CZ261699A3 - Process for producing articles for decoration of automobile interior with surface layer of integral light-weight stable polyurethane elastomer - Google Patents

Abstract

In a method of manufacturing a panel-type structure (10), designed to be mounted in a vehicle to form in the interior thereof, the outer layer (26) defining at least a portion exposed outer surface (10a) of this structure (10) prepared by applying a water-dispersed mixture thermoplastic polyurethane and heat-activated reactive crosslinking monomer to the mold surface and then drying the mixture (44). Next fast-reacting mixture (42) spraying onto the inner surface (26b) of the outer layer (26) while the outer layer (26) is left on the mold surface to be molding a polyurethane elastomeric inner layer (28) bound chemically to the outer layer (26). An inner layer (28) having an outer layer (26) thereto chemically then bonded to the solid filtrate (22) so as to be rigid the substrate (22) serves to reinforce the outer layer (26). Exposed outer layer (26) of panel structure (10) mimics the look and feel of real leather while the inner layer (28) and optionally intermediate layer (30) semi-solid polyurethane cellular foam provides a compressibility feel to exposed portions of the outer layer (26).

Description

A method of manufacturing articles for interior decoration of an automobile with a coating of an integral lightweight, stable polyurethane elastomer

Technical field

The present invention relates to a method of manufacturing an interior vehicle article comprising a panel type structure designed to be mounted in an automobile interior.

a formed part of its interior and especially production of decorative elements inside cars, as j sou instrumentation panels, door panels and the door - mailboxes for glove. BACKGROUND OF THE INVENTION Decorative Ware inside cars, as j sou instrumentation panels, door panels, armrests, armrests

heads, floor brackets, knee rests and glove box doors are constructed using a soft decorative coating covering a rigid substrate that can be attached to the car body, with a foamed polyurethane padding between the decorative coating and the rigid substrate. The decorative coating is usually provided with a predetermined texture and color to imitate the look and feel of genuine leather.

The preparation of a self-supporting synthetic decorative article for the interior of an automobile having a two-layer decorative coating is described in International Application WO 93/23237, and in particular in Example 2 thereof. According to the method described in WO 93/23237, To prepare this interior decorative product, a dispersion polyurethane lacquer is first applied to the surface of the open mold as paint into the mold and then dried by evaporating the solvent. Thereafter, a two-component polyurethane elastomer skin tread surface is formed on the surface of the dried paint into the mold using special nozzles and application systems. Suitable spray nozzles and systems that can be used are described in U.S. Pat. Nos. 5,028,006 and 5,071,683. A polyurethane cellular foam layer is then prepared by spraying a polyurethane reaction mixture onto a skin tread polyurethane elastomer. Finally, a polyurethane or polyisocyanurate reaction mixture is applied to the opposite surface of the polyurethane cellular foam layer in order to obtain a solid plastic carrier.

The commercial merit of this known paint-containing two-layer coating in the form described in WO 93/23237 and the process for its production are negligible, as evidenced by the current commercial activities of Recticel, which owns WO 93/23237. Recticel does not use solvent-based lacquer in its commercial operations. Recticel even forbade its customers to use their color in the mold.

The use of a solvent-based lacquer as a mold lacquer only further complicates the method of preparation described in WO 93/23237 by several complications and inefficiencies. For example, these varnishes contain large amounts of volatile organic compounds. Due to the extremely flammable and explosive properties of volatile organic compounds, these lacquers are subject to strict government regulations. Tiby complied with these government regulations, often requiring additional and expensive equipment that is designed to ensure worker safety and protect against environmental pollution. For example, production facilities equipped to handle these varnishes must include special spraying equipment, separate and separate spraying equipment. adapted spraying zones and air purification equipment. Workers must also wear special protective and often bulky equipment that is fireproof and protects against exposure to unhealthy and unpleasant vapors.

Accordingly, there is a need to provide a method of manufacturing a panel-like structure that includes a multilayer decorative coating to produce a panel-like structure more efficiently and cost-effectively and in which the resulting panel-like structure has a high quality and skin appearance.

SUMMARY OF THE INVENTION

Therefore, it is an object of the present invention to solve the aforementioned problems associated with the prior art and the needs mentioned above. In accordance with the principles of the present invention, this object is achieved in a method of manufacturing a panel structure designed to be mounted in an automobile vehicle to form part of its interior. The panel-type structure comprises an outer layer defining an outer surface of the structure, at least a portion of which outer layer is exposed towards the interior of the vehicle and a rigid substrate defining the surface of the structure towards the interior. When the panel structure is mounted in an automobile, the substrate is hidden when viewed from the interior of the vehicle.

