Patent EP0178292B1 successfully refreshed from Google Patents.
EP0178292B1
Expired / Lapsed
EP
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Process for preparing cellulose carbamates
Assignee: Lenzing AG
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Filing: 1985-10-07
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Granted: 1989-06-14
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Expires: 2005-10-07
Abstract
No abstract record available.
Inventors
- 👤 Herbert Dr. Griesser
- 👤 Thomas Dipl. Chem. Ing. Jeszenszky
- 👤 Klaus Dr. Weinrotter
- 👤 Raimund Jurkowitsch
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 13:50
CPC Classifications
C; C08; C08B; C08B3/00; C08B3/14; C08B15/00; C08B15/05; C08B15/06
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
63 words
A method of producing cellulose carbamates by impregnating cellulose-containing material with an aqueous solution containing alkali metal hydroxide and urea, heating the impregnated cellulose-containing material to form the cellulose carbamates as well as separating non reacted urea and by-products, characterised in that the material impregnated with alkali metal hydroxide and urea is washed with urea-containing water one or several times prior to heating.
Claim 2
Independent Claim
63 words
A method of producing cellulose carbamates by impregnating cellulose-containing material with an aqueous solution containing alkali metal hydroxide and urea, heating the impregnated cellulose-containing material to form the cellulose carbamates as well as separating non reacted urea and by-products, characterised in that the material impregnated with alkali metal hydroxide and urea is washed with urea-containing water one or several times prior to heating.
Claim 3
Dependent Claim
25 words
A method according to claim 1, characterised in that an aqueous urea solution containing 10 to 25% by mass or urea is used for washing.
Claim 4
Independent Claim
48 words
A method according to one or both of claims 1 and 2, characterised in that a solution containing more than 10 and up to 30% by mass, preferably 11 to 12% by mass, of alkali metal hydroxide, in particular sodium hydroxide, is used for impregnating the cellulose-containing material.
Claim 5
Independent Claim
47 words
A method according to at least one of claims 1 to 3, characterised in that washing of the impregnated material is effected to a content of alkali metal hydroxide of 2% by mass at most, preferably 0.5% by mass at most, based on the dried impregnated material.
References Cited (Backward Citations)
No citation records indexed.
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