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US 2018/0294456 A1Published application
Microporous Polyimide Film and Process for Producing the Same
AssigneeSK Innovation Co., Ltd.
InventorsGwi Gwon Kang, Dong Hoon Lee, Jae Kyu Jin
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Abstract
A microporous polyimide-based film having excellent strength, permeability, and thermal stability is used as a separator for a lithium ion secondary battery, and a method of producing the same is provided.
Claims11
A method for producing a microporous polyimide-based film, comprising:
- applying a polymer solution including poly(amic acid), a solvent for dissolving the poly(amic acid), a phase separation agent for phase-separation from the poly(amic acid), inorganic particles with a hydrophobized surface, an imidizing catalyst, and a dehydrating agent to a base material;
- producing a phase-separated structure by drying the base material;
- removing the phase separation agent from the phase-separated structure and producing a microporous film;
- and
- imidizing unreacted poly(amic acid) by drying the microporous film.
2 more elements
A microporous polyimide-based film, including 4 wt % to 30 wt % of inorganic particles with a hydrophobized surface,
- wherein a film thickness is 10 μm to 50 μm, puncture strength is 0.05 N/μm to 0.30 N/μm, permeability standardized at a thickness of 20 μm is 50 to 500 sec/100 cc, porosity is 40% to 65%, an average pore size measured using a half-dry method is 20 nm to 100 nm, a maximum pore size measured using a bubble point method is equal to or less than 300 nm, a shrinkage ratio at 200° C. is equal to or less than 5%.
Dependencies are inferred from the claim text.