By Bill Bregar
SENIOR STAFF REPORTER
Published: October 22, 2014 1:35 pm ET
Updated: October 22, 2014 1:36 pm ET

Image By: Unilever
Unilever is using the Trexel MuCell foaming process to reduce the weight of some bottles.

CHICAGO — Foaming is a good alternative to thin-walling for reducing plastic use in consumer goods packaging, according to a Unilever plastics expert.

Packaging forges consumer perception of staples like shampoo and detergent, said Frederic Dreux, Unilever’s global packaging capability leader for rigid plastics. If the package gets too thin — from traditional thin-walling to reduce weight — it can give the consumer a feeling the product is not high quality, he said, during a presentation at the SPE Blow Molding Conference.

“So we tried to decouple from thickness, not to impact the rigidity of the package,” Dreux said.

Unilever partnered with MuCell Extrusion, the foaming technology company, and Alpla, a major supplier of extrusion blow molded bottles to the consumer products company, he said.

“Foaming offers weight reduction while maintaining the ‘consumer properties’ of the product,” he said at the conference, organized by the Blow Molding Division of the Society of Plastics Engineers. The event ran Oct. 5-7 in Chicago.

Dreux described foaming in the extrusion blow molding process. The parison, composed of three layers of HDPE, uses regrind. The key, he said, is that the foamed structure must be maintained after the parison is extruded — and when blowing multiple parisons on the same cycle.

The MuCell Extrusion process requires a special barrel and screw. A dosing unit injects gas into the melt in the barrel. MuCell Extrusion is a wholly owned subsidiary of Zotefoams plc in Croydon, England.

Dreux said that partnerships with other companies to develop new products can work well. But before you begin, it’s important to define and agree on how the companies will own which specific parts of the innovation, he said.

Dreux said foaming bottles to reduce plastics use is part of Unilever’s Sustainable Living Plan, to reduce its waste footprint by 50 percent by 2020. The company uses recycled plastics and bioresins, he said.

Earlier this year, Unilever announced it was foaming its bottles for Dove Body Wash, cutting their use of plastics by at least 15 percent.

Dreux explained the complexity of measuring “green” metrics in consumer products. For example, the shampoo bottle represents only a small fraction of the greenhouse gases when you take a shower, while the warm water accounts for 95 percent, he said.