JP2680772B2 - 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 an inorganic building board used as a base material for a wall or the like.

[0002]

2. Description of the Related Art Conventionally, gypsum board has been generally used as a base material.
Since gypsum board has low water resistance and moisture resistance, it could not be used in a humid basement or a kitchen with a steam source. For this reason, calcium silicate boards having excellent water resistance and moisture resistance are used in basements and the like.

However, since the calcium silicate plate has a large specific gravity (0.9 or more), it has a large weight per sheet and is inconvenient for transportation and construction. Calcium silicate plate is used as a part of exterior material such as eaves ceiling by utilizing water resistance and moisture resistance, but since freeze-thaw property is about 50 cycles (equivalent to use for 2 to 3 years), There is a problem that it cannot be used in cold regions.

In view of the above problems, it is an object of the present invention to provide an inorganic building board which is excellent in water resistance and moisture resistance, is lighter in weight than calcium silicate board, and is excellent in freeze-thaw property. And

[0005]

In order to achieve the above-mentioned object, an inorganic building board according to the present invention comprises a mineral fiber and an inorganic powder as main components, and a specific gravity formed by adding a binder. Between the lower layer part and the upper layer part, which are outer layer parts of 0.8 or more, a middle layer part, which is mainly composed of an inorganic foam and has a specific gravity of 0.4 or less, to which a binder is added, is formed into a layer and integrated as a whole. The specific gravity is 0.55 or more.

The mineral fibers forming the outer 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 outer layer is 20 to 60% by weight.
It is preferred that If the content is 20% by weight or less, the bending strength is low, and the surface is easily broken at the time of screw driving,
This is because if it is 60% by weight or more, the amount of the inorganic powder to be added is relatively low, and the surface hardness and overall strength cannot be increased.

The inorganic powdery material forming the outer layer portion is for increasing hardness and screwing performance while maintaining fireproofness. For example, calcium carbonate, silica sand, micro silica, slag, aluminum hydroxide. Etc. can be mentioned. The composition ratio of the inorganic powder in the outer layer is 4
It is preferably from 0 to 70% by weight. This is because if the amount is 40% by weight or less, the desired surface hardness cannot be obtained.
This is because if the content is more than 10% by weight, the ratio of the mineral fibers is relatively reduced, and the desired strength cannot be obtained. In addition,
The strength of the outer layer portion is highest when the inorganic powder having a particle size of about 150 μ is used, but the inorganic powder has an average particle size of 40 μ to 3 μm.
It may be 00μ.

The binder forming the outer layer portion is for connecting and integrating the mineral fiber and the inorganic powder.
Examples thereof include polyvinyl alcohol resins, synthetic resins such as phenolic resins, starches, etc.
Alternatively, two or more kinds can be used in combination.

Generally, the more the binder and the organic fibers are, the more the bending strength is improved. Therefore, it is effective to mix the organic fibers such as pulp into the outer layer in terms of strength and also in terms of cost. Is also effective. Further, it is also preferable to use a fusible fiber that doubles as a fibrous material and a binder in order to improve strength and the like. However, in order to obtain an inorganic building board as a quasi-incombustible material, it is necessary that the total amount of organic components in the outer layer portion is 15% by weight or less including the binder. 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.

The reason why the specific gravity of the outer layer portion is 0.8 or more is as follows. That is, when the proportion of the inorganic powder is constant, for example, 60% by weight and the composition of the other material is made different to form the outer layer portion, between the specific gravity and the surface hardness of the outer layer portion, and the specific gravity and bending. There is a correlation with the strength, and the surface hardness and bending strength increase as the specific gravity increases. Then, in practical use, in order to obtain the outer layer portion having substantially the same surface hardness and bending strength as the calcium silicate plate, the specific gravity of the outer layer portion needs to be 0.8 or more. Further, if the specific gravity is 0.8 or less, a dense outer layer portion cannot be obtained, the amount of water absorption increases, and desired water resistance or the like 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 composition ratio of the inorganic foam in the middle layer is preferably 65 to 95% by weight. 6
When the content is 5% by weight or less, the proportion of the binder and other components added to form the middle layer portion relatively increases, so the strength is improved, but the effect of lowering the specific gravity cannot be obtained. This is because if it is 95% by weight or more, it becomes difficult to form a uniform layer.

