Printed circuit board

• US 4,863,757 A
• Filed: 02/06/1987
• Issued: 09/05/1989
• Est. Priority Date: 02/06/1987
• Status: Expired due to Fees

• Current Assignee: Poly-Flex Circuits Incorporated (PARLEX USA LLC)
• Original Assignee: Key-Tech, Inc.
• Inventors: Durand, David
• Primary Examiner(s): Niebling, John F.
• Assistant Examiner(s): GORGOS, KATHRYN L
• Application Number:
  US07/011,975
• Time in Patent Office: 942 Days
• Field of Search: 204/155, 204/157.15, 427/54.1, 427/96, 427/47, 430/31, 430/311, 430/325
• US Class Current: 427/510
• 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 2201/083 Magnetic materials
• CPC Class Codes: H05K 2203/104 Using magnetic force, e.g. to align particles or for a temporary connection during processing
• CPC Class Codes: H05K 3/1283 After-treatment of the printed patterns, e.g. sintering or curing methods
• CPC Class Codes: H05K 3/245 Reinforcing conductive patterns made by printing techniques or by other techniques for applying conductive pastes, inks or powders; Reinforcing other conductive patterns by such techniques

Abstract

A method for producing a circuit board having conductive circuit elements patterened on a non-conductive substrate involves printing a film of a U.V. curable ink composed of a suspension of silver-coated magnetite particles in a U.V. curable resin onto the substrate in a circuit pattern, subjecting the pattern to a magnetic field to move the magnetite particles to a position at or near the upper surface of the resin and effecting U.V. radiation cure of the U.V. curable ink.

Claims

1. A method for producing a circuit board having conductive circuit elements with a specific resistivity of less than 0.05 ohm/cm² patterned on a non-conductive substrate comprising

a. printingn a film of U.V. curable ink onto the non-conductive substrate in a desired circuit pattern, said U.V. curable ink comprising a suspension of silver-coated magnetite particles in a U.V. curable resin.

b. subjecting the resulting printed circuit pattern to a magnetic field sufficient to move the magnetite particles to a position at or near the upper surface of the resin without breaking the surface tension thereof or substantially increasing the thickness of the ink film from said substrate and

c. effecting U.V. radiation cure of the U.V. curable ink by exposing said U.V. curable ink to a U.V. source having an output in the region between 360 nm and 420 nm for a time sufficient to cure said U.V. curable ink.

2. The method of claim 1 wherein said U.V. curable ink comprises a mixture of a cycloaliphatic epoxy resin, and a cationic photoinitiator.

3. The method of claim 2 wherein said U.V. curable resin also contains, as a plasticizer, a plasticizing amount of a polyether polyol.

4. The method of claim 1 wherein said U.V. curable ink contains by volume 25 to 67 percent silver coated magnetite spheres based on the total volume of said curable ink.