According to one embodiment of the method, at least the following steps are performed to prepare the panel structure. First, a water dispersed composition comprising at least one light-stable aliphatic thermoplastic polyurethane comprising one or more attached hydroxyl and / or carboxyl functional groups, a desirable coloring agent, and a heat-activatable reactive crosslinking monomer, a heated mold surface shaped to apply to define the corresponding arrangement outer layers. Heat-activated ··· ·······························

- 4 - ............

the reactive crosslinking monomer is preferably carbodiimide. The light-stable thermoplastic polyurethane and the heat-activatable reactive crosslinking monomer are heated, preferably by preheating the mold surface, and reacted so that the thermoplastic polyurethane crosslinks with the reactive crosslinking monomer. Second, the water-dispersed mixture is substantially dried while lying on the mold surface to form the exposed outer layer with the outer surface, at least a portion of which has the desired touch, color and panel structure. Third, a rapidly reacting mixture comprising at least one polyisocyanate and at least one polyol is sprayed onto the inner surface of the outer layer while on the mold surface to form an inner layer that comprises a polyurethane elastomer crosslinked with the polyurethane of the outer layer through unreacted functional groups of thermally activatable reactive crosslinker in the outer layer. Subsequently, a composite laminate having chemical bonds at the interface between the inner surface of the outer layer and the adjacent surface of the inner layer is obtained. Fourth, the inner layer and the outer layer are chemically bonded at the interface, i.e. the composite layered structure is joined to the rigid substrate so that the rigid substrate serves to reinforce the outer layer. Optionally, a soft cellular polyurethane foam layer may be formed between the inner layer and the rigid substrate. As a result, the panel structure retains the feel and color of the exposed portion, which may mimic the look and feel of real skin and the sense of squeezability that the inner layer and possibly the soft cellular foam insert layer impart to the outer layer.

The composite laminate fabricated in accordance with this embodiment exhibits excellent chemical, abrasion and decay resistance to external influences. Other suitable additives can also be incorporated into the composite to provide a low-reflectance and low-gloss surface for the composite, which •

of these panel structures is desirable. Further, both the inner and outer layers of the composite are characterized by excellent extensibility so that the composite can resist notches and bends during use without cracking in the top layer over a wide temperature range, such as from -30 ° C to 80 ° C.

These and other objects of the features and advantages of the invention will be apparent from the following detailed description taken in conjunction with the accompanying drawings, which illustrate by way of example the principles of the invention.

Overview of the drawings

The accompanying drawings illustrate the present invention, wherein the figures show the following:

Fig. 1 is a partial cross-sectional view with a dashed-out missing part of a complete vehicle door panel made by the method of the present invention; Fig. 2 is a perspective view of a complete vehicle instrument panel made by the method of the present invention; FIG. 2 is a cross-section taken along line III-III;

Fig. 4 is a cross-sectional view of a mold surface showing the step of applying a water-dispersed polyurethane composition to a mold surface that is heated to form an outer layer of crosslinked light-stable polyurethane in accordance with the present invention; similar to that of FIG. 4, showing the step of drying the outer polyurethane layer; FIG. 6 is a cross-sectional view similar to that of FIG. 5, showing the step of obtaining the inner layer by spraying a rapidly reacting mixture onto the inner surface of the outer layer; forms, ta ta · ta · ta · ta · ta · ta · ta · ta · ta · ta · ta · ta · ta · ta · ta · ta · ta · ta · ta · ta · ta · ta · ta · ta · ta · · Tatata ··· · · · ·

- 6 - ............

Fig. 7 is a cross-sectional view similar to Fig. 6 showing the step of removing the combination of inner and outer layers from the mold surface; Fig. 8 is a cross-sectional view of the second mold surface showing the step of obtaining a relatively rigid polyurethane cellular foam middle layer by applying the reaction mixture. Fig. 9 is a cross-sectional view showing the step of bonding the combination of inner and outer layers on the surface of the second mold to a preformed relatively rigid substrate disposed on the surface of the third mold.

DETAILED DESCRIPTION OF THE INVENTION

More specifically, with reference to the drawings, Figure 1 shows a panel structure generally designated 10, which in this case is a vehicle door panel that has been fabricated according to one embodiment of a method according to the principles of the present invention. The door panel 10 includes an upper frieze forming a window frieze 12 and an armrests forming part 14 which define an anchorage part 16 therebetween. The lower planar part forming a support base 18 for the lining forming part 20 attached thereto is located below the elbow-forming part backrest 14.

As can be seen from the cross-section of FIG. 1, the panel structure 10 has an outer surface 10a open towards the interior of the vehicle and an interior surface 10b which, when viewed from the interior of the vehicle, is hidden when the panel structure 10 is mounted in an automobile. The panel structure 10 comprises a rigid substrate 22 having one surface defining an inner surface 10b of the panel structure 10. The panel structure 10 further comprises a structure 10b further comprising: a. ··· · · · · · · · · · · · · · · · · · · · · · · · · · · · · ·

- 7 - ............

a laminate composite structure, generally designated 24, comprising an outer layer 26 defining at least a portion of the exposed outer surface 10a of the panel structure 10 and an inner layer 28. At least a portion of the outer layer 26 is exposed toward the interior of the vehicle while a portion of the outer layer may be hidden from view decorative or covering element. For example, in Figure 1, the lower planar portion 18 forming the backing substrate 26 is covered by the lining portion 20 and is therefore not exposed towards the interior of the vehicle.

As shown in FIG. 1, the inner layer 28, which is relatively thick compared to the outer layer 26, has an outer surface 28a adjacent to the inner surface 26b of the outer layer 26a and is chemically bound thereto. As further shown in Fig. 1, the rigid substrate 22, which is hidden from the interior of the vehicle when the panel structure 10 is mounted in an automobile, reinforces the outer layer 26 and inner layer 28. Finally, the intermediate layer 30 comprising a relatively rigid (or semi-rigid) polyurethane cell. a foam padding is positioned between the inner layer 28 and the rigid substrate 22.

