JP2801493B2 - Manufacturing method of inorganic building board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing an inorganic building board used for a foundation of a wall or the like, and more particularly, to a method of manufacturing an inorganic building board having substantially the same performance as gypsum board and being lighter than a gypsum board.

[0002]

2. Description of the Related Art In general, a base material is required to have nail holding power, bending strength, impact strength, fire resistance, water / moisture resistance, cutability and the like which are not less than a certain value. For this reason, gypsum boards have conventionally been used. However, gypsum boards have a specific gravity of 0.74 or more and require a certain thickness in terms of bending strength. It is too inconvenient for transportation and construction. Further, the gypsum board has paper on the front and back surfaces, and when the paper is peeled, there is a problem that strength, water resistance and the like are significantly reduced.

[0003] For this reason, in order to solve the above-mentioned problems, for example, a method of manufacturing an inorganic building board described in Japanese Patent Application No. 3-207895 has been considered. In particular, in the step of pressing and integrating the laminate, the air between the particles is extruded and brought into close contact with each other, and a part of the particles in the middle layer is cut into the wet inorganic plates in the upper and lower layers by pressing to form the lower layer. Department,
The middle part and the upper part are integrated.

[0004]

However, the mixture for the middle layer contains an inorganic foam, a fibrous material, and a binder as essential components, and a small amount of water is used to prevent scattering during mixing. And does not have enough moisture to activate the binder. For this reason, even if the laminate is heated at the time of pressing by a roll press or the like, the binder in the middle layer is not sufficiently activated, and the mixture in the middle layer is likely to form a so-called spring bag immediately after decompression.
As a result, even when the binder of the mixture is activated by steam generated from the upper and lower layers by subsequent heating, the dimensional accuracy of the final product is low because the laminate is deformed by springback. In addition, in the above-described manufacturing method, only the upper and lower layers are heated due to the short heating time, and the middle layer is intact. However, there is a problem that the size of the heating dryer is increased.

In view of the above problems, the present invention provides an inorganic material which has almost the same performance as gypsum board, is lighter than gypsum board, has a desired dimensional accuracy, and can be manufactured by a small-sized manufacturing apparatus. An object of the present invention is to provide a method for manufacturing a building board.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention comprises a step of forming a wet inorganic plate as a lower layer from a slurry containing mineral fibers, an inorganic powder and a binder as essential components. Forming a mixture layer serving as a middle layer by spraying and depositing a mixture for the middle layer containing an inorganic foam, a fibrous material, and a binder as essential components on the wet inorganic plate at a uniform thickness; A step of laminating a wet inorganic plate as an upper layer obtained by papermaking from a slurry containing fibers, an inorganic powder and a binder as essential components to obtain a laminate by laminating the mixture layer;
Heating and pressing the laminate to activate the binder of the mixture layer with the vapor generated from the upper and lower layers to integrate the middle layer of the mixture layer into the upper and lower layers. Manufacturing method.

The mineral fibers forming the lower layer include, for example, rock wool, slag wool, mineral wool,
Glass fiber and the like can be mentioned, and these alone,
Alternatively, two or more kinds can be used in combination. And
The composition ratio of mineral fibers in the lower layer is 20 to 45% by weight.
It is preferred that If the content is less than 20% by weight, the inorganic powder described below cannot be held, and the bending strength is low. If the content is more than 45% by weight, the amount of the inorganic powder added becomes small, and the surface hardness is reduced. And the overall hardness cannot be increased.

The inorganic powder forming the lower layer is used to increase the hardness and to increase the screwing performance while maintaining fire resistance. For example, calcium carbonate, silica sand, micro silica, slag, aluminum hydroxide And the like. The composition ratio of the inorganic powder in the lower layer portion is
Preferably it is 40 to 70% by weight. If the content is less than 40% by weight, the desired surface hardness cannot be obtained.
If the content is more than 0% by weight, drainage is reduced, so that papermaking becomes difficult. In addition, when the particle size of the inorganic powder is about 150 μm, the strength of the lower layer portion is the largest, but the average particle size may be 40 μm to 300 μm.

The binder forming the lower layer is for linking and integrating the mineral fiber and the inorganic powder.
For example, synthetic resins such as melamine resin and phenol resin, starch and the like can be mentioned, and these can be used alone or in combination of two or more.

