Compositions: coating or plastic – Coating or plastic compositions – Inorganic settable ingredient containing
Patent
1998-02-18
2000-10-31
Aftergut, Karen
Compositions: coating or plastic
Coating or plastic compositions
Inorganic settable ingredient containing
106679, 1062866, 1062871, 264 86, 264 87, 264333, B28B 114, B28B 126, C04B 3800
Patent
active
061396206
DESCRIPTION:
BRIEF SUMMARY
INDUSTRIAL FIELD OF THE INVENTION
The present invention relates to a method of manufacturing a calcium silicate board and the calcium silicate board obtained by the method.
RELATED ART AND PROBLEMS
Conventionally, calcium silicate boards have been widely used for building materials, in particular, for interior materials because of such characteristics as being light, excellent in workability and dimensional stability, and non-combustible.
Calcium silicate boards used for building material are formed using a forming process such as the Hatschek sheet machine process a press mold process or a mono-layer mold process and are manufactured as follows: a molded body is formed from a calcareous material, a silica containing material, reinforcing fibers and fillers, such as light-weight aggregate, then, in general, subjected to curing reaction by saturated water vapor in a pressure container. Generally, the bulk specific gravity of the calcium silicate boards is in a range of from 0.7 to 1.2.
Since calcium silicate boards are used as an interior material, such as ceiling materials and wall materials, lightening the boards is desirable, however, according to the above methods it is necessary to mix a considerable amount of light-weight aggregate so as to achieve a bulk specific gravity of 0.5 to 0.8, resulting in a decrease in the specific strength of the boards.
In particular, when a light-weight calcium silicate board having a bulk specific gravity of 1.0 or less is manufactured according to the Hatschek sheet machine process, the following problems sometimes occur: because of the low strength and large water content of the molded body before hydrothermal reaction, the redundant water thermally expands during hydrothermal reaction or the vapor pressure increases, resulting in interlayer peeling or bursting.
To avoid the above problems, in some methods, a molded body is pressed after forming then subjected to hydrothermal reaction or a molded body is tightened by a turn-buckle during the hydrothermal reaction. However, in accordance with these methods, such problems occur that the bulk specific gravity increases and more labor is required for manufacturing.
In addition, Japanese Patent Laid-Open No. 6-287083 discloses a method of removing the redundant water, though this method cannot be commonly used because a specific pressure container or a vapor heater is necessary.
Further, conventionally, a material slurry containing a calcareous material and an amorphous silica containing material is heated at a normal pressure for gelation so as to achieve a light-weight board. However, according to this method, the board strength is inevitably reduced, and further, the material is so soft that it is readily shaved during polishing. Therefore, cellulose fibers become extremely fuzzy such that the surface smoothness is impaired when the board is used after coating.
Moreover, another method is disclosed in Japanese Patent Laid-Open Nos. 52-105926 and 52-135330, wherein calcium silicate boards exhibiting excellent strength are obtained by adding a xontlite slurry, which is a kind of calcium silicate hydrate, or a crystalline calcium slurry. Since productivity decreases according to these methods, improvement is required from a viewpoint of manufacturing costs.
Additionally, in Japanese Patent Laid-Open Nos. 5-213657 and 7-41354, the inventors of the present invention have already disclosed a method of adding both a gelatinized slurry, comprising a calcareous material and an amorphous silica containing material, and a crystalline calcium silicate hydrate slurry. However, in the case of a board laminated by the Hatschek sheet machine process, some problems, such as interlayer peeling or bursting, occur even in this method of adding gels.
Furthermore, Japanese Patent Publication No. 58-30259 discloses a method of manufacturing a calcium silicate molded body characterized by the following: a silica containing material and a calcareous material are dispersed in water of which the amount by weight is 15 times or more than that
REFERENCES:
patent: 4128434 (1978-12-01), Pusch
patent: 4144121 (1979-03-01), Otouma et al.
Patent Abstracts of Japan, vol. 018, No. 625 (C-1279), Nov. 29, 1994 (11-29-94) & JP 06 239672 A (NKK Corp), Aug. 30, 1994 (08-30-1994) *Abstract*.
Patent Abstracts of Japan, vol., 017, No. 436 (C-1096), Aug. 12, 1993 (08-12-1993) & JP 05 097 498 A (Nichias Corp), Apr. 20, 1993 (04-20-93) *Abstract*.
Asami Takuya
Iwanaga Tomoki
Oda Masaaki
Oshio Yasuhide
Sakiyama Masato
Aftergut Karen
ASK Corporation
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