1. Field of the Invention
The present invention relates to a method of making and inspecting an in-mold coated article.
2. Background Art
Techniques for manufacturing molded articles with painted, or coated, surfaces have been developed in which the paint, or coating, is applied to a mold surface prior to molding the article. A polymeric resin is supplied to the mold, the molded article cures, and bonds to the in-mold coating. This coating application process is commonly referred to as an in-mold coating process.
Manufacturing high quality parts, such as automotive interior components, may require assurance of complete in-mold coating coverage. If the molded substrate is colored to match the color of the in-mold coating, it is difficult to confirm the integrity of the in-mold coating coverage. It is easier to detect voids or gaps in the in-mold coating when the molded substrate that is applied over the in-mold coating is of a different color than the in-mold coating. If the in-mold coating and underlying substrate are of contrasting color, a simple visual inspection is all that is required to detect gaps or voids in the in-mold coating.
A color matched substrate may be used to improve color match and reduce the amount of in-mold coating required to manufacture parts that are of the desired color. It is difficult to detect unpainted areas on articles that are made of a color matched polymer that matches the in-mold coating. Color matching the substrate to the in-mold coating also assures long-term performance. Even if the substrate is color matched to the in-mold coating, it is important to achieve a complete coating with the in-mold coating to assure adequate performance in long term exposure testing without fading or color changes occurring either in the in-mold coating or the molded substrate.
There is a need for a simple and cost effective method for detecting areas on an article having an in-mold coating applied to the surface when the underlying molded substrate and the in-mold coating are color-matched.
Applicants' invention addresses the above problems and needs as summarized below.
According to one aspect of the present invention, a method of making an article is provided in which an in-mold coating is applied to a mold. A fluorescent dye is mixed with a polymeric forming mixture to form an ultraviolet enhanced mixture. The ultraviolet enhanced mixture is sprayed over the in-mold coating and then cured to form a coated article. The coated article may then be exposed to a source of ultraviolet light and inspected to identify the areas on the coated article that are not covered by the in-mold coating.
According to other aspects of the method of the present invention, the step of applying the in-mold coating may be performed by spraying the mold with the in-mold coating. A polymer composition such as a polyurethane mixture may be compounded as a mixture of polyol and isocyanate. The polyurethane mixture may further comprise a pigment that colors the polyurethane mixture to match the in-mold coating color.
According to another aspect of the method of the present invention, the article made by the method may be a vehicle interior trim part.
According to other aspects of the method of the present invention, the step of mixing the fluorescent dye may be performed by injecting the dye into a spraying system of polyol, isocyanate and a color pigment. The step of spraying the UV-enhanced mixture may be performed by a spray gun that has a mixing chamber for mixing the dye, polyol, isocyanate and a color pigment. The quantity of fluorescent dye added to the polyol component of the mixture may be in the amount of 0.025 to 0.2% by weight of the polyol.
According to another aspect of the present invention, an article manufacturer is provided that comprises a polyurethane layer having a fluorescent dye mixed into the layer. An in-mold coating is applied to the polyurethane layer in the mold. The coverage of the in-mold coating may be inspected by exposing the article to a source of ultraviolet light.
According to other aspects of the invention as they relate to the article of manufacture, the polyurethane mixture may be a mixture of polyol and isocyanate. The polyurethane mixture may further comprise a color pigment that colors the polyurethane mixture to match the in-mold coating color. The article made by the method may be a vehicle interior trim part.
According to another aspect of the invention, an interior trim part for a vehicle may be made according to a process wherein a fluorescent dye is mixed with a polyurethane forming mixture to form an ultraviolet enhanced mixture. An in-mold coating is first applied to the mold and then the ultraviolet enhanced mixture is sprayed over the in-mold coating. The ultraviolet enhanced mixture is cured to form a coated article and then may be exposed to a source of ultraviolet light that allows the coated article to be inspected to identify areas on the coated article that are not covered by the in-mold coating.
According to other aspects of the invention, the step of applying the in-mold coating may be performed by spraying the mold with an in-mold coating. The polyurethane mixture may comprise a mixture of polyol and isocyanate and further may comprise a color pigment that colors the polyurethane mixture to match the in-mold coating color. The step of mixing the fluorescent dye may be performed by injecting the dye into a spraying system with the polyol, isocyanate and a color pigment. A florescent dye may be added to the polyol in the amount of between 0.025 to 0.2% by weight of the polyol. A spray gun may be provided that has a mixing chamber for mixing the dye, polyol, isocyanate and a color pigment.
These and other aspects of the present invention will be better understood in view of the attached drawings and the following detailed description of the illustrated embodiment.
Referring to
Referring to
A molded article 28 is formed by spraying, or otherwise applying the isocyanate 20, polyol 22 and UV dye are combined to form an ultraviolet enhanced mixture upon the surface of the mold cavity 12. A colorant may also be added to the polyol for color matching to the in-mold coating. When completed, the molded article 28 is removed from the mold cavity 12.
Referring to
Any voids 32 can subsequently be identified and corrected by applying additional in-mold coating or paint that is compatible with the in-mold coating to the portion of the molded article 28 with the voids 32. The in-mold spray process may also be reprogrammed to provide better coverage on subsequently manufactured articles. The isocyanate 20 and polyol 22 may also have a pigment or colorant added thereto to match the color of the substrate formed by the polyurethane forming component to the in-mold coating.
While embodiments of the invention have been illustrated and described, it is not intended that these embodiments illustrate and describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention.