JPS5844056B2 - Method for manufacturing noncombustible construction boards - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for manufacturing noncombustible building boards.

Conventionally, noncombustible construction boards have been produced by forming hydraulic inorganic raw materials such as cement with asbestos into a board shape with the addition of water.
It is often manufactured by curing this uncured plate-like material.

In other words, by mixing natural mineral fibers such as asbestos into hydraulic inorganic raw materials such as cement, the strength of construction boards can be maintained even stronger without affecting the non-combustibility of the construction boards. It is being said.

However, in recent years, due to the depletion of asbestos resources, the cost of asbestos has increased and it has become extremely difficult to obtain, making it difficult to use asbestos.
Alternatively, the omission of asbestos is being considered.

Glass fibers, synthetic fibers, etc. have been proposed as fibers to replace asbestos, but glass fibers have problems with alkali resistance, and furthermore, they can be mixed into hydraulic inorganic raw materials such as cement, and water can be added to them. When an uncured plate-like body is shaped into a bottom shape, glass fibers have low wettability to uncured raw materials, so when bending force is applied, they easily slip out of the uncured raw materials, and are not suitable for reinforcement in the uncured state. Not very effective, and
It has disadvantages in that it has poor water-absorbing properties, is not very effective in improving water permeability, and is therefore troublesome to control moisture and maintain shape during the manufacturing process.

In addition, in the case of synthetic fibers, in the curing process of architectural boards,
If autoclave curing is performed, the synthetic fibers will melt at the high temperatures during curing and lose their form as reinforcing fibers, so room temperature curing such as underwater curing or natural curing must be used, making it impossible to increase production efficiency. It has such drawbacks.

On the other hand, natural organic fibers such as pulp have been proposed in place of asbestos, but since these are flammable, they have the disadvantage that if the amount added is large, the building material will not become non-flammable.

In view of the above, the purpose of this invention is to provide a method that enables the production of noncombustible construction boards that can minimize the use of asbestos, using the dry process and autoclave curing, which have the highest production efficiency. It is something that

That is, the method for producing a noncombustible building board according to the present invention includes combustible natural organic fibers of 0.1 to 5.0% by weight, natural mineral fibers of 4 to 10% by weight, and a C3078102 molar ratio of 0.4.
A raw material containing 10 to 40% by weight of a mixture of cement and silica and 20 to 70% by weight of fine aggregate within the range of ~1.0 is spread on a running belt conveyor, and the spread layer is penetrated by water. This method is characterized by compressing the molded product using rolls, taking it out from a belt conveyor, and autoclaving it.

In the present invention, combustible natural organic fibers include sheets made from pulp slurry made into fibrous cellular material by dissolving and removing lignin and resin from softwood and hardwood using a soda method, sulfite method, sulfate method, chlorine method, etc. The fibers are dried to a moisture content of 10% or less, and the center fiber length is 1.0 to 5.5 m, and the center fiber is 0.02 to 0.04 m by impact with a high-speed rotating hammer.
Asbestos is used as the natural mineral fiber.

The amount of this combustible natural organic fiber (pulp) added is 0.1~
The reason why the amount of asbestos added is 4 to 10% by weight is that if the amount of pulp added is 5% by weight or more, the nonflammability of the building material will be significantly impaired, and if it is 0.1% by weight or less,
In order to maintain the formability of the sprayed raw material layer, it is necessary to increase the amount of asbestos added, and the amount of asbestos added must be increased from 4 to 10%.
The weight percentage is the above combustible natural organic fiber (pulp)
It is determined by the amount of pulp added and the relative relationship, but if it is more than 10% by weight, the cost will increase, and if it is less than 4% by weight, the amount of pulp added must be increased beyond the limit. It is.

The above combustible natural organic fibers (pulp) and natural mineral fibers (
Both asbestos (asbestos) contributes to the uncured formability of the raw material layer spread on the belt and to reinforcing fibers after curing.If the amount of asbestos added is reduced within the above range, the pulp will change accordingly. is increased, and the two work together to strengthen the molded body.

Therefore, the weight% of the mixed state of both is approximately 9 to 9.
A blending amount of about 11% by weight is sufficient.

Ordinary Portland cement is used for cement, and as silica, it has a purity of 90% or more and a Blaine value of 200.
0 to 4000 ffl/g is used.

Also, the reason why the molar ratio of CaO and SiO2 was limited to the range of 0.4 to 1.0 is that if it is less than 0.54, sufficient strength cannot be imparted to the plate material after hardening, and if it is more than 1.0, it will not be possible to impart sufficient strength to the cured material. This is because a large amount of lime remains as free lime, causing efflorescence.

In addition, as fine aggregate, hard sandstone, hard limestone, basalt,
It is preferable to use one or a mixture of two or more types of andesite as raw stone, and the particle size is 4 meshes all through, and the amount of non-passage through 200 meshes is 5% or less.

This means that when a large amount of 200 mesh fine aggregate is used,
The moisture permeability of the sprayed raw material layer decreases, making it impossible for the molded product to absorb the moisture necessary for the curing reaction, and if the size is 4 mesh or more, the unevenness of the surface of the molded product becomes noticeable and the surface of the building material becomes rough. This is because deterioration in appearance is unavoidable.

The reason why the amount of aggregate added was set at 20 to 70% by weight is as follows.
If it is less than 20% by weight, the permeability of water into the sprayed raw material layer will be poor and sufficient water utilization reaction will not occur, and if it is more than 70% by weight, the strength of the building material will decrease and the specific gravity will increase. This is because the larger the building, the heavier the building materials.

