Sandwich plate stable at high temperature

Abstract

The present invention provides a reaction mixture for use in the production of polyurethane / polyisocyanurate sandwich panels having high temperature stability of up to about 230 DEG C. The polyurethane / polyisocyanurate sandwich panel can be used for producing automobile components. The present invention also provides a method of producing a polyurethane / polyisocyanurate molded article exhibiting high temperature stability.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 340,210, filed on May 10, 2022, the entire contents of which are expressly incorporated herein by reference.

[0003] STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0004] not applicable. Technical Field

[0005] The present invention generally relates to reaction mixtures for producing polyurethane / polyisocyanurate sandwich panels, methods for producing polyurethane / polyisocyanurate sandwich panels, and structures including polyurethane / polyisocyanurate sandwich panels, which can be used in various applications, including but not limited to automotive applications. Background Art

[0006] Due to their light weight and hardness, sandwich panels based on polyurethane have been widely adopted to use in automotive applications. These sandwich panels generally include a core made of paper, thermoplastic or metal made of thermosetting or thermoplastic foam or honeycomb / cylindrical structure, which is positioned between two skins made of fiber-reinforced polymers. Fiber-reinforced material can adopt the form of glass, carbon, natural or polymer fiber mats in chopped, continuous, sewed or needle form. The reaction mixture forming polyurethane is applied to at least one side of the semi-finished sandwich panel, preferably applied by spraying. Then this semi-finished sandwich panel is put into a mold, and by compressing in a hot pressing method so that the polyurethane reaction mixture hardens, give a specific shape.

[0007] One drawback of current polyurethane-based sandwich panels is that they cannot withstand exposure to high temperatures and are therefore limited in production for use in automotive load floors. Specifically, when exposed to high temperatures, polyurethane-based sandwich panels can exhibit defects, as evidenced by irreversible bulging or surface blistering in resin-rich areas.

[0008] There is a need to improve current polyurethane-based sandwich panels so that they can be used in the production of other semi-structural automotive parts that are exposed to high temperatures, such as roof modules, hoods, side panels and liftgates. Summary of the invention

[0009] The present invention describes a reaction mixture for producing a polyurethane / polyisocyanurate sandwich panel exhibiting high temperature stability, the reaction mixture comprising: (i) a polyol; (ii) a polyisocyanate; (iii) a catalyst, (iv) a blowing agent; and optionally (v) at least one chain extender or crosslinker and optionally (vi) additives, and wherein the reaction mixture has an isocyanate index greater than 200.

[0010] Also provided is a method for producing a polyurethane / polyisocyanurate molded article exhibiting high temperature stability, comprising the steps of:

[0011] a) applying a first fiber material having a first surface and a second surface to the first surface of the core material;

[0012] b) applying a second fiber material having a first surface and a second surface to the second surface of the core material to form a sandwich structure having a first surface and a second surface, wherein the first fiber material and the second fiber material may be the same or different;

[0013] c) applying the reaction mixture of claim 1 to a first surface and a second surface of the sandwich structure to form a sandwich structure coated with the reaction mixture;

[0014] d) placing the sandwich structure coated with the reaction mixture in a mold;

[0015] e) forming the sandwich structure coated with the reaction mixture in a mold at a temperature in the range of about 100° C. to about 160° C., while curing the reaction mixture to form a polyurethane / polyisocyanurate molded article;

[0016] f) removing the polyurethane / polyisocyanurate molded article from the mold; and

[0017] e) Optionally, post-treating the polyurethane / polyisocyanurate molding. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1A is a diagrammatic representation of the method of the present invention;

[0019] Figure 1B yes Figure 1A an enlarged view of the sandwich structure of the illustrated method; and

[0020] Figure 1C yes Figure 1A Magnified view of a molded article of the illustrated process. DETAILED DESCRIPTION

[0021] The present invention provides a reaction mixture for producing polyurethane / polyisocyanurate sandwich panels that exhibit high temperature stability, the reaction mixture comprising: (i) a polyol; (ii) a polyisocyanate; (iii) a catalyst, (iv) a blowing agent; and optionally (v) at least one chain extender or crosslinker, and optionally (vi) an additive, and wherein the reaction mixture has an isocyanate index greater than 200. By making a series of changes to the reaction mixture used in the prior art for producing rigid foams, including changing the components of the reaction mixture and increasing the isocyanate index and optimizing the mold temperature, the polyurethane / polyisocyanurate sandwich panels can be molded within the current processing window and achieve high temperature stability (i.e., not exhibiting thermal and dimensional instability after prolonged exposure to temperatures up to about 210°C, or up to about 230°C) up to about 210°C, or in other embodiments up to about 230°C. Thus, such panels can now be effectively used in the production of various automotive components during in-line primary assembly of vehicles, including but not limited to roofs, hoods, door panels, liftgates, and floors.

[0022] If it appears in this article, the term "includes / comprising" and its derivatives are not intended to exclude the presence of any additional components, steps or procedures, whether or not disclosed in this article. For the avoidance of any doubt, all compositions claimed herein using the term "includes / comprising" may include any additional additives, adjuvants or compounds unless otherwise specified. In contrast, if it appears in this article, the term "essentially consisting of..." excludes any other components, steps or procedures from the scope of any subsequent description, except those that are not necessary for operability; and if used, the term "consisting of..." excludes any components, steps or procedures that are not specifically described or listed. Unless otherwise specified, the terms "or" and "and / or" refer to individual enumerated members and any combination thereof. For example, the expression A and / or B refers to only A, only B, or both A and B.

[0023] The article "a / an" is used herein to refer to one / one or more than one / more than one (i.e., at least one / one) grammatical object of the article. For example, "a polyol" means one polyol or more than one polyol. The expressions "in one embodiment", "according to one embodiment", etc. generally mean that the features, structures or characteristics following the expression are included in at least one embodiment of the present invention, and may be included in more than one embodiment of the present invention. Importantly, these expressions do not necessarily refer to the same embodiment. If the specification states that a component or feature "may", "can", "could" or "might" be included or have a certain characteristic, it is not required that the component or feature be included or have that characteristic.

[0024] The terms "preferred" and "preferably" refer to embodiments that may provide certain benefits in certain circumstances. However, other embodiments may also be preferred under the same or other circumstances. In addition, the description of one or more preferred embodiments does not imply that other embodiments are not applicable, and is not intended to exclude other embodiments from the scope of the present invention.

[0025] As used herein, the term "about" may allow a certain degree of variation in a value or range, for example, it may be within 10%, within 5%, or within 1% of a stated limit of a stated value or range.

