Get products out faster with the right additives.

Engineered fillers, blowing agents, and processing aids if you're facing a productivity squeeze, a pinch of one of these ingredients might help you get more pounds or shots per hour out of your machines. Two of these are not normally thought of as productivity enhancers. One is a special filler that speeds cooling of the melt, the other is a blowing agent that is used to promote flow rather than to reduce density. In the third case, new processing aids boost output and reduce costs in PE and PP film, pipe, and cable extrusion and blow molding.

1 Engineered Fillers for Polyolefins

Beyond resin extension or property enhancement, mineral fillers are finding a new role as productivity aids. Fine-particle, surface-treated calcium carbonates in pure or masterbatch form have been developed specifically to increase output of polyolefin blown-film extrusion and injection or blow molding. At modest loadings of 10-20%, the filler does not greatly change product properties but does boost thermal conductivity so that the melt cools and solidifies much more quickly. Major proponents of this technology are film and bag producer Heritage Plastics and filler supplier ECC International.

Film & coating run faster

Heritage pioneered the use of calcium carbonate in blown film about 12 years ago. It buys fine-ground calcium carbonate from suppliers such as ECC, Georgia Marble, J.M. Huber, and Omya. Heritage makes a pellet concentrate for its own use and for sale to other processors. Designated HM10, it contains 75% of a 1-micron calcium carbonate in an LLDPE carrier. It's aimed at LLDPE blown film and, more recently, has been used in HMW-HDPE. Another recent development is an LDPE version of the concentrate, called H-Tec, for extrusion coating.

Frank Ruiz, technical director, says Heritage has about three dozen film customers using its mineral filler. He estimates at least 500 million lb/yr of film is made with mineral reinforcement - primarily for trash bags.

Ruiz says 10-20% filler increases LLDPE blown-film output by 20-40% through faster bubble cooling. In recent work with HMW-HDPE, addition of 15% filler concentrate provided a 15% increase in output rate. Similar results have been achieved in LDPE extrusion coating. Says Ruiz, "With 30% calcium carbonate, you increase the coating output rate by 30%, you can run as thin as 0.25 mil with no web tear, and adhesion of LDPE to most substrates is enhanced."