MXPA99007059A - Process for making decorative automotive interior trim articles with integral light stable polyurethane elastomer covering - Google Patents

Abstract

A process for making a panel-like structure constructed to be mounted in an automobile vehicle to form a part of the interior thereof. According to this process, an outer layer (26) defining at least a portion of the exposed exterior surface of the structure is prepared by applying a water-dispersed thermoplastic polyurethane composition and a heat-activated reactive cross-linking monomer onto a mold surface and thereafter drying the composition. Next, a rapidly reacting composition is sprayed onto an inner surface of the outer layer while the outer layer is retained on the mold surface to form a polyurethane elastomer inner layer (28) that is interfacially chemically bonded to the outer layer. The inner layer with the outer layer interfacially chemically bonded thereto is then united with the rigid substrate (22) so that the rigid substrate serves to reinforce the outer layer. The exposed exterior surface of the panel-like structure simulates the appearance and feel of authentic leather, while the inner layer and an optional semi-rigid polyurethane cellular foam intermediate layer (44) provide a compressing feel to the exposed portion of the outer layer.

Description

PROCESS FOR THE MANUFACTURE OF ARTICLES OF INTERIOR FINISHING FOR AUTOMOBILES, WITH COVERING BASED ON THE ELASTOMER OF STABLE POLYURETHANE, IN LIGHT, INTEGRAL.

BACKGROUND OF THE INVENTION. Field of the invention.

The present invention describes a process for the manufacture of automotive interior trim articles containing a panel-like structure, constructed to be mounted on a motor vehicle to form a part of the inside thereof, and in particular for the production of articles automotive interior trim such as instrument panels, door panels, and glove box doors.

ANTECEDENTS OF THE TECHNIQUE Automotive interior trim items such as instrument panels, door panels, arm rests, head supports, floor consoles, knee braces, and glove compartments have been conveniently constructed by applying a Ref. soft decorative cover on a rigid substrate mounted on an automotive vehicle body, with a cellular polyurethane filler interposed between the decorative cover and the rigid substrate. Usually predetermined color and texture are provided to the decorative cover in an effort to simulate the appearance and texture of the authentic skin.

The preparation of a self-supporting, synthetic automotive interior finishing article having a double-layer covering is described in international application WO 93/23237 of Recticel, and in particular in example 2 thereof. In accordance with the method described in WO 93/23237 for the preparation of this interior finishing article, a solvent-dispersed polyurethane lacquer is initially applied to an open mold surface as a "paint in mold", and then it is dried by evaporating the solvent. A "skin" prepared from an elastomer of the two-part polyurethane type is subsequently formed on the surface of the mold-dried paint by the use of nozzles and special application systems. In practice, systems and spray nozzles that can be employed are described in US Pat. Nos. 5,028,006 and 5,071,683. Then, a layer of polyurethane-based cellular foam is prepared by spraying a polyurethane reaction mixture against the skin of the polyurethane elastomer. Finally, a polyisocyanurate or polyurethane reaction mixture is applied against the opposite surface of the polyurethane foam layer to obtain a synthetic carrier that is rigid.

The commercial merit of this prior dual layer cover technique containing the in-mold paint is described in WO 93/23237, and the process for the manufacture thereof is negligible, as the current commercial activity of Recticel makes evident, the owners of WO 93/23237. Recticel does not use a solvent-based lacquer in its commercial activity. Recticel has even banned its customers from using their paint in mold.

In addition, the provision of solvent-based lacquer as an in-mold paint makes the preparatory method described in WO 93/23237 untimely with various complications and inefficiencies. For example, these lacquers contain large amounts of volatile organic compounds (VOCs). Due to the extremely flammable and explosive nature of VOCs, such lacquers are subject to strict government regulations. In accordance with these government regulations, it is often necessary to design additional and expensive equipment to ensure safety and to protect the worker from environmental pollution. For example, equipment to facilitate the manufacture and handling of such lacquers should include special spray equipment, well-spaced and separated spray zones, and air cleaning equipment. In addition, the worker must wear often cumbersome and bulky items for special protection that are fire resistant and protect him from exposure to noxious fumes.

Accordingly, there is a need to provide a process for the manufacture of a panel-like structure containing a multi-layer decorative cover in which the panel-like structure can be produced in a more cost-effective and efficient manner, and in which the resulting panel-like structure has a high-quality leather appearance.

BRIEF DESCRIPTION OF THE INVENTION Until then, it is an object of the present invention to solve the aforementioned problems associated with the prior art as well as the needs expressed above. In accordance with the principles of the present invention, this object is to obtain and provide a process for the manufacture of a panel-like structure, adaptable to an automotive vehicle so that it forms a part of the interior thereof. The panel-like structure includes an outer layer defining an exterior surface of the structure, at least a portion of such an outer layer is exposed to the interior of the vehicle, and a rigid substrate defining an interior surface of the structure. The substrate is concealed from inside the vehicle when the panel structure is mounted inside the vehicle.

