JPH079617A - Inorganic building board and manufacturing method thereof - Google Patents

Abstract

(57) [Abstract] [Purpose] An object is to provide an inorganic building board having good dimensional stability and excellent paintability without impairing lightness, and a method for producing the same. [Structure] An inorganic foam and an inorganic fiber are formed between a lower layer portion and an upper layer portion, which are outer layers formed by adding a binder, mainly composed of mineral fibers and fibrous fine particles composed of inorganic fibers. An inorganic building board, characterized in that a fibrous fine particle composed of is used as a main component, and a middle layer portion to which a binder is added is integrally formed in a layered form.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inorganic building board used as a ceiling material, a wall material and the like, and a method for manufacturing the same.

[0002]

2. Description of the Related Art Generally,
Inorganic building boards that meet the non-combustible or semi-incombustible standards used for ceiling materials, wall materials, etc.
Surface hardness and thermal conductivity are required, and from the standpoint of construction, it is required to be lightweight and capable of being screwed. Although gypsum board is widely used as such a material, it is difficult to obtain sufficient performance in terms of fire resistance, water resistance and light weight with the gypsum board. Therefore, in order to obtain a lightweight inorganic building board with excellent fire resistance and water resistance, mineral fibers and inorganic powder are formed on the front and back surfaces of the middle layer part, which is mainly composed of an inorganic foam and to which a binder is added. It has been proposed that the outer layer portions mainly composed of, and added with a binder are laminated and thermocompressively integrated (Japanese Patent Application No.
194182, 194183, 194184).

However, although the above-mentioned inorganic building board achieves weight reduction, it is insufficient in dimensional stability due to moisture absorption and desorption, and further, since an inorganic powder is used in the surface layer portion, it has a flat surface. However, there is a problem that the paintability is poor due to the lack of preciseness.

In view of the above-mentioned problems, it is an object of the present invention to provide an inorganic building board which has improved dimensional stability without impairing its lightness and has excellent paintability, and a method for producing the same.

[0005]

Means for Solving the Problems As a result of intensive studies for achieving the above-mentioned object, the present inventors have found that the addition of fibrous fine particles made of an inorganic fiber to the outer layer portion and the middle layer portion improves the strength and improves the compactness. Therefore, it was found that the dimensional stability and the coating property are improved, and the present invention was completed based on this finding. The inorganic building board according to the present invention,
A fibrous material consisting of an inorganic foam and an inorganic fiber between the lower layer part and the upper layer part, which are the outer layer part formed by adding a binder, which is composed mainly of mineral fibers and fibrous fine particles composed of inorganic fibers. The intermediate layer portion containing fine particles as a main component and a binder added thereto is formed into a layer and integrated. Further, the method for producing an inorganic building board according to the present invention, as a method for producing the inorganic building board, mainly comprises fibrous fine particles composed of a mineral fiber and an inorganic fiber, and from a slurry to which a binder is added. A step of forming a wet inorganic mat to be the lower layer part, and a fibrous fine particle composed of an inorganic foam and an inorganic fiber as a main component, and a mixture for a middle layer part to which a binder is added is uniformly formed on the wet inorganic mat. A wet inorganic mat as an upper layer obtained by paper-making from a slurry containing a mineral fiber and a fibrous fine particle composed of an inorganic fiber as a main component, and a binder added. It comprises a step of obtaining a layered product by laminating the layered product on the mixture for the intermediate layer part, and a step of integrating the layered product and then drying.

The mineral fibers forming the outer layer include, for example, rock wool, slag wool, mineral wool,
Glass fiber etc. can be mentioned, these are alone,
Alternatively, two or more kinds can be used in combination. further,
The composition ratio of mineral fibers in the outer layer is 20 to 60% by weight.
Is preferred. If it is less than 20% by weight, the bending strength is low, and the surface is easily broken during screw driving.
This is because if it exceeds 60% by weight, the addition amount of the fibrous fine particles is relatively reduced, and the surface hardness and overall strength cannot be increased.

The fibrous fine particles composed of inorganic fibers forming the outer layer portion are for improving dimensional stability and coating property by improving surface performance while maintaining fire resistance. Examples of the inorganic fibers include natural inorganic fibers such as xonotlite, wollastonite, and sepiolite, and synthetic inorganic fibers such as synthetic wollastonite. As the fibrous fine particles, for example, wollastonite having a fiber length of 300 μ, a fiber diameter of 6 μ, and an assect ratio of 50 (trade name: Daiken fiber night, type HG), or a fiber length of 400
μ, fiber diameter 13 μ, and asbestos ratio 30 wollastonite (trade name: Daiken fiber night, type RG). Further, the composition ratio of the fibrous fine particles in the outer layer portion is preferably 40 to 80% by weight. 40% by weight
If it is less than 80% by weight, the surface hardness becomes insufficient and desired coatability cannot be obtained. If it exceeds 80% by weight,
This is because the desired strength cannot be obtained because the proportion of the mineral fibers is relatively reduced. These fibrous fine particles are finer than the inorganic powdery material of the prior application example, and have a small apparent specific gravity and are bulky. Therefore, when the same weight is added and pressure integration is performed, the surface is formed densely. In addition, since it is fibrous, the dimensional stability can be improved by the mutual entanglement. In addition to this, the inorganic powders used in the prior application examples, such as calcium carbonate and microsilica, may be partially used.

