Patent · US Expired

Method of applying a transparent magnetic layer to a web or sheet material

US5573897A · kind A · utility

2Cited by

9References

16Claims

0Family size

Assignee

Agfa-Gevaert NV · BE

Inventors

Hartwig Andries · Mortsel, BE
Werner Krafft · Leverkusen, DE
Willem Mues · Tremelo, BE
Jan Gilleir · Mortsel, BE

Key dates

Filing date	Nov 28, 1994
Grant date	Nov 12, 1996
Priority date	—
Expiry date	Nov 28, 2014

Classification

Technology area (CPC G)Physics
CPC primaryG11B5/725
WIPO fieldAudio-visual technology
WIPO sectorElectrical engineering

Abstract

A method is provided for applying a magnetic layer onto a polymeric sheet or web material comprising the steps of (i) simultaneously coextruding a non magnetic "dummy" layer and a magnetic layer onto said polymeric sheet or web material, said non magnetic "dummy" layer being closest to the support (ii) drying the coextruded layers characterised in that the sum of the wet coating thickness of said "dummy" layer (Th.sub.dum) and of the wet coating thickness of said magnetic layer (Th.sub.mag) fulfils the equation 25 .mu.m.ltoreq.Th.sub.dum +Th.sub.mag .ltoreq.100 .mu.m and that the ratio of (Th.sub.mag) to (Th.sub.dum) fulfils the equation 0.01.ltoreq.Th.sub.mag /Th.sub.dum .ltoreq.1.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.