WO2014153053A1

WO2014153053A1 - Wall construction

Info

Publication number: WO2014153053A1
Application number: PCT/US2014/028854
Authority: WO
Inventors: Karl Richard NICHOLAS; Garry Balthes; Brad Joseph MARTIN; Mary Wetzel; John C. Norton; Marc Bennett FENWICK; Marc Lacounte
Original assignee: Basf Corporation; Tekmodo, Llc
Priority date: 2013-03-14
Filing date: 2014-03-14
Publication date: 2014-09-25

Abstract

Disclosed is a sandwich wall construction suitable for temporary housing, for example mobile homes, trailers, recreational vehicles and the like. The wall construction comprises, from the interior outwards, components (a) a planar cellular core having two faces, (b) adjacent to and covering each of the cellular core faces, a fiber mat, (c) adjacent to and covering at least one of the fiber mats, a thermoplastic polymer film and (d) adjacent to and covering the thermoplastic polymer film(s), an ultraviolet light cured clear coat, where the planar core is comprised of cellular polyurethane, polyisocyanate or a mixture of polyurethane and polyisocyanate and where the fiber mat comprises non-woven fibers or fabrics and a cured acrylic resin binder. The thermoplastic film is preferably a thermoplastic polyurethane film. The construction is free of formaldehyde, styrene and is free of adhesive layers.

Description

WALL CONSTRUCTION

FIELD

[0001] The present disclosure is aimed at lightweight, strong and durable wall constructions, in particular for mobile living spaces. The mobile living spaces are for instance recreational vehicles (RVs), mobile homes, or temporary trailers. The present wall constructions have no harmful emissions such as formaldehyde or styrene.

BACKGROUND

[0002] Current constructions for walls for mobile living spaces employ fiberglass reinforced plastics that include plywood for rigidity. These constructions have many shortcomings, most notably the emission of formaldehyde. Further, plywood based walls are very heavy and are susceptible to water damage.

[0003] There is a need for light weight, strong and VOC (volatile organic compound) free wall constructions for mobile living spaces. In particular, there is a need for such wall constructions that emit no formaldehyde.

SUMMARY

[0004] Accordingly, disclosed is a wall sandwich construction, which comprises from the interior outwards

(a) a planar cellular core having two faces,

(b) adjacent to and covering each of the cellular core faces, a composite fiber mat,

(c) adjacent to and covering at least one of the fiber mats, a thermoplastic polymer film and

(d) adjacent to and covering the thermoplastic polymer film or films, a cured clear coat,

where the planar core is comprised of cellular polyurethane, polyisocyanate or a mixture of polyurethane and polyisocyanate and

where the fiber mat comprises fibers or fabrics and a cured acrylic resin binder.

l DETAILED DESCRIPTION

[0005] Disclosed is a wall sandwich construction, which comprises from the interior outwards

(a) a planar cellular core having two faces,

[0006] The planar cellular core is a rigid foam structure comprised of

polyurethane, polyisocyanate or a mixture of polyurethane and polyisocyanate. Preferably, the cellular core is comprised of polyurethane. The foams are

commercially available and are well known by skilled artisans.

[0007] They are described for instance in U.S. Published Patent Applications No. 2012/0167510, the contents of which are incorporated herein by reference. The references cited therein are also incorporated herein by reference, U.S. Patent Nos. 7,612,120, 7,387,753, 7,838,568, 6, 1 17,375, 6044,604, 5,891 ,563 and 5,573,092, and U.S. Published Patent Applications No. 2004/0109983, 2003/0082365,

2003/0153656, and 2003/0032351 .

[0008] Polyurethanes are produced by a reaction between a polyol and an isocyanate compound. The foam recipe for the polyol includes for example a polyol, blowing agent, catalysts and surfactants, which are premixed and then mixed with isocyanate to initiate the reaction. The mixture is for example injected between the two fiber mats set within a static foam press and allowed to fill the center cavity.

