Patent ID: 6482881
Filing Date: 2002-11-19
Classification: C01B,C08K,G03G

Abstract:
An inorganic dispersant which comprises particles of a calcium phosphate compound and/or a calcium phosphate-calcium carbonate composite having a petaloid porous structure and an atomic ratio Ca/P of not more than 16.7, said particles satisfying the following formulas (a) to (g):0.1&lE;dx1&lE;20(&mgr;m),â€ƒâ€ƒ(a) 1&lE;&agr;&lE;5, where &agr;=d50/dx1,â€ƒâ€ƒ(b) 0&lE;&bgr;&lE;2, where &bgr;=(d90âˆ’d10)/d50,â€ƒâ€ƒ(c) 0.01&lE;dx2&lE;1(&mgr;m),â€ƒâ€ƒ(d) 95&lE;&ohgr;1&lE;99,â€ƒâ€ƒ(e) 70&lE;&ohgr;2&lE;95,â€ƒâ€ƒ(f) 50&lE;Sw1&lE;500(m2/g),â€ƒâ€ƒ(g) wherein,dx1: Average particle diameter (&mgr;m) measured by a photograph of an electron microscope; &agr;: Dispersion coefficient; d50: 50% average particle diameter (&mgr;m) measured by a particle size distribution tester using a Microtrac FRA laser; &bgr;: Sharpness; d90: 90% particle diameter of the total particles passed through a sieve measured by a particle size distribution tester using a Microtrac FRA laser; d10: 10% particle diameter of the total particles passed through a sieve measured by a particle size distribution tester using a Microtrac FRA laser; dx2: Average micropore diameter (&mgr;m) of particles measured from a micropore distribution measured by a mercury penetration method; &ohgr;1: Static percentage of voids (%) calculated from the following equation (h): Ï‰&it;1={1-12.9Ã—[apparent&it;â€ƒ&it;specific&it;â€ƒ&it;volume]}Ã—100&it;â€ƒ&it;(%)(h)â€ƒwherein the apparent specific volume (ml/g) is measured according to a static method of pigment test according to JIS K5101-91 20.1, &ohgr;2: Pressurized percentage of voids (%) calculated from the following equation (i): Ï‰&it;2={1-0.52.9Ã—2Ã—[thickness]}Ã—100&it;â€ƒ&it;(%)(i)â€ƒwherein the thickness is measured by a slide calipers after packing 0.5 g of a sample in a cylinder having a cross section of 2 cm2, pressurizing the sample with a pressure of 30 kg/cm2 for 30 seconds. Sw1: BET specific surface area m2/g by a nitrogen adsorbing method.