US4874549A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pressure sensitive electro-conductive materials
Assignee: PIVOTECH Inc
•
Filing: 1988-04-26
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Granted: 1989-10-17
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Expires: 2008-04-26
Abstract
Abstract The invention relates to a pressure sensitive electro-conductive material which can be utilized as a pressure sensitive electro-conductive switch or as a variable resistor. The switch comprises two electrodes with a deformable pressure sensitive electro-conductive material sandwiched between the electrodes. The electro-conductive material comprises a deformable elastomeric material impregnated with a plurality of electro-conductive micro-agglomerates of unbound finely divided electro-conductive carbon particles enclosed by a matrix of the elastomeric material and finely divided electro-conductive carbon particles bound together by the elastomeric material.
Inventors
- 👤 Michael Michalchik
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 19:59
CPC Classifications
H; H01; H01B; H01B1/00; H01B1/20; H01B1/24; H01C; H01C10/00; H01C10/10; H01C10/106
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
126 words
A process for the preparation of a pressure sensitive electro-conductive material comprising the steps of: a. Preparing a solvent system comprising water, a water miscible carbon-wetting organic solvent, and a surfactant; b. Mixing finely divided electro-conductive carbon particles into the solvent system to form a uniform slurry; c. Maintaining the slurry for a predetermined period of time to obtain substantial wetting of the carbon particles of the solvent system to form a pre-agglomeration composition; d. Dispersing the pre-agglomeration composition into an aqueous elastomeric composition to form an elastomeric-carbon composition containing electrically conductive micro-agglomerates comprising unbound finely divided electro-conductive carbon particles enclosed by a matrix of elastomeric material and bound finely divided electro-conductive carbon particles; and e. Drying said elastomeric-carbon composition to obtain the pressure-sensitive electroconductive material.
Claim 2
Dependent Claim
126 words
A process for the preparation of a pressure sensitive electro-conductive material comprising the steps of: a. Preparing a solvent system comprising water, a water miscible carbon-wetting organic solvent, and a surfactant; b. Mixing finely divided electro-conductive carbon particles into the solvent system to form a uniform slurry; c. Maintaining the slurry for a predetermined period of time to obtain substantial wetting of the carbon particles of the solvent system to form a pre-agglomeration composition; d. Dispersing the pre-agglomeration composition into an aqueous elastomeric composition to form an elastomeric-carbon composition containing electrically conductive micro-agglomerates comprising unbound finely divided electro-conductive carbon particles enclosed by a matrix of elastomeric material and bound finely divided electro-conductive carbon particles; and e. Drying said elastomeric-carbon composition to obtain the pressure-sensitive electroconductive material.
Claim 3
Dependent Claim
24 words
The process of claim 1 wherein the water miscible carbon-wetting organic solvent is miscible in the surfactant and the surfactant is soluble in water.
Claim 4
Dependent Claim
31 words
The process according to claim 1 wherein the pH of the solvent system is adjusted to between about 7 and about 10 by the addition of a water soluble volatile base.
Claim 5
Dependent Claim
24 words
The process according to claim 1 wherein the water soluble base is selected from the group consisting of ammonium hydroxide and methyl diethanol amine.
Claim 6
Dependent Claim
26 words
The process according to claim 1 wherein the finely divided electro-conductive carbon particles have a particle size of from about 15 millimicrons to about 75 millimicrons.
Claim 7
Dependent Claim
33 words
The process according to claim 1 wherein the slurry in step c is maintained for a period of 1 to 7 days at ambient temperatures to obtain substantial wetting of the carbon particles.
Claim 8
Dependent Claim
30 words
The process according to claim 1 wherein the pH of the aqueous carbon slurry is adjusted to between about 7.0 and about 10.0 by the addition of a volatile base.
Claim 9
Dependent Claim
31 words
The process according to claim 1 wherein pH of the elastomeric-carbon composition is adjusted to a value from about 5.0 to about 10.0 by the addition of a water soluble base.
Claim 10
Dependent Claim
24 words
The process according to claim 8 wherein the water soluble base is selected form the group consisting of ammonium hydroxide and methyl diethanol amine.
Claim 11
Dependent Claim
15 words
The process according to claim 1 wherein the elastomeric composition is an aqueous polyurethane dispersion.
Claim 12
Dependent Claim
24 words
The process according to claim 1 wherein the elastomeric-carbon composition is formed into a film and dried to obtain a pressure sensitive electro-conductive material.
Claim 13
Dependent Claim
18 words
The process according to claim 10 wherein the film of elastomeric-carbon composition is formed on an electro-conductive substrate.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-10-16 | 1993-04-17 | 1993-10-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-10-16 | 1997-04-17 | 1997-10-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-10-16 | 2001-04-17 | 2001-10-17 | $7700.00 | Window Closed / Lapsed |