Process for producing porous alginate-based aerogels

Patent metadata

Field	Value
Publication number	US-2017081494-A1
Application number	US-201515312541-A
Country	US
Kind code	A1
Filing date	May 18, 2015
Priority date	May 19, 2014
Publication date	Mar 23, 2017
Grant date	—

Abstract

The present invention relates to a process for preparing a porous material, at least comprising the steps of providing a mixture (I) comprising a water soluble polysaccharide, at least one compound suitable to react as cross-linker for the polysaccharide or to release a cross-linker for the polysaccharide, and water, and preparing a gel (A) comprising exposing mixture (I) to carbon dioxide at a pressure in the range of from 20 to 100 bar for a time sufficient to form a gel (A), and depressurizing the gel (A). Gel (A) subsequently is exposed to a water miscible solvent (L) to obtain a gel (B), which is dried. The invention further relates to the porous materials which can be obtained in this way and the use of the porous materials as thermal insulation material, for cosmetic applications, for biomedical applications or for pharmaceutical applications.

First claim

1 : A process for preparing a porous material, comprising:
a) providing a mixture (I) comprising
(i) a water soluble polysaccharide,
(ii) a compound suitable to react as cross-linker for the polysaccharide or to release a cross-linker for the polysaccharide, and
(iii) water;
b) preparing a gel (A) by a process comprising
b1) exposing the mixture (I) to carbon dioxide at a pressure in a range of from 20 to 100 bar for a time sufficient to form a gel (A), and
b2) depressurizing the gel (A);
c) exposing the gel (A) to a water miscible solvent (L) to obtain a gel (B); and d) drying of the gel (B).

2 : The process according to claim 1 , wherein the water soluble polysaccharide is selected from the group consisting of agar, alginate, carrageenan, cellulose, hyaluronic acid, pectin, starch, xanthan gum, modified cellulose, chitin, chitosan, and a mixture thereof.

3 : The process according to claim 1 , wherein the water soluble polysaccharide is an alginate.

4 : The process according to claim 1 , wherein the preparing in b) is carried out at a temperature in a range of from 10 to 40° C.

5 : The process according to claim 1 , wherein carbon dioxide in the exposing in b1) is gaseous.

6 : The process according to claim 1 , wherein the compound suitable to react as cross-linker for the polysaccharide or to release a cross-linker for the polysaccharide is selected from the group consisting of a carbonate, a hydroxy carbonate, and a mixture thereof.

7 : The process according to claim 1 , wherein the compound suitable to react as cross-linker for the polysaccharide or to release a cross-linker for the polysaccharide in the mixture (I) comprises calcium carbonate.

8 : The process according to claim 1 , wherein the solvent (L) is selected from the group consisting of an ether, an ester, an alcohol, a ketone, an aldehyde, an alkyl alkanoate, an amide, a sulfoxide, an organic carbonate, an aliphatic and cycloaliphatic halogenated hydrocarbon, a halogenated aromatic compound, a fluorine-containing ether, and a mixture thereof.

9 : The process according to claim 1 , wherein the solvent (L) is selected from the group consisting of a C1 to C6 alcohol, a C1 to C6 ketone, and a mixture thereof.

10 : The process according to claim 1 , wherein a water insoluble solid (S) is added to the mixture (I).

11 : The process according to claim 1 , wherein a compound (C) which is suitable to form a gel is added to the mixture (I) in the providing in a).

12 : The process according to claim 1 , wherein the exposing in c) is carried out at a pressure in a range of from 10 to 100 bar.

13 : The process according to claim 1 , wherein the drying in d) is carried out by converting a liquid in the gel (B) into a gaseous state at a temperature and a pressure below the critical temperature and the critical pressure of the liquid in the gel (B).

14 : The process according to claim 1 , wherein the drying in d) is carried out under supercritical conditions.

15 : A porous material, which is obtained or obtainable by the process according to claim 1 .

16 : A cosmetic, biomedical, or pharmaceutical product, comprising:
a thermal insulation material comprising the porous material according to claim 15 .

17 : A cosmetic, biomedical, or pharmaceutical product, comprising:
a thermal insulation material comprising a porous material obtained or obtainable by the process according to claim 1 .

Assignees

• Basf Se

Inventors

• Fricke Marc
• Weinrich Dirk
• Loelsberg Wibke
• Subrahmanyam Raman
• Smirnova Irina
• Gurikov Pavel

Classifications

• C08J9/35

  Composite foams, i.e. continuous macromolecular foams containing discontinuous cellular particles or fragments · CPC title

• C08J2305/04

  Alginic acid; Derivatives thereof · CPC title

• C08J9/0066 Primary

  Use of inorganic compounding ingredients · CPC title

• C08J9/122

  Hydrogen, oxygen, CO2, nitrogen or noble gases · CPC title

• C08J2205/022

  Hydrogel, i.e. a gel containing an aqueous composition · CPC title