In accordance with one modality of this process, at the same time the following steps are carried out for the preparation of a structure as a panel. First, a composition dispersed in water comprising at least one stable, light, aliphatic, thermoplastic polyurethane containing one or more pendant carboxyl and / or hydroxyl functional groups, a desired coloring agent, and a crosslinked, heat-activated reaction monomer is applied on a hot molding surface formed to define a configuration corresponding to the outer layer. The crosslinked monomer of the heat activated reaction is preferably carbodiimide. The slightly stable thermoplastic polyurethane and the crosslinked heat activated reaction monomer are heated, preferably by preheating the molding surface, and causing the reaction for the attachment of the thermoplastic polyurethane to the reactive crosslinked monomer. Second, the composition dispersed in water is substantially dried while on the molding surface to form the exposed outer layer with an outer surface, at least a part of which has the desired feel, color, and configuration of the structure in a manner of panel. Third, a fast reaction composition containing at least one polyisocyanate and at least one polyol is sprayed onto an inner surface of the outer layer while on the molding surface an inner layer is formed which comprises a cross-linked polyurethane type elastomer. with the polyurethane of the outer layer via non-reactive functional groups of the reactive crosslinked monomer in the outer layer. Accordingly, a composite layer structure having interfacial chemical bond between the inner surface of the outer layer and an adjacent surface of the inner layer is obtained. Four, the inner layer with the outer layer chemically bonded interfacially thereof, ie, the layer structure of the composite, is bonded with the rigid substrate so that the rigid substrate serves to reinforce the outer layer. Optionally, a foamed layer of soft cellular polyurethane intermediate the inner layer and the rigid substrate can be formed. Consequently, the panel-like structure retains the touch and color of the exposed part, which can simulate the appearance and texture of the real skin and the sensation of compression provided to the outer layer by the inner layer and the foamy intermediate layer. soft optional.

The composite layer structure produced in accordance with this embodiment shows excellent chemical resistance, scratches and deterioration of external influences. In addition, suitable additives may be introduced into the composition to provide the composition with the appearance of a low-gloss, non-reflective surface desired for such panel-like structures. further, both inner and outer layers of the composition are characterized by being excellently extensible, so that the composition can resist dents and bending during use without causing breakage in the outer layer over a wide range of temperature, such as from -30 ° C to 80 ° C.

The principles of the present invention set forth above are applicable to the production of all types of panel-like structures, but have a particular applicability in instrument panels, (also known as instrument panels) and door panels. On the other hand, the principles of the present invention are applicable for the production of panel structures for various types of vehicles, including passenger buses, trucks, vans, work vehicles and others.

These and other objects, embodiments, and advantages of the present invention will appear from the following detailed description when considered in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings illustrate the present invention. In such drawings: Figure 1 is a perspective view and partially sectioned and partially broken lines of a finished vehicle door panel constructed by the process of the present invention; Figure 2 is a perspective view of a vehicle instrument panel constructed by the process of the present invention; - ¬ Figure 3 is a sectional view of the instrument panel of Figure 2 taken along the line III-III; Figure 4 is a sectional view of a mold or molding surface showing a step of applying a polyurethane composition dispersed in water to the molding surface while heating to form an outer layer of stable polyurethane, to light, crosslinked in accordance with the present invention; Figure 5 is a sectional view similar to Figure 4 and shows a drying step of the outer layer of polyurethane; Figure 6 is a sectional view similar to Figure 5, and shows a step to obtain an inner layer by spraying a quick reaction composition on an inner surface of the outer layer while the outer layer is retained on the surface of molding; - - Figure 7 is a sectional view similar to Figure 6 and shows a step for removing the combination of the inner and outer layers from the molding surface; Fig. 8 is a sectional view of a second molding surface showing a step to obtain a relatively rigid polyurethane foamed intermediate cellular layer by applying a reaction mixture to the inner layer while the combination of the inner layers and external is disposed on a second molding surface in accordance with an embodiment of the method of the present invention; and Figure 9 is a sectional view showing a step for joining the combination of the inner and outer layers on the second surface with a relatively rigid substrate disposed on a third molding surface.

DESCRIPTION OF THE PREFERRED MODALITIES Referring now more particularly to the drawings, there is shown in Figure 1, a panel-like structure comprising a vehicle door panel, generally designated by the reference numeral 10, constructed by one embodiment of the method in accordance with the principles of the present invention. A door panel 10 includes a window top portion 12 and a arm rest portion 14 defining therebetween a cross member receiving portion 16. A portion 18 receiving the lower flat mat having a mat section 20 connected thereto is disposed below the arm rest portion 14. As shown in the cross section of Fig. 1, the panel-like structure 10 it has an exterior surface 10a exposed to the interior of the vehicle and an interior surface 10b which is concealed from the interior of the vehicle when the panel-like structure 10 is mounted on the motor vehicle. The panel-like structure includes a rigid substrate 22 having a surface defining the interior surface 10b of the structure 10 in the manner of a panel. The panel-like structure 10 further comprises a layer composition structure, generally designated by the reference numeral 24, and comprising an outer layer 26 defining at least a portion of the exposed outer surface 10a of the panel-like structure 10 and an inner layer 28. At least a portion of the outer layer 26 is exposed to the interior of the vehicle, while a part of the outer layer can be hidden from view by the concealed or decorative item. For example, in Figure 1, the part 18 receiving the lower plane mat of the outer layer 26 is covered by the mat section 20 and, consequently, is not exposed to the interior of the vehicle.

As shown in figure 1, the inner layer 28, which is relatively thick compared to the outer layer 26, has an adjacent external surface 28a chemically bonded interfacially with an inner surface 26b of the outer layer 26. As further shown in Figure 1, the rigid substrate 22, which is hidden from inside the vehicle when the structure 10 is mounted as a panel in the motor vehicle, and reinforces the inner and outer layers 26 and 28. Finally, an intermediate layer 30 that contains a foamy cellular filler of relatively rigid (or semi-rigid) polyurethane is interposed between the inner layer 28 and the rigid substrate 22.

