# US 7,744,688 B2 · Paper coating pigments > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,744,688 B2 - Document ID: US7744688B2 - Status: Granted - Kind: B2 - Application number: 10/538,012 - Filed: 2003-12-29 - Published: 2006-12-28 - Granted: 2010-06-29 - Earliest claimed: 2002-12-27 - Assignees: Imerys Pigments, Inc. - Inventors: David Skuse; Mark Mortimer; Deb Thrale; Rajan R. Iyer; Daniel J. Panfil; Christopher Nutbeem - Web page: https://patentgrep.com/patent/US7744688B2 ## CPC - C09C 1/42: Clays - C09C 1/021: {Calcium carbonates} - D21H 19/38: characterised by the pigments - D21H 19/385: {Oxides, hydroxides or carbonates} - C01P 2004/51: Particles with a specific particle size distribution - C01P 2004/54: Particles characterised by their aspect ratio, i.e. the ratio of sizes in the longest to the shortest dimension - C01P 2004/61: Micrometer sized, i.e. from 1-100 micrometer - C01P 2004/62: Submicrometer sized, i.e. from 0.1-1 micrometer - C01P 2006/22: Rheological behaviour as dispersion, e.g. viscosity, sedimentation stability - C01P 2006/60: Optical properties, e.g. expressed in CIELAB-values - D21H 19/40: siliceous, e.g. clays - D21H 21/52: Additives of definite length or shape - C09C: TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS, TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES (treatment of materials specially adapted to enhance their filling properties in mortars, concrete or artificial stone C04B14/00, C04B18/00, C04B20/00); PREPARATION OF CARBON BLACK {; PREPARATION OF INORGANIC MATERIALS WHICH ARE NO SINGLE CHEMICAL COMPOUNDS AND WHICH ARE MAINLY USED AS PIGMENTS OR FILLERS} - D21H: PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR - C01P: INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS ## Abstract The present disclosure relates to a coating composition for use in producing a coating on paper and other substrates comprising an aqueous suspension of a particulate pigment together with a binder, wherein the particulate pigment comprises a mixture of: a first pigment component comprising particulate ground calcium carbonate (GCC) having a particle size distribution (psd) steepness factor ranging from about 30 to about 45; and a second pigment component comprising particulate precipitated calcium carbonate (PCC) having a psd steepness factor ranging from about 55 to about 75. The particulate pigment may optionally further include a particulate kaolin clay. ## Claims ### Claim 1 A composition comprising: a first pigment component comprising particulate ground calcium carbonate (GCC) having a particle size distribution (psd) steepness factor ranging from less than 36 to about 30; and a second pigment component comprising particulate precipitated calcium carbonate (PCC) having a psd steepness factor ranging from about 55 to about 75 and a d50 not greater than 0.5 μm. ### Claim 2 (depends on 1) A composition according to claim 1, wherein the first and second component particles are present in an amount such that the weight ratio of the first component particles to the second component particles ranges from about 5:95 to about 95:5. ### Claim 3 (depends on 2) A composition according to claim 2, wherein the weight ratio of the first component particles to the second component particles ranges from about 10:90 to about 90:10. ### Claim 4 (depends on 3) A composition according to claim 3, wherein the weight ratio of the first component particles to the second component particles ranges from about 30:70 to about 70:30. ### Claim 5 (depends on 1) A composition according to claim 1, further comprising a kaolin clay. ### Claim 6 (depends on 5) A composition according to claim 5, wherein said kaolin clay is present in an amount such that the weight ratio of the first and second calcium carbonate pigments to the kaolin clay is at least about 10:90. ### Claim 7 (depends on 6) A composition according to claim 6, wherein the weight ratio is at least about 70:30. ### Claim 8 (depends on 1) A composition according to claim 1, wherein said composition is a pigment in the form of a dry particulate mixture. ### Claim 9 (depends on 1) A composition according to claim 1, wherein said composition is a pigment in the form of a suspension of said particles in a liquid medium. ### Claim 10 (depends on 1) A composition according to claim 1, wherein said composition is a pigment for paper and other substrates. ### Claim 11 (depends on 1) A composition according to claim 1, wherein the second pigment component comprises PCC having a d50 of less than 0.5 μm. ### Claim 12 (depends on 1) A composition according to claim 1, wherein the second pigment component