[UPDATE] Interviews with Engineers - The World's First Products Made from Vegetable-based Plastics

Sony has been a pioneer in the development of plastics made from vegetable-based materials and has led the electronics industry in the use of vegetable-based plastics to manufacture product cases. How were these vegetable-based plastics developed? We asked one of the engineers involved to talk about the background of these materials and the challenges encountered on the path to their development.

My background is polymer research. Some examples of my work include the development of materials for optical disc substrates, tape media and materials supporting the creation of intricate patterns on semiconductor chips. I first encountered and began to evaluate polylactic acid around 1990. Polylactic acid was seen as a promising material, and I was examining its potential for products. I subsequently began to carry out research relating to aspects of environmental technologies, including material recycling, lead-free solders and water pollution prevention technology. At the heart of Sony's environmental technology is the concept of using materials derived from biomass (plants) in products. Past successes include the use of limonene (a type of oil extracted from oranges) to facilitate the recycling of styrene foam, and the use of biomass-based carbon as electrode material. After discussions among our research team members, we decided to research whether or not polylactic acid could be used in products built to be highly durable. Around 1998, we began to work toward this goal in earnest.

Polylactic acid has a long history and has been used widely in the manufacture of biodegradable plastics. Unfortunately, it is fragile, vulnerable to heat and inflexible, making it unsuitable for creating product casings. It also requires special care to prevent degradation during use.

To use polylactic acid in the manufacture of product casings, we knew we'd have to overcome all these problems. However, our research team members were all professionals with excellent problem-solving skills and extensive experience in the enhancement of physical properties. We were confident we could overcome the challenges. Through continued trial and error, we discovered that aluminum hydroxide could be used to make the material fire-resistant, and that strength and durability could be improved by adding rubber and a hydrolysis regulator. We also found that excellent malleability could be achieved by adding pigments. The result was a vegetable-based plastic that met quality conditions for use in products. At the time, not even industrial material manufacturers were aware of the potential of polylactic acid for use in creating product casings.

A new Walkman launched by Sony in 2002 was the world's first product with a casing made from vegetable-based plastics. The most difficult aspect of our work on this product was not the development of the vegetable-based plastic, but the process leading up to its use in actual products. Because these materials had never been used before, our product developers had many doubts and concerns. We visited them repeatedly to brief them about the importance of using vegetable-based plastics and convince them of their suitability by showing them data relating to their reliability, cost, suitability for mass-production and other factors. This can perhaps be characterized as a process of changing perceptions within Sony.

Color reproduction characteristics represented another challenge. When the pigments added were changed for each color, the physical properties of the materials also changed. When no suitable pigment was available, we had to find one through a repeated trial-and-error. For each color, we also assessed the material to ensure that it met the required quality standard. In some cases it was very difficult to reproduce the stipulated color accurately, but eventually we were able to achieve the colors sought by the designers.

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