# US 5,702,794 A · Laminated polyester film for magnetic recording medium > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,702,794 A - Document ID: US5702794A - Status: Granted - Kind: A - Application number: 08/551,252 - Filed: 1995-10-31 - Granted: 1997-12-30 - Earliest claimed: 1992-12-17 - Assignees: Teijin Limited - Inventors: Masahiro Hosoi; Yasuhiko Saito; Yasuhiro Saeki; Masami Etchu - Web page: https://patentgrep.com/patent/US5702794A ## CPC - G11B 5/73929: {comprising naphthalene ring compounds, e.g. polyethylene naphthalate substrates} - G11B 5/73931: {Two or more layers, at least one layer being polyester} - Y10S 428/91: Product with molecular orientation - Y10T 428/24975: No layer or component greater than 5 mils thick - Y10T 428/265: 1 mil or less - Y10T 428/269: including synthetic resin or polymer layer or component - Y10T 428/31786: Of polyester [e.g., alkyd, etc.] - Y10T 428/31797: Next to addition polymer from unsaturated monomers - 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) - Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract A magnetic recording tape or disk formed from a biaxially oriented laminated polyester base film which comprises a layer (A) of a polyester consisting essentially of 2,6-naphthalenedicarboxylic acid and ethylene glycol components and a layer (B) of a copolyester consisting essentially of 2,6-naphthalenedicarboxylic acid, ethylene glycol, and diethylene glycol components, wherein the copolyester contains 1-5% by weight of the diethylene glycol component, based on the weight of the layer (B) copolyester, layer (B) being present on one or both surfaces of layer (A). ## Claims ### Claim 1 A magnetic recording medium comprising of a magnetic recording layer and a biaxially oriented laminated polyester base film wherein the base film comprises a layer (A) of a polyester consisting essentially of 2,6-naphthalenedicarboxylic acid and ethylene glycol components, and a layer (B) of a copolyester consisting essentially of 2,6-naphthalenedicarboxylic acid, ethylene glycol, and diethylene glycol components, the copolyester containing 1-5% by weight of the diethylene glycol component, based on the weight of the layer (B) copolyester, the layer (A) being provided with the layer (B) on one surface or both surfaces of layer (A). ### Claim 2 (depends on 1) A magnetic recording medium according to claim 1, wherein the magnetic layer comprises ferromagnetic particles in a vinyl acetate-vinyl chloride copolymer and polyurethane binder. ### Claim 3 A magnetic recording tape comprising of a magnetic recording layer and a biaxially oriented laminated polyester base film wherein the base film comprises a layer (A) of a polyester consisting essentially of 2,6-naphthalenedicarboxylic acid and ethylene glycol components, and a layer (B) of a copolyester consisting essentially of 2,6-naphthalenedicarboxylic acid, ethylene glycol, and diethylene glycol components, the copolyester containing 1-5% by weight of the diethylene glycol component, based on the weight of the layer (B) copolyester, the layer (A) being provided with the layer (B) on one surface or both surfaces thereof, wherein the laminated polyester film has a total thickness of 3 to 12 .mu.m and Young's moduli of at least 500 kg/mm.sup.2 in both the machine and transverse directions. ### Claim 4 (depends on 3) A magnetic recording tape according to claim 3, wherein layer (B) has a thickness of 0.1 .mu.m to one fifth of the total thickness of the laminated polyester film. ### Claim 5 (depends on 3) A magnetic recording tape according to claim 3, wherein said laminated polyester film has a Young's modulus in the machine direction of 530 to 550 and a Young's modulus in the transverse direction of 1230 to 1250 kg/mm.sup.2. ### Claim 6 (depends on 3) A magnetic recording tape according to claim 3, wherein said laminated polyester film has a bilayer structure formed of the layer (A) and the layer (B). ### Claim 7 (depends on 3) A magnetic recording tape according to claim 3, wherein said laminated polyester film has a three-layer structure formed of one layer (A) and two layers (B), the layer (A) forming a central layer. ### Claim 8 (depends on 3) A magnetic recording tape according to claim 3, wherein the magnetic layer comprises ferromagnetic particles in a vinyl acetate-vinyl chloride copolymer and polyurethane binder. ### Claim 9 A magnetic recording disk comprising of a magnetic recording layer and a biaxially oriented laminated polyester base fill wherein the base film comprises a layer (A) of a polyester consisting essentially of 2,6-naphthalenedicarboxylic acid and ethylene glycol components, and a layer (B) of a copolyester consisting essentially of 2,6-naphthalenedicarboxylic acid, ethylene glycol, and diethylene glycol components, the copolyester containing 1-5% by weight of the diethylene glycol component, based