Process for the continuous preparation of an aliphatic or partially aromatic polyamide

Patent metadata

Field	Value
Publication number	US-9994678-B2
Application number	US-201414896945-A
Country	US
Kind code	B2
Filing date	Jun 11, 2014
Priority date	Jun 12, 2013
Publication date	Jun 12, 2018
Grant date	Jun 12, 2018

Abstract

The present invention relates to a process for the preparation of an aliphatic or partially aromatic polyamide, in which an aqueous composition of the monomers is subjected to an oligomerization at elevated temperature and increased pressure, the reaction mixture is optionally subjected to a first decompression to reduce the water content, the (optionally decompressed) reaction mixture is heated within a short time to a temperature above the melting temperature of the polyamides and the heated reaction mixture is subjected to a (further) decompression to reduce the water content and to an after-polymerization.

First claim

The invention claimed is:

1. A process for continuously preparing an aliphatic or semiaromatic polyamide, comprising
a) providing an aqueous composition comprising at least one component which is suitable for polyamide formation and is selected from the group consisting of dicarboxylic acids, diamines, salts of at least one dicarboxylic acid and at least one diamine, lactams, ω-amino acids, aminocarbonitriles, and mixtures thereof, and supplying the composition provided to an oligomerization zone,
b) in the oligomerization zone, subjecting the composition to an oligomerization at a temperature of 170 to 290° C. and an absolute pressure of at least 20 bar, the oligomerization in step b) being effected without mass transfer with the environment, and a liquid output comprising polyamide oligomers is withdrawn from the oligomerization zone,
c) optionally feeding the output from the oligomerization zone into a flash zone E1) and subjecting the output to expansion to obtain a water-containing gas phase and a liquid phase comprising the polyamide oligomers, and at least a portion of the water-containing gas phase is removed,
d) subjecting the liquid output from the oligomerization zone or the liquid phase from the flash zone E1) to rapid heating to a temperature above a melting temperature Tm 2 of the aliphatic or semiaromatic polyamide, and
e) feeding the heated composition from step d) into a flash zone E2) and expanding the heated composition to obtain a water-containing gas phase and a polyamide-containing liquid phase, removing at least a portion of the water-containing gas phase and subjecting the polyamide-containing phase to a postpolymerization at a temperature above the melting temperature Tm 2 of the aliphatic or semiaromatic polyamide.

2. The process according to claim 1 , wherein the composition provided in step a) has a water content of 20 to 55% by weight, based on the total weight of the composition.

3. The process according to claim 1 , wherein the polyamide is selected from the group consisting of PA 6.T, PA 9.T, PA8.T, PA 10.T, PA 12.T, PA 6.I, PA 8.I, PA 9.I, PA 10.I, PA 12.I, PA 6.T/6, PA 6.T/10, PA 6.T/12, PA 6.T/6.I, PA6.T/8.T, PA 6.T/9.T, PA 6.T/10T, PA 6.T/12.T, PA 12.T/6.T, PA 6.T/6.I/6, PA 6.T/6.I/12, PA 6.T/6.I/6.10, PA 6.T/6.I/6.12, PA 6.T/6.6, PA 6.T/6.10, PA 6.T/6.12, PA 10.T/6, PA 10.T/11, PA 10.T/12,PA 8.T/6.T, PA 8.T/66, PA 8.T/8.I, PA 8.T/8.6, PA 8.T/6.I, PA 10.T/6.T, PA 10.T/6.6, PA 10.T/10.I, PA 10T/10.I/6.T, PA 10.T/6.I, PA 4.T/4.I/46, PA 4.T/4.I/6.6, PA 5.T/5.I, PA 5.T/5.I/5.6, PA 5.T/5.I/6.6, PA 6.T/6.I/6.6, PA MXDA.6, PA IPDA.I, PA IPDA.T, PA MACM.I, PA MACM.T, PA PACM.I, PA PACM.T, PA MXDA.I, PA MXDA.T, PA 6.T/IPDA.T, PA 6.T/MACM.T, PA 6.T/PACM.T, PA 6.T/MXDA.T, PA 6.T/6.I/8.T/8.I, PA 6.T/6.I/10.T/10.I, PA 6.T/6.I/IPDA.T/IPDA.I, PA 6.I/6.I/MXDA.T/MXDA.I, PA 6.T/6.I/MACM.T/MACM.I, PA 6.T/6.I/PACM.T/PACM.I, PA 6.T/10.T/IPDA.T, PA 6.T/12.T/IPDA.T, PA 6.T/10.T/PACM.T, PA 6.T/12.T/PACM.T, PA 10.T/IPDA.T, PA 12.T/IPDA.T, and copolymers and mixtures thereof.