- - As shown in Figure 4, the method of the present invention for the manufacture of the aforementioned articles uses a first molding component or part 32 having a first molding surface 34. The first molding component 32 is preferably formulated by the deposit of nickel electrolytically on a molten and rigid epoxy substrate which is secondarily removed at the end of the deposition / nickel process to produce a self-supporting mold capable of being assembled and controlled in a mounting module. The first molding surface 34 is formed to define a configuration that substantially corresponds to the desired configuration of the outer layer 26, and is granulated to define a texture that substantially complements the desired texture of the outer layer 26 and simulates the authentic skin.

Figure 4 illustrates the third step in the present invention and, in accordance with this step, the outer layer 26 is obtained by the application, preferably by spraying, of a composition 36 dispersed in water on the first molding surface 34. The composition dispersed in water comprises at least one thermoplastic polyurethane, aliphatic, stable, light containing one or more pendant carboxyl and / or hydroxyl functional groups, at least one desired coloring agent, and at least one crosslinked activated reaction monomer by heat. Carbodiimide (H-N = C = N-H), also known as cyanamide, preferably serves as the crosslinked monomer of the heat activated reaction. Other appropriate crosslinked monomers, such as aziridine, can be used.

The application of the composition 36 dispersed in water on the first heated molding surface 34, induces the chemical reaction between one or more of the pendant carboxyl and / or hydroxyl functional groups of the stable, light-stable thermoplastic polyurethane and the crosslinked monomer of heat-activated reaction so that in this way a stable, light-curing, cross-linked polyurethane is produced. The first molding surface 34 should be heated to a temperature sufficient to generate the crosslinking reaction, but should not be so high that the composition 36 is divided into sheets from the molding surface 34. Preferably, the first molding surface 34 is heated to a temperature in - - the range from about 140 ° F (60 ° C) to about 160 ° C (71.1 ° C). Heating the first molding surface 34 to such high temperatures prior to the application of the composition 36 dispersed in water thereto further serves to melt and disperse the molding release agents, such as microcrystalline wax molding release agents, applied to the first molding surface 34. Thus, the molding release agent is prevented from collecting on the intricate details of the first molding surface 34.

The composition 36 dispersed in water can be prepared by separating the stable aliphatic thermoplastic polyurethane to light and the crosslinked monomer of heat-activated reaction from separate storage chambers in continuous, measured streams, and mixing these constituents immediately. before contact with the first molding surface 34. Alternatively, the thermoplastic aliphatic polyurethane, stable, light and the constituents of the carbodiimide can be previously mixed stably, or "cook in a pot" for more than about 24 hours at room temperature before application. This technique is known as "pot cooking" since the thermoplastic polyurethane and the carbodiimide react slowly between them at room temperature in a pressure cooker, if the mixture is heated in a pot for more than 24 hours at room temperature, before its application on the first molding surface 34, the stable polyurethane, to the crosslinked light exposes a lower solvent and shows properties of strength and extensibility.

Once the stable polyurethane has been formed, in the light crosslinked on the first molding surface 34, the composition 36 dispersed in water now contains the stable polyurethane, in the crosslinked light it is substantially dried since it is retained on the first molding surface 34 to obtain the outer layer 26. As shown in Figure 5, the light, stable, crosslinked polyurethane can be fastened to a heat source 40 to induce evaporation to the water and the solvent thereof and form the layer external 26 with an outer surface 26a adjacent to the first molding surface 34. Although not shown in Figure 5, such a heat source 40 is preferably integrated with the first molding surface 32, and preferably heats the first molding surface 34 at an elevated temperature of about 150 ° F (65.9 ° C) or higher. At least a portion of the outer surface 26a of the outer layer 26 has the texture, color and configuration as desired granules of the panel-like structure 10. Generally, the outer layer 26 has a thickness within the range of about from the 1.0 mil to about 1.5 mil (which is around 0.001 inches to about 0.0015 inches, or from around 0.0025 inches to about 0.0038 inches).

The particular coloring agent selected can directly influence the desired thickness of the outer layer 26. Darker colors, such as gray and green, usually only require a thin film to conceal the color of the hidden inner layer 28 , considering that lighter colors such as reds and yellows usually demand the provision of a relatively thicker layer for obtaining non-transparent and opaque outer layer 26 that conceals the inner layer 28 of the view.

Then, the inner layer 28 of the polyurethane elastomer, as shown in Figure 6, is formed by spraying the quick reaction composition 42 on the inner surface 26b of the outer layer 26 while the outer layer 26 is retained on the outer layer 26b. first molding surface 34 in a substantially anhydrous state. The quick reaction composition 42 contains at least one polyisocyanate and at least one polyol, which react with each other to form the inner layer 28 of the polyurethane elastomer. As referred to herein, the term "elastomer" encompasses any elastic flexible polymer composition under moderate tension and having a relatively high tensile force and tendency to regain its shape so that, upon release from tension, the elastomer is retracted within and recover their original dimensions or dimensions substantially similar to their original dimensions.

