The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 09, 1992
Filed:
Jan. 31, 1990
Applicant:
Inventors:
Assignee:
Lenzing AG, Lenzing, AT;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C08G / ;
U.S. Cl.
CPC ...
528 57 ; 528 51 ; 528 52 ; 528 73 ; 528223 ; 528224 ; 528229 ; 528350 ; 528351 ; 528353 ; 26433116 ;
Abstract
To produce flame-retardant thermostable new homopolyimides having structural units of the general formula ##STR1## by reacting 3,3',4,4'-benzophenone tetracarboxylic acid dianhydride with an overall equimolar amount of 2,4- and/or 2,6-toluene diisocyanate, the reaction is carried out in the presence of a polymerization accelerator. The new homopolyimides have a glass transition point of at least 320.degree. C. and are processible to moulded articles exhibiting a similarly good structural strength as could hitherto be observed in mixed polyimides only. Furthermore, the new homopolyimides can be spun to fibres.