US 11,236,468 B2 · Porous sheet

Abstract

The present invention relates to a porous sheet comprising cellulose fibers having an average fiber diameter ranging from 20 to 500 nm; cut fibers having an average fiber diameter ranging from 1.5 to 20 μm; and a hydrophilic polymer binder, wherein an amount of the cut fibers is 1% by weight or more and 80% by weight or less based on the total weight of the cellulose fibers and the cut fibers, and an amount of the hydrophilic polymer binder is 5 parts by weight or more and 30 parts by weight or less with respect to 100 parts by weight of the total weight of the cellulose fibers and the cut fibers. The porous sheet of the present invention can exhibit a superior strength (in particular, both tear strength and tensile strength), and exhibits a superior performance as a separator for an electrochemical device.

Claims20

Dependent claims

A porous sheet comprising:

cellulose fibers having an average fiber diameter ranging from 20 to 500 nm;
cut fibers having an average fiber diameter ranging from 1.5 to 20 μm;
and
a hydrophilic polymer binder,
wherein
an amount of said cellulose fibers is 50% by weight or more and 95% by weight or less based on the total weight of all fibers in the porous sheet,
an amount of said hydrophilic polymer binder is 5 parts by weight or more and 30 parts by weight or less with respect to 100 parts by weight of the total weight of said cellulose fibers and said cut fibers,
said cellulose fibers comprise fibers having a diameter of 1 μm or more in an amount ranging from 5 to 40% by weight based on the total weight of the cellulose fibers, and
said cut fibers have an average fiber length of from 1 mm to 10 mm.

6 more elements

Dependencies are inferred from the claim text.

Porous sheet

Life of this patent

Porous sheet

Life of this patent

Abstract

Claims20