Polymer nanocomposite foams
US6759446B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 2, 2002 |
| Grant date | Jul 6, 2004 |
| Priority date | — |
| Expiry date | Aug 12, 2022 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08J2333/12
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
Nano-sized particles such as nano-clays can be mixed with polymers through either melt compounding or in-situ polymerization. By modifying the particle surface with various surfactants and controlling processing conditions, we are able to achieve either intercalated (partial dispersion) or exfoliated (full dispersion) nano-clay distribution in polymers with the clay content up to 35% by weight. When a blowing agent is injected into the nanocomposite in an extruder (a continuous mixer) or a batch mixer, polymeric foam can be produced. Supercritical carbon dioxide, an environmentally friendly, low-cost, non-flammable, chemically benign gas is used as the blowing agent. This process forms a microcellular foam with very high cell density (>109 cells/cc) and small cell size (<5 microns) can be achieved by controlling the CO2 content, melt and die temperature, and pressure drop rate.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.