Production of polyamides by polycondensation

Patent metadata

Field	Value
Publication number	US-9534083-B2
Application number	US-201314016520-A
Country	US
Kind code	B2
Filing date	Sep 3, 2013
Priority date	Sep 3, 2012
Publication date	Jan 3, 2017
Grant date	Jan 3, 2017

Abstract

In a process for producing polyamides by polycondensation of polycondensable polyamide-forming monomers and/or oligomers in reaction mixtures comprising same, which may be water-containing but are free from organic solvents, the polycondensation is effected in an agitated reactor under agitation in a first step in the liquid phase and after a phase change taking place during the process in the same reactor is effected in a subsequent second step in the solid state, wherein the temperature in the reactor is below the melting point of the polyamide in the second step at least.

First claim

We claim:

1. A process for producing a polyamide by polycondensation of polycondensable polyamide forming monomers and/or oligomers in reaction mixtures comprising same, which are free from organic solvents, wherein the polycondensation is effected in an agitated reactor under agitation in a first step in the liquid phase and after a phase change taking place during the process in the same reactor is effected in a subsequent second step in the solid state, wherein the temperature in the reactor is below the melting point of the polyamide in the second step,
wherein the polycondensation is conducted at a pressure of not more than 10 bar, and
wherein the polycondensable monomers and/or oligomers are present at the start of the polycondensation in a weight ratio to water ranging from 1.2:1 to 1.7:1.

2. The process according to claim 1 wherein the temperature in the reactor is above the glass transition point of the polyamide in the second step.

3. The process according to claim 1 wherein the polyamide has a melting point of at least 260° C.

4. The process according to claim 1 wherein no solid-state polycondensation is effected before the polycondensation in the first step.

5. The process according to claim 1 wherein the maximum temperature in the reactor is at least 25° C. below the melting point of the polyamide in the second step.

6. The process according to claim 5 wherein the maximum temperature in the reactor is at least 30° C. below the melting point of the polyamide in the second step.

7. The process according to claim 5 wherein the maximum temperature in the reactor is at least 35° C. below the melting point of the polyamide in the second step.

8. The process according to claim 1 wherein the polycondensation is conducted at a pressure of not more than 7 bar.

9. The process according to claim 1 wherein the polycondensation is conducted at a pressure of not more than 5.5 bar.

10. The process according to claim 1 wherein the temperature in the reactor rises continuously and/or incrementally in the course of the polycondensation up to the phase change.

11. The process according to claim 1 wherein low-boiling compounds formed in the course of the condensation and/or water are separated off in gaseous form during the first and/or second step of the polycondensation.

12. The process according to claim 1 wherein the second step is followed by a postcondensation at ambient pressure, preferably under flushing with an inert gas.

13. A polyamide obtained by the process according to claim 1 .

14. The polyamide according to claim 13 in the shape of fibers, self-supporting film/sheet or shaped articles.

Assignees

• Basf Se

Inventors

• Stammer Achim
• El-Toufaili Faissal-Ali
• Gramlich Simon
• Ulzhöfer Angela

Classifications

• C08G69/30 Primary

  Solid state polycondensation · CPC title

• C08G69/06

  Solid state polycondensation · CPC title

• C08G69/32

  from aromatic diamines and aromatic dicarboxylic acids with both amino and carboxylic groups aromatically bound · CPC title

• C08G69/42 Primary

  Polyamides containing atoms other than carbon, hydrogen, oxygen, and nitrogen (C08G69/12, C08G69/32 take precedence) · CPC title

• C08L77/06

  Polyamides derived from polyamines and polycarboxylic acids (C08L77/10 takes precedence) · CPC title