Patent ID: 8287952
Filing Date: 2012-10-16
Classification: B01J,Y10T

Abstract:
1. A method of making a composition comprising a colloid which is stable under physiological pH and ionic strength, said colloid comprising particles having a colloidal silica core and a shell, said method comprising the steps of: introducing into a vessel a first liquid stream containing core particles; simultaneously introducing into said vessel a second liquid stream containing a polymer made from a monomer having amine functionalities in an amount at least equal to the amount required to cover the surfaces of the core particles; and simultaneously introducing into said vessel a third liquid stream having a pH adjusting substance at such a rate that the pH in said vessel is maintained at a pH below 6.0, and subsequently readjusting the pH of the core-shell colloid to a pH between about 7-10; followed by the addition of a cross-linking reagent capable of cross-linking the polymer; and finally adjusting the pH of the colloid to approximately physiological conditions wherein the core-shell colloid contains between 10 and 30 μmol amine-monomer/m