Ampacet Designs Masterbatch to Minimize Warpage when Changing Color in Polyolefins
Oct 31, 2006
TARRYTOWN, NY -- Ampacet has introduced two masterbatches that help control warpage in polyolefins. The products, Ampacet 103003 and 103004, contain a unique nucleating agent that controls warping better than standard nucleating chemistries, including talc, calcium carbonate, aromatic carboxylic acid salts and phosphate ester salts. In addition to lower warpage, studies show these masterbatches reduce cycle time as much as 10 percent by raising the crystallization temperature.
Warpage and other processing issues can arise when a molder changes part color, because some organic pigments affect polymer crystallization rate. Ampacet's database shows this often occurs, for instance, when green or blue phthalocyanine pigments are introduced. The new masterbatches are designed to offset the crystallization effects such pigments impose.
Injection molded parts undergo warpage due to differential shrinkage in the machine and transverse directions. It is believed that the performance of the new nucleating agent is due to the plate-like shape of its particles, which creates a more isotropic shrinkage than the needlelike particles of traditional nucleators.
"The new masterbatch is most effective if it is designed into components from the beginning," says Doug Rusk, senior technical service engineer. "It provides more uniform shrinkage and promotes faster crystallization, which helps molders minimize warpage when running a part that calls for the successive use of different colors."
"In terms of process efficiency, molders tell us they want to run their machines at the same ratios regardless of the color used," says Rich Novomesky, business unit manager. "We designed Ampacet 103003 and 103004 to help them achieve this goal, and so keep one more variable out of the processing equation."
Ampacet 103003 is for use with polyethylene base resins and Ampacet 103004 is for use with polypropylene. Both grades have an initial suggested letdown ratio of 1 percent, although the actual amount required in the final part may exceed this. Ampacet can also add the nucleator in these masterbatches directly to a color masterbatch. All grades are FDA compliant and so can be used in food packaging.
About Ampacet
Ampacet Corporation is a global masterbatch leader and offers the broadest range of custom color, special effect, black, white and specialty additive masterbatches for extrusion, molding and a multitude of other processes and applications. Founded in 1937, it now employs more than 1,500 people and has revenues exceeding $650 million. Headquartered in Tarrytown, N.Y., Ampacet Corporation operates technical and color development centers and manufacturing sites throughout the Americas, Asia and Europe.
