JPH09144158A - Inorganic building board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inorganic building board which is small in weight, high in the strength, and excellent in the fire resistance by forming the mineral fiber to constitute an upper layer part and a lower layer part of the inorganic building board of rock fiber which is mainly composed of SiO2 and MgO. SOLUTION: An inorganic building board is formed by integrating an intermediate layer part 3 which is composed mainly of the inorganic formed body and the binder between an upper layer part 1 and a lower layer part 2 which consists mainly of the mineral fiber, the inorganic powder, and the binder. The mineral fiber is formed of rock fiber composed mainly of SiO2 and MgO. The rock fiber preferably has the composition consisting of, by weight, 50-55% SiO2 , 30-40% MgO, and the balance inevitable impurities. Because the rock fiber is high in the strength, and excellent in the heat resistance, the weight is reduced and/or the strength is increased according to the applications to obtain the inorganic building board which is small in strength deterioration and thermal shrinkage especially when water is absorbed.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an inorganic building board, in particular,
The present invention relates to a lightweight inorganic building board which has little strength reduction and heat shrinkage when absorbing water.

[0002]

2. Description of the Related Art Conventionally, mineral fibers, inorganic powders, organic binders, and organic fibers added as necessary are used to form outer layers, namely upper and lower layers. Part of the inorganic building board obtained by forming an intermediate layer part consisting of an inorganic foam, a binder, and a fibrous material optionally added between the upper and lower layer parts and pressing and integrating the parts. There is.

Such inorganic building board uses gypsum board, calcium silicate board, wood cement by using rockwool composed of the following components obtained by fiberizing blast furnace slag by a high speed centrifugal method as mineral fiber. Compared to boards and plywood, it is generally lighter in weight, stronger, and superior in fire protection.

SiO ₂ MgO CaO Al ₂ O ₃ Fe ₂ O ₃ 38-44 4-8 35-39 12-15 0.2-0.6 (wt%)

However, depending on the application, it is necessary to further reduce the weight, increase the strength, and improve the fireproof property, and the above-mentioned inorganic building board has a problem that the desired conditions are not satisfied.

In view of the above problems, it is an object of the present invention to provide an inorganic building board which is lighter in weight, has higher strength, and is excellent in fire protection.

[0007]

[Means for Solving the Problems] Claim 1 according to the present invention
In order to achieve the above-mentioned object, the inorganic building board described above includes an inorganic foam and a binder between an upper layer portion and a lower layer portion which are outer layer portions mainly composed of mineral fibers, an inorganic powder and a binder. In an inorganic building board in which a middle-layer portion, which is a main component, is formed and integrated, rock wool having SiO ₂ and MgO as main components is used as a mineral fiber. Further, the invention of claim 2 is the rock wool of claim 1,
SiO ₂ 50 to 55% by weight, MgO 30 to 40% by weight,
And, it is characterized in that it consists of unavoidable impurities.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment according to the present invention will be described with reference to the accompanying drawings of FIG. Examples of rock wool of mineral fibers forming the upper layer portion 1 and the lower layer portion 2 which are outer layer portions include so-called nickel wool having the following component composition. Nickel wool is made from nickel slag as a main raw material by a high speed centrifugal method, and its fiber diameter and bulk specific gravity are almost the same as those of conventional slag wool whose main raw material is blast furnace slag. However, the strength of nickel wool is 1.3 times or more that of conventional slag wool, and its heat resistance temperature is higher than conventional slag wool by about 100 ° C or more. It has excellent alkali resistance and is immersed in water. The pH is 7.0 or less in the case of doing, and it has low alkalinity which is not found in conventional slag wool.

As the nickel wool, one having the following component composition is used. _{SiO 2 MgO CaO Al 2 O 3} Fe 2 O 3 50~55 30~40 0.4~0.8 1.0~2.0 4.0~5.0 ( wt%)

Nickel wool having the above-mentioned composition is used because the applied temperature at constant pressure specific heat is C, as compared with the above-mentioned slag wool whose main raw material is blast furnace slag.
This is because it contains a large amount of MgO, which is about twice as large as aO.

The composition ratio of nickel wool in the outer layer portion is preferably 35 to 70% by weight. This is because if it is less than 35% by weight, the proportion of fibers is small and it is difficult to obtain the required strength, and if it exceeds 70% by weight, the proportion of the inorganic powder is small and hardness and the like are insufficient.

