Japan developed bioplastics superior to PLA from cashew shells

September 2nd, NEC Corporation has developed a bio-plastic material that uses a proportion of plant-based vegetable raw materials that is as high as 70% of the total mass. Some of the new bioplastic properties such as toughness, impact resistance and heat resistance are no less than polylactic acid. The company plans to continue to develop bioplastic materials research in the field of electronic equipment materials and strive for practical application in 2013. The main raw materials for the new bioplastics are cellulose in plant stems and cardanol in cashew nut shells.

A specific production step is that cellulose acetate cellulose having increased activity with acetic acid and cardanol having increased activity by production and reforming react in an organic solvent. This results in a heat-fusible plastic. During the reaction, substances with increased density were added. The company did not specifically disclose the details of the additive, but it has been learned that it is a substance that has highly reactive functional groups on the benzene ring.

The company believes that it is also good for cardanol, and it is guaranteed in terms of yield. It is a raw material that can be stably supplied. Cellulose acetate is a practical bioplastic. It is mainly used for making photo and film films, as well as polarizing films for displays. However, in order to obtain plasticity, it is necessary to add a large amount of plasticizers derived from petroleum, and it is also necessary to increase the strength and heat resistance of the additives, so the plant degree is about 40%. In addition, due to its lower water resistance and lower water absorption, it is not suitable for use in electronic products, and its use is limited to the aforementioned film materials. The new material uses plant-derived cardanol instead of plasticizers, so it can achieve up to 70% plant growth. In addition, compared to PLA, which is widely used in bioplastics, although the vegetative degree of PLA itself is 100%, when it is used in the construction of parts, in order to improve strength, fluidity, etc., petroleum-derived plastics are added. The actual plant degree in the case is about 25%. Therefore, NEC believes that the new material is superior to PLA in terms of vegetative degree. However, there are still some problems with the new materials in terms of fluidity and flame retardancy. In the future, if additives are used to improve these problems, the degree of plant life may decline. On the other hand, research on the extraction of acetic acid used for the reformation of cellulose from plants is also underway. If it is successful, it is expected to increase the vegetativeness to nearly 90%. Cardanol is a phenolic substance, and linear hydrocarbons bind in the vicinity of the hydroxyl group. Due to the presence of this part, the material is rendered hydrophobic and flexible. It is now used as a brake adjustment material for automotive brakes, coatings, and additives for insulating materials. However, the current state of the art does not use all the cashew nut shells. Most of the shells are used as fuel.

NEC will further strive to improve the physical properties of the material and establish the production technology. Currently only laboratory-level synthesis reactions, it is also planned to develop processes that can be efficiently synthesized. It is envisaged to cooperate with material manufacturers in mass production.