[0009] Commercially available polyisocyanurates are made from isocyanate, catalysts, blowing agent and surfactants, modified with polyurethane. The resulting mixture may be poured as a liquid between the fiber mats or "fiber board panels." The liquid expands to form a solid cellular foam. [0010] The polyurethane, polyisocyanate or mixtures thereof may contain conventional additives, for instance flame retardants, fungicides, mildewcides, antistatic agents and the like.

[0011] The composite fiber mats comprise non-woven fibers or fabric, woven fabrics or non-crimp fabrics and a cured thermoset acrylic binder. Preferably, the fiber mats comprise non-woven fibers.

[0012] The fibers are natural, synthetic or glass fibers. Synthetic fibers are for instance carbon fibers. Natural fibers are for instance cellulosic bast fibers. The non- woven fibers may typically contain a small amount synthetic thermoplastic fiber, for instance polyethylene terephthalate fibers.

[0013] The acrylic binder is a cured aqueous based acrylic resin. The binder cures for instance through the carboxylic groups and a multi-functional alcohol.

[0014] Acrylic binders are polymers or copolymers containing units of acrylic acid, methacrylic acid, their esters or related derivatives.

[0015] The acrylic binders are for instance formed by aqueous emulsion polymerization employing (meth)acrylic acid (where the convention (meth)acrylic is intended to embrace both acrylic and methacrylic), 2-hydroxyethyl(meth)acrylate, 2- hydroxypropyl(meth)acrylate, 2-hydroxybutyl(meth)acrylate, methyl(meth)acrylate, ethyl(meth)acrylate, propyl(meth)acrylate, isopropyl(meth)acrylate,

butyl(meth)acrylate, amyl(meth)acrylate, isobutyl(meth)acrylate,

f-butyl(meth)acrylate, pentyl(meth)acrylate, isoamyl(meth)acrylate,

hexyl(meth)acrylate, heptyl(meth)acrylate, octyl(meth)acrylate,

isooctyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, nonyl(meth)acrylate,

decyl(meth)acrylate, isodecyl(meth)acrylate, undecyl(meth)acrylate,

dodecyl(meth)acrylate, lauryl(meth)acrylate, octadecyl(meth)acrylate,

stearyl(meth)acrylate, tetrahydrofurfuryl(meth)acrylate, butoxyethyl(meth)acrylate, ethoxydiethylene glycol (meth)acrylate, benzyl(meth)acrylate,

cyclohexyl(meth)acrylate, phenoxyethyl(meth)acrylate, polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, methoxyethylene glycol (meth)acrylate, ethoxyethoxyethyl(meth)acrylate, methoxypolyethylene glycol (meth)acrylate, methoxypolypropylene glycol (meth)acrylate,

dicyclopentadiene(meth)acrylate, dicyclopentanyl(meth)acrylate,

tricyclodecanyl(meth)acrylate, isobornyl(meth)acrylate, bornyl(meth)acrylate or mixtures thereof. [0016] Other monomers which can be co-polymerized with the (meth)acrylic monomers, generally in a minor amount, include styrene,

diacetone(meth)acrylamide, isobutoxymethyl(meth)acrylamide, /V-vinylpyrrolidone, N- vinylcaprolactam, /VJV-dimethyl(meth)acrylamide, f-octyl(meth)acrylamide, N,N- diethyl(meth)acrylamide, /V,/V'-dimethyl-aminopropyl(meth)acrylamide,

(meth)acryloylmorphorine; vinyl ethers such as hydroxybutyl vinyl ether, lauryl vinyl ether, cetyl vinyl ether, and 2-ethylhexyl vinyl ether; maleic acid esters; fumaric acid esters and similar compounds.

[0017] Multi-functional alcohols are for instance hydroquinone, 4,4'- dihydroxydiphenyl, 2,2-bis(4-hydroxyphenyl)propane, cresols or alkylene polyols containing 2 to 12 carbon atoms, including ethylene glycol, 1 ,2- or 1 ,3-propanediol, 1 ,2-, 1 ,3- or 1 ,4-butanediol, pentanediol, hexanediol, octanediol, dodecanediol, diethylene glycol, triethylene glycol, 1 ,3-cyclopentanediol, 1 ,2-, 1 ,3-or 1 ,4- cyclohexanediol, 1 ,4-dihydroxymethylcyclohexane, glycerol,

tris( ?-hydroxyethyl)amine, trimethylolethane, trimethylolpropane, pentaerythritol, dipentaerythritol, tripentaerythritol and sorbitol.