comprises PCC having a d50 of less than 0.45 μm. ### Claim 13 (depends on 1) A composition according to claim 1, wherein the second pigment component comprises PCC having a d50 of less than 0.40 μm. ### Claim 14 (depends on 1) A composition according to claim 1, wherein the second pigment component comprises PCC having a d50 of less than 0.35 μm. ### Claim 15 (depends on 1) A composition according to claim 1, wherein the second pigment component comprises PCC having a d50 ranging from 0.2 μm to 0.5 μm. ### Claim 16 (depends on 1) A composition according to claim 1, wherein the second pigment component comprises PCC having a d50 ranging from 0.3 μm to 0.5 μm. ### Claim 17 (depends on 1) A composition according to claim 1, wherein the second pigment component comprises PCC having a d50 of about 0.4 μm. ### Claim 18 (depends on 1) A composition according to claim 1, wherein the composition consists essentially of the first pigment component and the second pigment component; the first pigment component consists essentially of the GCC and the second pigment component consists essentially of the PCC. ### Claim 19 A coating composition comprising an aqueous suspension of at least one particulate pigment and at least one binder, wherein the particulate pigment comprises a mixture of: a first pigment component comprising particulate ground calcium carbonate (GCC) having a particle size distribution (psd) steepness factor ranging from less than 36 to about 30; and a second pigment component comprising particulate precipitated calcium carbonate (PCC) having a psd steepness factor ranging from about 55 to about 75 and a d50 not greater than 0.5 μm. ### Claim 20 (depends on 19) A coating composition according to claim 19, wherein the pigment is for paper and other substrates. ### Claim 21 (depends on 19) A coating composition according to claim 19, wherein the at least one binder is present in an amount ranging from about 4% to about 30% of the solids of the composition on a dry weight basis. ### Claim 22 (depends on 19) A coating composition according to claim 19, wherein the at least one binder comprises a modified starch. ### Claim 23 (depends on 19) A coating composition according to claim 19, wherein the at least one binder comprises an unmodified starch. ### Claim 24 (depends on 22) A coating composition according to claim 22, wherein the at least one binder comprises a component other than starch. ### Claim 25 (depends on 19) A coating composition according to claim 19, further comprising: one or more cross linkers; one or more water retention aids; one or more viscosity modifiers and/or thickeners; one or more lubricity/calendering aids; one or more dispersants; one or more antifoamers/defoamers; one or more dry or wet pick improvement additives; one or more dry or wet rub improvement and/or abrasion resistance additives; one or more gloss-Ink hold-out additives; one or more optical brightening agents (OBA) and/or fluorescent whitening agents (FWA); one or more dyes; one or more biocides/spoilage control agents; one or more leveling and evening aids; one or more grease and oil resistance additives; one or more water resistance additives; one or more additional pigments; or any combination thereof. ### Claim 26 (depends on 19) A coating composition according to claim 19, further comprising an optional component in an amount of less than about 10% by weight, relative to the total weight of the composition. ### Claim 27 (depends on 19) A coating composition according to claim 19, wherein the second pigment component comprises PCC having a d50 of less than 0.5 μm. ### Claim 28 (depends on 19) A coating composition according to claim 19, wherein the second pigment component comprises PCC having a d50 of less than 0.45 μm. ### Claim 29 (depends on 19) A coating composition according to claim 19, wherein the second pigment component comprises PCC having a d50 of less than 0.40 μm. ### Claim 30 (depends on 19) A coating composition according to claim 19, wherein the second pigment component comprises PCC having a d50 of less than 0.35 μm. ### Claim 31 (depends on 19) A coating composition according to claim 19, wherein the second pigment component comprises PCC having a d50 ranging from 0.2 μm to 0.5 μm. ### Claim 32 (depends on 19) A coating composition according to claim 19, wherein the second pigment component comprises PCC having a d50 ranging from 0.3 μm to 0.5 μm. ### Claim 33 (depends on 19) A coating composition according to claim 19, wherein the second pigment component comprises PCC having a d50 of about 0.4 μm. ### Claim 34 (depends on 19) A coating composition according to