Method for manufacturing polyimide-based film and polyimide-based film manufacture

Patent metadata

Field	Value
Publication number	US-2023226745-A1
Application number	US-202318153388-A
Country	US
Kind code	A1
Filing date	Jan 12, 2023
Priority date	Dec 4, 2018
Publication date	Jul 20, 2023
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 polyimide-based film manufactured by a roll-to-roll manner, the roll-to-roll manner comprising:
conducting first heat treatment (S 1 ) 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 more 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 less than 100% in a transverse direction (TD); and conducting second heat treatment (S 2 ) 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 polyimide-based film according to claim 1 , wherein, in step (S 1 ), the elongation percentage in the machine direction is 105% to 130%.

3 . The polyimide-based film according to claim 1 , wherein, in step (S 1 ), the elongation percentage in the machine direction is 115% to 130%.

4 . The polyimide-based film according to claim 1 , wherein, in step (S 1 ), the shrinkage percentage in the traverse direction is 80% to 100%.

5 . The polyimide-based film according to claim 4 , wherein, in step (S 1 ), the shrinkage percentage in the transverse direction is 80% to 95%.

6 . The polyimide-based film according to claim 1 , wherein, in step (S 2 ), the time for second heat treatment is not less than 200 seconds and less than 1,500 seconds.

7 . The polyimide-based film according to claim 1 , wherein, in step (S 2 ), the tension is 30 N/mm 2 to 150 N/mm 2 .

8 . The polyimide-based film according to claim 1 , wherein the polyimide-based film has a yield strain in a uniaxial direction of 3% or more.

9 . The polyimide-based film according to claim 1 , 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.

10 . A polyimide-based film having a yield strain in a uniaxial direction of 3% or more, 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

• B32B2307/536

  Hardness · CPC title

• B32B27/281

  comprising polyimides · CPC title

• B32B2307/54

  Yield strength; Tensile strength · CPC title

• B32B2307/412

  Transparent · CPC title

• B32B2457/20

  Displays, e.g. liquid crystal displays, plasma displays · CPC title