JPS6141877B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention provides a foamed slurry obtained by adding a composition mainly composed of inorganic powder, inorganic fibers, and an organic binder into water containing a surfactant to form a slurry, and foaming the composition using the surfactant as a foaming agent. The present invention relates to a method for producing a lightweight inorganic material, which comprises molding a lightweight inorganic material into a predetermined shape and drying it, which is characterized in that gum arabic is blended into the foamed slurry used as a cell shape retaining agent. Inorganic materials have excellent advantages such as being non-flammable, extremely stable in terms of alphabet, and many of the materials are relatively inexpensive. However, on the other hand, it has disadvantages such as its high density, which makes the product heavy and difficult to handle, and its high thermal conductivity, making it unsuitable as a heat insulating material. The present invention focuses on the nonflammability of such inorganic materials, takes advantage of this advantage, and overcomes the disadvantages of being heavy and having poor insulation properties by reducing weight by incorporating air bubbles, thereby combining nonflammability, heat insulation, and lightness. The purpose is to provide excellent materials with excellent properties. Conventional lightweight bodies using inorganic powders include those manufactured by mixing air bubbles and lightweight aggregates during hardening of self-hardening inorganic powders such as gypsum and cement, and those manufactured by mixing non-self-hardening inorganic powders with organic/inorganic binders. It is known that the composition is made by mixing air bubbles and lightweight aggregates into the composition. Among these, plaster
Products using self-hardening inorganic powders such as cement can produce high-strength products that can be used as structural members, as seen in lightweight aerated concrete (ALC). is necessary. For this reason, there are problems in that it is difficult to manufacture products with low bulk specific gravity, and that they lack flexibility and are brittle. In addition, even if you ignore strength and try to obtain a product with a low bulk specific gravity, if the specific gravity is below a certain level, the self-hardening properties as a whole tend to be lost, and even if you use inorganic fibers as a reinforcing material, it will be difficult to maintain the shape. Become. Therefore, in order to maintain a low specific gravity, not only an inorganic binder and a foam entraining agent are required, but also a solution to the problem of how to maintain the foam morphology until the final stage. A decomposable foaming agent that uses a surfactant or a chemical reaction to create a slurry whose main ingredients are non-self-hardening inorganic powder and an organic or inorganic binder, water as a medium, and optionally various fibers as a reinforcing agent. The method of mixing air bubbles into slurry and molding using a slurry has the advantage of being easy to handle because it is non-self-hardening. However, the binding effect of the binder does not occur in the presence of a large amount of water, and the effect begins to be exerted when the moisture content decreases near the end of drying, resulting in the collapse of air bubbles during the drying process and deterioration of the surface condition. However, it has problems such as increased bulk density and poor powder dispersion. As mentioned above, the biggest problem in manufacturing a lightweight body using a method that uses inorganic powder, inorganic fiber, and organic binder as the main ingredients and molds it by mixing air bubbles into the slurry using a foaming agent. The key is how to maintain the cell morphology until the end of drying, when the binder takes full effect. The present inventors have conducted intensive research to overcome this problem, and as a result, have arrived at the present invention. The present invention is characterized in that gum arabic is used as a cell shape retaining agent in the production of an inorganic lightweight body that is poured into water to form a slurry and foamed using the surfactant as a foaming agent. In the method of the present invention, in particular, by using gum arabic as a cell shape maintaining agent, it is possible to maintain cells in the drying process, produce products with good surface conditions, low bulk specific gravity as designed, and uniform dispersion of inorganic powders and inorganic fibers. This shows extremely excellent effects such as maintenance of . The gum arabic used in the present invention is a water-soluble polymer. Water-soluble polymers include polyvinyl alcohol, polyvinyl alcohol-based polymers, polyacrylic acid leaders, methylcellulose, sodium alginate, starch, casein, gelatin, and polyethylene oxide, and it is well known that they are used as binders and thickeners. It is being However, none of these water-soluble polymers has the same effect as gum arabic as a cell shape retaining agent, and only gum arabic has an excellent cell shape retaining function. Since gum arabic has a very complex structure, it is not clear why it exhibits the bubble retention effect. The amount of gum arabic blended in the present invention is not particularly limited, but is preferably 0.02 to 0.02 of the total solid content.
