Injection molding machine manufacturer Nissei Plastic Industrial Co. Ltd. has developed a range of presses especially for the processing of polylactic acid (PLA), a plastic derived from plant starch. The machines, with molds and processing technology supplied by a leading Japanese molding consultancy, are marketed especially for the processing of high-heat grades of PLA, which to now has been very problematic.

Although demand growth for PLA has been strong, the material to now generally has not often been specified for applications requiring high heat resistance. Injection molding grades of general-purpose (non heat-tolerant) PLA generally are used only for applications requiring stability up to 60°C.  Heat-tolerant PLA can remain stable at temperatures up to 120°C; however, the additives and/or fillers used to raise the material's heat stability also affect its flow characteristics, making it difficult to fill complex or deep-cavity tooling and also leading to poor mold release.

Nissei (Nagano, Japan), working with injection molding consultant Michio Komatsu, believes it now can offer a system able to process even highly heat-stable PLA grades for mass-market applications. The two companies' combined experience led to development of Nissei's new N-PLAjet range of machines, which are available in electric and hybrid (electric/hydraulic) versions. The systems already are offered in Japan and, starting next month, also will be marketed in the U.S. Komatsu has filed a patent in the U.S. for the mold and processing technology required to form heat-resistant PLA parts.

The PLA package is offered across 19 injection molding machines, from Nissei's electric NEX Series (16.5-507 tons) to its hybrid FNX Series (89-501 tons) presses. The N-PLAjet systems are marketed with everything a processor needs to get started molding PLA. Mold temperature control, mold inner pressure/temperature direct control system, air blow system, and valve gate (hot runner mold) capable interface are part of the package, as are a production license and the intellectual property for building the molds. Nissei hopes for demand initially from processors serving the markets for disposable and returnable products, such as food container, medical, cosmetic, sundry, and stationary industries. 

Molders keen to learn more about these N-PLAjet units have the chance later this month to see in action at the Plastec Midwest tradeshow in Rosemont, IL, scheduled for Sept. 28-30. During the event Nissei plans to run one of its NEX80-12E (88 ton) machines processing a family mold (container and lid) for a vial holder, using a nanocomposite-filled PLA. Plastec is organized by Canon Communications LLC, parent company of PlasticsToday, IMM and MPW.—[email protected]