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US 8,197,699 B2Granted
Process for preparing methylhydroxyalkylcellulose having a small number of coloured particles
AssigneeDow Global Technologies LLC
InventorsMartin Kowollik, Wolfgang Dannhorn, Erik-Andreas Klohr, Hartwig Schlesiger, Bernhard Kranz, Helmut Holste, Gerd Sonnenberg
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Abstract
The present invention describes a process for preparing methylhydroxyalkylcellulose having a small number of colored particles by separation of methylhydroxyalkylcellulose from aqueous suspension with subsequent washing of the methylhydroxyalkylcellulose using a specially equipped rotary pressure filter.
Claims6
A process for preparing methyl hydroxyalkylcellulose comprising the steps of:
- providing a rotary pressure filter including at least one drying zone, said filter comprising:
- at least one heat-resistant, abrasion-resistant plastic separation plate sealing the drying zone(s), said separation plate being made of polyether ether ketone;
- and
- at least one additional separation plate which seals off zones other than the drying zone(s) is made of polyvinylidene fluoride;
- introducing an aqueous suspension containing methylhydroxyalkylcellulose into said rotary pressure filter;
- and
- separating said methylhydroxyalkylcellulose from said aqueous suspension using said rotary pressure filter to obtain a concentrated methylhydroxyalkylcellulose stream.
4 more elements
Dependencies are inferred from the claim text.