[0026] Values ​​expressed in range format should be interpreted in a flexible manner to include not only the values ​​explicitly described as range limits, but also all individual values ​​or subranges encompassed within the range, as if each value and subrange were explicitly stated. For example, a range such as 1 to 6 should be considered to have explicitly disclosed subranges such as 1 to 3, 2 to 4, 3 to 6, etc., as well as individual values ​​within the range, such as 1, 2, 3, 4, 5, and 6. This applies regardless of the breadth of the range.

[0027] The term "optional" or "optionally" means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where said event or circumstance occurs and instances where it does not.

[0028] As used herein, the term "extended period of time" refers to any period of time that one skilled in the art would consider to be extended relative to the assembly of a structure (such as a vehicle) using the molded part, and specifically refers to a period of time such as at least about 5 minutes, or at least about 10 minutes, or at least about 15 minutes, or at least about 30 minutes.

[0029] "Isocyanate index" or "NCO index" or "index" refers to the ratio of NCO groups present in a formulation relative to isocyanate-reactive hydrogen atoms, given as a percentage: [NCO] x 100 / [active hydrogen] (%).

[0030] The term "hydroxyl value" refers to the concentration of hydroxyl groups that can react with -NCO groups per unit weight of polyol. The hydroxyl value is reported in mg KOH / g and can be measured according to standard ASTM D 1638.

[0031] The term "average functionality" or "average hydroxyl functionality" of a polyol refers to the average number of OH groups per molecule. The average functionality of an isocyanate refers to the average number of -NCO groups per molecule.

[0032] As used herein, the term "reaction mixture" may be used when two or more components of the mixture have been combined, or refers to all components of the mixture before they are combined, and does not necessarily require that all components be present at the same time at all times.

[0033] The term "substantially free" refers to a composition in which a particular component or moiety is present in an amount that does not have a substantial effect on the overall composition. In some embodiments, "substantially free" may refer to a composition in which a particular component or moiety is present in an amount of less than about 5% by weight, or less than about 4% by weight, or less than about 3% by weight, or less than about 2% by weight, or less than about 1% by weight, or less than about 0.5% by weight, or less than about 0.1% by weight, or less than about 0.05% by weight, or even less than about 0.01% by weight, based on the total weight of the composition, or a composition in which the particular component or moiety is not present in the corresponding composition.

[0034] Thus, the present invention provides a reaction mixture for producing a polyurethane / polyisocyanurate sandwich panel that exhibits high temperature stability up to about 210°C or in some embodiments up to about 230°C. In one embodiment, the reaction mixture includes (i) a polyol having at least two isocyanate-reactive moieties per compound. For example, the polyol or mixture thereof may be a liquid at 25°C, have a molecular weight of 60 to 10,000 Daltons (e.g., 300 to 10,000 Daltons or less than 5,000 Daltons), a nominal hydroxyl functionality of at least 2, and a hydroxyl equivalent weight of 30 to 2000 (e.g., 30 to 1500 or 30 to 800). Examples of polyols that may be used include polyether polyols such as those made by adding alkylene oxides to initiators having 2 to 8 active hydrogen atoms per compound. In some embodiments, the above-mentioned initiator includes glycol, glycerol, trimethylolpropane, triethanolamine, pentaerythritol, sorbitol, sucrose, ethylenediamine, ethanolamine, diethanolamine, aniline, toluenediamine (e.g., 2,4 toluenediamine and 2,6 toluenediamine), polymethylene polyphenylene polyamine, N-alkylphenylenediamine, o-chloroaniline, p-aminoaniline, diaminonaphthalene or a combination thereof. Suitable alkylene oxides that can be used to form polyether polyols include ethylene oxide, propylene oxide and butylene oxide or a combination thereof.

[0035] Other suitable polyols include Mannich polyols having a nominal hydroxyl functionality of at least 2 and having at least one secondary amine nitrogen atom or tertiary amine nitrogen atom per molecule. In some embodiments, Mannich polyols are condensates of aromatic compounds, aldehydes and alkanolamines. For example, Mannich condensates can be produced by the condensation of one or both of phenol and alkylphenol with formaldehyde and one or more of monoethanolamine, diethanolamine and diisopropanolamine. In some embodiments, Mannich condensates include the reaction product of phenol or nonylphenol with formaldehyde and diethanolamine. Mannich condensates can be manufactured by any known method. In some embodiments, Mannich condensates can be used as an initiator for alkoxylation. Any alkylene oxide (such as those mentioned above) can be used to alkoxylate one or more Mannich condensates. When polymerization is complete, Mannich polyols include primary hydroxyl and / or secondary hydroxyl groups bonded to aliphatic carbon atoms.

[0036] In certain embodiments, the polyol used is a polyether polyol containing propylene oxide ("PO"), ethylene oxide ("EO"), or a combination of PO and EO groups or moieties in the polymeric structure of the polyol. These PO units and EO units can be arranged randomly or in blocks throughout the polymer structure. In certain embodiments, the EO content of the polyol is 0 to 100 wt % based on the total weight of the polyol (e.g., 0 to about 50 wt %, or about 50 to 100 wt % based on the total weight of the polyol). In some embodiments, the PO content of the polyol is 100 to 0 wt % based on the total weight of the polyol (e.g., 100 to about 50 wt %, or about 50 to 0 wt % based on the total weight of the polyol). Therefore, in some embodiments, the EO content of the polyol may be about 99 to about 33 wt % of the polyol, while the PO content may be about 1 to 67 wt % of the polyol. In other embodiments, the PO content of the polyol may be about 99 to about 33 wt % of the polyol and the EO content may be about 1 to about 67 wt % of the polyol. In addition, in some embodiments, the EO and / or PO units may be located at the end of the polymer structure of the polyol or in the inner segment of the polymer backbone structure of the polyol. Suitable polyether polyols include poly(oxyethylene) diols and triols obtained by adding ethylene oxide to difunctional initiators or trifunctional initiators known in the art; poly(oxypropylene) diols and triols obtained by adding propylene oxide to difunctional initiators or trifunctional initiators known in the art, and poly(oxyethylene) and poly(oxypropylene) diols and triols obtained by sequentially adding propylene oxide and ethylene oxide to difunctional initiators or trifunctional initiators known in the art. In certain embodiments, the polyol comprises a single diol or triol as described above, or alternatively, the polyol comprises a mixture of these diols and triols.

[0037] The above-mentioned polyether polyols also include reaction products obtained by polymerization of ethylene oxide with another cyclic oxide (e.g., propylene oxide) in the presence of a multifunctional initiator such as water and a low molecular weight polyol. Suitable low molecular weight polyols include ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, cyclohexanedimethanol, resorcinol, bisphenol A, glycerol, trimethylolpropane, 1,2,6-hexanetriol, pentaerythritol, or a combination thereof.