- - Further, to achieve the reaction with the polyisocyanate constituent, the polyol constituent of the quick reaction composition 42 may contain one or more carboxyl and / or hydroxyl functional groups which are highly reactive with the unreacted carbodiimide functional groups in the layer external 26 which has not reacted with the pending functional groups of the polyurethane of the outer layer 26. The unreacted functional groups of the carbodiimide penetrate inside the inner layer 28 and react with the pending functional groups of the polyol constituent. As a result, crosslinking of the carbodiimide with the polyurethane of the outer layer 26 is effected with the polyurethane elastomer of the inner layer 28 and therefore an interfacial chemical bond is formed between the inner surface 26b of the outer layer 26 and the surface adjacent external 28a of the inner layer 28. Thus in this way, the layer composition structure 24 is obtained. If the crosslinking is carried out under optimum crosslinking conditions, the boundary between the outer and inner layers 26 and 28 of the structure 24 of layer composition becomes visually indistinct, so that a transition phase appears at the interface of the two layers. As expressed herein, encompassing the interfacial chemical bond is not limited to those crosslinked reactions in which the interfacial boundary between the inner and outer layers 26 and 28 is visually indistinct and inseparable.

Generally, provisions must be made to ensure that a suitable interfacial chemical bond is made between the inner surface 26b of the outer layer 26 and the adjacent external external surface 28a of the inner layer 28. For example, once the carbodiimide is activated by heat, the crosslinking reaction between the carbodiimide and the reactive carboxyl and / or hydroxyl reactive groups of the thermoplastic polyurethane will complete within minutes, which substantially leave no residual sites in the carbodiimide to crosslink the polyurethane of the outer layer 26 with the polyol constituent of the rapid reaction composition 42. Until then, the rapid reaction composition 42 should generally be sprayed within six minutes, and preferably within two to four minutes, to conclude the application of the composition 36 dispersed in water to the first molding surface. Significant delays in spraying the quick reaction composition 42 can also cause the outer layer 26 to shrink and divide into sheets from the first molding surface 34. As a consequence of the division into sheets, the outer layer 26 it will not have a shape corresponding to the configuration of the first molding surface 34, and the complete composition 24 will not have the disposition as waste.

On the other hand, if the thermoplastic polyurethane of the composition 36 dispersed in water does not give sufficient time for the crosslinking before the quick reaction composition 42 is sprayed thereon, the polyol component of the quick reaction composition 42 can be subjecting a condensation reaction with the unreacted carboxyl and / or unreacted hydroxyl functional groups of the polyurethane of the outer layer 26 to form an ester or ester linkages, respectively. While some formation of these bonds can advantageously increase the interfacial chemical bond, the condensation reactions release water, which in excess amounts can act as a blowing agent and undesirably increase the porosity of the inner layer. and interferes with the interfacial chemical bond.

The interfacial chemical bond is additionally increased by separate storage of the highly reactive polyol and the constituent components of the quick reaction composition 42 in separate storage chambers and spraying these components on the inner surface 26b of the outer layer 26 in order to avoid the contact between these components until the spray is applied. A suitable dual spray mechanism for performing this task is described in U.S. Patent Nos. 5,028,006 and 5,071,683. To keep these components separated until immediately before spraying, a portion of the polyol reacts with the carbodiimide (and the carboxyl and / or hydroxyl pendant functional groups of the thermoplastic polyurethane) before all of the polyol can fully react with the polyisocyanate.

In addition, given the hygroscopic nature of the polyisocyanate constituent of the quick reaction composition 42, it is important that the outer layer 26 and the redundant atmosphere (eg, moisture levels) be substantially anhydrous during this spraying step so as to to obtain a strong interfacial chemical bond. While small amounts of moisture can be retained in outer layer 26, the concentration of such moisture should not be so great that it allows water to substantially interfere with the reaction between the polyol and the polyisocyanate constituents of the quick reaction composition 42 . Undesired reactions between the water and the polyisocyanate can break the stoichiometric balance between the polyol and the polyisocyanate, leaving unreacted polyol deposits located behind on the layer composition structure 24. The water can also serve as a blowing agent, reacting with the polyisocyanate to liberate carbon dioxide which imparts a cellular structure to the inner layer 28. Excessive amounts of water can also interfere causing deterioration in the crosslinking reaction effected via the polyol and residual reactive sites of the carbodiimide reactive crosslinked monomer.

The rapid reaction composition 42 is preferably applied to the inner surface 26a of the outer layer 26 at an elevated temperature to advance these objectives. Appropriate temperatures at which the first molding component 32 can be heated within the range, by way of example and without limitation, from about 140 ° F (60 ° C) to about 160 ° F (71.1 ° C) ).

Generally, the inner layer 28 can have a thickness in the range from about 40 mils to about 60 mils (ie, from about 0.040 inches to about 0.060 inches, or from about 0.10 inches. up to around 0.15 cm).

Figure 7 illustrates the next step of the present invention. As shown in Fig. 7, the layer composition structure 24 is demoulded (ie, removed) from the first molding surface 34. The demolding process is often an intense, tedious task, and a task that it consumes time The formation of unduly stretched or undone tears of the layer composition structure 24 during demolding can irreversibly ruin, and thus create the need for the removal of the layer composition structure 24 as waste. Such problems and inefficiency in the demolding are overcome by the practice of the present invention, since the interfacial chemical bond between the outer layer 26 and the inner layer 28 reinforces the structure 24 of layer composition avoiding the separation of the inner and outer layers. 26 and 28 during the demolding process.

