Liquid Color: The Right Tool for Many Jobs
With a recent spate of merger and acquisition activity focused on liquid color specialists, it is obvious that the value of liquid colorants and additives are an important product
form in the processing of molded or extruded polymers. A liquid product has some advantages over concentrates; but like any tool in a tradesman's box, liquid color is only effective when used in an appropriate context and with a firm understanding of its value
proposition.
Liquid colorant is a dispersion of pigments and/or dyes in specially selected liquid carriers which can be customized for the base resin and the user's process. Carriers are selected
to assure total compatibility of the colorant with the resin polymer. This promotes rapid and complete distribution of the liquid color concentrate into the polymer, leading to fewer processing problems.
It's important to recognize that the use of liquid colorant requires an accurate delivery and mixing system. As in any other process, cleanliness is very important in avoiding contamination
that can have a negative impact on the finished product's color and physical properties.
A Proper Context
Liquid colorants generally work well in production of commercial thermoplastics via extrusion, injection and blow molding. Advantages over concentrates can include:
- Higher letdown ratios
- Better thermal stability
- Reduced storage space
- Precise metering capabilities yielding better color consistency
- Comparative versatility in formulations
- Faster, cleaner color changeovers
Liquid must be viewed "not as a replacement to color resin concentrates, but as alternatives for specific manufacturing processes," according to Tim Workman, vice president of business
development for Plastics Color Corporation. Workman explains that PCC's new LiquiSol™ offering "is not a product… it's a full system designed to integrate liquid into a customers' operation."
Figure 1. Plastic Color Corporation's LiquiSol™ liquid colorant delivery system.
One example of a liquid colorant delivery system is pictured in Figure 1. A peristaltic pump (inset 1) feeds liquid colorant into the feed throat, or into an intermixer above the
feed throat, through a flexible, polymer tube (inset 2). The pump manipulates the outside of a flexible feed tube, pushing the liquid colorant through the tube assemblies. These pumps are extremely accurate and can move fluids with viscosities up to 12,000
CPS. Metering of color levels to very precise accuracy is achievable with no interruption in processing cycles.
Because the colorant is metered into the processing machine mechanically, the process requires minimal human interface. The colorant is easily and efficiently incorporated into
any molding or extrusion application. As depicted in the figure (inset 3), colorant can be supplied in a variety of packaging sizes to fit virtually any production and storage environment.
Other manufacturers are beginning to treat liquid as a systems-based solution as well. Performance and efficiency promises of liquid can only be achieved by first deciding if liquid
is right, then by engineering the right system for a particular application. Polymer manufacturers are becoming more discriminating in their application of liquid, letting the desired end product result guide them to selecting the colorant that will meet their
needs as efficiently and effectively as possible.
It's an industry shift that PCC welcomes, says Workman. "Since we manufacture and distribute both liquid and color concentrates and additives, we have no bias either way. "We just
want to help our customers understand liquid and decide which is best for their particular situation from a cost and use perspective. Our nationwide sales team is well-versed in all manufacturing and process techniques so they're uniquely qualified to help
our customers review their current operations and identify advantages liquid may offer.
Learn more about liquid for your operations..
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