SU1278218A1 - Method of manufacturing heat-insulating articles - Google Patents

Abstract

In order to increase strength and reduce the density and thermal conductivity of products, heat treatment of them is carried out stepwise: in the first stage at 300-380 ° C for 12-25 minutes, and in the second stage - at 200 ° C for min. . 1 tab.

Description

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with:

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The invention relates to the field of building materials, in particular to the production of heat insulating products.

The purpose of the invention is to increase the strength and reduce the density and thermal conductivity of products.

During the drying process, the exothermic curing reaction of the lignin becomes controlled by the use of a stepwise heat treatment.

Before carrying out an exothermic reaction, the products are dried at a temperature below the temperature of the occurrence of an exothermic reaction (190-210 ° C), to a residual moisture content of 3-5 May / a.Hold the dried products at 300-350 ° C for 12-25 minutes, they are heated to and to a depth sufficient l, l the occurrence of an exothermic reaction and its distribution but the entire volume of products.

At the second stage of heat treatment of products at 110–200 ° C for 20–35 min, an exothermic reaction rate is established at which the temperature in the product is kept constant. This is achieved due to the equilibrium between the heat removal rates from the product and the heat input into the product from the exothermic lignin condensation reaction. The rate of exothermic reaction depends on the temperature difference between the inside of the product and the space surrounding the product. With the increase of this difference, the speed increases. Therefore, holding at a temperature below 110 ° C increases the reaction rate so much that excess heat does not have time to be removed from the product and the binder burns out. Exposure at temperatures above 200 ° C makes heat exchange between the product and its surroundings difficult 18 18 18 12 25 15

Preferred

so much that the heat from the lignin condensation reaction also accumulates in the product, the binder burns out. Exposure of products in this temperature range for 20-35 minutes is necessary and sufficient for complete curing of lignin.

Example. Perlite sand is mixed with an aqueous solution of sulphite lignin –RDB in a forced-action mortar for 5 minutes. Then, from the obtained mixture with a moisture content of 30 wt.%, The samples are molded with a size of 100% SO50 X50 mm by pressing and subjected to drying and stepwise heat treatment. The content of dry SB in the samples is 30 wt. ° / o, the density of the samples is 175 kg / m.

Stirring the aqueous solution of the MDB with mineral wool is carried out in a propeller mixer. First, the pulp is prepared, then it is poured onto the net and vacuumized. After that, the moisture content of the sample is 60 wt.% / O, the content of dry DBP is 30 May / o, and the density of the samples is 175 kg / M.

The finished samples are placed in a drying oven and subjected to drying and stepwise heat treatment.

The compressive strength of the samples of expanded perlite is determined according to GOST 17177-71. The compressibility of mineral wool samples is determined according to GOST 17177–171 under a specific load of 0.02 kgf / cm. The moisture resistance of the samples from expanded perlite is estimated by the ratio of compressive strength of samples kept in an environment of saturated water vapor for 72 hours to the strength of dry samples. Moisture - Bone samples of mineral wool are evaluated by the relative change in compressibility according to GOST 9573-72.

The test results are shown in the table.

0.27 (4)

20 20 20 20 20 20

0.29 (4)

0.29 (4)

0.29 (4)

0.23 (4)

0.27 (6)

7350 15 200 20

8350 15 180 35 Known for 9 220-260

The table shows that the heat insulating material based on perlite has the maximum compressive strength, and the material based on mineral wool - the minimum compressibility and the minimum relative change in the compressibility value during heat treatment.

Thus, the proposed method makes it possible to obtain waterproof materials of a density of 175 kg / m, compressive strength of 0.28 MPa from a granular or fibrous inorganic material binding a water-soluble lignin. Compared with the known method, this allows reducing the material consumption of products by two times, significantly increasing their efficiency due to the low thermal conductivity of 0.046 W (M-K), compared to 0.072 W / (MK) for products with a density of

Table continuation

0.28 (4) 0.28 (4)

0.5 (at a density of 250 kg / mz)

O (at a density of 175 kg / mz)

250 kg / m, obtained by the known method of the 25 ° formula of the invention

A method of manufacturing heat insulating products from a granular or fibrous material, preferably perlite or mineral wool, in a binder of water-soluble lignin, by mixing the components of the raw mix, molding, drying, and heat-treating products, characterized in that and thermal conductivity of products, heat treatment is carried out stepwise: at the first stage at 300-380 ° C for 12-25 minutes, and at the second - at 110-200 ° C for 20-35 minutes.

Claims (1)

Claim A method of manufacturing heat-insulating products from granular or fibrous material, mainly perlite or mineral wool, on a binder from water-soluble lignin, by mixing the components of the raw material mixture, molding, drying and heat treatment of products, characterized in that, in order to increase strength and reduce density and heat conductivity of products, heat treatment is carried out stepwise: at the first stage at 300-380 ° C for 12-25 minutes, and at the second stage ₄ θ swarm - at 110-200 ° C for 20-35 minutes. Compiled by N. Koshelev Editor S. Patrusheva Order 6798/16 Tehred I. Veres Corrector S. Czerny Circulation 555 Subscription VNIIIPI of the USSR State Committee for Inventions and Discoveries 113035, Moscow, Zh-35, Raushskaya nab., D. 4/5 Branch of the PPP Patent, Uzhgorod, ul. Project, 4