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.

Every year Sony uses several hundred thousand tons of plastic through its global operations. Currently vegetable-based plastics account for only 30-40 tons of that total. However, vegetable-based plastics are not the only recyclable materials used by Sony. While vegetable-based plastics are made from natural materials, reusable petroleum-based plastics are also classified as recyclable materials. Sony is committed to environmental initiatives and aims to increase its use of recyclable materials, including reusable petroleum-based plastics, to at least 12% of total materials by 2010. Of course, we aim to increase the percentage further after that date, which will require more research and development relating to vegetable-based plastics. Our ultimate goal is to create high-performance plastics that combine the characteristics of both vegetable-based plastics and petroleum-based plastics.

It is significant that instead of relying on existing vegetable-based materials developed by materials manufacturers, Sony conducts its own R&D projects. Unfortunately the physical properties of today's vegetable-based plastics are still not entirely satisfactory. To be able to use these materials more widely, we first need to improve their properties to achieve higher standards of durability and fire-resistance. We're also looking for next-generation alternatives to polylactic acid. Another focus of our research is the search for a source of polylactic acid which can replace corn starch. We need to secure a source that is not used by humans as a food source. As an opinion leader in this field, Sony remains committed to an active program of research relating to vegetable-based plastics.