[0038] In another embodiment, the polyol may include a polyester polyol. The polyester polyol includes a polyester having a linear polymer structure and a number average molecular weight of about 500 Daltons to about 10,000 Daltons (e.g., preferably about 700 Daltons to about 5,000 Daltons or about 700 Daltons to about 4,000 Daltons) and an acid value of generally less than 1.3 (e.g., less than 0.8). The molecular weight is determined by determining the terminal functional groups and is related to the number average molecular weight. The polyester polymer can be produced using techniques known in the art, such as: (1) esterification of one or more diols with one or more dicarboxylic acids or anhydrides; or (2) transesterification (i.e., the reaction of one or more diols with an ester of a dicarboxylic acid). It is generally preferred that the molar ratio of diol to acid is greater than 1 mole to obtain a linear polymer chain with terminal hydroxyl groups. Suitable polyester polyols also include various lactones generally made from caprolactone and a difunctional initiator such as diethylene glycol. The dicarboxylic acid of the desired polyester may be aliphatic, alicyclic, aromatic, or a combination thereof. Suitable dicarboxylic acids that can be used alone or with a mixture and generally have a total of 4 to 15 carbon atoms include succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid or a combination thereof. Acid anhydrides (e.g. phthalic anhydride, tetrahydrophthalic anhydride or a combination thereof) of the above-mentioned dicarboxylic acids can also be used. In some embodiments, adipic acid is a preferred acid. The glycols for forming suitable polyester polyols can include aliphatic glycols and aromatic glycols with a total of 2 to 12 carbon atoms. Examples of such diols include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, 1,5-pentanediol, 1,6-hexanediol, 2,2-dimethyl-1,3-propanediol, 1,4-cyclohexanedimethanol, decamethylene glycol, dodecamethylene glycol, or combinations thereof.

[0039] Other examples of suitable polyols include hydroxy-terminated polythioethers, polyamides, polyesteramides, polycarbonates, polyacetals, polyolefins and polysiloxanes. In some embodiments, the polyols may be combined with other isocyanate-reactive materials such as, but not limited to, polyamines or polythiols. Suitable polyamines include primary and secondary amine-terminated polyethers, aromatic diamines such as diethyltoluenediamine, aromatic polyamines and combinations thereof.

[0040] In one embodiment, the amount of polyol present in the reaction mixture is at least about 50% by weight, or at least about 60% by weight, or at least about 70% by weight, or at least about 80% by weight based on the total weight of the above-mentioned components (i), (iii), (iv), (v), and (vi). In other embodiments, the amount of polyol present in the reaction mixture is in the range of about 50% by weight to 95% by weight, or about 55% by weight to about 90% by weight, or about 60% by weight to about 85% by weight based on the total weight of the components (i), (iii), (iv), (v), and (vi). In still another embodiment, the amount of polyol present in the reaction mixture is less than 50% by weight, or less than about 45% by weight, or less than about 40% by weight based on the total weight of the above-mentioned components (i), (iii), (iv), (v), and (vi).

[0041] The reaction mixture further comprises (ii) a polyisocyanate. The polyisocyanate may be: (1) diphenylmethane diisocyanate comprising at least 40 wt %, preferably at least 50 wt % or at least 60 wt %, and most preferably at least 85 wt % of 4,4'-diphenylmethane diisocyanate (4,4'-MDI); (2) a carbodiimide and / or uretonimine modified variant of diphenylmethane diisocyanate (1) having an NCO value of 20 wt % or more; (3) a urethane modified variant of diphenylene diisocyanate (1) having an NCO value of 20 wt % or more; (4) a prepolymer having an NCO value of 20 wt % or more and being the reaction product of an excess of diphenylmethane diisocyanate (1) and a polyol having an average nominal hydroxyl functionality of 2 to 4 and an average molecular weight of up to 1000; (5) a prepolymer having an NCO value of 20 wt % or more and being the reaction product of an excess of any of the above polyisocyanates (1) to (3) and a polyol having an average nominal hydroxyl functionality of 2 to 6, an average molecular weight of 2000 to 12000 and preferably 15 to 60 mg KOH / g hydroxyl value, such as petroleum-based polyester polyols and polyether polyols, and in particular from polyoxyethylene polyoxypropylene polyols having an average nominal hydroxyl functionality of 2-4, an average molecular weight of 2500-8000, and a hydroxyl value of preferably 15-60 mg KOH / g, and preferably an oxyethylene content of 5-25 wt %, the oxyethylene preferably being located at the end of the polymer chain, or an oxyethylene content of 50-90 wt %, the oxyethylene preferably being randomly distributed on the polymer chain; (5) polymeric MDI (e.g., MDI containing 30% to 80% w / w of 4,4'-MDI, and the remainder of the MDI comprising MDI oligomers and MDI homologues); (6) 2,4-MDI; or (7) a mixture of any of the foregoing polyisocyanates. In some embodiments, polyisocyanates (1) and (2) and mixtures thereof may be preferred as polyisocyanates.

[0042] In other embodiments, the polyisocyanate can be toluene diisocyanate ("TDI") (e.g., 2,4TDI, 2,6TDI, or a combination thereof), hexamethylene diisocyanate ("HMDI" or "HDI"), isophorone diisocyanate ("IPDI"), butylene diisocyanate, trimethylhexamethylene diisocyanate, di(isocyanatocyclohexyl)methane (e.g., 4,4'-diisocyanatodicyclohexylmethane), isocyanatomethyl-1,8-octane diisocyanate, tetramethylxylene diisocyanate ("TMXDI"), 1,5-naphthalene diisocyanate ("NDP"), p-phenylene diisocyanate ("PPDI"), 1,4-cyclohexane diisocyanate ("GDI"), tolidine diisocyanate ("TODI"), or a combination thereof.

[0043] The mixture of polyisocyanates can be produced according to any technique known in the art. If desired, the isomer content of diphenylmethane diisocyanate can be brought within a desired range by techniques well known in the art. For example, one technique to alter the isomer content is to add monomeric MDI (e.g., 2,4-MDI) to an MDI mixture containing more than the desired amount of polymeric MDI.

