Binder composition for use in three dimensional printing
US5660621A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 29, 1995 |
| Grant date | Aug 26, 1997 |
| Priority date | — |
| Expiry date | Dec 29, 2015 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S264/72
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A binder composition for three dimensional printing of parts is disclosed which is stable during storage and passage through a printhead, yet able to gel under the conditions existing in a powder bed. The binder composition comprises colloidal silica, a catalyst able to promote gelation of the composition when the composition is below a predetermined pH value, and a base able to maintain the pH of the composition above the predetermined value at which the composition gels. Preferably, the catalyst is polyethylene glycol or another ethylene oxide-derived polymer, and the base is triethanolamine. Upon impact with a powder bed, the pH of the binder composition is reduced, as by adding an acid such as citric acid to the powder, thereby causing the binder to gel in the powder.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.