Patent US4886703A successfully refreshed from Google Patents.
US4886703A
Expired / Lapsed
US
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Magnetic recording medium
Assignee: Fujifilm Holdings Corp
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Filing: 1988-04-19
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Granted: 1989-12-12
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Expires: 2008-04-19
Abstract
Abstract A magnetic recording medium comprising a support having provided on one surface thereof a magnetic layer comprising a binder and ferromagnetic particles dispersed therein, and on the opposite surface thereof a backing layer comprising a binder and non-magnetic particles dispersed therein, wherein at least one of the binders comprises a vinyl chloride copolymer resin having a vinyl chloride unit content of about 70 wt % or more based on the total amount of the binder, a nitrogen content of about from 0.01 to 1 wt % based on the total amount of the binder, and a polymerization degree of about from 250 to 700; and the non-magnetic particles comprises fine carbon particles having a DBP oil absorption of about 150 ml/100 g or more.
Inventors
- 👤 Kazuo Hasumi
- 👤 Hideomi Watanabe
- 👤 Tsutomu Okita
- 👤 Katsumi Ryoke
- 👤 Hideaki Kosha
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 18:19
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/73; G11B5/735; G11B5/7356; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/25; Y10T428/256; Y10T428/257; Y10T428/26; Y10T428/263; Y10T428/264; Y10T428/265; Y10T428/30
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
175 words
A magnetic recording medium comprising a support having provided on one surface thereof a magnetic layer comprising a binder and ferromagnetic particles dispersed therein, and on the opposite surface thereof a backing layer comprising a binder and non-magnetic particles dispersed therein, wherein at least one of said binders comprises a vinyl chloride copolymer resin having a vinyl chloride unit content of about 70 wt. % or more based on the total amount of said binder, a nitrogen content of about from 0.01 to 1 wt. % based on the total amount of said binder, and a polymerization degree of about from 250 to 700; and said non-magnetic particles comprises fine carbon particles having a DBP oil absorption of about 150 ml/100 g or more, a particle diameter of from 1 to 500 mμ, and being selected from the group consisting of graphite, carbon black, and carbon black graphite polymer, wherein said vinyl chloride copolymer resin contains a heterocyclic group containing a nitrogen atom directly connected to the vinyl group of the vinyl chloride copolymer resin.
Claim 2
Dependent Claim
175 words
A magnetic recording medium comprising a support having provided on one surface thereof a magnetic layer comprising a binder and ferromagnetic particles dispersed therein, and on the opposite surface thereof a backing layer comprising a binder and non-magnetic particles dispersed therein, wherein at least one of said binders comprises a vinyl chloride copolymer resin having a vinyl chloride unit content of about 70 wt. % or more based on the total amount of said binder, a nitrogen content of about from 0.01 to 1 wt. % based on the total amount of said binder, and a polymerization degree of about from 250 to 700; and said non-magnetic particles comprises fine carbon particles having a DBP oil absorption of about 150 ml/100 g or more, a particle diameter of from 1 to 500 mμ, and being selected from the group consisting of graphite, carbon black, and carbon black graphite polymer, wherein said vinyl chloride copolymer resin contains a heterocyclic group containing a nitrogen atom directly connected to the vinyl group of the vinyl chloride copolymer resin.
Claim 3
Dependent Claim
35 words
A magnetic recording medium as claimed in claim 1, wherein said magnetic layer further comprises fine carbon particles in an amount of about 5 wt. % or less of the amount of said ferromagnetic particles.
Claim 4
Dependent Claim
37 words
A magnetic recording medium as claimed in claim 2, wherein said magnetic layer further comprises fine carbon particles in an amount of from 1 to 5 wt. % or less of the amount of said ferromagnetic particles.
Claim 5
Dependent Claim
26 words
A magnetic recording medium as claimed in claim 1, wherein said fine carbon particles have a DBP oil absorption of from 150 to 1,500 m/l100 g.
Claim 6
Dependent Claim
26 words
A magnetic recording medium as claimed in claim 4, wherein said fine carbon particles have a DBP oil absorption of from 150 to 400 ml/100 g.
