DAVOS, SWITZERLAND - One of the most difficult problems in recycling auto parts has been the separation of paint and coatings from large plastic parts so that the parts can be reused for similar parts. Hiroshi Yamamoto, senior engineer at Fuji Heavy Industries Ltd., a major part supplier to Subaru Motors Ltd. of Tokyo, claims the firm has found a way to strip paint and coatings from auto bumpers, the largest single plastic part on cars, which could facilitate bumper recycling.
Speaking at the Recycle '95 Worldwide Recycling Conference in Davos, Yamamoto said the Fuji system involves technology that eliminates the need for chemicals, heating or other material-altering treatments. The process is mechanical and solvent free, requiring no secondary processes.
``The roller press method we have developed is a simple technique in which bumpers are cut into three sections, and fed through a modified set of rollers, which strip the paint and coatings,'' he said. ``The materials produced in this way are sufficient for bumper to bumper recycling in both physical properties and appearance.''
After the paint is removed, the plastic can be ground, gran-ulated and remolded into bumpers in combination with virgin materials without loss of tensile strength or material adaptability to new coatings. The paint film residue can then be burned.
Yamamoto said the results of Fuji's testing showed paint residue on the processed material was visually undetectable and did not affect the plastic's mirror or grain qualities.
He said a commercial-volume roller stripping plant could be set up for about 6 million yen ($72,600).
``This method is sufficiently feasible even for a small volume'' of 6,600-11,000 pounds per month, Yamamoto said.
Other methods require a processing volume of 110,000-154,000 pounds per month to pay off.
He said the process is feasible for other painted or coated parts.
Fuji's testing indicated success was dependent on bumper specifications, the character of the paint and coatings, and collision-resistance qualities.