JPS5939283B2 - Pseudo-laminated multicellular gypsum molded product and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pseudo-laminated multicellular gypsum molded product that is lightweight, has high strength, and exhibits a good appearance, and a method for producing the same.

Here, "pseudo-laminated" is a term that expresses the characteristics of the molded product of the present invention, as defined below.

That is, the laminated molded product obtained by the manufacturing method of the present invention has a fibrous layer 1 on the surface, and a gypsum skin layer 2 in contact with the inside, as the structure is schematically shown in FIG.
The gypsum skin layer 2 is a foam-free layer that does not substantially contain air bubbles, and further has a structure in which a gypsum porous core portion 3 is located inside the gypsum skin layer 2. This structure is similar to a laminate made by bonding each layer and part using a known method, but unlike known laminates, the structure of each layer and part is continuous. Therefore, this is called a "pseudo-laminated" structure. This pseudo-laminated structure consists of a fibrous material containing a water-soluble chelating agent having a -N-C (=5) structure or an N,N-dimethylene carboxylate structure, and a water-soluble material containing a blowing agent. Since it is made by integrally molding hard gypsum with a water mixture, the adhesive strength between the fibrous layer and the gypsum skin layer as well as between the gypsum skin layer and the gypsum core is extremely high. A known multicellular hardened gypsum material, so-called foamed gypsum, has attracted attention as a lightweight material and a heat insulating material, but it has disadvantages in that it has a poor appearance and a brittle surface, making it inconvenient to handle. If such a porous hardened gypsum body could be covered with paper or the like as is done with ordinary gypsum boards, the above-mentioned drawbacks would be overcome and the commercial value of the porous hardened gypsum body would be improved. However, since known multicellular gypsum hardened bodies have poor adhesion to paper, cloth, etc., it would be difficult to cover them with paper, cloth, etc. at the same time as the gypsum hardens, like a normal gypsum board. If coating was absolutely desired, a complicated and time-consuming method had to be used, and the appearance of the product and the durability of the coating were unsatisfactory, so it was necessary to develop a good coating method using integral molding. It was wanted. The object of the present invention is to provide a method for producing a porous hardened gypsum body covered with paper, cloth, etc., which does not have the above-mentioned drawbacks.

That is, according to the present invention, a fibrous material containing a water-soluble chelating agent having an -N-C (=5)- structure or an N,N-dimethylenecarboxylate structure and a blowing agent are contained. It is made by contacting hydraulic gypsum with a water mixture and molding it into one piece. Upon contact, the water-soluble chelating agent rapidly penetrates into the gypsum water mixture, suppressing foaming of the fibrous material layer and the gypsum layer in its vicinity. forms a thick skin layer. In addition, as the amount of penetration decreases, it continuously moves from the skin layer to the core part, and microscopically, the structure of each layer and part becomes continuous. Therefore, the bonding strength between the fibrous layer, the gypsum skin layer, and the gypsum core is high, and a molded product with high strength can be obtained. This fibrous material is preferably water-wettable, and any fibrous material such as a paper-like material or a cloth-like material can be used.

Paper-like materials include fiber base paper and synthetic paper that wets easily with water, and cloth-like materials include recycled fibers in the form of woven fabrics and non-woven fabrics, natural fibers such as cotton and wool, glass fibers, and asbestos. , inorganic fibers such as gypsum fibers, and synthetic fibers with good water wettability such as polyvinyl alcohol and polyamide can also be used. As the chelating agent used in this invention, a nitrogen-containing water-soluble chelating agent is preferable, and a water-soluble chelating agent having a -N-C(=S) structure or an N,N-dimethylenecarboxylate structure is particularly preferable.

Examples of water-soluble chelating agents having a -N-C (=S) structure include alkali metal salts of dialkyldithiocarbamic acids, thiourea, and the like. Here, alkyl refers to methyl, ethyl, etc., and alkali metal refers to sodium, potassium, etc. Also, what is an example of a water-soluble chelating agent with an N,N-dimethylenecarboxylate structure? When you get it, 1, 2
-Cyclohexanediaminetetraacetic acid, diethylenetriaminepentaacetic acid, ethylenediaminetetraacetic acid, ethylene glycol bis(β-aminoethyl ether) N, N, Nl, N'
Tetrasodium tetraacetate, ethylenediamine-N,N',
These include salts with ammonium, alkali metals, alkaline earth metals, or mixtures thereof, such as Nl triacetic acid, iminodiacetic acid, and nitrilotriacetic acid. What is hydraulic gypsum?
These include β-hemihydrate gypsum, α-hemihydrate gypsum, and soluble anhydrous gypsum.

As the blowing agent, various known gas generating agents can be used, but hydrogen peroxide is a preferred blowing agent.

