# US 12,759,214 B2 · Biaxially oriented porous membranes, composites, and methods of manufacture and use

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- Number: US 12,759,214 B2
- Document ID: US12759214B2
- Status: Granted
- Kind: B2
- Application number: 15/582,866
- Filed: 2017-05-01
- Published: 2017-09-21
- Granted: 2026-10-13
- Earliest claimed: 2010-03-12
- Assignees: Celgard, LLC
- Applicants: Celgard, LLC
- Inventors: Xiaomin Zhang; Gerald P. Rumierz; Karl F. Humiston; Charles E. Haire; Tyrone S. Fields; Michael A. Braswell; Ronald A. Proctor
- Web page: https://patentgrep.com/patent/US12759214B2

## CPC

- B29C 55/143: {firstly parallel to the direction of feed and then transversely thereto}
- B01D 67/0027: {by stretching}
- B29C 55/16: simultaneously
- C08G 69/00: Macromolecular compounds obtained by reactions forming a carboxylic amide link in the main chain of the macromolecule (products obtained from isocyanates or isothiocyanates C08G18/00; polyamide-imides C08G73/14)
- H01M 10/0565: Polymeric materials, e.g. gel-type or solid-type
- H01M 50/406: Moulding; Embossing; Cutting
- H01M 50/417: Polyolefins
- H01M 50/454: comprising a non-fibrous layer and a fibrous layer superimposed on one another
- H01M 50/491: Porosity
- H01M 50/494: Tensile strength
- H01M 50/581: in response to temperature
- B01D 2325/021: Pore shapes
- B01D 2325/0283: Pore size
- B29L 2031/755: {Membranes, diaphragms}
- H01M 10/0525: Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
- Y10T 428/249978: Voids specified as micro
- Y10T 442/3854: Woven fabric with a preformed polymeric film or sheet
- Y10T 442/40: Knit fabric [i.e., knit strand or strip material]
- Y10T 442/674: Nonwoven fabric with a preformed polymeric film or sheet
- B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00)
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- B29L: INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

At least a selected microporous membrane is made by a dry-stretch process and has substantially round shaped pores and a ratio of machine direction tensile strength to transverse direction tensile strength in the range of 0.5 to 6.0. The method of making the foregoing microporous membrane may include the steps of: extruding a polymer into a nonporous precursor, and biaxially stretching the nonporous precursor, the biaxial stretching including a machine direction stretching and a transverse direction stretching, the transverse direction including a simultaneous controlled machine direction relax. At least selected embodiments of the invention may be directed to biaxially oriented porous membranes, composites including biaxially oriented porous membranes, biaxially oriented microporous membranes, biaxially oriented macroporous membranes, battery separators, filtration media, humidity control media, flat sheet membranes, liquid retention media, and the like, related methods, methods of manufacture, methods of use, and the like.

## Claims

### Claim 1

A method of permitting selective passage of moisture vapor and blockage of liquid water in an HVAC system comprising the steps of:
providing a porous beta-nucleated HEPA/ULPA membrane comprising at least two polypropylene layers and two polyethylene layers bonded together, and further comprising at least one nonwoven layer; the membrane having pores with a three dimensional sphericity factor from 1.0 to 2.0, a porosity of about greater than 60% to 90%, a ratio of machine direction tensile strength to transverse direction tensile strength in the range of about 0.5 to 5.0, a JIS Gurley air permeability less than about 5 seconds/100 cc, a mean flow pore diameter of at least about 0.04 microns, an Aquapore size of at least about 0.07 microns, and a hydro-head pressure greater than about 140 psi, and
facilitating passage of the moisture vapor through the membrane in the HVAC system.

### Claim 2 (depends on 1)

The method of claim 1 wherein the beta-nucleated polypropylene film is made by a dry-stretch process including the steps of:
extruding the two polypropylene layers into a multi-layer nonporous precursor, and
biaxially stretching the nonporous precursor, the biaxial stretching including a machine direction stretching and a transverse direction stretching, the transverse direction stretching including a simultaneous controlled machine direction relax.

### Claim 3 (depends on 2)

The method according to claim 2 wherein the biaxially stretching includes the machine direction stretching followed by the transverse direction stretching with simultaneous machine direction relax.

### Claim 4 (depends on 3)

The method according to claim 3 wherein the machine direction stretching including one or more machine direction stretching steps.

### Claim 5 (depends on 3)

The method according to claim 3 wherein the transverse direction stretching including one or more transverse direction stretching steps.

### Claim 6 (depends on 1)

The method of claim 1 wherein the porous membrane having a thickness of at least about 8 microns, a transverse direction tensile strength of at least about 300 kgf/cm2, a standard deviation of mean flow pore diameter of less than about 0.025, a water intrusion pressure of at least about 80 psi, and a WVTR of at least about 8,000 g/m2-day.

### Claim 7 (depends on 1)

The method of claim 1 wherein the porous membrane having a transverse direction shrinkage of less than about 1.0% at 90° C.

### Claim 8 (depends on 1)

The method of claim 1 wherein the porous membrane having a transverse direction shrinkage of less than about 1.5% at 105° C.

### Claim 9 (depends on 1)

The method of claim 1 wherein the porous membrane having a transverse direction shrinkage of less than about 3.0% at 120° C.

### Claim 10 (depends on 1)

The method of claim 1 wherein the porous membrane having a thickness in a range of about 8 microns to 80 microns.

### Claim 11 (depends on 1)

The method of claim 1 wherein the porous membrane comprises one of a blown film or a slot die film.

### Claim 12 (depends on 1)

The method of claim 1 with said porous membrane further having a porosity of about 75 to 90%, a ratio of machine direction tensile strength to transverse direction tensile strength in the range of about 1.0 to 5.0, a mean flow pore diameter of at least about 0.05 microns, an Aquapore size of at least about 0.08 microns, and a hydro-head pressure greater than about 145 psi.

### Claim 13 (depends on 1)

The method of claim 1 with said porous membrane further having a ratio of machine direction tensile strength to transverse direction tensile strength in the range of about 0.5 to 5.0, a mean flow pore diameter in a range of about 0.04 to 0.250 microns, a bubble point diameter in the range of about 0.049 to 0.1078 microns, a hydro-head pressure greater than about 140 psi, a water intrusion pressure of at least about 80 psi, and a water vapor transmission rate (WVTR) of ≥8000 g/m2-day.

### Claim 14 (depends on 1)

The method of claim 1, wherein the pores have an aspect ratio of length (machine direction) to width (transverse direction) in the range of from 0.75 to 1.25.

### Claim 15

A method of permitting selective passage of moisture vapor and blockage of liquid water in an HVAC system comprising the steps of:
providing a membrane comprising at least one layer of porous polymer film made by a dry-stretch process, and a nonwoven, wherein said membrane has substantially round shaped pores, a porosity of about 40% to 90%, a ratio of machine direction tensile strength to transverse direction tensile strength in the range of about 0.5 to 5.0, a Gurley of less than about 100, a mean flow pore diameter of at least about 0.04 microns, an Aquapore size of at least about 0.07 microns, and a hydro-head pressure greater than about 140 psi; and
facilitating passage of the moisture vapor through the membrane in the HVAC system.