SU1715778A1 - Mixture for producing heat insulating material - Google Patents

Abstract

The invention relates to thermal insulation materials, in particular to thermal insulation boards based on basalt fibers. In order to increase the elasticity of the insulating material -. la mixture contains, wt%: a salt of silicic acid (in terms of silica) 0.5-1.9; ammonium salt (in terms of ammonium ion) 0.08-0.34; basalt ultra, - superfine fiber - the rest, with a ratio of NH%: Si02 (0.15-0.18) 1. With a product density of 90-116 kg of 1 m, the coefficient of thermal conductivity at 25 ° C is 0.028-0.031 W / µ, the tensile strength at stretching is 0.19-0.20 MPa, and the flexibility is 50 mm. 2 tab.

Description

The invention relates to heat insulating materials, in particular to heat insulating cardboard based on basalt fibers.

The aim of the invention is to increase the elasticity of the insulating material.

The essence of the invention lies in the fact that the following NH4 +: Si02 ratio was found (due to an increase in the ammonium salt content), which leads to the gelding of the binder at a temperature of 60-70 ° C and at the same time is stable during circulation and long-term storage in various containers (which is achieved by changing the technology of binder preparation).

The mixture for the manufacture of the heat insulating material and the material itself are made as follows.

Ultra-thin or super-thin basalt fiber canvas or a mixture of these fibers, 0.6–3.0 µm in diameter, is continuously fed to a conveyor moving at a speed of 0.5–0.6 m / min. A binder is applied to the canvas by the method of irrigation, distributed as a flat jet across the entire width of the conveyor. The moistened canvas passes under the squeeze rolls and above the vacuum box, sucking off excess binder. This circulating binder enters the collecting tank, from where it is continuously pumped into the mixing tank, where it is diluted with stirring the previously measured volume of concentrated silica sol.

For these purposes, silica sol is used according to TU 48-1919-02-86 with a silica concentration of 3.5-4.5 wt.%, Sodium oxide 0.03 wt.%, With a pH of pH of 8.2- 10.0 and a density of 1.01-1.02 g / cm. The supply of the circulating binder is stopped when the volume of solution in the blender tank reaches the calculated value. In the prepared solution, the content of ingredients, expressed as c

ate VJ -h

00

The OTHOLueHMe NH + 4: Si02 cut is such that it provides a long-lasting (at least 8 h) steady state of silica sol. At the same time, an aqueous solution of an ammonium salt (chloride, sulphate or ammonium nitrate) is prepared in the second mixing tank.

After the previously prepared identical solutions are used up, the first and second mixer tanks are connected to the distributor mixer and the first and second solutions are fed at a rate that provides the binding ratio NH + i: Si02- 0 at the outlet of the mixer-distributor 15--0.18): 1; Binder contains ingredients, wt%: Sol of silicic acid (in terms of S102) 0.56-1, -94

Ammonium salt (in terms of) 0.08-0.35 Water Else The binder is added to s scrim, resulting in a mixture to make a heat insulating material with the following component content, wt%: Sol of silicic acid (in terms of SI02 ) 0.5-1.9 Ammonium salt (Q in terms of MH%) 0.08-0.34 Basalt fiber Remaining Moistened canvas enters the conveyor dryer where it is subjected to heat treatment at 180-250 ° C.

At the first stages of heat treatment at a mixture temperature, the binder with the ratio NH%: SI02 (0.15-0.18): 1 gels. Since gelation occurs at a temperature lower than the temperature of water vaporization on the surface of the material, the colloidal particles in the mixture do not migrate from the inner regions of the material to the peripheral ones together with the diffusing moisture. As a result, the homogeneity of the bulk structure of the material is improved, which improves the quality of the material. Thermal insulating cardboard comes out of the dryer in a continuous stream, which is cut at the exit into sheets of required size.

Examples of the compositions of the proposed mixture are given in Table 1, and the properties of the heat insulating material made from it are given in Table 2.

The coefficient of thermal conductivity when the material is heated increases with increasing temperature, the averaged values of the coefficient (W / µm) at various temperatures are as follows:

A (25 ° C) 0.029; A (155 ° C) 0.052;

A (300 ° C) 0.103; I (700 ° C) 0.273. Thermal insulation material from the proposed mixture has a high uniformity of bulk structure; its surface is devoid of compacted crust, which is characterized by increased brittleness and thermal conductivity. As follows from Examples 1-5 of Table 2, the result is an increase in elasticity, characterized by a reduction of the test cylinder diameter to 5 mm, which the material covers when bent without breaking. Other technical characteristics of the heat insulating material, including humidity, which is 1.25-1.36%. The return rate, which is 98.2-98.6%, is almost the same in magnitude as a known material.

Claims (1)

The use of the invention will make it possible to reduce energy losses in thermal units, in the thermal insulation of which the material from the proposed composition will be used, and the field of application of the material will also be expanded. Claims of the Invention A mixture for the manufacture of a heat insulating material, including silica sol, ammonium salt and basalt ultra-thin fibers, which, in order to increase the elasticity of the heat insulating material, it contains ammonium salt and silica sol with respect to them. mass fractions (in terms of ammonium ion and silicon dioxide) (0.15-0.18): 1 in the following ratio of components. wt.%: Sol of silicic acid (in terms of Si02) 0, 9 Ammonium salt (in terms of MNC) 0.08-0.34 Basalt ultra-hyperfine fiber Remaining Seeming density KG / M 3 Heat conductivity coefficient, W / (m.K) at Strength at stretching, MPa Flexibility mm 90 112 90  116 89-117 .0,031 0,028 0,029 0,028 0,031 0,029-0,033 0.20 0.22 0.20 0.21 0.19 0.1-0.2. 50 50 50 50 50 217