MATERIALS

Field of the Invention

The present invention relates generally to the field of extruded decorative trim pieces and more particularly to extruded decorative trim pieces for use in automotive vehicles and for other purposes.

Background of the Invention

The invention is particularly suited for forming trim strips and decorative strip components for vehicle bodies and will be described with particular reference thereto; however, as will become apparent, the invention is capable of broader application and can be used for forming a variety of strip-like products from thermoplastic materials.

Decorative and protective trim strips formed from thermoplastic materials are in widespread use in the automotive industry. The strips may be used for body side moldings, for front and rear quarter panels, and side doors. They must meet exceptionally high standards for color uniformity and color match. Moreover, they must have distinctive end shapes to meet manufacturing requirements for customer appeal.

Such strips have been made by both injection molding and extrusion processes. Both of these processes have certain advantages and disadvantages. Injection molding is slow and expensive. It is, however, possible to provide injection molded strip having shaped molded ends in a length accurately calculable to that length which is required.

For example, when injection molding such strip products, the effective rate of production is closely tied to the number of die cavities available. Moreover, dies for such products are relatively cumbersome and expensive. Additionally, the cycle time for such products tends to be relatively long because the strip products are flexible

and very difficult to remove from the mold cavities and handle without damage until after they have cooled significantly. Furthermore, there is a potential for peeling of the decorative film since it is taped to a surface of the injection molded strip product which would reduce the esthetic appearance of the decorative strip products.

U.S. Patent No. 5,226,998 issued to Few discloses a process for making a vehicle molding wherein a continuous strip of a thermoplastic material is extruded and a continuous decorative laminate is secured onto the upper surface of the strip to form a continuous substrate. However, since the decorative laminate is provide on the upper surface of the molding, there is a potential for the laminate to peel.

An extruded molding is much less expensive to produce and may be extruded onto a carrier strip or without any carrier strip. A variety of approaches have been used in an attempt to provide contoured and shaped ends on extrusion formed decorative trim pieces. For example, separately molded end pieces have been bonded to the main extruded center section including a decorative film. However, when using this technique, a noticeable joint line generally results between the molded end sections and the extruded center section reducing the esthetic appearance of the final decorative trim product. Furthermore, the extra molding step increases the cost for providing decorative trim pieces by this method. Additionally, the color matching and appearance generally differs between the end sections and the center section.

Thus, it is desirable to provide decorative trim products that can be produced more cost effective than prior art decorative trim products.

Furthermore, it is desirable to provide more esthetically pleasing decorative trim products in comparison to prior art decorative trim products.

Summary of the Invention

In accordance with the invention there is provided, a trim piece comprising a co-extruded first thermoplastic material; a decorative film in contact with the co- extruded first thermoplastic material; and a co-extruded second thermoplastic material

in contact with the co-extruded decorative film and the co-extruded first thermoplastic material for enclosing at least a portion of the co-extruded decorative film.

In accordance with a further embodiment of the invention the co-extruded first thermoplastic material and the co-extruded second thermoplastic material are made from a same thermoplastic material.

The first and the second thermoplastic material can be a rigid or a flexible material.

In accordance with a further embodiment of the invention, the co-extruded first thermoplastic material is for forming a base of the trim piece and the co-extruded second thermoplastic material is for forming a skin of the trim piece.

In accordance with yet a further embodiment of the invention, the co-extruded first thermoplastic material further comprises a filler material for supporting the trim piece.

In accordance with another embodiment of the invention, the decorative film is made from a polyester film, an aluminized polyester film, a Mylar™ film, a bright strip film, a colored strip film, or a chrome strip film. The polyester film can comprise aluminum or chrome.

In accordance with the invention, there is further provided, a decorative automotive trim piece having a proximal end and a distal end comprising a base for attachment to an automotive vehicle; a decorative film provided on the base; and a skin for covering at least a portion of the base and at least a portion of the decorative film, wherein said skin extends over the base for concealing base and edge portions of the decorative film for securing the decorative film.

