Method of preparing encapsulated pigment dispersions with minimal free polymer
US8957134B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 15, 2011 |
| Grant date | Feb 17, 2015 |
| Priority date | — |
| Expiry date | Dec 15, 2031 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08L33/10
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
A process for encapsulating pigment dispersions is provided where a pigment is dispersed with a polymeric dispersant in an aqueous solvent system. The free polymer dispersant in the pigment dispersion is limited to less than 0.12 grams per gram of pigment. This dispersed pigment is then encapsulated by adding acrylate monomers and optionally acrylic and vinyl monomers and polymerizing. In the encapsulated pigment dispersion the weight ratio of final free polymer to polymer found to the final encapsulated pigment is less than 0.9. The free polymer dispersant is measured by a centrifugation method and the final free polymer is measured by a density gradient centrifugation method. Such encapsulated pigment dispersions may be used in inkjet inks and are stable to heat, aging test conditions, and solvent challenges. Prints from these inks have better durability.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.