Hydrogen peroxide is preferably added as a hydrogen peroxide solution, and the amount added is generally 0.4 to 10 parts by weight per 100 parts by weight of hydraulic gypsum. The amount of water is hydraulic gypsum,
The mixture of foaming material and water (hereinafter referred to as the molded product stock solution) may be adjusted to a range in which the mixture exhibits fluidity that allows casting.

For example, when β-hemihydrate gypsum is used as hydraulic gypsum, it is desirable to use 40 to 100 parts by weight of water per 100 parts by weight of hydraulic gypsum. In this invention, a hydraulic gypsum hardening regulator may be added to the molded product stock solution. Known hardening retarders such as citric acid or its ammonium salt or alkali metal salt, boric acid, phosphoric acid, or their alkali metal salts can be used;
Since ammonia is effective in controlling both the setting time of gypsum and the rate of decomposition of hydrogen peroxide, it is preferable to use ammonia alone or in combination with known setting modifiers. Ammonia is added in the form of ammonia water, ammonia gas, etc. Addition amount is hydraulic gypsum 100
The pH of the molded product stock solution is 1 when the amount is 0.2 parts by weight or more.
If it is 0 or more, it is effective, and especially if it is 1 part by weight or more and the pH is 10.5 or more, there is a remarkable effect. In addition to this invention, an inorganic filler such as silica or an organic filler such as a valve may be added to the stock solution of the molded product for reinforcement.

Further, in order to provide water proofing properties, a known water repellent such as an aqueous emulsion of solid paraffin may be added to the stock solution of the molded product.

Adding a surfactant such as a nonionic surfactant to the molded product stock solution is more effective in dispersing and stabilizing air bubbles.

The amount added is 0.00 parts by weight per 100 parts by weight of hydraulic gypsum.
0.005 to 0.1 part by weight is preferred. Various methods can be considered for producing the pseudo-laminated multicellular gypsum molded article of the present invention. →1j shows that a liquid containing hydraulic gypsum, hydrogen peroxide, and water, that is, a stock solution for a molded product, has a 1N-(C-S) structure or an N,N-dimethylenecarboxylic acid salt on at least one surface of the liquid material containing hydraulic gypsum, hydrogen peroxide, and water. A water-soluble chelating agent with a structure (hereinafter referred to as
There is a method in which a fibrous material containing a chelating agent (hereinafter referred to as the chelating agent) is brought into contact with the fibrous material and molded. The fibrous material containing the chelating agent can be prepared by impregnating the fibrous material with an aqueous solution of the chelating agent in advance, by applying or spraying the chelating agent onto the fibrous material placed in a mold, or by adding it to the undiluted solution of the molded product. It is prepared by spraying or impregnating the above-mentioned chelating agent on top of the fibrous material, or by applying or spraying the above-mentioned chelating agent into the mold in advance, and then placing the fibrous material thereon. . The pseudo-laminated multicellular gypsum molded product of the present invention includes not only those in which a fibrous layer is present on one side of the multicellular gypsum hardened product, but also those in which fibrous layers are present on both sides of the multicellular gypsum hardened product. Also included are those with a so-called sandwich structure in which porous gypsum hardened bodies are present on both sides of a fibrous layer.

Next, the present invention will be specifically explained by giving examples.

Also, for comparison, an example in which the above chelating agent is not used is given as a control example. Example 1β Hemihydrate gypsum 1330V, 28% ammonia water 108f and water 110
0t was mixed.

Separately, β hemihydrate gypsum 170f and 30% hydrogen peroxide solution 16
01 and a commercially available 1% aqueous nonionic surfactant solution 51 were mixed. The above two mixtures were mixed and the stock solution of the molded article was poured onto paper impregnated with a 9% aqueous thiourea solution. After the plaster had hardened, it was air-dried overnight and then further dried at 50°C for 5 hours.The bulk density of the multicellular hardened product was 0.41t/
It was d. The porous gypsum hardened material strongly adheres to the paper impregnated with thiourea, and a gypsum skin layer with a thickness of approximately 2wn, which does not contain any air bubbles, is formed between the paper and the hardened material. It was detected that the paper residue and skin layer adhered to the molded article contained 0.3% and 0.1% thiourea, respectively.

Symmetrical Example 1 The experiment was repeated as in Example 1, except that instead of impregnating with an aqueous solution of thiourea, water-impregnated paper was used.

No gypsum skin layer was observed in the obtained porous gypsum hardened body.

Furthermore, the adhesion between the porous gypsum hardened material and the paper was poor, and the paper peeled off naturally.

Example 2 28 containing β hemihydrate gypsum 790f and citric acid 0.331
(fl) Ammonia water 560f was mixed.

