Dentifrice-compatible silica particulates

US5614176A · kind A · utility

Assignee

• RHONE-POULENC CHIMIE · FR

Inventor

• Jacques Persello · Miribel, FR

Key dates

• Filing date: Jun 7, 1995
• Grant date: Mar 25, 1997
• Expiry date: Jun 7, 2015

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C01P2006/90
• WIPO field: Pharmaceuticals
• WIPO sector: Chemistry

Abstract

Novel silica particulates especially adapted for formulation to dentifrice compositions exhibit unique physical and chemical properties. In one embodiment, silica particulates have a unique surface chemistry as to be at least 50% compatible with zinc values, and have a number of OH functions, expressed as OH/nm.sup.2, of at most 15 and a zero charge point (PZC) of from 3 to 6.5. In a second embodiment, particulates have a surface chemistry as to be at least 65%, and preferably at least 90% compatible with guanidine values, notably chlorhexidine, and acidity function thereof, Ho, of at least 3.3. In a third embodiment, silica particulates are compatible with organic amines, and have a pH, in aqueous suspension, which varies according to the equations pH.ltoreq.7.5-0.7 log(C) and pH.gtoreq.5.0-0.5 log(C) and which also varies as a function of the electrical conductivity thereof, according to the equations pH.ltoreq.8.5-0.4 log(D) and pH.gtoreq.7.0-0.6 log(D) wherein (C) represents the weight concentration of said silica suspension, expressed % SiO.sub.2 and (D) represents the electrical conductivity of such aqueous silica suspension expressed in microsiemens.cm.sup.-1. In a fourth em…