Further, the slurry for forming the lower layer portion includes:
In addition to the binder, pulp, synthetic fiber, sizing agent, fixing agent and the like are added as required.

In general, the more organic fibers, the better the bending strength. Therefore, it is effective in terms of strength to mix organic fibers such as pulp into a part of the mineral fibers constituting the lower layer. It is also effective in terms of cost. However, in order to obtain an inorganic building board as a quasi-noncombustible material, the total amount of organic components in the lower layer portion needs to be 15% by weight or less. Also, in order to obtain an inorganic building board as a noncombustible material, the total amount of organic components must be reduced to 7% by weight or less. Therefore, the total amount of the binder is regulated, and a larger amount of mineral fibers than the semi-combustible material is used. It needs to be added.

The slurry for forming the wet inorganic plate serving as the lower layer is obtained by putting the mineral fibers, inorganic powder, binder and the like into water, stirring and uniformly dispersing. Then, a wet inorganic plate to be a lower layer is formed from the slurry by a papermaking machine.

[0013] The papermaking method can be arbitrarily selected from existing methods, for example, a fourdrinier papermaking method capable of high-speed papermaking,
A round-mesh paper-making method is suitable, in which the fibers are well entangled and a high-strength wet inorganic plate is obtained.

The inorganic foam of the mixture forming the middle layer is intended to reduce the weight while maintaining the compressive strength. Examples thereof include pearlite, shirasu foam, silica flower, glass foam and the like. They can be used alone or in combination of two or more. The composition ratio of the inorganic foam in the middle layer is preferably set to 50 to 90% by weight. If the amount is less than 50% by weight, the strength of the fibrous material is improved because the proportion of the fibrous material is relatively increased, but the effect of lowering the specific gravity cannot be obtained. This is because the ratio becomes small and the connection between the inorganic foams becomes insufficient.

The fibrous material of the mixture forming the middle layer is for connecting the inorganic foams to each other.
Rock wool, slag wool, pulp, polypropylene fiber and the like can be mentioned, and these can be used alone or in combination of two or more. The fibrous material is for connecting the inorganic foam to form a plate,
At least 3% by weight or more is added, but if it is too much, the amount of the inorganic foam to be added becomes relatively small and the weight cannot be reduced.

The binder of the mixture forming the middle layer is for linking and integrating the inorganic foam and the fibrous material, and examples thereof include synthetic resins such as melamine resin and phenol resin, and starch. These can be used alone or in combination of two or more.

In order to obtain an inorganic building board as a quasi-noncombustible material, the total amount of organic components must be 15% by weight or less. For this reason, when organic fibers such as pulp are used in place of the mineral fibers also in the middle layer, it is necessary to take care that the total amount of the organic components including the binder is within the above-mentioned range. In addition, in order to obtain an inorganic building board as a noncombustible material, the total amount of organic components must be 7 as in the case of the lower layer described above.
Weight percent or less. Therefore, it is necessary to add a larger amount of inorganic fibers than the semi-combustible material.

The mixture for the middle layer may be a mixture obtained by simply mixing the inorganic foam, fibrous material, binder and the like. However, the mixture is sprayed with water to prevent scattering and the like, so that the mixture is appropriately moistened. It may be what you have. The mixture for the middle layer is sprayed and deposited with a uniform thickness on the upper surface of the wet inorganic plate to form a mixture layer.

Next, the wet inorganic plate serving as the upper layer portion is obtained through the same operation as the above-described wet inorganic plate serving as the lower layer portion.
The composition, thickness and the like may be varied as needed. Then, a laminate is obtained by laminating a wet inorganic plate to be an upper layer on the upper surface of the mixture for the middle layer deposited on the lower layer.

In the step of heating and pressing the laminate to integrate it, the air between the particles of the mixture layer is pushed out by pressing, while a part of the particles are bitten into the wet inorganic plate, and The lower layer, the middle layer, and the upper layer are brought into close contact by simultaneously supplying moisture and heat to the mixture layer serving as the middle layer with the steam generated from the wet inorganic plates in the upper and lower layers due to the heating of the binder and activating the binder. This is the step of integrating.

