Thermoplastic polyimides

Patent metadata

Field	Value
Publication number	US-9902809-B2
Application number	US-201214346093-A
Country	US
Kind code	B2
Filing date	Sep 18, 2012
Priority date	Sep 20, 2011
Publication date	Feb 27, 2018
Grant date	Feb 27, 2018

Abstract

The present invention relates to thermoplastic polyimides and to the synthesis thereof. The invention relates in particular to a method for manufacturing semi-aromatic thermoplastic polyimides by means of the solid-state polymerization of a solid ammonium carboxylate salt formed from an aliphatic diamine and an aromatic tetracarboxylic acid, thereby enabling powders having controlled particle sizes to be produced.

First claim

The invention claimed is:

1. A process for producing solid particles of semicrystalline and semiaromatic (co)polyimide, having a median diameter D50 of between 0.01 and 2 mm, said polyimide being thermoplastic and having a melting temperature of between 50 and 350° C., the process comprising:
(a) charging a reactor with a salt formed by reaction of at least one diamine, in which each of the amine functional groups is bound to a respective aliphatic carbon atom, with at least one aromatic tetracarboxylic acid;
(b) polymerizing the salt from step (a) in the solid state to give the (co)polyimide, at an absolute pressure of between 0.005 and 1 MPa and at a temperature T which obeys the following relation:
Tf of the salt from step (a)>T>Tg of the (co)polyimide to be obtained; and

(c) recovering the solid (co)polyimide particles.

2. The process as claimed in claim 1 , wherein the (co)polyimide has a glass transition temperature Tg of less than or equal to 200° C.

3. The process as claimed in claim 1 , wherein the at least one aromatic tetracarboxylic acid is selected from the group consisting of pyromellitic acid, 3,3′,4,4′-biphenyltetracarboxylic acid, 2,3,3′,4′biphenyltetracarboxylic acid, 2,2′,3,3′-biphenyltetracarboxylic acid, 3,3′,4,4′benzophenonetetracarboxylic acid, 2,2′,3,3′-benzophenonetetracarboxylic acid, 1,2,5,6-naphthalenetetracarboxylic acid, 2,3,6,7-naphthalenetetracarboxylic acid, 2,3,5,6-pyridinetetracarboxylic acid, 3,4,9,10-perylenetetracarboxylic acid, 3,3′,4,4′tetraphenylsilanetetracarboxylic acid, and 2,2′-bis(3,4-bicarboxyphenyl) hexafluoropropanetetracarboxylic acid.

4. The process as claimed in claim 1 , wherein the at least one diamine is selected from molecules of formula NH 2 —R—NH 2 with a divalent alkylaromatic or cycloaliphatic, or linear or branched, saturated and/or unsaturated aliphatic hydrocarbon radical R, optionally comprising one or more heteroatoms.

5. The process as claimed in claim 4 , wherein the radical R comprises from 2 to 50 carbon atoms, and optionally one or more heteroatoms.

6. The process as claimed in claim 1 , wherein the at least one diamine is selected from the group consisting of 1,2-diaminoethane, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 2-methyl-1,5-diaminopentane, hexamethylenediamine, 3-methylhexamethylenediamine, 2,5-dimethylhexamethylenediamine, 2,2,4- and 2,4,4-trimethylhexamethylenediamine, 1,7-diaminoheptane, 1,8-diaminooctane, 2,2,7,7-tetramethyloctamethylenediamine, 1,9-diaminononane, 5-methyl-1,9-diaminononane, 1,10-diaminodecane, 1,11-diaminoundecane, 1,12-diaminododecane, 1,13-diaminotridecane, and 1,14-diaminotetradecane.

7. The process as claimed in claim 1 , wherein the at least one diamine is selected from the group consisting of isophoronediamine, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, and diaminodicyclohexylmethane.

8. The process as claimed in claim 1 , wherein the at least one diamine is selected from molecules of formula NH 2 (CH 2 ) n′ -Ph-(CH 2 ) n —NH 2 where n and n′ are nonzero integers which are independent of one and Ph is a phenyl group.

9. The process as claimed in claim 1 , wherein the salt is admixed with an excess of one of the monomers so as to create a stoichiometric imbalance.

10. The process as claimed in claim 1 , wherein the absolute pressure during step (b) is between 0.005 MPa and 0.2 MPa.

11. The process as claimed in claim 1 , wherein the temperature during step (b) is between 50° C. and 250° C.

12. The process as claimed in claim 1 , wherein the number-average molar mass Mn of the (co)polyimide is between 500 g/mol and 50,000 g/mol.

13. Solid particles of (co)polyimide (I), obtained by the process as claimed in claim 1 .

14. Solid particles of semicrystalline and semiaromatic (co)polyimide, having a median diameter D50 of between 0.01 and 2 mm, said polyimide being thermoplastic and having a melting temperature of between 50 and 350° C., said (co)polyimide being obtained from the polymerization of a salt formed by reacting at least one diamine in which each of the amine functional groups is bound to a respective aliphatic carbon atom with at least one aromatic tetracarboxylic acid.

15. A process for producing a composition, the process comprising melt or nonmelt mixing of the solid particles of (co)polyimides (I) as claimed in claim 14 with reinforcing or bulking fillers and/or with impact modifiers and/or with additives.

16. A plastics article, wherein the article comprises the solid particles of (co)polyimide (I) as claimed in claim 14 .

17. The solid particles of claim 14 , wherein the solid particles exhibit less than or equal to a 10% change in relative viscosity after 10 minutes in the melt state, measured with a viscosimeter as a 10 g/L sample in 96% sulfuric acid at a temperature of 25° C.

18. The solid particles of claim 14 , wherein the solid particles exhibit less than or equal to a 10% change in number-average molar mass after 10 minutes in the melt state, determined by 1 H NMR in D 2 SO 4 at 300 K.

19. The process as claimed in claim 1 , wherein the salt formed by reaction of at least one diamine with at least one aromatic tetracarboxylic acid has the general structure shown below:

wherein Ar represents the aromatic group from the aromatic tetracarboxylic acid used in the salt forming reaction and R is dependent on the at least one diamine used in the salt forming reaction.

20. The process as claimed in claim 1 , wherein the salt is formed in a reaction medium comprising a water and alcohol mixture.

21. The process as claimed in claim 1 , wherein the salt is admixed with at least one chain transfer agent.

22. The process as claimed in claim 1 , further comprising:
reacting at least one diamine, in which each of the amine functional groups is bound to a respective aliphatic carbon atom, with at least one aromatic tetracarboxylic acid to produce the salt; and
collecting the produced salt.

Assignees

• Rhodia Operations

Inventors

• Jeol Stephane
• Mollet Vincent
• Paci Benjamin

Classifications

• C08K3/00

  Use of inorganic substances as compounding ingredients · CPC title

• C08L79/08

  Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors · CPC title

• C08G73/101

  containing chain terminating or branching agents · CPC title

• C08G73/1007

  from tetracarboxylic acids or derivatives and diamines · CPC title

• C08G73/10

  Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors · CPC title