This technology enables electrostatic painting of thermoplastics
without the need of conductive primers or coatings. The polymer composition
is modified to include electrically conductive materials that enable
molded articles made from these materials to become electrically conductive.
While numerous applications exist for electrically conductive polymers,
they are especially useful for painted articles. The molded articles
may be electrically grounded and painted with high-voltage electrostatic
painting equipment. This increases the transfer efficiency of the
painting process. Electrically conductive polymers may be used in
variety of automotive applications such as body panels, fascias, bumpers,
cladding and spoilers. While most automotive plastic components are
painted separately from the metal body, conductive plastics may be
secured to adjacent metal components and painted in the same paint
booth using the same painting equipment as the vehicle body. This
greatly simplifies the manufacturing process and improves color matching.
Conductive modification of the polymer material
was achieved by incorporation of commercially available high structure
conducting carbon blacks at cost effective levels (less than 5%).
These low additive levels were achieved by exploiting the phase structure
of multi-component polymer blends in which at least one component
is semi-crystalline and continuous. Molded components exhibit a surface-to-core
electrical resistivity variation associated with the dependence of
carbon aggregate structure on both thermal quenching at the mold wall
and shear history. Electrostatic painting performance equivalent to
steel is achieved by optimizing the internal, or core, electrical
resistance such that this value remains below 109 ohm/cm. This technology
represents an automotive industry first in electrostatic painting
of plastics.
Plastic body panel applications have seen
rapid growth in Europe and are making progress in penetrating the
North American market. In Europe, the Renault Clio and Megane Scenic,
Audi A2 and Daimler-Chrysler A-Class each use plastic panels for fenders
while the Clio and Opel Tigra also use plastics for their tailgates.
In addition, the Volkswagen Beetle also uses plastic body panels.
In North America, plastic panels have replaced steel for pick-up box
inners and outers on the F350 and Silverado and have been a staple
of the Saturn and Corvette brand for years.
Awards
This Ford technology won the 1997 Society of Plastics Engineers Most
Innovative Use of Plastics in the Materials category for its use on
the 1997 Mercury Sable front fascia. The inventors of this technology
also won a Henry Ford Technology Award in 1997.
Images
Benefits Summary
- Reduced Paint Usage
- Reduce Paint Sludge
- Improved Resistance to Surface Damage
- Improved Manufacturing Flexibility
- Good Low Temperature Performance
- Low-Cost Materials
Development Status
Ford has used electrically conductive polymers
in facilities in North America and Europe.
Licensees
FGTL has licensed one polymer manufacturer.
Patent Information
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| Patent No. |
Patent Title |
| 6,087,426 |
Thermoplastic ionic conductor |
| 5,959,015 |
Conductive modification of paintable mold-in color capable,
thermoplastic olefin formulation |
| 5,484,838 |
Thermoplastic compositions with modified electrical conductivity |
| 5,337,184 |
Acrylic thermoplastic ionic conductor |
| 5,328,961 |
Electrically conductive polythiophenecarbonyl polymer networks |
| 5,280,381 |
Process for preparing a solid polymeric fast ion conducting
layer for an electrochromic device |
| 5,276,102 |
Electrically conductive polythiopheneamine polymer networks |
| 5,274,046 |
Electrically conductive polypyrrolecarbonyl polymer networks |
| 5,254,627 |
Electrically conductive polypyrroleamine polymer networks |
| 5,186,813 |
Deposition of electroactive polymers |
| 5,128,013 |
Deposition of electroactive polymers |
| 5,100,523 |
Use of amorphous carbon to promote adhesion between electroactive
polymer films and conductive substrates |
| |
Publications
1) Helms, I.; Blais, E.; Cheung, M. -F.; Schroeder,
3.; Derengowski, T. "Conductive Modification of Injection Molded
Thermoplastics: Electrical Properties and Electrostatic Paintability",
IEEE Industry Applications Society, 30th Annual Meeting, October 12,
1995, Orlando, FL, contributed lecture.
2) Helms, J. "Electrostatic Painting of Conductively Modified
Injection Molded Thermoplastics", Coating of Specialty Substrates
(Plastics and Composites) Clinic, SME, Troy, Michigan, June 13, 1995,
Invited paper.
3) Helms, J. Conductive TPOs for Improved Painting Efficiency of
Bumper Fascias", TPOs in Automotive '96 Third International Conference,
October 29, 1996, Novi, Michigan, invited lecture
Terms
Available upon request
Licensee Support
Ford scientist and engineers will assist polymer produces and component
manufacturers in implement electrically conductive polymer materials
in their applications.
Ford Technology Code
M800
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