To increase the separation property of the first molding surface 34 further, the molding surface 34 can be pretreated with a release agent. Exemplified release agents include, without limitation, molding release agents of high molecular weight microcrystalline wax, such as Chem-Trend PRC 7140, supplied by Chem-Trend, Inc. of Howell, Michigan, or PRC 2006, also supplied by Chem-Trend. These molding-release agents dry quickly on a hot mold within 5 to about 10 seconds and form a releasing barrier - between the granulated molding surface 34 and the outer layer 26. Care must be taken to avoid accumulation of the release agent. release of molding on the first molding surface 34 or an excess in solid contents in the agent, since such an accumulation of excess solid contents tend to fill the slits of the granulated molding surface 34, whereby it is removed from the surface exterior of the structure 10 as a panel the appearance of the hair-like granular configuration of the molding surface 34. In addition, the use of excess molding releasing agents can cause the agent to be transferred from the first molding surface 34 to the structure 24 of layer composition during the demolding of the composition of structure 24, requiring Separation with water additionally and the drying steps after demoulding and consequently a loss in productivity.

After demolding the first molding surface 34, the layer composition structure 24, which includes the combination of the inner and outer layers 26 and 28, the defects can be examined by a light source (not shown) while the Structure 24 of layer composition is placed on a transparent substrate (not shown). Such defects are usually presented as cosmetic imperfections in the outer layer 26, and may include the presence of tearing and tearing portions that lack sufficient thickness to withstand the stretch associated with demolding or the additional processing steps, especially the joining steps . If they are small and isolated, such localized defects can be remedied by the subsequent application of the composition 36 dispersed in additional water on the outer layer 26. Additionally, minor ruptures, or thin areas can be repaired using a thermoplastic, heat-formable polyurethane tape on the back 28b of the layering structure 24. Advantageously, the need to discard the complete layer composition structure 24 is therefore prted. As a warning note, how, the subsequent application of repair spray to the surface 26a is generally undesirable and its use in correcting localized defects must be minimized, since subsequent application of repair spray can nullify the appearance similar to the granulated skin of the outer surface 26a of the outer layer 26 which is transcribed from the first molding surface 34.

As discussed in more detail below, the step of demolding and examination of the layer composition structure 24 of the first molding surface 34 is not required to be subsequently conducted immediately for the formation of the layer composition structure 24. For example, the layer composition structure 24 can optionally be maintained against the first molding surface 34 until the completion of the structure 10 as a panel.

After the layer composition structure 24 is demoulded from the first molding surface 34 and examined, the layer composition structure 24 is placed on a molding surface 52 of a second molding portion 50. As shown in FIG. 8, the second molding surface 52 is also formed to define a configuration corresponding to the outer layer 26. Then, a reaction mixture 44 for forming a semi-rigid cellular foam, such as a semi-rigid polyurethane foam, is applied to a internal surface 28b of the inner layer 28 while the composition structure 24 is disposed on the second molding surface 52 to form the intermediate layer 30. The reaction mixture 44 can be applied, for example, by the use of a mixture of high shock and a mixing head nozzle. The second molding component 50 is generally heated to a temperature in the range of from about 40 ° C to about 60 ° C, and more preferably in the range from about 40 ° C to about 50 ° C. , during the application of the reaction mixture. The mixture 44, which is relatively viscous typically, is in a transient reaction state during its application to the second molding component 50 and starts foaming in seconds after the application.

Although the desired thickness of the intermediate layer partially depends on the purposes of use of the panel-like structure 10, generally the intermediate layer has a thickness in the range from about 5 mm to about 12 mm.

Once the reaction mixture 44 has been applied to the layer composition structure 24 located on the second molding surface 52, a third or cooperating molding component 60 which carries the previously formed rigid substrate 22 moves within a cooperating relationship with the second molding component 50, as shown in Fig. 9. The third molding component 60 has a third molding surface 62 (Fig. 8), which is formed to define the inner surface 10b of the structure 10 as a panel. Subsequently, the reaction mixture 44 is foamed and cured, preferably under a heat of about 110 ° F (43.3 ° C), a self-generated cavity pressure of about 0.8 at. to form the intermediate layer 30. The semi-rigid polyurethane foam is used to join the layering structure 24 with a pre-formed rigid substrate 22 arranged on a third molding surface 62. The panel-like structure includes the combination of the layer composition structure 24, the rigid substrate 22, and the intermediate layer 30 can then be removed from the molding parts 50 and 60 and additional components, such as the carpet section 20, can be fixed.

In its broader aspects, many variations and modifications to the process discussed above may be implemented without departing from the scope of the present invention. For example, the layer composition structure 24 and / or the intermediate layer 30 can be removed from the receiving part 18 of the hidden bottom flat mat (or other part that is hidden from the interior of the vehicle when the structure is referred to as a panel). in the motor vehicle) of the panel structure 10 resulting in Figure 1, so that the receiving part 18 of the flat mat is characterized in that it has a rigid substrate 22 directly adjacent to the carpet section 20.

In accordance with another variant embodiment of the present invention, a non-foaming adhesive can be selected to bond the layering structure 24 with the rigid substrate 22.

According to yet another variant embodiment of the present invention, multiple compositions dispersed in water containing different coloring agents can respectively be applied to different parts of the panel-like structure to produce discrete cloaking colors. Where the selected color or colors are changed, in practice it has been found that minimum unproductive time is required (in the order of 1.5 hours).

