JPS5918143A - Manufacture of foamed gypsum 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 The present invention relates to a method for manufacturing foamed gypsum board made from α-type hemihydrate gypsum or β-type hemihydrate gypsum slurry. Generally, gypsum boards manufactured by using foaming aids such as surfactants in gypsum slurry are inexpensive, but they sometimes become soft when moisture penetrates. The cause of this softening is that when a certain amount of aqueous polymer solution or synthetic resin emulsion is mixed with the gypsum slurry together with a foaming aid, small gas bubbles are inevitably released into the gypsum slurry before the gypsum hardens. This is because it dissolves in an aqueous solution and becomes coarse, resulting in poor adhesion with insufficient adhesion to the gypsum board cloth, especially when a hydrophilic surfactant is used as a foaming aid. Penetration of moisture from the outside is significant due to capillary action. The present invention eliminates the drawbacks of conventional manufacturing methods and products, and provides a foamed gypsum board manufactured by an inexpensive and simple manufacturing method. The foamed gypsum board produced by the method of the present invention has a bulk specific gravity of 0.3 or more, and is a heavy and thick board.The various additives to be mixed are as follows, but these may be used selectively. It can be added.

Various additive substances, gypsum hemihydrate, by the method of the present invention: α-type gypsum hemihydrate, whose chemical formula is CaSO4.1/2H2O, and which has a small amount of mixed water.
or β-type gypsum hemihydrate powder, particle size is
Preferably less than 100 mesh
Yes.

Hydrophobic stearate: Calcium stearate
barium stearate, stear
Lead phosphate, manganese stearate,
Hydrophobic stearates such as nickel stearate, aluminum stearate, tin stearate, cadmium stearate, zinc stearate, cobalt stearate, zirconium stearate,
Excludes water-soluble alkali metal stearates.

Carbonate or bicarbonate: calcium carbonate, carbonate
lium, magnesium carbonate, etc. in water.
whereas insoluble carbonate, water soluble
Sodium carbonate, the bicarbonates sodium bicarbonate, ammonium bicarbonate, and other carbonates such as zinc carbonate, lead carbonate, nickel carbonate, manganese carbonate, and iron carbonate can also be used.

Basic oxides: calcium oxide, burr oxide
It is also possible to use a combination of aluminum, magnesium oxide, potassium oxide, sodium oxide, and strong basic oxides.

Acidic fluoride: Hydrofluoric acid (56%) aqueous solution, silica
Hydrochloric acid aqueous solution (40%), silicon fluoride
Lucium, barium silicofluoride, silicofluoride
Magnesium, iron silicofluoride, lead silicofluoride, zinc silicofluoride, nickel silicofluoride, manganese silicofluoride, sodium silicofluoride, acidic sodium fluoride.

Hardening accelerator: ammonium sulfate, potassium sulfate,
Sulfuric acid such as alum and magnesium sulfate
salts, silicic substances (e.g. metasilicic acid 15
, colloidal silicic acid aqueous solution) and other animal dicalcium substances, etc. These substances are used as hardening accelerators for α-type or β-type gypsum hemihydrate.

Polyvinyl alcohol aqueous solution: gypsum foam board
When producing a board, a 5-10% aqueous solution prepared in advance can be used.

Synthetic resin emulsion: polyvinyl acetate emulsion
Lusion, acrylic acid ester copolymer
Combined emulsion, polystyrene
Aqueous solutions such as emulsions, styrene-butadiene copolymer emulsions, and polyvinyl alcohol vinyl chloride copolymer emulsions can be used.

Waterproofing agent: paraffin emulsion or as
Falt's emulsion aqueous solution, book
The foamed gypsum board of the invented method is α type or
or β-type hemihydrate gypsum, solid content 15
Waterproofing can be achieved by adding less than 2% of the waterproofing agent.

In this case, a synthetic resin emulsion
Fiber materials that may be used in conjunction with aqueous solutions: Glass fiber, alkali-resistant glass fiber
Silica fiber, carbon fiber, asbestos fiber,
Amosite fibers, pulp fibers, nylon fibers, synthetic fibers such as propylene fibers, metal fibers, and any other fibrous material may be used.

