Pressure sensitive ink means, and methods of use

• US 5,989,700 A
• Filed: 01/05/1996
• Issued: 11/23/1999
• Est. Priority Date: 01/05/1996
• Status: Expired due to Term

• Current Assignee: Tekscan, Inc.
• Original Assignee: Tekscan, Inc.
• Inventors: Krivopal, Boris
• Primary Examiner(s): McCamish, Marion
• Assistant Examiner(s): Guarriello, John J.
• Application Number:
  US08/583,444
• Time in Patent Office: 1,418 Days
• Field of Search: 428/215, 428/323, 523/161, 524/495, 524/496, 524/493, 73/763, 73/862.68, 73/88
• US Class Current: 428/323
• CPC Class Codes: G01L 1/20 by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids of piezo-resistive materials G01L1/18; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress
• CPC Class Codes: Y10T 428/24967 Absolute thicknesses specified
• CPC Class Codes: Y10T 428/25 Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles

Abstract

Pressure sensitive inks have selected pressure sensitivity designed for use as a pressure sensitive component of a pressure sensitive device. The ink of the device is formed of an elastic polymer binder with a filler therefor of semiconductive nanoparticles preferably uniformly dispersed in the binder.

Claims

1. In a pressure sensitive device for obtaining a variation in electrical resistance with variation in pressure applied to said device, said device having a pressure sensitive component extending between points for measurement of resistance through said pressure sensitive component, the improvement comprising,

said pressure sensitive component comprising at least one layer of solidified pressure sensitive ink forming at least a portion of said device positioned between said points of measurement so that pressure applied to said portion can produce a variation in electrical resistance which can be measured,

said ink comprising a polymeric binder and nanoparticles disbursed in said binder, said nanoparticles having a particle size in the range of from 1-1,000 nanometers with said layer having a sensitivity in the range of from about 0.2 to 60,000 micro Siemens/lb. and said nanoparticles comprising from about 1 to about 10% by weight of said ink.

2. The improvement of claim 1 wherein said particles are uniformly distributed carbon particles and said polymeric binder is an elastic phenoxy resin.

3. The improvement of claim 2 wherein said pressure sensitive component comprises two contacting layers of said ink.

4. The improvement of claim 3 wherein said two contacting layers each have a range of thickness from 0.00005 to 0.05 inch.

5. The improvement of claim 2 wherein said nanoparticles have a particle size in the range from 13 to 75 nanometers.

6. The improvement of claim 1 wherein said particles are semiconductive particles comprising from 1-7% by weight of said ink and have an average particle size in the range of 13 to 75 nanometers.

7. The improvement of claim 6 wherein said pressure sensitive component has a resistivity of from 10² -10⁷ ohm centimeters and said particles are carbon particles.

8. The improvement of claim 6 wherein said polymeric binder is a phenoxy resin and said particles are carbon particles.