JP2002274925A - Inorganic cement board and method of manufacturing for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inorganic cement board which has not only the small amount of whiskers and defects, but has good form ability to enable the deep rugged patterns and about 0.1% of a dimensional change rate and is excellent in strength and a method of manufacturing this cement board. SOLUTION: This inorganic cement board is formed by incorporating pulp previously subjected to opening in the presence of a suitable volume of water into the cement board.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention aims to develop a method for manufacturing a thick siding board having excellent shapeability.
Thick siding board manufactured by the method of the present invention,
It can be suitably used as an inner and outer wall of a building.

[0002]

2. Description of the Related Art Conventionally, an inorganic cement board has been produced by a papermaking method (Hasheck method, Fourdrind method), extrusion method, etc.
It is manufactured by a wet manufacturing method such as a dehydration press method. However, when a green sheet formed by the above wet method is pressed and formed with a forming press or a forming roll to give an uneven pattern, there is a disadvantage that it is difficult to form a deep and sharp uneven pattern. In addition, a large amount of filtered water is generated at the time of pressure molding, and there is a problem in that if water treatment is performed in consideration of environmental conservation, the production cost increases.

On the other hand, it is possible to give a deep and sharp uneven pattern,
In addition, as a method for producing an inorganic production plate that does not generate filtered water during pressure molding, a dry method for producing a wood chip cement plate has been proposed (for example, Japanese Patent Application Laid-Open No. 3-131554). Since it is used as a reinforcing material, the dimensional stability is poor, and the board is warped or warped, so that it cannot serve as an outer wall. In addition, in order to prevent poor curing due to a curing inhibitor eluted from a piece of wood, it is necessary to add a curing accelerator, and there has been a problem that the material cost is increased. There has been provided a method of using pulp fibers instead of wood chips (see, for example,
3-256560, 63-256561, 56
JP-A-63858), the reinforcing effect of the pulp fiber was not sufficient, and it did not provide an inorganic cement which was lightweight and excellent in strength.

[0004]

DISCLOSURE OF THE INVENTION The present invention not only has a very small amount of voids and defects but also has a good formability that enables formation of a deep uneven pattern. An object of the present invention is to provide an inorganic cement plate having a small change rate of about 0.1% and excellent strength, and a method of producing the cement plate.

[0005]

Means for Solving the Problems The present inventors have found that an inorganic cement board mixed with pulp pre-fibrillated in the presence of an appropriate amount of water can be a cement board that has solved the above-mentioned problems, and has achieved the present invention. completed. That is, in the present invention, 4 to 2 fibers preliminarily defibrated in the presence of water of 2 to 8 times the mass of the pulp are used.
After mixing 0 parts by mass of pulp and an inorganic powder containing Ca and Si components capable of forming calcium silicate hydrate, the pulp and the inorganic powder are mixed so that the total amount becomes 100 parts by mass.
The present invention relates to an inorganic cement board obtained by molding and curing a mixture. Further, the present invention relates to 4 to 20 parts by mass of pulp preliminarily fibrillated by adding water of 2 to 8 times the amount of pulp, and adding an inorganic powder containing Ca and Si components capable of forming calcium silicate to the pulp. After adding and mixing so that the amount becomes 100 parts by mass, the mixture is sprayed to form a mat, and the obtained mat is subjected to pressure molding and then autoclaved to produce an inorganic cement board. About the method. Hereinafter, the present invention will be described in detail.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION In the inorganic cement board of the present invention,
It is characterized in that pulp fibers are used as a reinforcing material, but it is necessary that the pulp fibers are subjected to a defibration treatment in a wet state prior to mixing with other components. Dry pulp defibrated under dry conditions cannot be used. The defibration treatment is performed by a mixer, and at this time, it is necessary to reduce the cohesive force of the fiber by allowing water to exist. The amount of water is 2 to 8 times the mass of the pulp. If the amount of water is less than 2 times the mass of the pulp, the defibration does not proceed sufficiently, which becomes pills in the post-process and remains in the final product. In addition, since there is not enough water for curing the cement, sufficient strength is not generated. On the other hand, if the amount of water is greater than 8 times the mass of the pulp, the effect on fibrillation will peak off, but when molding after mixing other components, not only will molding defects be caused, but also strength will be reduced, As a matter of course, the amount of filtered water requiring harmful substance exclusion treatment increases, which is not preferable.