[0018] The aqueous based acrylic binders are commercially available under the ACRODUR name from BASF.

[0019] The aqueous based acrylic resin is infused in the fiber mat. That is to say, the fiber mat is impregnated with the acrylic resin. The fiber mats are compressed and cured with heat and pressure. Pressure is not required for curing, but for setting a desired thickness or density. For example, employed is a thermally equipped twin belt laminator or a step press to produce a wide (up to 10 feet) mat under a continuous process of about 5 meters per minute. Full fiber mats can be cut to as long as about 55 feet, allowing for the absence of seams. A flat press can cure an entire length at once with a cycle time of about 1 minute.

[0020] The aqueous based acrylic binder may be applied to the non-woven fibers or fabrics either through a dip-and-squeeze method, a curtain coater or a foam injection method. The mixture is dried to a low moisture content (about 4% to 7% by weight) prior to thermal curing. This is a fiber mat prepreg.

[0021] During initial heating and compression, compression release allows moisture to vent. The number of releases depends on the amount of moisture contained in the un-cured mat. The cured fiber mat does not contain significant amounts of water, for instance from 0% to about 3% or from about 0.1 percent to about 2% by weight, based on the dry weight. [0022] Once cured, the fiber mat does not significantly swell as is possible with various types of plywood or particle board.

[0023] A typical mat basis weight is about 1200 grams/square meter (gsm). For instance the basis weight of the fiber mats is from about 900 gsm to about 2000 gsm. The acrylic resin loading is from about 15% to about 50%, preferably from about 30% to about 40% by weight, of dried resin based on the finished mat weight.

[0024] The two fiber mats may be identical or different. They may have different fibers and/or be of different thicknesses and/or have different basis weights and/or levels of acrylic resin.

[0025] For instance one of the fiber mats may be from about 500 gsm to about 1000 gsm while the other is from about 1500 to about 1800 gsm, with the heavier fiber mat intended to be facing the exterior and bearing the at least thermoplastic polymer film. The interior fiber mat may be about 900 gsm.

[0026] A typical fiber mat is generally about 1 cm thick prior to curing. Once pressed and cured, the fiber mat is generally from about 1.5 to about 2 mm thick.

[0027] The thermoplastic film may comprise any suitable plastic, for instance the thermoplastic film is a polyvinylchloride (PVC), polyethylene, polyester,

polyetheretherketone (PEEK) or a polyurethane film. The thermoplastic polymer film is preferably a thermoplastic polyurethane (TPU) film.

[0028] Thermoplastic polyurethane resin is well known and is commercially available for instance under the trade names ELASTOLLAN (BASF) and

DESMOPAN (Bayer).

[0029] Commercially available TPU resin is generally based on either polyester or polyether polyol and either aromatic or aliphatic isocyanate. Preferably, the present TPU is aliphatic-based, that is, based on aliphatic isocyanate compounds, which provides for superior weather resistance.

[0030] The present thermoplastic film is applied to the outside face of the fiber mat via heat and pressure. The film may penetrate the pores of the fiber mat and mechanically bond thereto. Accordingly, a portion of the film may reside beneath the surface of the fiber mat. For instance, roughly 10% to about 60% of the film (by thickness) will be present beneath the fiber mat surface. For instance from about 20% or from about 30% to about 50% of the film will be present beneath the fiber mat surface. The remaining portion of the film creates a durable and smooth surface.

[0031] Conveniently, the thermoplastic film resin may be mixed with plastics additives such as pigments, dyes, flame retardants, hindered amine light stabilizers, ultraviolet light (UV) absorbers, anti-static agents and the like. Pigments are advantageously added to the thermoplastic resin to provide the film with a desired color. The pigments may be conventional pigments or effect pigments. Flame retardants and hindered amine light stabilizers are also advantageously added to the thermoplastic resin. Suitable ultraviolet light stabilizers are for instance selected from hydroxyphenylbenzotriazoles and hydroxyphenyl-s-triazines. The ultraviolet light absorbers (UVAs) and hindered amine light stabilizers (HALS) are well known commercial products available under the TINUVIN tradename (BASF).

