Composite article comprising aerogel particles, ceramic and/or glass fibers and opacifiers
A method for the preparation of a composite article containing aerogel particles, graphite and ceramic and/or glass fibers, as well as to a composite article obtained by this method, are described.
1 . A method for the preparation of a composite article comprising aerogel particles, graphite and ceramic and/or glass fibers, the method comprising:
providing a fibrous article comprising ceramic and/or glass fibers,
providing an aerogel composition comprising an aerogel powder, graphite and an organic solvent,
combining the fibrous article and the aerogel composition, and
partially or completely removing the organic solvent to obtain the composite article.
2 . The method for the preparation of a composite article according to claim 1 , wherein the ceramic fibers contain 80 wt.-% or more of alumina, wherein the ceramic fibers contain less than 2 wt.-% of components other than silica and alumina, based on the total weight of the ceramic fibers.
3 . The method for the preparation of a composite article according to claim 1 , wherein the ceramic fibers contain 2 to less than 80 wt.-% alumina and 10 to 98 wt.-% of silica, based on the total weight of the ceramic fibers.
4 . The method for the preparation of a composite article according to claim 1 , wherein the ceramic fibers contain less than 2 wt.-% alumina, and contain 50 to 85 wt.-% silica and 15 to 50 wt.-% alkaline earth metal oxide.
5 . The method for the preparation of a composite article according to claim 1 , wherein the organic solvent is a hydrocarbon solvent or an alcohol solvent or any mixture thereof.
6 . The method for the preparation of a composite article according to claim 1 , wherein the aerogel is silica aerogel.
7 . The method for the preparation of a composite article according to claim 1 , wherein the aerogel has a porosity of 85% or higher, as determined by isotherm adsorption and desorption.
8 . The method for the preparation of a composite article according to claim 1 , wherein the aerogel has a specific surface area of 300 m 2 /g or higher, as determined by DIN ISO 9277 2003-05 (Determination of the specific surface area of solids by gas adsorption using the BET method).
9 . The method for the preparation of a composite article according to claim 1 , wherein the aerogel composition is a dispersion of the aerogel powder in the organic solvent, and the combined content of aerogel powder and organic solvent in the aerogel composition is 90 wt.-% or more, based on the total weight of the aerogel composition.
10 . The method for the preparation of a composite article according to claim 1 , wherein the fibrous article and the aerogel composition are combined by injecting, or impregnating or soaking the aerogel composition into the fibrous article.
11 . The method for the preparation of a composite article according to claim 1 , wherein the composite article contains 15 to 70 wt.-% aerogel based on the total weight of the composite article.
12 . The method for the preparation of a composite article according to claim 1 , wherein at least 50% of the fibers in the composite article have a length of 10 mm or more.
13 . The method for the preparation of a composite article according to claim 1 , wherein the weight ratio of the one or more aerogels to the one or more fibers in the composite article is 1:4 or higher.