The heating temperature and pressure can be appropriately selected according to the required strength of the inorganic building board, the thickness of each layer, the composition, and the like.
Although it is difficult to limit the temperature uniquely, generally, the heating temperature is preferably from 120 to 220C, particularly preferably from 170 to 200C. When the temperature is lower than 120 ° C., it takes a long time to activate the binder in the middle layer, and the productivity is greatly reduced.
If the temperature exceeds 220 ° C., it is necessary to consider thermal deformation of the equipment. The pressure is 5 to 20 kg / cm ² , especially 7
８8 kg / cm ² is preferred. If it is less than 5 kg / cm ² , sufficient strength will not be obtained, and if it exceeds 20 kg / cm ² , the whole will have high density.

Since the foam layer occupies a large part of the volume of the mixture layer serving as the middle layer of the present invention, the heat transfer coefficient is generally low. However, according to the production method of the present invention, when the middle layer does not contain appropriate water, However, moisture and heat are simultaneously supplied to the mixture layer serving as the middle layer by the water vapor generated from the wet inorganic plates in the upper and lower layers, and the binder in the middle layer is activated and adhered and integrated. For this reason, the present invention has the advantage that the drying time and the drying cost can be greatly reduced and the drying apparatus can be reduced in size, as compared with a method in which all the layers are manufactured in a wet process and then the respective layers are closely adhered and integrated. .

In order to activate the binder in the middle layer, heating and pressurizing for several seconds are required. In particular, when the heating temperature is low, it takes several tens of seconds for the binder in the middle layer to be activated, but when the temperature is high, the middle layer is activated in a few seconds.

[0024]

【Example】

(Example) 30 parts by weight of rock wool as a mineral fiber,
50 parts by weight of calcium carbonate as an inorganic powder, 5 parts by weight of aluminum hydroxide, 7 parts by weight of a mixture of powdered phenol and starch, 7 parts by weight of pulp, and a small amount of a sizing agent, a flocculant, etc. in clear water as a binder. Charge, stir,
An aqueous slurry having a concentration of 2% was obtained. Then, as shown in FIG. 1, the aqueous slurry was introduced into fourdrinier paper machines 1 and 4,
Wet inorganic plates 2 and 5 serving as lower and upper layers of 3 mm in thickness
Was prepared.

On the other hand, 30 parts by weight of perlite as an inorganic foam, 30 parts by weight of shirasu foam, 5 parts by weight of aluminum hydroxide as an inorganic powder, 20 parts by weight of rock wool and 5 parts by weight of pulp as a fibrous material, 10 parts by weight of a mixture of powdered phenol and starch as a binder,
These were uniformly mixed while spraying 40 parts by weight of fresh water to obtain a mixture for the middle layer.

Next, the mixture for the middle layer was uniformly sprayed on the wet inorganic plate 2 having a thickness of 3 mm obtained by the fourdrinier machine 1 so as to have a thickness of 28 mm to form a mixture layer 3. Then, a 3 mm-thick wet inorganic plate 5 obtained by a fourdrinier machine 4 was laminated thereon to obtain a laminate 6 having a total thickness of 34 mm. Then, the laminate 6 is fed to a continuous belt press 7 heated to 180 ° C., pressed under a pressure of 5 kg / cm ² for 20 seconds, and decompressed. An inorganic building board 8 was obtained. Then, after being cut into an appropriate length by the cutter 9, it was sent to a dryer 10 at a temperature of 180 ° C. to obtain a dried inorganic building board 11, which was used as a sample.

As can be seen from FIG. 2 showing the temperature changes of the middle layer and the upper layer during heating and pressing, the temperature of the middle layer rapidly increases as the temperature of the upper layer increases in the initial stage of heating. Recognize. It should be noted that the temperature of the upper layer portion 5 sharply dropped about 4 seconds after heating and pressing.
It is considered that this is because the steam filled in the middle layer leaks from the middle layer to the outside air, and the internal pressure in the plate decreases. However, the middle layer maintains a temperature of around 80 ° C., which is sufficient to activate the binder in the middle layer.

Comparative Example A commercially available gypsum board was used as a sample.

Test Examples The results of quality tests performed on the samples of the inorganic building boards obtained in the examples and commercially available gypsum boards are shown below. Example Comparative example Dimensions (mm) 910 × 1820 910 × 1820 Thickness (mm) 9 9 Specific gravity 0.43 0.74 Weight per sheet (kg) 6.4 11.0 Bending strength (kgf / cm ² ) 75 50 Surface Hardness (kgf) 170 250 Visibility Penetration (kgf) 18 30 Fire protection Semi-combustible pass Semi-combustible pass

The test results were obtained based on the following method. Flexural strength: based on JIS 5907-1977. Surface strength: Based on JIS HARDNESS TESTER. Screw penetration force: Based on a test method according to JIS A5910. Fire protection: Based on JIS A1321.