The procedure for mixing or stirring various additive substances according to the method of the present invention is to dissolve or uniformly disperse an emulsion aqueous solution of acidic fluoride, curing accelerator, and synthetic resin in water equivalent to the amount of water absorbed by α-type or β-type hemihydrate gypsum. A diluted aqueous solution is prepared, and then a powder prepared by uniformly mixing and dispersing hydrophobic stearate, carbonate or bicarbonate, and basic oxide is added to α-type or β-type gypsum hemihydrate powder. Mixing or stirring within 5 seconds to create a foamed gypsum slurry containing countless small air bubbles from highly fluid gypsum slurry, which is then poured into a formwork fitted with gypsum board cloth. It is characterized by being cured within 5 to 10 minutes after molding. Of course, it is possible to adjust the curing time to less than 5 minutes or even more than 10 minutes. 40~ after curing
The product is dried at a temperature of around 170°C. The original fabric for gypsum board used can be a fabric for gypsum board that has been waterproofed or a fabric for gypsum board that has not been waterproofed. Cotton cloth, polyester fiber cloth, nylon fiber, polypropylene fiber cloth, cotton polyester blend fiber cloth, cotton nylon fiber blend fiber cloth, other leather cloth, and heat-resistant synthetic leather cloth can also be used as the raw material for the board. can. Cloths made of other fibers can be used as raw cloth for boards. The decorative surface of a foamed gypsum board produced by molding using the original board fabric or the surface of the original fabric can be treated with a resin and made sufficiently waterproof to be used as an exterior decorative board. Next, the method of the present invention will be explained with reference to Examples.

Example 1 Combination of various additives β-type gypsum hemihydrate 100 parts by weight Calcium stearate 0.015 Average particle size 1.3 microns Calcium carbonate
0.20 parts by weight Calcium oxide 0.20 40% aqueous hydrosilicic acid fluoride solution 1.01 1.3 micron calcium carbonate 0.28 Vinyl acetate emulsion 15
% aqueous solution 12
．． 0 Ammonium sulfate 1.2
〃Wed 58.0
[With the blending ratios of various additives shown in Example 1, first, 0.015 parts by weight of hydrophobic calcium stearate and 1 part by weight of calcium carbonate with an average particle size of 1.3 microns were added to 100 parts by weight of β-type hemihydrate gypsum. Calcium oxide is prepared by uniformly dispersing and mixing 0.20 g of calcium oxide which has been finely ground after being fired to 0.000°C or above. Next, the water absorption amount of β-type hemihydrate gypsum is 58.0
1.01 parts by weight of a 40% aqueous hydrosilicofluoric acid solution and 0.28 parts by weight of calcium carbonate having an average particle size of 1.3 micrometers were added to the parts by weight, and after stirring, a chemical reaction was sufficiently carried out to produce calcium silicofluoride. After that, vinyl acetate emulsion 15%
Add 12.0 parts by weight of the aqueous solution, then add 1.2 parts by weight of ammonium sulfate powder and stir well to dissolve. Into the prepared mixed aqueous solution, the previously prepared hydrophobic calcium stearate and 1.3 micron calcium carbonate are added. A foamed gypsum slurry with good fluidity obtained by adding β-type hemihydrate gypsum powder evenly dispersed and mixed with calcium oxide and performing a mixing or stirring operation within 5 seconds was attached to two sheets of original board fabric. After pouring into a mold and drying at a temperature of around 170° C. for 42 minutes for curing, the foaming reaction of the product with a bubble size of 0.5 mm or less, a bulk specific gravity of 0.78, and a thickness of 40 mm is as follows.

CaSiF6+CaO+CaCO3+H2O→3CaF
2↓+H2SiO3↓+CO2↑The two board fabrics used in Example 1 were fabrics mixed with cotton and polyester fibers.

Example 2 Combination of various additives β-type gypsum hemihydrate 100 parts by weight Magnesium stearate 0.016 Average particle size 1.3 microns Calcium carbonate
0.25 Glass fiber
0.20 Calcium oxide
0.20 〃40% aqueous hydrosilicofluoric acid solution 1.12 〃1.3 micron calcium carbonate 0.31 〃vinyl acetate alcohol aqueous solution (
5%) 1
0 Ammonium sulfate 1.2
〃Wed 48
〃A foamed gypsum slurry with good fluidity obtained by performing the same operation method as in Example 1 was poured into a mold with two sheets of original board fabric attached, and cured at around 170°C for 4 to 6 minutes. After drying at temperature, the bubble size is 0.3 mm or less, and the bulk specific gravity of the product is 0.77, making it an excellent adhesive material for board fabrics.40
Produced millimeter-thick foamed gypsum board. The foamed gypsum board produced by the method of the present invention can not only be used to produce 9 mm thick, 12 mm thick, 15 mm thick, and 20 mm thick gypsum board made by the conventional method, but also 60 mm thick, 100 mm thick, etc. It is something.

The present invention is a divisional patent application for a method of manufacturing gypsum foam, which is the title of patent application No. 6412 of 1982, and is an improvement on the original patent application in that the application has been expanded.

Patent applicant Ken Abe■

Claims (1)

[Claims] 1. Gypsum hemihydrate is the main raw material, along with hydrophobic stearate, carbonate or bicarbonate, basic oxide, acid fluoride, emulsion of synthetic resin, hardening accelerator and water absorption of gypsum hemihydrate. A method for manufacturing a foamed gypsum board, which comprises adding a large amount of water and mixing or stirring, then pouring a highly fluid foamed gypsum slurry into a mold made of gypsum board cloth, and then hardening and drying the slurry.