A METHOD FOR THE APPLICATION OF A COAT OF PAINT OR THE LIKE TO A PREDETERMINED PORTION OF THE SURFACE OF AN ARTICLE, PARTICULARLY A MOTOR VEHICLE BUMPER

Abstract: The method comprises the steps of covering the surface of the article (1) with a film (2) of plastics material which adheres thereto, then cutting the film along a line which constitutes the outline of the said surface portion (7), removing the covering film from that portion, then applying the coat of paint in known manner, and removing the remaining portion of the film from the surface.

Description: The present invention relates to a method for the application of a coat of paint or the like to a predetermined portion of the surface of an article. The invention particularly concerns the painting of motor vehicle bumpers of plastics material, the external surface of which must have at least one portion provided with a coat of paint so as to define at least two adjacent zones having different surface properties, for example different colours. According to known techniques, the zone intended to receive the paint is delimited by masking of the adjacent surface portion, which is carried out manually with the use of paper and adhesive tape. Masking by the application of a peelable varnish is also known. These operations, however, require both a considerable expenditure on labour and, in the case of the prior application of a peelable varnish, considerable plant costs connected with the installation of application booths and drying ovens. The preamble of claim 1 is based on technology known from GB-A-2 158 368. The strippable film is applied in the form of paint which after drying constitutes a strippable film. The object of the present invention is to provide a method which is particularly simple and inexpensive both in relation to labour costs and to plant costs. For this purpose, the subject of the invention is a method for the application of a coat of paint or the like to a predetermined portion of the surface of an article, particularly of a motor vehicle bumper, comprising the steps of: covering the surface with a film of plastics material which adheres thereto, cutting the film along a line which constitutes the outline of the said surface portion and removing the covering film from this portion, applying the coat of paint to the portion in known manner and removing the remaining portion of film from the surface. The film of plastics material having adhesive properties towards the surface of the article is applied by means of vacuum coating in a manner similar to "skin pack" technology. Further details and advantages of the method according to the invention will become clear from the detailed description which follows with reference to the appended drawings, provided by way of non-limiting example, in which: Figures 1, 2 and 3 are schematic sections which show three separate stages of the method. With reference to the drawings, a motor vehicle bumper, for example, of moulded plastics material such as polypropylene, is indicated 1. It will be understood, however, that the innovative principle of the method can be applied to any kind of material constituting the article which is to receive the paint. A film of thermoplastic material constituted, for example, by an olefin polymer, particularly polyethylene and ethylene-propylene copolymers, is indicated 2. The film is supported at its edge by a frame 8. One face 2a of the film of plastics material has adhesive properties towards the surface of the bumper 1, for example, by means of the previous application of a glue effected by conventional spreading or manufacturing techniques. In order to carry out the method, the bumper 1 is supported with the surface to be painted facing outwardly, by means of a support member 3 which is similar to a half die for vacuum thermoforming and is provided with internal ducts 5 which put the surface of the support member facing the inner surface of the bumper into communication with a vacuum pump. The surface of the bumper which is to be covered with the film 2 is degreased beforehand in order to assist the adhesion of the film. This adhesion is achieved by the application of a subatmospheric pressure through the ducts 5 and possibly by the simultaneous heating of the film to its softening temperature by means of heating elements 4, for example, infrared radiators. Figure 2 shows the bumper 1 with its external surface completely covered with the film 2. It is particularly important to achieve complete adhesion of the covering film, avoiding the formation of bubbles. After adhesion of the film to the surface of the bumper has been achieved, the film is cut by means of a cutting tool 6 along a predetermined line constituting the outline of the surface portion 7 of the bumper which is intended to receive the paint, and the covering film is removed from that portion. The painting of the portion 7 can then be carried out by means of a conventional cycle, after any flame treatment of the surface, which is particularly useful if the bumper is of polypropylene. The term "paint" as used in the present description means the any applied coating layer. After the painting of the surface portion 7, the covering film 2 can easily be removed from the remaining surface portion so as to obtain a painted bumper which has a clear outline between the painted portion 7 and the paint-free portion.

Claims: A method for the application of a coat of paint or the like to a predetermined portion of a surface of an article, particularly a motor vehicle bumper, comprising the steps of: covering the surface with a film (2) of plastics material susceptible to adhere thereto, cutting the film along a line which constitutes the outline of the said surface portion (7) and removing the covering film from this portion, applying the coat of paint to the portion in known manner and removing the remaining portion of film from the surface, characterised in that the adhesion of said plastics film to said surface is caused by supporting the article by means of a complementary support member (3) provided with internal ducts (5) which put the outer surface of the support into communication with a source of subatmospheric pressure, and applying a subatmospheric pressure through the ducts until adhesion of the film to the surface of the article is achieved. A method according to Claim 1, characterised in that it includes the step of heating the film (2) to its softening temperature at the stage of its application to the surface of the article. A method according to any one of Claims 1 to 2, in which the article is constituted by a motor vehicle bumper.

Inventors: BELTRAMO, CARLO, VERDUCI, FORTUNATO
Applicants: FIAT AUTO S.P.A.
Application year: 1989
Main classification: B05D1
IPC codes: B05D1, B05B15