There are several factors that can impact color, including the type of resin used, additives, texture and shape. Visual perception is another factor to consider.
When plastics companies tackle these factors on the shop floor, it is important to consider colors and custom compounds, which can be a key component of the process.
Compounders are working in markets where capacity has been outpacing demand. There also has been a lot of consolidation, particularly on the masterbatch side.
The trend also has been for processors to buy natural resins and color it at the press. This trend is largely driven by cost. As volume increases, so does the likelihood that the resin will be colored press-side.
Colored polymer components provide functionality and aesthetics in medical applications. Colors are used to differentiate product type, size, or model. Certain colors may even convey meaning, such as reds or yellows for warning notification.
Colored polymer components can be produced from masterbatch concentrates (blended into natural polymer prior to molding or extruding) or pre-colored polymers via melt blending/compounding. The selection of one coloring method over the other may vary based on economics, secondary operations and end application.
Masterbatches or color concentrates provide an economical solution for long manufacturing runs of high volume parts. Sufficient setup time is required to ensure the concentrate is properly blended prior to and during the melt processing phase in order to achieve the desired color consistency from part-to-part. This investment may be offset by the economies gained from using a high proportion of unmodified polymer at a reduced price.
The use of masterbatches, however, can present several challenges. Metering un-dried masterbatches into hygroscopic resin may impart additional water, which may cause undesirable part appearance, processing and/or performance issues. Also, masterbatches require additional handling that may be inconsistent with the natural polymer to which it is added. This can result in potential production variability.
Concentrate pellets are also denser than the natural polymer pellets and tend to sift downward in the hopper, often leading to variable loading levels and color drifts throughout a production run. Although the use of color metering weigh feeders can minimize variation, it also requires additional equipment and production controls. This in turn, reduces the potential cost savings for short production runs.
Over the last year, a key challenge for compounders has been price. Materials, including additives, dyes and pigments, have been hard for compounders to find or have seen price hikes. Prices for some pigments and dyes have more than tripled, with Chinese tariffs playing a role in the increase. It could be 12 to 18 months before the market normalizes.