Super-critical drying method for fiber needled felt/silicon-aluminum aerogel composite insulation board

Abstract

The invention provides a super-critical drying method for a fiber needled felt / silicon-aluminum aerogel composite insulation board. The super-critical drying method comprises the following steps: performing solvent substitution and hydrophobic modification on fiber needled felt / silicon-aluminum wet gel; placing the wet gel subjected to the hydrophobic modification in a high pressure reactor; pouring a super-critical medium into the reactor; setting a heating temperature for heating; deflating or reflowing after the medium state of the reactor reaches a super-critical state to carry a solvent out of the wet gel till the solvent is recovered fully, wherein the super-critical medium is an acetonitrile, ethanol or carbon dioxide solvent. A product produced with the super-critical drying method provided by the invention has high product yield, high production efficiency and low powder falling rate, and can be amplified industrially; the super-critical drying method can be integrated into a production line; a whole preparation method is easy to operate, is free from strong acid and strong alkali corrosion, has low equipment requirement, and is suitable for industrial production after amplification.

Description

technical field [0001] The invention relates to a drying method for a thermal insulation board, in particular to a supercritical drying method for a fiber needle-punched felt / silicon-alumina aerogel composite thermal insulation board. Background technique [0002] Aerogel is the material with the lowest thermal conductivity among solid substances, which is only slightly higher than vacuum, about 0.013W / m·K. Aerogel also has a very low density, which is recognized as the smallest density solid in the world. The lowest density can be 3kg / m3, which is slightly higher than the density of air. Therefore, aerogel is the thermal insulation material with the best thermal insulation effect and the smallest density in the world. [0003] At present, there are many types of aerogels, including carbon aerogels, silicon-based aerogels, and alumina aerogels. The raw material for the preparation of silica aerogel can be tetraethyl orthosilicate or water glass, and the preparation process...

AI Technical Summary

Problems solved by technology

Therefore, the production cost of raw materials for the traditional preparation of alumina airgel is expensive, and the gel process is complicated; if tetraethyl silicate is used for the preparation of traditional alumina airgel, the gel sol process also needs to undergo hydrolysis and polycondensation of raw materials. The preparation process is more complicated