When using liquid colors for coloring plastics, peristaltic pumps and dosing systems are used whose pump heads must either be replaced or cleaned when the color is changed. Rowasol has now developed the Dispersion-Rowapurge for the latter. It enables effective and gentle rinsing and speeds up the color change on both the injection molding machine and the extruder.
No color carryover
Rowasol has modified the Rowaclean cleaning agent to remove the liquid color from previous production from the pump heads of micro annular gear, progressive cavity or gear pumps. This is a liquid cleaning concentrate based on modified fatty acid esters. By adding a color-neutral, gently abrasive special mineral, the cleaning effect could be increased. The resulting product, called HM 1108.01 Rowapurge, rinses paint out of the pump head even faster and more thoroughly. As a result, both paint carryover and set-up times can be minimized.
Test on processing machine
A test shows the effect of Rowapurge in processing machines: first, a polypropylene was mixed with around one percent Red 254 pigment, an organic pigment that is difficult to rinse out, and displaced from the injection molding machine with the natural plastic. The process was then repeated with one percent Rowapurge. This led to a significant reduction in the number of rinsing cycles.
Exposure increases cleaning performance
Even better results are achieved if the dyed plastic is first continuously ejected into the open air, the screw is then fed with plastic and Rowapurge and the mixture is allowed to act for two to three minutes so that the fatty acid esters it contains can dissolve color residues and other contaminants. There is no chemical reaction and no foaming, so Rowapurge itself can be removed quickly.