A process for preparing organoclays as thixotropic agents to control the rheology of water-based paints and other aqueous and polar-organic systems. The process relates to treating low-grade clay ores to achieve highly purified organoclays and/or to incorporate surface modifying agents onto the clay...http://www.google.co.uk/patents/US6172121?utm_source=gb-gplus-sharePatent US6172121 - Process for preparing organoclays for aqueous and polar-organic systems