The inorganic powder forming the outer layer is used to increase the hardness and the screwing performance while maintaining the fire resistance, and is, for example, calcium carbonate, silica sand, micro silica, slag, aluminum hydroxide. And the like. The composition ratio of the inorganic powder in the outer layer is 2
It is preferably from 0 to 50% by weight. If it is less than 20% by weight, the hardness and screwing performance will be insufficient.
This is because if it exceeds 0% by weight, the proportion of fibers is small and it is difficult to obtain the desired strength. The strength of the outer layer is about 1 particle size.
The case where the 50 μm inorganic powder is used is the largest, but the inorganic powder may have an average particle size of 40 μm to 300 μm.

The binder forming the outer layer portion is for connecting and integrating the rock wool and the inorganic powder, and examples thereof include synthetic resins such as polyvinyl alcohol resin and phenol resin, and starch. These can be used alone or in combination of two or more. The composition ratio of the binder in the outer layer portion is preferably 5 to 20% by weight. These are appropriately determined in terms of use and fire resistance.

If necessary, a fibrous material other than rock wool, such as pulp, may be added to the outer layer portion. Generally, as the added amount of the binder and the organic fiber is increased, the bending strength is improved. Therefore, it is effective to mix the organic fiber such as pulp into the outer layer portion in terms of strength, and also in terms of cost. It is valid. 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 all organic components including the binder is 15% by weight or less. Also, in order to obtain an inorganic building board as a non-combustible material, it is necessary that the total amount of organic components is 7% by weight or less.

The inorganic foam forming the middle layer 3 is for reducing the weight while maintaining the compressive strength.
There are pearlite, shirasu foam, silica flour, glass foam, etc. These can be used alone or in combination of two or more kinds. The composition ratio of the inorganic foam in the middle layer 3 is preferably 50-80% by weight. If it is less than 50% by weight, the proportion of the binder added for forming the middle layer portion and the other proportions relatively increase and the strength is improved, but the effect of lowering the specific gravity cannot be obtained. This is because when the content exceeds the weight%, the proportion of the binder is small and the strength is insufficient.

If necessary, a fibrous material for connecting the inorganic foams may be added to the intermediate layer portion 3, or an inorganic powdery material may be added to fill the space between the inorganic foams. You may add.

Examples of fibrous materials include mineral fibers such as rock wool and slag wool, synthetic resin fibers such as polypropylene fibers, and pulp.
These can be used alone or in combination of two or more. The composition ratio of the fibrous material in the middle layer is 1
Preferably, the content is 10 to 10% by weight. These are for connecting the inorganic foams and are determined by the properties of the fibers to be added.

Examples of the inorganic powder include calcium carbonate, aluminum hydroxide and the like, and these can be used alone or in combination of two or more kinds. These are added when the density of the middle layer portion is increased due to screwing property and the like, and it is necessary to set the content to about 20% or less at the maximum.

As described above, the more the added amount of the binder and the organic fiber is, the more the bending strength is improved. Therefore, organic fiber such as pulp may be used as the fibrous material in the middle layer 3. However, in order to obtain an inorganic building board as a quasi-incombustible material, the total amount of organic components is set to 15% by weight or less of the total, and in order to obtain an inorganic building board as a non-combustible material, A guideline is 7% by weight or less of the total amount of the components. 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.

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. 1,
2 or the middle layer part 3, when used for the middle layer part 3
Is more effective when used for.

Next, a method for manufacturing an inorganic building board according to this embodiment will be described. First, rock wool, an inorganic powder, a fibrous material and a binder are suspended in water to obtain an aqueous slurry, which is wet paper-formed to form a lower layer portion 2 and an upper layer portion 1 (outer layer portion), a wet inorganic mat. To get On the other hand, an inorganic foam, an inorganic powder, a fibrous substance and a binder are mixed to obtain a mixture, and the mixture is uniformly wet-spread and deposited on the surface of the wet inorganic mat to be the lower layer 2 obtained by wet papermaking. Then, there is a method of manufacturing an inorganic building board by forming the middle layer portion 3 and stacking the wet inorganic mat to be the upper layer portion 1 thereon, press-integrating the wet inorganic mat, and then drying.

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 dry methods or all wet methods may be used. Any manufacturing method may be selected. it can.

[0023]

【Example】

(Example) 65% by weight of rock wool having the following composition as mineral fibers, 20% by weight of aluminum hydroxide as an inorganic powder, 5% by weight of pulp, and 10% by weight of powdered phenol and starch as a binder in clear water. Throw in,
About 2% of the slurry obtained by stirring was made into paper by a Fourdrinier paper making machine to obtain a wet mat having a thickness of 8 mm, which was to be the upper layer 1 and the lower layer 2.

