US4357391A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording medium
Assignee: TDK Corp
•
Filing: 1980-05-19
•
Granted: 1982-11-02
•
Expires: 2000-05-19
Abstract
Abstract A magnetic recording medium is provided which satisfies electromagnetic conversion characteristics and typical physical properties such as bonding strength, repeated-passage stability, still-playback characteristics, etc. without unfavorably affecting the surface smoothness. The binder in the magnetic coating contains in combination specific proportions of three components, a polyurethane resin, an epoxy resin, and a nitrocellulose whose protective ingredient has been replaced by a vinyl chloride-vinyl acetate copolymer is used as a resin binder in magnetic coating material together with a polyisocyanate curing agent.
Inventors
- 👤 Akihiko Hosaka
- 👤 Kiyotaka Okuyama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 18:26
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/702; G11B5/7021; G11B5/7022; C; C08; C08L; C08L75/00; C08L75/04; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31511; Y10T428/31551; Y10T428/31609
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
69 words
A magnetic recording medium comprising a magnetic coating material coated on a base material, said coating material comprising powdered magnetic material dispersed in a ternary binder composition containing from 30 to 70% by weight of a polyurethane resin, from 10 to 40% by weight of an epoxy resin and from 10 to 50% by weight of replaced nitrocellulose, containing vinyl chloride-vinyl acetate copolymer, together with a polyisocyanate curing agent.
Claim 2
Dependent Claim
69 words
A magnetic recording medium comprising a magnetic coating material coated on a base material, said coating material comprising powdered magnetic material dispersed in a ternary binder composition containing from 30 to 70% by weight of a polyurethane resin, from 10 to 40% by weight of an epoxy resin and from 10 to 50% by weight of replaced nitrocellulose, containing vinyl chloride-vinyl acetate copolymer, together with a polyisocyanate curing agent.
Claim 3
Dependent Claim
26 words
A magnetic recording medium of claim 1 in which the amount of vinyl chloride-vinyl acetate copolymer is 30% by weight based on the weight of nitrocellulose.
Claim 4
Dependent Claim
17 words
A magnetic recording medium of claim 1 containing from 5 to 20 parts by weight of polyisocyanate.
Claim 5
Dependent Claim
32 words
A magnetic recording medium of claim 1 wherein the binder contains 40% by weight of a polyurethane resin, 40% by weight of an epoxy resin and 20% by weight of replaced nitrocellulose.
Claim 6
Dependent Claim
33 words
A magnetic recording medium of claim 1 wherein the binder contains 55% by weight of a polyurethane resin, 30% by weight of an epoxy resin and 15% by weight of a replaced nitrocellulose.
Claim 7
Dependent Claim
33 words
A magnetic recording medium of claim 1 wherein the binder contains 60% by weight of a polyurethane resin, 10% by weight of an epoxy resin and 30% by weight of a replaced nitrocellulose.
Claim 8
Dependent Claim
18 words
A magnetic recording medium according to any one of claims 1-6 which is a video recording magnetic tape.
References Cited (Backward Citations)
US3320090A
Cited
US3740266A
Cited
US3597273A
Cited
US3840400A
Cited
US3810840A
Cited
US3911196A
Cited
JPS5144903A
Cited
US4115290A
Cited
SU650099A1
Cited
JPS541004A
Cited
JPS5429085A
Cited
US4186228A
Cited
US4238548A
Cited
US4323628A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-11-01 | 1986-05-03 | 1986-11-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-11-01 | 1990-05-03 | 1990-11-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-11-01 | 1994-05-03 | 1994-11-02 | $7700.00 | Window Closed / Lapsed |