As can be seen from FIG. 4, the method of the present invention utilizes a first mold component or portion 32 having a first mold surface 34 for manufacturing the above article. The first mold portion 32 is preferably formed of electrolytically deposited nickel onto a solid cast epoxy substrate that is removed secondary to the end of the deposition / cladding process to obtain a self-supporting mold capable of being mounted and actuated in the tool module. The surface 34 of the first mold is shaped to define an arrangement that substantially matches the desired configuration of the outer layer 26 and is grainy to define a texture that substantially matches the desired texture of the outer layer 26 and mimics real skin.

·· 999 · · 9 · · 9 9 9 9 9 9 · · 9999 9 9 9 9 • 9 9999 999 · ··· 999

999999 9 8 ·

- 8 - ............

Giant. 4 illustrates a first step of the present invention, and in accordance with this step, an outer layer 26 is obtained by applying, preferably spraying, a mixture 36 dispersed in water onto the surface 34 in the first mold. The water dispersed composition comprises at least one light-stable aliphatic thermoplastic polyurethane comprising one or more attached hydroxyl and / or carboxyl functional groups, at least one desired coloring agent, and at least one heat-activatable reactive crosslinking monomer. Carbodiimide (H-N = C = N-H), also known as cyanamide, is preferably used as this heat-activatable reactive crosslinking monomer. Other suitable crosslinking monomers, such as aziridine, may also be used.

Applying the water dispersed mixture 36 to the heated surface 34 of the first mold induces a chemical reaction between one or more bonded hydroxyl and / or carboxyl functional groups on the light-stable thermoplastic polyurethane and the heat-active crosslinking monomer, thereby producing a cross-linked light-stable polyurethane. The surface 34 of the first mold should be heated to a sufficient temperature to expedite the crosslinking reaction, but it should not be so high as to cause delamination of the mixture 36 with the surface of the mold 34. Preferably, the surface 34 of the first mold is heated to a temperature of about 140 ° F (60 ° C) to about 160 ° F (71.1 ° C). Heating the first mold surface 34 to such elevated temperature prior to application of the water dispersed composition 36 also serves to melt and disperse mold release agents, such as microcristal wax mold release agents, applied to the first mold surface 34. Thus, the mold release agent is prevented from accumulating in complicated granular detail of the surface 34 of the first mold.

The water-dispersed composition 36 may be prepared by drawing on a light-stable aliphatic thermoplastic polyurethane, and

Heat-activated reactive cross-linking monomer from separate storage chambers in the form of continuous metered streams and mixing these components immediately before contact with the surface 34 of the first mold. Alternatively, the light-stable aliphatic thermoplastic polyurethane and carbodiimide component can be stably premixed or hot-potted and maintained at room temperature for up to 24 hours prior to use. This method is called hot-potting because the thermoplastic polyurethane and carbodiimide react slowly at room temperature in a pressure vessel (pot). If the mixture is maintained in such a pressure vessel at room temperature for more than 24 hours prior to application to the first mold surface 34, the resulting crosslinked light stable polyurethane exhibits poor solvent and abrasion resistance and elongation.

After shaping the crosslinked light stable polyurethane on the surface 34 of the first mold, the water dispersed mixture 36 now containing the crosslinked light stable polyurethane is substantially dried while leaving it on the surface 34 of the first mold to obtain the outer layer 26. As can be seen from FIG. 5, the crosslinked light-stable polyurethane may be exposed to heat sources 40 to evaporate water and solvent therefrom to form an outer layer 26 with an outer surface 26a adjacent the surface 34 of the first mold. Although not shown in Figure 5, such a heat source 40 is preferably integrated with the first mold 32, and preferably heats the first mold surface 34 to 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 desired feel, color, and granular configuration of the panel structure 10. The outer layer 26 generally has a thickness ranging from about 1.0 mil to about 1.5 mil (i.e., about 0.001 inch to about 0 mil). 0015 inch or from about 0.0025 cm to about 0.0038 cm).

Φ Φ φ »· · φ φ φ φ φ φ φ φ φ φ φ φ φ φ φ φ φ • • • • • • • • ........ ........ ........

The particular colorant selected may directly affect the desired thickness of the outer layer 26. Darker colors such as gray and green usually require only a small film thickness to conceal the color of the hidden inner layer 28, while lighter colors such as red and yellow usually dictate the need for relatively greater thickness to provide an opaque, non-transparent outer layer 26 that hides the inner layer 28 so that it is not visible.

Thereafter, an inner layer 28 is formed from the polyurethane elastomer as shown in FIG. 6 by spraying a rapidly reacting mixture 42 onto the inner surface 26b of the outer layer 26 while leaving the outer layer 26 on the first mold surface 34 in a substantially anhydrous state. The fast-reacting composition 42 comprises at least one polyisocyanate and at least one polyol, which interact with each other to form a polyurethane elastomeric inner layer 28. As used herein, the term elastomer herein includes a flexible polymeric composition that can stretch under moderate tension and have a relatively high strength tensile and memory, so that when the tension is released, the elastomer retracts and returns to its original dimensions or to dimensions substantially similar to its original dimensions.

