# US 10,246,568 B2 · Production of porous materials by the expansion of polymer gels

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- Number: US 10,246,568 B2
- Document ID: US10246568B2
- Status: Granted
- Kind: B2
- Application number: 15/036,769
- Filed: 2014-11-17
- Published: 2016-09-29
- Granted: 2019-04-02
- Earliest claimed: 2013-11-15
- Assignees: SUMTEQ GmbH
- Applicants: Sumteq GmbH
- Inventors: Reinhard Strey; Roland Oberhoffer; Alexander Müller
- Web page: https://patentgrep.com/patent/US10246568B2

## CPC

- C08J 9/122: {Hydrogen, oxygen, CO2, nitrogen or noble gases}
- C08J 9/0014: {Use of organic additives}
- C08J 9/0023: {containing oxygen}
- C08J 9/141: {Hydrocarbons}
- C08J 9/18: by impregnating polymer particles with the blowing agent
- C08J 9/28: by elimination of a liquid phase from a macromolecular composition or article, e.g. drying of coagulum
- C08J 9/34: Chemical features in the manufacture of articles consisting of a foamed macromolecular core and a macromolecular surface layer having a higher density than the core
- C08K 5/07: Aldehydes; Ketones
- B29C 44/3453: {Feeding the blowing agent to solid plastic material}
- C08J 2201/026: Crosslinking before of after foaming
- C08J 2201/03: Extrusion of the foamable blend
- C08J 2201/032: Impregnation of a formed object with a gas
- C08J 2201/0502: the liquid phase being organic
- C08J 2203/06: CO2, N2 or noble gases
- C08J 2203/08: Supercritical fluid
- C08J 2203/14: Saturated hydrocarbons, e.g. butane; Unspecified hydrocarbons
- C08J 2205/024: Organogel, i.e. a gel containing an organic composition
- C08J 2205/042: Nanopores, i.e. the average diameter being smaller than 0,1 micrometer
- C08J 2205/044: Micropores, i.e. average diameter being between 0,1 micrometer and 0,1 millimeter
- C08J 2300/22: Thermoplastic resins
- C08J 2323/06: Polyethene
- C08J 2323/12: Polypropene
- C08J 2325/06: Polystyrene
- C08J 2327/06: Homopolymers or copolymers of vinyl chloride
- C08J 2333/12: Homopolymers or copolymers of methyl methacrylate
- C08J 2367/04: Polyesters derived from hydroxy carboxylic acids, e.g. lactones (C08J2367/06 takes precedence)
- C08J 2369/00: Characterised by the use of polycarbonates; Derivatives of polycarbonates
- C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29)
- C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09)
- 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)

## Abstract

A method for producing porous materials is disclosed. The porous materials can be produced by expansion of polymer gels.

## Claims

### Claim 1

A method of producing a micro- or nano-porous polymer material,
swelling a polymer starting material using a plasticizer at a predetermined temperature to make the polymer starting material visco-elastic deformable, wherein the polymer starting material is at least partially crosslinked and the crosslinker content in the polymer starting material is in a range from 0.01 to 10 mol %, wherein the predetermined temperature is in a range from 0 to 100° C.;
subsequently, contacting the swollen polymer starting material with a foaming agent under a first pressure; and
subsequently, depressurizing from the first pressure to a second pressure such that the swollen polymer starting material further expands and solidifies to obtain a micro- or nanoporous material.

### Claim 2 (depends on 1)

The method according to claim 1,
wherein the polymer starting material consists of one or several particularly thermoplastic polymers,
wherein the plasticizer is selected from acetone and other polar aprotic solvents and a group of alkanes consisting of butane, pentane, hexane and cyclohexane,
wherein the mass ratio of polymer starting material to plasticizer is 10:0.5 to 1:3, and
wherein swelling of the polymer starting material is performed for a time period of 0.1 second to 100 hour.

### Claim 3 (depends on 1)

The method according to claim 1, wherein the swelling of polymer starting material results in a dense packing of polymer latices having a mean particle size in the micrometer and nanometer ranges.

### Claim 4 (depends on 1)

The method according to claim 1, wherein the swelling of polymer starting material is carried out in an extruder.

### Claim 5 (depends on 1)

The method according to claim 1, wherein the foaming agent comprises at least one selected from CO2 and other foaming agents that are completely miscible with the plasticizer under high pressure, and
wherein the first pressure is in a range from 10 to 300 bar.

### Claim 6 (depends on 1)

The method according to claim 1, wherein depressurizing from the first pressure to the second pressure takes place within 0.1 to 60 second.

### Claim 7 (depends on 1)

The method according to claim 1, wherein the obtained micro- or nanoporous polymer material has a density from 0.5% to 50% of the density of the polymer starting material and a mean pore size from 0.01 to 10 μm.

### Claim 8 (depends on 1)

The method according to claim 1, wherein the polymer starting material consists of one or more selected from a group of polymethyl methacrylate (PMMA), polystyrene (PS), polyvinyl chloride (PVC), polylactide (PL), polyethylene (PE), polypropylene (PP), polycarbonate (PC) and cellophane.

### Claim 9 (depends on 1)

The method according to claim 1, wherein the mass ratio of polymer starting material to plasticizer is 10:2 to 1:1.

### Claim 10 (depends on 1)

The method according to claim 1, wherein swelling of the polymer starting material is performed for a time period of 1 second to 1 hour.

### Claim 11 (depends on 1)

The method according to claim 1, wherein that the obtained micro- or nanoporous polymer material is not soluble in its own monomer.

### Claim 12 (depends on 5)

The method according to claim 5,
wherein the foaming agent comprises at least one alkane selected from a group consisting of methane, ethane, and propane, and
wherein the first pressure is in a range from 50 to 200 bar.

### Claim 13 (depends on 1)

The method according to claim 1, wherein the first pressure is 250 bar and the second pressure is 1 bar, wherein the depressurizing from the first pressure to the second pressure takes place in 1 second.