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US 3,953,421 AGranted
Paper coating compositions and organic pigments used therein
AssigneeCabot Corporation
InventorGregor Berstein
Life of this patent
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AssigneeCabot Corporation
InventorGregor Berstein
Estimating the term…
Improved aqueous slurry type coating colors for coating of paper, paperboard and the like are described in which there is incorporated along with the usual finely divided inorganic pigments, such as clay, an auxiliary pigment consisting of a substantially water-insoluble, cross-linked urea-formaldehyde pigment in highly dispersed particulate form. The urea-formaldehyde pigment constitutes from about 2 to 25% and preferably from about 3 to about 15% by weight of the total pigment solids in the coating colors. The BET specific surface area of the particulate urea-formaldehyde pigments ranges from about 40 to about 75 square meters per gram in which instance the average agglomerate size of the pigments ranges from about 2 to about 3.5 microns. In those instances where the BET specific surface area of the urea-formaldehyde pigments ranges from at least 15 to 40 square meters per gram, the average agglomerate size of the pigments ranges from about 2 to about 4 microns.
In a conventional coating color composition suitable for coating paper, paperboard and the like comprising a suitable polymeric binder dissolved or dispersed in an aqueous slurry of finely divided pigment solids, the principal proportion of which by weight are inorganic pigments of less than 2 microns in mean particle size, the improvement which comprises said pigment solids, in an amount of from about 2 to about 25% by weight based upon the total weight of pigment solids employed in the coating color composition, being an essentially water-insoluble, infusible, non-porous, cross-linked urea-formaldehyde pigment in a highly dispersed particulate form having a molar ratio of urea to formaldehyde ranging from about 1:1.3 to about 1:1.8, a BET specific surface area of from about 40 to about 75 square meters per gram, and a mean agglomerate size of from about 2 to about 3.5 microns.
In a conventional coating color composition suitable for coating paper, paperboard and the like comprising a suitable polymer binder dissolved or dispersed in an aqueous slurry of finely divided pigment solids, the principal proportion of which by weight are inorganic pigments of less than 2 microns in mean particle size, the improvement which comprises said pigment solids, in an amount of from about 2 to about 25% by weight based upon the total weight of pigment solids employed in the coating color composition, being an essentially water-insoluble, infusible, non-porous, cross-linked urea-formaldehyde pigment in a highly dispersed particulate form having a molar ratio of urea to formaldehyde ranging from about 1:1.3 to about 1:1.8, a BET specific surface area of from at least 15 to 40 square meters per gram, and a mean agglomerate size of from about 2 to about 4.0 microns.
Dependencies are inferred from the claim text.