Preparation method of silicon dioxide-diboron trioxide low-melting-point glass combined hollow glass bead heat-insulating material

Abstract

The invention relates to a preparation method of silicon dioxide-diboron trioxide (SiO2-B2O3) low-melting-point glass combined hollow glass bead heat-insulating material. The method comprises the following steps: using TEOS ( tetraethoxysilane ) as precursor of SiO2 and ethanol as solvent, adding deionized water to promote the hydrolysis of the TEOS and dissolving boric acid serving as the precursor of the B2O3 in ethanol; uniformly mixing the above two solutions according to a mole ratio of B2O3 to SiO2 being (0.56-1.68): 1 and stirring; sealing and standing at room temperature for 48 hours to obtain required sol solution; stirring, then putting in a grinding tool, and pressing into a green body; gelling, drying and sintering to prepare heat-insulating material formed in which beads are directly combined. The hollow material beads are used as main material to prepare the heat-insulating material which is a lightweight high-strength structure material in which beads are directly combined. The apparent porosity reaches 30-60%, the volume density is 0.30-0.50g / cm<3>, and the highest compressive strength can reach 14MPa.

Description

technical field [0001] The invention relates to a thermal insulation material, in particular to a light-weight, high-strength and flame-retardant thermal insulation material; it is silicon dioxide-boron trioxide (SiO 2 -B 2 o 3 ) A method for preparing a low-melting point glass-bonded hollow glass microsphere insulation material. Background technique [0002] At present, the raw materials of lightweight thermal insulation materials mainly include expanded vermiculite, expanded perlite, floating beads, alumina hollow spheres, and hollow glass microspheres. Among these materials, expanded vermiculite and expanded perlite have the same density and thermal conductivity. Lower, but its water resistance is poor. The thermal conductivity of floating beads and alumina hollow balls is very low, and their strength is relatively high, but their density is relatively high. Hollow glass microspheres with a particle size of 2-120 microns and a wall thickness of 1-2 microns. Bulk dens...

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Problems solved by technology

[0003] However, the domestic research on the preparation of hollow microspheres for insulating materials is mainly to fill hollow glass microspheres in organic matrix materials such as epoxy resin or polyurethane. Although the density of this microbead-filled resin composite material is reduced, the mechanical properties are improved. , but since the maximum service temperature of organic materials such as resins does not exceed 300°C, this composite material can only be used for applications under low temperature conditions

The use of floating beads to prepare high-temperature insulation materials, although the strength is relatively large, but the density is relatively large

In foreign countries, the surface of hollow glass microspheres is softened at high temperature to produce a liquid phase, and the microspheres are bonded to obtain a thermal insulation material that directly combines microbeads with microbeads. This material is sintered at a higher temperature, resulting in the loss of the microbeads themselves. The strength decreases, and the strength of the obtained product is defective

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