[0044] The reaction mixture also includes (iii) a catalyst. According to one embodiment, the catalyst includes a trimerization catalyst. Examples of trimerization catalysts include, but are not limited to, tris(dialkylaminoalkyl)-s-hexahydrotriazine, such as 1,3,5-tris(N,N-dimethylaminopropyl)-s-hexahydrotriazine, potassium salts of carboxylic acids (e.g., potassium acetate, potassium pivalate, potassium octanoate, potassium triethyl acetate, potassium neoheptanoate, potassium neooctanoate, potassium ethylhexanoate), tetraalkylammonium hydroxides, such as tetramethylammonium hydroxide, alkali metal hydroxides such as sodium hydroxide, alkali metal alkoxides, such as sodium methoxide and potassium isopropoxide, alkali metal salts of long-chain fatty acids with 10 to 20 carbon atoms and with side hydroxyl groups in some embodiments, quaternary ammonium carboxylates (e.g., (2-hydroxypropyl)trimethylammonium 2-ethylhexanoate ("TMR"), (2-hydroxypropyl)trimethylammonium formate ("TMR-2"), tetramethylammonium pivalate, tetramethyltriethylammonium acetate) and combinations thereof.

[0045] The trimerization catalyst may also include a trimerization catalyst compound selected from one or more organic metal salts, preferably alkali metal salts or alkaline earth metal salts, and one or more compounds selected from the following: a compound containing a formamide group having the structure -CO-NH2 and / or a compound containing a group having the structure -CO-NH-CO-, which is described in paragraphs

[0039] to

[0052] of EP2830761B1, the contents of which are incorporated herein by reference.

[0046] The amount of trimerization catalyst present in the reaction mixture may range from about 0.01-5 wt % based on the weight of (i) the polyol and (ii) the polyisocyanate, or in some embodiments, from about 0.05-3 wt % based on the combined weight of (i) the polyol and (ii) the polyisocyanate.

[0047] The catalyst may also include an amine catalyst compound containing at least one tertiary amine group, a non-amine catalyst compound, or a mixture thereof.

[0048] Examples of amine catalyst compounds containing at least one tertiary amine group include, but are not limited to, bis-(2-dimethylaminoethyl) ether (e.g., JEFFCAT® ZF-20 catalyst), N,N,N′-trimethyl-N′-hydroxyethyl bisaminoethyl ether (e.g., JEFFCAT® ZF-10 catalyst), N-(3-dimethylaminopropyl)-N,N-diisopropanolamine (e.g., JEFFCAT® DPA catalyst), N,N-dimethylethanolamine (e.g., JEFFCAT® DMEA catalyst), a blend of N,N-dimethylethanolamine and ethylenediamine (e.g., JEFFCAT® TD-20 catalyst), N,N-dimethylcyclohexylamine (e.g., JEFFCAT® DMCHA catalyst), N-methyldicyclohexylamine (e.g., POLYCAT® 12 catalyst), benzyldimethylamine (e.g., JEFFCAT® BDMA catalyst), diethyltoluenediamine, pentamethyldiethylenetriamine (e.g., JEFFCAT® PMDETA catalyst), N,N,N′,N″,N″-pentamethyldipropylenetriamine (e.g. JEFFCAT® ZR-40 catalyst), N,N-bis(3-dimethylaminopropyl)-N-isopropanolamine (e.g. JEFFCAT® ZR-50 catalyst), N′-(3-(dimethylamino)propyl-N,N-dimethyl-1,3-propanediamine (e.g. JEFFCAT® Z-130 catalyst), 2-(2-dimethylaminoethoxy)ethanol (e.g. JEFFCAT® ZR-70 catalyst), N,N,N′-trimethylaminoethylethanolamine (e.g. JEFFCAT® Z-110 catalyst), N-ethylmorpholine (e.g. JEFFCAT® NEM catalyst), N-methylmorpholine (e.g. JEFFCAT® NMM catalyst), 4-methoxyethylmorpholine, N,N′-dimethylpiperazine (e.g. JEFFCAT® DMP catalyst), 2,2′ dimorpholino diethyl ether (e.g. JEFFCAT® DMDEE catalyst), 1,3,5-tris(3-(dimethylamino)propyl)-hexahydro-s-triazine (e.g. JEFFCAT® TR-90 catalyst), 1-propylamine, 3-(2-(dimethylamino)ethoxy), substituted imidazoles (e.g. 1-methylimidazole, 1,2-dimethylimidazole) (e.g. DABCO® 2040 catalyst and TOYOCAT® DM70 catalyst), 1-methyl-2-hydroxyethylimidazole, N-(3-aminopropyl)imidazole, 1-n-butyl-2-methylimidazole, 1-isobutyl-2-methylimidazole, N,N′-dimethylpiperazine, disubstituted piperazines (e.g. aminoethylpiperazine, N,N′,N′-trimethylaminoethylpiperazine or bis-(N-methylpiperazine)urea), N-methylpyrrolidine and substituted methylpyrrolidines (e.g. 2-aminoethyl-N-methylpyrrolidine or bis-(N-methylpyrrolidine)ethylurea), 3-dimethylaminopropylamine, N,N,N″,N″-tetramethyldipropylenetriamine, tetramethylguanidine and 1,2-bis-diisopropanol. Other examples of amine catalysts include N-butylmorpholine, dimorpholinyl diethyl ether, N,N′-dimethylaminoethanol, N,N-dimethylaminoethoxyethanol, bis-(dimethylaminopropyl)-amino-2-propanol, bis-(dimethylamino)-2-propanol, bis-(N,N-dimethylamino)ethyl ether, N,N,N′-trimethyl-N′hydroxyethyl-bis-(aminoethyl) ether, N,N-dimethylaminoethyl-N-methylaminoethanol, tetramethyliminobispropylamine, N,N-dimethyl-p-toluidine, diethyltoluenediamine, 3,5-dimethylthio-2,4-toluenediamine; poly(oxypropylene)triamine (JEFFAMINE® T-5000 amine), reactive acid blocking catalysts (such as 1,8-diazabicyclo (5,4,0) undecene-7 phenolate) and combinations thereof.

[0049] The non-amine catalyst compound includes an organic metal compound (e.g., an organic salt of a transition metal such as titanium, iron, nickel), a post-transition metal (e.g., zinc, tin, and bismuth), an alkali metal (e.g., lithium, sodium, and potassium), an alkaline earth metal (e.g., magnesium and calcium), or a combination thereof. Other suitable non-amine catalyst compounds include ferric chloride, ferric acetylacetonate, zinc salts of carboxylic acids, zinc 2-ethylhexanoate, stannous chloride, stannic chloride, tin salts of carboxylic acids, dialkyltin salts of carboxylic acids, tin (II) 2-ethylhexanoate, dibutyltin dilaurate, dimethyltin dithiolate, bismuth (III) carboxylate salts (e.g., bismuth (2-ethylhexanoate)), bismuth neodecanoate, bismuth neopentanoate, bismuth-based catalysts, 1,1',1",1'"-(1,2-ethanediyldinitro)tetrakis[2-propanol]neodecanoate complex, 2,2',2",2'"-(1,2-ethanediyldinitro)tetrakis[ethanol]neodecanoate complex, K-KAT XC-C 227 Bismuth salts (available from King Industries), sodium acetate, sodium N-(2-hydroxy-5-nonylphenol)methyl-N-methylglycinate (JEFFCAT® TR52), bismuth (2-ethylhexanoate), and combinations thereof.

