BACKGROUND OF THE INVENTION

Field of the Invention

[0001] The subject invention generally relates to engine covers for vehicle, and more specifically to multi-component engine covers including an overlay coupled to a heat resistant insert.

Description of the Related Art

[0002] There has been a recent push in certain industries, such as the automotive industry, to utilize polyurethane engine covers to replace other types of plastic covers to protect engines. One of the limiting factors for the use of full polyurethane engine covers is that polyurethane engine covers degrade at temperatures of about 150 degrees Celsius. Such temperature conditions are problematic, in that the operation of engines utilizing these covers generate sufficient heat to create localized "hot spots" on the covers that degrade.

[0003] One solution to mitigate this heat degradation in polyurethane covers is to attach heat resistant tape to the inner surface of the polyurethane engine cover in areas that correspond to the localized hot spots. Unfortunately, the use of heat resistant tape is expensive and the manufacturing required to attach the tape to the polyurethane is both time consuming and technically challenging.

[0004] Accordingly, the present invention seeks to provide a more economical and easier solution to mitigate the issue of localized hot spots for polyurethane engine covers.

SUMMARY OF THE INVENTION AND ADVANTAGES

[0005] The subject application provides a multi-component engine cover for covering an engine of a vehicle. The multi-component engine cover includes an inner surface positioned adjacent to the engine and an outer surface opposite the inner surface. The inner surface of the multi-component engine cover includes a heat resistant insert comprising a melamine foam. The multi-component engine cover also includes an overlay coupled to the heat resistant insert that defines the outer surface. The overlay comprises polyurethane, and in certain instances comprises a polyurethane foam.

[0006] The heat resistant insert is adapted to withstand a temperature greater than a heat degradation temperature of the overlay but less than the heat degradation temperature of the melamine foam during operation of the engine.

[0007] In further embodiments, the overlay extends along a part of the inner surface of the multi-component engine cover. In still further embodiments wherein the overlay extends along a part of the inner surface, the inner surface of the multi- component engine cover includes at least two heat resistant inserts, wherein each respective one of the at least two heat resistant inserts separated along the inner surface by the overlay.

[0008] The subject application also provides associated methods for forming the multi-component engine cover in accordance with any embodiment described above.

[0009] The subject application thus provides a solution for addressing the heat degradation issues associated with the use of a single component polyurethane engine cover to engines by positioning the heat resistant insert along portions of the heat resistant cover that receive temperatures during the operation of the engine that are greater than the heat degradation temperature of the polyurethane cover. The subject application provides a simple, single step forming process that is repeatable and efficient. Further, because the melamine foam is located along portions of, or the entirety of, an inner surface of the multi-component engine cover, the aesthetically pleasing exterior surface, which includes the overlay, is not affected.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 provides an embodiment to the present disclosure which is a perspective view of a vehicle having an engine and a multi-component engine cover in accordance with one embodiment of the present invention;

[0011] Figure 2 is a perspective view of the engine cover of Figure 1 in accordance with the one embodiment of the present invention;

[0012] Figure 3 is a bottom view of the engine cover of Figure 2;

[0013] Figure 4 is a bottom view of the engine cover of Figure 2 in an alternative embodiment of the present invention; [0014] Figure 5 provides an embodiment to the present disclosure which illustrates a section view of a mold used to form the multi-component engine cover in accordance with one exemplary method of the present invention;

[0015] Figure 6 illustrates the mold according to Figure 5 in which multiple inserts have been introduced with the cavity of the mold; and

[0016] Figure 7 illustrates the mold of Figures 5 and 6 during the introduction of the isocyanate component and isocyanate reactive component within the remainder of the cavity of the mold.

DETAILED DESCRIPTION OF THE INVENTION

[0017] The subject application is directed to a multi-component engine cover 20 for covering an engine 15 of a vehicle 10. The engine cover's 20 primary function is to protect the engine 15, as well as to protect the proximal components 16 of the vehicle 10 that are located within the interior region 18 of the vehicle 10 in a location underneath the hood (removed from Figure 1 for illustrative purposes) of the vehicle 10, both during and after operation of the vehicle 10. Such protection can also include providing heat protection to the proximal components 16 of the vehicle 10 during operation of the engine 15. In addition, the engine cover 20 also functions to protect individuals both during and after operation of the engine 15 of the vehicle 10, particularly when such individuals are viewing the interior region 18 of the vehicle 10 or when such individuals are positioned within the passenger compartment 17 of the vehicle 10. Such protection can also include protection from noise associated with the engine to the passenger compartment 17 of the vehicle 10 during operation of the engine 15, as well as providing heat protection to individuals from contacting the engine 15 when the hood of the vehicle is opened and the interior region 18 is exposed. Still further, the engine cover 20 provides an aesthetic function for the vehicle 10 as well, in that the engine cover 20 provides an aesthetically pleasing outer covering for the engine 15 for viewing by individuals.