[0032] The thermoplastic film resin is generally melt blended with the desired additives and then formed into pellets. Masterbatches of resin and additives may be employed. The film is then prepared from pellets via film extrusion methods.

[0033] The thermoplastic film may be extruded and pressed directly onto the fiber mat.

[0034] The thermoplastic film in total is from about 6 mils to about 12 mils thick.

[0035] The clear coat is applied to the exposed face of the thermoplastic film. The clear coat is a high solids coating, that is containing little or no water or solvent. Preferably the clear coat is a 100% solids, that is containing no volatile components.

[0036] The clear coat comprises ethylenically unsaturated compounds, one or more photoinitiators and further optional additives.

[0037] The ethylenically unsaturated compounds are well known and

commercially available, for example under the trade names DESMOLUX, Bayer or EBECRYL, Cytec. Preferably, the present ethylenically unsaturated compounds are oligomeric polyunsaturated compounds (prepolymers) such as acrylated epoxy resins, acrylated polyethers, acrylated polyurethanes, acrylated polyesters or unsaturated polyesters.

[0038] Preferably, the ethylenically unsaturated compounds are aliphatic urethane acrylates, also described as aliphatic allophanate urethane acrylates.

[0039] Reactive thinners may be employed to adjust to the desired viscosity, for example

mono-, di-, tri- or tetra-acrylic acid esters such as hexanediol diacrylate, tripropylene glycol diacrylate or trimethylolpropane diacrylate.

[0040] Preferably, the clear coat is 100% solids, that is containing no water, solvent or monomers.

[0041] The photoinitiators are well known and commercially available under the tradenames DAROCUR, IRGACURE or LUCIRIN (BASF). The photoinitiators are for example mono-, bis- or tris-acylphoshine oxides, phenylglyoxylates, benzophenone, benzophenone derivatives, acetophenone, acetophenone derivatives, such as a- hydroxycycloalkylphenylketones, a-hydroxyalkylphenylketones, 1-benzoyl-1-hydroxy- 1 -methylethane, dialkoxyacetophenones,

a-hydroxy- or a-aminoacetophenones, e.g., 4-morpholinophenyl-2-benzyl-2- dimethylamino-propionyl, 4-aroyl-1 ,3-dioxolanes, benzoin alkyl ethers and benzil ketals, further acylphosphine oxides, diisopropylxanthogen disulfide, ferrocenes or titanocenes.

[0042] The photoinitiators are added to the ethylenically unsaturated compounds for instance up to about 5% by weight, based on the weight of the ethylenically unsaturated compounds.

[0043] The clear coat formulation may advantageously contain further additives, for instance ultraviolet light (UV) absorbers and/or hindered amine light stabilizers. The formulation may contain further conventional additives such as anti-foaming agents and wetting agents.

[0044] The clear coat formulation may also be formulated so as to have a high gloss, gloss, semi-gloss, satin or matte finish, using known matting agents.

[0045] The clear coat is applied to the thermoplastic polymer film for example via roller, spray or curtain coating methods. After application, the clear coat formulation is cured via exposure to sunlight, ultraviolet light, electron beam, heat or

combinations thereof.

[0046] The cured clear coat contains reacted units of the ethylenically

unsaturated compounds. For instance units of oligomeric polyunsaturated

compounds (prepolymers) such as acrylated epoxy resins, acrylated polyethers, acrylated polyurethanes, acrylated polyesters or unsaturated polyesters.

[0047] Preferably, the cured clear coat contains units of aliphatic urethane acrylates.

[0048] The cured clear coat film thickness is generally from about 2 mils to about 5 mils, preferably from about 2 mils to about 4 mils, most preferably about 3 mils.

