Cross-Linked Polyolefin Separator and Manufacturing Method Therefor

Patent metadata

Field	Value
Publication number	US-2021125792-A1
Application number	US-201917044026-A
Country	US
Kind code	A1
Filing date	Nov 29, 2019
Priority date	Dec 21, 2018
Publication date	Apr 29, 2021
Grant date	—

Abstract

A crosslinked polyolefin separator and a method of making the same are disclosed herein. In some embodiments, a crosslinked polyolefin separator includes inorganic particles and a crosslinked polyolefin having Si—O—Si crosslinking bonds, wherein the inorganic particles are chemically bound to silicon (Si) atoms of the Si—O—Si crosslinking bonds by oxygen (O) atoms. The crosslinked polyolefin separator has low resistance, high air permeability and improved heat resistance.

First claim

1 . A silane-crosslinked polyolefin separator comprising:
inorganic particles; and a crosslinked polyolefin having Si—O—Si crosslinking bonds, wherein silicon (Si) atoms of the Si—O—Si crosslinking bonds are chemically bound to the inorganic particles by oxygen (O) atoms.

2 . The silane-crosslinked polyolefin separator according to claim 1 , wherein at least one oxygen (O) is chemically bound to the inorganic particles.

3 . The silane-crosslinked polyolefin separator according to claim 1 , wherein the inorganic particles are metal particles, and wherein a number of the oxygen (O) atoms used to chemically bond a silicon atom to a metal atom of the inorganic particles is the same as the oxidation number of the metal atom.

4 . The silane-crosslinked polyolefin separator according to claim 1 , wherein the crosslinked polyolefin comprises a compound represented by the following Chemical Formula 1:

wherein M is metal, each of l, m and n is an integer of 0 or more, and each of R 1 , R 2 and R 3 independently represents a C1-C10 alkoxy group or C1-C10 alkyl group, with the proviso that at least one of R 1 , R 2 and R 3 is an alkoxy group.

5 . The silane-crosslinked polyolefin separator according to claim 1 , wherein the content of the inorganic particles is 5-70 wt % based on the total weight of the crosslinked polyolefin separator.

6 . The silane-crosslinked polyolefin separator according to claim 1 , wherein the inorganic particles are prepared from a metal hydroxide.

7 . The silane-crosslinked polyolefin separator according to claim 6 , wherein a metal of the metal hydroxide comprises any one of aluminum, magnesium, silicon, zirconium, calcium, strontium, barium, antimony, tin, zinc and rare earth metal elements, or at least two elements of them.

8 . The silane-crosslinked polyolefin separator according to claim 6 ,
wherein the metal hydroxide comprises any one of aluminum hydroxide, magnesium hydroxide, calcium hydroxide and boehmite, or at least two of them.

9 . A method for manufacturing a crosslinked polyolefin separator, comprising the steps of:
mixing a polyolefin, a diluting agent, an initiator, a crosslinking catalyst and surface-treated inorganic particles in an extruder, and then reactively extruding the mixture to form a silane-grafted polyolefin composition, wherein the surface-treated inorganic particles are prepared by surface-treating with an alkoxysilane containing a carbon-carbon double bond; molding and orienting the extruded silane-grafted polyolefin composition in the form of a sheet; extracting the diluting agent from the oriented sheet to obtain a porous membrane; thermally fixing the porous membrane; and crosslinking the thermally fixed porous membrane in the presence of moisture.

10 . The method for manufacturing a crosslinked polyolefin separator according to claim 9 , wherein the polyolefin has a weight average molecular weight of 200,000-1,000,000.

11 . The method for manufacturing a crosslinked polyolefin separator according to claim 9 , wherein the surface-treated inorganic particles having the alkoxysilane containing a carbon-carbon double bonded group coupled thereto via oxygen (O) atoms.

12 . The method for manufacturing a crosslinked polyolefin separator according to claim 9 , wherein the surface-treated inorganic particles comprising compounds derived from hydrolysis of the alkoxysilane containing the carbon-carbon double bonded group, wherein the compounds are chemically bound to the inorganic particles via oxygen atoms.

13 . The method for manufacturing a crosslinked polyolefin separator according to claim 9 , wherein the surface-treated inorganic particles are obtained by a method comprising:
hydrolyzing the alkoxysilane containing the carbon-carbon double bonded group to prepare a silanol containing a carbon-carbon double bonded group; and mixing the silanol with inorganic particles containing at least one hydroxyl group to prepare the surface-treated inorganic particles.

14 . The method for manufacturing a crosslinked polyolefin separator according to claim 9 , wherein mixing the silanol with the inorganic particles is carried out at 25-80° C.

15 . The method for manufacturing a crosslinked polyolefin separator according to claim 9 , wherein the silane-grafted polyolefin composition comprises polyolefin, silane grafted to the polyolefin, and inorganic particles bound to the silicon atoms of the grafted silane via oxygen (O) atoms.

16 . The method for manufacturing a crosslinked polyolefin separator according to claim 9 , wherein crosslinking the thermally fixed porous membrane in the presence of moisture comprises:
moisture-crosslinking the alkoxysilane with the polyolefin.

17 . The method for manufacturing a crosslinked polyolefin separator according to claim 16 , wherein the alkoxysilane comprises a compound represented by the following Chemical Formula 2:

wherein each of R 1 , R 2 and R 3 independently represents a C1-C10 alkoxy group or C1-C10 alkyl group, with the proviso that at least one of R 1 , R 2 and R 3 represents an alkoxy group; and
R represents a vinyl group, acryloxy group, methacryloxy group, or a C1-C20 alkyl group, wherein at least one hydrogen atom of the alkyl group is substituted with a vinyl group, acryloxy group, or methacryloxy group.

18 . The method for manufacturing a crosslinked polyolefin separator according to claim 17 , wherein the alkoxysilane selected from the group consisting of vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, (3-methacryloxypropyl)trimethoxysilane, (3-methacryloxypropyl) triethoxysilane, vinylmethyl dimethoxysilane, vinyl-tris(2-methoxyethoxy)silane, vinylmethyldiethoxysilane or a mixture thereof.

Assignees

• Lg Chemical Ltd

Inventors

• Ryu Bi-Oh
• Lee Joo-Sung
• Bae Won-Sik

Classifications

• H01M50/443

  Particulate material · CPC title

• Y02E60/10

  Energy storage using batteries · CPC title

• B29K2105/24

  crosslinked or vulcanised · CPC title

• B01D69/148

  Organic/inorganic mixed matrix membranes · CPC title

• B29C48/91

  Heating, e.g. for cross linking · CPC title