Multi-layer microporous film for batteries having shut-off function
AssigneeTreofan Germany GmbH & Co. KG
InventorsBertram Schmitz, Detlef Busch
Life of this patent
Estimating the term…
Abstract
The invention relates to a biaxially oriented, multilayer microporous foil including one layer made from propylene homopolymer, a propylene block copolymer, a polyethylene and β-nucleating agent, and at least one further porous layer.
Claims21
A biaxially oriented, multilayer, microporous foil with shut-off function whose microporosity is created by converting β-crystalline polypropylene when the foil is stretched, and which comprises at least one shut-off layer I and at least one porous layer II, wherein the shut-off layer contains propylene homopolymer and propylene block copolymer and β-nucleating agent and polyethylene, and the porous layer II contains propylene homopolymer and propylene block copolymer and β-nucleating agent, wherein the foil has a Gurley value of 50 to 5000 s, an e-modulus in the lengthwise direction >300 N/mm2 to 1,800 N/mm2, and >500 N/mm2 to 3,000 N/mm2 in the transverse direction, and after exposure to a temperature of 130° C. for 5 minutes the foil exhibits a Gurley value of at least 5000 s, wherein the Gurley value after this temperature treatment is at least 1000 s higher than before.
A biaxially oriented, multilayer, microporous foil with shut-off function whose microporosity is created by converting β-crystalline polypropylene when the foil is stretched, and which comprises:
- at least one shut-off layer I comprising:
- propylene homopolymer;
- propylene block copolymer;
- β-nucleating agent;
- and
- polyethylene;
- and
- at least one porous layer II comprising:
- propylene homopolymer;
- propylene block copolymer;
- and
- β-nucleating agent;
- and
- wherein the foil has a Gurley value of 50 to 5000 s, an e-modulus in the lengthwise direction of greater than 300 N/mm2 to 1,800 N/mm2, and an e-modulus in the transverse direction of greater than 500 N/mm2 to 3,000 N/mm2;
- and
- wherein the shut-off function comprises an increase in the Gurley value of the foil of at least 1000 s after heat treatment at 130° C. for 5 minutes.
Dependencies are inferred from the claim text.