to preheat the gypsum board in the range of 85 ° C to 95 ° C in the gypsum board preheating device, because the water of crystallization disappears and the crystal structure changes and the shape of the gypsum board cannot be maintained at a temperature of 100 ° C or higher. Further, the present invention will be described in detail with reference to specific examples.

[0027]

EXAMPLE The prepreg used in this example is of Japanese Patent Publication No.
It was manufactured by the method disclosed in JP-A-2-042168. In the case of glass fiber, the surface of a monofilament with a thickness of 13μ is treated with γ-methacryloxy-propyltrimethoxysilane, and 1800 filaments are bundled into a twist-free yarn, which is pulled in one direction while pulling the yarn with uniform tension. The prepreg was manufactured by aligning and entwining the resin with the yarn and impregnating the yarn with the resin while ironing the resin with a hot roll. In the case of carbon fiber, without using a sizing agent, 12,000 tow collected monofilaments with a thickness of 7μ are aligned in one direction while pulling with a uniform tension, the resin is entangled with the yarn, and the resin is heated on a heat roll. The prepreg was manufactured by impregnating the yarn while squeezing. The prepreg manufactured in this manner has excellent adhesion between the fiber and the thermoplastic resin, and the fiber content can be changed according to the requirement of 30 to 90% by weight, and the thickness is 0.1 to 1.0 mm. However, the fiber content is 40-80% by weight, and it is desirable to use the fiber at a thickness of 0.1-0.6 mm. When the weight content of the fibers is 40% or less, the amount of the fibers is small and the strength is low, and when it is 80% or more, the amount of the resin is small and the adhesion between the fibers and the resin is lowered, and the strength is lowered, which is not preferable. Table 1 shows the constitution of prepregs manufactured for use in Examples and Comparative Examples of the present invention. Table 2 shows the properties of the gypsum board used in the present invention.

[Embodiment 1] A gypsum board N is set to 400 in the longitudinal direction.
A rectangular piece having a length of 300 mm in the mm width direction was prepared. In addition, the prepreg A has a length of 4 in the fiber direction.
One piece is cut into a length of 00 mm and a length of 300 mm in the direction perpendicular to the fiber, and similarly, a piece of a length of 300 mm is cut in the direction of the fiber and one piece is cut into a length of 400 mm in the direction perpendicular to the fiber, and the fiber directions of the two prepregs are orthogonal to each other. Thus, a two-layer laminated body was formed by stacking two sheets on top and bottom. Press type gypsum board preheating device 20 shown in FIG.
Is heated to 95 ° C., gypsum board N is charged, and 0.1 kg / cm ²
Preheat at pressure of 2 minutes.

At the same time, the press type prepreg laminate preheating device 40 shown in FIG. 3 is heated to 200 ° C., the prepreg laminate 14 described above is sandwiched between the release films 22, and 0.1
Preheat at a pressure of kg / cm ² for 2 minutes. After the preheating is completed, the pressures of the press type gypsum board preheating device 20 and the press type prepreg laminate preheating device 40 are released. The upper release film 22 is peeled off, and the prepreg laminate 13 is put into the integrated device 30 heated to 70 ° C. with the release film facing down. Then, the surface of the lower paper 12 of the gypsum board 21 is changed to the prepreg laminate 14.
So that they fit together. At this time, the fiber direction length is 400
The prepreg laminate was laminated on a gypsum board so that the surface of mm was the surface. Then tighten the integrated device to 0.1
After pressurizing with a pressure of kg / cm ² for 1 minute, the high-strength gypsum board was taken out. The above operation was repeated to form a total of two high-strength gypsum plates.

The high-strength gypsum board was weighed and converted into a weight per 1 m 2. Furthermore, a load was applied to one of the high-strength gypsum plates by the bending test method defined in JIS A6901, and the breaking load was measured. However, a breaking load test was conducted with the surface on which the prepregs were stuck facing down. The remaining composite gypsum board was subjected to an impact test according to JIS A1421. However, the supporting method is simply opposite sides, and the weight is 1042.
A spherical weight of g was used, and the weight drop height was 50 cm. The results are summarized in Table 3.

Example 2 A high-strength gypsum board was molded in the same manner as in Example 1 except that prepreg B was used, and the physical properties were evaluated in the same manner as in Example 1. The results are summarized in Table 3.

[Example 3] A high-strength gypsum board was molded in the same manner as in Example 1 except that prepreg C was used, and the physical properties were evaluated in the same manner as in Example 1. The results are summarized in Table 3.

Example 4 A high-strength gypsum board was molded in the same manner as in Example 1 except that prepreg D was used, and the physical properties were evaluated in the same manner as in Example 1. The results are summarized in Table 3.

Example 5 A high-strength gypsum board was molded in the same manner as in Example 1 except that prepreg E was used, and the physical properties were evaluated in the same manner as in Example 1. The results are summarized in Table 3.

[Embodiment 6]
A high-strength gypsum board was molded in the same manner as in Example 1 except that the gypsum board O was used, and the physical properties were evaluated in the same manner as in Example 1. The results are summarized in Table 3. [Example 7] A high-strength gypsum board was formed in the same manner as in Example 1 except that 0-degree prepreg A was used instead of the 2-degree laminate of prepreg A. Physical properties were evaluated in the same manner as in Example 1. The results are shown in Table 3.

