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GE gives plastic bottle recycling a new spin

ChemicalProcessing.com
08/25/2006

A new method for making certain polymers promises to devour extensive amounts of post-consumer polyethylene terephthalate (PET) waste, claims GE Plastics, Pittsfield, Mass. The company is launching a polybutylene terephthalate (PBT)-based polymer, Valox iQ, and a PBT/polycarbonate alloy, Xenoy iQ, that use the wastes as raw materials. Novel chemistry enables 85% of the PBT-based polymer’s content to come from the wastes, says Tim Dummer, the company’s Southfield, Mich.-based, global marketing director for automotive new markets.

The established approach to making PBT involves using butanediol (BDO) and either terephthalic acid or dimethyl terephthalate, he notes. Instead, GE has developed a process that breaks down PET waste into an undisclosed monomer mix that can be reacted with BDO. The level of BDO needed is cut to 15%, which is much less than that required with conventional technology, he adds.

By relying upon recycled materials, the approach reduces CO2 emissions by at least 1.7 kg/kg of resin and saves as much as 8.5 bbl of crude oil/1,000 kg of resin, claims GE. If the technology had been used for all PBT production in 2005, it would have consumed 562,000 metric tons of PET waste, or the equivalent of 22.5 billion bottles, according to the company.

This environmental benefit doesn’t come with a hefty price for resin, notes Dummer. Valox iQ is competitive economically, he says, selling for only a small premium over conventional PBT, whose applications are being targeted. Japanese automakers and their “Tier 1” suppliers are likely to be early adopters, starting in the fourth quarter, he says, probably followed by use in consumer electronics.

“From a practical point of view, the new materials are drop-in replacements,” he claims. Valox iQ offers better flow than conventional PBT, but incurs a minor loss in heat-deflection temperature, which additives can compensate for, he adds.

The polymers now are being made in Asia, but compounded globally, with  North America likely to be the next area for  production. There’s no reason that GE eventually couldn’t completely migrate from conventionally producing similar resins, says Dummer.

The drivers

The new products stem from an initiative GE Plastics began about two years ago to examine its manufacturing methods with the aim of developing polymers whose production posed less environmental impact. That, coupled with the ready availability of a consistent, high-quality supply of waste PET were key drivers behind the new process.
Basically, the process starts with cleaned and flaked post-consumer PET wastes, such as water and soda bottles, photographic filmstock and the like. While Dummer won’t reveal process details, he says that the route is straightforward and can be easily retrofitted to existing production sites.

GE is exploring other opportunities for the PET-waste-based chemistry platform, he notes. Indeed, the company now is developing a thermoplastic elastomeric copolymer using the process for the polyester building blocks. High-heat and transparent versions are possibilities, he adds.

GE also is looking at making the next generation Valox iQ resin even more environmentally friendly, by replacing petroleum-derived BDO with bio-based material.

“That’s a logical extension,” says Dummer, adding that the investigation still is at an early stage.