| 摘要 |
<p>Set retarded calcium sulphate hemihydrate comprises, as set retardant, a water-soluble cellulose ether containing both non-ionic and ionic etherifying substituent groups in the cellulose chain, the degree of substitution of the ether by the ionic group being such that the ether does not form an insoluble calcium salt in the presence of a saturated solution of calcium hydroxide. In examples, plaster mixes are given containing hydrated lime powder. Specification 988,302 is referred to.</p> |