In accordance with a further embodiment of the invention, the base is made from a first thermoplastic material and the skin is made from a second thermoplastic

material. If desired, the first and the second thermoplastic material are made from a same thermoplastic material.

In accordance with another embodiment of the invention at least one of the proximal end and the distal end is tapered.

In accordance with yet a further embodiment of the invention, the base is a relatively rigid base.

In accordance with another aspect of the invention, there is provided, a method of making a decorative trim piece comprising the steps of co-extruding a first and a second thermoplastic material from an extrusion die and providing a decorative film between the first and second thermoplastic material for forming a co-extrudate, passing the co-extrudate while still in a plastic state through a pair of cooperating wheels for shaping a cross-section of the decorative trim piece, said step comprising defining a periphery of the decorative trim strip, and providing a cut-line in the second thermoplastic material for defining an outer dimension of a cut-out portion; and allowing the decorative trim piece to cool.

In accordance with a further embodiment of the invention the method further comprises the step of removing the cut-out portion along the cut-line for exposing the decorative film to a show surface of the decorative trim strip.

In accordance with another embodiment of the invention, the pair of cooperating wheels comprises an idler wheel and a forming wheel. Furthermore, the forming wheel comprises a molding cavity having two blades.

In accordance with yet another embodiment of the invention, the extrusion die has an outlet with an area at least substantially as great as a desired cross-sectional area of the decorative trim strip.

In accordance with a further embodiment of the invention, the co-extrudate is extruded onto a foil carrier.

In accordance with another embodiment of the invention, the method further comprises the step of removing the foil carrier from the cooled decorative trim piece presenting a substantially flat surface.

In accordance with yet another embodiment of the invention, the method further comprises the step of providing an adhesive to the substantially flat surface for allowing the decorative trim piece to be attached to an automotive vehicle.

In accordance with a further embodiment of the invention, the step of allowing the decorative trim piece to cool comprises the step of passing the decorative trim strip through a cooling chamber.

In accordance with yet another aspect of the invention, there is provided, an elongated decorative molding comprising a decorative show surface defined by a window portion in a skin provided on a base having a decorative film sandwiched therebetween, said decorative film showing through the window portion. In accordance with an embodiment of the invention, the decorative film can be made of a polyester film, an aluminized polyester film, a Mylar™ film, a bright strip film, a colored strip film, a chrome strip film, or any other suitable decorative film.

Brief Description of the Drawings

Exemplary embodiments of the invention will now be described in conjunction with the following drawings wherein like numerals represent like elements, and wherein:

Fig. 1 shows a schematic cross-sectional view of a co-extrudate on a foil carrier;

Fig. 2 shows a schematic cross-sectional view of a co-extrudate passing through a forming wheel including two blades;

Fig. 3 shows a schematic cross-sectional view of a decorative trim strip product in accordance with the invention;

Fig. 4 is a schematic top plan view of the decorative trim strip according to the invention;

Fig. 5 is a schematic bottom plan view of the decorative trim strip according to the invention.

Fig. 6 is a schematic presentation illustrating the apparatus and method of making decorative trim strip products in accordance with the invention;

Fig. 7 is a schematic presentation of a section of the apparatus presented in Fig. 6 showing a more detailed view of the idler wheel and the forming wheel to illustrate how the decorative trim strip products are molded; and

Fig. 8 shows a more detailed view of a section of the forming wheel of Fig. 7;

Detailed Description of the Preferred Embodiments

The invention is generally concerned with forming decorative trim strip products from any suitable thermoplastic material and combinations thereof. For example, rigid and flexible polyvinyl chloride, thermoplastic olefin, thermoplastic polyolefin, thermoplastic polyurethane, and thermoplastic rubbers have been used successfully. The invention is not intended to be limited to a particular choice of materials. Obviously, those skilled in the art will become aware of other materials which could equally well be used as the description proceeds.

Turning now to Figs. 1-5, more detailed views of the decorative trim strip product in accordance with the present invention are presented.