[0049] The thermoplastic polymer film and cured clear coat may be present on only one side of the wall construction, or alternatively on both sides. If only one side contains the thermoplastic film and clear coat, this side is intended to face the exterior and be exposed to the sun and weather. The side without the thermoplastic film and clear coat will face the interior of the walled space. [0050] The fiber mats, especially a fiber mat facing the interior not covered by a thermoplastic film and clear coat, may be formulated with pigments to provide a desired color. Likewise a fiber mat facing the interior may be covered with decorative film or paper (wall paper).

[0051] As mentioned above, a thermoplastic polymer film may be formulated with pigments to provide a desired color.

[0052] It is mentioned above that the thermoplastic film may also be formulated with flame retardants, light stabilizers, etc. The fiber mats may also be formulated with these additives.

[0053] The description of the present wall sandwich construction is from the interior outwards. The planar cellular core is the middle. From the middle outwards the wall comprises the fiber mats, the thermoplastic films and finally the cured clear coat.

[0054] In the case that each of the fiber mats is covered with a thermoplastic film, the thermoplastic films may be the same or different, that is of different compositions or thicknesses. In this case, only the thermoplastic film facing the exterior may be covered with the clear coat, or both may be covered with a clear coat.

[0055] The thickness of the entire wall construction depends on the desired properties; for instance sound absorption, R-value and structural integrity. The wall construction is generally from about 0.75 to about 3 inches thick, for instance about 1.75 inches thick. Often thicknesses of a wall are dictated by the profile of windows and doors available for assembly.

[0056] The walls are roughly 3 to 10 feet high and from 12 to 60 feet long.

[0057] The present wall constructions may advantageously employ no adhesive layers between the wall components. The present wall constructions emit no VOCs, no formaldehyde and no styrene or other monomers.

[0058] Other advantages of the present constructions are that they are mechanically stable, are seamless panels, may employ a variety of colors via incorporation of pigments, are field repairable with auto body techniques, good thermal shock resistance, high strength/low weight, easy handling and mobility, reduces production steps, high R insulation rating, high sound damping and weather and moisture resistant.

[0059] It is also contemplated that the present constructions may be employed to prepare curved or shaped parts in addition to flat panels. Fastening features may be designed within the structures to improve the process of assembly and reduce air and water ingress.

[0060] Specifically, the following embodiments are disclosed.

[0061] Embodiment 1. A wall sandwich construction, which comprises from the interior outwards

(a) a planar cellular core having two faces,

[0062] Embodiment 2. A wall construction according to embodiment 1 , where the planar core comprises polyurethane foam.

[0063] Embodiment 3. A wall construction according to embodiments 1 or 2, where the thermoplastic film is a thermoplastic polyurethane film.

[0064] Embodiment 4. A wall construction according to embodiments 1 , 2 or 3, where the fiber mat comprises non-woven cellulosic bast fibers and the acrylic resin is from about 15% to about 50% by weight dry resin, based on the weight of the fiber mat.

[0065] Embodiment 5. A wall construction according to any of the preceding embodiments, where the cured clear coat is a cured 100% solids coatings formulation.

[0066] Embodiment 6. A wall construction according to any of the preceding embodiments, where the cured clear coat is a cured coatings formulation comprising units of oligomeric polyunsaturated compounds selected from the group consisting of aliphatic urethane acrylates.

[0067] Embodiment 7. A wall construction according to embodiment 1 , where the planar core comprises polyurethane foam, the thermoplastic film is a

thermoplastic polyurethane film, the fiber mat comprises non-woven cellulosic bast fibers, the acrylic resin is from about 15% to about 50% by weight dry resin based on the weight of the fiber mat and the cured clear coat is a cured 100% solids coatings formulation comprising units of aliphatic urethane acrylates.

[0068] Embodiment 8. A wall construction according to any of the preceding embodiments, where the thermoplastic polymer film comprises one or more additives selected from the group consisting of pigments, dyes, flame retardants, hindered amine light stabilizers, ultraviolet light absorbers and anti-static agents.

[0069] Embodiment 9. A wall construction according to any of the preceding embodiments, where the cured clear coat comprises one or more additives selected from the group consisting of hindered amine light stabilizers and ultraviolet light absorbers.

[0070] Embodiment 10. A wall construction according to any of the preceding embodiments, which construction contains no formaldehyde, no styrene and no adhesive layers between the components.