[0018] As best shown in Figures 2 and 3, the multi-component engine cover 20 includes an inner surface 22 positioned adjacent to the engine 15 and an outer surface 24 opposite the inner surface 22. The outer surface 24 corresponds to the aesthetic outer surface of the engine cover 20 that is visible within the interior region 18 when the engine cover 20 is coupled over the engine 15, while the inner surface 22 corresponds to a surface that is positioned adjacent to and over the engine 15 and is typically not visible to individuals viewing the interior region 18 of the vehicle 10 and therefore provides, nor requires, aesthetic functionality.

[0019] The inner surface 22 of the multi-component engine cover 20 includes one or more heat resistant inserts 30 that are positioned, respectively, on the multi- component engine cover 20. The heat resistant inserts 30 provide enhanced heat degradation resistance to the engine cover 20 associated with heat generated during operation of the vehicle's engine 15.

[0020] As shown in Figures 2 and 3, one representative embodiment includes three distinct heat resistant inserts 30A, 30B, and 30C. However, in other embodiments, the number of inserts 30 can vary be as little as one insert 30 (i.e., a single insert) to as many as ten or more inserts 30. For the purposes of describing embodiments of the invention having a single insert 30, such single inserts 30 generally correspond to one of the respective distinct heat resistant inserts 30A, 30B, and 30C described and illustrated in Figures 2 and 3, and thus the description of the aspects of engine covers having a single insert 30 is contained within the description of Figures 2 and 3 further below.

[0021] Each respective insert 30 includes an inner side surface 32 and an opposing outer side surface 34 and one or more side surfaces 36 connecting the inner side surface 32 to the outer side surface 34. Collectively, the inner side surface 32, the outer side surface 34, and the one or more side surfaces 36 of each respective insert 30 define a three-dimensional shape.

[0022] Depending upon the positioning and shape of the respective insert 30, 30A, 30B, 30C, as will be described in further detail below, at least one of the inner side surface 32 or the one or more side surfaces 36 at least partially define the inner surface 22 of the multi-component engine cover 20. For example, in embodiments including multiple heat resistant inserts 30, such as the three distinct heat resistant inserts 30A, 30B, and 30C as shown in Figures 2 and 3, the size and shape of each respective insert 30 A, 30B, and 30C may vary, as does the respective surface or surfaces of the insert that define the inner surface 22 of the formed multi-component engine cover 20. Still further, the respective orientation of the heat resistant inserts 30A, 30B, and 30C relative to the ground may be different from one another, with orientation generally defined by a plane extending along the length of the respective insert 30A, 30B, and 30C. [0023] For example, in multi-component engine covers 20 including a single heat resistant insert, represented as a generally vertically-extending heat resistant insert 30A (as shown in Figures 2 and 3) that extends in a direction generally vertically to the ground when installed in the vehicle 10, the inner side surface 32A of the heat resistant insert 30A at least partially defines the inner surface 22 of the multi- component engine cover 20. Similarly, in multi-component engine covers 20 including a single L-shaped heat resistant insert represented as the L-shaped heat resistant insert 30B (as shown in Figures 2 and 3), which extends along its length in two different orientations relative to the ground with each side length generally normal to the other side length, the inner side surfaces 32B and 32C of the L-shaped heat resistant insert 30B at least partially defines the inner surface 22 of the multi- component engine cover 20 in another embodiment. Still further, in multi-component engine covers 20 including a single generally heat resistant insert, represented as a generally horizontally-extending heat resistant insert 30C shown in Figures 2 and 3 that extends in a direction generally horizontally with respect to the ground when installed on the vehicle 10, the inner side surface 32 of the generally horizontally- extending insert 30C at least partially defines the inner surface 22 of the multi- component engine cover 20. Accordingly, in the embodiment shown in Figures 2 and 3 which includes each of the three heat resistant inserts 30A, 30B and 30C as shown, the inner surface 22 of the multi-component engine cover 20 is at least partially defined by the inner side surface 32A of heat resistant insert 30A, the inner side surfaces 32B and 32C of the heat resistant insert 30B, and the inner side surface 32D of the heat resistant insert 30C.

[0024] While insert 30A in Figures 2 and 3 is illustrated as being generally vertical relative to the ground, and insert 30C is illustrated as being generally horizontal relative to the ground, such representation is not meant to be limiting to those respective orientations. Thus, for example, the inserts 30A and 30C that are described as generally vertical and horizontal may positioned at any angle relative to the ground when mounted within the interior region 18 of the vehicle 10.

[0025] The multi-component engine cover 20 also includes an overlay 50 coupled to the heat resistant insert 30, 30A, 30B, 30C. In certain embodiments, the coupling of the overlay 50 to the heat resistant insert 30, 30A, 30B, 30C is wherein the overlay 50 is positioned adjacent to the heat resistant insert 30, 30A, 30B, 30C, while in further embodiments the coupling is defined wherein the overlay 50 is mechanically or chemically adhered to the heat resistant insert 30, 30A, 30B, 30C. In these embodiments, the mechanical adherence may be in the form of entanglement of the overlay 50 with the heat resistant insert 30, 30A, 30B, 30C. In addition, or in the alternative, the chemical adherence of the overlay 50 and the heat resistant insert 30 may be in the form of a molecular interaction without chemical bonding (i.e., without covalent bonding) between the overlay 50 and the heat resistant insert 30 (such as in the form on hydrogen bonding) and/or in the form of chemical/covalent bonding between the overlay 50 and the heat resistant insert 30, 30A, 30B, 30C.

