Compostable and thermoplastic cellulose ether-2-hydroxy-carboxylic acid esters and mixed esters
CA 2204701 A1 · Owner: Wolff Walsrode Ag · Inventors: Dijkstra, Dirk Jacques; Koch, Rainhard; Muller, Hanns Peter
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The present invention relates to thermoplastic water-insoluble and fully compostable, cellulose ether esters which can be described by the general structure (I) (see fig.I), wherein cell-O represents the substituted radical of a hydroxyl group on the cellulose chain and B is a polymeric ether group having the structure (III) wherein E stands for an aliphatic, branched or unbranched chain with 2 to 4 C atoms n is an integer, from 1 to 5 and in the event that n equals 0 at least one of the groups A is a methyl, ethyl, benzyl, carboxyalkyl, sulphoalkyl or cyanoethyl group (see fig.II), and at least one of the groups A is a 2-hydroxycarboxylic acid having the structure (II), -(E-O)n- (III), D1 …
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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Filed May 7, 1997. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended May 7, 2017.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by May 7, 2019.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.