Looking around any room, you’ll likely see numerous items benefiting from the addition of color. From food and beverage containers, to electronics casings, to the ticking clock on the wall, all of these items have included a colorant process in their manufacturing. Liquid colorants in particular are an asset in production.
Liquid color is a mix of pigments or dyes in specialized liquid vehicles, which are compatible with virtually all polyolefin, styrenic and engineering resin systems.
Low letdown ratios are achieved by loading various pigment volumes into the liquid vehicle. Pigments are then broken down into particles, which are wet-out in the resin vehicle to increase the uniformity, opacity and intensity of the original pigment. This high concentration of color results in low letdown ratios: for opaque colors, normally one part color to 100 parts resin; for transparent colors, as little as one part colorant to 1,000 parts resin, etc.
By utilizing an entire range of specialized vehicles, this eliminates effects on physical properties and promotes rapid and complete distribution of concentrated liquid color into the resin.
At Color Master, single-pigment base colors are maintained in stock for rapid, low-cost blending in small or large quantities. Additive concentrates such as anti-static agents, slip aids, chemical blowing agents and UV stabilizers and absorbers may be incorporated as well.
As far as color injection, precision metering pumps are equipped with a three- or six-roller peristaltic head which compresses the outside of a flexible feed tube, forcing liquid color through the tube, and are capable of metering as little as one gram of material per cycle of viscosities up to 20,000 CPS. Output can be adjusted in milligram increments, permitting fine-tuning of color levels without processing interruption. Because the colorant is metered into the processing machine mechanically, the system requires little supervision.
The colorant feed tube can be connected to injection and extrusion machines in either of two locations: immediately below the hopper feed throat, or into a special groove machined into the base of the barrel feed section. The liquid-to-liquid interface of colorant-to-resin in the plasticating barrel promotes rapid mixing and complete distribution of the color, resulting in uniform coloration.
Complete color changeovers can be done in minutes by changing to a different colorant feed tube and purging the barrel of the original resin color. Using a liquid purging compound, purge waste and changeover times can be further reduced. Natural resin in the hopper never requires emptying or drying, and the peristaltic pump head requires no cleaning. And accidental spills are easily cleaned since liquid color washes away with water.
For more information about our liquid color capabilities in the plastics industry, please feel free to contact us online.
Color Master, Inc 