Hollow microspheres
US4859711A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 19, 1988 |
| Grant date | Aug 22, 1989 |
| Priority date | — |
| Expiry date | Jul 19, 2008 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08J9/08
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A process of forming hollow microspheres containing carbon or a polymer which is a carbon precursor. The process comprises forming a solution in a liquid solvent of a polymer having the following properties (a) a molecular weight of at least 10,000 and a long chain structure; (b) an ability to be coagulated by or precipitated from the solution by a non-solvent for the polymer; (c) an ability to form a continuous stretchable film when coagulated or precipitated from solution; (d) a chemical structure which is infusible or capable of being rendered infusible, and (e) a high carbon yield of at least 30% by weight upon being carbonized in a non-reactive atmosphere. An insoluble particulate blowing agent is incorporated into the solution and the solution is then divided into droplets and the droplets are introduced into a liquid bath containing a suitable non-solvent for the polymer. The non-solvent causes the polymer to precipitate or coagulate rapidly and simultaneously the blowing agent is decomposed to generate a gas within the droplets so that hollow microspheres are formed. The microspheres are then optionally subjected to carbonization in a non-reactive atmosphere at high tempera…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.