| 摘要 |
<PICT:0967751/C3/1> A denture adhesive composition consists essentially by weight of 20-95% hydroxyethyl cellulose having an average degree of substitution of ethylene oxide groups per anhydroglucose unit of 0.4-4.5; 0-75% of an alkyl cellulose selected from the group consisting of methyl cellulose having an average degree of substitution (D.S.) of 1.4-2.6, ethyl cellulose having an average D.S of 0.8-1.9, and a hydroxyethylmethyl cellulose or hydroxypropylmethyl cellulose having an average D.S. for hydroxyethyl or hydroxypropyl groups of 0.1-0.5 and for methyl groups of 1.0-2.5; and 0-20% of monomer-free polyacrylamide. Preferred compositions may contain a major proportion of hydroxyethyl cellulose having an average D.S. of 0.4-4.5, especially 1.5-3.0. Such hydroxyethyl cellulose, in 2% by weight aqueous solution, may have a viscosity of 1000-6000 cps. at 20 DEG C. Another preferred composition contains 25-90% especially 45-90% of hydroxyethyl cellulose of average D.S. 0.4-4.5, and 10-75% especially 10-55% of a methyl or ethyl cellulose, the composition having in 2% aqueous solution a viscosity of 2000-6000 cps. at 20 DEG C. Up to 20% of this mixture may be replaced by a polyacrylamide having in 2% aqueous solution a viscosity of 500-3000 cps. at 20 DEG C. Another preferred composition consists essentially of hydroxyethyl cellulose of average D.S. 0.4-4.5, methyl cellulose of viscosity (in 2% aqueous solution) 2000-6000 cps. at 20 DEG C.; and a polyacrylamide of viscosity 800-3000 cps. under the same conditions, in such proportions as to be represented by a point in the triaxial diagram of Fig. 1, lying within the area 1, 4, 5, 6, and preferably within the area 7, 8, 9, 10. The composition may be used in the form of a paste of 50% of the dry composition and 50% water, or the powdered composition may be incorporated in an inert paste-forming carrier, suitably in a ratio of from 1:3 to 3:1, or in an oleaginous vehicle e.g. cocoa butter. U.S.A. Specification 2,064,402 is referred to.
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