US4428974A
Expired / Lapsed
US
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Process for producing magnetic recording material
Assignee: Fujifilm Holdings Corp
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Filing: 1982-12-07
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Granted: 1984-01-31
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Expires: 2002-12-07
Abstract
Abstract A process for producing a magnetic recording material having excellent electromagnetic characteristics and sufficient abrasion resistance is disclosed. The process comprises the steps of coating on a support a magnetic recording composition containing a compound having an unsaturated bond polymerizable by irradiation with electron beams, an organic solvent capable of dissolving the compound and a ferromagnetic powder. The compound is subjected in sequence to a coating process on a nonmagnetic support, irradiated with an electron beam in an atmosphere containing oxygen at a concentration of 10,000 ppm or more and subjected to a smoothening treatment utilizing a specular surface, followed by an electron beam irradiation in an atmosphere containing oxygen at a concentration of 3,000 ppm or less.
Inventors
- 👤 Tsutomu Okita
- 👤 Kyoichi Naruo
- 👤 Akira Ushimaru
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 06:40
CPC Classifications
B; B05; B05D; B05D3/00; B05D3/06; B05D3/068; G; G11; G11B; G11B5/00; G11B5/84; G11B5/842
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
99 words
A process for producing a magnetic recording material comprising the steps of: coating on a support a composition containing a compound having an unsaturated bond polymerizable by irradiation with electron beams, an organic solvent capable of dissolving said compound, and a ferromagnetic powder; irradiating the coated composition with electron beams in an atmosphere containing oxygen at a concentration of at least 10,000 ppm; subjecting the surface of the resulting composition to a smoothening treatment utilizing a specular surface; and irradiating the smoothened surface with electron beams in an atmosphere containing oxygen at a concentration of 3,000 ppm or less.
Claim 2
Dependent Claim
99 words
A process for producing a magnetic recording material comprising the steps of: coating on a support a composition containing a compound having an unsaturated bond polymerizable by irradiation with electron beams, an organic solvent capable of dissolving said compound, and a ferromagnetic powder; irradiating the coated composition with electron beams in an atmosphere containing oxygen at a concentration of at least 10,000 ppm; subjecting the surface of the resulting composition to a smoothening treatment utilizing a specular surface; and irradiating the smoothened surface with electron beams in an atmosphere containing oxygen at a concentration of 3,000 ppm or less.
Claim 3
Dependent Claim
43 words
The process for producing the magnetic recording material as claimed in claim 1, wherein the first electron beam irradiation is conducted at an accelerating voltage in the range of 100 to 1,000 kv and at an absorption dose of 0.1 to 10 megarad.
Claim 4
Dependent Claim
54 words
The process for producing the magnetic recording material as claimed in claim 1, wherein said smoothening treatment utilizing a specular surface is carried out using a 1- to 30-step calender comprising specular rolls and elastic rolls under a pressure of 25 to 100 kg/cm 2 at a calendering temperature of 10° to 100° C.
Claim 5
Dependent Claim
43 words
The process for producing the magnetic recording material as claimed in claim 1, wherein the second electron beam irradiation is conducted at an accelerating voltage in the range of 100 to 1,000 kv and at an absorption dose of 0.1 to 10 megarad.
Claim 6
Dependent Claim
40 words
The process for producing the magnetic recording material as claimed in claim 1, wherein the compound having an unsaturated bond polymerizable by irradiation with electron beams is a polymer having a molecular weight within the range of 1,000 to 20,000.
Claim 7
Dependent Claim
45 words
The process for producing the magnetic recording material as claimed in claim 1, wherein the ferromagnetic powder is comprised of ferromagnetic particles having an axial ratio ranging from about 2:1 to about 20:1 and having an average length of about 0.2 to about 2.0 μm.
Claim 8
Dependent Claim
33 words
The process for producing the magnetic recording material as claimed in claim 1, wherein the weight ratio of the compound having an unsaturated bond to the ferromagnetic powder ranges from 1:1 to 1:10.
Claim 9
Dependent Claim
29 words
The process for producing the magnetic recording material as claimed in claim 1, wherein the coated composition has a thickness within the range of 0.5 to about 15 μm.
Claim 10
Dependent Claim
38 words
The process for producing the magnetic recording material as claimed in claim 1, wherein the support is in the form of a film, tape or sheet and has a thickness within the range of 2 to 25 μm.
Claim 11
Dependent Claim
26 words
The process for producing the magnetic recording material as claimed in claim 4, wherein the accelerating voltage is in the range of 150 to 700 kv.
References Cited (Backward Citations)
US3216846A
Cited
US4343831A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-01-30 | 1987-08-01 | 1988-01-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-01-30 | 1991-08-01 | 1992-01-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-01-30 | 1995-08-01 | 1996-01-31 | $7700.00 | Window Closed / Lapsed |