[0050] The amount of amine catalyst compound and non-amine catalyst compound present in the reaction mixture may range from about 0.01-4 wt %, or about 0.2-3.7 wt %, or about 0.5-3.5 wt %, based on the total weight of (i) polyol and (ii) polyisocyanate.

[0051] The reaction mixture also includes (iv) a blowing agent. In one embodiment, the blowing agent includes water. For the purposes of the present invention, water should be considered a component different from component (i). In other words, the reaction mixture disclosed herein not only includes component (i), but also includes water.

[0052] Any type of water may be used, including purified water that has been filtered or treated to remove impurities. Other suitable types of water include distilled water and water that has been purified by one or more of the following methods: capacitive deionization, reverse osmosis, carbon filtration, microfiltration, ultrafiltration, ultraviolet oxidation, and / or electrodeionization.

[0053] The amount of blowing agent present in the reaction mixture may be about 0.1-2.5 wt % or about 0.2-1.5 wt % based on the total weight of (i) polyol.

[0054] The reaction mixture may also optionally include (v) at least one chain extender or cross-linker. Chain extenders are generally grouped as having a functionality equal to 2, and include diols, diamines, and combinations thereof. The chain extender may have a molecular weight of up to about 500 Daltons or up to about 300 Daltons, such as at least about 35-500 Daltons.

[0055] One or more short-chain polyols having 2 to 20, or 2 to 12, or 2 to 10, or 2 to 8 carbon atoms can be used as chain extenders in the reaction system to increase the molecular weight of the thermoplastic polyurethane. Examples of chain extenders include, but are not limited to, low-level aliphatic polyols and short-chain aromatic diols having a molecular weight of less than 500 Daltons or less than 300 Daltons. Suitable chain extenders include organic diols (including glycols) having a total of 2 to about 20 carbon atoms, such as alkane diols, alicyclic diols, alkylaryl diols, and the like. Exemplary alkane diols include ethylene glycol, diethylene glycol, 1,3-propylene glycol, 1,3-butanediol, 1,4-butanediol, (BDO), 1,5-pentanediol, 2,2-dimethyl-1,3-propanediol, propylene glycol, dipropylene glycol, 1,6-hexanediol, 1,7-heptanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, tripropylene glycol, triethylene glycol, and 3-methyl-1,5-pentanediol. Examples of suitable cycloaliphatic diols include 1,2-cyclopentanediol and 1,4-cyclohexanedimethanol (CHDM). Examples of suitable aryl diols and alkylaryl diols include hydroquinone bis(1,3-hydroxyethyl) ether (HQEE), 1,2-dihydroxybenzene, 1,3-dihydroxybenzene, 1,4-dihydroxybenzene, 1,2,3-trihydroxybenzene, 1,2-bis(hydroxymethyl)benzene, 1,4-bis(hydroxymethyl)benzene, 1,3-bis(2-hydroxyethyl)benzene, 1,2-bis(2-hydroxyethoxy)benzene, 1,4-bis-(2-hydroxyethoxy)benzene, bisethoxybisphenol, 2,2-bis(4-hydroxyphenyl)propane (i.e., bisphenol A), bisphenol A ethoxylate, bisphenol F ethoxylate, 4,4-isopropylidene diphenol, 2,2-bis[4-(2-hydroxyethoxy)phenyl]propane (HEPP), and mixtures thereof. In another embodiment, the chain extender is a sucrose-based polyol such as sorbitol.

[0056] In another embodiment, the chain extender comprises a compound having the general formula (HO) x Q(COOH) y A hydroxycarboxylic acid wherein Q is a straight or branched hydrocarbon group containing 1 to 12 carbon atoms, and x and y are each an integer from 1 to 3. In certain embodiments, the chain extender comprises a diol carboxylic acid. In other embodiments, the chain extender comprises a bis(hydroxyalkyl)alkanoic acid. In certain embodiments, the chain extender comprises a bis(hydroxymethyl)alkanoic acid. In certain embodiments, the diol carboxylic acid is selected from 2,2-bis-(hydroxymethyl)-propionic acid (dimethylolpropionic acid, DMPA), 2,2-bis(hydroxymethyl)butanoic acid (dimethylolbutanoic acid; DMBA), dihydroxysuccinic acid (tartaric acid) and 4,4'-bis(hydroxyphenyl)valeric acid. In certain embodiments, the chain extender comprises N,N-bis(2-hydroxyalkyl)carboxylic acid.

[0057] Crosslinkers are generally grouped as having a functionality equal to or greater than 3. They are also generally represented by relatively short chain or low molecular weight molecules such as glycerol, ethanolamine, diethanolamine, trimethylolpropane (TMP), 1,2,6-hexanetriol, triethanolamine, pentaerythritol, N,N,N',N'-tetrakis(2-hydroxypropyl)-ethylenediamine, diethyl-toluenediamine, dimethylthiotoluenediamine, and combinations thereof.

[0058] In one embodiment, the amount of (v) chain extender or cross-linker or mixture thereof present in the reaction mixture may be about 0.1-15 wt % based on the total weight of (i) polyol. In another embodiment, the amount of chain extender or cross-linker or mixture thereof present in the reaction mixture may be about 0.5-12 wt % or about 1-10 wt % based on the total weight of (i) polyol.

[0059] The reaction system may also optionally include (vi) one or more known additives, including but not limited to surfactants, silane adhesion promoters, antioxidants, waxes, colorants, flame retardants, microbial inhibitors, fillers, mold release agents, viscosity reducers; carbon black, titanium dioxide and metal flake infrared opacifiers, inert and insoluble fluorinated compounds, and perfluorinated cell size reducing compounds, calcium carbonate fillers, glass fibers and / or ground foam waste reinforcements; zinc stearate, butylated hydroxytoluene antioxidants, dyes and pigments.

[0060] In certain embodiments, the surfactant may include one or more silicone-based or non-silicone-based surfactants. Suitable silicone surfactants that may be disclosed herein include polyorganosiloxane polyether copolymers and polysiloxane polyoxyalkylene block copolymers.

[0061] Non-silicone surfactants useful in the polyurethane insulation foam compositions disclosed herein include nonionic, anionic, cationic, amphoteric, semi-polar, zwitterionic organic surfactants. Suitable nonionic surfactants include phenol alkoxylates and alkylphenol alkoxylates (e.g., ethoxylated phenol and ethoxylated nonylphenol, respectively).

