C - Chemistry – Metallurgy – 08 – B
Patent
C - Chemistry, Metallurgy
08
B
260/217, 260/221
C08B 11/02 (2006.01) C08B 11/00 (2006.01) C08B 11/20 (2006.01) C08B 15/10 (2006.01) C08B 31/00 (2006.01) C08B 31/08 (2006.01) C08B 31/10 (2006.01)
Patent
CA 1061782
A B S T R A C T Ethers of polysaccharides, especially cellulose ehters, are prepared by reacting an alkali metal poly- saccharide (modium starch, sodium cellulose, potassium starch or potassium cellulose) with one or more of a C1-C4 alkyl monochloride, a C2-C4 vicinal epoxide and a C2-C4 monochloride acid or its alkali metal salt, in the presence of an organic diluent at 50°-155°C. The reaction mixture is them neutralized with excess alkali, and the wate and most of the volatile hydroxyl-containing by-products are removed by azeotripic distillation. The etherified polysaccharide is them crosslinked with an unsubstituted mono- or dialdehyde, and the crosslinked product is washed with water at 0°-30°C. The present process has the following advantages over the prior art: 1. Improved heat transfer and thus good control of the reaction temperature are obtained during the etherifi- cation step; 2. There is more uniform contact of the cross- linking agent with the etherified polysaccharide; 3. The product retains substantially its original size and form, which facilitates purification and salt removal; 4. The washed product, because of its uniform, finely divided particle size, dissolves faster in aqueous alkaline media; 5. Neither the polysaccharide nor its ether derivative is in a greatly swollen state nor in a dissolved state during the process; and 6. Azeotroping removes water and some by-products which interfere with crosslinking (i.e., alkanola and diethers of glycols). The products prepared in this process are useful for preparing adhesives with water, as color developers, as flow and leveling improvers in latex paints and as thickeners for various food products.
229368
Krumel Karl L.
May James A.
Stanley Frederick W. (jr.)
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