It is known for panels to include embedded color features that have outer surfaced that lie flush with outer surfaces of the panels they are embedded in. One current process for producing such products includes forming a feature on a slush mold surface then casting a charge of powdered plastic against the mold and a back surface of the color feature.

One example of this process is disclosed in United States Patent No. 5,648,030 issued July 15, 1997 to Pemberton et al. According to Pemberton et al., the color feature is formed by first placing a stencil on the mold surface then casting a plastic powder into the stencil. The stencil is then removed before the second charge of plastic is cast. The formation of the feature on the mold ties up molds for an excessive period of time and is labor intensive. In addition, to accurately cast plastic powder exclusively into the confines of a stencil on a mold surface requires additional tooling and/or labor to prevent the powder from falling on other portions of the mold.

Methods for applying pre-formed features in panel surfaces are disclosed in United States Patent Nos. 4,519,972 and 5,498,307 issued to Stephenson. The Stevenson'307 patent disclosed a rotomolding process that includes affixing features to mold surfaces using an adhesive. In the Stevenson'972 patent, features are affixed by burnishing.

What is needed is simple, quick, inexpensive and non-labor intensive process for embedding a color feature into the surface of a molded panel.

In accordance with this invention a process is provided for embedding a color feature into a surface of a plastic shell, wherein the feature is made from plastic material and deposited onto a mold before molding the plastic shell. The mold comprises a mold surface having a shape complementing a desired shape of the surface of the plastic shell to be molded. A first pre-formed feature of plastic material is deposited on the mold surface. The first pre-formed feature is adhered to the mold surface by heating the mold surface. A charge of plastic is then applied against the mold and a back surface of the first pre-formed feature. The resulting shell is then cooled and removed from the mold surface with the first pre-formed feature embedded in the surface of the shell. Designs formed on the shell surfaces in this way are durable in that they are not as susceptible to being worn off as are surface coatings such as paint. Because the design is embedded in the shell, colors and/or color shades that distinguish the features from the surrounding shell surface are more likely to last the life time of the shell. A pre-formed, embedded feature produced by the inventive process is distinguishable from the surrounding shell surface only by visual differences such as color or shade and therefore provide more design freedom for stylist. The lack of surface relief also makes the shell surface easier to clean.

According to another aspect of the invention, the first pre-formed feature of plastic material has a material specification that is the same as a material specification of the plastic material applied against the mold. By using material to form the feature that has the same material specification as the shell, the feature material adheres better to the shell material and provides a uniform appearance with the shell.

According to another aspect of the invention, a plurality of pre-formed features of plastic material are provided, with each of the plurality of features being shaped to form a composite design when placed next to each other in a predetermined pattern. The plurality of pre-formed features. are then deposited in predetermined positions on the mold surface in the predetermined pattern to form the composite design. The plurality of pre-formed features are then adhered to the mold surface by heating the mold surface. The charge of plastic is applied against the mold surface and the back surfaces of the respective pre-formed features and heating the mold surface to application temperature. The resulting shell is then cooled and stripped from the mold surface with the plurality of pre-formed features being embedded in the surface of the shell in positions forming the composite design.

To better understand and appreciate the invention, refer to the following detailed description in connection with the accompanying drawings: FIG. 1 is perspective view of a pre-formed feature adhered to a mold surface of a mold in accordance with the invention process; FIG 2 is a cross-sectional side view of the pre-formed feature and mold of FIG. 1 with an attached charge box containing plastic material in accordance with the inventive process ; FIG 3 is a cross-sectional side view of the pre-formed feature, mold, charge box and plastic material of FIG. 2 being rotated in a rotary molding process in accordance with the invention process; FIG 4 is a front perspective view of a pre-formed feature embedded in a plastic shell according to the inventive process; FIG 5 is a magnified fragmentary view of the pre-formed feature, mold and plastic shell material of FIG. 3; FIG. 6 is a magnified fragmentary view of an alternative pre-formed feature construction disposed on a mold and covered with plastic shell material according to the inventive process; A mold for embedding a decorative color feature into a surface of a plastic shell made from plastic material applied against the mold surface is generally indicated at 10 in FIGS. 1-3,5 and 6, is provided. The mold 10, preferably a thin nickel shell mold, comprises a surface 12 having a shape complementing a design shape of the surface of a plastic shell or shells to be formed.