As is apparent from the above measurement results, the specific gravity of the example is 40% or less than that of the comparative example. Specific gravity is 4
The fact that it is smaller than 0% means that when the standard size gypsum board is about 11 kg, the inorganic building board of the present invention of the same size is about 6.5 kg. For this reason, in the case of a gypsum board, even when only about half of the loadable capacity of a truck or the like is available due to weight restrictions, the inorganic building board of the present application can load the full loadable capacity of a truck or the like. As a result, not only can logistics costs be significantly reduced, but also manual transportation and assembly work to the construction site is facilitated. Further, since the bending strength of the example was 50% or more higher than that of the comparative example, it was found that it was difficult to be deformed and the usability was good.

In the examples, although the surface hardness and the screw penetration force are smaller than those of the comparative example, the surface hardness is generally 1 unit.
If it is 50 (kgf), dents and the like hardly occur, and there is no practical problem. Further, the screw penetration force is required to be at least 2.5 times the weight of the inorganic building board. However, since the inorganic building board according to the present invention itself is lightweight, there is no practical problem in this respect. Therefore, the inorganic building board according to the present application can be used almost equally with a commercial gypsum board,
It was found to be over 40% lighter than a commercial gypsum board.

[0033]

As is clear from the above description, according to the method for manufacturing an inorganic building board according to the present invention, a lightweight middle layer is sandwiched between a hard and dense upper layer and a lower layer. An inorganic building board will be obtained. Therefore, according to the present invention, an inorganic building board having substantially the same performance as gypsum board and lighter than gypsum board can be obtained. In particular, even if the middle layer is formed by a dry method, the air between the particles is pushed out and adhered by the pressing, and a part of the particles dig into the wet inorganic plate of the upper and lower layers, and the heating and pressing of the upper and lower layers are performed. Since the steam generated from the upper and lower layers by tightening activates the binder of the mixture layer which is the middle layer,
The whole is more closely integrated. Moreover, since the middle layer is manufactured by a dry method, the drying time and the drying cost can be reduced and the apparatus can be downsized compared to a case where all the layers are manufactured by a wet method. In particular, since heating and pressing are performed simultaneously, the binder in the middle layer is activated, and cutting and transporting before drying can be performed. For this reason, a multi-stage drying device can be used, etc.
There is an effect that the manufacturing apparatus can be further downsized.

[Brief description of the drawings]

FIG. 1 is a process chart showing a manufacturing method according to an embodiment of the present invention.

FIG. 2 is a graph showing temperature changes in a middle layer and an upper layer in a manufacturing method according to one embodiment of the present invention.

[Explanation of symbols]

1,4 ... Fourdrinier machine, 2,5 ... wet inorganic plate, 3 ... mixture for middle part, 6 ... laminate, 7 ... continuous belt press, 8 ...
Continuous inorganic building board, 9 ... Cutter, 10 ... Dryer, 1
1. Inorganic building board.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-55-139205 (JP, A) JP-A-4-125106 (JP, A) JP-A-53-25623 (JP, A) JP-A-50-139 138616 (JP, A) JP-A-5-50417 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B28B 1/52 B28B 1/16

Claims (3)

(57) [Claims] 1. A step of forming a wet inorganic plate as a lower layer from a slurry containing mineral fibers, an inorganic powder and a binder as essential components, and an inorganic foam, a fibrous material and a binder as essential components. Dispersing and depositing the mixture for the middle part to a uniform thickness on the wet inorganic plate to form a mixture layer serving as the middle part, and a slurry containing mineral fibers, inorganic powder and a binder as essential components. A step of laminating a wet inorganic plate as an upper layer portion obtained by papermaking from the mixture layer to obtain a laminate, heating and pressing the laminate, and forming a mixture layer with steam generated from the upper and lower layer portions. Activating the binder to integrate the middle layer comprising the mixture layer into the upper and lower layers. 2. The method for producing an inorganic building board according to claim 1, wherein the wet inorganic board is formed by a fourdrinier machine. 3. The method for producing an inorganic building board according to claim 1, wherein the wet inorganic board is formed by a circular net type paper making machine.