sector continues, especially in PLA production. CSM subsidiary Purac recently commissioned a
75,000 tonnes/year PLA monomer plant in Thailand, claiming that its scale of production will improve pricing while the new technologies it is using will allow PLA to match the thermal resistance of PS and PP and shortly the impact resistance of ABS. Meanwhile, the decision by Thailand’s PTT Chemical
to take a $150 million stake in the Natureworks PLA operation opens the way for the company to expand its presence in Asia. Natureworks, which currently has just one manufacturing plant in the US, says it plans to set up a second manufacturing operation in Thailand to come online in 2015. In a separate move, NatureWorks has partnered with bio-based succinic acid producer BioAmber in a new joint venture – AmberWorks – to develop a line of improved performance bio-based polymers based on compounds of PLA and PBS (polybutylene succinate). And US-based bioplastics group Cereplast has
acquired a site at Assisi in Italy where it plans to install 50,000 tonnes of annual manufacturing capacity for its bioplastic and bioplastic blends, taking its global capacity to 86,000 tonnes/year. Performance and processibility of biodegradable
bioplastics are critical areas for development as, while shortfalls in either can be accommodated by processors, both carry a cost above the bulk resin premium. This has proved to be one of the key drivers towards bio-based versions of traditional polymers, according to Braskem marketing and marketing intelligence manager Rodrigo Belloli, who says the immediate appeal of traditional biodegrad- able bioplastics to brand owners often fades once detailed investigation into the cost/value balance begins. “Traditional bioplastics such as PLA,
starch-based, biodegradable polyester and PHA face hard challenges regarding cost,
physical performance, processing and environmental issues,” he says. On the cost side, Belloli says the resin price premium
is typically pushed further by less obvious factors such as higher density (PLA has a density of 1.25 against 0.91 for PP), investment in process development and machine modification, and how the product fits into existing recycling or disposal infrastructure. Taking these costs together with uncertainty over the value the new material will deliver to the brand leaves many brand owners unwilling to risk adoption, he says. Switching to a bio-based version of a traditional
plastic such as PE or PP, however, reduces the risk to a simple cost premium on the resin, says Belloli. “As they [bio-based commodity polymers] are drop-in replace- ments, all the other characteristics remain the same - the same processibility, same performance, recyclabil- ity and product weight. At the end this means much less effort and investment in developing biopolymer applications,” he says.
Bioplastics with tradition Production of traditional plastics from bio-based feedstocks is not in itself new – castor oil has been used as a feedstock for a number of speciality polyamides for many years. Extending bio-based feedstocks to the more everyday resins such as PE, PP and PET is an obvious move, accord- ing to Dr Sally Humphreys, chair and
AMI consultant at the Green Polymer Chemistry conference (which next takes place on 19-21 March 2013 in Cologne,
Germany – see http://bit.ly/GPC2013). “The plastics industry has spent over a hundred years developing materials for long term critical applications like polyeth-
ylene pipes and barrier packaging, both of which conserve food and water for the world’s rapidly expanding population.
June 2012 | COMPOUNDING WORLD 47
Above left:
PLA granules “grown” by
Natureworks Above right:
Natureworks is planning a second PLA
manufacturing plant, which it will build in Thailand
Left: Coca-Cola says more than 10bn bottles have been produced with its PlantBottle PET resin