[0026] The overlay 50 is formed as a three-dimensional object that, together with the one or more heat resistant inserts 30, 30A, 30B, 30C, defines the size and shape of the multi-component engine cover 20. The overlay 50 includes an exterior surface 52 and an interior surface 54 and an edge surface 56 connecting the exterior surface 52 to the interior surface 54. The exterior surface 52 defines the outer surface 24 of the multi-component engine cover 20.

[0027] In certain embodiments, the interior surface 54 of the overlay 50 may be further subdivided into multiple interior surfaces that are each respectively coupled to a corresponding respective surface of a respective one of the heat resistant inserts 30, 30 A, 30B, 30C. As described hereinafter, the term "coupled to" as it relates to the overlay 50 and insert 30 refers to the relationship between the adjacent surfaces of the overlay 50 and respective insert 30, 30A, 30B, 30C and is intended to include "positioned adjacent to", mechanically adhered to", and/or "chemically adhered to."

[0028] Accordingly, in certain embodiments, the interior surface 54 of the overlay 50 may be subdivided into a first interior surface 55 and a second interior surface 56. In these embodiments, the first interior surface 55 of the overlay 50 is coupled to the outer side surface 34 of a respective one of the heat resistant inserts 30, 30A, 30B, 30C. Further, in these embodiments, the second interior surface 56 is coupled to one or more of the side surfaces 36A-D of the heat resistant inserts 30, 30A, 30B, 30C.

[0029] In certain embodiments, as best shown in Figure 4, the interior surface 54 of the overlay 50 also is subdivided into a third interior surface 57 having an opposing inner surface 58 and edge surface 59 connecting the third interior surface 57 to the opposing inner surface 58. In this embodiment, the opposing inner surface 58 is coupled to the side surface 36E of the heat resistant insert 30A and 30B, respectively. [0030] In certain embodiments, the overlay 50 comprises polyurethane. In certain embodiments, the polyurethane overlay 50 is formed as the reaction product of an isocyanate-reactive component and an isocyanate component.

[0031] The isocyanate-reactive component is preferably a polymer that includes one or more hydro yl groups (OH- functional groups), or more commonly referred to as a hydroxyl-functional polymer. The isocyanate component is a polymer that includes one or more isocyanate groups (NCO groups) that react with the hydroxyl groups to form carbamate (i.e. urethane) links.

[0032] In certain embodiments, the hydroxyl-functional polymer is a hydroxyl- functional polyether (i.e., hydroxyl-functional polyether-group containing polymers)

[0033] The hydroxyl-functional polyether used as one of the reactants in forming the polyurethanes of the present invention are polyether polymers that include one or more hydroxyl-functional groups, typically at least two OH-functional groups. Accordingly, the hydroxyl-functional polyether are polyether polymers having one OH-functional group (i.e., a polyether monol), two OH-functional groups (i.e., a polyether diol), three OH-functional groups (i.e., a polyether triol), four OH- functional groups (i.e., a polyether tetrol), polyether-group containing polymers having more than four OH-functional groups, and combinations thereof. The hydroxyl functionality of these hydroxyl-functional polyethers is typically expressed in terms of an average functionality of all of the respective polymer chains present in the collective hydroxyl-functional polyether blend.

[0034] Hydroxyl-functional polyethers having an average of two or more OH- functional groups per molecule are sometimes alternatively referred to as polyether polyols, which are typically formed as the polymeric reaction product of an organic oxide and an initiator compound containing two or more active hydrogen atoms. The active hydrogen compound in the presence of a base catalyst initiates ring opening and oxide addition, which is continued until the desired molecular weight is obtained. If the initiator has two active hydrogens, a diol results. If a trifunctional initiator such as glycerine is used, the oxide addition produce chain growth in three directions, and a triol results.

[0035] The hydroxyl-functional polyether can be any type of hydroxyl-functional polyether known in the art. The hydroxyl-functional polyether can be non-ethoxylated or ethoxylated. In addition, the hydroxyl-functional polyether can be short chain, low molecular weight hydroxyl-functional polyether having one or more OH-functional groups. Particularly suitable hydroxyl-functional polyether or polyethers for use in the polyurethanes include, but are not limited to, products obtained by the polymerization of a cyclic oxide, for example ethylene oxide (EO), propylene oxide (PO), butylene oxide (BO), or tetrahydrofuran in the presence of initiator compounds having one or more active hydrogen atoms. Suitable initiator compounds including a plurality of active hydrogen atoms for use in obtaining hydroxyl-functional polyethers include water, butanediol, ethylene glycol, propylene glycol (PG), diethylene glycol, triethylene glycol, dipropylene glycol, ethanolamine, diethanolamine, triethanolamine, toluene diamine, diethyl toluene diamine, phenyl diamine, diphenylmethane diamine, ethylene diamine, cyclohexane diamine, cyclohexane dimethanol, resorcinol, bisphenol A, glycerol, trimethylolpropane, 1,2,6-hexanetriol, pentaerythritol, and combinations thereof.

