TOKYO - Honda Motor Co. has developed an innovative technique that can recycle plastic bumpers without removing the paint. Although other major automotive companies now reuse bumper material, some processes require that paint be removed using either chemical strippers or mechanical methods.
For example, Toyota has been recycling plastic bumpers using mechanical peeling, while Su-baru's process starts with chemical stripping of the paint.
With the Honda technique, the recycled material is used as the central layer in a three-layer laminated bumper in which all exterior portions of the bumper use virgin material.
Honda officials say they spent about $1 million to develop this process. According to spokesman Yo Harada in Honda's Tokyo office, ``there is no cost advantage to the new process, but it is more environmentally friendly because it does not require chemical peeling of the old paint.''
When the first facility builds up to maximum capacity this summer, it will be able to process 1,600 bumpers a month, according to Honda. Recycling is under way at the Kashiwabara plant of Honda-affiliate Yachiyo Industry Co. Ltd. using facilities that have been modified for this purpose, company officials said.
Honda is not using the method for production of new-car bumpers but is applying it to the production of replacement parts for use in collision repairs. The damaged bumpers that provide the required scrap material for recycling are accumulated by Honda dealers in Japan and collected by the company. Only Honda bumpers are being recycled by the firm.
Because all Honda bumpers are molded from the same mix of polypropylene and ethylene propylene rubber, recycling begins with material of known composition.
The recycling process begins with the crushing of scrap bumpers. After a water rinse to remove loose particles of dirt and road grime, the crushed material is formed into rice-like granules of uniform size.
Because the inclusion of paint in the mix tends to weaken the bumper material. Honda adds high density polyethylene to restore strength to the final product. Only a small amount of HDPE is used about one part in 20 by weight, according to the company.
The finished product combines a core section of recycled material ranging in thickness from 2.5-2.7 millimeters and a surface layer of virgin material that is 0.5-0.7mm thick, according to Honda.
Honda became the first automaker in Japan to set up a bumper recycling system in November 1991.
It now has facilities in every prefecture in Japan.
Honda has been working on its new process for three years at Honda R&D Co. Ltd. in Wakoshi, Japan; Honda Engineering Co., Ltd. in Sayama, Japan; and Yachiyo Industries. Fifteen Japanese patent applications relating to the new technology are pending.
Not all the problems faced by Honda on this project have been technical.
``It's very easy to ask [dealers] to recycle bumpers, but sometimes it can take hours to dismantle blinkers, rubber parts or steel reinforcing strips,'' Harada said.
Honda's more than five years' experience with bumper recycling has convinced management that, for bumpers and other parts to be easily dismantled, the issue must be addressed by manufacturers at the design stage. For parts that are large enough, Honda puts the name of the plastic material on the part at the manufacturing stage.
Honda also tries to standardize the materials used. Other car makers may use more than one type of plastic or add rubber or steel components to the molded bumper.
According to Honda, by designing parts that are easy to recycle, management aims to steadily increase the percentage of materials that can be recycled, thus easing the impact of the automobile on the environment.
