Welcome to the most environmentally friendly flame retardant plastic in the world.
Improving moldability and suitability for mass production
NEC is one of the most successful developers of technologies to improve the flame retardancy of plastics in the bioplastic field. This time, however, in the process of creating a new material that featured a much higher biomass ratio as well as the requisite flame retardancy, the team encountered an unexpected stumbling block. Dr. Iji recalls, "In order to raise the flame retardancy, we put several types of additive agents to plant-derived polylactic acid, which was the base resin we used for the bioplastic. We also used aluminum hydroxide, a safe endothermic agent and a component in soil, as the flame retardant agent to prevent toxic substances from being released when the plastic is incinerated. We found, however, that when we used this flame retardant agent by itself, the strength and moldability of the bioplastic were decreased. We therefore developed a completely new auxiliary agent for the flame retardant agent. This auxiliary agent reinforces the surface layer of the resin when it burned, preventing it from catching fire. The auxiliary agent took us four years to develop, and was developed using an original NEC technology."
One of the disadvantages of bioplastics is that they are less moldable than petroleum-based plastics, taking a lot longer to mold. To improve the moldability, therefore, NEC enlisted the collaboration of Kao Corporation, a leading company in consumer and chemical products. By using a new crystallization accelerant for the polylactic acid, crystallization could be sped up, and the molding time could be shortened, making it possible to mass produce bioplastic casings.
The biggest difficulty was developing a technology to compound and disperse the additive agents to create a good balance between flame retardancy, moldability, and thermal resistance. Dr. Iji recalls, "We tested and adjusted the mix of additives many times so as to maximize the properties of each type. However, we continually found that improving the practical properties of one additive had a negative effect on the properties of another." NEC and Kao Corporation worked together on this problem for over two years, before finally devising a technology that would increase the effectiveness of each additive agent without negatively affecting the others. "We were able to develop technologies that uniformly dispersed the additive agents within the polylactic acid by reforming the additive agents' surfaces and using high dispersion techniques. These methods significantly improved the effectiveness of each additive agent, which reduced the overall volume of required additive agents."
The key points of NEC's flame-retardant bioplastic
New bioplastic that NEC has developed contains more than 75% plant-derived resin (polylactic acid), and the amount of CO2 emitted while manufacturing it is less than half that emitted in conventional petroleum-based plastic manufacturing processes. Moreover, the successful development and practical application of new bioplastic-which includes no halogens or other toxic flame retardants, making it a plastic with one of the lowest impacts on the environment in the world-resulted from engineers pooling their knowledge and persevering in the face of a series of seemingly irresolvable problems. Dr. Iji looks back at the years he spent developing new bioplastic, "Materials engineers throughout the world may wonder how we managed to develop a practical bioplastic with a high biomass ratio as well as a high level of flame retardancy. We did it by challenging common assumptions in the industry about additive agents for bioplastics. We knew that we wanted to create an ideal bioplastic that contains a high biomass ratio, and we simply kept trying until we achieved our mission."
The resulting flame-retardant bioplastic will be used in the front panels of NEC's new business computer lineup due to be released in Japan in 2010.
Looking to the future, in addition to continuing development of bioplastics that rely primarily on cereals used for animal feed, NEC will also actively drive the development of new bioplastics that capitalize on non-edible raw materials such as cornstalks.
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