Stock material or miscellaneous articles – Circular sheet or circular blank – Recording medium or carrier
Patent
1976-02-09
1977-09-06
Pianalto, Bernard D.
Stock material or miscellaneous articles
Circular sheet or circular blank
Recording medium or carrier
427129, 428327, 428329, 428339, 428418, 428539, 428900, H01F 1002
Patent
active
040469328
ABSTRACT:
The invention relates to a process for the manufacture of improved magnetic discs by applying a thin layer of a liquid dispersion of magnetic pigments and optionally further, non-magnetic, pigments in a binder mixture to a non-magnetic rigid base, and curing the magnetic coating which has been applied. The binder used is a mixture of polycondensates comprising 60 to 70% by weight of a solid curable polycondensate of 2,2-bis(4-hydroxyphenyl)-propane and epichlorohydrin having an epoxy equivalent weight from about 400 to 2,500 and a melting point from about 50.degree. to 150.degree. C, 10 to 30% by weight of a curable allyloxybenzene-formaldehyde condensate of the resol type with free methylol groups or with methylol groups etherified with a lower alcohol, and having a molecular weight of less than 1,000, and 10 to 30% by weight of a curable melamine-formaldehyde condensate with more than two methylol groups etherified with n-butanol or iso-butanol, and having a molecular weight of less than 2,500. A magnetic dispersion using such a binder allows the application of a firmly adhering magnetic coating, even in thicknesses of less than 4 .mu., to aluminum discs or pre-coated aluminum discs, and the magnetic coating produced has high resistance to mechanical wear.
REFERENCES:
patent: 3320090 (1967-05-01), Graubart
patent: 3366505 (1968-01-01), Bisschops et al.
patent: 3474073 (1969-10-01), Higashi
patent: 3560388 (1971-02-01), Higashi
patent: 3647539 (1972-03-01), Weber
patent: 3689317 (1972-09-01), Akashi et al.
patent: 3781210 (1973-12-01), Lohoff
patent: 3821025 (1974-06-01), Akashi et al.
Balz Werner
Falk Roland
Gawlik Peter
Hartmann Hans-Joerg
Motz Herbert
BASF - Aktiengesellschaft
Pianalto Bernard D.
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