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) NH 2 —R—NH 2 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.

1 . A semi-aromatic thermoplastic (co)polyimide obtained by polymerization of the following compounds:
 (a) at least one aromatic compound comprising  2  anhydride functional groups and/or its carboxylic acid and/or ester derivatives; and   (b) one or more aliphatic diamines in which said aliphatic diamine or diamines are chosen from the diamines of formula (I) NH 2 —R—NH 2  with R being a saturated aliphatic divalent hydrocarbon radical, the two amine functional groups of which are separated by 4 to 6 carbon atoms and 1 or 2 hydrogen atoms of the divalent radical of which are replaced by 1 or 2 methyl and/or ethyl groups; and optionally the diamines of formula (II) NH 2 —R′—NH 2  with R′ being a saturated or unsaturated and aliphatic, cycloaliphatic or arylaliphatic divalent hydrocarbon radical, which optionally comprises heteroatoms;   or at least one ammonium carboxylate salt obtained from the compounds (a) and (b).   
     
     
         2 . The (co)polyimide as claimed in  claim 1 , wherein the aromatic compound comprising 2 anhydride functional groups and/or its carboxylic acid and/or ester derivatives is selected from the group consisting of: pyromellitic anhydride, 3,3′,4,4′-biphenyltetracarboxylic dianhydride, pyromellitic acid, 3,3′,4,4′-biphenyltetracarboxylic acid and their mixtures. 
     
     
         3 . The (co)polyimide as claimed in  claim 1 , wherein the diamine of formula I is selected from the group consisting of: 2-ethyltetramethylene-1,4-diamine, 2-methylpentamethylene-1,5-diamine or a mixture of these. 
     
     
         4 . The (co)polyimide as claimed in  claim 1 , wherein the diamine of formula I is 2-methylpentamethylene-1,5-diamine. 
     
     
         5 . A process for the manufacture of the (co)polyimide of  claim 1  by solution polymerization of the compounds (a) and (b) or ammonium carboxylate salt obtained from the compounds (a) and (b). 
     
     
         6 . A process for the manufacture of the (co)polyimide of  claim 1  by solid-state polymerization of the compounds (a) and (b) or of the ammonium carboxylate salt obtained from the compounds (a) and (b). 
     
     
         7 . A process for the manufacture of the (co)polyimide of  claim 1  by melt polymerization of the compounds (a) and (b) or of the ammonium carboxylate salt obtained from the compounds (a) and (b). 
     
     
         8 . An ammonium carboxylate salt obtained from
 (a) at least one aromatic compound comprising 2 anhydride functional groups and/or its carboxylic acid and/or ester derivatives; and   (b) one or more aliphatic diamines, in which said aliphatic diamine or diamines are chosen from the diamines of formula (I) NH 2 —R—NH 2  with R being a saturated aliphatic divalent hydrocarbon radical, the two amine functional groups of which are separated by 4 to 6 carbon atoms and 1 or 2 hydrogen atoms of the divalent radical of which are replaced by 1 or 2 methyl and/or ethyl groups; and optionally the diamines of formula (II) NH 2 —R′—NH 2  with R′ being a saturated or unsaturated and aliphatic, cycloaliphatic or arylaliphatic divalent hydrocarbon radical, which optionally comprises heteroatoms.   
     
     
         9 . The salt as claimed in  claim 8 , wherein the salt additionally comprises at least one chain-limiting compound chosen from monoamines, monoacids or diacids in the α,β positions such that they can form an anhydride functional group by a dehydration reaction. 
     
     
         10 . The salt as claimed in  claim 9 , wherein the at least one chain-limiting compound is chosen from: 1-aminopentane, 1-aminohexane, 1-aminoheptane, 1-aminooctane, 1-aminononane, 1-aminodecane, 1-aminoundecane, 1-aminododecane, benzylamine, ortho-phthalic acid, acetic acid, propionic acid, benzoic acid, stearic acid or their mixtures. 
     
     
         11 . A composition comprising the (co)polyimide of  claim 1  and fillers and/or additives. 
     
     
         12 . Solid (co)polyimide particles based on (co)polyimide as claimed in  claim 1 , the median diameter D50 of which is less than or equal to 20 mm, preferably between 2 μm and 10 mm. 
     
     
         13 . A process for the manufacture of a plastic article employing solid (co)polyimide particles as claimed in  claim 12 , by remelting said particles and then shaping an article by extrusion, molding or blow molding of the molten particles. 
     
     
         14 . A plastic article comprising the (co)polyimide of  claim 1 . 
     
     
         15 . The plastic article as claimed in  claim 14 , wherein the article is a molded, extruded or blow-molded part. 
     
     
         16 . The plastic article as claimed in  claim 15 , wherein the article is an injection-molded part, a continuous fiber composite, a film, a fiber, a yarn or a filament. 
     
     
         17 . The plastic article as claimed in  claim 15 , wherein the article is a part woven or knitted from fibers, yarns or filaments based on the (co)polyimide of  claim 1 .