[0062] When present, these additional additives can be used in an amount of about 0.01-15 wt %, or about 0.1-10 wt %, or about 0.5-5 wt %, based on the total weight of the reaction mixture. These ranges can apply to each additional additive present in the reaction mixture or the total amount of all additional additives present, respectively.

[0063] In some embodiments, the reaction mixture may have a hydroxyl value of about 150-700 mg KOH / g, or about 200-600 mg KOH / g, or about 350-500 mg KOH / g. In another embodiment, the reaction mixture may have an isocyanate index greater than about 201, or greater than about 203, or greater than about 205, or greater than about 207, or greater than about 210. In other embodiments, the reaction mixture may have an isocyanate index less than about 10,000, or less than about 1,000, or less than about 500. In still other embodiments, the reaction mixture may have an isocyanate index greater than about 200 and less than about 500, or in the range of about 201-350.

[0064] According to another embodiment, there is provided a method for producing a polyurethane / polyisocyanurate molded article, comprising the steps of:

[0065] a) applying a first fiber material having a first surface and a second surface to the first surface of the core material;

[0066] b) applying a second fiber material having a first surface and a second surface to the second surface of the core material to form a sandwich structure having a first surface and a second surface, wherein the first fiber material and the second fiber material may be the same or different;

[0067] c) applying the reaction mixture of the present invention to the first surface and the second surface of the sandwich structure to form a sandwich structure coated with the reaction mixture;

[0068] d) placing the sandwich structure coated with the reaction mixture in a mold;

[0069] e) forming the sandwich structure coated with the reaction mixture in a mold at a temperature of about 100° C. to about 200° C., while curing the reaction mixture to form a polyurethane / polyisocyanurate molded article;

[0070] f) removing the polyurethane / polyisocyanurate molded article from the mold; and

[0071] e) optionally, post-treating the polyurethane / polyisocyanurate molding.

[0072] According to step a) and b), the first fiber material and the second fiber material are applied to the first surface and the second surface of the core material to form a sandwich structure with the first surface and the second surface. The first fiber material and the second fiber material may be identical or different, and may include woven fiber mats, nonwoven fiber mats, continuous strand fibers, fiber random structures, fiber tissues, chopped fibers, ground fibers, braids, reinforcing fiber mats or any combination thereof. Preferred fibers are carbon fibers, polymer fibers such as KEVLAR™ fiber or aramid fibers, mineral fibers, glass fibers, natural fibers such as kenaf, hemp, coconut and mixtures thereof. In one embodiment, the fiber material is glass fiber mats, glass fiber nonwovens, randomly laid glass fibers, woven glass fiber fabrics or chopped glass or frosted glass.

[0073] The core material may include honeycomb paperboard, plastic honeycomb, aluminum honeycomb, balsa wood, rigid foam, compressed or uncompressed cotton fibers, compressed or uncompressed natural fibers, or compressed or uncompressed plastic fibers such as polyethylene terephthalate (PET).

[0074] Then, in steps c) and d), the reaction mixture is applied to the first and second surfaces of the sandwich structure to form a sandwich structure coated with the reaction mixture, and then placed in a mold. While applying the reaction mixture, chopped fibers may optionally be applied to all or part of one or both surfaces of the sandwich structure. For example, when a reinforcing fiber mat is used in steps a) and / or b), the mat may be first removed and impregnated with the reaction mixture in a conventional manner, and then one or more types of chopped fibers may be additionally applied to all or part of one or more surfaces simultaneously. These additionally applied chopped fibers wetted by the reaction mixture are bonded. Applying the reaction mixture to the fiber material may be carried out by conventional methods, such as spraying, blade coating or roller coating. Application may be carried out, for example, at a temperature of 20°C to 50°C, preferably at an elevated temperature of 23°C to 45°C. The amount applied may vary within a certain range, such as within the following range: 150g / m 2 Up to 5000g / m 2 , particularly preferably 200g / m 2 Up to 2000g / m 2 , more preferably 400g / m 2 Up to 1000g / m 2 And especially 425g / m 2 Up to 500g / m 2This produces a reaction mixture coated sandwich structure having a core material and two fiber materials comprising the reaction mixture, which is then placed in a mold.

[0075] The sandwich structure coated with the reaction mixture is then formed and cured in a mold. The mold temperature may be in the range of about 0-180° C. or about 100-160° C. or about 130-150° C. The core material and the fiber material may optionally be pressed together with one or more outer or decorative layers. In this case, the outer or decorative layers may be applied to one or both sides of the sandwich structure coated with the reaction mixture, or they may be placed in the mold. As an alternative, the outer or decorative layers may be applied in a further working step after the polyurethane / polyisocyanurate molded article has been demoulded.

[0076] In this respect, the decorative material may be a carpet, a fabric impregnated with barrier polyurethane, a dense or foamed plastic film, and a spray-on skin or RIM skin of polyurethane. As outer layers, preformed materials suitable for exterior applications may also be used, such as metal foils or sheets (e.g. aluminum or steel), and dense thermoplastic composites of PMMA (polymethyl methacrylate), ASA (acrylate-modified styrene-acrylonitrile terpolymer), PC (polycarbonate), PA (polyamide), PBT (polybutylene terephthalate) and / or PPO (polyphenylene oxide) in painted, paintable or colored form, glass-reinforced composite sheets (e.g. sheet molding compounds, polyurethanes), in-mold coatings and combinations thereof. As outer layers, continuously or batch-produced outer layers based on melamine-phenol, phenol-formaldehyde, epoxy resins or unsaturated polyester resins may likewise be used.

[0077] During the pressing, the core material is compressed at least in the region of the core material. Compression can vary in a wide range, and can vary in a compression range of tens of millimeters to 10% less than the initial thickness of the core material. When the reaction mixture sandwich structure is pressed, the core material different regions are preferably compressed to different degrees. Alternatively, the reaction mixture can be applied to one or both sides of the first fiber material or the second fiber material or both. Subsequently, the fiber material comprising the reaction mixture is applied to the core material.

[0078] In an alternative embodiment to the above embodiment, there is provided a method for producing a polyurethane / polyisocyanurate molded article comprising the steps of:

[0079] a) placing a substrate such as a fabric or carpet in a mold,

[0080] b) applying the reaction mixture of the present invention to the surface of a substrate;

[0081] c) applying a first fiber material having a first surface and a second surface to the first surface of the core material;

[0082] d) applying a second fiber material having a first surface and a second surface to the second surface of the core material to form a sandwich structure having a first surface and a second surface, wherein the first fiber material and the second fiber material may be the same or different;

[0083] e) placing the sandwich structure in a mold such that a first surface of the sandwich structure is adjacent to the reaction mixture;

[0084] f) applying the reaction mixture of the present invention to the second surface of the sandwich structure by spraying to form a sandwich structure coated with the reaction mixture;

[0085] g) forming the sandwich structure coated with the reaction mixture in a mold at a temperature of about 100° C. to about 200° C., while curing the reaction mixture to form a polyurethane / polyisocyanurate molded article;

[0086] f) removing the polyurethane / polyisocyanurate molded article from the mold; and

[0087] e) Optionally, post-treating the polyurethane / polyisocyanurate molding.

