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Polyimide film for flexible display device substrate

A flexible display device, polyimide film technology, applied in nonlinear optics, instruments, coatings, etc.

Active Publication Date: 2019-11-22
LG CHEM LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] The present invention aims to solve the technical problems in the related art, and therefore, an aspect of the present invention is to provide a polyimide film with improved transparency that does not cause shrinkage even in a high temperature process

Method used

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  • Polyimide film for flexible display device substrate
  • Polyimide film for flexible display device substrate

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0073] polymerization of BPDA-pPDA / PA (98.9:100:2.2) polyimide

[0074] 100 g of N-methyl-2-pyrrolidone (NMP) was charged into a reactor subjected to nitrogen flow, and 6.192 g (57.259 mmol) of p-phenylenediamine (p-PDA) were dissolved while maintaining the temperature of the reactor at 25° C. ). Add 16.661g (56.629mmol) 3,3',4,4'-biphenylcarboxylic dianhydride (s-BPDA) and 56.96g NMP to the p-PDA solution at the same temperature, and stir for a predetermined period Dissolved over time to obtain polyamic acid. To the polyamic acid solution obtained above, 0.187 g (1.260 mmol) of phthalic anhydride (PA) was added and stirred for a predetermined period of time, thereby obtaining a polyimide precursor.

[0075] An organic solvent was added to the polyimide precursor obtained above so that the solid content thereof would be 12.8% by weight to prepare a polyimide precursor solution.

[0076] Spin-coat the polyimide precursor solution onto a glass substrate. The glass substrate ...

experiment example 1

[0090] The CTE, thermal decomposition temperature, mechanical properties, and transparency of the polyimide films prepared above were measured by the following methods, and the results are shown in Table 1.

[0091]

[0092] Each of the polyimide films prepared in Examples and Comparative Examples was cut into a size of 5 mm×16 mm, and the samples were loaded in a Q400 device of TA Company using an accessory. The actual measured length of the film was 16mm, and the force to stretch the film was set at 0.02N. A first heating process was performed at a heating rate of 5°C / min in a temperature range from room temperature to 450°C, and then a cooling process was performed to 50°C at a cooling rate of 5°C / min. Then, when the cooled sample was heated at a rate of 5°C / minute in the temperature range of 50°C to 450°C, the change in thermal expansion was measured with TMA. The thermal expansion coefficients in the range of 100°C to 350°C and in the range of 350°C to 450°C and furthe...

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Abstract

A polyimide film according to the present invention can be effectively used as a substrate for a flexible display device without a deterioration in heat resistance even at a temperature of 350 DEG C or higher since a coefficient of thermal expansion (A) in the section of 100-350 DEG C, of the polyimide film, and a coefficient of thermal expansion (B) in the section of 350-450 DEG C, of the polyimide film, meet 0<B / A<2.

Description

technical field [0001] This application claims the benefit of priority of Korean Patent Application No. 10-2017-0112323 filed on September 4, 2017 and Korean Patent Application No. 10-2017-0172005 filed on December 14, 2017, all of which The disclosure is incorporated herein by reference. [0002] The present invention relates to a polyimide film having low residual stress and improved transparency for a substrate of a flexible display device and a method for preparing the same. Background technique [0003] Polyimide (PI) is a polymer with relatively low crystallinity or substantially amorphous structure, and it has advantages such as the following: simple synthesis process, easy processing into thin films, no need for curing Cross-linked moieties, and have excellent polymer properties such as transparency, heat and chemical resistance, mechanical and electrical properties, and dimensional stability due to its rigid chain structure. Polyimides are now widely used as elect...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08J5/18C08L79/08C08G73/10G02F1/1333
CPCC08J5/18C08G73/1014C08G73/1067C09D179/08C08J2379/08G02F1/133305G02F1/133723C08L79/08C08L2201/10C08L2203/16C08L2203/20
Inventor 郑惠元朴灿晓李珍昊朴珍永金炅焕洪叡智催丹碧
Owner LG CHEM LTD
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