Dry grinding aid for dry milling a calcined kaolin clay and a related method
AssigneeECC International Limited
InventorsWilliam H. Pope, Raymond Brock McNeely
Life of this patent
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Abstract
An improved method for dry milling calcined kaolin clays involves use of an effective amount of an ammonium polyacrylate dry grinding aid which is applied to a calcined kaolin clay product prior to dry milling. This improves flowability of the product through the mill, resulting in an increase in the grinding efficiency and, therefore, an increase in the production rate of the mill. The final product displays an increase in Hercules high shear viscosity, and therefore, an increase in the rheology in very high solids aqueous slurries, which is particularly useful in the coating of paper and paperboard products.
Claims17
A method for dry milling a dry calcined kaolin clay powder in a media mill, comprising:
- a) introducing said dry calcined kaolin clay powder into said media mill, and
- b) prior to or simultaneously with step a), applying a dry grinding aid onto said dry calcined powder to at least improve the flowability characteristic of said dry powder through said mill.
In a method for preparing a dry calcined kaolin clay powder having good high shear rheology when in high solids aqueous slurries, thereby facilitating its use in coating and in the preparation of coating colors and providing high gloss, high brightness, and good opacity and printability characteristics in the papers to which it is applied, the improvement comprising:
- a) introducing said dry calcined kaolin clay powder into a media mill, and
- b) prior to or simultaneously with step a), applying onto said dry calcined kaolin clay powder a dry grinding aid selected from the group consisting of polyacrylate dispersants to at least improve the flowability characteristics of said dry powder through aid mill.
In a method for increasing the production rate of a dry calcined kaolin clay powder in a media mill, the improvement comprising:
- applying a dry grinding aid selected from the group consisting of polyacrylate dispersants onto said calcined kaolin clay powder upon introduction of said calcined kaolin clay powder into said media mill to at least improve the flow characteristics of said dry powder through said mill.
A coating color for coating paper, which provides high gloss, high brightness, and good opacity and printability characteristics in the papers to which it is applied comprising:
- a dry calcined kaolin clay powder which has been dry milled in a media mill in the presence of a dry grinding aid selected from the group consisting of polyacrylate dispersants which at least improves the flow characteristics of said dry powder through the mill.
Dependencies are inferred from the claim text.