US4543268A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electron-beam adhesion-promoting treatment of polyester film base for magnetic recording media
Assignee: 3M Co
•
Filing: 1984-07-05
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Granted: 1985-09-24
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Expires: 2004-07-05
Abstract
Abstract The magnetizable layer of a magnetic recording medium which has a flexible polyester film base is better adhered to the film base and better resists abrasion if the film base is first subjected to electron-beam irradiation while passing through an inert atmosphere such as nitrogen.
Inventors
- 👤 LuAnn Sidney
- 👤 Stephen R. Ebner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 16:31
CPC Classifications
B; B05; B05D; B05D3/00; B05D3/06; B05D3/068; B29; B29C; B29C59/00; B29C59/16; G; G11; G11B; G11B5/00; G11B5/62; G11B5/73; G11B5/739; G11B5/73923; G11B5/73927; G11B5/84; G11B5/8404; B05D2201/00; B05D2252/00; B05D2252/02; B29C35/00; B29C35/02; B29C35/08; B29C35/0866; B29C2035/0877; B29K; B29K2067/00; B29K2995/00; B29K2995/0037; B29K2995/005; B29K2995/0053; B29L; B29L2017/00; B29L2017/008; C; C09; C09J; C09J2483/00; C09J2483/005
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
118 words
In the manufacture of a magnetic recording medium comprising a flexible polyester film base and a thin magnetizable layer, a method for promoting the adhesion to the polyester film base of the magnetizable layer, which method comprises the steps of (1) continuously passing uncoated polyester film base through an inert atmosphere containing no more than 100 ppm oxygen while (2) exposing the film base to irradiation by an electron beam to subject the film base to an absorbed dosage of at least 2 Mrad and (3) applying a thin magnetizable layer containing an organic binder to a surface of the film base to which adhesion of the layer has been enhanced by virtue of steps (1) and (2).
Claim 2
Dependent Claim
118 words
In the manufacture of a magnetic recording medium comprising a flexible polyester film base and a thin magnetizable layer, a method for promoting the adhesion to the polyester film base of the magnetizable layer, which method comprises the steps of (1) continuously passing uncoated polyester film base through an inert atmosphere containing no more than 100 ppm oxygen while (2) exposing the film base to irradiation by an electron beam to subject the film base to an absorbed dosage of at least 2 Mrad and (3) applying a thin magnetizable layer containing an organic binder to a surface of the film base to which adhesion of the layer has been enhanced by virtue of steps (1) and (2).
Claim 3
Dependent Claim
21 words
Method as defined in claim 1 wherein the magnetizable layer applied in step (3) comprises magnetizable particles dispersed in organic binder.
Claim 4
Dependent Claim
15 words
Method as defined in claim 2 wherein said binder comprises polyurethane elastomer and phenoxy resin.
Claim 5
Dependent Claim
14 words
Method as defined in claim 1 wherein the dosage does not exceed 20 Mrad.
Claim 6
Dependent Claim
15 words
Method as defined in claim 4 wherein the dosage is from 5 to 10 Mrad.
Claim 7
Dependent Claim
13 words
Method as defined in claim 1 wherein the inert atmosphere is substantially nitrogen.
Claim 8
Dependent Claim
16 words
Method as defined in claim 1 wherein the inert atmosphere contains less than 40 ppm oxygen.
Claim 9
Dependent Claim
21 words
Method as defined in claim 7 wherein the polyester film base is at approximately atmospheric pressure during steps (1) and (2).
Claim 10
Dependent Claim
28 words
Method as defined in claim 1 wherein the polyester film base is continuously irradiated in step (2) at a web speed of at least 100 meters per minute.
Claim 11
Dependent Claim
12 words
Method as defined in claim 1 wherein the polyester is poly(ethylene terephthalate).
Claim 12
Dependent Claim
33 words
Method as defined in claim 10 wherein the film base is unsupported while being irradiated in step (2), and the adhesion of magnetizable layers to both faces of the film base is enhanced.
Claim 13
Dependent Claim
35 words
Method as defined in claim 10 wherein the polyester film base contacts a metal surface while being irradiated in step (2), and adhesion to only the noncontacting face of the film base is satisfactorily enhanced.
Claim 14
Dependent Claim
30 words
Method as defined in claim 1 wherein the magnetizable layer is applied in step (3) to the surface of the film base which faced the electron-beam radiation in step (2).
Claim 15
Dependent Claim
19 words
The method of claim 1 wherein the electron beam has an accelerating voltage of at least 150 kiloelectron volts.
Claim 16
Dependent Claim
13 words
The method of claim 1 wherein the film base is biaxially oriented polyester.
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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) | 1988-09-23 | 1989-03-25 | 1989-09-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-09-23 | 1993-03-25 | 1993-09-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-09-23 | 1997-03-25 | 1997-09-24 | $7700.00 | Window Closed / Lapsed |