A first pre-formed feature of plastic material, as shown at 14 in FIGS. 1-5, is then provided. The first pre-formed feature 14 of plastic material may be formed by die cutting the feature 14 from plastic sheet material. Alternately, the first pre-formed feature 14 of plastic material may be formed by casting plastic material into a feature mold 10 shaped to complement the desired shape of the feature. The feature would then be remove from the feature mold and placed on the mold surface 12 of mold 10.

In either case, the plastic material of the feature 14 preferably has a material specification that is the same as a material specification of the plastic shell material 16.

The first pre-formed feature 14 is deposited in a desired position on the mold surface 12. The first pre-formed feature 14 is adhered to the mold surface 12 by heating the mold surface 12 to a temperature above ambient before depositing the first pre-formed feature 14 on the mold surface 12. A molding process may then be completed.

As is best shown in FIGS. 2 and 3, the molding process includes the applying, preferably by casting, of a charge of the plastic shell material 16, preferably thermoplastic in powder or microsphere form, against the mold 10, and the back surface of the first pre-formed feature 14. The mold surface 12 is heated to molding temperature either before or after applying the charge of plastic shell material 16 against the mold surface 12. At the molding temperature the mold 10 transfers sufficient heat energy to the plastic shell material 16 to at least partially melt the particles of plastic shell material 16 to the point where they bond together to form a shell 20. The resulting shell 20 is then cooled and removed from the mold surface 12 with the first pre-formed feature 14 embedded in the surface of the shell 20 and visible on an outer surface 22 of the shell 20 as shown in Figure 4. Any suitable molding process may be used to form the shell 20 around the pre-formed feature to include the processes disclosed in United States Patent Nos. 4,882,173; 4,895,690; 4,983,906 and 5,072,325 which are assigned to the assignee of the present invention and are incorporated herein by reference.

As shown in FIG. 6, other embodiments may include the provision of a pre- formed feature 24 of plastic material that is formed to include a layer of heat activatable adhesive 26. In this case, the pre-formed feature 24 is deposited on the mold surface 12 with the heat activatable adhesive layer 26 at least partially contacting mold surface 12, it may or may not be necessary to heat the mold 10 to molding temperature to activate the adhesive layer 26.

Rather than providing only a single pre-formed feature, a plurality of pre- formed features of plastic material may be provided. FIGS. 1 and 4, for example, show second and third pre-formed features at 30 and 32, respectively. The pre- formed features 14,30,32 may differ from one another in optically discernible characteristics such as shading and coloring or as shown in FIGS. 1 and 4, by pattern.

The plurality of pre-formed features 14,30,32 are shaped to form a composite pattern 34 in the form of an image, a textual message, a design or the like, when the features are placed next to each other in a predetermined array. As shown in FIG. 1, the plurality of pre-formed features 14,30,32 are deposited in their respective predetermined positions on the mold surface 12 in the predetermined pattern to form the composite design. The plurality of pre-formed features are then adhered to the mold surface 12 by heating the mold surface 12 to a temperature above ambient as described above. The mold surface 12 is then cooled and a molding operation is carried out.

Similar to the single-feature process described above, the molding operation includes applying the charge of plastic against the mold surface 12 and the back surfaces 18,36,38 of the respective pre-formed features 14,30,32 and heating the mold surface 12 to molding temperature. At molding temperature the mold 10 transfers sufficient heat energy to the plastic shell material 16 to at least partially melt the particles of the shell material 16 to the point where they bond together to form a shell 20. The resulting shell 20 is then cooled and removed from the mold surface 12 with the plurality of pre-formed features being embedded in the surface of the shell 20 in positions forming the composite design.

The resulting design is essentially as durable as the shell 20 it is formed in.

Because the process forms a single, uninterrupted smooth surface across the pre- formed features 14,30,32 and the surface of the shell 20, the design is resistant to wear and is distinguishable for the surrounding shell surface only by differences in optical characteristics between the pre-formed features 14, 30,32 and the shell 20.

I intend this description to illustrate certain embodiments of the invention rather than to limit the invention. Therefore, I have used descriptive words rather than limiting words. Obviously, it's possible to modify this invention form what the description teaches. Within the scope of the claims, one may practice the invention other than as described.