US4468436A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording material
Assignee: Fujifilm Holdings Corp
•
Filing: 1982-12-23
•
Granted: 1984-08-28
•
Expires: 2002-12-23
Abstract
Abstract A magnetic recording material and a process for producing it are disclosed. The material is excellent in abrasion resistance and has good electric characteristics. The material is obtained by coating on a support a subbing layer having a compound which contains a compound having an unsaturated bond polymerizable upon irradiation with electron beams. Upon the subbing layer is coated a ferromagnetic layer which contains a compound having an unsaturated bond polymerizable upon irradiation with electron beams, an organic solvent capable of dissolving the compound, and a ferromagnetic fine powder. The material is then subjected to an electron-beam irradiating processing to result in the hardening of the subbing and ferromagnetic layers through polymerization.
Inventors
- 👤 Tsutomu Okita
- 👤 Kiritani Masataka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 20:39
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/73; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31551; Y10T428/31554; Y10T428/31609; Y10T428/31855; Y10T428/31909; Y10T428/31928
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
107 words
A magnetic recording material produced by a process comprising the steps of: providing a subbing layer on a surface of a support base, the subbing layer comprising a compound having an unsaturated bond polymerizable upon irradiation with electron beams; coating a composition on the subbing layer, the composition comprising (a) a compound having an unsaturated bond polymerizable upon irradiation with electron beams, (b) an organic solvent capable of dissolving the compound, and (c) a ferromagnetic powder; irradiating the subbing layer and coated composition with sufficient electron beam irradiation to cause polymerization and hardening of the subbing layer compound and the compound (a) containing the ferromagnetic powder (c).
Claim 2
Dependent Claim
107 words
A magnetic recording material produced by a process comprising the steps of: providing a subbing layer on a surface of a support base, the subbing layer comprising a compound having an unsaturated bond polymerizable upon irradiation with electron beams; coating a composition on the subbing layer, the composition comprising (a) a compound having an unsaturated bond polymerizable upon irradiation with electron beams, (b) an organic solvent capable of dissolving the compound, and (c) a ferromagnetic powder; irradiating the subbing layer and coated composition with sufficient electron beam irradiation to cause polymerization and hardening of the subbing layer compound and the compound (a) containing the ferromagnetic powder (c).
Claim 3
Dependent Claim
33 words
A magnetic recording material produced by the process as claimed in claim 1, wherein the compound (a) having an unsaturated bond polymerizable upon irradiation, and containing the ferromagnetic powder (c), is polyurethane acrylate.
Claim 4
Dependent Claim
48 words
A magnetic recording material produced by the process as claimed in claim 1, wherein the subbing layer compound having an unsaturated bond polymerizable upon irradiation with electron beams is selected from the group consisting of an acrylonitrile-butadiene copolymer, a polyurethaneacrylate oligomer, a polyester-acrylate oligomer and a polyetheracrylate oligomer.
Claim 5
Dependent Claim
41 words
A magnetic recording material produced by the process as claimed in claim 1, wherein the irradiating is carried out with electron-beam irradiation with an accelerating voltage of 100 to 1,000 KV to provide an absorption dose of 0.5 to 20 megarad.
Claim 6
Dependent Claim
31 words
A magnetic recording material produced by the process as claimed in claim 1, wherein the compounds having an unsaturated bond have a molecular weight within the range of 1,000 to 20,000.
Claim 7
Dependent Claim
36 words
A magnetic recording material produced by the process as claimed in claim 1, wherein the ferromagnetic powder is selected from the group consisting of ferromagnetic iron oxide particles, ferromagnetic chromium dioxide particles and ferromagnetic alloy particles.
Claim 8
Dependent Claim
41 words
A magnetic recording material produced by the process as claimed in claim 6, wherein the particles have an axial ratio ranging from about 2:1 to about 20:1 and an average length in the range of about 0.2 to about 2.0 μm.
Claim 9
Dependent Claim
36 words
A magnetic recording material produced by the process as claimed in claim 1, wherein the weight ratio of the compound having an unsaturated bond to the ferromagnetic powder is within the range of 2:1 to 1:20.
Claim 10
Dependent Claim
26 words
A magnetic recording material produced by the process as claimed in claim 8, wherein the weight ratio is within the range of from 1:1 to 1:10.
Claim 11
Dependent Claim
27 words
A magnetic recording material produced by the process as claimed in claim 1, wherein the subbing layer has a thickness within the range of 0.1 to 0.5μ.
Claim 12
Dependent Claim
34 words
A magnetic recording material produced by the process as claimed in claim 1, wherein the composition is coated on the subbing layer as a layer having a dry thickness of 0.5 to about 15μ.
Claim 13
Dependent Claim
37 words
A magnetic recording material produced by the process as claimed in claim 1, further comprising the step of drying the coated composition with an air flow at a temperature within the range of 50° to 120° C.
Claim 14
Dependent Claim
26 words
A magnetic recording material produced by the process as claimed in claim 1, further comprising the step of orienting the ferromagnetic powder before irradiating the composition.
Claim 15
Dependent Claim
26 words
A magnetic recording material produced by a process as claimed in claim 1, further comprising the step of smoothening the composition coated on the subbing layer.
Claim 16
Dependent Claim
47 words
A magnetic recording material produced by the process as claimed in claim 14, wherein the smoothening is carried out by a calendering process wherein the roll pressure is within the range of about 25 to 100 Kg/cm 2 at a temperature of about 10° to 150° C.
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) | 1987-08-28 | 1988-02-27 | 1988-08-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-08-28 | 1992-02-27 | 1992-08-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-08-28 | 1996-02-27 | 1996-08-28 | $7700.00 | Window Closed / Lapsed |