Claim 7
Dependent Claim
41 words
A magnetic recording medium as claimed in claim 1, wherein said vinyl chloride copolymer resin comprises from 70 to 98 wt. % of vinyl chloride monomer units, and from about 0.01 to 1 wt. % of monomer units containing said amine.
Claim 8
Dependent Claim
25 words
A magnetic recording medium as claimed in claim 1, wherein said vinyl chloride copolymer resin has an average polymerization degree of from 250 to 700.
Claim 9
Dependent Claim
25 words
A magnetic recording medium as claimed in claim 7, wherein said vinyl chloride copolymer resin has an average polymerization degree of from 300 to 500.
Claim 10
Dependent Claim
96 words
A magnetic recording medium as claimed in claim 1, wherein said magnetic layer comprise from about 15 to 100 parts by weight of said vinyl chloride copolymer resin as a binder per 100 parts by weight of the total amount of said ferromagnetic particles and any non-magnetic carbon particles contained in said magnetic layer; and said backing layer comprises from about 15 to 100 parts by weight of said vinyl chloride copolymer resin as a binder per 100 parts by weight of said non-magnetic carbon particles and any other non-magnetic particles contained in said backing layer.
Claim 11
Dependent Claim
94 words
A magnetic recording medium as claimed in claim 9, wherein said magnetic layer comprises from 15 to 50 parts by weight of said vinyl chloride copolymer resin as a binder per 100 parts by weight of the total amount of said ferromagnetic particles and any non-magnetic carbon particles contained in said magnetic layer; and said backing layer comprises from 15 to 50 parts by weight of said vinyl chloride copolymer resin as a binder per 100 parts by weight of said non-magnetic carbon particles and any other non-magnetic particles contained in said backing layer.
Claim 12
Dependent Claim
94 words
A magnetic recording medium as claimed in claim 10, wherein said magnetic layer comprises from 18 to 35 parts by weight of said vinyl chloride copolymer resin as a binder per 100 parts by weight of the total amount of said ferromagnetic particles and any non-magnetic carbon particles contained in said magnetic layer; and said backing layer comprises from 18 to 35 parts by weight of said vinyl chloride copolymer resin as a binder per 100 parts by weight of said non-magnetic carbon particles and any other non-magnetic particles contained in said backing layer.
Claim 13
Dependent Claim
73 words
A magnetic recording medium as claimed in claim 1, wherein said binder comprises said vinyl chloride copolymer resin in an amount of from 10 to 60 wt. %, at least one of a urethane resin and an epoxy resins in an amount of from 10 to 90 wt. %, a polyisocyanate in an amount of from 5 to 40 wt. %, and a polyamide in an amount of 50 wt. % or less.
Claim 14
Dependent Claim
74 words
A magnetic recording medium as claimed in claim 12, wherein said binder comprises said vinyl chloride copolymer resin in an amount of from 30 to 60 wt. %, said at least one of a urethane resin and an epoxy resin in an amount of from 20 to 65 wt. %, said polyisocyanate in an amount of from 20 to 50 wt. %, and said polyamide in an amount of 30 wt. % or less.
Claim 15
Dependent Claim
23 words
A magnetic recording medium as claimed in claim 1, wherein said magnetic layer has a dry thickness of from 0.6 to 12.5 μm.
Claim 16
Dependent Claim
23 words
A magnetic recording medium as claimed in claim 1, wherein said backing layer has a dry thickness of from 0.3 to 2 μm.
Claim 17
Dependent Claim
34 words
A magnetic recording medium as claimed in claim 1, wherein said nitrogen is contained in an amine selected from the group consisting of aniline, o-toluidine, N-methylaniline, pyridine, α-picoline, β-picoline, γ-picoline, 2,4-lutidine, quinoline and morpholine.
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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) | 1992-12-11 | 1993-06-12 | 1993-12-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-12-11 | 1997-06-12 | 1997-12-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-12-11 | 2001-06-12 | 2001-12-12 | $7700.00 | Window Closed / Lapsed |