Polyimide film for graphite sheet, and graphite sheet manufactured therefrom

Patent metadata

Field	Value
Publication number	US-12428526-B2
Application number	US-202017772299-A
Country	US
Kind code	B2
Filing date	Sep 15, 2020
Priority date	Oct 28, 2019
Publication date	Sep 30, 2025
Grant date	Sep 30, 2025

Abstract

Disclosed herein are a polyimide film for graphite sheets and a graphite sheet manufactured using the same. The polyimide film is fabricated by imidizing a precursor composition including: a polyamic acid prepared by reacting a dianhydride monomer with a diamine monomer; and an organic solvent, wherein the diamine monomer includes about 30 mol % to about 70 mol % of 4,4′-methylenedianiline and about 30 mol % to about 70 mol % of 4,4′-oxydianiline based on the total number of moles of the diamine monomer, 4,4′-methylenedianiline and 4,4′-oxydianiline being present in total in an amount of about 85 mol % or more based on the total number of moles of the diamine monomer.

First claim

The invention claimed is:

1. A polyimide film for graphite sheets, the polyimide film being fabricated by imidizing a precursor composition comprising: a polyamic acid prepared by reacting a dianhydride monomer with a diamine monomer; and an organic solvent,
wherein the diamine monomer comprises about 30 mol % to about 70 mol % of 4,4′-methylenedianiline and about 30 mol % to about 70 mol % of 4,4′-oxydianiline based on the total number of moles of the diamine monomer, 4,4′-methylenedianiline and 4,4′-oxydianiline being present in total in an amount of about 85 mol % or more based on the total number of moles of the diamine monomer,
wherein the precursor composition comprises a sublimable inorganic filler,
wherein the sublimable inorganic filler is dicalcium phosphate,
wherein the sublimable inorganic filler is present in an amount of 0.2 parts by weight to 0.5 parts by weight relative to 100 parts by weight of the polyamic acid, and
wherein an average particle diameter (D 50 ) of the sublimable inorganic filler is 1.5 μm to 4.5 μm.

2. The polyimide film according to claim 1 , wherein the dianhydride monomer comprises at least one selected from the group of pyromellitic dianhydride, 3,3′,4,4′-biphenyltetracarboxylic dianhydride, 2,3,3′,4-biphenyltetracarboxylic dianhydride, oxydiphthalic anhydride, 3,3′,4,4′-diphenylsulfonetetracarboxylic dianhydride, and 3,3′,4,4′-benzophenonetetracarboxylic dianhydride.

3. The polyimide film according to claim 1 , wherein the polyamic acid is present in an amount of about 10 wt % to about 30 wt % based on the total weight of the precursor composition.

4. The polyimide film according to claim 1 , wherein the precursor composition has a viscosity of about 100,000 cP to about 300,000 cP at a temperature of 23° C. and a shear rate of 1 sec −1 .

Assignees

• Pi Advanced Mat Co Ltd

Inventors

• Son Won Ho
• Jo Hyong Sop

Classifications

• C04B35/6306

  Binders based on phosphoric acids or phosphates · CPC title

• C04B35/6267

  Pyrolysis, carbonisation or auto-combustion reactions · CPC title

• C04B35/63444

  Nitrogen-containing polymers, e.g. polyacrylamides, polyacrylonitriles, polyvinylpyrrolidone [PVP], polyethylenimine [PEI] · CPC title

• C04B35/524 Primary

  obtained from polymer precursors, e.g. glass-like carbon material · CPC title

• C08G73/1071

  Wholly aromatic polyimides containing oxygen in the form of ether bonds in the main chain · CPC title