Separately, β hemihydrate gypsum 110V and 30% hydrogen peroxide solution 10V
0t and a 1% aqueous solution 31 of a commercially available nonionic surfactant were mixed. Mix the above two types of mixture, pour it into a mold, immediately place water-absorbent paper on its surface, and add a 5% by weight aqueous solution of thiourea. was sprayed at a rate of 8α per 100c1i of paper. After the plaster had hardened, it was dried at 60°C for 3 hours. The bulk density of the porous gypsum hardened material is 0.48t/Cri
It was l. The cured product adhered to the paper placed on it so strongly that it could not be separated, and a gypsum skin layer with a thickness of 1.5 w1 nm and containing no air bubbles was formed between the cured product and the paper. Example 3 β Hemihydrate gypsum 462t and citric acid 0
．． 28 (: fl) containing 22 tons and 337 tons of aqueous ammonia were mixed.

Separately, 66t of β-hemihydrate gypsum and 601t of 30% hydrogen peroxide solution.
and 1.8 t of a 1% aqueous solution of a commercially available nonionic surfactant were mixed. The above two mixtures were poured into a mold lined with paper impregnated in advance with a 9% by weight aqueous solution of sodium diethyldithiocarbamate.

After the plaster had hardened, it was removed from the mold and dried at 60°C for 3 hours. The bulk density of the porous gypsum hardened material is 0.5t
It was /d. When this porous gypsum molded product was cut, the porous hardened material contained many spherical bubbles with an average diameter of about 2 TvrL, and when in contact with the paper, it had a thickness of about 1 mm. A gypsum skin layer was formed. Example 4 After injecting a molded product stock solution with the same composition as that used in Example 2 into a mold, a coarse glass fiber cloth was immediately placed on the surface of the mold, and 5% by weight of thiourea and a commercially available non-woven fabric were poured into the mold. Water containing 0.05% by weight of an ionic surfactant was added per 100 cd of fabric (
It was sprayed at a rate of t.

After the plaster had hardened, it was dried at 60°C for 3 hours. In the obtained porous gypsum molded article, a gypsum skin layer was formed between the cloth and the porous gypsum hardened body, and the cloth and the gypsum hardened body were well bonded. Example 5 A rayon wallpaper material that had been pre-impregnated with a 9% thiourea aqueous solution was placed on a mold, and a molded product stock solution having the same composition as used in Example 1 was poured into the mold. After the plaster had hardened, it was air dried overnight and then dried at 50°C for 3 hours.

Rayon wallpaper adheres well to cellular gypsum hardened material.
In addition, a gypsum skin layer was formed between the wallpaper and the cured product. Example 6 Two mixtures with the same composition as in Example 3 were prepared.

Lay decorative printing paper lined with Japanese paper inside the mold with the Japanese paper facing up, and apply a 9% by weight aqueous solution of sodium dimethyldithiocarminate to the paper 100c! The paper in the mold was sprayed at a rate of 6α per il, and a molded product stock solution containing the above two mixtures was injected into the paper. After the gypsum hardens, it is removed from the mold and dried at 50°C for 5 hours.The molded product has decorative paper that adheres well to the multicellular hardened gypsum material.
A gypsum skin layer approximately 1 m thick was formed between the paper and the cured body. Example 7 Two sheets of paper impregnated with a 9% thiourea aqueous solution were prepared.

One of the sheets was placed in a mold, a stock solution having the same composition as in Example 2 was poured into it, and the remaining sheet of impregnated paper was placed on top of it. After the plaster has hardened, remove it from the mold and heat it at 60℃ for 6 hours.
In the molded product obtained by drying for a long time, the paper was well adhered to both surfaces of the multicellular hardened gypsum body, and a gypsum skin layer was formed between the paper and the hardened body. Example 8 A mixture of 231 t of β-hemihydrate gypsum and 168 V of 28% aqueous ammonia was prepared.

Beta hemihydrate gypsum 33V and 30% hydrogen peroxide solution 30? and 0.9 g of water containing 1% of a commercially available nonionic surfactant. A molded product stock solution containing the above two mixtures was injected into a mold lined with paper impregnated with a 5% aqueous solution of disodium iminodiacetate.

After the plaster has hardened, it is removed from the mold and left to air dry overnight.
The molded product obtained by further drying at 50°C for 5 hours had a bulk density of 0.48 V/Cd of the porous gypsum hardened material, and the adhesion between the paper and the hardened material was good. A gypsum skin layer with a thickness of about 1 Tfrtt was formed between the two. Symmetrical Example 2 A molded article obtained in the same manner as in Example 8 except that paper impregnated with purified water was used instead of disodium iminodiacetate had a bulk density of a porous gypsum hardened product of 0.52 V/Cd.
However, the adhesion between the paper and the cured product was poor, and the paper suddenly peeled off.

