When using liquid colors for coloring plastics, beside peristaltic pumps also other dosing systems are used whose pump heads must either be replaced or cleaned when the color is changed. For the latter, ROWASOL has now developed a dispersion that enables effective and gentle rinsing and also speeds up the color change on the injection molding machine and extruder.
The peristaltic pump is still the dosing system of choice in many applications for the simple liquid coloring of plastic products. The advantages of a quick hose change are obvious, especially with a large variety of colors and many color changes in a short time, as no peripherals need to be cleaned or purged. Even with the relatively new and very precise piston pumps, the color change is quick, as here a set consisting of piston and connecting hoses is also changed for each color. The investment costs for a so-called piston set are many times higher than for a hose, possibly with quick couplings.
However, today there is a wide range of other modern dosing systems to choose from if, for example, high precision is required, high pressure is needed to inject the liquid color or handling the hose is undesirable. Depending on the application, innovative micro annular gear pumps, progressive cavity pumps or gear pumps can be used. To remove the liquid color of the previous production from these pump heads, the proven ROWACLEAN, a liquid cleaning concentrate based on modified fatty acid esters, was previously recommended, which in turn can be very easily displaced by the new liquid color for the upcoming order.
In order to optimize the cleaning effect, ROWACLEAN has been further developed and a color-neutral, gently abrasive special mineral has been added. The resulting product, called HM 1108.01 ROWAPURGE, removes the color even faster and more thoroughly from the pump head, minimizing both color carryover and set-up times. But ROWAPURGE is also convincing on the processing machine, as the adjacent illustration shows. For comparison purposes, a polypropylene was mixed with approx. 1 % Red 254 pigment, an organic pigment that is difficult to purge, and displaced from the injection molding machine with the natural plastic. The process was then repeated with approx. 1 % ROWAPURGE, which led to a significant reduction in the number of rinsing cycles.
Of course, even better results are achieved if the colored plastic is first continuously ejected into the open air, the screw is then fed with plastic and ROWAPURGE and the mixture is allowed to work for 2-3 minutes so that the fatty acid esters can dissolve color residues and other contaminants. There is no chemical reaction and no foaming, so that ROWAPURGE itself can be removed quickly. Another advantage over chemical cleaning compounds is the comparatively low costs and therefore also the sales prices. All recipe components are FDA-compliant, meaning that the product can be used without hesitation in the manufacture of food packaging or toys, for example. The new ROWAPURGE is now available from stock.
The peristaltic pump is still the dosing system of choice in many applications for the simple liquid coloring of plastic products. The advantages of a quick hose change are obvious, especially with a large variety of colors and many color changes in a short time, as no peripherals need to be cleaned or purged. Even with the relatively new and very precise piston pumps, the color change is quick, as here a set consisting of piston and connecting hoses is also changed for each color. The investment costs for a so-called piston set are many times higher than for a hose, possibly with quick couplings.
However, today there is a wide range of other modern dosing systems to choose from if, for example, high precision is required, high pressure is needed to inject the liquid color or handling the hose is undesirable. Depending on the application, innovative micro annular gear pumps, progressive cavity pumps or gear pumps can be used. To remove the liquid color of the previous production from these pump heads, the proven ROWACLEAN, a liquid cleaning concentrate based on modified fatty acid esters, was previously recommended, which in turn can be very easily displaced by the new liquid color for the upcoming order.
In order to optimize the cleaning effect, ROWACLEAN has been further developed and a color-neutral, gently abrasive special mineral has been added. The resulting product, called HM 1108.01 ROWAPURGE, removes the color even faster and more thoroughly from the pump head, minimizing both color carryover and set-up times. But ROWAPURGE is also convincing on the processing machine, as the adjacent illustration shows. For comparison purposes, a polypropylene was mixed with approx. 1 % Red 254 pigment, an organic pigment that is difficult to purge, and displaced from the injection molding machine with the natural plastic. The process was then repeated with approx. 1 % ROWAPURGE, which led to a significant reduction in the number of rinsing cycles.
Of course, even better results are achieved if the colored plastic is first continuously ejected into the open air, the screw is then fed with plastic and ROWAPURGE and the mixture is allowed to work for 2-3 minutes so that the fatty acid esters can dissolve color residues and other contaminants. There is no chemical reaction and no foaming, so that ROWAPURGE itself can be removed quickly. Another advantage over chemical cleaning compounds is the comparatively low costs and therefore also the sales prices. All recipe components are FDA-compliant, meaning that the product can be used without hesitation in the manufacture of food packaging or toys, for example. The new ROWAPURGE is now available from stock.
