JPS60155583A - Manufacture of lightweight refractory heat insulator - 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 a lightweight fire-resistant heat insulating material mainly made of alumina cement, and aims to provide a method for producing a light-weight and highly fire-resistant heat insulating material in a short time.

Conventionally, it is well known that when gypsum is added to alumina cement, it has the property of accelerating setting under conditions where the curing temperature is around 30°C.

The present invention was completed by researching the properties of a mixture of alumina cement and gypsum from the viewpoint of temperature conditions. 7 to 10 parts by weight of gypsum and water are mixed with 100 parts by weight of alumina cement. The resulting slurry is cast into a mold, then heated at a temperature of to °C or higher, and then demolded,
It is characterized by a step of curing at room temperature and then drying.

As the plaster in the present invention, trihydrate gypsum is most suitable from the viewpoint of setting time, but hemihydrate gypsum and anhydrite gypsum are not suitable because their setting time is too short and workability is difficult.

In addition, the amount of gypsum added is in the range of -10 parts by weight per 100 parts by weight of alumina cement, preferably between 7 parts by weight, and if it is less than 7 parts by weight, the effect of accelerating setting will not be exhibited. Moreover, if it exceeds 10 parts by weight, it is not preferable because it lowers the heat resistance and strength of the final product.

In the present invention, the effect that a light-weight and fire-resistant heat insulating material can be obtained in a short time by the above-mentioned structure is not clear, but it is presumed as follows.

That is, when a raw material slurry consisting of alumina cement and gypsum is heated at a temperature of t0 to /θOb, it first forms so-called bulky ettringite (30aO・AJx Ol ”
30aSO4' @ 32 H2O) is generated to form the skeleton of the formed body, and condensation proceeds at the same time, so the weight of the final formed body is reduced by shaping the ettringite while maintaining its bulkiness. As a result, it is thought that the heat insulation properties will also be improved.

Furthermore, the reason why the heating temperature is set at 40°C or above, especially in the range of 40 to 100°C, is that at temperatures below Ao°C, ettringite is not sufficiently formed and condensation progresses, making it impossible to achieve weight reduction. Calcium monosulfoaluminate hydrate (3CaO・A120s-CaS04・
12H20) is produced in large quantities and inhibits the production of ettringite, resulting in a decrease in strength.

In addition, in the present invention, a thickener, a foaming agent, reinforcing fibers, etc. can be added as necessary.

As a thickener, use methyl cellulose, polyethylene glycol, etc. at 1 part by weight per 100 parts by weight of alumina cement.
It can be added up to about parts by weight, and is effective in preventing separation of raw material slurry, improving water retention, etc.

Further, as foaming agents, surfactants, synthetic resins, etc. can be added up to about 1 part by weight per 100 parts by weight of alumina cement, and are effective in reducing the weight of the molded product.

Furthermore, both organic and inorganic reinforcing fibers can be used, and up to about 2 parts by weight can be added to 700 parts by weight of alumina cement, but from the viewpoint of dispersibility, short fibers are more preferable, and polypropylene Fibers can be suitably used.

The effects of the present invention will be explained below with reference to Examples.

Examples 1-3. Comparative Examples 1 and 2 Alumina cement) 100 parts by weight of gypsum trihydrate,
Polypropylene fibers, methylcellulose, and a surfactant are blended with water in the proportions shown in Table 1, and the mixture is stirred and mixed uniformly to form a raw material slurry.Then, the raw material slurry is divided into dimensions iro x isom and thickness g. After pouring into a cod mold, the mold was heated in a dryer at 20°C for 5 minutes, and then removed from the dryer and demolded.
After curing for a certain period of time in a constant temperature and humidity chamber at 20° C. under a humidity OS condition, the molded product was dried at 101° C. to obtain a molded body.

The physical properties of the molded product are shown in Table 1.

All procedures were carried out in the same manner as in Example, except that the amount of trihydrate gypsum added was 13 parts by weight, and the heating temperature of the molded body and raw material slurry was 30°C. The physical properties of the obtained molded bodies are also listed in Table 1 as Comparative Example 1 and λ, respectively.

Table 1 As is clear from the above examples, the lightweight fireproof insulation material according to the present invention is made by using a raw material slurry containing specific raw materials in specific amounts.
By heating at a temperature of 0° C. or higher, it is possible to condense in a short time and easily obtain a lightweight heat insulating material with excellent heat resistance and strength.

Claims (1)

[Claims] 1. Alumina cement) 7 to 70 per 100 parts by weight
Production of a lightweight fireproof insulation material characterized by the process of casting a slurry of a mixture of parts by weight of gypsum and water, then heating it at a temperature of 0°C or higher, removing the mold, and curing it at room temperature and then drying it. Method.