Polymer thick film encapsulant and enhanced stability PTC carbon system
AssigneeE. I. Du Pont de Nemours and Company
InventorsVince Arancio, Jay Robert Dorfman
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Abstract
The invention is directed to a polymer thick film encapsulant composition comprising thermoplastic fluoropolymer resin and acrylic resin dissolved in organic solvents. The deposited encapsulant composition is processed at a time and energy sufficient to remove all solvent and form an encapsulant. The invention is further directed to using the encapsulant composition to form an encapsulant in PTC heater circuitry and, in particular, in PTC heater circuitry in mirror heater and seat heater applications.
Claims7
A positive temperature coefficient heating circuit comprising an encapsulant formed from an encapsulant composition consisting essentially of:
- (a) 70-97 wt % of a first organic medium, based on the total weight of the encapsulant composition, said first organic medium comprising 30-60 wt % thermoplastic fluoropolymer resin dissolved in a first organic solvent, wherein the weight percent of said thermoplastic fluoropolymer resin is based on the total weight of said first organic medium;
- and
- (b) 3-30 wt % of a second organic medium, based on the total weight of the encapsulant composition, said second organic medium comprising 10-50 wt % acrylic resin dissolved in a second organic solvent, wherein the weight percent of said acrylic resin is based on the total weight of said second organic medium;
- wherein said encapsulant composition has been heated to remove all solvent.
A positive temperature coefficient heating circuit comprising an encapsulant formed from an encapsulant composition consisting essentially of:
- (a) 70-97 wt % of a first organic medium, based on the total weight of the encapsulant composition, said first organic medium comprising 30-60 wt % thermoplastic fluoropolymer resin dissolved in a first organic solvent, wherein the weight percent of said thermoplastic fluoropolymer resin is based on the total weight of said first organic medium;
- (b) 3-30 wt % of a second organic medium, based on the total weight of the encapsulant composition, said second organic medium comprising 10-50 wt % acrylic resin dissolved in a second organic solvent, wherein the weight percent of said acrylic resin is based on the total weight of said second organic medium;
- and
- (c) fumed silica;
- wherein said encapsulant composition has been heated to remove all solvent.
A heater with a positive temperature coefficient heating circuit comprising an encapsulant formed from the encapsulant composition consisting essentially of:
- (a) 70-97 wt % of a first organic medium, based on the total weight of the encapsulant composition, said first organic medium comprising 30-60 wt % thermoplastic fluoropolymer resin dissolved in a first organic solvent, wherein the weight percent of said thermoplastic fluoropolymer resin is based on the total weight of said first organic medium;
- and
- (b) 3-30 wt % of a second organic medium, based on the total weight of the encapsulant composition, said second organic medium comprising 10-50 wt % acrylic resin dissolved in a second organic solvent, wherein the weight percent of said acrylic resin is based on the total weight of said second organic medium;
- wherein said encapsulant composition has been heated to remove all solvent.
Dependencies are inferred from the claim text.