Hydrotalcite loaded with dye anions has a defined soluble salt content, particle size and dye loading

摘要

#CMT# #/CMT# Hydrotalcite loaded with dye anions has a soluble salt content of less than 3 wt.%, a particle size of 0.02-0.6 mu m and a dye loading such that at least 70% of the neutralizable positively charged sites are loaded with dye anions. The x-ray diffraction pattern has no significant reflections that would indicate an interplanar spacing other than that corresponding to intercalated dye ions. #CMT# : #/CMT# Independent claims are also included for: (1) producing hydrotalcites in which soluble salts are removed after separating the hydrotalcite from the liquid phase by suspending the solid material in water, stirring the suspension for at least 1 hour and separating the solid from the liquid, this procedure being carried out at least three times; (2) producing hydrotalcites with intercalated chloride ions by exposing a dry hydrotalcite with intercalated carbonate ions to hydrogen chloride gas. #CMT#USE : #/CMT# Pigments and paper coating are mentioned. #CMT#ADVANTAGE : #/CMT# The dye-loaded hydrotalcite has a fine particle size, a high dye loading, good crystallinity and high transparency. #CMT#EXAMPLE : #/CMT# Dried hydrotalcite (1 g) was suspended in water and the suspension was stirred to fully hydrate the hydrotalcite, A solution of naphthol yellow was added in an amount corresponding to three times the number of intercalating sites in the hydrotalcite. After equilibration for 3 days, the solid was centrifuged, redispersed in water and centriguged three times, and dried in vacuo for 4 hours.