REVERSIBLY THERMALLY GELABLE CELLULOSE ETHER GEL, AND IMPROVEMENT IN SPEED OF REVERSIBLE THERMAL GELATION RESPONSE OF CELLULOSE ETHER

摘要

PROBLEM TO BE SOLVED: To obtain a reversibly thermally responsive gel improved in speed of reversible gelation response to heat by adding a suitable amt. of sodium sulfate to an aq. soln. of an alkyl (hydroxyalkyl) cellulose which aq. soln. gels when heated but becomes the aq. soln. when cooled. ;SOLUTION: This gel is a cellulose ether gel which is capable of reversibly responding to heat, and is improved in speed of reversible response to heat by lowering the thermal gelation temp. thereof and decreasing a temp. difference between it and the temp. at which it is restored to an aq. soln. Sodium sulfate in an amount of 0.1-5.0wt.% is added to an aq. soln. of an alkyl cellulose or a hydroxyalkyl alkyl cellulose in the course of preparation of a desired aq. soln. Examples of the alkyl cellulose include methyl cellulose, while examples of the hydroxyalkyl alkyl cellulose include hydroxypropyl methyl cellulose. In the figure, the thermal gelation temp. is T₁ at which gelation begins, while T₂ is the temp. at which the gel is restored to the aq. soln. The hysteresis width is a temp. difference between T₀ and T₂, which is pref. as small as possible.;COPYRIGHT: (C)1997,JPO