Thermoplastic (CO)polyimides and synthesis methods

Abstract

The invention relates to navel thermoplastic (co)polyimides and to the methods of synthesis thereof. The invention specifically relates to semi-aromatic thermoplastic (co)polyimides obtained by polymerisation of at least one aromatic compound comprising two anhydride functions and / or the derivatives thereof, especially carboxylic acid and / or ester, and at least one diamine of formula (I) NH2—R—NH2 wherein R is a saturated aliphatic hydrocarbonated divalent radical, the two amine functions thereof being separated by 4 to 6 carbon atoms, and 1 or 2 hydrogen atoms of the divalent radical being substituted by 1 or 2 methyl and / or ethyl groups. Said (co)polyimides can be transformed into plastic items by various methods such as extrusion, moulding or blowing.

Description

[0001]The present invention relates to novel thermoplastic (co)polyimides and to their processes of synthesis. More specifically, the present invention is targeted at semi-aromatic thermoplastic (co)polyimides obtained by polymerization of at least one aromatic compound comprising two anhydride functional groups and / or its derivatives, in particular carboxylic acid and / or ester derivatives, and at least one specific aliphatic diamine. These (co)polyimides can be converted into plastic articles by various methods, such as extrusion, molding or blow molding.PRIOR ART[0002]Polyimides, in particular aromatic polyimides, are known for their noteworthy thermal and / or mechanical properties which marks them out in particular for high performance applications in various fields, such as aeronautics or also electronics (printed circuit boards, for example).[0003]Nevertheless, these semi-crystalline aromatic polyimides exhibit a number of disadvantages. They are generally infusible, that is to ...

AI Technical Summary

Benefits of technology

[0233]It is possible to obtain composite articles by using the polyimides according to the invention, in particular while carrying out extremely short manufacturing cycles.

Problems solved by technology

Their processing temperatures are generally too high to allow conversion by conventional processes for processing thermoplastic polymers, such as polyamides, in particular extrusion, blow molding or molding.

Furthermore, processing at such temperatures can result in significant decomposition of the polyimide matrix and / or in phenomena of colorations harmful to the production of “attractive” parts.

In addition, their high melting temperatures hinder or prevent the use of some additives, such as organophosphorus flame retardants or natural fibers, which decompose at such temperatures.

Another disadvantage of aromatic polyimides is due to the aromatic diamines, most of which are carcinogens.

In addition, the use of aromatic diamines liable to exhibit carcinogenic effects is not satisfactory.

However, the currently existing semi-aromatic polyimides are not sufficiently effective to compete with the thermoplastic polymers conventionally used in the field of high performance polymers, such as PEEK, having both an M.p. which is high but compatible with the processing equipment and a very high Tg at 150° C., but some of the monomers of which exhibit a high toxicity and / or the processes of synthesis of which can prove to be unsatisfactory in terms of respecting the environment, in particular as a result of the use of toxic monomers.