Method for manufacturing polyimide-based film and polyimide-based film manufactured thereby

Patent metadata

Field	Value
Publication number	US-2020353668-A1
Application number	US-201816762376-A
Country	US
Kind code	A1
Filing date	Dec 4, 2018
Priority date	Dec 4, 2017
Publication date	Nov 12, 2020
Grant date	—

Abstract

The present invention relates to a method for manufacturing a polyimide-based film and a polyimide-based film manufactured thereby and, particularly, to a method for manufacturing a polyimide-based film and a polyimide-based film manufactured thereby, wherein the polyimide-based film is useful as a cover substrate for a flexible electronic device since flexure characteristics thereof, represented by yield elongation, are excellent.

First claim

1 . A method of manufacturing a polyimide-based film in a roll-to-roll manner comprising:
conducting first heat treatment (S1) on a polyimide-based film obtained as a gel state formed by being cast on a support while elongating the polyimide-based film at an elongation percentage of not less than 100% and less than 135% in a machine direction (MD) and shrinking the polyimide-based film at a shrinkage percentage of more than 75% and not more than 100% in a transverse direction (TD) (except in the case where the elongation percentage in the machine direction is equal to the shrinkage percentage in the transverse direction); and conducting second heat treatment (S2) on the first heat-treated polyimide-based film while further elongating the polyimide-based film in the machine direction (MD) at a tension not less than 30 N/mm 2 and less than 160 N/mm 2 , wherein a maximum heating temperature during the first heat treatment is 250° C. to 330° C., and the second heat treatment is performed for 200 seconds or longer at a temperature within −10° C. to +30° C. of the maximum heating temperature reached during the first heat treatment.

2 . The method according to claim 1 , wherein, in step (S1), the elongation percentage in the machine direction is 105% to 130%.

3 . The method according to claim 1 , wherein, in step (S1), the elongation percentage in the machine direction is 115% to 130%.

4 . The method according to claim 1 , wherein, in step (S1), the shrinkage percentage in the traverse direction is 80% to 100%.

5 . The method according to claim 4 , wherein, in step (S1), the shrinkage percentage in the transverse direction is 80% to 95%.

6 . The method according to claim 1 , wherein, in step (S2), the time for second heat treatment is not less than 200 seconds and less than 1,500 seconds.

7 . The method according to claim 1 , wherein, in step (S2), the tension is 30 N/mm 2 to 150 N/mm 2 .

8 . A polyimide-based film manufactured according to the method according to claim 1 .

9 . The polyimide-based film according to claim 8 , wherein the polyimide-based film has a yield strain in a uniaxial direction of 3% or more.

10 . The polyimide-based film according to claim 9 , wherein the polyimide-based film has a pencil hardness of 1H or more based on ASTM D3363 measurement, and a yellowness of 5.0 or less and a light transmittance of 85% or more at 550 nm based on measurement with a CM-3700D produced by Konica Minolta, Inc.

Assignees

• Kolon Inc

Inventors

• Hong Ki Ii
• Jung Hak-Gee

Classifications

• B29K2995/0051

  mono-axially · CPC title

• B29K2079/08

  PI, i.e. polyimides or derivatives thereof · CPC title

• C08J2379/08

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

• B29C55/143 Primary

  firstly parallel to the direction of feed and then transversely thereto · CPC title

• B29C71/02

  Thermal after-treatment {(B29C71/0063 and B29C71/0072 take precedence)} · CPC title