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AssigneeBorregaard ChemCell
InventorsJustin T. Scarpello, Asbjorn E. Bratekas, Ove Bartholsen, Torgeir Hjerde
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The present invention relates to a method for treating a mixture containing cellulose, comprising at least one step of adding at least one agent capable of reducing carbonyl groups. The invention further relates to a specialty cellulose pulp, obtained by a method comprising said treatment. Furthermore, the invention relates to the use of the specialty cellulose pulp according to the invention or the specialty cellulose pulp obtained by a method according to the invention for the production of cellulose derivatives or materials containing cellulose molecules, including but not limited to, cellulose ethers or cellulose esters. Cellulose derivatives obtained from the specialty cellulose pulp according to the invention display increased viscosity and/or improved brightness over cellulose derivatives obtained from specialty cellulose pulp not subjected to the inventive treatment.
A method for treating a mixture containing cellulose that has not been pulped or that has been pulped chemically or chemically and mechanically, characterized in that the treatment comprises at least one step of adding at least one agent capable of reducing carbonyl groups.
A method according to any of the preceding claims, characterized in that the mixture containing cellulose is obtained from (i) chemically or chemically and mechanically pulping wood or is obtained from (ii) unpulped cotton linters or from any combination of (i) and (ii).
A method according to any of the preceding claims, characterized in that the mixture containing cellulose is an aqueous slurry of cellulose leading to a specialty cellulose pulp.
A method according to any of the preceding claims, characterized in that the at least one agent capable of reducing carbonyl groups is selected from the group of borohydrides, DMAB, LiAlH and mixtures thereof.
A method according to any of the preceding claims, characterized in that the overall content of agent capable of reducing carbonyl groups added to the mixture containing cellulose is from 0.1 to 200 g·moles per ton of the dry mixture containing cellulose.
A method according to any of the preceding claims, characterized in that the step of adding at least one agent capable of reducing carbonyl groups is performed at temperatures from ambient temperature to 90° C.
A method according to any of the preceding claims characterized in that the step of adding at least one agent capable of reducing carbonyl groups is performed at a pH value from 8 to 14.
An integrated method for producing specialty cellulose pulp comprising at least the following steps:
Specialty cellulose pulp, obtainable by a process comprising at least one step of treating a mixture containing cellulose that has not been pulped or that has been pulped chemically or chemically and mechanically, characterized in that the treatment comprises at least one step of adding at least one agent capable of reducing carbonyl.
Dependencies are inferred from the claim text.