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US 4,359,516 AGranted
Magnetic resist printing process, composition, and apparatus
AssigneeE. I. Du Pont de Nemours and Company
InventorsGeorge R. Nacci, Donald G. Pie
Life of this patent
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AssigneeE. I. Du Pont de Nemours and Company
InventorsGeorge R. Nacci, Donald G. Pie
Estimating the term…
A process of forming an image of toner on a latent magnetic image in a magnetic member followed by direct transfer to and coalescence on a surface to form a resist is disclosed. The surface portion not protected by the transferred resist toner image is then permanently modified by etching or plating. Chemically milled shapes are prepared as well as printed circuits and printing plates. The printed circuits may be formed by (1) etching away areas of a metal surface not protected by the resist, (2) electroless plating on areas not protected by the resist or (3) electroplating areas of a metal surface not protected by the resist, removing the resist, and in the case of (2) and (3), etching away the metal previously covered by the resist. An especially useful toner which forms a resist composition comprises a binder of thermoplastic resin and plasticizer and magnetic material present in the binder, compounded to have a tack transfer temperature of no greater than 110.degree. C.
A dry particulate resist composition of particles having an average size of 1 to 30 .mu.m, a melt index of 1 to 100 and a glass transition temperature from 25.degree. C. to 100.degree. C., for substantially instantaneous application to a heated surface to form a resist image capable of withstanding modification of an exposed area of said surface, comprising
A dry resist composition of particles having an average particle size of 1 to 30 .mu.m, and comprising 35 to 65% by wt. of coalescible binder component and 45 to 65% by weight based on the weight of the composition of magnetic material having an average particle size up to 6 .mu.m present in said particles, said binder component composed of thermoplastic polyester resin and 5 to 15% by wt. of plasticizer for said resin based on the total weight of said binder component, said composition being non-blocking at ordinary room temperature and resistant to aqueous FeCl.sub.3 etchant and having a melt index of 2 to 100, glass transition temperature of 25.degree. to 110.degree. C. and tack transfer temperature of 50.degree. to 110.degree. C. and tack transfer window of at least 20.degree. C., said resin having a weight average molecular weight of 1,000 to 50,000 and being adherent to copper at said tack transfer temperature.
Dependencies are inferred from the claim text.