Kaolin pigments, their preparation and use

• Main Authors: HUSBAND JOHN CLAUDE, BROWN, JR. HARRY VINCENT, PANFIL DANIEL JOHN, GOLLEY CHRISTOPHER R. L
• Format: Patent
• Language: English
• Published: 25.03.2003
• Edition: 7
• Subjects: ADHESIVES; ARTIFICIAL STONE; CEMENTS; CERAMICS; CHEMISTRY; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDINGMATERIALS; CONCRETE; DYES; IMPREGNATING OR COATING OF PAPER; INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OFSOLID INORGANIC COMPOUNDS; INORGANIC CHEMISTRY; LIME, MAGNESIA; METALLURGY; MISCELLANEOUS APPLICATIONS OF MATERIALS; MISCELLANEOUS COMPOSITIONS; NATURAL RESINS; PAINTS; PAPER NOT OTHERWISE PROVIDED FOR; PAPER-MAKING; POLISHES; PREPARATION OF CARBON BLACK; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; PRODUCTION OF CELLULOSE; PULP COMPOSITIONS; REFRACTORIES; SLAG; TEXTILES; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS,TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES; TREATMENT OF NATURAL STONE

A pigment product suitable for use in a coating composition to provide a gloss coating on paper, the pigment product comprising a processed particulate kaolin produced from a naturally platy kaolin clay having a particle size distribution such that about 50% to 60% by weight of the particles have an esd less than 2 mum and less than 25% by weight of the particles have an esd less than 0.25 mum and a shape factor of at least 15. This platy clay can be blended with b-fraction clay component. In processing, the crude kaolin is ground to a shape factor greater than 50 to produce even greater "platy" clay. The pigment product has a particle size distribution such that at least 80% by weight of the particles have an esd less than 2 mum and greater than 12% and less than 35% by weight of the particles have an esd less than 0.25 mum and whose surface area is greater than 12 m2/g when measured by the BET method.