In accordance with yet another variant embodiment of the present invention, the outer layer 26 may exhibit multiple tone or dual tone appearance. This variant of the embodiment can be realized, for example, by means of an abrasive treatment of a part of the molding surface of the tooling. The greater the amount of abrasive treatment, the greater the lack of gloss of the appearance of the outer layer 26. A dual tone appearance can be especially desired, since the upper region of an instrument panel must have a low gloss in order to reduce Reflection and minimize intense and annoying light.

Still other variations of the process can be implemented, such as the retention of the layer composition structure 24 in the first molding component 32 instead of the demolding and transfer of the structure 24 to a second molding component 50 for the joining step. . In accordance with another variant embodiment of the present invention, the layering structure 24 can be returned to the first molding component 32 after being examined and treated.

According to yet another variant of the present invention, a secondary or alternative heat source can be applied for the activation of the reaction between the light-stable, aliphatic, thermoplastic polyurethane and the crosslinked, heat-activated reaction monomer. For example, the composition 36 dispersed in water can be preheated prior to its application to the first molding surface 34, so that the first molding surface 34 does not have to be heated to initiate the reaction between the crosslinked reaction monomer activated by heat and the aliphatic thermoplastic polyurethane stable to light.

- - According to yet another variant of the embodiment of the present invention, the reaction mixture 44 for the formation of the semi-rigid polyurethane cellular foam 30 can be applied to the surface of the rigid substrate 22 instead of the layer composition structure 24. . Alternatively, the second and third molding components 50 and 60 can be co-operatively enpotrated to define a cavity between the inner surface 28b of the inner layer 28 and the outer surface of the substrate 22, with the reaction mixture 44 after this is injected between the rigid substrate 22 and the composition 24.

In order to additionally claim the method of the present invention, the following discussion specifies the preferred and appropriate constituents and conditions for the manufacture of the article of the present invention and for carrying out the process of the present invention.

The composition 36 dispersed in water used to prepare the outer layer 26 comprises at least one thermoplastic polyurethane, aliphatic, light stable at least one desired coloring agent, and at least one reactive crosslinked monomer. The light-stable aliphatic thermoplastic polyurethane is preferably prepared from a thermoplastic, aliphatic, high molecular weight polyurethane containing carboxyl and / or hydroxyl pendant functional groups which are chemically reactive with the carbodiimide. The average high molecular weight thermoplastic polyurethane is preferably in the range from about 5000 to about 7000 and more preferably up to about 6000. An exemplary thermoplastic polyurethane and carbodiimide can be obtained from C.F. Jameson &; Company, Inc. of Bradford, Mass. Under the designation treaty JAMESON WVF SERIES FLEXCOAT IMC. the desired weight of the radius of the aliphatic thermoplastic polyurethane to the carbodiimide for this particular composition is about 8 to 1 by volume (radius equivalent of 1.44 thermoplastic polyurethane at 1.08 carbodiimide on a dry basis).The composition 36 dispersed in water can be prepared by means of providing the thermoplastic polyurethane component as a colloidal solution in a solvent such as N-methyl pyrrolidone, then dispersing the solution by adding water, the coloring agent and the conventional additives, if desired Sufficient water can be added so that the concentration of the solvent in composition 36 dispersed in water is about 13.9% by weight, and about 35% by weight after drying.

Optional additives in composition 36 dispersed in water 36 may include, without limitation, any combination of the following: ultra violet and heat light stabilizers, pH stabilizers to maintain an alkaline state of the dispersion, plasticizers, antioxidants, tarnish agents , surfactants, colloidal protectors to keep the particles in suspension, carbon black, thixotropic agents (hydroxy methyl cellulose), and fillers such as clay particles.

The composition 36 dispersed in water may contain, for example, about 20% to about 30% solids by weight, and more preferably about 24% by weight, about 10% to about 80% water by weight, and more preferably about 50% water by weight, and about 9 to 15% solvents by weight, depending on the color and additives desired. An insufficient amount of water in the composition 36 may adversely affect the viscosity of the composition 36 and thus adversely affect the application of the composition 36 dispersed in water on the molding surface 34. On the other hand, an excessive amount of water in the composition 36 can significantly alter the spraying and coating efficiency of the dispersed composition in water 36.

A solution of the carbodiimide is added to the thermoplastic polyurethane solution, which may include, for example, ether glycol acetate and / or xylene as the solvent. When combined and activated by heat, the crosslinked monomer preferably reacts with the carboxyl and / or hydroxyl groups of the thermoplastic polyurethane for the crosslinking of the thermoplastic polyurethane with the same or with the polyol constituent of the quick reaction composition 42. Exemplary polyisocyanates that can be selected for the quick reaction composition 42 - used to prepare the inner layer 28 include polyisocyanates having aliphatic ring structures with pendant NCO groups, such as isophorone diisocyanate, which can be obtained from low Recticel the ISOFAST trademark. Also suitable is tetramethyl xylene diisocyanate, which can be obtained from Texaco under the trademark TMXDI. Aromatic polyisocyanates not stable to light are more desirable than the currently available aliphatic polyisocyanates because of their lower costs, higher predictable reactivity, and higher breaking strength compared to the light-stable aliphatic polyisocyanates.

Appropriate polyols for this rapid reaction composition 42 include, without limitation, polyether polyethers having average molecular weights in the range from 220 to about 250 and containing one or more pendant carboxyl and / or hydroxyl groups (in addition to hydroxyl groups) primary ones), which can react chemically with the non-reactive NH functional groups of the carbodiimide and the carboxyl and / or hydroxyl pendant functional groups of the outer layer polyurethane 26. An exemplary polyol is POLIFAST by Recticel.