If necessary, a fibrous material may be added to the intermediate layer portion to connect the inorganic foams to each other. Examples of the fibrous material include mineral fibers such as rock wool and slag wool. In addition to synthetic resin fibers such as polypropylene fibers, pulp and the like can be mentioned, and these can be used alone or in combination of two or more kinds. The composition ratio of the fibrous material in the middle layer is preferably 1 to 30% by weight. This is because if it is 1% by weight or less, the inorganic foam cannot be sufficiently connected, and if it is added in an amount of 30% by weight or more, the amount of the inorganic foam is relatively decreased and the weight of the inorganic building board cannot be reduced. is there.

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, description thereof will be omitted. However, the fusible fiber may be added to either the outer layer portion or the middle layer portion. When used for, the effect is greater when used for the middle layer.

The reason why the specific gravity of the middle layer portion is 0.4 or less is that if the specific gravity is 0.4 or more, it becomes difficult to reduce the weight of the inorganic building board, and at the same time, it is extremely This is because high pressure is required to hinder productivity.

As described above, the more the binder and the organic fibers are, the more the bending strength is improved. Therefore, organic fibers such as pulp may be used as the fibrous material in the middle layer portion. However, in order to obtain an inorganic building board as a quasi-incombustible material, the total amount of organic components needs to be 15% by weight or less even in the middle layer portion. Further, in order to obtain an inorganic building board as a non-combustible material, the total amount of organic components needs to be 7% by weight or less, as in the case of the outer layer portion described above. Therefore, when organic fibers such as pulp are used instead of mineral fibers, it is necessary to take care that the total amount of organic components such as a binder is within the above-mentioned range.

The overall specific gravity should be determined depending on the required use of the inorganic building board, but if the overall specific gravity is made small and weight reduction is required, sufficient strength cannot be obtained. Therefore, balance between strength and weight reduction is required. To 0.55 is set as the minimum specific gravity.

Next, a method for manufacturing an inorganic building board according to this embodiment will be described. For example, a mineral fiber, an inorganic powder, and a binder are suspended in water to obtain an aqueous slurry, which is wet-processed to obtain a wet inorganic mat which will be a lower layer portion and an upper layer portion (outer layer portion). On the other hand, inorganic foams, fibrous materials,
An inorganic powder and a binder are mixed to obtain a mixture, and the mixture is evenly sprayed and deposited on the surface of the wet inorganic mat to be the lower layer part obtained by wet papermaking to form the middle layer part, and After laminating and pressing the wet inorganic mat to be the upper layer,
There is a method of manufacturing an inorganic building board by drying and integrating.

In the above-mentioned manufacturing method, the manufacturing method in which the dry method and the wet method are combined has been described. However, all the dry methods or all the wet methods may be used, and an arbitrary manufacturing method is selected. it can.

[0019]

EXAMPLES Next, examples according to the present invention will be described. (Example 1)

40 parts by weight of rockwool, 50 parts by weight of calcium carbonate, 5 parts by weight of aluminum hydroxide, 5 parts by weight of a mixture of powdered phenol and starch, and some other amount of sizing agent, coagulant, etc. are added to fresh water and stirred. 2%
The obtained aqueous slurry was introduced into a Fourdrinier papermaking machine for papermaking to obtain a wet inorganic mat to be the lower layer and the upper layer having a thickness of 3.5 mm.

