# US 2017/0287518 A1 · Magnetic recording medium and magnetic recording medium composition > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2017/0287518 A1 - Document ID: US20170287518A1 - Status: Published application - Kind: A1 - Application number: 15/474,504 - Filed: 2017-03-30 - Published: 2017-10-05 - Earliest claimed: 2016-03-31 - Assignees: FUJIFILM Corporation - Applicants: FUJIFILM Corporation - Inventors: Toshihide AOSHIMA; Mika IMAMURA; Shinji TSUJIMOTO - Web page: https://patentgrep.com/patent/US20170287518A1 ## CPC - G11B 5/71: characterised by the lubricant - C08K 3/22: of metals - C08K 5/101: of monocarboxylic acids - G11B 5/7021: {containing a polyurethane or a polyisocyanate} - G11B 5/7023: {containing polyesters, polyethers, silicones, polyvinyl resins, polyacrylresins or epoxy resins (G11B5/7022 takes precedence)} - G11B 5/714: characterised by the dimension of the magnetic particles - C08K 2003/2272: {Ferric oxide (Fe2O3)} - G11B: INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER (recording measured values in a way that does not require playback through a transducer G01D9/00; recording or playback apparatus using mechanically marked tape, e.g. punched paper tape, or using unit records, e.g. punched or magnetically marked cards G06K; transferring data from one type of record carrier to another G06K1/18; circuits for coupling output of reproducer to radio receiver H04B1/20; gramophone pick-ups or like acoustic electromechanical transducers or circuits therefor H04R) - C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09) ## Abstract The magnetic recording medium contains, in a magnetic layer, a fatty acid ester and a polyester resin having a number average molecular weight of greater than or equal to 1,000 but less than 20,000, and containing a structural unit derived from a polyvalent carboxylic acid and a structural unit derived from a polyol, as well as 10 mol % to 50 mol % of a structural unit, derived from a cyclic polyvalent carboxylic acid selected from the group consisting of an alicyclic polyvalent carboxylic acid and an aromatic polyvalent carboxylic acid, per 100 mol % of a combined total of the above structural units, and one or more partial structures selected from the group consisting of the following partial structures: wherein each of L1 and L2 independently denotes a divalent connecting group, and each of Z1 and Z2 independently denotes a monovalent group denoted by —OM or a monovalent group denoted by —O−A+. ## Claims ### Claim 1 A magnetic recording medium, which comprises a magnetic layer comprising ferromagnetic powder and binder on a nonmagnetic support, wherein: the magnetic layer further comprises a fatty acid ester and a polyester resin with a number average molecular weight of greater than or equal to 1,000 but less than 20,000; the polyester resin comprises a structural unit derived from a polyvalent carboxylic acid and a structural unit derived from a polyol, as well as 10 mol % to 50 mol % of a structural unit, derived from a cyclic polyvalent carboxylic acid selected from the group consisting of an alicyclic polyvalent carboxylic acid and an aromatic polyvalent carboxylic acid, per 100 mol % of a combined total of the structural unit derived from the polyvalent carboxylic acid and the structural unit derived from the polyol; and the polyester resin comprises one or more partial structures selected from the group consisting of a partial structure denoted by formula 1 and a partial structure denoted by formula 2 below: wherein each of L1 in formula 1 and L2 in formula 2 independently denotes a divalent connecting group, and each of Z1 in formula 1 and Z2 in formula 2 independently denotes a monovalent group denoted by —OM or a monovalent group denoted by —O−A+, with M denoting a hydrogen atom or an alkali metal atom, A+ denoting an ammonium cation, and * denoting a bond position with another partial structure constituting the polyester resin. ### Claim 2 (depends on 1) The magnetic recording medium according to claim 1, wherein the divalent connecting group is an alkylene group having 1 to 10 carbon atoms, an alkenylene group having 2 to 10 carbon atoms, or an aromatic group having 6 to 12 carbon atoms. ### Claim 3 (depends on 1) The magnetic recording medium according to claim 1, wherein the divalent connecting group is an alkylene group having 1 to 10 carbon atoms. ### Claim 4 (depends on 1) The magnetic recording medium according to claim 1, wherein the divalent connecting group is an alkenylene group having 2 to 10 carbon atoms. ### Claim 5 (depends on 1) The magnetic recording medium according to claim 1, wherein the divalent connecting group is an aromatic group having 6 to 12 carbon atoms. ### Claim 6 (depends on 1) The magnetic recording medium according to claim 1, wherein the magnetic layer comprises 0.5 to 50.0 weight parts of the polyester resin per 100.0 weight parts of ferromagnetic powder. ### Claim 7 (depends on 1) The magnetic recording medium according to claim 1, wherein the binder is one or more resins selected from the group consisting of a polyurethane resin and a vinyl chloride resin. ### Claim 8 (depends on 1) The magnetic recording medium according to claim 1, wherein an average particle size of the ferromagnetic powder falls within a range of 10 nm to 50 nm. ### Claim 9 A composition, which is a magnetic recording medium composition comprising ferromagnetic powder, binder, a fatty acid ester, and a polyester resin with a number average molecular weight of greater than or equal to 1,000 but less than 20,000, wherein: the polyester resin comprises a structural unit derived from a polyvalent carboxylic acid and a structural unit derived from a polyol, as well as 10 mol % to 50 mol % of a structural unit, derived from a cyclic polyvalent carboxylic acid selected from the group consisting of an alicyclic polyvalent carboxylic acid and an aromatic polyvalent carboxylic acid, per 100 mol % of a combined total of the structural unit derived from the polyvalent carboxylic acid and the structural unit derived from the polyol; and the polyester resin comprises one or more partial structures selected from the group consisting of a partial structure denoted by formula 1 and a partial structure denoted by formula 2 below: wherein each of L1 in formula 1 and L2 in formula 2 independently denotes a divalent connecting group, and each of Z1 in formula 1 and Z2 in formula 2 independently denotes a monovalent group denoted by —OM or a monovalent group denoted by —O−A+, with M denoting a hydrogen atom or an alkali metal atom, A+ denoting an ammonium cation, and * denoting a bond position with another partial structure constituting the polyester resin. ### Claim 10 (depends on 9) The composition according to claim 9, wherein the divalent connecting group is an alkylene group having 1 to 10 carbon atoms, an alkenylene group having 2 to 10 carbon atoms, or an aromatic group having 6 to 12 carbon atoms. ### Claim 11 (depends on 9) The composition according to claim 9, wherein the divalent connecting group is an alkylene group having 1 to 10 carbon atoms. ### Claim 12 (depends on 9) The composition according to claim 9, wherein the divalent connecting group is an alkenylene group having 2 to 10 carbon atoms. ### Claim 13 (depends on 9) The composition according to claim 9, wherein the divalent connecting group is an aromatic group having 6 to 12 carbon atoms. ### Claim 14 (depends on 9) The composition according to claim 9, which comprises 0.5 to 50.0 weight parts of the polyester resin per 100.0 weight parts of ferromagnetic powder. ### Claim 15 (depends on 9) The composition according to claim 9, wherein the binder is one or more resins selected from the group consisting of a polyurethane resin and a vinyl chloride resin. ### Claim 16 (depends on 9) The composition according to claim 9, wherein an average particle size of the ferromagnetic powder falls within a range of 10 nm to 50 nm.