US4032682A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording element and method for making same
Assignee: Eastman Kodak Co
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Filing: 1975-07-17
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Granted: 1977-06-28
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Expires: 1995-07-17
Abstract
Abstract An element for magnetic recording is comprised of a substrate or support coated on one of its surfaces with one or more magnetic layers comprising a dispersion of magnetizable particles in a binder. At least one of these magnetic layers has a porous structure formed by precipitation of at least part of the binder in the form of fine particles, with air included between said particles. Flexible magnetic tapes having such porous coatings are practically free from transverse incurvature, and have an excellent aptitude for calendering.
Inventors
- 👤 Claude Jeanine Masson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:03
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/708; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/249921; Y10T428/249953; Y10T428/249986; Y10T428/31504; Y10T428/31786; Y10T428/31855; Y10T428/31931; Y10T428/31938
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
156 words
A magnetic recording element comprising a support coated on one of its surfaces with at least one magnetic layer comprised of a dispersion of magnetizable particles in resinous binder, said binder comprising a single copolymer of vinyl acetate and vinyl chloride, or a mixture of copolymers of vinyl acetate and vinyl chloride of different compositions, or a mixture of a copolymer of vinyl acetate and vinyl chloride with polyvinyl butyral, or a mixture of polyvinylidene chloride-acrylonitrile copolymer with a copolymer of vinyl acetate and vinyl chloride, or at least one cellulose acetobutyrate composition, or a mixture of a copolymer of vinyl acetate and vinyl chloride with a copolymer of vinyl chloride and methyl acrylate; said at least one magnetic layer having a porous structure and comprising fine particles of said binder with interstices included between particles; and said element exhibiting a transverse incurvature of not more than 4 mm across a 35 mm wide strip thereof.
Claim 2
Dependent Claim
156 words
A magnetic recording element comprising a support coated on one of its surfaces with at least one magnetic layer comprised of a dispersion of magnetizable particles in resinous binder, said binder comprising a single copolymer of vinyl acetate and vinyl chloride, or a mixture of copolymers of vinyl acetate and vinyl chloride of different compositions, or a mixture of a copolymer of vinyl acetate and vinyl chloride with polyvinyl butyral, or a mixture of polyvinylidene chloride-acrylonitrile copolymer with a copolymer of vinyl acetate and vinyl chloride, or at least one cellulose acetobutyrate composition, or a mixture of a copolymer of vinyl acetate and vinyl chloride with a copolymer of vinyl chloride and methyl acrylate; said at least one magnetic layer having a porous structure and comprising fine particles of said binder with interstices included between particles; and said element exhibiting a transverse incurvature of not more than 4 mm across a 35 mm wide strip thereof.
Claim 3
Dependent Claim
15 words
A magnetic recording element according to claim 1 wherein said support is a flexible tape.
Claim 4
Independent Claim
115 words
A method for making a magnetic recording element comprising: preparing a dispersion of magnetizable particles in a solution of resinous binder consisting essentially of at least one copolymer of vinyl acetate and vinyl chloride, or at least one cellulose acetobutyrate composition, or a mixture of a copolymer of vinyl acetate and vinyl chloride with either polyvinyl butyral or with a copolymer of vinylidene chloride and acrylonitrile or with a copolymer of vinyl chloride and methyl acrylate, dissolved in a solvent system comprising butanol and either methylene chloride, acetone, or methyl ethyl ketone; coating said dispersion on a substrate; and causing said solvents to evaporate, leaving a magnetic layer having a porous structure on said substrate.
Claim 5
Independent Claim
115 words
A method for making a magnetic recording element comprising: preparing a dispersion of magnetizable particles in a solution of resinous binder consisting essentially of at least one copolymer of vinyl acetate and vinyl chloride, or at least one cellulose acetobutyrate composition, or a mixture of a copolymer of vinyl acetate and vinyl chloride with either polyvinyl butyral or with a copolymer of vinylidene chloride and acrylonitrile or with a copolymer of vinyl chloride and methyl acrylate, dissolved in a solvent system comprising butanol and either methylene chloride, acetone, or methyl ethyl ketone; coating said dispersion on a substrate; and causing said solvents to evaporate, leaving a magnetic layer having a porous structure on said substrate.
Claim 6
Dependent Claim
27 words
A method in accordance with claim 3 wherein said substrate is a flexible tape, and wherein the resulting magnetic recording element is practically free from transverse incurvature.
Claim 7
Dependent Claim
13 words
A method in accordance with claim 3, also comprising calendering said magnetic layer.
Claim 8
Dependent Claim
26 words
A method in accordance with claim 3 wherein said resinous binder is a mixture of a copolymer of vinyl acetate and vinyl chloride with polyvinyl butyral.
Claim 9
Dependent Claim
26 words
A method in accordance with claim 3 wherein said resinous binder is a mixture of two different cellulose acetobutyrates, and said solvent comprises acetone and butanol.
Claim 10
Dependent Claim
41 words
A method in accordance with claim 3 wherein said resinous binder is a mixture of a copolymer of vinylidene chloride and acrylonitrile with a copolymer of vinyl acetate and vinyl chloride, and wherein said solvent comprises butanol and methyl ethyl ketone.
Claim 11
Dependent Claim
32 words
A method in accordance with claim 3 wherein said resinous binder is at least one copolymer of vinyl acetate and vinyl chloride, and wherein said solvent system comprises butanol and methylene chloride.
Claim 12
Dependent Claim
21 words
A method in accordance with claim 9 wherein said resinous binder is only one copolymer of vinyl acetate and vinyl chloride.
Claim 13
Dependent Claim
21 words
A method in accordance with claim 9 wherein said resinous binder is two different copolymers of vinyl acetate and vinyl chloride.
Claim 14
Independent Claim
133 words
A method for making a magnetic recording element comprising: preparing a dispersion of magnetic particles in a resinous binder-solvent system selected from the group consisting of: (a) at least one copolymer of vinyl acetate and vinyl chloride dissolved in a mixture of butanol and methylene chloride, (b) polyvinyl butyral and a copolymer of vinyl acetate and vinyl chloride dissolved in a mixture of butanol and methylene chloride, (c) cellulose acetobutyrate dissolved in a mixture of butanol and acetone, and (d) a copolymer of vinylidene chloride and acrylonitrile, and a copolymer of vinyl acetate and vinyl chloride, dissolved in a mixture of butanol and methyl ethyl ketone; coating said dispersion on a substrate; causing said solvents to evaporate, leaving a magnetic layer having a porous structure on said substrate; and calendering said magnetic layer.
Claim 15
Independent Claim
133 words
A method for making a magnetic recording element comprising: preparing a dispersion of magnetic particles in a resinous binder-solvent system selected from the group consisting of: (a) at least one copolymer of vinyl acetate and vinyl chloride dissolved in a mixture of butanol and methylene chloride, (b) polyvinyl butyral and a copolymer of vinyl acetate and vinyl chloride dissolved in a mixture of butanol and methylene chloride, (c) cellulose acetobutyrate dissolved in a mixture of butanol and acetone, and (d) a copolymer of vinylidene chloride and acrylonitrile, and a copolymer of vinyl acetate and vinyl chloride, dissolved in a mixture of butanol and methyl ethyl ketone; coating said dispersion on a substrate; causing said solvents to evaporate, leaving a magnetic layer having a porous structure on said substrate; and calendering said magnetic layer.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-06-27 | 1980-12-27 | 1981-06-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-06-27 | 1984-12-27 | 1985-06-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-06-27 | 1988-12-27 | 1989-06-28 | $7700.00 | Window Closed / Lapsed |