4. The process according to claim 1 , wherein the polyamide oligomer is selected from the group consisting of PA 4, PA 5, PA 6, PA 7, PA 8, PA 9, PA 10, PA 11, PA 12, PA 46, PA 66, PA 666, PA 69, PA 610, PA 612, PA 96, PA 99, PA 910, PA 912, PA 1212 and copolymers and mixtures thereof.

5. The process according to claim 1 , wherein the oligomerization zone used for oligomerization comprises at least one tubular reactor.

6. The process according to claim 1 , wherein the oligomerization zone used for oligomerization is not backmixed.

7. The process according to claim 1 , wherein the oligomerization in step b) is effected monophasically in the liquid phase.

8. The process according to claim 1 , wherein the temperature in the oligomerization zone in step b) is within a range from 200 to 290° C.

9. The process according to claim 1 , wherein the absolute pressure in the oligomerization zone in step b) is within a range from 20 to 100 bar.

10. The process according to claim 1 , wherein in step b), a residence time of the composition supplied in the oligomerization zone is within a range from 10 minutes to 6 hours.

11. The process according to claim 1 , wherein the output from the oligomerization zone is expanded in step c) to an absolute pressure at least 5 bar below the pressure in the oligomerization zone.

12. The process according to claim 1 , wherein the absolute pressure in the flash zone E1) in step c) is within a range from 10 to 50 bar.

13. The process according to claim 1 , wherein the temperature in the flash zone E1) in step c) is within a range from 170 to 290° C.

14. The process according to claim 1 , wherein the liquid phase obtained in step c) from the flash zone E1) has a water content of 10 to 30% by weight, based on the total weight of the liquid phase.

15. The process according to claim 1 , in which no solid phase comprising polyamide oligomers is obtained in step c).

16. The process according to claim 1 , wherein, if the output from the oligomerization zone is not subjected to any expansion in step c), the pressure is reduced before the rapid heating in step d).

17. The process according to claim 1 , wherein the heating to a temperature above the melting temperature Tm 2 of the aliphatic or semiaromatic polyamide is effected in step d) within not more than 5 minutes.

18. The process according to claim 1 , wherein the liquid output from the oligomerization zone or the liquid phase from the flash zone E1) is heated in step d) to a temperature of at least 310° C.

19. The process according to claim 1 , wherein the rapid heating in step d) is effected with a heat exchanger.

20. The process according to claim 1 , wherein the absolute pressure of the heated reaction mixture is reduced in step d) to a pressure of less than 35 bar.

21. The process according to claim 1 , wherein the absolute pressure in the flash zone E2) is within a range from 2 to 15 bar.

22. The process according to claim 1 , wherein the temperature in the flash zone E2) in step e) is at least 5° C. above the melting temperature Tm 2 of the aliphatic or semiaromatic polyamide and no solid phase comprising polyamide oligomers is obtained.

23. The process according to claim 1 , wherein the residence time in the flash zone E2) for aliphatic polyamides in step e) is 1 minute to 60 minutes.

24. The process according to claim 1 , wherein the residence time in the flash zone E2) for semiaromatic polyamides in step e) is 30 seconds to 15 minutes.

25. The process according to claim 1 , wherein the flash zone E2) comprises at least one apparatus selected from unstirred or stirred flash tanks, strand devolatilizers, extruders, kneaders, other apparatuses having kneading and/or conveying elements, and combinations thereof.

26. The process according to claim 1 , wherein the polyamides present in the output of the postpolymerization in step e) from the flash zone E2) have a number-average molecular weight M n in the range from 12,000 to 22,000 g/mol.

27. The process according to claim 1 , wherein the polyamides present in the output of the postpolymerization in step e) from the flash zone E2) have a polydispersity PD of not more than 4.5.

28. The process according to claim 1 , wherein the water phase obtained in step c) and/or that obtained in step e) is used at least partly for preparation of the aqueous composition in ste

Assignees

• Basf Se

Inventors

• Schmidt Christian
• Clauss Joachim
• Wilms Axel
• Rauschenberger Volker
• Kory Gad
• Schwiegk Stefan
• Schneller Arnold
• Stammer Achim
• Niedermaier Frank
• Hackel Bernd

Classifications

• C08G69/265

  from at least two different diamines or at least two different dicarboxylic acids · CPC title

• C08G69/26

  derived from polyamines and polycarboxylic acids · CPC title

• C08G69/28 Primary

  Preparatory processes · CPC title