| 摘要 |
<p>An aqueous gellable composition having a delayed gelling time presettable within wide time and temperature ranges, contains a water-soluble organic polymer crosslinkable with chrome ion and a crosslinking/retardant system definable by the formula: Cr(L)m.nL' wherein: Cr is a trivalent chrome ion; L is an organic ligand consisting of a monocarboxylate or dicarboxylate ion, optionally bearing one or more amino or hydroxy functional group(s), in form complexed with chrome ion; L' is an organic ligand consisting of a monocarboxy or dicarboxy acid, optionally bearing one or more amino or hydroxy functional group(s), in form not complexed with chrome ion; m has a value comprised within the range of from 1 to 3, depending on the nature of the ligand L; n has a value comprised within the range of from 0.5 to 100; with the proviso that in the crosslinking/retardant system, the ligand L is different from the ligand L'.</p> |