On the other hand, 48 parts by weight of pearlite as an inorganic foam, 40 parts by weight of shirasu foam, 5 parts by weight of aluminum hydroxide added to improve fire resistance, and 7% by weight of a mixture of powdered phenol and starch, These 100 solid components were mixed under a spray ratio of water 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 9 mm on the wet inorganic mat serving as the lower layer, and the wet inorganic mat serving as the upper layer is arranged on the wet inorganic mat. A 16 mm thick laminate was obtained. Then, this laminated body is pressed with a press having a pressure of 15 kg / cm ² to a thickness of 6
After pressing to a thickness of mm, it was dried in a drying oven at a temperature of 180 ° C. for 90 minutes, and further cut into an appropriate length to obtain an inorganic building board, which was used as a sample. The upper and lower layers of the sample each had a thickness of 1.5 mm and a specific gravity of 1.0, and the middle layer had a thickness of 3 mm and a specific gravity of 0.2.

Comparative Example A commercially available calcium silicate plate was used as a sample.

Next, the measurement results regarding the physical properties of the examples and comparative examples are shown below. Examples Comparative Examples Specific gravity 0.6 0.9 Thickness (mm) 6 6 Weight per sheet (kg / sheet) 6 9 Bending strength (kg / cm ² ) 95 76 Screw penetration force (kgf) 21 56 Surface hardness ( kgf) 93 94 Water absorption rate (%) 25 64 Dimensional change rate (%) 0.07 0.08 Freeze solubility (cycle) 300 50

The above measurement results are obtained based on the following method. Bending strength: Based on JIS 5907-1977. Screw penetration force: Based on a test method according to JIS A5910. Surface hardness: JIS HARDNESS TESTER
based on. Water absorption rate: Indicates the degree of weight increase after immersion in water for 24 hours, based on JISA5403. Dimensional change rate: Indicates the degree of dimensional change after immersion in water for 24 hours, and is based on JISA5418. Freeze-thaw property: Based on JIS A1435.

From the above measurement results, the weight per sheet of the example was two-thirds that of the comparative example. For this reason, when transporting the calcium silicate board, due to the weight limitation, the truck could use only less than half of the allowable loading capacity, but in the case of the inorganic building board of the present application, the volume is larger than that of the calcium silicate board. Can be loaded onto trucks by 50% more. As a result, the physical distribution cost can be significantly reduced, and the carrying-in and mounting work to the construction site becomes easy. Also, the bending strength of the example is 25% or more larger than that of the comparative example, and it is less likely to be deformed. Although the example has a screw penetration force smaller than that of the comparative example, it is said that the screw penetration force is 2.5 or more times as much as the weight of the building board, and there is no practical problem. Yes,
There is no particular problem. Furthermore, in freeze-thaw properties the comparative example was 50 cycles, which only meant that it could withstand 2-3 years of use, whereas the example is 30 cycles.
0 cycles, which means it can withstand 10 to 20 years of use. Therefore, there is no problem even if it is used outdoors, that is, it has low water absorption and is not directly exposed to rainwater, that is, it is used for an eaves ceiling or the like.

From the above measurement results, it was found that the inorganic building board of the present invention, which is an example, has a smaller specific gravity, is lighter in weight, and is superior in freeze-thaw property than the calcium silicate board that is a comparative example.

[0028]

As is apparent from the above description, according to the present invention, the middle layer portion having a specific gravity of 0.4 or less, which is formed by adding an inorganic foam as a main component and a binder, is a mineral substance. It will be covered with the outer layer part which has a specific gravity of 0.8 or more, which is formed by adding a binder and which has fibers and an inorganic powder as main components. In other words, since the light middle layer is covered with the hard and dense outer layer, according to the present invention, the surface is hard, screw-fastening is possible, and the bending strength is high, and it is more freeze-thaw than the calcium silicate plate. There is an effect that an excellent lightweight inorganic building board can be obtained.

Claims (1)

(57) [Claims] 1. An inorganic material is provided between a lower layer portion and an upper layer portion, which are outer layer portions mainly composed of mineral fibers and inorganic powders and having a specific gravity of 0.8 or more formed by adding a binder. An inorganic building board comprising a foam as a main component, and an intermediate layer portion having a specific gravity of 0.4 or less, to which a binder is added, formed and integrated into a layer so that the overall specific gravity is 0.55 or more.