Fig. 1 shows a schematic cross-sectional view of a co-extrudate 22 on a foil carrier 24. The co-extrudate 22 includes a first thermoplastic material serving as a

base 52 and a decorative film 54 covered with a second thermoplastic material serving as a skin 56. The first and second thermoplastic materials are selected in dependence upon the desired properties of the decorative trim strip product to be made. If desired, the first and second thermoplastic materials are the same. As can be seen from Fig. 1, skin 56 curls underneath decorative film 54 so as to ensure that the decorative film 54 is more firmly held by the skin 56.

It is appreciated that the invention is not intended to be limited to the type of decorative film. Some examples of decorative film to be used in accordance with the invention are a polyester film, an aluminized polyester film, such as a Mylar ^τ film, a bright strip film, a colored strip film, a chrome strip film, or any other decorative film.

Fig. 2 shows a schematic cross-sectional view of co-extrudate 22 in a forming wheel 28 including blades 27a and 27b. The cross-sectional profile shows how blade 27b shapes the outer dimension of the decorative trim strip product. Blade 27a provides a cut-line 33a (see Fig. 7) in the skin 56 of the co-extrudate 22 to define the outer dimension of a cut-out portion/window to expose the decorative film 54 below skin 56. The cut-out portion 33b remains in place and is removed later on by lifting an edge of this section and peeling it off as per the provided cut-line 33a after the decorative trim strip product was allowed to cool. After this portion 33b of the skin 56 is removed, the decorative film can be viewed through a cut-out window from a show surface to provide a decorative effect to the produced decorative trim strip products.

Fig. 3 shows a schematic cross-sectional view of a decorative trim strip product 32 according to the invention. The decorative trim strip 32 is shown supported on foil carrier 24 with the cut-out portion 33b of skin 56 removed to expose the decorative film 54. Edges 55a and 55b of decorative film 54 are enclosed by skin 56 so as to more firmly hold the decorative film 54 of decorative trim strip 32. The base 52 can be made from a thermoplastic material, such as polyvinyl chloride or a thermoplastic olefin. If desired, additional filler material/s is/are added to the base material so as to provide a relatively rigid support for the decorative trim strip 32.

Fig. 4 is a schematic top plan view of the decorative trim strip 32 according to the invention showing the cut-out window 58 of skin 56 to expose decorative film 54 to a show surface of decorative trim strip 32.

Fig. 5 is a schematic bottom plan view of the decorative trim strip 32 according to the invention showing the base material 52.

Fig. 6 illustrates a method of forming an extruded decorative trim strip according to the invention which is formed on a foil carrier 24 which moves consistently at a speed to minimize stresses on the softened plastic material. The decorative trim product in accordance with the invention includes a decorative film 54 embedded in the trim strip 32 between a base 52 and a skin 56 which are co-extruded as the decorative film 54 is provided. The thermoplastic materials for the base and the skin, and the decorative film, are merged together in a cross-head adaptor (not shown) and are then co-extruded from an extrusion die 20. Extrusion die 20 may have a profile designed for a predetermined or chosen profile of the decorative trim strip 32. If desired, the co-extrudate 22 has a predetermined cross-sectional shape which is of the same general shape as the desired final cross-section of the finished decorative trim strip 32. However, as will subsequently become apparent, the actual shape of the co-extruded strip can vary substantially from the final shape, but advantageously, has approximately the same cross-sectional area as the cross-sectional area of the finished decorative trim strip 32.

Co-extrudate 22 emerges from extrusion nozzle, 21 of die 20 under pressure from within the die 20. The extrusion nozzle 21 may have a shape to produce a decorative trim strip having a desired profile. Alternatively, co-extrudate 22 emerges from a same extruder. A foil carrier 24 unrolls from roll 25 and passes through the extrusion die 20 to emerge with the co-extrudate 22 and to pass, together with the co- extrudate 22 between a supporting idler wheel 26 and molding cavity 30 of a forming wheel 28. The foil carrier 24 can be made of aluminum foil, stainless steel, plastic foil, or any other suitable foil carrier.

Optionally, a roll 25' is positioned to feed the foil carrier 24 immediately after the extrusion process. The co-extrudate 22 is fed directly onto the foil carrier 24.

