Browse Prior Art Database

Fine Carbon Particles Coated With Polyimide

IP.com Disclosure Number: IPCOM000121197D
Original Publication Date: 1991-Jul-01
Included in the Prior Art Database: 2005-Apr-03
Document File: 1 page(s) / 49K

Publishing Venue

IBM

Related People

Afzali-Ardakani, A: AUTHOR [+3]

Abstract

Disclosed is a material and method of manufacture of carbon particles covered with polyimide to make a high resistivity material as a filler in Teflon (du Pont). Teflon would be a good, low dielectric constant material for packaging if it were more thermally stable with a lower expansion coefficient and less creep. Teflon loaded with glass has problems with voids, vapor transport, adhesion, etc.

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Fine Carbon Particles Coated With Polyimide

      Disclosed is a material and method of manufacture of carbon
particles covered with polyimide to make a high resistivity material
as a filler in Teflon (du Pont).  Teflon would be a good, low
dielectric constant material for packaging if it were more thermally
stable with a lower expansion coefficient and less creep.  Teflon
loaded with glass has problems with voids, vapor transport, adhesion,
etc.

      The standard process for making carbon black can be modified as
shown in the diagram.  Acetylene gas 1 is burned in a gas stream 2
containing insufficient oxygen. Downstream of the acetylene gas
inlet, two streams of vaporized dianhydride 3 (such as PMDA) and
diamine 4 (such as ODA), are added to the stream of carbon particles
5.  The PMDA-ODA condenses on cool surfaces and reacts immediately to
make polyamic acid.  Further downstream, the coated carbon particles
6 pass through an infrared heater 7 to raise the particle temperature
to the imidization temperature, and the cooled, coated carbon
particles can be collected downstream as a non-conducting,
temperature stable powder.

      After the imidization step, the material can be mixed with the
output from a Teflon reactor so that the Teflon coats the polyimide
coated material.  The resulting powder can then be compressed under
heat and pressure to make loaded Teflon.

                            (Image Omitted)

      Disclos...