Polysaccharide aldehydes prepared by oxidation method and used as strength additives in papermaking
AssigneeNational Starch and Chemical Investment Holding Corporation
InventorsA. Levent Cimecioglu, John S. Thomaides
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Abstract
Polysaccharide aldehydes are prepared using selective oxidation involving the use of nitroxyl radical mediated aqueous oxidation with a limited amount of oxidant and defined reaction conditions. These polysaccharide aldehyde derivatives having maximum effective aldehyde and minimal carboxylic acid levels making them especially useful as wet, temporary wet and dry strength additives for paper.
Claims18
A method for preparing polysaccharide aldehyde derivatives having maximum effective aldehyde content comprising oxidizing polysaccharide in an aqueous solution with an oxidant having an equivalent oxidizing power of up to 14.18 g of active chlorine per mole of polysaccharide anhydrosugar unit (“ASU”) and an effective mediating amount of nitroxyl radical, the reaction being carried out at a temperature of at or less than about 15° C. and a pH of from about 8.0 to 10.5, the resulting product having up to 15 mole % of C-6 aldehyde groups per mole of polysaccharide ASU and aldehyde to carboxylic acid ratios of greater than or equal to 0.5 based on moles of polysaccharide ASU of each functionality.
Dependencies are inferred from the claim text.