Toray Industries, Inc. today announced that it has successfully developed a plant fiber-reinforced polylactic acid (PLA) plastic with improved heat resistance, rigidity1) and moldability by compounding2) cellulose-based plant fibers3) with PLA. Able to withstand heat up to 150°C, which is the highest level in the world for biomass plastics, the newly developed plastic has double the rigidity of existing PLA plastics and has achieved significant reduction in the time required for molding. Furthermore, the Company succeeded in radically improving the properties of biomass plastics by accomplishing superior exterior of plastic mixed with plant fiber. The Company intends to promote the product in wide-ranging applications including automobile parts, electrical and electronic parts, civil engineering and construction materials and furniture.
Until now, companies and research institutes have been focusing on development of technology that blends plant fiber as reinforcement material for improving the strength of PLA. However, there were limitations to deploy such plastics in practical applications due to reasons such as inferior exteriors of molded products caused by uneven mixing, tendency of PLA to decompose at molding, long molding cycle4) in injection molding and low heat resistance. However, with an injection molding method that is superior in mass production capability, the new technology will enable the manufacture of PLA plastic products possessing heat resistance and rigidity equivalent to or better than existing petroleum-based plastics.
This technology was developed in cooperation with Showa Marutsutsu Co., Ltd. (headquarters: Higashi-Osaka City, Osaka) and Showa Products Co., Ltd. (details same as those of Showa Marutsutsu) by combining Toray’s proprietary resin compounding technique with the newly developed technology that accelerates crystallization.
The features of the new technology are as follows:
1. Development of proprietary resin compounding technology
In addition to solving the problem of PLA’s tendency to breakup at the time of molding, the Company’s proprietary compounding technology to combine PLA and plant fiber enabled the improvement of exterior and rigidity of molded products. The technology also allows raising the ratio of plant fiber in the plastic to maximum 50% through uniform mixing and micro-dispersion of the fiber and enables the molding of foam products.
2. Development of technology that accelerates crystallization of PLA
In pursuing the acceleration of crystallization to the maximum based on the interaction of PLA polymer and plant fiber, the Company succeeded in development of a revolutionary technology to accelerate the crystallization speed to 50 times that of plain PLA and 10 times the most recent improvements in technology. This high crystallization capability has not only significantly reduced the molding time but also enabled the realization of heat resistance of 150°C through the reinforcement effect from uniformly dispersed plant fiber and rigidity that is double the existing products.
PLA is a biomass polymer that is manufactured by polymerizing the lactic acid produced by fermenting starch contained in sweet corn and other plants. With its “carbon neutral” feature that helps conserve the depleting oil reserves and control amount of carbon dioxide emissions, PLA has great potential as a material with low environmental burden contributing to the prevention of global warming. While improvements in heat resistance and rigidity as well as in suitability for mass production have been the issues that held back the spread of PLA, the development of this technology is expected to significantly expand applications of PLA.
Under its corporate slogan “Innovation by Chemistry,” Toray has identified the four important segments of ‘information, telecommunications and electronics,’ ‘automobile and aircrafts,’ ‘life science’ and ‘environment, water and energy’ as important growth areas and aims to expand its advanced materials business with focus on these areas. In the environmental field, the Company is engaged in the development of products such as PLA that are based on non-petroleum raw materials. It also aims for business expansion of environment-friendly products such as Ecodear*5) its universal brand for PLA products, by pursuing innovative research and development that employs its own advanced technologies.
Terms |
| 1) |
Rigidity: A physical quantity that shows the degree of resistance to deformation of molded goods. A higher resistance to deformation under a certain level of force means that the molded product has higher rigidity. |
| 2) |
Compound (kneading): Compounding of toughening agents and additives into a base resin in order to achieve targeted performances and functions. The technology discussed in the press release employs melt compounding that kneads melted resin and additives. |
| 3) |
Plant fiber: Fiber obtained from the stem, leaf, skin, seed, etc. of plants. The main constituent is cellulose and forms the raw material for apparel and paper. |
| 4) |
Molding cycle: A unit time from the start through the end of one injection molding. A shorter molding cycle means better productivity. |
| 5) |
Ecodear*: A universal brand for fiber, resin and film products based on plant-based plastic polylactic acid (PLA) that combines Toray’s unique technologies. |
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