[0088] In some embodiments, the sandwich structure may be preformed, and therefore steps c) and d) may be eliminated, and steps e) and f) may be replaced by:

[0089] e) placing the preformed sandwich structure in a mold such that a first surface of the preformed sandwich structure is adjacent to the reaction mixture;

[0090] f) applying the reaction mixture of the present invention to the second surface of the preformed sandwich structure by spraying to form a sandwich structure coated with the reaction mixture;

[0091] In some embodiments, the substrate can also be a metal foil, a metal sheet, polymethyl methacrylate in a painted, paintable or pigmented form, an acrylate-modified styrene acrylonitrile terpolymer, a thermoplastic composite of polycarbonate, polyamide, polybutylene terephthalate and / or polyphenylene ether, a glass-reinforced composite sheet, an in-mold coating, and combinations thereof.

[0092] Reference now Figures 1A-1C, the method of the present invention comprises the steps of: first applying a first fiber material 10 having a first surface 11 and a second surface 12 to a first surface 31 of a core material 30. Simultaneously or sequentially, applying a second fiber material 20 having a first surface 21 and a second surface 22 to a second surface 32 of the core material 30 to form a sandwich structure 40 having a first surface 41 and a second surface 42, wherein the first fiber material 10 and the second fiber material 20 may be the same or different. A low-pressure or high-pressure dispenser 50 may be used to spray the reaction mixture of the present invention from a mixing head 53. The mixing head 53 is fed from an A-side tank 51 containing a polyisocyanate and a B-side tank 52 containing a polyol. Components (iii), (iv), (v) and (vi) of the reaction mixture may be contained separately in an A-side tank or a B-side tank. The contents of the A-side tank and the B-side tank are mixed in the mixing head 53 and sprayed to each side 41 and 42 of the sandwich structure 40 through a nozzle 54. The reaction mixture from the mixing head 53 may be sprayed in a vertical position ( Figures 1A-1C ) or preferably in a horizontal position (such as Figure 1A 40. The reaction mixture 55 is applied to the first surface 41 and the second surface 42 of the sandwich structure 40. The (clamped) sandwich structure is preferably movable in the X and Y directions (length and width) below the dispensing machine, preferably by robotic movement, so that an even distribution of coating can be applied to the entire surface of the sandwich structure 40. The sandwich structure 40 is preferably rotated, preferably clamped, and rotated by robotic rotation so that each side 41 and 42 can be sprayed 55.

[0093] The sandwich structure 40 is then coated with the reaction mixture and placed in a mold 60 having a mold cavity defined by an upper mold half 61 and a lower mold half 62, (or alternatively, the sandwich structure 40 is placed in the mold 60 and coated with the reaction mixture), which is capable of forming the reaction mixture coated sandwich structure 40 into the desired molded article shape. Preferably, the mold 60 is temperature controlled. The mold is closed 70, and the reaction mixture coated sandwich structure is formed during the molding and curing steps 80. Preferably, the mold temperature is in the range of about 100°C to about 160°C or about 130°C to about 150°C. When the mold is closed and when molding is occurring / has occurred, the reaction mixture is cured 80 to form a molded polyurethane / polyisocyanurate coated sandwich structure or a molded polyurethane article 100. The mold 60 is opened, and the molded polyurethane article 100 is removed 90 from the mold 50. Optionally, the molded polyurethane article can be post-treated by one or more treatments, for example, a carpet can be applied, it can be painted, a decorative skin can be applied, it can be trimmed into a desired shape, etc. In some embodiments, one or more outer layers or decorative materials can be applied to the reactant mixture coated sandwich structure before the mold 60 is closed and the reactant mixture is cured.

[0094] In one embodiment, mold 60 is designed so that when the reactant coated sandwich structure is formed, part or all of the periphery of the final molded article is formed so that the inner core material is not visible or exposed. In other words, the cured polyurethane / polyisocyanurate coated fiber surfaces 101 and 102 cover or hide the core material and / or contact each other 103, such as Figure 1B shown.

[0095] The polyurethane / polyisocyanurate sandwich panels produced by the process according to the invention can be used, for example, as structural components or decorative parts, in particular in the automotive industry, the furniture industry or the construction industry.

[0096] The molded articles produced according to the invention can be used as components or lining / cladding parts, in particular for the automotive industry, for example load floors, lower sound insulation, sound insulation chassis panels, fairing covers, splash shields, underbody panels, chassis covers, door modules, rear compartment kits, leaf springs, roofs or engine hoods, for the furniture industry and the building and construction industry, such as door or window frames and curtain walls.

[0097] The following examples are provided to illustrate the invention but are not intended to limit its scope. Example

[0098] Honeycomb sandwich panels produced using various reaction mixtures

[0099] The honeycomb core (6 mm cell size) is covered on both sides with 450 g / m 2 The random chopped glass mat was prepared by mixing the reaction mixture shown in Table 1 at 450 g / m 2 Spray the original sandwich structure and then coat it with 450g / m 2 The perimeter spray coating was performed. The coated sandwich structure was then placed in the mold for 60 seconds, cured and demoulded. Each mold part was then exposed to a temperature close to 210°C for a minimum of 30 minutes, and the molded parts were inspected to determine if there were any defects on the molded parts.

[0100] Table 1

[0101] Polyol 1-PO based polyol, hydroxyl value 650

[0102] Polyol 2-PO based polyol, hydroxyl value 240

[0103] Crosslinker-Glycerol

[0104] Catalyst 1-Diethyltoluenediamine

[0105] Catalyst 2 - Acid blocked tertiary amine

[0106] Catalyst 3-Potassium octanoate in diethylene glycol

[0107] Comparative Example 1 was a comparative reaction mixture formulated to have an index of 205, and molded parts were produced using the reaction mixture at mold temperatures of 130° C., 140° C., and 150° C. After the molded parts were exposed to a temperature of 210° C. for the above period of time, severe blistering and defects were evident on the surface of each of them.

[0108] Example 1 and Example 2 are extensions of Comparative Example 1 and are formulated to have increased indices of 255 and 305, respectively. Defects were still evident on the Example 1 and Example 2 parts molded at a mold temperature of 130° C. and then exposed to a temperature of 210° C. However, when the mold temperature was increased to 140° C. and 150° C., no defects were found on the molded parts after exposure to a temperature of 210° C.