[0036] Other suitable hydroxyl-functional polyether or polyethers include polyether diols and triols, such as polyoxypropylene diols and triols and poly(oxyethylene-oxypropylene)diols and triols obtained by the simultaneous or sequential addition of ethylene and propylene oxides to di- or tri-functional initiators. Copolymers having oxyethylene contents of from about 5 to about 90% by weight, based on the weight of the polyether polyol component, of which the polyether polyols may be block copolymers, random/block copolymers or random copolymers, can also be used. Yet other suitable hydroxyl-functional polyethers include polytetramethylene ether glycols obtained by the polymerization of tetrahydrofuran.

[0037] Particularly suitable hydroxyl-functional polyether or polyethers for use include those based on a totally heteric (or random) EO, PO structure, or those having heteric, but uniform blocks of EO and PO, e.g. blocks comprising EO and blocks comprising PO. As yet another suitable example, the hydroxyl-functional polyether can have heteric blocks and uniform blocks of EO and PO, e.g. blocks comprising all EO or PO and blocks comprising random EO, PO. Still further, in certain examples, the hydroxyl-functional polyether can be heteric or random copolymers of EO and PO which are endblocked with either EO or PO. One particularly suitable hydroxyl- functional polyether comprises a polyether-triol having ethylene-oxide terminal groups.

[0038] Suitable non-limiting commercial hydroxyl-functional polyether or polyethers having an average of two OH-functional groups per molecule, sometimes referred to as polyether diols, for use in the present invention are based upon the propoxylation and/or ethoxylation of diethylene glycol, dipropylene glycol, ethylene glycol, or propylene glycol include Pluracol ^® P410R, 1010, 2010, 1062, and 1044, each commercially available from BASF Corporation of Florham Park, New Jersey. In particular, Pluracol ^® P410R, 1010, 2010, and 1044 are PO-containing hydroxyl- functional polyether diols, while Pluracol ^® 1062 is a PO-containing hydroxyl- functional polyether diols endcapped with EO.

[0039] Suitable non-limiting commercial hydroxyl-functional polyether or polyethers having an average of three OH-functional groups per molecule, sometimes referred to as polyether triols, for use in the present invention are based on the propoxylation and/or ethoxylation of glycerin or trimethyolpropane include Pluracol ^® GP430, GP730, 4156, 2090, and 816, each commercially available from BASF Corporation of Florham Park, New Jersey. In particular, Pluracol ^® GP430 and GP730 are PO-containing hydroxyl-functional polyether triols, Also, Pluracol ^® 2090 and 816 are a PO-containing hydroxyl-functional polyether triol endcapped with EO, while Pluracol ^® 4156 is a pure heteric hydroxyl-functional polyether triol.

[0040] Suitable non-limiting commercial hydroxyl-functional polyether or polyethers having an average of four OH-functional groups per molecule, sometimes referred to as polyether tetrols, propoxylation and/or ethoxylation of toluene diamine, ethylene diamine, and pentaerythritol for use in the present invention include Pluracol ^® 735, 736 and PEP 500 and Quadrol, each commercially available from BASF Corporation of Florham Park, New Jersey. In particular, Pluracol ^® 735 and 736 toluene diamine initiated hydroxyl-functional polyether polyols based on PO, Pluracol ^® PEP 500 is a pentaerythritol-initiated heteric, and Quadrol is an ethylene diamine initiated hydroxyl-functional polyether polyols based on PO.

[0041] One suitable non-limiting commercial higher hydroxyl-functional polyether for use in the present invention are based on sucrose, sorbitol or combinations thereof alone or in combination with other initiators is Pluracol ^® SG360 (based on sucrose and glycerin), commercially available from BASF Corporation of Florham Park, New Jersey.

[0042] In certain of these embodiments, the hydroxyl-functional polyether or polyethers for use in the present invention have a weight average molecular weight (Mw) ranging from 180 to 6,500 g/mol, as measured by gel permeation chromatography (GPC) or nuclear magnetic resonance (NMR) previously calibrated using a calibration curve based on mono-dispersed polystyrene standards. [0043] In certain embodiments, a combination of two or more hydroxyl- functional polyethers for use in the present invention can be used, with each one of the two or more hydroxyl-functional polyethers having the same or a different weight average molecular weight within the range of 180 to 6,500 g/mol described above. Thus, for example, the hydroxyl-functional polyethers used may include a first hydroxyl- functional polyether having a weight average molecular weight ranging from 180 to 6,500 g/mol and a second hydroxyl-functional polyether different from the first hydroxyl-functional polyether also having a weight average molecular weight ranging from 180 to 6,500 g/mol. Representative examples of the two or more hydroxyl- functional polyethers include those described in the paragraphs above.

[0044] In even further embodiments, in addition to the hydroxyl-functional polyether, the isocyanate-reactive component further includes a styrene-acrylonitrile graft polyol. Exemplary styrene-acrylonitrile graft polyols utilized are copolymers which are from 25-40% solids dispersed in a polyether triol, and typically have viscosities ranging from 2500-7000 mP ^' s. Exemplary polyether triols include those described above.