It is 5 parts by weight. The reason for this is that when the amount is less than 0.02 parts by weight, the expected effect is not sufficient, and when it is more than 5 parts by weight, the effects of the present invention are fully expressed, but the nonflammability, which is a characteristic of inorganic materials, is likely to be impaired. be. As the inorganic powder referred to in the present invention, various inorganic substances such as calcium carbonate, aluminum hydroxide, gypsum dihydrate, calcined gypsum, gypsum whisker, kaolin, tank, clay cement, and quicklime can be used. It is also possible to use lightweight aggregates such as perlite and shirasu balloons instead of these inorganic powders. The inorganic fibers used in the present invention include rock wool, asbestos,
Examples include mineral cotton and glass fiber. Glass fiber has a particularly strong reinforcing effect, and the fiber is
The 25mm one is better. Glass fibers are usually used in the form of a collection of several hundred single fibers, but it is desirable to defibrate them down to the single fibers in order to increase the reinforcing effect. Furthermore, when the product is flexible, the smaller the fiber diameter, the more preferable it is from the standpoint of imparting flexibility. All of the above-mentioned inorganic fibers have the effect of imparting flexibility to the product, but it is preferable to use rock wool or mineral wool from the viewpoint of economy and non-toxicity. Using rock wool or mineral wool as the inorganic fiber,
When a cationic surfactant is used as the surfactant, the resulting foamed slurry has good fiber dispersion and foaming. When anionic or nonionic surfactants were used, the foaming state was poor, bulky products could not be obtained, and the fiber dispersion state was not very good. The cause of this is not clear, but it is thought to be due to the interaction between the surface charge of rock wool or the like in the water slurry and the charge of the surfactant. Inorganic fibers may be used alone or in combination. Examples of the organic binder used in the present invention include vinyl acetate polymer emulsion, ethylene-
Vinyl acetate polymer emulsion, acrylic polymer emulsion, water-soluble phenol resin, urethane polymer emulsion, water-soluble urethane resin,
Any vinyl chloride polymer emulsion or the like can be used. As the surfactant used in the present invention, any of nonionic, cationic, and anionic surfactants can be used, but cationic surfactants are less affected by the difference in the type of inorganic fiber. This is preferable. Examples of cationic surfactants include alkyltrimethylammonium chloride, dialkyldimethylammonium chloride, alkylaralkylammonium chloride, quaternary ammonium salts containing an amide bond in the alkyl group, alkylamine acetate, polyoxyethylene alkylamine, etc. amines and their salts, and alkyl derivatives of cyclic imines such as pyridine and imidazoline. Among these, quaternary ammonium salts are particularly desirable from the viewpoint of fiber dispersibility and bubble formation. Although any inorganic powder can be used in the present invention, it is preferable that the inorganic powder is a non-hydraulic inorganic powder because it is easy to handle during production and the resulting product is flexible. It is something. In particular, when a mixture of 100 parts by weight of hydraulic inorganic powder and 100 to 600 parts by weight of non-hydraulic inorganic powder is used as the inorganic powder, molding becomes easy without significantly affecting the physical properties, and slurry can be formed in the form of crystallization water. This has the advantage of reducing drying time due to the entrapment of water, while at the same time having the unexpected advantage of increasing the uniformity of the foamed product. When the non-hydraulic inorganic powder is less than 100 parts by weight per 100 parts by weight of the hydraulic inorganic powder, the hydraulic properties become too strong and the product becomes brittle due to the presence of the non-hydraulic inorganic powder, and the surface condition and foaming condition are deteriorated, which is not preferable. do not have. Moreover, if the amount exceeds 600 parts by weight, it becomes difficult to obtain the desired effect, which is not desirable. In addition, in the present invention, thickeners, dispersants, waterproofing agents, plasticizers, crosslinking agents, pigments, etc. may be used in combination without any problem. The present invention will be specifically explained below with reference to Examples. Note that all parts hereinafter refer to parts by weight. Example 1 Ethylene-vinyl acetate copolymer resin emulsion (Dainippon Ink & Chemicals Co., Ltd. trade name: EVDIC EP)
-11) Mix and stir 20 parts of a 5% aqueous solution of a cationic surfactant (Kao Atlas Co., Ltd., trade name Cortamine 24P), 10 parts of a 5% aqueous solution of gum arabic (grade 1 reagent), and 30 parts of water. Next, add 80 parts of calcium carbonate (Shiraishi Calcium Co., Ltd., trade name: Whiten 450) and 10 parts of Rock Wool (Nippon Steel Chemical Co., Ltd., trade name: S-Fiber Granular Cotton), and mix with a hand mixer until the Rock Wool is completely deflated. (Product name National MK-
220A) or a homogenizer at high speed to obtain a foamed slurry with uniform, fine bubbles. Next, the foamed slurry thus obtained was poured into a 220 x 220 x 10 mm mold to shape the surface, and then dried for 60 minutes in a hot air dryer set at 110°C. Table 1 shows the thickness, bulk specific gravity, surface condition, and bubble condition of the obtained molded product. Example 2 20 parts of ethylene-vinyl acetate copolymer resin emulsion (EVADIC EP-11), 15 parts of a 5% aqueous solution of gum arabic (grade 1 reagent), and 30 parts of water were mixed and stirred. Next, add aluminum hydroxide (Showa Light Metal) to this.
