TITLE: Process for production of aromatic polyimide film.
European Patent Application EP0087305 A2

ABSTRACT:
Abstract not available for EP0087305
Abstract of corresponding document: US4470944
The present invention relates to a process for producing an of aromatic
polyimide film comprising (A) casting on a support a dope containing an
amide-type polar solvent and 10-45 weight percent of a polyamic acid
having more than 0.4 dl/g an inherent viscosity of more than 0.4 dl/g,
(B) concentrating the polymer content to be at least higher than that
of the initial dope while simultaneously raising the ring closure ratio
above 30%, (C) removing the solvent from the film by extraction in an
aqueous medium so as to lower the solvent content of the film below 10%
and (D) then heating the film to a temperature of more than 200 DEG C.
The process of the present invention is useful for the production of
aromatic polyimide film having a reduced rate of solvent decomposition
and improved productivity. The aromatic polyimide film produced by the
process of the present invention is superior in thermal as well as
mechanical properties and is highly useful as an electric insulation
material and also as a base for flexible printed circuits, magnetic
tape, etc.

INVENTORS:
Asakura, Toshiyuki
Mizouchi, Masanori
Kobayashi, Hiroaki

APPLICATION NUMBER: EP19830300886
PUBLICATION DATE: 08/31/1983
FILING DATE: 02/21/1983

ASSIGNEE: TORAY INDUSTRIES (JP)
INTERNATIONAL CLASSES: B29C47/00; B05D5/12; B29B7/00; B29C31/00; B29C39/00; B29C41/12;
B29D7/01; C08J5/18; B29K79/00; H05K1/03; H05K3/02; (IPC1-7): C08J5/18
EUROPEAN CLASSES: B05D5/12+B; C08J5/18+L79/08

FOREIGN REFERENCES:
3961009 Process for the production of a shaped article of a heat
  resistant polymer
GB1155541A
GB903272A
GB2070509A