The binder forming the outer layer portion is for binding and integrating the mineral fiber and the fibrous fine particles, and examples thereof include synthetic resins such as epoxy resin and starch, and these are independent. Alternatively, two or more kinds may be used in combination.

Generally, the larger the amount of the binder or the organic fiber added, the higher the bending strength. Therefore, it is effective to mix the organic fiber such as pulp into the outer layer in terms of strength. It is also effective in terms of cost. Further, it is also preferable to use a heat-sealing fiber which also serves as an organic fiber and a binder, in order to improve the strength and the like. However, in order to obtain an inorganic building board as a semi-combustible material, the total amount of organic components in the whole is 15% by weight including the binder.
It should be as follows. Further, in order to obtain an inorganic building board as a noncombustible material, the total amount of organic components needs to be 7% by weight or less. Therefore, the total amount of organic components in the outer layer portion may be determined so as to satisfy these.

The specific gravity of the outer layer portion is preferably 0.7 or more. If the specific gravity is less than 0.7, there is a problem that a dense outer layer portion cannot be obtained and the amount of water absorption increases.
This is because desired bending strength and good coatability cannot be obtained.

The inorganic foam forming the middle layer is for reducing the weight while maintaining the compressive strength. For example, there are perlite, shirasu foam, silica flour, glass foam, etc. Alternatively, two or more kinds can be used in combination. The inorganic foam has a particle size of 40.
It is possible to use those having a particle size of μ to 300 μ, and the maximum strength is obtained when the particles having a particle size of about 150 μ are used. Further, the composition ratio of the inorganic foam in the middle layer portion is preferably 45 to 70% by weight. If it is less than 45% by weight, the amount of the binder and other components added to form the intermediate layer portion relatively increases, so that the strength is improved, but the effect of lowering the specific gravity cannot be obtained. This is because if it exceeds 70% by weight, it becomes difficult to form a uniform layer.

The fibrous fine particles made of the inorganic fibers forming the middle layer portion are filled in the voids between the inorganic foams and are the same as the above-mentioned fibrous fine particles forming the outer layer portion. The fibrous fine particles of both need not necessarily be the same, and may be different if necessary. However, the composition ratio of the fibrous fine particles in the middle layer is 3
It is preferably from 0 to 50% by weight. If it is less than 30% by weight, it is insufficient to fill the voids formed between the inorganic foams, and the screw penetration force cannot be enhanced.
If the amount is more than wt%, the amount of the inorganic foam will be relatively reduced.
This is because the weight of the inorganic building board cannot be reduced.

Since the material and the amount of the binder forming the middle layer portion are the same as those in the case of the outer layer portion described above, the description thereof will be omitted. When it is used for either of them, it is more effective when used for the middle layer.

The specific gravity of the middle layer is preferably 0.4 or less. This is because if the specific gravity exceeds 0.4, not only it becomes difficult to reduce the weight of the inorganic building board, but also extremely high pressure is required during manufacturing, which impairs productivity.

As described above, the more the binder and the organic fibers are, the more the bending strength and the like are improved. Therefore, if necessary, organic fibers such as pulp may be used in the middle layer portion. However, in order to obtain an inorganic building board as a semi-incombustible material, the total amount of organic components needs to be 15% by weight or less as described above. Further, in order to obtain an inorganic building board as a noncombustible material, the total amount of organic components needs to be 7% by weight or less. Therefore, when using organic fibers such as pulp,
Care must be taken so that the total amount of organic components such as the binder is within the above range.

The overall specific gravity of the inorganic building board should be determined depending on the application, but if the overall specific gravity is made too small to reduce the weight, sufficient strength cannot be obtained. The specific gravity is preferably 0.5 or less. When the total specific gravity is set to 0.5 or less, the weight per sheet is about 7 kg in the so-called 9 mm-thick 3 × 6 plate, which is about 2/3 of the weight of the gypsum board.