In addition to being reactive with the polyisocyanate component, the polyol component of the rapidly reacting mixture 42 may comprise one or more attached hydroxyl and / or carboxyl functional groups that are highly reactive with unreacted carbodiimide functional groups in the outer layer 26 that have not reacted with the bound polyurethane functional groups. outer layers 26. Unreacted carbodiimide functional groups penetrate into the inner layer 28 and react with the attached functional groups of the polyol component. As a result, carbodiimide crosslinks the polyurethane of the outer layer 26 with the polyurethane elastomer of the inner layer 28, thereby forming at the φφ φφφφ

J · φ φφφ · · φ · φ · · φφ φφ

ΦΦΦ interface the chemical bond between the inner surface 26b of the outer layer 26 and the adjacent outer surface 28a of the inner layer 28. This provides the laminated composite structure 24. When crosslinking is performed under optimal crosslinking conditions, the edges between the outer layer 26 and the inner layer 28 of the laminated composite structure 24 may be visually bland; such that the transition phase appears at the interface of both layers. As mentioned herein, the chemical bonds at the interface include, but are not limited to, those crosslinking reactions in which the edge at the interface between the outer layer 26 and the inner layer 28 is visually indistinguishable and inseparable.

Generally, measures must be taken to ensure proper chemical bonding at the interface between the inner surface 26b of the outer layer 26 and the adjacent outer surface 28a of the inner layer 28. For example, once the carbodiimide is activated by heat, the crosslinking reaction between carbodiimide and lateral is completed. bonded hydroxyl and / or carboxyl reactive groups of the thermoplastic polyurethane in minutes, with substantially no residual reactive sites in the carbodiimide to crosslink the polyurethane of the outer layer 26 with the polyol component of the rapidly reacting mixture 42. Therefore, a generally fast-reacting mixture 42 should be sprayed within six minutes and preferably within two to four minutes of the completion of the deposition of the water-dispersed mixture 36 on the surface 34 of the first mold. Substantial delays in spraying of the fast-reacting mixture 42 can also cause the outer layer 26 to precipitate and delaminate from the surface 34 of the first mold. As a result of the delamination, the outer layer 26 will not have a shape that corresponds to the configuration of the surface 34 of the first mold and the entire composite 24 will have to be discarded.

On the other hand, if the thermoplastic polyurethane in the water dispersed mixture 36 is not given enough time to crosslink.

Before the fast-reacting mixture is sprayed onto it 42 • • • • • • • · · · · · · · · · · · · · · · · · · · · · · · · · · · The polyol component of the rapidly reacting mixture 42 can undergo a condensation reaction with unreacted hydroxyl and / or carboxyl functional groups of the polyurethane outer layer 26 and form ester or other bonds. Since some formulations of these bonds may advantageously improve chemical bonding at the interface, the condensation reactions release water, which in excess amounts may act as a blowing agent and undesirably increase the porosity of the inner layer 28 and disrupt the chemical bonding at the interface.

Chemical interface bonding is further improved when the highly reactive polyol and polyisocyanate component 42 is rapidly stored in separate storage chambers and the components are sprayed onto the inner surface 26b of the outer layer 26 to prevent contact between the components do not spray. A suitable double-nozzle spray mechanism to accomplish this is described in U.S. Patent Nos. 5,028,006 and 5,071,683. By keeping the two components separate until immediately after spraying, a portion of the polyol reacts with carbodiimide (and hydroxyl and / or carboxyl free compounds). functional groups of the thermoplastic polyurethane) before all the polyol can fully react with the polyisocyanate.

Further, in view of the hygroscopic nature of the polyisocyanate component of the rapidly reacting composition 42, it is important that the outer layer and the surrounding atmosphere (i.e., moisture levels) are substantially anhydrous during this spraying step in order to obtain a strong chemical bond at the interface. Some moisture may be retained in the outer layer 26; however, the concentration of this moisture should not be so large as to allow water to significantly interfere with the reaction between the polyol and polyisocyanate components of the rapidly reacting mixture 42. Adverse reactions between water

And a polyisocyanate may disrupt the stoichiometric balance between the polyol and the polyisocyanate and leave localized deposits behind the composite structure of the unreacted polyol on the laminate

24. The water may also serve as a blowing agent reacting with the polyisocyanate to release carbon dioxide that imparts a cellular structure to the inner layer 28. Excessive amounts of water may also interfere with the crosslinking reaction via the polyol and residual carbodiimide reactive crosslinking reactive sites. of the monomer.

The rapidly reacting mixture 42 is preferably applied to the inner surface 26a of the outer layer 26 at elevated temperature to meet these objectives. Suitable temperatures to which component 32 of the first mold can be heated, for example, without limitation, range from about 140 ° F (60 ° C) to about 160 ° F (71.1 ° C).

The inner layer 28 may generally have a thickness ranging from about 40 mils to about 60 mils (i.e., from about 0.040 inches to about 0.060 inches; or from about 0.10 cm to about 0.15 cm).

Giant. 7 shows a further step of the invention. As seen in FIG. 7, the laminated composite structure 24 is demolded (i.e., removed) from the surface of the first mold. The demolding process is often relatively labor intensive, tedious and time consuming. The formation of cracks or unwanted pulling in the laminated composite structure 24 during demolding can irreversibly destroy the laminated composite structures 24 and thus require their rejection as scrap. These demolding and inefficiency problems are largely eliminated when the present invention is employed, since chemical bonding at the interface between outer layer 26 and inner layer 28 strengthens the laminated composite structure 24 by counteracting separation of outer layer 26 from inner layer 28 during demoulding processes.