[0045] In certain embodiments, in addition or in place of the hydroxyl-functional polyether, the isocyanate-reactive component may by in the form of another hydroxyl- functional polymer, including but not limited to hydroxyl-functional acrylics.

[0046] Suitable hydroxyl-functional acrylics are obtained by free-radical polymerization of acrylate and methacrylate esters and styrene (such as ethyl acrylates (EA) or butyl acrylates (BA), acrylic acid (AA), methyl methacrylate (MMA), or styrene (ST)). Hydroxyl functionality is introduced by adding ethylenically unsaturated monomers having at least one free hydroxyl group, typically hydroxy- functional acrylates (HFAs) such as 2-hydroxyethyl acrylates (HEA) or 4- hydroxybutyl acrylates (HBA), to the monomer blend. One exemplary 100% solids acrylic-modified polyether polyol in Joncryl 569, commercially available from BASF Corporation of Florham Park, New Jersey, having a hydroxyl number of 140 mg KOH/g.

[0047] As also noted above, the polyurethane of the present invention also includes an isocyanate component as one of its reactants. The isocyanate component typically has an average functionality of from about 1.5 to about 3.0, more typically from about 2.0 to about 2.8, and yet more typically about 2.7. The isocyanate component also typically has an NCO content varying from a few weight percent to around 50 weight percent, depending upon the isocyanate component. For aliphatic isocyanates, the NCO content may range from about 18 to 30 wt.%. For aromatic isocyanates, the NCO content may range from 25 to 50 wt.%. For isocyanate prepolymers the range may vary from 1 to 47 wt.%, more typically 1-29 wt.%. For hexamethylene diisocyanate (HDI), the isocyanate component typically has an NCO content of from about 20 to about 23.5 wt.%. For methylene diphenyl diisocyanate (MDI), the isocyanate component typically has an NCO content of from about 29 to about 34 wt.%. For toluene diisocyanate (TDI), the isocyanate component typically has an NCO content of from about 45 to about 50 wt. %.

[0048] Suitable isocyanates for use in the isocyanate component include, but are not limited to, aromatic or aliphatic isocyanate- group containing compounds such as methylene diphenyl diisocyanate (MDI), polymethylene polyphenylisocyanate (PMDI), hexamethylene diisocyanate (HDI), an isocyanate-terminated prepolymer, a carbodiimide polymer having unreacted isocyanate groups (i.e., free (pendent) NCO groups), and any combinations thereof.

[0049] The isocyanate-terminated prepolymer, when present in the isocyanate component of the second composition, is generally the reaction product of an isocyanate and an active hydrogen-containing species and is formed by various methods understood by those skilled in the art or can be obtained commercially from a manufacturer, a supplier, etc.

[0050] With regard to the isocyanate used to form the isocyanate-terminated prepolymer in this first method, the isocyanate may include one or more isocyanate (NCO) functional groups, typically at least two NCO functional groups. Suitable isocyanates, for purposes of the present invention for use in forming the isocyanate- terminated prepolymer include, but are not limited to, conventional aliphatic, cycloaliphatic, aryl and aromatic isocyanates.

[0051] In certain embodiments, the isocyanate of the isocyanate-terminated prepolymer of the second composition is selected from the group of methylene diphenyl diisocyanate (also sometimes referred to as diphenylmethane diisocyanate, MDI, or monomeric MDI), polymethylene polyphenyl diisocyanate (also sometimes referred to as polymeric diphenylmethane diisocyanate, polymeric MDI or PMDI), and combinations thereof. MDI exists in three isomers (2,2'-MDI, 2,4'-MDI, and 4,4'- MDI) however, the 4,4' isomer (sometimes referred to as Pure MDI) is most widely used. For the purposes of the present invention, the term "MDI" refers to all three isomers unless otherwise noted. In these embodiments, MDI and PMDI are desirable for use over toluene diisocyanate (TDI) due to their lower reactivity. Still further, MDI and PMDI have lower vapor pressure than TDI, allowing safer handling prior to and during application.

[0052] In certain embodiments, the isocyanate-terminated prepolymer of the second composition comprises a blend of PMDI and quasi-prepolymers of 4,4'- methyldiphenyldiisocyanate. Specific examples of suitable isocyanate-terminated prepolymers, for purposes of the present invention, are commercially available from BASF Corporation of Florham Park, NJ, under the trademark LUPRANATE ^® , such as LUPRANATE ^® MP102. It is to be appreciated that the system can include a combination of two or more of the aforementioned isocyanate-terminated prepolymers.

