US4410565A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making a magnetic recording medium
Assignee: Fujifilm Holdings Corp
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Filing: 1982-02-25
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Granted: 1983-10-18
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Expires: 2002-02-25
Abstract
Abstract A magnetic recording medium comprising a substrate, a thermoplastic prime coat provided thereon, and a ferromagnetic metal layer having columnar grains which at least partially penetrate into the prime coat from the top thereof and are integrated therewith. The medium is prepared by applying a prime coat onto a substrate, forming a magnetic metal layer having columnar grains by vapor deposition, and then heating and pressing the obtained combination.
Inventors
- 👤 Tatsuji Kitamoto
- 👤 Ryuji Shirahata
- 👤 Yasuo Tamai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 16:04
CPC Classifications
H; H01; H01F; H01F41/00; H01F41/14; H01F41/20; G; G11; G11B; G11B5/00; G11B5/62; G11B5/64; G11B5/84; G11B5/851
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
61 words
A method of preparing a magnetic recording medium which comprises applying a thermoplastic prime-coating layer onto a substrate, forming a ferromagnetic metal layer having columnar grain structures on said prime-coating layer by means of vapor deposition, and thereafter pressing said ferromagnetic metal layer from the top thereof, whereby said prime-coating layer is at least partially integrated with said ferromagnetic metal layer.
Claim 2
Independent Claim
61 words
A method of preparing a magnetic recording medium which comprises applying a thermoplastic prime-coating layer onto a substrate, forming a ferromagnetic metal layer having columnar grain structures on said prime-coating layer by means of vapor deposition, and thereafter pressing said ferromagnetic metal layer from the top thereof, whereby said prime-coating layer is at least partially integrated with said ferromagnetic metal layer.
Claim 3
Dependent Claim
25 words
A method of preparing a magnetic recording medium as defined in claim 1 wherein said vapor deposition is effected by the oblique incidence deposition process.
Claim 4
Dependent Claim
60 words
A method of preparing a magnetic recording medium as defined in claim 2 wherein the vapor stream of the ferromagnetic metal is caused to impinge upon the prime-coating layer at a large incident angle and be deposited thereon at a low deposition rate, followed by a gradual decrease in the incident angle and a gradual increase in the deposition rate.
Claim 5
Dependent Claim
40 words
A method of preparing a magnetic recording medium as defined in claim 2 wherein said oblique incidence deposition is effected at an incident angle of the vapor stream of 50° or more with respect to the surface of the substrate.
Claim 6
Dependent Claim
35 words
A method of preparing a magnetic recording medium as defined in claim 4 wherein said pressing is conducted by use of calender rolls comprising at least one metal roll and at least one elastic roll.
Claim 7
Dependent Claim
36 words
A method of preparing a magnetic recording medium as defined in claim 5 wherein the surface of the magnetic layer is brought into contact with the metal roll, and the non-magnetic surface with the elastic roll.
Claim 8
Dependent Claim
33 words
A method of preparing a magnetic recording medium as defined in claim 5 wherein said metal roll is heated to a temperature not less than the softening point of the thermoplastic prime-coating layer.
Claim 9
Dependent Claim
31 words
A method of preparing a magnetic recording medium as defined in claim 5 wherein a linear pressure ranging from 10 to 200 kg/cm is applied between the metal and elastic rolls.
Claim 10
Dependent Claim
25 words
A method of preparing a magnetic recording medium as defined in claim 5 wherein said elastic roll has a Shore hardness of 75 or more.
Claim 11
Dependent Claim
50 words
A method of preparing a magnetic recording medium as defined in claim 1 wherein said prime-coating layer is made of a thermoplastic resin having a softening point of 150° C. or less, an average molecular weight of 10,000 to 200,000, and a degree of polymerization of about 200 to 2,000.
Claim 12
Dependent Claim
29 words
A method of preparing a magnetic recording medium as defined in claim 1 wherein said prime-coating layer has a thickness of about 0.03 to 2.0μ in the dry state.
Claim 13
Dependent Claim
34 words
A method of preparing a magnetic recording medium as defined in claim 1 wherein said prime-coating layer contains a lubricant in the amount of 10 wt. % or less based on the prime-coating layer.
Claim 14
Dependent Claim
25 words
A method of preparing a magnetic recording medium as defined in claim 1 wherein said ferromagnetic metal layer has a thickness of 0.05 to 2μ.
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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) | 1986-10-17 | 1987-04-18 | 1987-10-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-10-17 | 1991-04-18 | 1991-10-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-10-17 | 1995-04-18 | 1995-10-18 | $7700.00 | Window Closed / Lapsed |