[0007] The defibration process and the mixing of the raw materials can be performed in separate containers. However, it is preferable that both containers are used in combination, and after the pulp defibration process, other components such as cement are added and mixed in the same container. It is a convenient way.

In the present invention, the type of mixer that can be preferably used for defibration of pulp in a wet state and subsequent mixing with inorganic powder is not limited, but a Plowshare mixer is preferably used as a mixer type. be able to. This mixer is a kind of horizontal cylindrical mixing drum, but a plurality of plough shares (plough share: plow blade type shovel blades) are arranged on a rotating shaft passing through the center of the drum. On the lower inner wall, in the vertical direction, at 45 degrees from the center of the rotation axis,
In the horizontal direction, it is characterized by having an independent drive chopper provided at a position between the adjacent plowshares, so that not only defibration of wet pulp, but also so-called "dama", "Mamako" Is also effective in breaking up aggregates between powders known as "".

The pulp used in the present invention is wood pulp,
Various types such as bamboo pulp, boro pulp, and linter pulp can be used, but wood pulp, which accounts for 90% of the production, is naturally the most preferable. Further, it is not necessary to use virgin pulp, and recovered pulp produced from waste paper has no problem in characteristics and is the most preferable material in consideration of cost. Also, artificial organic fibers such as polypropylene and polyethylene, and artificial inorganic fibers such as glass fiber and carbon fiber can be used alone or in combination with pulp.

[0010] The fiber length of the pulp used in the present invention is not particularly limited, but is 0.5 to 40 mm, preferably 0.5 to 40 mm.
By using the one having a thickness of up to 6 mm, it is possible to obtain a board which is not only excellent in mixing with inorganic powder but also excellent in characteristics.

If the amount of the pulp as the reinforcing material is too small, the reinforcing effect is not exhibited. On the other hand, if the amount is too large, the dimensional stability is reduced and the incombustibility is impaired. 4 to 20% by mass, preferably 6 to
12 mass%.

The inorganic component constituting the siding board of the present invention is a hydraulic inorganic material mainly composed of calcium silicate formed by adding a Si source to cement as a Ca source. As the cement as the Ca source, for example, ordinary Portland, early-strength Portland, alumina, and fly ash cement, and as the Si source, silica powder, such as fly ash, coal ash, silica sand, silica fume, and diatomaceous earth. Can be mentioned. The ratio of the Ca source to the Si source used in the present invention is in the range of 30/70 to 70/30, preferably in the range of 40/60 to 60/40, expressed as a CaO / SiO ₂ molar ratio. It is.

Further, for the purpose of weight reduction, pearlite, shirasu balloon, glass balloon, and expandable thermoplastic plastic beads can be added. Excessive addition of these foams causes a decrease in board strength, so the amount of addition is limited to 20% by mass or less.

The raw material mixture containing the wet pulp mixed by the mixer is firstly spread and deposited on a coal plate by a forming apparatus to form a forming mat. The forming mat uses a press,
It is molded under a pressure of 50 kg / cm ² . When a pattern is to be added to the board surface, a pattern template is stacked on and / or below the forming mat and pressure-formed.

[0015] The obtained molded body is subjected to steam curing at a temperature of 40 to 80 ° C for 6 to 20 hours, and then heated at 160 to 180 ° C and 6 to 10 kg / cm ² in an autoclave.
Cured for up to 10 hours. Then, it is dried to a water content of about 10% to obtain a molded body. The molded article is subjected to a sealer treatment and a surface makeup as required to obtain a product.