[0053] Exemplary diisocyanates that may be used in forming the polycarbodiimide include, but are not limited to: MDI (in any the three isomers (2,2'- MDI, 2,4'-MDI, and 4,4'-MDI); m-phenylene diisocyanate; 2,4-toluene diisocyanate; 2,6-toluene diisocyanate; hexamethylene diisocyanate; 1 ,4-phenylene diisocyanate; tetramethylene diisocyanate; cyclohexane-l,4-diisocyanate; hexahydrotoluene diisocyanate; methylenediisocyanate; 2,6-diisopropylphenyl isocyanate; m-xylylene diisocyanate; dodecyl isocyanate; 3,3'-dichloro-4,4'-diisocyanato-l,l'-biphenyl; 1,6- diisocyanato-2,2,4-trimethylhexane; 3,3'-dimethoxy- 4,4'-biphenylene diisocyanate; 2,2-diisocyanatopropane; 1,3-diisocyanatopropane; 1,4- diisocyanatobutane; 1 ,5- diisocyanatopentane; 1 ,6-diisocyanatohexane; 2,3-diisocyanatotoluene; 2,4- diisocyanatotoluene; 2,5-diisocyanatotoluene; 2,6-diisocyanatotoluene; isophorone diisocyanate; hydrogenated methylene bis(phenylisocyanate); naphthalene- 1,5- diisocyanate; l-methoxyphenyl-2,4-diisocyanate;l,4-diisocyanatobutane; 4,4'- biphenylene diisocyanate; 3,3'-dimethyldiphenylmethane- 4,4'-diisocyanate; 4,4',4"- triphenylmethane triisocyanate; toluene-2,4,6-triisocyanate; 4,4'- dimethyldiphenylmethane-2 ,2' ,5 ,5 '-tetraisocyanate ; polymethylene polyp henylene polyisocyanate; or a mixture of any two or more thereof. In a preferred embodiment, the diisocyanate is 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, or a mixture of 2,4- and 2,6-toluene diisocyanate.

[0054] In certain embodiments, the isocyanate component for forming the polycarbodiimide comprises MDI (in any the three isomers (2,2'-MDI, 2,4'-MDI, and 4,4'-MDI). Alternatively, the isocyanate component may comprise a blend of two or all three of these three MDI isomers, i.e., the isocyanate component may comprise at least two of 2,2'-MDI, 2,4'-MDI, and 4,4'-MDI.

[0055] In certain other embodiments, the isocyanate component for forming the polycarbodiimide comprises toluene diisocyanate (TDI). The isocyanate component may comprise either isomer of toluene diisocyanate (TDI), i.e., the isocyanate component may comprise 2,4-toluene diisocyanate (2,4-TDI) or 2,6-toluene diisocyanate (2,6-TDI). Alternatively, the isocyanate component may comprise a blend of these isomers, i.e., the isocyanate component may comprise both 2,4-toluene diisocyanate (2,4-TDI) and 2,6-toluene diisocyanate (2,6-TDI). One specific example of a commercially available isocyanate component suitable for the purposes of the present invention is Lupranate® T-80, which is commercially available from BASF Corporation of Florham Park, New Jersey. Notably, Lupranate ^® T-80 comprises a blend of 2,4-toluene diisocyanate (2,4-TDI) and 2,6-toluene diisocyanate (2,6-TDI). In certain embodiments, the isocyanate component consists essentially of, or consists of, TDI. Generally, the isocyanate component comprises TDI in an amount of from greater than 95, alternatively greater than 96, alternatively greater than 97, alternatively greater than 98, alternatively greater than 99, percent by weight based on the total weight of isocyanate present in the isocyanate component.

[0056] In certain embodiments, the isocyanate component and the isocyanate- reactive component are reacted in the presence of a blowing agent to produce the overlay 50 as a polyurethane foam. More specifically, the isocyanate-containing compound reacts with the polyether polyol in the presence of the blowing agent to produce the polyurethane foam overlay 50.

[0057] As is known in the art, during the polyurethane foaming reaction between the isocyanate component and the isocyanate-reactive component, the blowing agent promotes the release of a blowing gas that forms cell voids in the polyurethane foam. The blowing agent may be a physical blowing agent, a chemical blowing agent, or a combination of a physical blowing agent and chemical blowing agent.

[0058] The terminology "physical blowing agent" refers to blowing agents that do not chemically react with the isocyanate component and/or the isocyanate-reactive component to provide the blowing gas. The physical blowing agent can be a gas or liquid. The liquid physical blowing agent typically evaporates into a gas when heated, and typically returns to a liquid when cooled. The physical blowing agent typically reduces the thermal conductivity of the polyurethane foam. Suitable physical blowing agents for the purposes of the subject invention may include liquid CO ₂ , acetone, methyl formate, hydro flu oroolefin (HFO), pentane, and combinations thereof. The most typical physical blowing agents typically have a zero ozone depletion potential.

[0059] The terminology "chemical blowing agent" refers to blowing agents that chemically react with the isocyanate component or with other components to release a gas for foaming. Examples of chemical blowing agents that are suitable for the purposes of the subject invention include formic acid, water, and combinations thereof.

[0060] The blowing agent is typically present in the isocyanate-reactive component in an amount of from about 0.5 to about 20 parts by weight based on 100 parts by weight of total polyol present in the isocyanate-reactive component. In certain embodiments, a combination of chemical and physical blowing agents is utilized, such as water and liquid CO ₂ .

[0061] One exemplary method of producing the polyurethane foam comprises the steps of providing the isocyanate component, providing the isocyanate-reactive component, and reacting the isocyanate component with the isocyanate-reactive component to produce the polyurethane foam as the overlay 50. The method may further comprise the steps of providing the catalyst component and reacting the isocyanate component with the isocyanate-reactive component in the presence of the catalyst component to produce the polyurethane foam.