Example 8 The same procedure as in Example 1 was carried out except that 0 ° prepreg A was used instead of the 0 ° and 90 ° two-layer laminate of prepreg A, and O was used as the gypsum board. A strength gypsum board was molded. Physical properties were evaluated in the same manner as in Example 1.

Example 9 A high-strength gypsum board was manufactured in the same manner as in Example 1. However, after the prepreg laminate 14 from which the upper release film 22 has been peeled off is placed on the plaster board 21 with the release film 22 facing upward, the release film is peeled off,
A non-woven fabric made of polyethylene terephthalate having a weight of 30 g per 1 m2 was placed on the prepreg laminate 12 as a surface material, and then the integrated device was tightened to 0.1 kg / cm2.
After pressurizing with the pressure of 1 minute for 1 minute, the high strength gypsum board was taken out. Next, apply an adhesive to the surface to which the non-woven fabric is attached,
A surface material for decoration, which is a thin plate having a wall nut thickness of 0.2 mm, is bonded by a slicer. By this method, a composite plate having a beautiful appearance was obtained. Physical properties were evaluated in the same manner as in Example 1. The results are shown in Table 3.

Comparative Example 1 A high-strength gypsum board was formed in the same manner as in Example 1 except that prepreg F was used, and the physical properties were evaluated in the same manner as in Example 1. The results are summarized in Table 3.

Comparative Example 2 A high-strength gypsum board was molded in the same manner as in Example 1 except that prepreg G was used, and the physical properties were evaluated in the same manner as in Example 1. The results are summarized in Table 3.

[Comparative Example 3] The physical properties of the gypsum board N were evaluated in the same manner as in Example 1. The results are shown in Table 3.

[Comparative Example 4] The physical properties of the gypsum board O were evaluated in the same manner as in Example 1. The results are shown in Table 3.

[0042]

[Table 1]

[0043]

[Table 2]

[0044]

[Table 3]

[0045]

EFFECTS OF THE INVENTION The high-strength gypsum board according to the present invention is lighter than conventional ones, easy to handle on site, requires a small amount of raw materials, and has a high compressive strength. The prepreg laminate made of a fiber reinforced synthetic resin having extremely high rigidity and tensile strength is formed on both front and back surfaces thereof, and the rigidity is high as a whole, and an extremely solid structure can be constructed during use.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of a high-strength gypsum board.

FIG. 2 is a cross-sectional view showing a structure of a high-strength gypsum board in which a surface material is attached to one surface of a laminate.

FIG. 3 is a schematic view showing a method for manufacturing a high-strength gypsum board by integrating a gypsum board and a prepreg laminate of a reinforcing layer.

FIG. 4 is a high-strength gypsum board whose end surface is covered with a reinforcing layer.

[Explanation of symbols]

 1 High-strength gypsum board 10 High-strength gypsum board with surface material 11 Gypsum board 12 Lower paper 13 Top paper 14 Prepreg laminate 15 Prepreg laminate 16 Surface material 20 Press type gypsum board preheating device 22 Release film 30 Press type Prepreg laminate preheating device 40 integrated device

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Claims (16)

[Claims] 1. A high-strength gypsum board, characterized in that a reinforcing layer made of a thermoplastic resin board mixed with fibers having a weight content of 40 to 80% is laminated on one surface or both front and back surfaces of the gypsum board. 2. The high-strength gypsum board according to claim 1, wherein the thermoplastic resin is a polypropylene-based or polystyrene-based resin. 3. The high-strength gypsum board according to claim 1, wherein the fiber is glass fiber. 4. The high-strength gypsum board according to claim 1, wherein the fibers are arranged in one direction. 5. The thermoplastic resin plate according to claim 1, wherein the thermoplastic resin plate has a coefficient of thermal expansion in the fiber direction of 10 ⁻⁵ / ° C. or less, and a plate obtained by laminating the resin plate alone or a plurality of the resin plates is used as a reinforcing layer. Strength gypsum board. 6. The high-strength gypsum board according to claim 1, wherein the reinforcing layer has a thickness of 3 mm or less. 7. A surface material is provided on the surface of the reinforcing layer.
The high-strength gypsum board according to [6]. 8. The high strength gypsum board according to claim 7, wherein the surface of the surface material is embossed. 9. The high-strength gypsum board according to claim 7, wherein the surface material is a resin film. 10. The surface material is a non-woven fabric according to claim 7 or 8.
The high-strength gypsum board described. 11. The high-strength gypsum board according to claim 7, wherein the surface material is a woven cloth. 12. The high-strength gypsum board according to claim 7, wherein the surface material is a heat-shrinkable film. 13. The high strength gypsum board according to claim 1, wherein the cut end surface of the gypsum board is covered with a reinforcing layer. 14. The high-strength gypsum board according to claim 1, wherein the cut end surface of the gypsum board is covered with a surface material. 15. A reinforcing layer made of a thermoplastic resin mixed with a fiber having a weight content of 40 to 80% is heated to a temperature not lower than the melting temperature of the thermoplastic resin, laminated on both front and back surfaces of the gypsum board, and then,
A method for producing a high-strength gypsum board, which is characterized by pressing and shaping with a press, a roller, or the like. 16. The method for producing a high strength gypsum board according to claim 16, wherein a surface material is attached to the surface of the gypsum board.