Next, a method for manufacturing an inorganic building board according to this embodiment will be described. For example, mineral fibers, fibrous fine particles, and a binder are put into fresh water and stirred to obtain an aqueous slurry, which is wet-paper-processed to form outer layers (lower layer and upper layer).
To obtain a wet inorganic mat. On the other hand, the inorganic foam, the fibrous fine particles and the binder are uniformly mixed under a spray of fresh water to obtain a mixture for the middle layer, and the mixture is uniformly formed on the surface of the wet inorganic mat to be the lower layer obtained by wet papermaking. After spraying and depositing on the to form a middle layer portion, the wet inorganic mat to be the upper layer portion is laminated thereon to obtain a laminated body, which is pressed and integrated,
There is a manufacturing method for obtaining an inorganic building board by heating and drying.

In the above-mentioned manufacturing method, the pressing and drying steps may be replaced with the thermocompression-integrating, or the drying may be performed thereafter. Further, in the above-described manufacturing method, the manufacturing method in which the dry method and the wet method are combined has been described, but the manufacturing method is not necessarily limited to this, and all dry methods or all wet methods can be used, and an arbitrary manufacturing method can be selected.

[0019]

EXAMPLES Next, examples according to the present invention will be described. (Example) 38% by weight of rock wool as a mineral fiber,
55% by weight of wollastonite having a fiber length of 300μ, a fiber diameter of 5μ and an assect ratio of 60 as fibrous fine particles, and a mixture of 15% by weight of a total amount of a phenol resin and a balance of starch as a binder, 7% by weight of fresh water. Was added to and stirred to obtain an aqueous slurry having a concentration of 2%, which was introduced into a Fourdrinier paper machine for papermaking to obtain a wet inorganic mat to be a lower layer portion and an upper layer portion having a thickness of 4 mm.

On the other hand, 58% by weight of a mixture of pearlite and shirasu foam as an inorganic foam, 35% by weight of wollastonite as in the above-mentioned embodiment as fibrous fine particles, 4% by weight of starch as a binder, and phenol resin 1 % By weight and 2% by weight of the heat-sealing fiber as an organic fiber were mixed with 100 of these solid components under a spray of water of a ratio of 50 to obtain a mixture for the middle layer.

Then, the mixture for the middle layer is uniformly sprayed and deposited to a thickness of 26 mm on the wet inorganic mat to be the lower layer, and the wet inorganic mat to be the upper layer is arranged on the wet inorganic mat to form the entire thickness. A 32 mm thick laminate was obtained. Then, press the laminated body with a press having a pressure of 5 kg / cm ^{2 to} obtain a thickness of 9 mm.
After pressing until it became, it was dried in a drying oven at a temperature of 180 ° C., and further cut into an appropriate length to obtain an inorganic building board as a sample. The upper and lower layers of the sample had a thickness of 1.
The thickness of the intermediate layer was 5 mm and the thickness of the middle layer was 6 mm.

(Comparative Example) Rock wool 38% by weight as an inorganic fiber, calcium carbonate 55% by weight as an inorganic powder, and starch 7% by weight as a binder were added to fresh water and stirred to give a concentration. A 2% aqueous slurry was obtained, and this was introduced into a Fourdrinier paper machine to perform papermaking, to obtain a wet inorganic mat to be a lower layer portion and an upper layer portion having a thickness of 3 mm.

On the other hand, as the inorganic foam, 93% by weight of the same shirasu foam as in the above-mentioned embodiment and starch 4 as the binder were used.
% By weight, 1% by weight of a phenolic resin, and 2% by weight of the same heat-sealing fiber as the organic fiber in the embodiment are mixed with 100% of these solid components under a spray of water of a ratio of 50 to form an intermediate layer portion. A mixture was obtained.

Then, the mixture for the middle layer is uniformly sprayed and deposited on the wet inorganic mat as the lower layer so as to have a thickness of 26 mm, and the wet inorganic mat as the upper layer is arranged on the wet inorganic mat. A 32 mm thick laminate was obtained. Then, press the laminated body with a press having a pressure of 5 kg / cm ^{2 to} obtain a thickness of 9 mm.
After pressing until it became, it was dried in a drying oven at a temperature of 180 ° C., and further cut into an appropriate length to obtain an inorganic building board as a sample. The upper and lower layers of the sample had a thickness of 1.
The thickness of the intermediate layer was 5 mm and the thickness of the middle layer was 6 mm.

