# US 5,344,483 A · High-density, low-viscosity ink for use in ink jet printers > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,344,483 A - Document ID: US5344483A - Status: Granted - Kind: A - Application number: 07/860,098 - Filed: 1992-03-30 - Granted: 1994-09-06 - Earliest claimed: 1992-03-30 - Assignees: Porelon, Inc. - Inventors: Stephanie S. Hinton - Web page: https://patentgrep.com/patent/US5344483A ## CPC - C09D 11/36: based on non-aqueous solvents - C09D: COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR (cosmetics A61K; processes for applying liquids or other fluent materials to surfaces, in general, B05D; staining wood B27K5/02; glazes or vitreous enamels C03C; natural resins, French polish, drying-oils, driers, turpentine, per se, C09F; polishing compositions other than French polish, ski waxes C09G; adhesives or use of materials as adhesives C09J; materials for sealing or packing joints or covers C09K3/10; materials for stopping leaks C09K3/12; processes for the electrolytic or electrophoretic production of coatings C25D) ## Abstract An ink composition suitable for ink jet printing is made from a fatty acid ester base and a diluent, wherein the base consists essentially of a fatty acid which is liquid at room temperature, a polyalkylene glycol, and a dye which has been reacted with the fatty acid to form an ester. The base is combined with a compatible diluent, such as an alcohol having a low-viscosity and low vapor pressure, to provide an ink composition especially suited for ink jet dot printing of high-definition symbols such as bar codes. The ink of the invention resists spreading on rough surfaces, and thus can be used to print bar codes directly on the sides of paperboard cartons. ## Claims ### Claim 1 An ink composition suitable for ink jet printing consisting essentially of a fatty acid ester base and a diluent, wherein the base consists essentially of a fatty acid which is liquid at room temperature, a polyalkylene glycol, and a dye which has been reacted substantially completely with the fatty acid to form an ester, wherein the ink composition is essentially free of water, and the water resulting from the esterification having been eliminated in order to drive the esterification reaction substantially to completion. ### Claim 2 (depends on 1) The ink composition of claim 1, wherein the base consists essentially of 30 to 90 wt. % of the fatty acid, 10 to 50 wt. % of the polyalkylene glycol, the polyalkylene glycol having an average molecular weight of at least about 200, and 5 to 40 wt. % of the dye, and the diluent is an alcohol having a viscosity of about 10 cps or less at 20.degree. C. and a vapor pressure of about 0.06 mmHg or less at 20.degree. C. ### Claim 3 (depends on 2) The composition of claim 2, wherein the fatty acid consists essentially of one or more C.sub.17 -C.sub.19 fatty acids. ### Claim 4 (depends on 3) The composition of claim 3, wherein the ink composition consists essentially of about 30 to 70 wt. % of the base and 70 to 30 wt. % of the diluent. ### Claim 5 (depends on 4) The composition of claim 4, wherein the fatty acid consists essentially of oleic acid. ### Claim 6 (depends on 4) The composition of claim 4, wherein the fatty acid consists essentially of isostearic acid. ### Claim 7 (depends on 4) The composition of claim 4, wherein the polyalkylene glycol is a polyethylene glycol of the formula HO--CH.sub.2 CH.sub.2 --(CH.sub.2 CH.sub.2 O).sub.n --CH.sub.2 CH.sub.2 --OH, wherein n is from 1 to 14. ### Claim 8 (depends on 7) The composition of claim 7, wherein the base further comprises 0.1 to 1 wt. % of an antioxidant effective to suppress heat-initiated oxidation of the fatty acid. ### Claim 9 (depends on 8) The composition of claim 8, wherein the antioxidant is a phenolic compound. ### Claim 10 (depends on 7) The composition of claim 7, wherein the dye is a nigrosine base dye, and the fatty acid:dye weight ratio is at least about 1.5:1. ### Claim 11 (depends on 10) The composition of claim 10, wherein the diluent is a glycol ether. ### Claim 12 (depends on 11) The composition of claim 11, wherein the diluent is an alkoxytriglycol. ### Claim 13 (depends on 12) The composition of claim 12, wherein the diluent consists essentially of methoxytriglycol. ### Claim 14 (depends on 1) The composition of claim 1, wherein the ink composition has been made by: forming a mixture of the fatty acid which is liquid at room temperature, the polyalkylene glycol, and the dye capable of reacting with the fatty acid to form an ester; heating the resulting mixture to a temperature sufficient to cause the dye and fatty acid to react with each other to form the ester and for a time sufficient to drive off excess water from the mixture so that the ink composition is substantially free of water; and then combining the mixture with the diluent to form the ink composition. ### Claim 15 (depends on 14) The composition of claim 14, wherein the mixture is heated to a temperature of at least about 100.degree. C. for at least about 30 minutes. ### Claim 16 An ink composition consisting essentially of 30 to 70 wt. % of an oleate or isostearate base and the balance is essentially a glycol ether diluent, wherein the base consists essentially of: 40 to 75 wt. % of oleic or isostearic acid; 10 to 30 wt. % of a polyethylene glycol of the formula HO--CH.sub.2 CH.sub.2 --(CH.sub.2 CH.sub.2 O).sub.n --CH.sub.2 CH.sub.2 --OH, wherein n is at least 1, and having an average molecular weight of from about 200 to 600; 20 to 35 wt. % of a dye which has been reacted substantially completely with the acid to form an ester; and up to 1 wt. % of an antioxidant effective to suppress heat-initiated oxidation of the acid; and wherein the ink composition is substantially free of water, the water resulting from the esterification having been eliminated in order to drive the esterification reaction substantially to completion. ### Claim 17 (depends on 16) The composition of claim 16, wherein the dye consists essentially of Solvent Black 7. ### Claim 18 (depends on 17) The composition of claim 17, wherein the diluent consists essentially of methoxytriglycol. ### Claim 19 (depends on 16) The composition of claim 16, wherein the ink composition has been made by: forming a mixture of the oleic or isostearic acid, the polyethylene glycol, and the dye; heating the resulting mixture to at least about 100.degree. C. for at least about 30 minutes to cause the dye and acid to react with each other to form the ester and drive off excess water from the mixture; and then combining the mixture with the glycol ether diluent to form the ink composition. ### Claim 20 (depends on 19) The composition of claim 19, wherein the dye consists essentially of Solvent Black 7 and the diluent consists essentially of methoxytriglycol.