There are several things to consider when looking at these two types of
materials.

For one they are very different as far as the Tg is concerned.  The higher Tg
epoxies typically have a Tg of only 175 C while Polyimides are up around 260 C.
(a big difference)  your specific application would have a great deal to do with
this.

There is a significant difference in price between these materials, again your
application will tell you if you can justify the cost difference.

The process time and steps (oxide coating) press time etc. involved and handling
requirements are different for these materials.  The polyimide requires longer
press times and or post cures and tend to be more brittle than the epoxies.  You
also have to be careful about your oxide coating more so on Polyimide than the
epoxy.

These are just a few of the more significant differences in these materials.
You need to look at your specific application to make a decision.  I would also
suggest you contact one or more of the laminate suppliers who deal with these
materials every day.  There are several out there. They can give you more
information on which way you should go.  Good luck.


The opinions and views expressed in this message are my own.  They do not
reflect or represent that of my employer.
____________________Reply Separator____________________
Subject:    [TN] Epoxy vs Polyimide  data
Author: [log in to unmask]>          Ken Lee <[log in to unmask]
Date:       3/20/99 2:50 PM

                I am looking for data comparing polyimide to FR4,
particularly the newer high Tg epoxy materials (GFG). I would appreciate any
info or leads.

                Ken Lee

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