Thermal insulating material based on pigment containing silica aerogels

US5122291A · kind A · utility

Assignee

• BASF SE

Inventors

• Bernardo Wolff · Mannheim, DE
• Manfred Mielke · Heidelberg, DE
• Guenther Seybold · Schifferstadt, DE
• Werner Ostertag · Havelsee, DE
• Jochen Fricke · Würzburg, DE
• Roland Caps · Kleinwallstadt, DE

Key dates

• Filing date: May 4, 1990
• Grant date: Jun 16, 1992
• Expiry date: May 4, 2010

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F16L59/08
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

A thermal insulating material based on a pigment-containing silica aerogel is obtainable by PA0 a) reacting an aqueous dispersion of sodium silicate and a pigment with a strong acid or sodium silicate with a pigment-containing strong acid to give a pigment-containing silica hydrogen, the pigment being such that it scatters, absorbs or reflects infrared radiation of wavelength 3-10 .mu.m, PA0 b) substantially freeing the resulting pigment-containing silica hydrogel from ionic constituents by washing with water, PA0 c) displacing the water in the hydrogen by a low-boiling liquid which is inert toward the pigment-containing silica gel, PA0 d) heating the liquid-containing silica gel thus obtained under supercritical conditions while completely covered with the liquid, and PA0 e) subsequently removing the liquid from the solid by flash vaporization at supercritical temperature.