US4539257A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording medium having improved running properties
Assignee: Fujifilm Holdings Corp
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Filing: 1984-04-13
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Granted: 1985-09-03
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Expires: 2004-04-13
Abstract
Abstract A magnetic recording medium comprised of a nonmagnetic support base having a magnetic layer provided thereon is disclosed. The magnetic layer includes ferromagnetic particles dispersed in a binder in combination with carbon black particles. The carbon black particles have an average primary particle size in the range of 30 mμ to 50 mμ. Further, the carbon black is capable of the adsorption of 120 ml or more of dibutyl phthalate per 100 g of carbon black. By utilizing the particular carbon black of the present invention it is possible to obtain a magnetic recording medium having improved running properties.
Inventors
- 👤 Katsumi Ryoke
- 👤 Kenichi Masuyama
- 👤 Takashi Yoneyama
- 👤 Norio Nasu
- 👤 Eiichi Tadokoro
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 12:36
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; Y10T428/25; Y10T428/26; Y10T428/263; Y10T428/264; Y10T428/265
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
64 words
A magnetic recording medium, comprising: a non-magnetic support base having provided thereon; a magnetic layer comprised of ferromagnetic particles dispersed in a binder along with carbon black particles having an average primary particle size in the range 30 mμ to 50 mμ, the carbon black being capable of the adsorption of 120 ml or more of dibutyl phthalate per 100 g of carbon black.
Claim 2
Dependent Claim
64 words
A magnetic recording medium, comprising: a non-magnetic support base having provided thereon; a magnetic layer comprised of ferromagnetic particles dispersed in a binder along with carbon black particles having an average primary particle size in the range 30 mμ to 50 mμ, the carbon black being capable of the adsorption of 120 ml or more of dibutyl phthalate per 100 g of carbon black.
Claim 3
Dependent Claim
29 words
A magnetic recording medium as claimed in claim 1, wherein the carbon black is capable of the adsorption of 120 to 150 ml per 100 g of carbon black.
Claim 4
Dependent Claim
25 words
A magnetic recording medium as claimed in claim 1, wherein the carbon black has a specific surface area of 35 m 2 /g or more.
Claim 5
Dependent Claim
25 words
A magnetic recording medium as claimed in claim 3, wherein the carbon black has a specific surface area of 40 to 60 m 2 /g.
Claim 6
Dependent Claim
46 words
A magnetic recording medium as claimed in claim 1, wherein the ferromagnetic particles are selected from the group consisting of γ-Fe 2 O 3 , Fe 3 O 4 , γ-FeOx (1.33<x<1.50), CrO 2 , Co--Ni--P alloy, Co--Ni--Fe--B alloy, Fe--Ni--Zn alloy, Ni--Co alloy and Co--Ni--Fe alloy.
Claim 7
Dependent Claim
34 words
A magnetic recording medium as claimed in claim 1, wherein the carbon black is present in an amunt of 0.1 to 30 parts by weight per 100 parts by weight of the ferromagnetic particles.
Claim 8
Dependent Claim
40 words
A magnetic recording medium as claimed in claim 1, wherein the binder is selected from the group consisting of nitrocellulose, polyurethane, vinyl chloride-vinyl acetate-vinyl alcohol copolymers, vinyl chloride-vinyl acetate-maleic acid copolymers, vinyl chloride-vinyl acetate-maleic acid-vinyl alcohol copolymers and epoxy resins.
Claim 9
Dependent Claim
33 words
A magnetic recording medium as claimed in claim 7, wherein the binder is present in an amount of 10 to 200 parts by weight per 100 parts by weight of the ferromagnetic particles.
Claim 10
Dependent Claim
35 words
A magnetic recording medium as claimed in claim 1, further comprising a lubricant present in an amount in the range of 0.2 to 20 parts by weight per 100 parts by weight of the binder.
Claim 11
Dependent Claim
28 words
A magnetic recording medium as claimed in claim 9, wherein the lubricant is selected from the group consisting of dimethyl polysiloxane, butyl stearate, butyl palmitate and isooctyl stearate.
Claim 12
Dependent Claim
35 words
A magnetic recording medium as claimed in claim 9, further comprising a dispersing agent in an amount in the range of 1 to 20 parts by weight per 100 parts by weight of the binder.
Claim 13
Dependent Claim
47 words
A magnetic recording medium as claimed in claim 11, further comprising an abrasive having an average particle size in the range of 0.05 to 5 μm in an amount in the range of 0.5 to 20 parts by weight per 100 parts by weight of the binder.
Claim 14
Dependent Claim
24 words
A magnetic recording medium as claimed in claim 1, wherein the magnetic layer has a thickness in the range of 1 to 20 μm.
Claim 15
Dependent Claim
16 words
A magnetic recording medium as claimed in claim 1, wherein said binder is a resin binder.
Claim 16
Dependent Claim
24 words
A magnetic recording medium as claimed in claim 14, wherein the average primary particle size of said carbon black is 30 to 45 mμ.
Claim 17
Dependent Claim
32 words
A magnetic recording medium as claimed in claim 15, wherein the amount of dibutyl phthalate adsorption of said carbon black is 125 to 131 ml based on 100 g of carbon black.
Claim 18
Dependent Claim
25 words
A magnetic recording medium as claimed in claim 16, wherein said carbon black has a specific surface area of 43 to 56 m 2 /g.
Claim 19
Dependent Claim
31 words
A magnetic recording medium as claimed in claim 17, wherein the amount of carbon black is 1 to 20 parts by weight based on 100 parts by weight of ferromagnetic particles.
Claim 20
Dependent Claim
31 words
A magnetic recording medium as claimed in claim 18, wherein the amount of carbon black is 2 to 10 parts by weight based on 100 parts by weight of ferromagnetic particles.
Claim 21
Dependent Claim
31 words
A magnetic recording medium as claimed in claim 19, wherein from 30 to 150 parts by weight of resin binder is used based on 100 parts by weight of ferromagnetic particles.
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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) | 1988-09-02 | 1989-03-04 | 1989-09-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-09-02 | 1993-03-04 | 1993-09-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-09-02 | 1997-03-04 | 1997-09-03 | $7700.00 | Window Closed / Lapsed |