JPS6021873A - Manufacture of carbonate gypsum foamed body board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Conventionally, surfactants are used as foaming aids when manufacturing gypsum boards, but types of hemihydrate gypsum, such as α-type hemihydrate gypsum, β-type hemihydrate gypsum, and other brands The surfactant must be selected individually depending on the However, when mixing a polyvinyl alcohol aqueous solution with additives such as gypsum hemihydrate and a hardening accelerator using only a surfactant, the fine air bubbles in the expanded slurry may become coarser or spiky air bubbles may form. It is common for bubbles to occur, resulting in non-uniform bubble density. Therefore, in order to alleviate this phenomenon, it is necessary to increase the expansion coefficient and reduce the specific gravity of the slurry, but this poses a manufacturing problem in that the compressive strength of the gypsum decreases. The present inventor has conducted research in view of this point and has attempted to eliminate the drawbacks of conventional manufacturing methods. More specifically, the bulk specific gravity of the carbonate gypsum foam board manufactured by the method of the present invention is within the range of 1.3 or less, and the various additives used and blended are as follows. can be added selectively.

Various additive substances "gypsum hemihydrate" according to the method of the present invention: α-type or β-type gypsum hemihydrate powder whose chemical formula is CaSO4.1/2H2O. The particle size is preferably 100 mesh or less.

"Surfactant": linear alkyl sulfate, sodium lauryl sulfate, sodium alkylaryl sulfonate, sodium dodecylbenzenesulfonate, sodium lignin sulfonate, alkali metal salts of fatty acids, etc.

"Carbonates of carbonates or bicarbonates": zinc carbonate, ammonium carbonate, cadmium carbonate, potassium carbonate, potassium sodium carbonate, calcium carbonate, chromium carbonate, cobalt carbonate, cobalt carbonate hydroxide, copper carbonate hydroxide, carbonate hydroxide Carbonates such as lead, nickel carbonate hydroxide, magnesium carbonate hydroxide, iron carbonate, copper carbonate, sodium carbonate, sodium potassium carbonate, lead carbonate, nickel carbonate, barium carbonate, magnesium carbonate, calcium carbonate, manganese carbonate, dihydrogen tricarbonate, etc. Carbonates of bicarbonates such as tetraammonium, ammonium bicarbonate, potassium bicarbonate, sodium bicarbonate, potassium magnesium bicarbonate, and lithium bicarbonate.

"Acidic fluoride compounds": silicofluoride salts such as sodium silicofluoride, calcium silicofluoride, potassium silicofluoride, zinc silicofluoride, lead silicofluoride, ammonium silicofluoride, barium silicofluoride salts, Acidic fluoride compounds or acidic fluorides, such as hydrosilicic acid aqueous solution, hydrofluoric acid aqueous solution, acidic sodium fluoride, and acidic potassium fluoride.

"Polyvinyl alcohol": An aqueous polyvinyl alcohol solution prepared to a concentration of 5 to 10% by weight is used, but powdered polyvinyl alcohol can also be used.

"Hardening accelerator": Sulfates such as ammonium sulfate, potassium alum sulfate, magnesium sulfate, silicic substances, and animal colloid substances.

"Waterproofing agent": An aqueous emulsion solution of paraffin or an aqueous emulsion solution of asphalt can be added in an amount of 2% by weight or less in terms of solid content (dry weight) to make it waterproof.

"Fiber materials": glass fibers, silica fibers, carbon fibers,
Any fiber material may be used, such as pulp fiber, polyester fiber, propylene fiber, and metal fiber.

"Silicate": Calcium silicate salts (e.g. calcium metasilicate and dicalcium silicate, etc.), barium silicate salts, lead silicate salts,
Magnesium silicate salt, manganese silicate salt, magnesium calcium metasilicate salt, etc.

"Chloride": Calcium chloride, barium chloride, magnesium chloride, lead chloride, ammonium chloride, etc.

"Synthetic resin emulsion aqueous solution": polyvinyl acetate emulsion aqueous solution, acrylic acid ester copolymer emulsion aqueous solution, polystyrene emulsion aqueous solution, styrene-butadiene copolymer emulsion aqueous solution, polyvinyl alcohol vinyl chloride copolymer emulsion aqueous solution, other synthesis Any aqueous emulsion solution of resin may be used.

