Patent US4431700A successfully refreshed from Google Patents.
US4431700A
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US
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Magnetic recording medium
Assignee: Fujifilm Holdings Corp
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Filing: 1982-12-20
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Granted: 1984-02-14
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Expires: 2002-12-20
Abstract
Abstract The present invention relates to a magnetic recording medium excellent in S/N ratio and abrasion resistance, which comprises a non-magnetic support and a magnetic recording layer coated thereon, consisting of a ferromagnetic fine powder and a binder, in which the binder contains (1) nitrocellulose having an average polymerization degree of 50 to 300 and a nitrification degree of 10.7 to 13 and (2) a polyurethane resin having a number average molecular weight of 40,000 to 100,000, obtained from diphenylmethane diisocyanate and a mixture of polyneopentyl adipate having an average molecular weight of 800 to 2000 and polybutylene adipate having an average molecular weight of 800 to 2000 in a mixing proportion by weight of 2/8 to 9/1.
Inventors
- 👤 Yasuyuki Yamada
- 👤 Nobuo Tsuji
- 👤 Yasuyuki Tanaka
- 👤 Koichi Yamauchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 11:38
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/702; G11B5/7021; G11B5/7022; C; C08; C08G; C08G18/00; C08G18/06; C08G18/28; C08G18/40; C08G18/42; C08G18/4202; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/26; Y10T428/263; Y10T428/264; Y10T428/265; Y10T428/31504; Y10T428/31551; Y10T428/31609; Y10T428/31678; Y10T428/31721; Y10T428/31725; Y10T428/31765; Y10T428/31786; Y10T428/3179; Y10T428/31971
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
104 words
A magnetic recording medium comprising a non-magnetic support and a magnetic recording layer coated thereon, consisting of a ferromagnetic fine powder and a binder, in which the binder contains (1) nitrocellulose having an average polymerization degree of 50 to 300 and a nitrification degree of 10.7 to 13 and (2) a polyurethane resin having a number average molecular weight of 40,000 to 100,000, obtained from diphenylmethane diisocyanate and a mixture of polyneopentyl adipate having an average molecular weight of 800 to 2000 and polybutylene adipate having an average molecular weight of 800 to 2000 in a mixing proportion by weight of 2/8 to 9/1.
Claim 2
Dependent Claim
104 words
A magnetic recording medium comprising a non-magnetic support and a magnetic recording layer coated thereon, consisting of a ferromagnetic fine powder and a binder, in which the binder contains (1) nitrocellulose having an average polymerization degree of 50 to 300 and a nitrification degree of 10.7 to 13 and (2) a polyurethane resin having a number average molecular weight of 40,000 to 100,000, obtained from diphenylmethane diisocyanate and a mixture of polyneopentyl adipate having an average molecular weight of 800 to 2000 and polybutylene adipate having an average molecular weight of 800 to 2000 in a mixing proportion by weight of 2/8 to 9/1.
Claim 3
Dependent Claim
17 words
The magnetic recording medium of claim 1, wherein the binder further contains a low molecular weight polyisocyanate.
Claim 4
Dependent Claim
26 words
The magnetic recording medium of claim 2, wherein the low molecular weight polyisocyanate is in a proportion by weight of 5 to 40% to the binder.
Claim 5
Dependent Claim
41 words
The magnetic recording medium of claim 2, wherein the low molecular weight polyisocyanate is selected from the group consisting of aliphatic, alicyclic and aromatic di-, tri- and tetraisocyanates, dimers and trimers thereof and addition products thereof with dihydric or trihydric alcohols.
Claim 6
Dependent Claim
21 words
The magnetic recording medium of claim 1, wherein the binder further contains a solvent, dispersing agent, lubricant, abrasives and antistatic agent.
Claim 7
Dependent Claim
36 words
The magnetic recording medium of claim 1, wherein the non-magnetic support is of polyethylene terephthalate, polyethylene-2,6-naphthalate, polyethylene, polypropylene, cellulose triacetate, cellulose diacetate, cellulose acetate butyrate, cellulose acetate propionate, polyvinyl chloride, polyvinylidene chloride, polycarbonate, polyimide or polyamideimide.
Claim 8
Dependent Claim
90 words
The magnetic recording medium of claim 1, wherein the ferromagnetic fine powder is selected from the group consisting of powders of γ-Fe 2 O 3 , Co-doped γ-Fe 2 O 3 , Fe 3 O 4 , Co-doped Fe 3 O 4 , Berthollide compounds of γ-Fe 2 O 3 and Fe 3 O 4 (FeOx: 1.33<x<1.50), Co-doped Berthollide compounds of γ-Fe 2 O 3 and Fe 3 O 4 (FeOx: 1.33<x<1.50), CrO 2 , Co-Ni-P alloys, Co-Ni-Fe alloys, Co-B-Ni-Fe alloys, Fe-Ni-Zn alloys, Fe-Mn-Zn alloys, Fe-Co-Ni-P alloys and Ni-Co alloys.
Claim 9
Dependent Claim
38 words
The magnetic recording medium of claim 7, wherein the ferromagnetic iron oxide further contains 0 to 10 atom % of at least one divalent metal selected from the group consisting of Cr, Mn, Co, Ni, Cu and Zn.
Claim 10
Dependent Claim
51 words
The magnetic recording medium of claim 7, wherein the ferromagnetic chromium dioxide further contains 0 to 20 % by weight of at least one element selected from the group consisting of Na, K, Ti, V, Mn, Fe, Co, Ni, Te, Ru, Sn, Ce, Pb, P, Sb and Te and oxides thereof.
Claim 11
Dependent Claim
27 words
The magnetic recording medium of claim 1, wherein the binder is in a proportion by weight of 13 to 50 to 100 of the ferromagnetic fine powder.
Claim 12
Dependent Claim
21 words
The magnetic recording medium of claim 1, wherein the nitrocellulose and polyurethane resin are in a proportion by weight of 100:130-20.
Claim 13
Dependent Claim
23 words
The magnetic recording medium of claim 1, wherein the magnetic recording layer has a thickness of 1 to 18 μm on dry basis.
Claim 14
Dependent Claim
21 words
The magnetic recording medium of claim 1, wherein the surface of the magnetic recording medium is finished by a supercalendering treatment.
Claim 15
Dependent Claim
42 words
The magnetic recording medium of claim 13, wherein the supercalendering treatment is carried out with a linear nip pressure of rolls of 80 to 300 Kg/cm, tape transporting speed of 30 to 200 m/min and roll temperature of 25° to 120° C.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-02-13 | 1987-08-15 | 1988-02-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-02-13 | 1991-08-15 | 1992-02-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-02-13 | 1995-08-15 | 1996-02-14 | $7700.00 | Window Closed / Lapsed |