The special challenges of special effects

Wellness Innovations was seeking an elegant, special effect color that would give a slick new appearance to the Variable Power Thumper Massager, so molder Performance Plastics (Toronto) teamed up with Clariant Masterbatches to create one.

“Clariant supplied us with different color for Wellness Innovations to evaluate, and the graphite with silver specks was a perfect fit with the product design,” says Lou Coppa, president of Performance Plastics.

“With our expertise in engineering resins, we weren’t afraid to tackle a special effect colorant in an already challenging base polymer (polycarbonate) for the two piece housing.”

Screw design was especially important to get the right effect, says Coppa. “A low compression screw should be used with polycarbonate in general, but even more so with the metal fleck because it tends to plasticize more evenly. You have less shear and more even distribution of particles.”

“One of the drawbacks to working with this type of special effect is that you can get build-up,” notes Coppa. “But that was easily handled by lowering the screw speed and the injection rate because of the way these molds are gated.”

Clariant sales representative Gary Mercer explains that the speckled effect was created by incorporating a silver coated fibre. “Processing the fibre into the polycarbonate is tricky. One of the challenges is to maintain particle size because polycarbonate is such a stiff resin.”

Because of the metal coated fibres, the material had to pass UL testing from spark and discharge.

But all challenges aside, the new color is a success. “I’ve seen a lot of colors, and this one catches my eye,” says Coppa. “When you get the right combination of colors and effects, it makes a difference like night and day. It makes you want to buy it.”

Clariant Masterbatches 800-265-3773