INDIANAPOLIS - Thermoformed polypropylene has grown in Europe as a thin-gauge food packaging material and will become more popular in the United States, according to speakers at ANTEC '96. ``Polypropylene will go head-to-head with polystyrene in some markets'' such as medical products and disposable food-service items, said Laurette Hoover, principal at Harborside Research Group in Salem, Mass.
Hoover urged thermoformers in the market to buy new equipment to consider a machine's ability to change materials.
In food service, Hoover said demand for disposable packaging continues to increase because of the proliferation of drive-through and walk-up restaurant counters and outlets found in airports, colleges - even in hospital waiting rooms.
But competition is greater, too. That means restaurants can boost profit only by squeezing out costs.
Hoover was one of four people presenting technical papers at a May 9 thermoforming session at the Indianapolis meeting of the Society of Plastics Engineers.
Another speaker, Nicola Macauley, said, ``Polypropylene is making considerable inroads in these markets in the United Kingdom.''
Macauley reported on research on thermoformed PP sheet at Queen's University of Belfast in Northern Ireland.
``The semicrystalline nature of polypropylene can offer a whole host of advantages to the processor,'' she said, including excellent chemical and moisture resistance, a high melting point and low density.
Unfortunately, that same structural makeup makes PP difficult to process because of its narrow temperature processing range.
The Belfast researchers examined the impact of adding nucleating agents - particles such as silica, talc or pigment - to extruded PP sheet.
The agents speed crystallization, producing small rounded shapes, known as spherulites, that enhance processing and boost properties of the final product, such as transparency and improved wall thickness distribution, Macauley said.