The quick reaction composition 42 may also contain appropriate additives, including, by way of example and without limitation, any combination of the following: ultraviolet and heat stabilizers, pH stabilizers, antioxidants, tarnish agents, surfactants, black of carbon, chain extenders (for example ethylene glycol), thixotropic agents, (for example amorphous silica), fillers such as clay particles, and catalysts such as tin catalysts (for example, dibutyltin dilaurate) tin).

Various blends of polyether polyols and polyisocyanates having appropriate resilience properties can be employed to form the semirigid polyurethane foam of intermediate layer 30. For example, the polyisocyanate mixture can include methylene diisocyanate. The semi-rigid polyurethane foam may also contain appropriate additives, including, by way of example and without limitation, any combination of the following: surfactants, antioxidants, fillers, stabilizers, catalysts, such as tin catalysts (eg, dilaurate) of dibutyl tin) and tertiary amines (eg, diethanolamine), and small amounts of foaming agents such as water. In this regard, it has been noted that the condensation reaction between the polyol and polyisocyanate mixtures release water, which reacts with the polyisocyanate to generate carbon dioxide and thereby impart the cellular structure to the intermediate layer 30. Accordingly, a slight stoichiometric excess of the polyol can be provided to form the semirigid polyurethane foam.

The rigid substrate 22 may be selected from any material having the requisite strength to reinforce and assemble the outer layer 26, the inner layer 28, and the intermediate layer 30. Suitable materials include any material with sufficient rigidity to allow the composition to be mounted within a vehicle substructure, which includes, by way of example, injection molded thermoplastics, such as, without limitation, maleic anhydride styrene (SMA), styrene butadiene acrylonitrile (ABS), polycarbonate (PC), an alloy of ABS-PC, molded reinforced reaction injection polyurethanes (RRIM), metals, metal alloys, wood fiber compositions, or any combination thereof.

Although the method of the present invention has been described in various embodiments previously in connection with the preparation of a door panel, it is understood that the method is equally applicable to other panel-like structures, including for example, instrument panels, rests arm, head support, floor consoles, knee braces, glove box doors. For example, the method of the present invention can be used to manufacture the instrument panel illustrated in perspective and the cross-sectional views in Figures 2 and 3, respectively, which are generally designated by the reference number. The instrument panel 100 is shown in the cross section of Figure 3, and includes a rigid substrate 122, an outer layer 126 and an inner layer 128 (collectively a layer composition structure, generally designated by reference number 124) , and an intermediate layer 130. The full descriptions of any US or foreign patent applications cited or mentioned hereinabove are here within the present application. It will be seen in this way that the objects and principles of the present invention have been fully and effectively realized. It will be noted, however, that the preferred specific embodiments have been shown for the purposes of this invention and are subject to change without departing from such principles, subsequently, this invention includes all variations, modifications, and improvements encompassed within the scope and spirit of the following appended claims. It is noted that in relation to this date, the best method known by the applicant, to bring the invention into practice, is that it is clear from the present description of the invention. Having described the invention as above, property is claimed as contained in the following:

Claims (17)

REVTNDICATIONS

1. A process for the manufacture of a panel-like structure constructed to be mounted on a motor vehicle to form part of the interior thereof, the panel-like structure includes an outer layer that defines an exterior surface of the structure, at least a part of which is exposed inside the vehicle, and a rigid substrate that defines an interior surface of the structure which is hidden inside the vehicle when the panel-like structure is mounted on the motor vehicle, said process is characterized in that it comprises the step from: the application of a composition dispersed in water comprising at least one light-stable aliphatic thermoplastic polyurethane containing at least one pendant functional group selected from the group consisting of carboxyl and hydroxyl functional groups, at least one desired coloring agent , and a crosslinked heat activated reaction monomer on a first forming surface formed to define a corresponding configuration of the outer layer; heating and therefore crosslinking the aliphatic thermoplastic polyurethane, stable to light with the crosslinked monomer of heat-activated reaction; substantially drying the composition dispersed in water while on the molding surface the outer exposed layer is formed with an outer surface, at least a part of which has the texture, color, and configuration of the structure similar to a panel desired spraying a quick reaction composition containing at least one polyisocyanate and at least one polyol on an internal surface of the outer layer while on the first forming surface an inner layer is formed which comprises a polyurethane type elastomer crosslinked with the polyurethane of the outer layer via the non-reactive functional groups of the crosslinked monomer of the heat-activated reaction and thereby forming a chemical interface bond between the inner surface and the outer layer and an adjacent surface of the inner layer; Y joining the inner layer with the outer layer chemically bonded interfacial to it with the rigid substrate so that the rigid substrate serves to reinforce the outer layer while maintaining the texture and color of the exposed part.

2. A process according to claim 1, characterized in that the crosslinked monomer of the reaction activated by heat is carbodiimide.

3. A process according to claim 2, characterized in that at least one polyol contains one or more hydroxyl, carboxyl or, hydroxyl and carboxyl functional groups, pending.