Next, the measurement results relating to the physical properties of the samples of Examples and Comparative Examples are shown below. Example Comparative example Thickness (mm) 9.05 9.05 Specific gravity 0.46 0.46 Bending strength (parallel) 90 70.5 (kgf / cm ² ) (orthogonal) 75 58.8 Screw penetration force (kgf) 27 18.3 Water absorption rate (%) 6.0 7.0 Moisture absorption linear expansion rate (%) 0.05 0.11 Fireproof Nonflammable Pass Nonflammable Pass

In the bending strength, (parallel) means a case of bending along the papermaking direction, and (orthogonal) means a case of bending along a direction orthogonal to the papermaking direction.
Further, the measurement result is obtained based on the following method. Bending strength: Based on JIS A5907-1977. Screw penetration force: Based on the test method according to JIS A5910. Water absorption rate: Indicates the degree of weight increase after immersion in water for 24 hours, based on JISA5403. Hygroscopic linear expansion coefficient: 2 in an atmosphere with a temperature of 45 ° C and humidity of 15%
The coefficient of linear expansion after being dried for 4 hours in an atmosphere having a temperature of 30 ° C. and a humidity of 90% after being dried for 4 hours is shown.

From the above measurement results, the specific gravity of the example is equivalent to that of the comparative example, but the bending strength of the example is about 30% larger than that of the comparative example. Therefore, it was found that the weight can be further reduced if the bending strengths are made equal.
It is considered that this is because the fibrous fine particles added to the upper and lower layers are intertwined with each other, and the fibrous fine particles added to the middle layer effectively bind and integrate the inorganic foam through the binder. Also, for the same reason, it was found that the linear expansion coefficient in the hygroscopic state in which the binder was loosened was smaller in the example than in the comparative example, and was excellent in dimensional stability. Moreover,
Since the screw penetration force of the example is about 50% larger than that of the comparative example, it is possible to further reduce the weight by forming the screw penetration force to be the same. This is because the fibrous fine particles added to the middle layer of the example made the middle layer of the example denser than that of the comparative example, and thus it is judged that the screw penetration force increased. Further, the fibrous fine particles made of inorganic fibers have a small apparent specific gravity and are bulky, but they are smaller than the inorganic powdery substance themselves, and moreover, in this embodiment, they are integrated by pressing, so that the inorganic building board The outer layer is more dense than the comparative example, and the coatability is improved.

From the above measurement results, it was found that the inorganic building board of the present invention according to the example has a smaller specific gravity than the inorganic building board of the comparative example, is lightweight, and is excellent in dimensional stability and paintability.

[0029]

As is apparent from the above description, according to the inorganic building board of the present invention, the middle layer portion formed by adding the binder with the inorganic foam and the fibrous fine particles as main components. The front and back surfaces of (1) and (2) are covered with the outer layer portion which is formed by adding a binder and containing mineral fiber and fibrous fine particles as main components. In other words, since the lightweight and dense middle layer is covered with the hard and dense outer layer, according to the present invention, the inorganic building board excellent in dimensional stability and paintability without impairing the lightness is provided. If it is formed so that the bending strength and the like are equal, there is an effect that the weight can be further reduced. Further, according to the method for producing an inorganic building board according to the present invention, not only the inorganic building board having the above-described effects can be obtained, but also by forming the outer layer portion of the upper layer portion and the lower layer portion by wet papermaking, fiber Since they are entangled with each other, the bending strength is improved, and since a dense surface is obtained, there is an effect that an inorganic building board excellent in paintability can be obtained.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masako Ryukaku No. 4-13 Honmachi, Chuo-ku, Osaka City, Osaka Prefecture Takenaka Corporation, Osaka Main Store No. 1 No. 1 Daiken Kogyo Co., Ltd. (72) Inventor Takao Akio Inami No. 1 Inami-cho, Tonami-gun, Toyama Prefecture No. 1 No. 1 Daiken Kogyo Co., Ltd.

Claims (2)

[Claims] 1. An inorganic foam and an inorganic material are provided between a lower layer portion and an upper layer portion, which are outer layers formed by adding minerals and fibrous fine particles composed of inorganic fibers as a main component and adding a binder. The main component is fibrous fine particles made of fibers, and
An inorganic building board, characterized in that a middle layer portion, to which a binder is added, is formed and integrated in layers. 2. A step of forming a wet inorganic mat as a lower layer from a slurry containing a mineral fiber and fibrous fine particles of an inorganic fiber as a main component and a binder added thereto, an inorganic foam and an inorganic fiber. A step of spraying and depositing a mixture for the middle layer, which is mainly composed of fibrous fine particles consisting of, and to which a binder is added, on the wet inorganic mat in a uniform thickness, and a fibrous state consisting of mineral fibers and inorganic fibers A step of laminating a wet inorganic mat as an upper layer obtained by papermaking from a slurry containing fine particles as a main component and a binder added thereto on the mixture for the intermediate layer to obtain a laminated body, and the laminated body The method for manufacturing an inorganic building board, comprising the steps of: