Circuit writer materials
First Claim
1. An extrudable polymer thick film material for producing electrically conductive traces on a substrate comprising a mixture of an epoxy resin, a hardener for said epoxy resin, conductive particles, and at least two solvents,a first one of said solvents being relatively volatile as compared with a second one of said solvents, said solvents being present in quantities and in proportions relative to one another which permit said mixture to be extruded through a nozzle and such that said mixture has a viscosity of between 15,000 and 30,000 centipoise at a static shear rate of 20/sec and a viscosity of from one million to five million centipoise at a shear rate of about 0.01/secsaid conductive particles comprising from 85% to 95% by weight of said mixture, and said resin and hardener comprising 10% to 15% by weight of the mixture.
3 Assignments
0 Petitions
Accused Products
Abstract
Materials are disclosed which are used to produce traces on a circuit board by means of extrusion. The materials are polymer thick films (PTF) which are thixotropic. Conductive traces are composed of conductive particles, a resin and hardener, and two solvents, one having a relatively high volatility and one having a relatively low volatility. Thus when a newly deposited trace is subjected to a stream of hot air, the fast solvent will substantially evaporate leaving a firm paste behind over which another layer of PTF can be written without causing interference between the layers. The slow solvent then permits the various layers of traces to be polymerized together at the same time in a one step operation. The insulative material is similar to the conductive material in that it includes a resin and hardener and two solvents of differening volatility. In addition, in the preferred mode, it includes a gelling agent.
-
Citations
5 Claims
-
1. An extrudable polymer thick film material for producing electrically conductive traces on a substrate comprising a mixture of an epoxy resin, a hardener for said epoxy resin, conductive particles, and at least two solvents,
a first one of said solvents being relatively volatile as compared with a second one of said solvents, said solvents being present in quantities and in proportions relative to one another which permit said mixture to be extruded through a nozzle and such that said mixture has a viscosity of between 15,000 and 30,000 centipoise at a static shear rate of 20/sec and a viscosity of from one million to five million centipoise at a shear rate of about 0.01/sec said conductive particles comprising from 85% to 95% by weight of said mixture, and said resin and hardener comprising 10% to 15% by weight of the mixture.
Specification