Process for preparing a poly(amide-imide) film and a poly(amide-imide) film prepared by the same

Patent metadata

Field	Value
Publication number	US-2019202990-A1
Application number	US-201816213064-A
Country	US
Kind code	A1
Filing date	Dec 7, 2018
Priority date	Dec 28, 2017
Publication date	Jul 4, 2019
Grant date	—

Abstract

Embodiments relate to a process for preparing a poly(amide-imide) film and a poly(amide-imide) film prepared thereby. The process is capable of preparing a poly(amide-imide) film that is excellent in optical properties and mechanical properties.

First claim

1 . A process for preparing a poly(amide-imide) film, which comprises:
simultaneously or sequentially mixing and reacting a diamine compound, a dianhydride compound, and a dicarbonyl compound in an organic solvent in a polymerization apparatus to prepare a polymer solution; transferring the polymer solution to a tank; purging the tank with an inert gas; casting the polymer solution in the tank onto a belt and then drying it to prepare a gel-sheet; thermally treating the gel-sheet while it is moved to prepare a cured film; cooling the cured film while it is moved; and winding the cooled cured film using a winder.

2 . The process for preparing a poly(amide-imide) film of claim 1 ,
wherein the step of preparing the polymer solution may comprise (a) simultaneously or sequentially mixing and reacting a diamine compound, a dianhydride compound, and a dicarbonyl compound in an organic solvent to prepare a first polymer solution; (b) measuring the viscosity of the first polymer solution and evaluating whether the target viscosity is reached; and (c) if the viscosity of the first polymer solution does not reach the target viscosity, further adding the dicarbonyl compound to prepare a second polymer solution having the target viscosity.

3 . The process for preparing a poly(amide-imide) film of claim 2 ,
wherein the target viscosity is 100,000 cps to 300,000 cps at room temperature.

4 . The process for preparing a poly(amide-imide) film of claim 1 ,
which further comprises the step of purging the tank with an inert gas in the step of preparing the polymer solution.

5 . The process for preparing a poly(amide-imide) film of claim 1 ,
wherein, once the polymer solution is prepared, the step of transferring the polymer solution to the tank is carried out without any additional steps.

6 . The process for preparing a poly(amide-imide) film of claim 1 ,
wherein the internal temperature of the tank is −20° C. to 20° C.

7 . The process for preparing a poly(amide-imide) film of claim 1 ,
which further comprises carrying out vacuum degassing after the polymer solution is transferred to the tank.

8 . The heat-resistant resin composition of claim 7 ,
wherein the vacuum degassing is carried out for 30 minutes to 3 hours after depressurizing the internal pressure of the tank to 0.1 to 0.7 bar.

9 . The process for preparing a poly(amide-imide) film of claim 1 ,
wherein the purging is carried out by purging the tank with an inert gas at an internal pressure of 1 atm to 2 atm.

10 . The process for preparing a poly(amide-imide) film of claim 1 ,
which further comprise storing the polymer solution in the tank for 12 hours to 360 hours after the purging step.

11 . The process for preparing a poly(amide-imide) film of claim 1 ,
wherein the polymer solution is cast and then dried at a temperature of 60° C. to 150° C. for 5 minutes to 60 minutes to prepare a gel-sheet.

12 . The process for preparing a poly(amide-imide) film of claim 1 ,
wherein the thermal treatment is carried out in a temperature range of 80° C. to 500° C. at a temperature elevation rate of 2° C./min to 80° C./min for 5 to 40 minutes.

13 . The process for preparing a poly(amide-imide) film of claim 12 ,
wherein the initial temperature of the thermal treatment of the gel-sheet is 80° C. or higher, and the maximum temperature in the thermal treatment is 300° C. to 500° C.

14 . The process for preparing a poly(amide-imide) film of claim 1 ,
wherein the step of cooling the cured film while it is moved comprises a first temperature lowering step of reducing the temperature at a rate of 100° C./min to 1,000° C./min, and a second temperature lowering step of reducing the temperature at a rate of 40° C./min to 400° C./min; the second temperature lowering step is performed after the first temperature lowering step; and the temperature lowering rate of the first temperature lowering step is faster than the temperature lowering rate of the second temperature lowering step.

15 . The process for preparing a poly(amide-imide) film of claim 1 ,
wherein the ratio of the moving speed of the gel-sheet on the belt at the time of drying to the moving speed of the cured film at the time of winding is 1:0.95 to 1:1.40.

16 . The process for preparing a poly(amide-imide) film of claim 1 ,
wherein the thickness variation (%) according to the following Equation 1 is 3% to 30%:
Thickness variation (%)=( M 1− M 2)/ M 2×100  [Equation 1]

in the above Equation 1, M1 is the thickness (μm) of the gel-sheet, and M2 is the thickness (μm) of the cooled cured film at the time of winding.

17 . A poly(amide-imide) film prepared by the preparation process of claim 1 .

Assignees

• Skc Co Ltd

Inventors

• Kim Sunhwan
• Oh Dae Seong
• Lee Jin Woo
• Jeong Dawoo
• Lim Dong Jin
• Choi Kyung Won

Classifications

• C08G73/1039

  comprising halogen-containing substituents · CPC title

• C08G73/1067 Primary

  Wholly aromatic polyimides, i.e. having both tetracarboxylic and diamino moieties aromatically bound · CPC title

• C08J5/18

  Manufacture of films or sheets · CPC title

• C08J2379/08

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

• B29C41/46

  Heating or cooling · CPC title