In order to further increase release from the mold surface 34 of the first mold, the mold surface 34 can be pretreated with a release agent. Examples of release agents include, but are not limited to, high molecular weight microcrystalline waxes such as Chem-Trend PRC 7140, available from Chem-Trend Inc, Howell, Michigan, USA, or PRC 2006, also available from Chem- Trend Inc. Trend. These release agents dry rapidly on the heated mold, in about 5 to 10 seconds, and form a separation barrier between the granular surface of the mold 34 and the outer layer 26. Care should be taken to avoid accumulation of the release agent on the first mold surface 34 or excessive solids. Such accumulation or excessive solids tends to fill the depressions in the decorative granular surface 34 of the mold, thereby removing from the outer surface of the panel-like structure 10 an intricate, like hair-like appearance having the mold surface 34. Excessive use of release agents can further cause the agents to convert to the composite structure 24 from the first mold surface 34 during demolding, requiring additional washing and drying steps to remove them after demolding and hence to lose productivity.

After demolding from the first mold surface 34, the laminated composite structure 24, including the combination of the outer layer 26 and the inner layer 28, can be checked for defects using a light source (not shown) while placing the laminated composite structure 24 on a transparent substrate ( not shown). Such defects are typically present as cosmetic blemishes in the outer layer 26 and may include the presence of cracks and parts that are subject to rupture where there is insufficient thickness to withstand the strain associated with demolding or other steps

- 15 of the process, particularly in the joining step. If these defects are minor and isolated, these localized defects can be corrected by subsequently applying another water-dispersed mixture 36 to the outer layer 26. In addition, small cracks or thin areas can be repaired using a thermoplastic, thermoformable polyurethane tape on the backside 28b layered This will advantageously prevent the entire laminate structure 24 from being discarded as scrap. However, it should be noted that subsequent repair of the surface 26a by spraying is generally undesirable and its use should be minimized to repair local defects, since the subsequent over-spray repair can negate the grain appearance of the skin on the outer surface 26a of the outer layer 26 that has been transferred thereto from the surface 34 of the first mold.

As discussed in more detail below, the steps of demolding and inspecting the laminated composite structure 24s of the first mold surface 34 need not be performed immediately after the laminated composite structure 24 is formed. For example, the laminated composite structure 24 may optionally be maintained on the first mold surface 34 until the panel structure 10 is completed. .

After the laminated composite structure 24 has been demolded from the first mold surface 34 and checked, the laminated composite structure 24 is placed on the surface 52 of the second mold portion 50. As shown in FIG. 8, the second mold surface 52 is also shaped to define the corresponding configuration of the outer layer 26. The reactive mixture 44 for forming a semi-solid cell foam, such as a polyurethane semi-solid cell foam, is then applied to the inner surface 28b of the inner The reaction mixture 44 can be applied, for example, by using very intense stirring and by means of a mixing nozzle. The portion 50 forming the second mold is during

The deposition of the reactive mixture heats to a temperature generally in the range of about 40 ° C to about 60 ° C, and more preferably in the range of about 15 ° C to about 60 ° C. from about 40 ° C to about 50 ° C. The mixture 44, which is generally relatively viscous, is in the transition state of the reaction during application to the second mold forming portion 50 and begins to foam within seconds after application.

Although the desired thickness of the interlayer depends in part on the intended use of the panel structure 10, generally the interlayer has a thickness in the range of about 5 mm to about 12 mm.

Once the reactive mixture 44 has been applied to the laminate composite structure 24 positioned on the second mold surface 52, the cooperating portion forming the third mold component 60 that carries the foamed rigid substrate 22 moves into a cooperating relationship with the second mold forming portion 50 as shown in FIG. 9. The third mold portion 60 has a third mold surface 62 (FIG. 8) which is shaped to define the inner surface 10b of the panel structure 10. Then, the reactive mixture 44 is foamed and crosslinked, preferably by heat treatment approximately 110 ° F (43.3 ° C) and a cavity pressure of about 0.8 atm is formed to form the intermediate layer 30. The semi-rigid polyurethane cellular foam serves to bond the laminated composite structure 24 to the foamed rigid substrate 22 positioned on the surface 62 of the third mold. . The panel structure including the combination of the laminated composite structure 24, the rigid substrate 22, and the intermediate layer 30 can then be removed from the second mold portion 50 and the third mold portion 60 and other components such as the lining portion 20 can be attached.

In the broadest sense, some changes and modifications may be made to the process discussed above without departing from the scope of the invention. For example, the layered composite structure 24 and / or the intermediate layer 30 may be excluded from the concealed lower planar portion 18 that carries the lining (or other). · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · ·

17 parts that are hidden when viewed from the inside of the vehicle when the panel structure is mounted in an automobile) at the resulting panel structure 10 shown in Fig. 1, so that the lower planar portion 18 forming the backing substrate is characterized in that has a rigid substrate 22 adjacent to the lining portion 20.

According to another embodiment of the present invention, a non-foaming adhesive may be selected to bond the laminated composite structure 24 to the rigid substrate 22.

In another embodiment, optionally, a plurality of water-dispersed compositions containing different coloring agents may be applied to different portions of the panel structure to form individual coating colors. Where the selected color or colors is to be changed, it has been found in practice that a minimum weaning time (of the order of about 0.5 hours) is required.

According to yet another embodiment, the outer layer 26 may have a two-tone or multi-tone design. This variant embodiment can be realized, for example, by abrasive treatment of a part of the mold surface of the tools. The greater the degree of abrasive treatment, the dimmer the appearance of the outer layer 26. A matt color design may be particularly desirable for instrument panels, as the upper region of the instrument panel should generally have a lower gloss to reduce reflection and dazzling glitter.

