Method of making transparent magnetic recording layers
US5520954A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 10, 1995 |
| Grant date | May 28, 1996 |
| Priority date | — |
| Expiry date | Mar 10, 2015 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/31768
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method of making a transparent magnetic recording layer which comprises forming a concentrated aqueous magnetic dispersion (A) of from 10 to 50 percent by weight ferromagnetic particles having a specific surface area of at least 30 m.sup.2 /gm and from 0.5 to 20 percent by weight of a dispersing agent; adding the concentrated aqueous magnetic dispersion (A) to a viscosity increasing hydrophilic polymer in water (B) such that the concentration of the hydrophilic cobinder is from 0.5 to 3 percent by weight based on the total weight of (A) and (B); diluting the resulting dispersion (A) plus (B) with water to give a dispersion (C) having a concentration of from 0.5 to 5 percent by weight of ferromagnetic particles; preparing a final dispersion by adding to the dispersion (C) from 20 to 200 parts per 100 parts of dispersion (C) of an aqueous deionized gelatin solution having a pH value from 7 to 10 and containing from 2 to 15 percent by weight of gelatin and coating the final dispersion onto a substrate to give a dry coverage of from 700 mg/m.sup.2 to 3000 mg/m.sup.2 of solids.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.