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large blow molding machines producing housings for flter tanks. After several trials, the company chose Riverdale's Pump- in-a-Drum system combined with a gravimetric blender from Maguire Products. In an October 2013 presentation at SPE's Annual Blow Molding Conference, Scott Pugh, business unit manager for Hayward's sand-flter product, discussed the company's blow molding color-change experience with liquid colors vs. pellet concentrates. He cited these savings: • Mold changes went from 93 min to 33.8 min.; • Head tooling changes from 330 min to 150 min; • Purge compound processing time: 120 min to 0 min; • Scrap due to color streaks: 55 parts on average down to 18; • Total changeover time: 14.55 hr to 4.9 hr; • Total cost per changeover: $3086 to $800. Addressing the faster changeovers, Pugh explained that 80% of the color dispersion takes place before the resin enters the extruder, and 100% dispersion as soon as the resin mixture hits the melt zone. Also, viscosity is reduced and the melt moves more easily downstream. This allows lower processing temperature and mini- mizes the buildup of colorant in stagnant areas of the accumulator head. Currier Plastics, Auburn, N.Y. (curri- erplastics.com), an injection and blow molder of packaging for personal care, healthcare, cosmetics, household chemi- cals, and hotel amenities, has delved into liquid color for various projects and sees it as promising for more in the future. The company uses ColorMatrix systems. Starting with experience with liquid colors in blow molding, Currier cites such advantages as more homogeneous disper- sion of color than with pellet concentrates and the ability to introduce colorant directly into the feed throat with only adapter plates and nozzles required. Currier also says peristaltic pumps ensure very consistent and reliable color from shot to shot compared with auger and disc feeders for pellet concentrates. Currier also likes the fact that liquid- pump controllers are inexpensive and user-friendly, especially when intro- ducing regrind into the system. Company sources also appreciate reduced storage space and say the metering equipment has come a long way, resulting in an extremely clean process. Despite higher cost/lb for liquid colorants, Currier says there are often opportunities for cost savings due to extremely low letdown ratios. Also barrels and screws clean very easily compared with color pellets, reducing the need to pull screws to remove color buildup on fights. In addition, the material does not need to be dried. Currier also speaks favorably of the dual-feeding system that allows the co-introduction of more than one liquid additive into the feed throat, such as a color and a UV inhibitor, slip agent, or regrind. Currier says cost is not necessarily the main reason it uses liquid color. The company cites cases where a customer is willing to pay more due to the quality and operating benefts of liquid colorants. Currier is also looking to make the transition to liquid color in its injection molding, noting that many of its custom programs already have been switched from pellet concentrates and more are in progress. Cobra Plastics, Macedonia, Ohio (cobraplastics.com), a maker of aerosol caps, is also aiming to make a transition to liquid color from ColorMatrix. Says Cobra's Jerry Bialko, v.p. of operations, "As we fnd the right balance between cost and consistency of our products for our customers, we will utilize liquid color where it makes sense. We are exploring opportunities for liquid color for other overcap styles and we are currently requesting color matches. We are in the preliminary stages of utilizing liquid color, but we are optimistic on what we have seen so far. There are great improve- ments in liquid-color metering in the past couple of years, which allow for quick and efcient color changes." Liquid color can lower costs by 10% to 40% compared with solid colorants, depending on the application. Riverdale Global is setting up local "satellite" facilities in places with high concentrations of processors to facilitate just- in-time liquid color distribution and expedite service Riverdale Global Proprietary Color Delivery System Savings Bottom Line Energy Zero Landfll Riverdale HQ Perth Amboy, NJ Single Source Pigment Dispersions Returns for Refll Your Facility Free Delivery Before Milling After Milling Milled Pigment Riverdale Global Satellite Facility Purge Time Cycle Time Warehouse Space Liquid New Time Old Time Pellet Riverdale's Local Solution to Liquid-Color Supply 42 DECEMBER 2014 Plastics Technology PTonline.com ADDITIVE S