Other process variations may be used, such as leaving the laminated composite structure 24 in the first mold portion 32 instead of demolding and transferring the structure 24 to the second mold portion 50 to perform the bonding step. In accordance with another variation of embodiments of the present invention, the laminated composite structure 24 may be returned to the first mold component 32 after it has been inspected and treated.

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According to another variation of the invention, a secondary or alternative heat source may be used to activate the reaction between the light stable aliphatic thermoplastic polyurethane and the heat activated reactive crosslinking monomer. For example, the water dispersed mixture 36 may be preheated before being applied to the first mold surface 34 such that the first mold surface 34 need not be heated to initiate the reaction between the heat-activatable reactive crosslinking monomer and the light-stable aliphatic thermoplastic polyurethane.

According to another embodiment of the present invention, the reactive mixture 44 for shaping the polyurethane semi-solid cellular foam 30 may be applied to the surface of the rigid substrate 22 instead of the laminated composite structure 24. Alternatively, the second mold portion 50 and the third mold portion 60 may be engaged defining a cavity between the inner surface 28b of the inner layer 28 and the outer surface of the substrate 22, wherein a reactive mixture 44 is then injected between the solid substrate 22 and the composite 24.

In order to elucidate the method of the present invention, the following discussion describes suitable and particularly suitable components and conditions of manufacture of the article of the invention and for carrying out the method of the invention.

The water dispersed composition 36 used to prepare the outer layer 26 comprises at least one light-stable aliphatic thermoplastic polyurethane, at least one desirable coloring agent, and at least one reactive crosslinking monomer. The light-stable aliphatic thermoplastic polyurethane is preferably prepared from a high molecular weight aliphatic thermoplastic polyurethane containing hydroxyl or

The carboxyl-linked functional groups are chemically reactive with carbodiimide. The average molecular weight of the thermoplastic polyurethane is preferably in the range of about 5000 to about 7000, more preferably about 6000. The thermoplastic polyurethane and carbodiimide can be obtained, for example, from C.F. Jameson & Company, Inc., Bradford, Mass., USA under the tradename JAMESON WVF SERIES FLEXCOAT IMC. The desired weight ratio of thermoplastic polyurethane to carbodiimide for this particular mixture is about 8 to 1 by volume (equivalent to a ratio of 1.44 thermoplastic polyurethane to 1.08 dry solids carbodiimide).

The water dispersed mixture 36 may be prepared by taking the thermoplastic polyurethane component as a colloidal solution in a solvent such as N-methyl-pyrrolidone, then dispersing the solution by adding water, a coloring agent and conventional additives, if desired. Sufficient water may be added such that the concentration of solvent in the water dispersed mixture 36 is about 13.9 wt% and about 35 wt% after drying.

Optionally, without limitation, other ingredients or combinations thereof may be used in the water dispersed mixture 36: heat and UV stabilizers, pH stabilizers to maintain the alkaline dispersion state, plasticizers, antioxidants, matting agents, detergents, colloidal preservatives for water. keeping the particles in suspension, carbon black, thixotropic agents (e.g., hydroxymethylcellulose) and fillers such as clay particles.

The water dispersed composition 36 may contain, for example, about 20 wt% to about 30 wt% solids, and more preferably about 24 wt% solids, about 10 wt% to about 80 wt% water, and more preferably about 50 wt% water and about 9 wt% to 15 wt%. % by weight of solvents, depending on the desired color and additives. Insufficient amount of water in mixture 36 can • φ φ * • • • • • • • φ φ φ φ φ φ φ φ φ φ φ φ φ

- 21 - ............

adversely affect the viscosity of the composition 36 and thereby adversely affect the use of the water dispersed composition 36 on the surface 34 of the first mold. On the other hand, an excessive amount of water in the composition 36 can significantly alter the sprayability and coating ability of the water-dispersed composition 36.

To the thermoplastic polyurethane solution is added a carbodiimide solution, which may include, for example, glycol ether acetate or xylene as a solvent. When combined and activated, the thermally reactive crosslinked monomer reacts primarily with the hydroxyl and / or carboxyl groups of the thermoplastic polyurethane while crosslinking the thermoplastic polyurethane with itself or with the polyol components of the rapidly reacting mixture 42.

Examples of polyisocyanates that may be selected for the rapidly reacting mixture 42 used to prepare the inner layer 28 include polyisocyanates having a closed aliphatic ring structure with side-linked -NCO groups, such as isophorone diisocyanate, which can be obtained from Recticel under the trade name ISOFAST. Also suitable is tetramethyl xylene diisocyanate, which is available from Texaco under the trade name TMXDI. Aromatic polyisocyanates that are not light-stable are more desirable than currently available aliphatic polyisocyanates because of their lower cost, more predictable reactivity and higher tear strength compared to light-stable aliphatic polyisocyanates.

Suitable polyols for this rapidly reacting mixture 42 include, but are not limited to, polyether polyols having average molecular weights ranging from about 220 to about 250 and containing one or more side-linked hydroxyl and / or carboxyl groups (in addition to the primary hydroxyl groups) which may · ta * * * * * * * * ta ta ta ta ta ta ta ta ta ta ta ta ta ta ta ta ta ta ta ta ta ta ta ta · · ·

- 22 - ............

chemically react with unreacted -NH carboimide functionalities and hydroxyl and / or carboxyl side-linked polyurethane functionalities of outer layer 26. An example of a polyol is POLYFAST from Recticel.