[0109] Examples 3-5 reflect the changes in formulations by introducing a crosslinker while maintaining the same hydroxyl value on the B side. For Example 3, defects were observed on parts molded at mold temperatures of 130°C and 140°C after exposure to a temperature of 210°C, but no defects were observed on parts molded at a mold temperature of 150°C after exposure to a temperature of 210°C. Similar results were observed for Example 4. Surprisingly, no defects were observed on Example 5 parts molded at mold temperatures of 130°C, 140°C, or 150°C after exposure to a temperature of 210°C. Note that the molecular weight (Mc) between crosslinks and the glass transition temperature onset by DMA G' are similar for both B-side variations (Comparative Example 1 / Example 1 / Example 2 vs. Example 3 / Example 4 / Example 5), which may indicate that the crosslinker plays a role in improving thermal stability beyond the crosslink density.

[0110] In Example 6, the A-side isocyanate was changed from a 4,4'-MDI based prepolymer to a uretonimine modified 4,4'-diphenylmethane diisocyanate. Parts molded at a temperature of 140°C did not show any defects after exposure to a temperature of 210°C.

[0111] Table 2

[0112] While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope of the invention is determined by the claims that follow.

Claims

1. A reaction mixture for producing a polyurethane / polyisocyanurate sandwich panel exhibiting high temperature stability, the reaction mixture comprising: (i) a polyol, (ii) a polyisocyanate, (iii) a catalyst, (iv) a blowing agent, and optionally (v) at least one chain extender or crosslinker, and optionally (vi) additives, and wherein the reaction mixture has an isocyanate index greater than 200.

2. The reaction mixture of claim 1, wherein the polyol comprises a polyether polyol.

3. The reaction mixture according to claim 2, wherein the polyether polyol is a poly(oxypropylene) diol or triol obtained by adding propylene oxide to a difunctional initiator or a trifunctional initiator.

4. The reaction mixture of claim 1, wherein the polyisocyanate is selected from (1) diphenylmethane diisocyanate comprising at least 40 wt % of 4,4'-diphenylmethane diisocyanate (4,4'-MDI), based on the total weight of the diphenylmethane diisocyanate; (2) carbodiimide and / or uretonimine modified variants of diphenylmethane diisocyanate (1) having an NCO value of 20 wt % or greater; and (3) mixtures thereof.

5. The reaction mixture of claim 1, wherein the catalyst comprises a trimerization catalyst.

6. The reaction mixture of claim 1, wherein the chain extender or crosslinker comprises ethylene glycol, diethylene glycol, 1,3-propylene glycol, 1,3-butanediol, 1,4-butanediol, (BDO), 1,5-pentanediol, 2,2-dimethyl-1,3-propanediol, propylene glycol, dipropylene glycol, 1,6-hexanediol, 1,7-heptanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, tripropylene glycol, triethylene glycol or 3-methyl-1,5-pentanediol, glycerol, sorbitol or mixtures thereof.

7. The reaction mixture of claim 1, wherein the one or more additives comprises a surfactant.

8. A method for producing a polyurethane / polyisocyanurate molded article exhibiting high temperature stability, comprising the steps of: a) applying a first fiber material having a first surface and a second surface to the first surface of the core material; b) applying a second fiber material having a first surface and a second surface to the second surface of the core material to form a sandwich structure having a first surface and a second surface, wherein the first fiber material and the second fiber material may be the same or different; c) applying the reaction mixture of claim 1 to the first surface and the second surface of the sandwich structure to form a reaction mixture coated sandwich structure; d) placing the sandwich structure coated with the reaction mixture in a mold; e) forming the sandwich structure coated with the reaction mixture in the mold at a temperature in the range of about 100° C. to about 160° C., while curing the reaction mixture to form the polyurethane / polyisocyanurate molded article; f) removing the polyurethane / polyisocyanurate molded article from the mold; and e) optionally, post-treating the polyurethane / polyisocyanurate molding.

9. The method of claim 8, wherein e) forming the sandwich structure coated with the reaction mixture in the mold is performed at a temperature in the range of about 130°C to about 150°C.

10. The method of claim 8, wherein the first and second fiber materials each comprise a woven fiber mat, a nonwoven fiber mat, continuous strand fibers, a fiber random structure, a fiber tissue, chopped fibers, milled fibers, a braid, a reinforced fiber mat, or any combination thereof.

11. The method of claim 8, wherein the core material comprises honeycomb paperboard, plastic honeycomb, aluminum honeycomb, balsa wood, rigid foam, compressed or uncompressed cotton fibers, compressed or uncompressed natural fibers, or compressed or uncompressed plastic fibers.

12. The method of claim 8, wherein the reaction mixture coated sandwich structure is laminated together with one or more outer or decorative layers.

13. The method of claim 12, wherein the outer layer comprises metal foil, metal sheet, thermoplastic composites of polymethyl methacrylate, acrylate-modified styrene acrylonitrile terpolymer, polycarbonate, polyamide, polybutylene terephthalate and / or polyphenylene ether in painted, paintable or pigmented form, glass-reinforced composite sheets, in-mold coatings and combinations thereof.

14. A polyurethane / polyisocyanurate molded article produced according to the method of claim 8.

15. The polyurethane / polyisocyanurate molded article according to claim 14, wherein the molded article is an automobile component.

16. The polyurethane / polyisocyanurate molded article of claim 15, wherein the automotive component is a load floor, a lower sound shield, a sound insulation chassis guard, a fairing shield, a splash shield, a body bottom panel, a chassis cover, a door module, a rear compartment kit, a leaf spring, a roof or a hood.

17. A method for producing a polyurethane / polyisocyanurate molded article comprising the steps of: a) placing a substrate in a mold; b) applying the reaction mixture of claim 1 to the surface of the substrate; c) applying a first fiber material having a first surface and a second surface to the first surface of the core material; d) applying a second fiber material having a first surface and a second surface to the second surface of the core material to form a sandwich structure having a first surface and a second surface, wherein the first fiber material and the second fiber material may be the same or different; e) placing the sandwich structure in the mold such that a first surface of the sandwich structure is adjacent to the reaction mixture; f) applying the reaction mixture of claim 1 to the second surface of the sandwich structure by spraying to form a sandwich structure coated with the reaction mixture; g) forming the sandwich structure coated with the reaction mixture in the mold at a temperature of about 100° C. to about 200° C., while curing the reaction mixture to form the polyurethane / polyisocyanurate molded article; f) removing the polyurethane / polyisocyanurate molded article from the mold; and e) optionally, post-treating the polyurethane / polyisocyanurate molding.

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