Thick film conductor compositions for use in membrane switch applications

• US 6,939,484 B2
• Filed: 12/04/2003
• Issued: 09/06/2005
• Est. Priority Date: 12/04/2003
• Status: Active Grant

• Current Assignee: Du Pont China Limited (DuPont de Nemours, Inc.)
• Original Assignee: E. I. du Pont de Nemours and Company (Corteva, Inc.)
• Inventors: Dorfman, Jay Robert
• Primary Examiner(s): KOPEC, MARK T
• Application Number:
  US10/728,142
• Publication Number:
  US 20050121657A1
• Time in Patent Office: 642 Days
• Field of Search: 252/514, 427/58, 427/66, 427/96, 200/512, 200/530, 200/265
• US Class Current: 252/514
• CPC Class Codes: H01B 1/22 the conductive material comprising metals or alloys
• CPC Class Codes: H05K 1/095 for polymer thick films, i.e. having a permanent organic polymeric binder
• CPC Class Codes: H05K 2201/015 Fluoropolymer, e.g. polytetrafluoroethylene [PTFE]

Abstract

The present invention relates to a thick film conductor composition comprising: (a) electrically conductive silver powder; (b) PVDF/HFP polymer resin, copolymers of a PVDF/HFP polymer resin, and mixtures thereof; dissolved in (c) organic solvent, with the provisos that the PVDF/HFP resin has a melt viscosity of 0.2–0.7 kPoise and a DSC melt temperature in the range of 85–98° C.

Claims

1. A thick film conductor composition comprising:

a) electrically conductive silver powder;

b) PVDF/HFP polymer resin, copolymers of a PVDF/HFP polymer resin, and mixtures thereof;

dissolved in

c) organic solvent;

with the provisos that the PVDF/HFP resin has a melt viscosity of 0.2–

0.7 kPoise and a DSC melt temperature in the range of 85–

98°

C.

2. The composition of claim 1 wherein the PVDF/HFP resin contains about 12–

16 mole % of hexafluoropropylene (HFP) in the total resin composition.

3. The composition of claim 1 wherein the boiling point of the organic solvent is in the range of 180°

C. to 250°

C.

4. The composition of claim 1 wherein the organic solvent is selected from the group comprising glycol ethers, ketones, esters, and mixtures thereof.

5. A method of forming a membrane touch switch comprising:

a) preparing the composition of claim 1;

b) applying the composition of a) onto a substrate;

c) drying the composition of b) to form a circuit; and

d) applying a voltage across the circuit of c).

6. A membrane touch switch utilizing the composition of claim 1.

7. A membrane touch switch formed by the method of claim 5.