The quick reacting composition 42 may also contain suitable additives, including, but not limited to, any combination of the following: heat and UV stabilizers, pH stabilizers, antioxidants, matting agents, detergents, carbon black, chain extenders (eg, ethylene glycol) thixotropic agents (e.g., amorphous silicon) fillers such as clay particles and tin (II) tin catalysts (e.g., tin dibutyl laurate); and tertiary amines (e.g., diethanolamine) and small amounts of foaming agents such as water. In this regard, it should be noted that the condensation reaction between the polyol and polyisocyanate mixtures releases water, which reacts with the polyisocyanate to form carbon dioxide and thereby obtain an interlayer 30 cell structure. Accordingly, it can be made lightweight. a stoichiometric excess of polyol to form a semi-solid polyurethane cell foam.

The rigid substrate 22 may be selected from a material having the required strength to reinforce and retain the outer layer 26, inner layer 28, and intermediate layer 30. Suitable materials include any material with sufficient stiffness to allow the composite to be mounted in a vehicle substructure, including, for example, injection molded. thermoplastics such as, but not limited to, styrene-maleic anhydride (SMA), acrylonitrile-butadiene-styrene (ABS), polycarbonates (PC), ABS-PC alloy, reinforced reaction injection molded polyurethanes (RRIM), metals, metal alloys, wood-fiber composites or any combination thereof.

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- 21 - * ...........

when the method of the invention has been exemplified above in the exemplary embodiment of a door panel preparation, it is understood that the method is equally applicable to other panel structures, including, for example, instrument panels, armrests, headrests, floor brackets, knee rests and the glove box door. For example, the method of the present invention can be used to manufacture the instrument panel shown in the spatial projection and in section in FIG.

The instrument panel 100 is shown in section in FIG. 3 and comprises a rigid substrate 122, an outer layer 126, and an inner layer 128 (collectively laminated composite structure, generally designated 124), and an intermediate layer 130. .

Throughout this specification, the entire disclosures of US and other patents or patent applications mentioned or cited above are incorporated herein.

Thus, it is apparent that the objects and principles of the present invention have been fully achieved. It will be appreciated, however, that the above specific embodiments have been shown and described for the purpose of the present invention and may be changed without departing from these principles. Therefore, the present invention includes all variations, modifications and improvements within the spirit and scope of the appended claims.

Industrial applicability

The principles of the invention mentioned above are applicable to the manufacture of all types of panel structures, but are particularly applicable to instrument panels (also called instrument panels) and door panels.

In addition, the principles of the invention are applicable in the manufacture of panel structures for various types of vehicles, including passenger cars, trucks, box cars, vans and others.

Claims (17)