Further, no formation of a gypsum skin layer was observed between the paper and the cured product. Example 9 28% containing β hemihydrate gypsum 7901 and citric acid 0.2r
60 t of ammonia water and 500 t of water were mixed.

Separately, 110y of β hemihydrate gypsum and 80y of 30% hydrogen peroxide solution
mixed with. After mixing the above two types of mixed liquids and pouring them into the mold, immediately place water-absorbent paper on top of the mixture, and add 5 (F6 aqueous solution of tetrasodium ethylenediaminetetraacetate) to
The ratio was 8α per 0cd. After the gypsum hardens, it is removed from the mold and dried at 60°C for 3 hours. The resulting molded product has a bulk density of 0.46 tons of porous hardened gypsum.
/i, the cured product adhered well to the paper, and a gypsum skin layer with a thickness of about 1 m was formed at the portion where the cured product of the porous stone was in contact with the paper. Example 10 28% containing 470t of β hemihydrate gypsum and 0.1t of citric acid
340 y of ammonia water was mixed.

Separately, β-hemihydrate gypsum 801, 60 f of a 30% hydrogen peroxide solution, and 1.2 v of a 1% aqueous solution of a commercially available nonionic surfactant were mixed. A molded product stock solution containing the above two mixtures was injected into a mold lined with a rayon nonwoven fabric impregnated with a 5% aqueous solution of trisodium nitrilotriacetate. After the plaster hardens, it is removed from the mold and dried at 60°C for 3 hours.The resulting molded product has a bulk density of 0.5.
t/(7I1), and the adhesion between the cured product and the nonwoven fabric was good, and a gypsum skin layer with a thickness of about 1.5 m was formed at the portion where the porous gypsum cured product was in contact with the nonwoven fabric. Example 11 Two mixtures of the same composition as used in Example 8 were prepared.

A molded product stock solution containing the above two mixtures was poured into a mold lined with a coarse glass fiber cloth impregnated with a 5% ammonia aqueous solution of 5% disodium ethylenediaminetetraacetic acid and diammonium.

After the plaster has hardened, it is removed from the mold and left to air dry overnight.
The molded product obtained by further drying at VC50°C for 5 hours had good adhesion between the plaster and the glass fiber cloth, and a gypsum skin layer was formed at the part where the porous gypsum hardened material was in contact with the glass fiber cloth. . Example 12 To demonstrate that a variety of water-soluble chelating agents can be used, two mixtures having the same composition as in Example 8 were prepared.

5 of 10% ethylenediaminetetraacetic acid tetraammonium salt
(fl) Ammonia aqueous solution, 10% ethylene glycol pis(β-aminoethyl ether) N, N, N', N'
an aqueous solution of tetrasodium tetraacetate, a 10% aqueous solution of pentasodium diethylenetriaminepentaacetate, and a 5% aqueous solution of 1,
Formworks lined with paper each impregnated with an aqueous solution of tetrasodium 2-cyclohexanediaminetetraacetate were prepared.

A molded product stock solution obtained by mixing the above two types of mixtures was poured into each mold. After the plaster had hardened, it was removed from the form, air-dried overnight, and then dried at 50°C for 5 hours.The resulting molded products had good adhesion between each impregnated paper and the plaster, and were considered to be porous hardened plaster. A gypsum skin layer was formed where the surface contacted the paper. As is clear from the above description, in this invention, by using a water-soluble chelating agent when integrally molding a fibrous material and a plaster composition containing a foaming agent, it is possible to together form several thick skin layers with virtually no air bubbles, and the skin layers continuously transfer to the core, so that the fibrous layer, the skin layer, and the core are The bonding strength is high, and a molded product with high strength can be obtained.

In other words, the molded product obtained by the manufacturing method of the present invention has a good appearance because the surface of the porous gypsum hardened body, which has a brittle and easily crumbling surface, is firmly covered with a fibrous material layer. Moreover, it has great strength and flexibility, and is convenient for handling such as transportation. Moreover, according to the present invention, such a molded article requires complicated lamination work because of the fibrous material containing a water-soluble chelating agent and the water-soluble molded hard gypsum composition containing a foaming agent. Not only can molded products of any shape and size be manufactured at low cost, but also molded products of arbitrary shapes and sizes can be manufactured at low cost.

[Brief explanation of the drawing]

The drawings schematically represent the structure of a cellular gypsum molded product obtained by the manufacturing method of the present invention. 1: Fibrous layer, 2: Gypsum skin layer, 3: Gypsum porous core.

Claims (1)

[Claims] 1 - Contacting a fibrous material containing a water-soluble chelating agent having a -N-C(=S)- structure or an N,N-dimethylene carboxylate structure with an aqueous mixture of hydraulic gypsum containing a blowing agent. A method for producing a pseudo-laminated porous stone product characterized by integral molding.