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Verfahren zur Herstellung von Superabsorbern und mittels eines solchen Verfahrens hergestellte Superabsorber

Production of superabsorber, useful for hygiene article, uses supercritical carbon dioxide in swelling and impregnation and fresh supercritical carbon dioxide during graft polymerization of acrylic acid and/or derivative(s) to cellulose.
 
: Muth, O.; Hirth, T.

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Frontpage ()

DE 1999-19905947 A: 19990212
DE 1999-19905947 A: 19990212
DE 19905947 A1: 20000817
B01J0020
German
Patent, Electronic Publication
Fraunhofer ICT ()

Abstract
Es wird ein Verfahren zur Herstellung von Superabsorbern durch Pfropfcopolymerisation von Cellulose und Acrylsaeure und/oder deren Derivaten vorgeschlagen, wobei die Cellulose in ueberkritischem Kohlendioxid in Gegenwart der Acrylsaeure und/oder deren Derivate sowie eines hierbei im wesentlichen inaktiven Initiators zum Quellen gebracht und impraegniert wird, das mit Acrylsaeure und/oder deren Derivaten beaufschlagte ueberkritische Kohlendioxid entfernt und die gequollene und impraegnierte Cellulose mit frischem ueberkritischen Kohlendioxid beaufschlagt wird und anschliessend Temperatur und/oder Druck derart

 

DE 19905947 A UPAB: 20001023 NOVELTY - Production of superabsorber comprises using a supercritical carbon dioxide in swelling and impregnation and fresh supercritical carbon dioxide during graft polymerization of acrylic acid and/or derivative(s) to cellulose. DETAILED DESCRIPTION - Superabsorber production comprises: (a) swelling cellulose (I) in supercritical carbon dioxide (II) in the presence of acrylic acid and/or its derivative(s) (III) and an initiator (IV) inactive under swelling conditions and impregnating (I) with (III) and (IV); (b) replacing (II) containing (III) with fresh (II); and (c) adjusting the temperature or pressure to activate (IV) and form the graft copolymer by grafting (III) side chains that crosslink (I). An INDEPENDENT CLAIM is also included for superabsorbers produced by this process. USE - The superabsorbers are used for hygiene articles, e.g. diapers, inlays, etc. (all claimed). ADVANTAGE - The process is environmentally friendly, simple and cost effective and makes it unnecessary to use liquid, highly toxic or flammable solvent. Removing supercritical carbon dioxide (II) containing dissolved acrylic acid and/or its derivatives before graft polymerization prevents polymerization to a matrix of e.g. polyacrylic acid containing cellulose. During graft polymerization, (II) increases the mobility of the monomers in the swollen cellulose and hence ensures sufficient polymerization.

: http://publica.fraunhofer.de/documents/PX-63614.html