Flexible screen-printable conductor composition

• US 4,371,459 A
• Filed: 12/17/1981
• Issued: 02/01/1983
• Est. Priority Date: 12/17/1981
• Status: Expired due to Term

• 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, J. L.
• Application Number:
  US06/331,893
• Time in Patent Office: 411 Days
• Field of Search: 252/514, 252/512, 252/513, 252/511, 252/518, 106/1.14, 106/1.19, 106/290, 106/308 M, 106/311, 200/265, 200/292, 428/901, 428/457, 428/458, 428/412, 428/421, 428/480, 428/482, 427/88, 427/96, 427/282, 427/102, 427/123, 427/125, 427/393.5, 427/372 R, 29/622, 29/624, 29/625, 29/630 R
• US Class Current: 252/514
• CPC Class Codes: C09D 11/52 Electrically conductive inks
• CPC Class Codes: H01B 1/22 the conductive material comprising metals or alloys
• 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
• CPC Class Codes: Y10S 428/901 Printed circuit
• CPC Class Codes: Y10T 29/49105 Switch making

Abstract

Screen-printable conductor composition comprising (a) a conductive phase containing silver and base metal powders dispersed in a solution of (b) a multipolymer prepared by copolymerization of vinyl acetate, vinyl chloride, and an ethylenically unsaturated dicarboxylic acid and a linear aromatic polyester resin dissolved in (c) volatile nonhydrocarbon solvent.

Claims

1. A screen printable conductor composition comprising

a. 70-90% weight, basis total solids, of a conductive phase consisting essentially of finely divided particles of (1) 50-95% weight silver, and (2) 50-5% weight of a base metal selected from the group consisting of aluminum, tin and nickel and mixtures thereof dispersed in a solution of

b. 30-10% weight, basis total solids, of polymers consisting essentially of (1) 10-65% weight of a multipolymer prepared by copolymerization of vinyl acetate, vinyl chloride and 0.3-10% weight ethylenically unsaturated dicarboxylic acid in which the weight ratio of vinyl chloride to vinyl acetate is from 3 to 8 and (2) 90-35% by weight of a linear aromatic polyester resin having an intrinsic viscosity of 0.5-1 dissolved in

c. volatile nonhydrocarbon polar solvent in which the solvent has a boiling range of 150°

-220°

C.

2. The composition of claim 1 in which the base metal is aluminum.

3. The composition of claim 1 in which the base metal is tin.

4. The composition of claim 1 in which the dicarboxylic acid is maleic acid.

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

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

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

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

9. The composition of claim 7 in which the solvent ethylene glycol monoethylether acetate.

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

11. The composition of claim 1 comprising of 75-85% weight conductive phase and 25-15% weight polymers.

12. The composition of claim 1 in which the conductive phase consists essentially of 60-90% weight silver and 40-10% weight of base metal.

13. The composition of claim 1 in which the particles are no larger than 15 μ

m.

14. The composition of claim 13 in which the particles are 1-10 μ

m in size.

15. A method of making a membrane switching element comprising the sequential steps of

(a) applying to a flexible organic polymeric substrate a pattern coating of the composition of claim 1 and

(b) drying the coating to remove solvent therefrom.

16. A membrane switching element comprising a flexible organic polymer substrate having thereon a patterned coating of the composition of claim 1 which has been dried to remove solvent therefrom.