The gypsum board base paper used in the method of the present invention contains gypsum board base paper (paper thickness, 0.6 mm or less), asbestos paper (pulp content 20% or less), glass fiber cloth, other craft papers, and glass fibers. You can use Japanese paper, Western paper, etc. The thickness of carbonate gypsum foam board is of course around 1.6 mm, but also 3 mm, 6 mm, 9 mm, 12 mm, 15 mm, 20 mm, and 6 mm.
It can be manufactured by molding boards of 0 mm, 100 mm, 120 mm, etc. In that case, if necessary, it is also possible to manufacture foamed gypsum slurry by pouring it between two or more sheets of paper, for example between three sheets of paper, and forming it into a board shape. (eg polyester fiber cloth) can also be used. Next, the method of the present invention will be explained with reference to examples.

Example 1 Formulation β-type gypsum hemihydrate 100 parts by weight Linear alkyl sulfate 0.08 Calcium carbonate with an average particle size of 0.15 microns 0.4 10% calcium silicofluoride aqueous solution 3.6 5% Polyvinyl alcohol aqueous solution 20 Ammonium sulfate 1.2 Water 50 The additives consisting of the above are homogeneously stirred or mixed within 10 seconds in a mixer to form a highly fluid solution containing countless fine carbon dioxide gas bubbles. After creating a foamed gypsum slurry, it is poured into a mold made of two sheets of gypsum board base paper and cured in 8 minutes. After drying at a temperature of 150°C, a molded product of carbonate gypsum foam board with a thickness of 12 mm and a bulk specific gravity of 0.84 is produced. was manufactured.

Example 2 Formulation β-type gypsum hemihydrate 100 parts by weight Linear alkyl sulfate 0.08 Calcium carbonate with an average particle size of 0.15 microns 0.4 10% calcium silifluoride aqueous solution 3.6 5% Polyvinyl alcohol aqueous solution 20 〃 Ammonium sulfate 1.3 〃 Glass fiber 0.4 〃 Water 50 〃 The same operation as in Example 1 was carried out, and the mixture was poured into a mold made of two glass fiber cloths and cured for 9 minutes, and heated at 150°C. After drying at temperature, a carbonate gypsum foam board with a thickness of 3 mm and a bulk specific gravity of 0.83 was produced. Example 2 shows that fibrous materials such as glass fibers can be used in combination.

Example 3 Formulation β-type gypsum hemihydrate 100 parts by weight Linear alkyl sulfate 0.08 Calcium carbonate with an average particle size of 0.15 microns 1.0 10% aqueous sodium silicofluoride solution 10.3 10% Calcium metasilicate aqueous solution 1.2 〃 Calcium chloride (CaCl2.2H2O) 0.8 〃 5% polyvinyl alcohol aqueous solution 20 〃 15% vinyl acetate emulsion aqueous solution 10 〃 Ammonium sulfate 1.4 〃 Glass fiber 0.4 parts by weight Water 42 〃 Perform the same work as in Example 1, pour into two kraft paper molds, harden in 8 minutes, dry at 150°C, and foam carbonate gypsum with a thickness of 60 mm and a bulk specific gravity of 0.65. Manufactured the body board. The foaming reaction is as follows.

Na2SiF6+CaSiO3+CaCO3+CaCl
2+2H2O→3CaF2↓+2H2SiO3↓+2N
aCl+CO2↑Example 3 shows that an aqueous emulsion solution such as an aqueous vinyl acetate emulsion solution or an aqueous emulsion solution of a synthetic resin can be used in combination.

As detailed above, according to the present invention, it is possible to economically and inexpensively control carbonate gypsum foam board containing fine air bubbles that have good adhesion between gypsum board base paper or paper and gypsum. Its industrial utility value is wide-ranging.

Patent applicant: Kenichi Abe

Claims (1)

[Claims] 1. The main raw material is α-type or β-type gypsum hemihydrate, and the amount of water mixed with it is a surfactant, carbonate or bicarbonate, acidic fluoride compound, polyvinyl alcohol, hardening accelerator, and gypsum hemihydrate. of water and stirred or mixed homogeneously in a mixer to create a highly fluid gypsum foam slurry containing countless microscopic carbon dioxide gas bubbles, which is then poured between gypsum board base paper or paper to form a board. A method for producing a carbonate gypsum foam board, which comprises molding the board, then curing and drying it.