Patent US4561034A successfully refreshed from Google Patents.
US4561034A
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US
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Magnetic recording medium
Assignee: Maxell Ltd
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Filing: 1982-11-23
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Granted: 1985-12-24
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Expires: 2002-11-23
Abstract
Abstract A magnetic recording medium such as a magnetic tape, which comprises a base film, a magnetic layer having an elastic modulus at 1% elongation of not less than 1,200 kg/mm2 totally in both longitudinal and width directions which is higher than that of the base film, said magnetic layer being formed on one surface of the base film, and a backcoat layer having an elastic modulus at 1% elongation of not less than 1,200 kg/mm2 totally in both longitudinal and width directions which is higher than that of the base film, said backcoat layer being formed on another surface of the base film, said magnetic recording medium having a total thickness of not more than 17 mu , said magnetic recording medium having excellent mechanical strength and being used without buckle and injury during usage even in a thin thickness.
Inventors
- 👤 Naoto Akahane
- 👤 Yoshitake Yamaguchi
- 👤 Takeshi Matsuura
- 👤 Seiji Watatani
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 13:38
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/73; G11B5/735; Y; Y10; Y10S; Y10S428/00; Y10S428/90
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
113 words
A magnetic recording medium which comprises a base film, a magnetic layer having an elastic modulus at 1% elongation of not less than 1,200 kg/mm 2 totally in both longitudinal and width directions which is higher than that of the base film, said magnetic layer being formed on one surface of the base film, and a backcoat layer having an elastic modulus at 1% elongation of not less than 1,200 kg/mm 2 totally in both longitudinal and width directions which is higher than that of the base film, said backcoat layer being formed on another surface of the base film, said magnetic recording medium having a total thickness of not more than 17μ.
Claim 2
Dependent Claim
113 words
A magnetic recording medium which comprises a base film, a magnetic layer having an elastic modulus at 1% elongation of not less than 1,200 kg/mm 2 totally in both longitudinal and width directions which is higher than that of the base film, said magnetic layer being formed on one surface of the base film, and a backcoat layer having an elastic modulus at 1% elongation of not less than 1,200 kg/mm 2 totally in both longitudinal and width directions which is higher than that of the base film, said backcoat layer being formed on another surface of the base film, said magnetic recording medium having a total thickness of not more than 17μ.
Claim 3
Dependent Claim
46 words
A magnetic recording medium according to claim 1, wherein both of the magnetic layer and the backcoat layer have an elastic modulus at 1% elongation in total in both longitudinal and width directions of at least 100 kg/mm 2 higher than that of the base film.
Claim 4
Dependent Claim
46 words
A magnetic recording medium according to claim 2, wherein the magnetic layer has a total elastic modulus at 1% elongation of 1250 to 2400 kg/mm 2 , and the backcoat layer has a total elastic modulus at 1% elongation of 1300 to 3000 kg/mm 2 .
Claim 5
Dependent Claim
40 words
A magnetic recording medium according to claim 3, wherein the magnetic layer has a thickness of 0.1 to 0.6μ, the backcoat layer has a thickness of 0.1 to 6.0μ, and the base film has a thickness of 5 to 13μ.
Claim 6
Dependent Claim
101 words
A magnetic recording medium according to claim 2, wherein the magnetic layer has an elastic modulus at 1% elongation of 450 to 1200 kg/mm 2 in longitudinal direction and that of 450 to 1200 kg/mm 2 in width direction, and the backcoat layer has an elastic modulus at 1% elongation of 600 to 1500 kg/mm 2 in longitudinal direction and that of 600 to 1500 kg/mm 2 in width direction, and the base film has an elastic modulus at 1% elongation of 300 to 800 kg/mm 2 in longitudinal direction and that of 300 to 800 kg/mm 2 in width direction.
Claim 7
Dependent Claim
121 words
A magnetic recording medium according to claim 2, wherein the magnetic layer has an elastic modulus at 1% elongation of 450 to 1200 kg/mm 2 in longitudinal direction and that of 450 to 1200 kg/mm 2 in width direction and a thickness of 0.1 to 6.0μ, and the backcoat layer has an elastic modulus at 1% elongation of 600 to 1500 kg/mm 2 in longitudinal direction and that of 600 to 1500 kg/mm 2 in width direction and a thickness of 0.1 to 6.0μ, and the base film has an elastic modulus at 1% elongation of 300 to 800 kg/mm 2 in longitudinal and that of 300 to 800 kg/mm 2 in width direction and a thickness of 5 to 13μ.
Claim 8
Dependent Claim
25 words
A magnetic recording medium according to claim 1, wherein the magnetic layer and the backcoat layer both have a Mohs hardness of 4 to 6.
Claim 9
Dependent Claim
24 words
A magnetic recording medium according to claim 1, wherein the thickness of the magnetic recording medium is in the range of 6 to 17μ.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-12-23 | 1989-06-24 | 1989-12-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-12-23 | 1993-06-24 | 1993-12-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-12-23 | 1997-06-24 | 1997-12-24 | $7700.00 | Window Closed / Lapsed |