on the weight of the layer (B) copolyester, the layer (A) being provided with the layer (B) on one surface or both surfaces of the layer (A), wherein the laminated polyester film has a total thickness of 30 to 80 .mu.m and Young's moduli of at least 500 kg/mm.sup.2 in both the machine and transverse directions. ### Claim 10 (depends on 9) A magnetic recording disk according to claim 9, wherein layer (B) has a thickness of 0.2 to 10 .mu.m. ### Claim 11 (depends on 9) A magnetic recording disk according to claim 9, wherein the laminated polyester film has a Young's modulus in the machine direction of 550 to 610 and a Young's modulus in the transverse direction of 550 to 650 kg/mm.sup.2. ### Claim 12 (depends on 9) A magnetic recording disk according to claim 9, wherein the laminated polyester film has a bilayer structure formed of the layer (A) and the layer (B). ### Claim 13 (depends on 9) A magnetic recording disk according to claim 9, wherein the laminated polyester film has a three-layer structure formed of one layer (A) and two layers (B), the layer (A) forming a central layer. ### Claim 14 (depends on 9) A magnetic recording disk according to claim 9, wherein the magnetic layer comprises ferromagnetic particles in a vinyl acetate-vinyl chloride copolymer and polyurethane binder. ### Claim 15 A magnetic recording medium comprising of a magnetic recording layer and a biaxially oriented laminated polyester base film wherein the base film comprises a layer (A) of a polyester consisting essentially of 2,6-naphthalenedicarboxylic acid and ethylene glycol components and a layer (B) of a copolyester consisting essentially of 2,6-naphthalenedicarboxylic acid, ethylene glycol and diethylene glycol components, the copolyester containing 1 to 2.0% by weight of the diethylene glycol component, based on the weight of the layer (B) copolyester, the layer (A) being provided with the layer (B) on one surface or both surfaces of layer (A). ### Claim 16 A magnetic recording tape comprising of a magnetic recording layer and a biaxially oriented laminated polyester base film wherein the base film comprises a layer (A) of a polyester consisting essentially of 2,6-naphthalenedicarboxylic acid and ethylene glycol components and a layer (B) of a copolyester consisting essentially of 2,6-naphthalenedicarboxylic acid, ethylene glycol and diethylene glycol components, the copolyester containing 1 to 2.0% by weight of the diethylene glycol, based on the weight of the layer (B) copolyester, the layer (A) being provided with the layer (B) on one surface or both surfaces of layer (A), wherein the laminated polyester film has a total thickness of 3 to 12 .mu.m and Young's moduli of at least 500 kg/mm.sup.2 in both the machine and transverse directions. ### Claim 17 (depends on 16) A magnetic recording tape according to claim 16, wherein the laminated polyester film has a bilayer structure formed of the layer (A) and the layer (B). ### Claim 18 (depends on 16) A magnetic recording tape according to claim 16, wherein the laminated polyester film has a three-layer structure formed of one layer (A) and two layers (B), the layer (A) forming a central layer. ### Claim 19 (depends on 16) A biaxially oriented laminated film magnetic recording tape according to claim 16 wherein the magnetic layer comprises ferromagnetic particles in a vinyl acetate-vinyl chloride copolymer and polyurethane binder. ### Claim 20 A magnetic recording disk comprising of a magnetic recording layer and a biaxially oriented laminated polyester base film wherein the base film comprises a layer (A) of a polyester consisting essentially of 2,6-naphthalenedicarboxylic acid and ethylene glycol components and a layer (B) of a copolyester consisting essentially of 2,6-naphthalenedicarboxylic acid, ethylene glycol and diethylene glycol components, the copolyester containing 1 to 2.0% by weight of the diethylene glycol, based on the weight of the layer (B) copolyester, the layer (A) being provided with the layer (B) on one surface or both surfaces of layer (A), the layer (B) having the thickness of 0.2 to 5 .mu.m, wherein the laminated polyester film has a total thickness of 30 to 80 .mu.m and Young's moduli of at least 500 kg/mm.sup.2 in both the machine and transverse directions. ### Claim 21 (depends on 12) A magnetic recording disk according to claim 12, wherein the laminated polyester film has a bilayer structure formed of the layer (A) and the layer (B). ### Claim 22 (depends on 12) A magnetic recording disk according to claim 12, wherein the laminated polyester film has a three-layer structure formed of one layer (A) and two layers (B), the layer (A) forming a central layer. ### Claim 23 (depends on 20) A magnetic recording disk according to claim 20, wherein the magnetic layer comprises ferromagnetic particles in a vinyl acetate-vinyl chloride copolymer and polyurethane binder.