PATENT CLAIMS A method of manufacturing a panel type structure designed to be mounted in an automobile vehicle to form part of its interior, the panel type structure comprising an outer layer defining an outer surface of the structure, at least a portion of which is exposed towards the vehicle interior and a solid surface defining substrate an interior structure which is hidden when viewed from the interior of the vehicle when the panel structure is mounted in an automobile, comprising the steps of applying a water dispersed composition (36) comprising at least one light-stable aliphatic thermoplastic polyurethane comprising one or more side-linked groups selected from the group consisting of hydroxyl and carboxyl functional groups, at least one desired coloring agent, and a heat-activatable reactive crosslinking monomer to the surface (34) of the first mold form so as to define the corresponding arrangement of the outer layer (26), heating and thereby crosslinking to a light stable aliphatic thermoplastic polyurethane with a heat-activatable reactive crosslinking monomer, substantially drying the water-dispersed mixture (36) while lying on the surface (34) of the first mold; to form a exposed outer layer (26) with an outer surface (26a), at least a portion of which has the desired feel, color and configuration of the panel structure (10), spraying a fast-reacting mixture (42) containing at least one polyisocyanate and at least one polyol per an inner surface (26b) of the outer layer (26) while on the surface (34) of the first mold to form an inner layer (28) comprising a polyurethane elastomer crosslinked with the outer polyurethane 99 9999 • 99 9 9999 9999 9 9 9 · 9 9,999 9,999,999 999999 9 9 9 - 23 - ............ layer (26), through unreacted functional groups of the heat-activatable reactive crosslinking monomer, thereby forming chemical bonds at the interface between the inner surface (26b) of the outer layer (26) and the adjacent surface (28a) of the inner layer (28) and joining the inner layer (28) with an outer layer (26) chemically bound thereto, with a rigid substrate (22) such that the rigid substrate (22) serves to reinforce the outer layer (26) while maintaining the feel and color of the exposed portion. 2. The process of claim 1 wherein the heat-activatable reactive crosslinking monomer is carbodiimide. The method of claim 2, wherein the at least one polyol comprises one or more side-linked hydroxyl, carboxyl, or hydroxyl and carboxyl functional groups. The method of claim 3, further comprising the steps of: transferring the inner layer (28) with the outer layer (26) thereto at the interface chemically bonded to the surface (34) of the first mold to the surface (52) of the second mold and forming a rigid substrate (22) on the surface (62) of the third mold defining the inner a surface of the panel structure (10), the bonding step comprising applying a reactive mixture to the inner layer (28) with the outer layer (26) chemically bonded thereto while on the surface (52) of the second mold, the surface arrangement (52) a second mold and a third mold surface (62) such that the inner layer (28) with the outer layer (26) chemically bound thereto and the rigid substrate (22) together define a mold cavity for receiving the reactive mixture (44), ·· »··· - 25 9 9 · · · · · 9 9 9 9 9 9 9 9 9999 999 9 9 9 9 9 9 99 99 99 99 99 99 9 9 9 9 9 9 999 999 9 9 99 99 foaming the reactive mixture (44) to form a relatively rigid polyurethane cellular foam that attaches the rigid substrate (22) to the inner layer (28) with the outer layer (26) bound thereto, and wherein the outer layer (26) is provided with a compressible feeling of relatively rigid polyurethane foam and an inner layer (28). The method of claim 4, further comprising the steps of: transferring the inner layer (28) with the outer layer (26) chemically bound thereto, with the surface (52) of the second mold to the transparent surface of the support platform, detecting and reinforcing portions that may rupture on the inner layer (28) with the outer layer (26), chemically bound to the interface to prevent it from failing during this bonding step. A method according to claim 3, characterized in that this drying step is carried out by evaporating water from the mixture (36) dispersed in water. The method of claim 3, wherein the outer layer (26) has a thickness ranging from about 1.0 mil (0.025 mm) to about 1.5 mil (0.038 mm). The method of claim 3, wherein the inner layer (28) has a thickness ranging from about 40 mil (0.1 cm) to about 60 mil (0.15 cm). The method of claim 3, further comprising the step of pre-coating the surface (34) of the first mold with a release agent for removal from the microcristal wax molds. · ♦ · * * * * * * * * * * * 9 9 9 9 9 9 9 9 9 9 99 9 9 9 9 999 9 999 999 9 9 9 9 9 9 9 · - 27 - ............ The method of claim 3, wherein the at least one light-stable aliphatic thermoplastic polyurethane and the heat activated reactive crosslinking monomer are premixed and stably stored prior to this deposition step for at least 24 hours at room temperature. The method of claim 3, wherein the first mold surface (34) is heated during the spraying step. The method of claim 3, wherein the first mold surface (34) is shaped to define a corresponding configuration of the outer surface (10a) of the door panel. The method of claim 3, characterized in that the surface (34) of the first mold is shaped to match the configuration of the outer surface of the panel (100). is that to define the instrumentation A method of manufacturing a panel type structure designed to be mounted in an automobile vehicle to form part of its interior, the panel type structure comprising an outer layer defining an outer surface of the structure, at least a portion of which is exposed towards the interior of the vehicle and a solid substrate defining surface a structure towards the interior which is hidden when viewed from the interior of the vehicle when the panel structure is mounted in an automobile, comprising the steps of: first coating a mold release agent based on micro-crystalline wax, wherein the surface (34) of the first the molds are heated to a first elevated temperature to melt and disperse the microcrystalline wax release agent; - 27 • · · · · 99 3 9 9 9 9 9 9 99 99 99 9 9 · 9 9 • 99,999 9 9 9 Applying a water-dispersed composition (36) comprising at least one light-stable aliphatic thermoplastic polyurethane comprising one or more side-linked groups selected from the group consisting of hydroxyl and carboxyl functional groups, at least one desired coloring agent, and a heat-activatable reactive crosslinking agent a monomer onto a first mold surface (34) comprising a mold release agent based on microcristal wax dispersed thereon, wherein the first mold surface (34) is shaped to define a corresponding configuration of the outer layer (26), maintaining the first mold surface (34) at a second elevated temperature during this step of applying the water-dispersed mixture (36) thereby crosslinking to a light-stable aliphatic thermoplastic polyurethane with a heat-activatable reactive cross-linking monomer, substantially drying the water-dispersed with the copper (36) while lying on the first mold surface (34) by heating the first mold surface (34) to a third elevated temperature to form the exposed outer layer (26) with the outer surface, at least a portion having the desired feel, color and arranging the panel structure (10) by spraying a quick-reacting mixture (42) comprising at least one polyisocyanate and at least one polyol on the inner surface (26b) of the outer layer (26) while being on the first mold surface (34) heated to the fourth raised temperature to form an inner layer (28) comprising a polyurethane elastomer crosslinked with the polyurethane of the outer layer (26) through unreacted functional groups of the thermally activatable reactive crosslinking monomer and thereby forming chemical bonds at the interface between the inner surface (26b) of the outer layer (26) and an adjacent surface (28a) of the inner layer (28); - 28 99 ·· 99 ·· • 9 9 999 999 9999 99 9 9999 999 « 9,999 9,999,999,999 999999 9 9 9 joining the inner layer (28) with the outer layer (26), at the interface chemically bound thereto, by a rigid substrate (22) such that the rigid substrate (22) serves to reinforce the outer layer (26) while maintaining touch and color exposed parts. The method of claim 14, characterized by a heat activated reactive cross-linking carbodiimide. wherein the monomer is e The method of claim 15, wherein the at least one polyol comprises one or more side hydroxyl, carboxyl or hydroxyl and carboxyl functional groups. The method of claim 16, wherein the first elevated temperature, the second elevated temperature, the third elevated temperature, and the fourth elevated temperature are the same and range from about 140 ° F (60 ° C) to about 160 ° F (71 ° C). 1 ° C).