Electrically conductive coating composition for providing a bend sensor
First Claim
1. An electrically conductive composition for coating on a flexible polyester film substrate and providing a bend sensor in electronic circuits comprisinga) a polymeric binder system comprising phenolic resin that dries and/or cures to a brittle coating which cracks when bent around a mandrel;
- b) an amount of discontinuous conductive carbon black ranging from about 3 to 20 wt. percent based on the weight of the binder effective to produce a desired electrical resistance in the composition;
c) graphite particles in an amount effective to stabilize the resistance profile of the composition after cracking on a mandrel and less than the amount that produces a composition having a resistance ratio (bent/straight) equal to 1;
1, andd) a thermoplastic additive to improve adhesion of the composition to said polyester substrate, said additive comprising thermoplastic resin containing acrylic resin, vinyl resin and polyurethane, surfactant and organic solvent therefor.
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Abstract
A composition is disclosed which forms a bend sensor when coated on a flexible substrate. A bend sensor prepared from the composition is also disclosed. The composition contains a brittle binder which cracks under a stress, electrically conductive elements and a graphite additive which stabilizes the degree of cracking. The composition forms a bend sensor which upon a change in degree of flexing produces an electrical signal in the form of a change in resistance in circuits which include the sensor.
15 Citations
2 Claims
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1. An electrically conductive composition for coating on a flexible polyester film substrate and providing a bend sensor in electronic circuits comprising
a) a polymeric binder system comprising phenolic resin that dries and/or cures to a brittle coating which cracks when bent around a mandrel; -
b) an amount of discontinuous conductive carbon black ranging from about 3 to 20 wt. percent based on the weight of the binder effective to produce a desired electrical resistance in the composition; c) graphite particles in an amount effective to stabilize the resistance profile of the composition after cracking on a mandrel and less than the amount that produces a composition having a resistance ratio (bent/straight) equal to 1;
1, andd) a thermoplastic additive to improve adhesion of the composition to said polyester substrate, said additive comprising thermoplastic resin containing acrylic resin, vinyl resin and polyurethane, surfactant and organic solvent therefor. - View Dependent Claims (2)
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Specification