4. A process according to claim 3, characterized in that it additionally comprises the steps of: transferring the inner layer with the outer layer chemically interfacing it thereof from the first molding surface to a second molding surface; and providing the rigid substrate on a third molding surface that defines the interior surface of the structure as a panel, wherein said joining step comprises applying a reaction mixture to the inner layer with the external layer chemically bonded in an interfacial manner thereto while while on the second molding surface, the second and third molding surface are placed end of the inner layer with the outer layer bond chemically interfacial to it and the rigid substrate collectively define a mold cavity to accommodate the reactive mixture, foaming the reaction mixture to form a relatively rigid polyurethane foam cell, which adheres to the rigid substrate to the inner layer with the outer layer chemically bonded interfacially thereto, and wherein the outer layer is provided with a compressive feel by the relatively rigid polyurethane foam and the inner layer.

5. A process according to claim 4, characterized in that it comprises the additional steps of: transferring the inner layer with the external layer chemically bonded in an interfacial manner thereto from the second molding surface to a transparent surface of a clamping platform; detecting and reinforcing the parts susceptible to rupture of the inner layer with the outer layer chemically bonded interfacially thereto to prevent its failure during the joining step.

6. A process according to claim 3, characterized in that said drying step is carried out by means of the evaporation of the water of the composition dispersed in water.

7. A process according to claim 3, characterized in that the outer layer has a thickness within the range from about 1.0 mil to about 1.5 mil.

8. A process according to claim 3, characterized in that the inner layer has a thickness within the range from about 40 mils to about 60 mils.

9. A process according to claim 3, characterized in that it additionally comprises the step of previously coating the first molding surface with a molding release agent of microcrystalline wax.

10. A process according to claim 3, characterized in that at least one light-stable aliphatic thermoplastic polyurethane and the crosslinked heat activated reaction monomer can be premixed and stored prior to said application step for at least 24 hours at room temperature.

11. A process according to claim 3, characterized in that the first molding surface is heated during said spraying step.

12. A process according to claim 3, characterized in that the first molding surface is formed to define a corresponding configuration of an outer surface of a door panel.

13. A process according to claim 3, characterized in that the first molding surface is formed to define a configuration corresponding to an outer surface of an instrument panel.

14. A process for the manufacture of a panel-like structure constructed to be mounted on a motor vehicle, to form a part of the inside thereof, the panel-like structure includes an outer layer defining an exterior surface of the structure, less a part of which is exposed inside the vehicle, and a rigid substrate defining an interior surface of the structure which is hidden from the interior of the vehicle when the panel-like structure is mounted on the motor vehicle, said process is characterized comprises the steps of: pre-coating with a microcrystalline wax mold release agent on a first mold or molding surface, the first molding surface is heated to a first elevated temperature to melt and disperse the release agent. molding, microcrystalline wax; applying a composition dispersed in water comprising at least one light-stable, aliphatic, thermoplastic polyurethane containing at least one pendant functional group selected from the group consisting of carboxyl and hydroxyl functional groups, at least one desired coloring agent , and a cross-linked monomer of heat-activated reaction on the first molding surface containing the microthrystalline wax molding release agent dispersed thereon, the first molding surface is formed to define a configuration corresponding to the outer layer maintaining the first molding surface at a second elevated temperature during said application step of a composition dispersed in water and therefore the aliphatic thermoplastic polyurethane, stable to light with the crosslinked monomer of the heat activated reaction; substantially drying the dispersed composition in water while on the first molding surface by heating the first mold or molding surface a third elevated temperature the exposed outer layer is formed with an outer surface, at least a part of which has the desired panel color, texture, and structure configuration; spraying a quick reaction composition containing at least one polyisocyanate and at least one polyol on an internal surface of the outer layer while on the first forming surface heated to a high elevated temperature an inner layer is formed which comprises polyurethane elastomer cross-linked with the polyurethane of the outer layer via functional groups which do not react with the crosslinked monomer of the heat-activated reaction and therefore the formation of the chemical interface bond between the inner surface and an adjacent surface of the inner layer, and joining the inner layer with the outer layer chemically bonded interfacially to the rigid substrate so that the rigid substrate serves to reinforce the outer layer while retaining the texture and color of the exposed part.

15. A process according to claim 14, characterized in that the heat-activated crosslinked reaction monomer is carbodiimide.

16. A process according to claim 15, characterized in that at least one polyol contains one or more hydroxyl, or hydroxyl and carboxyl functional groups.

17. A process according to claim 16, characterized in that the first elevated temperature, the second elevated temperature, the elevated third temperature, and the elevated fourth temperature are all the same and range from about 140 ° F to about of 160 ° F. SUMMARY OF THE INVENTION A process for the manufacture of a structure as a panel to be mounted on a motor vehicle to form a part of the interior thereof. In accordance with this process, an outer layer (26) defining at least a portion of the exposed outer surface of the structure is prepared by applying a composition of thermoplastic polyurethane dispersed in water and a crosslinked, heat activated monomer on a surface of molding, and then dry the composition. Then, a quick reaction composition is sprayed onto an inner surface of the outer layer while the outer layer is retained on the mold or molding surface to form an inner layer of the polyurethane elastomer (28), which is chemically bonded interfacial to the outer layer. The inner layer with the external bonding layer chemically interfacing thereto is then bonded to the rigid substrate (22), so that the rigid substrate serves to reinforce the outer layer. The exposed outer surface of the panel-like structure simulates the appearance and texture of the real skin, while the inner layer and an intermediate layer of optional semi-rigid polyurethane foam (44) provides a feeling of compression to the exposed part of the skin. the outer layer.