Crosslinked polyolefin separator and method of preparing the same

Patent metadata

Field	Value
Publication number	US-9887405-B2
Application number	US-201514928721-A
Country	US
Kind code	B2
Filing date	Oct 30, 2015
Priority date	Oct 31, 2014
Publication date	Feb 6, 2018
Grant date	Feb 6, 2018

Abstract

Disclosed is a method of preparing a crosslinked polyolefin separator including preparing a silane grafted polyolefin solution using a polyolefin having a weight average molecular weight higher than or equal to 200,000, a diluent, an alkoxy group containing vinylsilane, and an initiator, forming the silane grafted polyolefin solution in a sheet shape and stretching, extracting the diluent from the stretched sheet to produce a porous membrane, and crosslinking the porous membrane in the presence of water, and a crosslinked polyolefin separator.

First claim

What is claimed is:

1. A method of preparing a crosslinked polyolefin separator, comprising:
preparing a silane grafted polyolefin solution using a polyolefin having a weight average molecular weight higher than or equal to 200,000, a diluent, an alkoxy group containing vinylsilane, and an initiator;
forming the silane grafted polyolefin solution in a sheet shape and stretching;
extracting the diluent from the stretched sheet to produce a porous membrane; and
crosslinking the porous membrane in the presence of water.

2. The method of preparing a crosslinked polyolefin separator according to claim 1 , wherein the preparing of a silane grafted polyolefin solution comprises feeding a polyolefin, a diluent, an alkoxy group containing vinylsilane, and an initiator into an extruder, mixing them, and performing reactive extrusion.

3. The method of preparing a crosslinked polyolefin separator according to claim 1 , wherein a weight ratio between the polyolefin and the diluent in the silane grafted polyolefin solution ranges from 50:50 to 20:80.

4. The method of preparing a crosslinked polyolefin separator according to claim 1 , wherein a content of the alkoxy group containing vinylsilane in the silane grafted polyolefin solution is 0.1 parts by weight to 10 parts by weight per the total 100 parts by weight of the polyolefin and the diluent, and a content of the initiator in the silane grafted polyolefin solution is 0.2 parts by weight to 100 parts by weight per 100 parts by weight of the alkoxy group containing vinylsilane.

5. The method of preparing a crosslinked polyolefin separator according to claim 1 , wherein the polyolefin includes polyethylene; polypropylene; polybutylene; polypentene:polyhexene:polyoctene:copolymers of at least two of ethylene, propylene, butene, pentene, 4-methylpentene, hexene and octene; or mixtures thereof.

6. The method of preparing a crosslinked polyolefin separator according to claim 1 , wherein the diluent includes at least one selected from the group consisting of paraffin oils, mineral oils, waxes, soybean oils, phthalic acid esters, aromatic ethers, fatty acids having 10 to 20 carbon atoms, fatty acid alcohols having 10 to 20 carbon atoms, and fatty acid esters.

7. The method of preparing a crosslinked polyolefin separator according to claim 1 , wherein the alkoxy group containing vinylsilane is at least one selected from the group consisting of trimethoxyvinylsilane, triethoxyvinylsilane, and triacetoxyvinylsilane.

8. The method of preparing a crosslinked polyolefin separator according to claim 1 , wherein the forming in a sheet shape and stretching comprises extruding the silane grafted polyolefin solution through a die to form an extruded product; cooling the extruded product and forming in a sheet shape; and stretching the product formed in a sheet shape sheet biaxially in a longitudinal direction and a transverse direction to form a stretched sheet.

9. The method of preparing a crosslinked polyolefin separator according to claim 1 ,
before the crosslinking, further comprising:
heat-setting the porous membrane.

10. The method of preparing a crosslinked polyolefin separator according to claim 1 , wherein the crosslinking is performed on the porous membrane under the conditions of 50° C. to 100° C. of temperature and 50% to 100% of humidity.

Assignees

• Lg Chemical Ltd

Inventors

• Park Cheon Il
• Bae Won Sik
• Ryu Bi Oh
• Kim Kyoung Min
• Song Heon Sik

Classifications

• B29C35/041 Primary

  using liquids · CPC title

• H01M50/494

  Tensile strength · CPC title

• H01M50/489

  Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties · CPC title

• H01M50/417

  Polyolefins · CPC title

• H01M50/406

  Moulding; Embossing; Cutting · CPC title