claim 19, wherein the coating composition consists essentially of the aqueous suspension of the at least one particulate pigment and the at least one binder, and wherein the at least one particulate pigment consists essentially of the mixture of the first pigment component and the second pigment component and wherein the first pigment component consists essentially of the particulate GCC, and the second pigment component consists essentially of the particulate PCC. ### Claim 35 A method for preparing a coating composition comprising mixing at least one particulate pigment comprising a mixture of: a first pigment component comprising particulate ground calcium carbonate (GCC) having a particle size distribution (psd) steepness factor ranging from less than 36 to about 30; and a second pigment component comprising particulate precipitated calcium carbonate (PCC) having a psd steepness factor ranging from about 55 to about 75 and a d50 not greater than 0.5 μm, and at least one binder into an aqueous liquid medium and then preparing a suspension of the solid components therein. ### Claim 36 A method for preparing a coated product, comprising applying to said product a composition comprising an aqueous suspension of at least one particulate pigment and at least one binder, wherein the particulate pigment comprises a mixture of: a first pigment component comprising particulate ground calcium carbonate (GCC) having a particle size distribution (psd) steepness factor ranging from less than 36 to about 30; and a second pigment component comprising particulate precipitated calcium carbonate (PCC) having a psd steepness factor ranging from about 55 to about 75 and a d50 not greater than 0.5 μm; further comprising calendering said product to form a coating thereon. ### Claim 37 (depends on 36) A method according to claim 36, wherein said product is in the form of paper, board, card, or paper board. ### Claim 38 A product coated with a coating comprising a dry residue of a composition comprising an aqueous suspension of at least one particulate pigment and at least one binder, wherein the particulate pigment comprises a mixture of: a first pigment component comprising particulate ground calcium carbonate (GCC) having a particle size distribution (psd) steepness factor ranging from less than 36 to about 30; and a second pigment component comprising particulate precipitated calcium carbonate (PCC) having a psd steepness factor ranging from about 55 to about 75 and a d50 not greater than 0.5 μm. ### Claim 39 (depends on 38) A product according to claim 38, wherein said product is in the form of paper, board, card, or paper board. ### Claim 40 (depends on 5) A composition according to claim 5, wherein said kaolin clay has a d50 of greater than or equal to about 0.5 μm. ### Claim 41 (depends on 5) A composition according to claim 5, wherein said kaolin clay has a d50 less than about 0.5 μm. ### Claim 42 (depends on 40) A composition according to claim 40, wherein said kaolin clay has a d50 ranging from about 0.5 μm to about 1.5 μm. ### Claim 43 (depends on 41) A composition according to claim 41, wherein said kaolin clay has a d50 ranging from about 0.1 μm to about 0.5 μm. ### Claim 44 (depends on 5) A composition according to claim 5, wherein said kaolin clay has a shape factor greater than about 25. ### Claim 45 (depends on 5) A composition according to claim 5, wherein said kaolin clay has a shape factor greater than about 30. ### Claim 46 (depends on 5) A composition according to claim 5, wherein said kaolin clay has a shape factor greater than about 45. ### Claim 47 (depends on 5) A composition according to claim 5, wherein said kaolin clay has a shape factor less than about 25. ### Claim 48 (depends on 5) A composition according to claim 5, wherein said kaolin clay has a shape factor ranging from about 5 to about 20. ### Claim 49 (depends on 5) A composition according to claim 5, wherein said kaolin clay has a shape factor less than about 25 and a d50 less than about 0.5 μm. ### Claim 50 (depends on 5) A composition according to claim 5, wherein said kaolin clay has a steepness greater than about 20. ### Claim 51 (depends on 5) A composition according to claim 5, wherein said kaolin clay has a steepness ranging from about 25 to about 45. ### Claim 52 (depends on 23) A coating composition according to claim 23, wherein the at least one binder comprises a component other than starch. ### Claim 53 (depends on 25) A coating composition according to claim 25, further comprising an optional component in an amount of less than about 10% by weight, relative to the total weight of the composition.