In 2000, Kenji Moriwaki was placed in charge of development at Mazda's Technical Research Center. It was the first time that he had responsibility for R&D work, and he smiles broadly as he thinks back on that time. "Despite the technical difficulties, I was very pleased to be given complete control over the work for the first time. I felt, 'OK, let's go for it,' and that I would give it my best shot."
That was about 10 years ago. Around that time, the Japanese government started tightening recycling regulations and companies were forced to further develop recycling technologies. From the outset, rather than just complying with the regulations to use resources more effectively, Mazda went a step further and set the goal of reusing bumpers that had been damaged out in real-world driving*1 as raw materials for bumpers on new vehicles.
Due to the difficulty of processing collected material, recycled material is generally of a lower quality than the original material. This is why damaged bumpers have previously been used in parts of the vehicle that are not visible, such as underbody covers. By contrast, bumpers on new vehicles are in very prominent positions on the vehicle, so it would not be practical to use recycled material for that application. However, if Mazda could recycle a large plastic component like bumpers to the high quality standards required for new vehicle bumpers, it would be a huge technical step forward, and be a way to address environmental issues by cutting CO2 emissions and using resources more effectively. So there was a lot to be gained by pursuing this goal.
- *1Bumpers collected when damaged or broken bumpers are replaced during repairs.
In general, bumper recycling starts with pulverizing the recovered bumpers into small fragments called pellets. Once impurities such as the paint on the surface have been removed, the pellets are combined with new material to make raw material for new vehicle bumpers. The crucial factor in this process is ensuring that the recycled and new materials are of equivalent quality, and the key to doing this is how much of the paint is removed. If paint gets mixed in with the recycled material, it cannot be used for new vehicle bumpers because the strength of the plastic declines, and it also prevents a perfect finish from being achieved when the bumper is painted. First, scraping the paint off was attempted.
Mazda's partner in bumper recycling technical development is a plastics recycling company called Takase Gosei Kagaku Corporation, which is located in the same part of the country as Mazda's head office, in Hiroshima Prefecture. Prior to this project, Takase had already been developing its own technology for removing (paint) coating from pellets. It started when the plant manager, Tomomi Takase, unexpectedly discovered that paint peels off at a set temperature. Thinking that 'this could work!' Takeo Takase then set about designing his own machine. He kept on refining the process, pushing hard with such determination that the contractor working on the improvements nearly gave up. The result was a sophisticated paint removal technique that nobody else has been able to match.
As Kenji Moriwaki recalls, "The level of Takase Gosei Kagaku's technology was extremely high. It was able to remove the paint from almost all the pellets. But there were still some pellets mixed in that contained paint, which didn't quite meet the level of quality needed in material used for new bumpers."
To achieve the beautifully smooth, mirror-like finish of a new vehicle bumper, the accuracy of the paint removal had to be further improved. With development at an impasse, Moriwaki talked to his boss about the problem and was given the name of a company that would never have occurred to him otherwise.
Satake Corporation developed Japan's first-ever power-driven rice polishing machine in 1896 and is still thriving today as the world's leading manufacturer of food processing machinery. Rice polishing is a technique that removes the outer layer of rice grains. Some thought there might be a way the same technique could be used to remove paint. With this advice in mind, Moriwaki paid Satake a visit.
Satake's head office may be in the same prefecture, but the request from Mazda – a company in an entirely different industry – came right out of the blue. Satake, however, gladly took up the challenge. As Nobuhiro Higashi at Satake Corporation recalls, "We were also actively engaged in environmental protection activities, such as developing environmentally friendly products using biomass resources. So we were by no means averse to cooperating in developing a technology that would contribute to recycling efforts."
However, a number of trials were repeated using rice-polishing technology to remove the paint from the plastic pellets without achieving the results hoped for. At one point, Moriwaki became discouraged, feeling that it was unreasonable to think that they would be more successful in removing paint than the techniques used by Takase Gosei Kagaku. Many people wondered if they should discontinue the trials; then Satake offered him a chance to look at the other machines it manufacture.
What caught the eye of Moriwaki and his colleagues was an optical sorting machine that removed impurities such as stones and defective grains from harvested cereals. This machine, they were told, ensured that only perfect rice grains made it to the table. This was the moment when their whole approach changed, from focusing on removing the paint to simply sorting the pellets so that only suitable pellets were chosen. If only pellets without residual paint were collected, a high-quality product could be ensured. In the end, Mazda requested Satake to adapt this technology for use with Mazda's efforts.
Takase Gosei Kagaku's technology strips off the paint, and Satake's optical sorting technology sifts out any pellets that still have any residual paint.*2 Using a fusion of Takase Gosei Kagaku's extensive experience, Satake's unique technology and the inspiration provided by Moriwaki and his team, Mazda has overcome some major obstacles to create "bumper-to-bumper recycling," the automotive industry's only method of continually using recycled materials as the raw material for new vehicle bumpers.
The paint removal technology for bumper-to-bumper recycling developed by the three companies was awarded the 16th Katashi Aoki Technology Award (sponsored by the Japan Society of Polymer Processing) in recognition of the progress it has achieved in polymer processing technology. It was also selected from 2,382 other candidates as one of the '240 Landmarks of Japanese Automotive Technology' by the Society of Automotive Engineers of Japan as a technology worthy of being passed on to future generations.
Kenji Moriwaki commented, "In the future, increasingly high levels of performance will be demanded from plastic components, and our goal was to develop a way to both recycle materials and improve performance."
All three companies had different roles, yet worked together toward the same goal of a sustainable future.
- *2The pellets removed by the optical sorting machine are reused in products such as underbody covers to eliminate any waste.