[0062] The heat resistant insert 30 is selected of a material or composition that does not degrade at temperatures experienced by portions of the multi-component engine cover 20 during operation of the engine 15. In addition, the heat resistant insert 30 is selected from a material that is lightweight and capable of being coupled to or bonded to the overlay 50. Yet still further, the heat resistant insert 30 should be formed from a material or composition that is fire resistant.

[0063] In certain embodiments, the heat resistant insert 30 is a flexible, open-cell foam made from a melamine resin (i.e., a melamine foam). In even further embodiments, the melamine foam is formed from a formaldehyde-melamine-sodium bisulfite copolymer. One commercially available melamine foam comprising a formaldehyde-melamine-sodium bisulfite copolymer is sold by BASF of Florham Park, New Jersey under the tradename Basotect ^® , including but not limited to Basotect ^® G, TG, G+, UF, UL or Basotect ^® W. Basotect ^® foams for use in the presently invention have high temperature resistance of up to 240 degrees Celsius and have flame retardance rating of B 1 measured in accordance with the test standard DIN 4102.

[0064] The multi-component engine cover 20, formed from the heat resistant insert 30 and polyurethane overlay 30, in addition to providing the aesthetically pleasing outer surface 24 and heat resistant properties, also provides certain mechanical properties to the engine cover 20.

[0065] Accordingly, in certain embodiments, the tensile strength of the multi- component engine cover 20, as measured in accordance with ASTM D3574, is greater than or equal to 150 kPa. Accordingly, in certain embodiments, the tear strength of the multi-component engine cover 20, as measured in accordance with ASTM D3574, is greater than or equal to 350N/m. Accordingly, in certain embodiments, the elongation of the multi-component engine cover 20, as measured in accordance with ASTM D3574, is greater than or equal to 60%. In still further embodiments, the multi-component engine cover includes a combination of any two or all three of these mechanical properties.

[0066] Various methods may be used to form the multi-component engine covers of the present invention.

[0067] In one method, a mold 100 is used to form the multi-component engine cover 20. In these embodiments, as shown in Figures 5-7 the mold 100 includes an inner cavity 105 sized and shaped to correspond to the size and shape of the multi- component engine cover 20. The inner cavity 105 includes an inner cavity surface 110 and an outer cavity surface 115 shaped to correspond to the inner surface 22 and outer surface 24, respectively of the multi-component engine cover 20. The mold 100 also includes one or more ports 116, 117 fluidically linked to a separate port 118 through which the isocyanate reactive component 120 and isocyanate component 125 used to form the overlay 50 may be mixed and introduced onto the heat resistant insert 30, or multiple heat resistant inserts 30, 30A, 30B, 30C.

[0068] To form the cover 20, the heat resistant insert 30, or multiple heat resistant inserts 30, 30A, 30B, 30C, are inserted into the cavity 105 while the mold 100 is open such that the inner side surface 32 of each respective insert 30, 30A, 30B, 30C is adjacent to a respective subsection 112 of the inner cavity surface 110, as shown best in Figure 6. In certain embodiments, the insert 30, 30A, 30B, 30C is secured to the inner side surface 32 by pressing the respective insert onto one or more pins (not shown) extending into the open portion of the mold 100 at a pressure sufficient to seat the insert against the inner surface 32 surrounding the pins. Optionally, a mold release agent (such as a wax or the like) can be applied to the mold 100 prior to the insertion of the inserts 30, 30A, 30B, 30C. Still further, an in mold coating (IMC), typically a polyurethane-based coating may also optionally be applied to the mold 100 onto the dried mold release agent prior to the insertion of the inserts 30, 30A, 30B, 30C.

[0069] Next, as shown in Figure 7, the mold 100 is closed, and the isocyanate- reactive component 120 and isocyanate component 125 are introduced to the remaining portion 107 of the cavity 105 not occupied by the heat resistant insert 30. Preferably, the isocyanate-reactive component 120 and isocyanate component 125 are mixed and injected within the cavity 105 through the injector 119 of the port 118. The port 118, as noted above, is fluidically linked to each of the ports 116 and 117 storing the isocyanate-reactive component 120 and isocyanate component 125, respectively. Accordingly, the isocyanate reactive component 120 is introduced from the port 116 into the port 118, and the isocyanate component 125 is separately introduced from the port 117 into the port 118, wherein the isocyanate reactive component 120 and isocyanate component 125 are premixed in the desired ratios. The mixture of the isocyanate reactive component 120 and isocyanate component 125 are dispensed through the injector 119 within the remaining portion 107 of the mold 105.

[0070] In the remaining portion 107 of the cavity 105, the hydro xyl-groups of the isocyanate-reactive component 120 reacts with the isocyanate groups of the isocyanate component 120 under heat and pressure, therein forming carbamate (i.e., urethane) links. The completion of the reaction therein forms the polyurethane overlay 50 within the remaining portion 107 of the cavity 105. In embodiments wherein a foam overlay 50 is formed, a blowing agent (such as described above) is introduced in addition to the isocyanate-reactive component 120 and isocyanate component 125 within the closed mold 100, with the blowing agent creating cells within the formed polyurethane polymer of the overlay 50.

