|
Polylactic acid (PLA) has a substantial growth rate globally in packaging materials and in other plastics products, where performance demands are not too high. Application in electronics goods is however, limited by its heat resistance and mechanical strength. One way of improving the properties of PLA has been to blend it with other plastics.
Amid growing awareness of environmental issues such as resource depletion, a mobile phone has been introduced in Japan that uses a crop-derived polymer composite for its casing, called Foma N701iECO. It uses polylactic acid (PLA) resin reinforced with kenaf fibers to replace oil-based plastics for the case. K enaf is a member of the hibiscus family and related to cotton and okra. It grows 3-9 times faster than most plants achieving heights of around 4 metres in 4-5 months. Its moisture resistance was increased by basing the composite on Unitika's commercial PLA product Terramac, drop impact resistance was increased by adding a biomass-based flexibiliser and a reinforcing filler specially developed and mouldability was improved with additives that were jointly developed by NEC and Unitika.
BASF has alloyed NatureWorks' polylactic acid with its own petrochemically-sourced Ecoflex biodegradable copolyester for mobile phone casings. In terms of sustainability, Ecovio® offers an additional advantage: The polylactic acid used in its manufacture is largely carbon dioxide-neutral when composted.
Sharp has developed a compatibiliser to enable PLA to be blended with PP from recycled electronics equipment.
Fujitsu has succeeded in developing a prototype mobile phone chassis using a new bio-based polymer. Fujitsu has also developed a new bio-based polymer that retains the heat resistance and moldability of their previously developed bio-based polymer, while improving impact resistance by 50%. PLA has been blended in a 50:50 ratio with an unspecified 'non-crystalline plastic' with a high glass transition temperature and flame-retardant technology for a notebook computer. Fujitsu and Toray have combined polymer-alloy and flame-retardant technology to develop a bio-based polymer, which Fujitsu introduced in the world's first notebook PC with a full-size chassis made with bio-based polymer. In Fujitsu's latest notebook model available in Japan, 93% of the entire chassis is made from bio-based polymer. |
