US4649072A
Expired / Lapsed
US
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Magnetic recording medium
Assignee: Fujifilm Holdings Corp
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Filing: 1985-09-23
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Granted: 1987-03-10
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Expires: 2005-09-23
Abstract
Abstract A magnetic recording medium comprising a non-magnetic support having provided thereon a magnetic layer on one side and a backing layer on the other side, wherein the backing layer contains (1) non-magnetic powders containing carbon black having an average particle diameter of from 0.1 to 1 μm; (2) two or more binders wherein (a) at least one of the binders is a resin having a 100% modulus of from 15 to 150 kg/cm 2 in an amount of from 50 to 95 wt % based on the total amount of the binders in the backing layer, and (b) the rest binder(s) is/are a resin other than the resin having a 100% modulus of from 15 to 150 kg/cm 2 , and the weight ratio of all the non-magnetic powders to all the binders in the backing layer is from 300:100 to 40:100; and (3) a polyisocyanate in an amount of from 15 to 40 wt % based on the total amount of the binders in the backing layer.
Inventors
- 👤 Katsumi Ryoke
- 👤 Nobutaka Yamaguchi
- 👤 Masatoshi Takahashi
- 👤 Kazuko Hanai
- 👤 Hideaki Kosha
- 👤 Eiichi Tadokoro
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 03:32
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; Y10T428/24; Y10T428/24942; Y10T428/25; Y10T428/30; Y10T428/31504; Y10T428/31551
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
179 words
A magnetic recording medium comprising a non-magnetic support having provided thereon a magnetic layer on one side and a backing layer on the other side, wherein the backing layer contains (1) non-magnetic powders containing carbon black having an average particle diameter of from 0.15 to 1.0 μm; (2) two or more binders wherein (a) at least one of the binders is a resin having a 100% modulus of from 15 to 150 kg/cm 2 in an amount of from 50 to 95 wt% based on the total amount of the binders in the backing layer, and (b) the remaining binder is, or if more than one remaining binder is present, the remaining binders are a resin other than the resin having a 100% modulus of from 15 to 150 kg/cm 2 , and the weight ratio of all the non-magnetic powders to all the binders in the backing layer is from 300:100 to 40:100; and (3) a polyisocyanate in an amount of from 15 to 40 wt% based on the total amount of the binders in the backing layer.
Claim 2
Dependent Claim
179 words
A magnetic recording medium comprising a non-magnetic support having provided thereon a magnetic layer on one side and a backing layer on the other side, wherein the backing layer contains (1) non-magnetic powders containing carbon black having an average particle diameter of from 0.15 to 1.0 μm; (2) two or more binders wherein (a) at least one of the binders is a resin having a 100% modulus of from 15 to 150 kg/cm 2 in an amount of from 50 to 95 wt% based on the total amount of the binders in the backing layer, and (b) the remaining binder is, or if more than one remaining binder is present, the remaining binders are a resin other than the resin having a 100% modulus of from 15 to 150 kg/cm 2 , and the weight ratio of all the non-magnetic powders to all the binders in the backing layer is from 300:100 to 40:100; and (3) a polyisocyanate in an amount of from 15 to 40 wt% based on the total amount of the binders in the backing layer.
Claim 3
Dependent Claim
45 words
The magnetic recording medium as claimed in claim 1, wherein the amount of the carbon black having an average particle diameter of from 0.15 to 1.0 μm is at least 50 wt% based on the total amount of the non-magnetic powders in the backing layer.
Claim 4
Dependent Claim
27 words
The magnetic recording medium as claimed in claim 1, wherein the resin having a 100% modulus of from 15 to 150 kg/cm 2 is a polyurethane resin.
Claim 5
Dependent Claim
33 words
The magnetic recording medium as claimed in claim 1, wherein the amount of the polyisocyanate is in the range of from 15 to 30 wt% based on the total amount of the binders.