[0016]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to specific examples of the production of a molded article by the method of the present invention. (1) Raw materials used The following inorganic and organic raw materials were used.・ Cement: Normal Portland cement ・ Fly ash: Blaine specific surface area 3800 cm ² /
g ・ Silica sand: Blaine specific surface area 4000 cm ² / g ・ Pearlite: Particle size 0.3 mm, bulk specific gravity 0.20 ・ Wet pulp: Water content 30% ・ Dry pulp: Water content 2% or less ・ Wood piece: Width 2-3 mm × Length 200-300mm

(2) Raw Material Mixing A predetermined amount of water was added to 8 parts by mass of pulp or wood beforehand and absorbed, and then put into a plowshare mixer and mixed for 3 minutes to perform defibration. The mixer used was a WB type plowshare mixer manufactured by Taiheiyo Kikai Co., Ltd. equipped with a flat chopper and a standard shovel blade. Next, 60 parts by mass of cement, 12 parts by mass of fly ash, 13 parts by mass of silica powder and 7 parts by mass of pearlite were added and mixed for further 3 minutes to obtain a molding mixture. This mixing method is referred to as an A method. Also, without adding water to the pulp in advance,
The same mixing method (method B) as in method A except that 42 parts by mass of water was added when adding inorganic components such as cement and fly ash was also studied. The mixing ratio of the raw materials and the mixing method are shown in Table 1, but are common to each example except for the amount of water added and the mixing method.

(3) Forming, pressing and curing The mixture is prepared using a known wind forming machine.
A forming mat of 300 mm × 300 mm × 60 mm was formed. The obtained forming mat was set in a press and pressed under a pressure of 30 kg / cm ² to obtain a molded body.

(4) Curing and Drying The pressed compact is heated and cured at 60 ° C. and 100% humidity for 16 hours in a state where it is pressed and constrained by a pressure press to perform primary curing. And then removed from the press. The primary cured body was subjected to secondary curing under the condition of 170 ° C. to obtain a molded body. The molded body was dried until the water content became 8%, and was subjected to characteristic evaluation.

(5) Characteristic evaluation The characteristic evaluation of the specimen was performed by the following method. -Flexural strength: Measured by a method based on JISA 5422 "Ceramic siding". -Dimensional change rate: Measured by a method based on JISA 5422 "Ceramic Siding". -Specific gravity: calculated from the volume and weight calculated from the measured dimensions. -The appearance of the plate was visually observed to determine the surface uniformity. Formability: A cement plate having a groove formed on one side using a pattern shown in Table 1 and having various formability angles was prepared, and the maximum formability angle at which no defect was observed in the groove portion. Indicated by The pattern had a groove depth of 4 mm and a formability angle of every 5 degrees. The results are shown in Table 1 together with the composition.

[0021]

[Table 1]

[0022]

From the results in Table 1, it can be seen that the inorganic cement board of the present invention in which the inorganic powder is added to the pulp which has been kneaded with an appropriate amount of water and defibrated in advance, the uneven distribution of the pulp is suppressed and the appearance is excellent. It turns out that it is excellent in dimensional stability, formability and strength.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C04B 16:02) B28B 11/00 A (72) Inventor Yutada Ito Okiyama, Ogushi, Ogushi, Ube 1-6 Ube Mitsubishi Cement Research Institute Ube Center (72) Inventor Yoshio Matsubara Ube City, Ube City, Ube, Yamaguchi Prefecture 1-6 Ube Mitsubishi Cement Research Institute Ube Center F-term (reference) 4G012 PA04 PA07 PA24 PA26 PA34 PE04 PE06 PE07 4G052 DA01 DB11 DC04 GA02 GA17 GA26 GB41 GC03 4G055 AA02 AB00 BA02 BA43

Claims (4)

[Claims] 1. A pulp of 4 to 20 parts by mass which has been previously defibrated in the presence of water of 2 to 8 times the amount of pulp, and an inorganic powder containing Ca and Si components capable of forming calcium silicate hydrate. Is mixed so that the total amount of pulp and inorganic powder is 100 parts by mass, and then the mixture is molded and cured to obtain an inorganic cement board. 2. The inorganic cement board according to claim 1, wherein the molar ratio of CaO / SiO ₂ in the inorganic powder is 30/70 to 70/30. 3. An inorganic powder containing Ca and Si components capable of forming calcium silicate is added to 4 to 20 parts by mass of pulp preliminarily defibrated by adding water to the pulp in an amount of 2 to 8 parts by mass of pulp. After adding and mixing so that the amount becomes 100 parts by mass, the mixture is sprayed to form a mat, and the obtained mat is subjected to pressure molding and then autoclaved to produce an inorganic cement board. Method. 4. The method for producing an inorganic cement board according to claim 3, wherein the molar ratio of CaO / SiO ₂ in the inorganic powder is 30/70 to 70/30.