Polyamide production method

Patent metadata

Field	Value
Publication number	US-9840587-B2
Application number	US-201314437523-A
Country	US
Kind code	B2
Filing date	Oct 23, 2013
Priority date	Oct 23, 2012
Publication date	Dec 12, 2017
Grant date	Dec 12, 2017

Abstract

The polyamide production method of the present invention comprises the steps of: producing a low-order condensate by effecting a polycondensation reaction between a dicarboxylic acid component containing between about 5 and about 40 mol. % of terephthalic acid, and a diamine component containing between about 70 and about 100 mol. % of a xylylenediamine in which the content of paraxylylenediamine is between about 50 and about 100 mol. %, under conditions of a reaction temperature of at least about 200° C. and less than about 230° C.; discharging and cooling the low-order condensate at a pressure at or below atmospheric pressure, in an inert gas atmosphere; and subjecting the discharged and cooled low-order condensate to solid state polymerization. The production method makes it possible to obtain a polyamide having outstanding mechanical strength, heat resistance, color tone and the like without problems such as gelling.

First claim

The invention claimed is:

1. A polyamide production method comprising:
preparing a low-order condensate through polycondensation of a dicarboxylic acid component containing about 5 mol % to about 40 mol % of terephthalic acid and a diamine component comprising about 50 mol % to about 70 mol % of p-xylylenediamine and about 30 mol % to about 50 mol % of m-xylylenediamine at a reaction temperature of about 200° C. to less than about 230° C. after adding both the dicarboxylic acid component and the diamine component to a reactor;
discharging and cooling the low-order condensate at atmospheric pressure or less under an inert gas atmosphere; and
solid-polymerizing the discharged and cooled low-order condensate,
wherein the polycondensation is performed in the presence of an end-capping agent.

2. The polyamide production method according to claim 1 , wherein preparing the low-order condensate is performed under conditions of a reaction pressure of about 0.5 MPa to about 3 MPa, a reaction time of about 0.5 hours to about 4 hours, and a moisture content of about 15 wt % to about 35 wt % in a reaction system upon completion of reaction, and the discharged and cooled low-order condensate has an inherent viscosity of about 0.07 dL/g to about 0.40 dL/g, as measured at a concentration of about 0.5 g/dL and at a temperature of about 25° C. in concentrated sulfuric acid.

3. The polyamide production method according to claim 1 , wherein the solid polymerization is performed at a maximum reaction temperature of about 170° C. to about 210° C.

4. The polyamide production method according to claim 1 , wherein the polyamide has a melting point of about 280° C. or more and a glass transition temperature of about 100° C. or more.

5. The polyamide production method according to claim 1 , further comprising:
an enrichment process before preparation of the low-order condensate.

6. The polyamide production method according to claim 1 , wherein the step of preparing a low-order condensate takes place in an aqueous solution.

Assignees

• Cheil Ind Inc
• Lotte Advanced Mat Co Ltd

Inventors

• Kanda Tomomich
• Shimoda Tomoaki

Classifications

• C08G69/265

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

• C08G69/46

  Post-polymerisation treatment · CPC title

• C08G69/26

  derived from polyamines and polycarboxylic acids · CPC title

• C08G69/30 Primary

  Solid state polycondensation · CPC title

• C08G69/28

  Preparatory processes · CPC title