Add 60 parts of Yoshino Gypsum Co., Ltd. (trade name: H-10), 20 parts of calcined gypsum (Yoshino Gypsum Co., Ltd., trade name: Yoshino Gypsum Class B), and 10 parts of Lorque Wool (S-Fiver granular cotton), and mix at high speed as in Example 1. A foamed slurry was obtained. 1 part of glass fiber (Nitto Boseki Co., Ltd. trade name: Chip Strand CS13PE-802) was added to this foaming slurry, mixed for a short time, and then poured into a 220 x 220 x 10 mm mold and molded at 110°C for 60 minutes. Drying was carried out for minutes. Table 1 shows the physical property data of the obtained molded product. Comparative Examples 1 to 7 Polyvinyl alcohol with a degree of polymerization of 1750 and a degree of saponification of 98.5% (Kuraray Co., Ltd. trade name Poval 117) 10 parts instead of 10 parts of 5% aqueous gum arabic solution in Example 1
% aqueous solution (Comparative Example 1), 10 parts of a 5% aqueous solution of sodium polyacrylate (1st grade reagent) (Comparative Example 2), methylcellulose with a degree of polymerization of 4000 (trade name Metrose 60SH, manufactured by Shin-Etsu Chemical Co., Ltd.) SH) 10 parts of 2% aqueous solution (Comparative Examples 3 and 4), sodium alginate (Reagent 1)
grade) 10 parts of 5% aqueous solution (Comparative Example 5), starch (Reagent 1)
A molded article was produced in the same manner as in Example 1, except that 10 parts of a 5% aqueous solution of gelatin (grade 1) (Comparative Example 6) and 10 parts of a 5% aqueous solution of gelatin (grade 1 reagent) (Comparative Example 7) were used. Table 1 shows the physical property data of the molded bodies having each of the compositions thus obtained. Comparative Examples 8 and 9 Instead of the cationic surfactant in Example 1, a nonionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd. Neugen ET170) 5*20 parts of aqueous solution (Comparative Example 8), an anionic surfactant ( Daiichi Kogyo Seiyaku Co., Ltd. (Product name: Hitenol 325D) Kao Atlas Co., Ltd. (Product name: D-3-D) 5
A molded article was produced in the same manner as in Example 1, except that 20 parts of the % aqueous solution (Comparative Examples 9 and 10) was used. Table 1 shows the physical property data of the molded bodies having each of the compositions thus obtained.

【table】

[Table] As shown in Table 1, the product produced by the method of the present invention using gum arabic as a cell shape retaining material has a thickness of 10 mm as designed, and is lightweight with a specific gravity of 0.19 to 0.20 g/ ^mm3 . The surface condition is smooth when formed, and the dispersion condition of the cellular inorganic powder is very good. On the other hand, the comparative example product could not maintain the thickness as designed, and the specific gravity was 0.33~
It is getting heavier at 0.4. Furthermore, since neither the surface condition nor the bubble morphology can be maintained, countless holes are formed, resulting in significant unevenness.

Claims (1)

[Scope of Claims] 1. A foamed slurry obtained by adding a composition mainly composed of inorganic powder, inorganic fibers, and an organic binder to water containing a surfactant is shaped into a desired shape. . A method for producing a lightweight inorganic material by heating and drying, the method comprising blending gum arabic as a cell shape retaining agent into the foamed slurry. 2. The method for producing an inorganic lightweight body according to claim 1, wherein the inorganic fibers contain inorganic fibers that are negatively charged in the water slurry, and the surfactant is a cationic surfactant. . 3. The method for producing an inorganic lightweight body according to claim 1, wherein the inorganic powder is a non-hydraulic inorganic powder. 4. The method for producing a lightweight inorganic body according to claim 1, wherein the inorganic powder consists of 100 parts by weight of a hydraulic inorganic powder and 100 to 600 parts by weight of a non-hydraulic inorganic powder.