[0071] In certain embodiments, the inner side surface 32 of the heat resistant insert does not cover the entire inner cavity surface 110, and thus in these embodiments the formed overlay 50 extends along a portion of the inner cavity surface 110, as illustrated in the resultant engine cover 20 as shown in Figures 1-4 above.

[0072] Once the reaction of the isocyanate-reactive component and the isocyanate component is complete, and the overlay 50 is formed, the mold 100 is opened, and the multi-component engine cover 20 is removed from the mold 100 (not shown).

[0073] The subject application thus provides a solution for addressing the heat degradation issues associated with the use of a single component polyurethane engine cover to engines by positioning the heat resistant insert along portions of the heat resistant cover that receive temperatures during the operation of the engine that are greater than the heat degradation temperature of the polyurethane cover. The subject application provides a simple, single step forming process that is repeatable and efficient. Further, because the melamine foam is provided on an inner surface of the multi-component engine cover, the aesthetic exterior surface, which includes the overlay, is maintained.

[0074] The following example is intended to illustrate the invention and are not to be viewed in any way as limiting to the scope of the invention.

EXAMPLE

[0075] An engine cover is prepared using a polyurethane (PU) system and melamine foam. The PU system is prepared from Elastoflex® 28390R Resin and Elastoflex® 28390T isocyanate, both commercially available from BASF Corporation. The PU system also includes a polyether triol-based with an ethylene oxide cap and a styrene-acrylonitrile graft polyol. The weight ratio of the resin to the isocyanate in the PU systems is about 100:51.

[0076] The engine cover is prepared by a high-pressure metering machine using an aluminum mold with coolant lines for temperature control and water is used as the blowing agent.

[0077] Basotect® G+ is cut to size and then positioned in the mold before the PU system is added. The pieces of melamine foam are positioned as desired and may be held in place by pins or other fastening means which may be integrated into the mold. The engine cover is then prepared by dispensing the PU system into the mold via the high pressure metering machine and an open pour method under the following processing conditions: Day tank temperatures: 70 - 85 °F; Mold temperature: 120 - 140 °F; Demold time: 3 - 4 minutes; Mixing pressure: 1900 - 2200 psi. The mold is closed and the part is allowed to cure. [0078] Once the engine cover cured, the part is removed from the mold. It is then evaluated to determine is ability to perform as an engine cover.

[0079] The PU system used in the example above has been tested to evaluate its suitability for use in engine cover applications. The table below summarizes the results collected:

Table 1

[0080] It is to be understood that the appended claims are not limited to express and particular compounds, surface treatment materials, or methods described in the detailed description, which may vary between particular embodiments that fall within the scope of the appended claims. With respect to any Markush groups relied upon herein for describing particular features or aspects of various embodiments, different, special, and/or unexpected results may be obtained from each member of the respective Markush group independent from all other Markush members. Each member of a Markush group may be relied upon individually and or in combination and provides adequate support for specific embodiments within the scope of the appended claims.

[0081] Further, any ranges and subranges relied upon in describing various embodiments of the present invention independently and collectively fall within the scope of the appended claims, and are understood to describe and contemplate all ranges including whole and/or fractional values therein, even if such values are not expressly written herein. One of skill in the art readily recognizes that the enumerated ranges and subranges sufficiently describe and enable various embodiments of the present invention, and such ranges and subranges may be further delineated into relevant halves, thirds, quarters, fifths, and so on. As just one example, a range "of from 0.1 to 0.9" may be further delineated into a lower third, i.e., from 0.1 to 0.3, a middle third, i.e., from 0.4 to 0.6, and an upper third, i.e., from 0.7 to 0.9, which individually and collectively are within the scope of the appended claims, and may be relied upon individually and/or collectively and provide adequate support for specific embodiments within the scope of the appended claims. In addition, with respect to the language that defines or modifies a range, such as "at least," "greater than," "less than," "no more than," and the like, it is to be understood that such language includes subranges and/or an upper or lower limit. As another example, a range of "at least 10" inherently includes a subrange of from at least 10 to 35, a subrange of from at least 10 to 25, a subrange of from 25 to 35, and so on, and each subrange may be relied upon individually and/or collectively and provides adequate support for specific embodiments within the scope of the appended claims. Finally, an individual number within a disclosed range may be relied upon and provides adequate support for specific embodiments within the scope of the appended claims. For example, a range "of from 1 to 9" includes various individual integers, such as 3, as well as individual numbers including a decimal point (or fraction), such as 4.1, which may be relied upon and provide adequate support for specific embodiments within the scope of the appended claims. Still further, the term "about", when used in accordance with a number or numerical range, includes numbers or numerical ranges that are within 1 % above or below of the actual number provided. As an example, a temperature provided as "about 150 degrees" provides adequate support for temperatures ranging from as little as 148.5 degrees to as high as 151.5 degrees.

[0082] The invention has been described in an illustrative manner, and it is to be understood that the terminology that has been used is intended to be in the nature of words of description rather than of limitation. Obviously, many modifications and variations of the present invention are possible in light of the above teachings. The invention may be practiced otherwise than as specifically described.