In this invention, the autoclave curing is conditioned on the ability to generate calcium silicate by causing a hydrothermal reaction between cement and silica.

Specifically, using saturated steam of 4 to 15 atmospheres,
Curing is performed for 15 hours.

The drawings show manufacturing equipment used in the invention.

In the figure, 1 is a belt conveyor.

2a is a 17th rough box, in which the raw material A1 continuously fed from the raw material conveyor 3a is agitated by a blade roll 4a and deposited on the belt conveyor 1.

This deposited raw material is leveled by a spike roll 5a,
Next, the air in the leveling layer is removed by compression with the perforated roll 6a.

The amount of raw materials supplied by the first fluff box 2a is 50 to 70% of the total raw materials for the final version.

7 is a water supply device such as a shower or a flow coater, and the raw material layer that has passed through the perforated roll 6a is moistened with water from this water supply device 7 to a water content of 5 to 15%.

2b is the 27th rough box, in which the raw material A2 continuously fed from the raw material conveyor 3b is passed onto the wet raw material layer by a bladed roll 4b, a leveling roll 5b, and a perforated roll 6b in the same manner as described above. It is formed in a layered manner.

The amount of raw material supplied from the 27th rough box 2b is 50 to 30% of the final sheet metal raw material.

8 is a walk box, which has a curtain-like cloth 81 through which water drips.

The raw material layer that has passed through the perforated roll 6b at the outlet of the second fluff box comes into contact with the cloth 81 of the water box 8.
1 is moistened with flowing water, resulting in a water content of 5 to 15%.

Next, it is compressed by a bank roll 9 and further cut to a fixed length by a roll cutter 10.

Reference numeral 11 denotes a veneer scattering container, in which an uncured molded plate cut to a specified length is further compressed by a middle roll 12, and veneer (coloring material mainly made of foreign material) from the veneer scattering container 11 is sprayed on the surface thereof. .

13 is a granule scattering container, in which the veneer scattering forming plate is compressed again by the front roll 14, and the granule (colored silica sand) from the granule scattering container 13 is applied to the surface thereof.
are scattered sparsely.

The dispersed particles are embedded in the veneer layer by the grain roll 15.

Then, the uncured molded plate is taken out from the belt conveyor and, if necessary, is naturally cured for 1 to 3 days.

This natural curing is to give the board the strength necessary when punching it into a product shape (for example, a tile shape).
For example, it is omitted for wall board materials.

Finally, the uncured molded product is transported into an autoclave and cured with high-temperature and pressurized steam.

In the above, moisture permeates into the raw material layer smoothly because the aggregate in the raw material has a relatively large particle size and little variation in particle size, and the hardening reaction takes place smoothly. It can provide sufficient moisture.

When there is insufficient moisture, the cured product cannot be given sufficient strength, and when there is excess moisture, the uncured product becomes too soft.
Breakage of the uncured body is unavoidable when the uncured body is taken out from the belt conveyor.

In the present invention, such disadvantages can be overcome by the cooperation of combustible natural organic fibers and natural mineral fibers.

Furthermore, since the uncured product has excellent crack resistance and bending breakage resistance due to the above-mentioned fibers, hair cracks, bending breaks, etc. may occur in the uncured product when it is taken out from the belt conveyor. do not have.

Furthermore, the combustible natural organic fibers contained in hardened building materials provide reinforcement through cooperation with asbestos, and the amount of combustible natural organic fibers required to provide the strength required for hardened building materials is limited. Therefore, hardened building materials are subject to Ministry of Construction Notification No. 1.
It is fully recognized as a noncombustible building material designated by No. 828,
Furthermore, since the use of asbestos can be reduced by increasing the amount of combustible natural organic fiber within a limited range, it becomes possible to manufacture non-combustible building materials at low cost.

When the strength and other tests of the plate material manufactured by the manufacturing method according to the present invention were conducted, the following data were obtained, and it was confirmed that it has superior effects compared to conventional noncombustible building materials.

Board thickness 5-15mm Bending strength 100-200kg/ffl The apparent specific gravity is 1.70~1°95 Water absorption rate 14-20% Expansion rate: 0.3% or less Passed flame retardancy test

[Brief explanation of drawings]

The drawing is a conceptual diagram of the manufacturing apparatus used in this invention. A1 + A2... Raw material, 1... Belt conveyor, 2a, 2b... Fluff box, 3a, 3b... Raw material supply conveyor, 4a,
4b...Roll with feathers, 5a, sb...
... Leveling roll, 6a, 6b ... Perforated roll, 7 ... Water sprinkler, 8 ... Water box, 9 ... Pressure roll , 10...
...Roll cutter, 12,14.15... Pressure roll.

Claims (1)

[Claims] 1 A combination of cement and silica with 0.1 to 5.0% by weight of combustible natural organic fibers, 4 to 10% by weight of natural mineral fibers, and a Cab/5in2 molar ratio of 0.4 to 1.0. A raw material containing 10 to 40% by weight of the mixture and 20 to 70% by weight of fine aggregate is spread on a running belt conveyor, the spread layer is compressed and formed by rolls under the penetration of water, and this molded body is transferred to the belt conveyor. A method for producing noncombustible construction boards, which comprises taking them out and curing them by autoclaving.