Method to improve the stability of dispersions of carbon

• Main Authors: ROGER F BERNARDS, JOSEPH S BOWERS JR
• Format: Patent
• Language: English
• Published: 01.02.2006
• Subjects: ADHESIVES; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOIDCHEMISTRY; CHEMICAL PAINT OR INK REMOVERS; CHEMISTRY; COATING COMPOSITIONS, e.g. PAINTS, VARNISHES ORLACQUERS; CONVEYING; CORRECTING FLUIDS; DYES; ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; FILLING PASTES; HANDLING THIN OR FILAMENTARY MATERIAL; INKS; MACHINES, APPARATUS OR DEVICES FOR, OR METHODS OF, PACKAGINGARTICLES OR MATERIALS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS; METALLURGY; MISCELLANEOUS APPLICATIONS OF MATERIALS; MISCELLANEOUS COMPOSITIONS; MIXING, e.g. DISSOLVING, EMULSIFYING, DISPERSING; NATURAL RESINS; PACKING; PAINTS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; PERFORMING OPERATIONS; PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL; POLISHES; PREPARATION OF CARBON BLACK; PRINTED CIRCUITS; STORING; THEIR RELEVANT APPARATUS; TRANSPORTING; TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS,TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES; UNPACKING; USE OF MATERIALS THEREFOR; WOODSTAINS

A method for preventing a carbon dispersion from increasing in viscosity during use is described. The dispersion comprises graphite particles or carbon black particles or a combination of both dispersed in a fluid. The method involves lowering the susceptibility of the carbon dispersion to an increase in viscosity or ionic strength by lowering its pH or reducing its exposure to reactive components in the ambient atmospheric gas. The pH can be lowered by at least partially removing ammonia from the dispersion, or by adding a material that reduces the pH of the dispersion. The stability of the dispersion can also be improved by isolating the dispersion from reactive atmospheric gas. The stabilized aqueous carbon dispersion can have a viscosity of less than about 20 cps and a conductivity of less than about 3 mS.