Polyparabanic acid/copper foil laminates obtained by direct solution casting
AssigneeExxon Research & Engineering Co.
InventorDon J. Henderson
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Abstract
This invention relates to processes and techniques for forming metal and/or plastic/polyparabanic acid (PPA) laminates particularly for use as a component of electrical and electronic systems, especially as flexible circuit materials. Laminate species not requiring intermediate adhesive layers, not fabricated from preformed PPA films and not requiring subsequent cross-linking or other curing reactions are preferred. Solvent casting of PPA is a preferred method of preparing such laminates.
Claims11
A process of forming coated articles of polyparabanic acid strongly adhered to a supportive substrate which comprises in combination the steps of:
- (a) forming a solution of polyparabanic acid with an inherent viscosity of 0.4-2.5 and a Brookfield viscosity of from 1000 to 50,000 cps, at least 25% of the polyparabanic acid being of an aromatic type,
- (b) coating a thin layer of said solution directly on a substrate in the absence of intermediate adhesives,
- (c) heating said thin layer of polyparabanic acid solution to evaporate the solvent from said film and,
- (d) recovering a coated article having a relatively dry layer of polyparabanic acid strongly adhered directly to said substrate.
A coated article suitable as a precursor for a laminate article comprising a layer of polyparabanic acid adhered to a layer of one of FEP or polyimide film said polyparabanic acid having an inherent viscosity of at least 0.05 but less than 0.4 and wherein at least 25% of the polyparabanic acid is an aromatic type.
Coated articles comprising FEP film coated with a polyparabanic acid wherein at least 25% of the polyparabanic acid is of the aromatic type.
Coated articles comprising high temperature resistant polyimide film coated with a polyparabanic acid wherein at least 25% of the polyparabanic acid is of the aromatic type.
Dependencies are inferred from the claim text.