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.