SiO ₂ Al ₂ O ₃ CaO Fe ₂ O ₃ MgO 53 1.5 0.6 4.5 35 (parts by weight) The presence of trace amounts of oxides of chromium, nickel, etc. was recognized as unavoidable impurities. It was

On the other hand, 65% by weight of pearlite as an inorganic foam, 20% by weight of aluminum hydroxide as an inorganic powder, 5% by weight of pulp, powdered phenol and starch 1
0 wt% was mixed under a spray of fresh water to obtain a mixture. Then, the mixture is sprayed and deposited on the upper surface of the wet mat to be the lower layer section 2 to form the middle layer section 3, and the wet mat to be the upper layer section 1 is laminated on the upper surface to obtain a laminate having a thickness of 56 mm. It was Then, this laminated body is heated at a temperature of 180 ° C. and a pressure of 5 Kg.
/ Cm ² hot press for 20 minutes
Simultaneously with the pressing, the binder was activated and integrated to obtain a plate-shaped sample having a specific gravity of 0.7 and a thickness of 18 mm. Note that the sample of this example satisfies the standard of quasi-incombustible material because the organic component is about 15% of the whole.

Comparative Example Under the same conditions as in the above-mentioned Examples except that a commercially available rock wool having the following composition was used as the mineral fibers, specific gravity was 0.7 and thickness was 18 mm.
I got a sample of.

SiO ₂ Al ₂ O ₃ CaO Fe ₂ O ₃ MgO 44 12 35 0.5 6 (parts by weight) In addition, trace amounts of oxides of titanium, zinc, manganese, etc. were recognized as unavoidable impurities.

With respect to the samples according to the examples and comparative examples, the strength in the normal state, the strength in absorbing water and the heat shrinkage were measured. The measurement results are shown below. Example Comparative Example Strength in normal state (Kgf / cm ² ) 240 200 Strength in water absorption (Kgf / cm ² ) 150 124 Heat shrinkage rate (%) 0.8 9.0

The measurement results are obtained based on the following method. The strength under normal conditions is JIS-A-59.
It was measured based on 07. The strength when absorbing water is
After immersing the sample in water for 24 hours, JIS-A-5
It is measured according to 907. The heat shrinkage is JI
Based on S-A-1304, it was obtained by heating at a temperature of 800 ° C. for 30 minutes.

As is clear from the above-mentioned measurement results, the strength of the working example in the normal state was 10% higher than that of the comparative example, so that it was found that the working example had a strength equal to or higher than that of the comparative example. Further, in the strength at the time of absorbing water, the example has a strength higher than that of the comparative example by 20% or more. Therefore, it is clear that the strength reduction due to the water absorption is smaller in the example than in the comparative example. In addition, since the heat shrinkage rate of the example is about 1/10 or less of that of the comparative example, it was found that a gap is less likely to occur and the example is superior in heat resistance. This is because the example is more SiO ₂ , MgO than the comparative example.
While containing a large amount of Al ₂ O ₃ ,
It is considered that this is because the content of CaO is smaller than that in the comparative example.

Further, from the above measurement results, not only is the strength in the normal state of the embodiment not less than twice that of the wood cement board (WCB) used as a fire-resistant base plate, but also the strength when absorbing water. It was found that the decrease was small. In addition to this, since the specific gravity of the wood cement board is about 1.2, when both are molded into a plate-shaped body having the same thickness, the embodiment has a specific gravity of about 40.
It has been found that it can be manufactured lightly by more than 10%, which can reduce transportation costs and facilitate work.

[0032]

As is clear from the above description, according to the inorganic building board of the present invention, the upper and lower layers, which are the outer layers, are made of rock wool containing SiO ₂ and MgO as the main components. There is. Further, rock wool containing SiO ₂ and MgO as main components has higher strength than conventional slag wool and has excellent heat resistance, so that it is possible to reduce the weight and increase the strength depending on the application. Both have the effect that an inorganic building board with a small heat shrinkage rate can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view of an inorganic building board according to the present invention.

[Explanation of symbols]

 1 ... upper layer part, 2 ... lower layer part, 3 ... middle layer part.

Claims (2)

[Claims] 1. An intermediate layer part mainly composed of an inorganic foam and a binder is integrally formed between an upper layer part and a lower layer part which are outer layer parts mainly composed of mineral fibers, an inorganic powder and a binder. The inorganic building board as described above, wherein the mineral fiber is rock wool containing SiO ₂ and MgO as main components. 2. The rock wool is SiO ₂ 50-5.
The inorganic building board according to claim 1, wherein the inorganic building board is composed of 5% by weight, 30 to 40% by weight of MgO, and unavoidable impurities.