JPH0375511B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a composition for producing a foam, and is particularly characterized in that it provides a cement foam with excellent mechanical strength that can be stably foamed and hardened at room temperature. Previously, the present inventors have used soluble alkali silicate as main components, hardening components such as cement and zinc oxide, and a specific foaming stabilizer, and foamed and hardened this through a metal foaming agent. At least we have obtained an inorganic foam. This foam manufacturing technology has not only made it possible to use foam-in-place materials in various applications such as construction and furnace construction, where it was difficult to use conventional materials, but also because of the uniqueness of their components and structure. Therefore, it is also applied to various industrial applications. However, since it uses soluble alkali silicate as an essential component, it is subject to various limitations in use, and problems remain, for example, in adjusting the timing of foaming and curing at low temperatures. In view of these circumstances, the present inventors have continued to investigate, among the constituent components of the above-mentioned foam, especially the functions imparted by each compounded component during the production of the foam. In particular, as a result of continuing research focusing on the components of soluble alkali silicate, it was surprisingly identified that an experiment was carried out to produce foam by dividing it into alkali metal hydroxide and high-silicate powder. It was found that a good foam could be obtained only when the blending ratio was adjusted to , and the present invention was thus completed. That is, the present invention
(a) Mixed cement of calcareous silicate cement and calcareous aluminate cement (hereinafter referred to as (a) component), (b) alkali metal hydroxide (hereinafter referred to as (b) component), (c) high silicate powder (hereinafter referred to as (c) component), and (d) metallic foaming agent (hereinafter referred to as (d) component) as the main components,
A foam is produced by adding water to the mixture and making it into a paste. Each component will be explained in detail below. As mentioned above, component (a) is a mixed cement of silicate calcareous cement and aluminate calcareous cement.
Silicate cement refers to single or mixed hydraulic cements such as ordinary Portland cement, early strength Portland cement, moderate heat Portland cement, silica cement, high sulfate slag cement, fire ash cement, and lime slag cement. This calcareous silicate cement is blended with a calcareous aluminate cement, that is, alumina cement. However, when alumina cement is used alone or in too large a quantity, the curing reaction takes place and the desired foam cannot be obtained.
The amount shall be within 300 parts by weight. Next, component (b) is
It refers to an alkali metal hydroxide such as LiOH, NaOH, and KOH, and when producing foam, it may be in the form of powder, flakes, or an aqueous solution. (c) the component contains at least 70% in its constituent parts;
Highly silicic acid powder containing % by weight of _SiO2 ,
Examples include natural minerals such as silica earth, silica stone, silica sand, and silica flowers, silica dust by-produced during the production of silicon alloys by electric heating or metallurgy, and chemical products such as silica gel and white carbon. These are used in powder form. Component (d) includes those that generate bubbles in an alkaline aqueous solution, such as simple metals, alloys, and intermetallic compounds. The present invention uses the above components (a) to (d) as essential components, and by blending them with water, an inorganic foam can be produced, and the blending ratio is 100 parts by weight of component (a). Component (b) should be about 2 to 150 parts by weight, component (c) should be about 5 to 250 parts by weight, and component (d) should be about 0.1 to 10 parts by weight, especially the (b) and (c) components. is the expression
It is important that the molar ratio expressed by SiO ₂ /R ₂ O (where R is an alkali metal) is within the range of 1.0 to 5.0; if the molar ratio is outside the range, it will be difficult to obtain a desired foam. . The total amount of components (b) and (c) is about 7 to 350 parts by weight per 100 parts by weight of component (a). When blending the above components (a) to (d) to obtain a foam, a mixed powder consisting of components (a), (c), and (d) is prepared in advance, and this mixed powder and The easiest method is to mix and stir an aqueous solution of component (b) to form a paste. Of course, it is also possible to mix a solution system of components (b) + (c) with a powder system of components (a) + (d), and by such a preparation method, the reaction properties of the composition of the present invention and the foam can be changed. It does not particularly impede performance. Once the composition has been prepared into a paste, it gradually starts foaming and undergoes a curing reaction to form a foam. A lightweight, hard foam is produced within 24 hours at the latest from the start of foaming, and this foam has excellent thermal insulation properties. What is noteworthy is that the foaming and curing reaction of this composition proceeds relatively smoothly at extremely low temperatures, and in this respect its properties are different from those of conventional compositions for producing foams. . The composition of the present invention has the above-mentioned properties.
It consists of components (a) to (d), but a so-called foaming stabilizer can be added for the purpose of improving mechanical strength, heat insulation, etc. Effective foaming stabilizers include zeolite, carbon black, etc. , porous inorganic powders such as activated carbon, mineral powders having a layered structure such as mica, talc, sepiolite, and palygorskite, and surfactants that can be used in extremely small amounts. On the other hand, in addition to the above-mentioned essential components, the composition of the present invention also contains inorganic fibers, lightweight aggregates, water-soluble polymers, aqueous dispersions of synthetic polymers, zinc oxide, phosphates, etc. as fillers or strength-improving materials. It can be used as long as it does not interfere with the foam curing reaction of the invention. The present invention will be explained in detail below with reference to Examples. Example 1 80 g of ordinary Portland cement, 20 g of alumina cement, 50 g of silica dust, and 5 g of metal aluminum powder were collected in a polyethylene container and mixed well. On the other hand, a potassium hydroxide aqueous solution obtained by dissolving 25 g of potassium hydroxide in 75 g of water is mixed into the above mixed powder and mixed with thorough stirring. Do this quickly 5
Place in a constant temperature incubator at ℃ and observe from the outside. The mixture started foaming after 40 minutes, and curing was completed after 4.5 hours to obtain a foam. This foam had a bulk specific gravity of 0.27 and a compressive strength of 4.9 Kg/cm ² . Example 2 A foam was obtained in the same manner as in Example 1, except that each component was formulated as shown in Table 1 and water was added as appropriate. When these foams were subjected to the same tests as in Example 1, the results shown in Table 1 were obtained. Comparative Examples 1 to 2 A foam was obtained in the same manner as in Example 1, except that each component was formulated as shown in Table 1 and water was added as appropriate. When these foams were subjected to the same tests as in Example 1, the results shown in Table 1 were obtained. 【table】

Claims (1)

[Scope of Claims] 1 (a) 100 parts by weight of mixed cement of calcareous silicate cement and calcareous aluminate cement, (b) 2 to 150 parts by weight of alkali metal hydroxide, (c) high silica powder (d) 0.1 to 10 parts by weight of a metal blowing agent and water. 2. The composition for producing a foam according to claim 1, wherein the ratio of calcareous silicate cement and calcareous aluminate cement in the mixed cement is 1:3 or less. 3 The amount of silicic acid in the high silicic acid powder is 1.0 to 5.0 per mole of alkali metal oxide in the alkali metal hydroxide.
The composition for producing a foam according to claim 1, which is blended in a molar adjusted manner. 4. The composition for producing a foam according to claim 1, further comprising a foam stabilizer.