Glucoside and acrylic copolymer dispersant composition

#The present invention relates to compositions and, in particular, to compositions which can be used to prepare dispersions of solids in an aqueous medium.

#For many applications it is desirable to form dispersions of solids in an aqueous medium. The dispersions thus formed may be used to form coatings of the solid onto a surface. A number of solids are difficult to disperse or, if dispersed, give a dispersion which gives an unsatisfactory coating of the solid onto a surface. It is known to use surface active materials to assist in the formation of the dispersion but even when using surface active materials some solids are difficult to disperse or, if dispersed, give an unsatisfactory coating. This is undesirable, especially when coating a wax former to produce a ceramic mould for the formation of complex metal castings which are suitable for use in the automobile and aerospace industry. Accordingly there remains a need to provide improved materials for the formation of dispersions. We have now found that improved dispersing properties can be obtained using a mixture of materials and, in particular, a mixture of specific materials can provide an especially useful effect.

#According to the present invention there is provided a composition comprising

#Slurries based on zirconium silicate were prepared using one or more additives.

#A surfactant, or a mixture of surfactants, was mixed with a slurry of silica in water containing 30% by weight of silica. In the preparations of Example 1, 2 and Comparative Example E n-hexanol was then added to the mixture whilst continuing to stir. Zirconium silicate and cobalt aluminate were then added to the mixture whilst continuing to stir at 500 r.p.m. The mixture was then subjected to vigorous stirring and shearing for one minute using an Ultra-Turrax mixer operating at 2000 r.p.m. The viscosity of the slurry obtained was then determined.

#Each slurry was coated onto a wax and a glass plate by dipping the plate in the slurry and allowing the coated plate to dry for at least 30 minutes at ambient temperature. The appearance of the coating was assessed visually.