US4699847A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording medium
Assignee: TDK Corp
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Filing: 1985-07-24
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Granted: 1987-10-13
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Expires: 2005-07-24
Abstract
Abstract In a magnetic recording medium comprising a plastic base film and a magnetic layer, the base film is plasma treated at frequencies in the range of 10 kHz to 200 kHz in an inorganic gas containing at least 5% of oxygen. The magnetic layer is formed on the plasma treated base film by applying a magnetic composition of ferromagnetic fine particles dispersed in a plasticized binder compound comprising a radiation-sensitive modified resin in admixture with a radiation-sensitive modified flexible resin or prepolymer, oligomer or telomer thereof, and exposing the composition to radiation for crosslinking and polymerization.
Inventors
- 👤 Masatoshi Nakayama
- 👤 Haruyuki Morita
- 👤 Yuichi Kubota
- 👤 Keiko Tsuchiya
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 12:28
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/702; G11B5/7023; G11B5/7026; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31786; Y10T428/31797; Y10T428/31855; Y10T428/31935
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
72 words
A magnetic recording medium comprising a base film which has been plasma treated at a frequency in the range of 10 to 200 kilohertz, and a magnetic layer formed thereon from a magnetic composition comprising ferromagnetic fine particles and a plasticized binder compound comprising a radiation-sensitive modified resin in admixture with a radiation-sensitive modified flexible resin or prepolymer, oligomer or telomer thereof, said composition being crosslinked and polymerized by exposure to radiation.
Claim 2
Dependent Claim
72 words
A magnetic recording medium comprising a base film which has been plasma treated at a frequency in the range of 10 to 200 kilohertz, and a magnetic layer formed thereon from a magnetic composition comprising ferromagnetic fine particles and a plasticized binder compound comprising a radiation-sensitive modified resin in admixture with a radiation-sensitive modified flexible resin or prepolymer, oligomer or telomer thereof, said composition being crosslinked and polymerized by exposure to radiation.
Claim 3
Dependent Claim
35 words
A magnetic recording medium according to claim 1 wherein the base film is plasma treated at a frequency in the range of 10 to 200 kilohertz in an atmosphere comprising an inorganic gas containing oxygen.
Claim 4
Dependent Claim
20 words
A magnetic recording medium according to claim 2 wherein the inorganic gas contains 5 to 100% by volume of oxygen.
Claim 5
Dependent Claim
23 words
A magnetic recording medium according to claim 3 which further comprises an undercoat layer formed between the base film and the magnetic layer.
Claim 6
Dependent Claim
29 words
A magnetic recording medium according to claim 1 wherein the radiation-sensitive modified resin has at least one radiation-sensitive unsaturated double bond selected from acrylic, maleic and allylic double bonds.
Claim 7
Dependent Claim
36 words
A magnetic recording medium according to claim 1 wherein the radiation-sensitive modified flexible resin or prepolymer, oligomer or telomer thereof has at least one radiation-sensitive unsaturated double bond selected from acrylic, maleic and allylic double bonds.
Claim 8
Dependent Claim
49 words
The magnetic recording medium according to claim 1 wherein the radiation-sensitive modified flexible resin or prepolymer, oligomer or telomer thereof has a dynamic modulus of lower than 1×10 9 dyn/cm 2 as measured in a temperature range from 20° C. to 60° C. at a frequency of 100 Hz.
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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) | 1990-10-12 | 1991-04-13 | 1991-10-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-10-12 | 1995-04-13 | 1995-10-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-10-12 | 1999-04-13 | 1999-10-13 | $7700.00 | Window Closed / Lapsed |