Surface treatment of plastic

Citation

Hollingum, J. (2001), "Surface treatment of plastic", Industrial Robot, Vol. 28 No. 2. https://doi.org/10.1108/ir.2001.04928bad.012

Surface treatment of plastic

Surface treatment of plastic

Keywords: Surface treatment, Plastics, Robots

Applicant: Kansai Paint Company Ltd (JP)Patent number: US5269820Publication date: 14 December 1993Title: Method for surface treatment of plastic material and apparatus used therefor

Using a treating solution which is easy to dispose after use, the surface of a plastic material is treated so that the treated surface has good adhesion to a coating film to be formed thereon. An aqueous dispersion containing an abrasive which is harder than a plastic material to be surface-treated, is pressurized to about 1.0-200 kg/cm² and then is injected onto the surface of said plastic material through an injection nozzle. An airless spray gun having said injection nozzle is supported by a polyaxis type or articulated type robot. Thus, the surface of a plastic material is ground and converted into a rough surface and then coatings are applied thereon. The feature of the present invention lies in treating the surface of a plastic material by a particular means, prior to applying coatings to the surface.

In the present invention, the plastic material to be surface-treated includes plastics used in, for example, the outer panels (e.g. bumper, fascia, fender) of automobiles, such as polyolefin, polypropylene, polyurethane, polyamide, ABS (acryl-butadiene-styrene), AES (acryl-ethylene-styrene), polyester, PPO (polyphenylene oxide), PC (polycarbonate), unsaturated polyester, PPO/PC alloy, ABS/PC alloy and the like. Each of these materials is moulded to an intended shape and size prior to the surface treatment. The abrasive can be appropriately selected depending upon the kind of the plastic material to be surface-treated. Basically, it must be harder than the plastic material; when it is softer than the plastic material, the surface grinding according to the present invention is difficult, making it impossible to achieve the object of the invention. In the present invention, it is necessary to inject the abrasive-containing aqueous dispersion onto the surface of the plastic material, allow the abrasive to collide with said surface, thereby grind and remove the surface layer of the plastic material to form a new rough surface. It is preferable to remove the surface layer uniformly in a specific thickness of 1m or more, particularly 1-100m. It is also necessary that the surface of the plastic material after grinding be a rough surface and not mirror surface. The surface of the plastic material, which has been treated according to the present method, is coated with ordinary coatings for plastics, according to an ordinary method.