Organic and Other Polymer Developments

Toray has also developed what is claimed to be the world s first flexible PLA film for wrapping and other applications. PLA may also be alloyed with high Tg PC and a non-halogen flame retardant to produce a material which is used to make notebook computer casings. The microdispersive alloying with PC results in a compound with good heat resistance, mouldability and durability. 

Other manufacturers of PLA based products iuclude NEC which uses it as the main component of its bioplastic which has the world s best flame retardance for a product of this type. This has been obtained without the use of halogenated or phosphorus-based flame retardants. The proprietary property-modifying additives employed in the bioplastic by NEC include inorganic heat adsorbents, high-flow modifiers and impact modifiers. The material conforms to UL 94 5V standard thus enabling it to be used in a wide variety of electronic products including personal computer housings. 

NEC has also reinforced PLA with a 20% loading of Kenaf, a natural plant fibre from Hibiscus cannabinus L., to obtain a high strength reinforced bioplastic. The fibre reinforcement is claimed to raise the polymer s deflection temperature under load from 67 °C to 120 °C and increases bending modulus from 4.5 GPa to 7.6 GPa. The fluidity and moisture resistance of the polymer are said to be unaffected. NEC is reports that the heat resistance and strength of the reinforced polymer exceed that of glass-filled ABS. 

In partnership with Unitika, NEC has developed the reinforced PLA case for the DoMoCo N701i ECO mobile phone case. NEC claims that the material used achieves a biomass ingredient ratio of 90% which is the highest level of any bioplastic used in electronic devices. To achieve this figure the partners have added a biomass-based flexibiliser and reinforcement filler to secure the simultaneous benefits of heat resistance, high fall impact durability and ability to be moulded. 

Elsewhere in Japan, Mitsubishi and Sony have teamed up to develop a flame retardant PLA resin which uses a UL 94 [1] V-2 rated aluminium hydroxide RoHS compliant flame retardant. The new material is claimed to be as strong as ABS and, by using additives and by adjusting moulding parameters, Sony is able to process it to make front panels for its stand-alone DVD players using conventional 

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