Flexible screen-printable conductive composition

• US 4,425,263 A
• Filed: 11/02/1981
• Issued: 01/10/1984
• Est. Priority Date: 06/03/1981
• Status: Expired due to Fees

• Current Assignee: E. I. du Pont de Nemours and Company (Corteva, Inc.)
• Original Assignee: E. I. du Pont de Nemours and Company (Corteva, Inc.)
• Inventors: Nazarenko, Nicholas
• Primary Examiner(s): Barr, Josephine
• Application Number:
  US06/317,278
• Time in Patent Office: 799 Days
• Field of Search: 252/514, 252/513, 252/512, 252/511, 252/518, 252/519, 106/1.14, 106/1.19, 106/1.18, 106/290, 106/1.23, 106/308, 106/1.24, 106/311, 200/265, 200/292
• US Class Current: 252/511
• CPC Class Codes: C09D 11/104 Polyesters
• CPC Class Codes: H01B 1/22 the conductive material comprising metals or alloys
• CPC Class Codes: H01B 1/24 the conductive material comprising carbon-silicon compounds, carbon or silicon
• CPC Class Codes: H01H 13/702 with contacts carried by or formed from layers in a multilayer structure, e.g. membrane switches
• CPC Class Codes: H01H 13/785 characterised by the material of the contacts, e.g. conductive polymers
• CPC Class Codes: H01H 2201/026 non precious
• CPC Class Codes: H01H 2209/03 elastomeric
• CPC Class Codes: H01H 2209/074 elastomeric
• CPC Class Codes: H01H 2229/002 Screen printing
• CPC Class Codes: H01H 2229/004 Conductive ink
• CPC Class Codes: H01H 2229/018 Testing
• CPC Class Codes: H05K 1/095 for polymer thick films, i.e. having a permanent organic polymeric binder

Abstract

A screen-printable thick film conductor composition for membrane switches consisting of an active phase of conductive metal powder dispersed in an organic medium consisting essentially of a linear aromatic polyester resin dissolved in volatile solvent.

Claims

1. A screen-printable composition consisting essentially of (a) 30-80% by weight finely divided particles of conductive material selected from the group consisting of silver, nickel, copper, carbon, iron, gold, platinum, palladium and mixtures and alloys thereof dispersed in (b) 70-20% by weight organic medium which is a solution of linear aromatic polyester resin having an intrinsic viscosity of 0.5 to 1 completely dissolved in a volatile nonhydrocarbon solvent having a boiling point of 150°

-220°

C., the weight ratio of resin to solvent being from 0.15 to 0.5.

2. The composition of claim 1 in which the conductive material is silver.

3. The composition of claim 1 in which the conductive material is a glass or organic polymer coated with a material selected from the group consisting of silver, copper and nickel.

4. The composition of claim 1 in which the intrinsic viscosity of the polyester resin is 0.6 to 0.85.

5. The composition of claim 1 in which the polyester resin is the polycondensation product of a C_2-4 alkylene glycol with either isopthalic or terephthalic acid.

6. The composition of claim 5 in which the polyester resin is poly(ethylene terephthalate).

7. The composition of claim 1 in which the solvent has a boiling range of 150°

to 220°

C.

8. The composition of claim 7 in which the solvent is carbitol acetate.

9. The composition of claim 8 in which the solvent is admixed with 1-methyl ethylene glycol butylether.