Claim 6
Dependent Claim
44 words
The magnetic recording medium as claimed in claim 1, wherein the magnetic layer contains ferromagnetic fine powder having a specific surface area of from 25 to 70 m 2 /g and the dry thickness of the backing layer is from 1.5 to 2.5 μm.
Claim 7
Dependent Claim
27 words
The magnetic recording medium as claimed in claim 5, wherein the ferromagnetic fine powder has a specific surface area of from 27 to 70 m 2 /g.
Claim 8
Dependent Claim
27 words
The magnetic recording medium as claimed in claim 6, wherein the ferromagnetic fine powder has a specific surface area of from 30 to 70 m 2 /g.
Claim 9
Dependent Claim
27 words
The magnetic recording medium as claimed in claim 1, wherein the color transmittance in benzene of the carbon black in the backing layer is at least 50%.
Claim 10
Dependent Claim
25 words
The magnetic recording medium as claimed in claim 1, wherein the carbon black has a specific surface area of 25 m 2 /g or less.
Claim 11
Dependent Claim
24 words
The magnetic recording medium as claimed in claim 1, wherein the carbon black has an average particle diameter of from 0.15 to 0.5 μm.
Claim 12
Dependent Claim
30 words
The magnetic recording medium as claimed in claim 1, wherein the resin of binder (2)(a) is a resin having a 100% modulus of from 15 to 120 kg/cm 2 .
Claim 13
Dependent Claim
46 words
The magnetic recording medium as claimed in claim 1, wherein the resin of binder (2)(a) has a softening temperature of 150° C. or less, an average molecular weight of about 10,000 to about 200,000 and a degree of polymerization of from about 200 to about 500.
Claim 14
Dependent Claim
53 words
The magnetic recording medium as claimed in claim 12, wherein a resin used in the backing layer other than the resin having a 100% modulus of from 15 to 150 kg/cm 2 is selected from the group consisting of a vinyl chloride resin, a vinyl acetate resin, a acrylonitrile resin and cellulose derivatives.
Claim 15
Dependent Claim
23 words
The magnetic recording medium as claimed in claim 1, wherein the dry thickness of the backing layer is from 1.5 to 2.5 μm.
Claim 16
Dependent Claim
17 words
The magnetic recording medium as claimed in claim 1 in the form of a magnetic recording tape.
Claim 17
Dependent Claim
22 words
The magnetic recording medium as claimed in claim 15, wherein the non-magnetic support has a thickness of from 2.5 to 100 μm.
Claim 18
Dependent Claim
22 words
The magnetic recording medium as claimed in claim 16, wherein the non-magnetic support has a thickness of from 3 to 40 μm.
Claim 19
Dependent Claim
33 words
The magnetic recording medium as claimed in claim 1, wherein the non-magnetic particles in the backing layer other than the carbon black have an average particle diameter of from 0.01 to 3 μm.
Claim 20
Dependent Claim
33 words
The magnetic recording medium as claimed in claim 18, wherein the non-magnetic particles in the backing layer other than the carbon black have an average particle diameter of from 0.01 to 1 μm.
Claim 21
Dependent Claim
31 words
The magnetic recording medium as claimed in claim 1, wherein the weight ratio of the non-magnetic powder to all of the binders in the backing layer is from 200:100 to 50:100.
Claim 22
Dependent Claim
31 words
The magnetic recording medium as claimed in claim 20, wherein the weight ratio of the non-magnetic powder to all of the binders in the backing layer is from 200:100 to 75:100.
Claim 23
Dependent Claim
37 words
The magnetic recording medium as claimed in claim 1, wherein the amount of the polyisocyanate is in the range of from 15 to 30 wt% based on the total amount of the binders in the backing layer.
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) | 1990-03-09 | 1990-09-08 | 1991-03-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-03-09 | 1994-09-08 | 1995-03-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-03-09 | 1998-09-08 | 1999-03-10 | $7700.00 | Window Closed / Lapsed |