The surface of foil carrier 24 which receives the co-extrudate 22 has a low strength adhesive applied thereto. Low strength adhesive means an adhesive which will not permanently bond the co-extrudate 22 to the foil carrier 24, nor leave a residue on the formed decorative trim strips 32 after removal of the foil carrier 24. The foil carrier 24 can be peeled off of the decorative trim strip 32. Properties of a suitable adhesive are governed by time, pressure and temperature of the application of the adhesive to the co-extrudate 22.

As can be seen in more detail from Fig. 7, the forming wheel 28 has a molding cavity 30 including two blades 27a and 27b. As is apparent, the shape of extrusion nozzle 21 may not be of major importance since it is possible to mold the whole decorative trim strip in the cavity 30. A more detailed view of the molding cavity 30 of forming wheel 28 can be seen from Fig. 8 showing a more detailed view of a section of the forming wheel 28 of Fig. 7.

As the co-extrudate 22 and foil carrier 24 emerge from the extrusion die 20, the co-extrudate 22 lies above and is carried by the foil carrier 24. The foil carrier 24 passes around the periphery of idler wheel 26 carrying the co-extrudate 22 radially outwards of it so that co-extrudate 22 is sandwiched between the foil carrier 24 lying against the periphery of idler wheel 26 and molding cavity 30 of forming wheel 28. Cavity 30 is a profiled cavity 30 around the perimeter of forming wheel 28. The forming wheel 28 includes two blades, one for defining a circumference or periphery of the decorative trim strip 32 and another one for cutting out a portion/window so that the decorative film 54 is exposed to a show surface of the decorative trim strip 32. The cavity 30 forms a decorative trim strip 32 of the desired profile wherein blade 27b is used to shape the outer dimension of the decorative trim strip product and blade 27a is used to create a cut-line 33a in the skin 56 of the co-extrudate 22. The cut-line 33a defines the outer dimension of the cut-out section 33b to expose the decorative film 54 below the skin. The cavity 30 has a length greater than the

eventual length of cooled decorative trim strip 32 by an amount calculated to allow for shrinkage. This amount is relatively easy to determine by measurement in a stable process.

The foil carrier 24 is driven to travel at the speed at which the co-extrudate 22 is forced out of the extrusion die 20 and continues throughout its length at the same speed thereby minimizing or eliminating downstream stresses on the softened co- extrudate 22 as it is processed by downstream equipment such as forming wheel 28.

Foil carrier 24 carrying decorative trim strips 32 which are still soft emerge from the channel of forming wheel 28 and pass through a cooling tank 34. Various rollers 36 define the path of a conveyor system for moving foil carrier 24.

The foil carrier 24 still carrying trim strips 32 emerges from cooling tank or chamber 34. After the trim strips 32 are allowed to cool to room temperature the cutout portion 33b is removed along the cut-line 33a to expose the decorative film to a show surface of the decorative trim strip 32. It is apparent, that the side of the decorative film 54 bordering the skin 56 and more particularly the cut-out portion 33b does not stick to the cut-out portion 33b so that the cut-out portion 33b can be removed with ease.

Furthermore, foil carrier 24 is also removed after cooling to room temperature. The under surface of the decorative trim strip 32 on which the foil carrier 24 was adhered, is flat and smooth. Since the decorative trim strip 32 was cooled prior to removal, the ends of the decorative trim strip 32 remain in a flat condition. If desired, and as is well known in the art, an adhesive or double sided tape is applied to the underside of the decorative trim strip 32 for permanent attachment to the vehicle.

Furthermore, as can be seen from Fig. 6, speed sensors 42 may be provided at the nozzle of the extrusion die 20. Signals from the speed sensors may be fed to computer 44 which provides control signals to control the speed of the forming wheel 28.

The above described embodiments of the invention are intended to be examples of the present invention and numerous modifications, variations, and adaptations may be made to the particular embodiments of the invention without departing from the spirit and scope of the invention, which is defined in the claims.