Tracking ink particle size using a Mastersizer 2000

Using Malvern’s Mastersizer 2000 particle size analyzer, a leading ink-jet ink manufacturer has succeeded for the first time in monitoring particle size reduction throughout the entire milling process.

Thanks to the Mastersizer 2000’s extremely broad measurement range of 0.02 to 2000 microns it can measure the size of both agglomerates and primary ink particles equally well. This capability also enabled suspension stability to be investigated.

Pigment based ink jet inks are being used increasingly for applications where durability and moisture resistance are issues. They are produced by milling pigment dispersions. The final particles must be 200 nm or less in order to avoid blockages at the print head, defect formation within the printed film and inconsistent colour densities.

Data from the Mastersizer 2000 clearly showed the break-up of aggregates that were present initially, and the exponential reduction of particle size in the mill. Confirmation that the final material met the required specification was also provided. Longer term particle size monitoring showed that over a period of three days, potentially problematic agglomerates were formed.

The Mastersizer 2000 is a fully automated, SOP-driven instrument designed for the rapid analysis of either wet or dry samples. Its broad measurement range can be accessed without making changes to the optical system enhancing its ease of use/flexibility.