[0071] Embodiment 11. A wall construction according to any of the preceding embodiments, where each of the fiber mats are from about 1 .5 to about 2 mm thick.

[0072] Embodiment 12. A wall construction according to any of the preceding embodiments, where each of the thermoplastic films in total are from about 6 mils to about 12 mils thick.

[0073] Embodiment 13. A wall construction according to any of the preceding embodiments, where each of the clear coats are from about 2 mils to about 5 mils thick. [0074] Embodiment 14. A wall construction according to any of the preceding embodiments, which in total is from about 0.75 to about 3 inches thick.

[0075] Embodiment 15. A wall construction according to any of the preceding embodiements where the two fiber mats are identical.

[0076] Embodiment 16. A wall construction according to any of the preceding embodiments where the two fiber mats are different.

[0077] Embodiment 17. A wall construction according to any of the preceding embodiments where each of the fiber mats are from about 1 .5 to about 2 mm thick, each of the thermoplastic films in total are from about 6 mils to about 12 mils thick, each of the clear coats are from about 2 mils to about 5 mils thick and which in total is from about 0.75 to about 3 inches thick.

[0078] Embodiment 18. A wall construction according to any of the preceding embodiments where a portion of the thermoplastic polymer film resides beneath the surface of the fiber mat.

[0079] Embodiment 19. A wall construction according to any of the preceding embodiments where from about 10% to about 60% of the thermoplastic polymer film is present beneath the fiber mat surface.

[0080] Embodiment 20. A wall construction according to any of the preceding embodiments where from about 20% to about 50% of the thermoplastic polymer film is present beneath the fiber mat surface.

[0081] Embodiment 21. Use of a wall construction according to any of the preceding embodiments as a wall in a recreational vehicle, a mobile home or a temporary trailer.

Example

[0082] A mixture of an aqueous based acrylic binder, ACRODUR, is applied to non-woven natural bast fibers by a dip-and-squeeze method and dried to a moisture content of about 7% by weight, preferably 5% by weight. A 10 foot long, 122 inch wide fiber mat is prepared via a thermally equipped twin belt laminator to produce a mat of about 2000 grams/m². The binder weight is 40% by weight, based on the weight of the finished thermally compressed mat.

[0083] Alternatively, the aqueous based acrylic binder is applied by foam injection. The fiber mat may be prepared from 50-60 feet long. The fiber mat may be prepared via a flat press.

[0084] Two thermally formed, 2 mm thick, finished fiber mats are set within a hydraulic foam press containing edge closeout framing. A commercial two part polyurethane foam is injected between the two fiber mats to fill the center cavity. The polyurethane core is 1.75 inches thick.

[0085] A commercial TPU resin, ELASTOLLAN L 1 160D10, is extruded into a film. The film is applied to the surface of one of the fiber mats via heat and pressure, in order to completely cover the fiber mat. The TPU film is 8 mils thick. About 40% of the TPU film resides beneath the surface of the fiber mat.

[0086] A 100% solids aliphatic urethane acrylate, DESMOLUX XP2666, is mixed with 3% by weight of LUCIRIN TPO acylphosphine oxide photoinitiator. To this clear coat formulation is also added an anti-foaming additive, a wetting agent, 1.5% by weight TINUVIN 400 s-triazine UV absorber and 1.5% by weight TINUVIN 292 hindered amine light stabilizer. The clear coat formulation is applied to the TPU film by curtain coating and cured with UV light. The cured clear coat film is 3 mil thick.

[0087] The side of the wall construction with the TPU film and cured clear coat is employed as the exterior wall exposed to the environment. The side without the TPU film and clear coat will face the interior of the vehicle or building.

[0088] The TPU resin may be formulated with pigments to provide a desired color.

Claims

WHAT IS CLAIMED IS:

1. A wall sandwich construction, which comprises from an interior outwards

(a) a planar cellular core having two faces,

(b) adjacent to and covering each of the two planar cellular core faces, a composite fiber mat,

(c) adjacent to and covering the composite fiber mat, a thermoplastic polymer film and

(d) adjacent to and covering the thermoplastic polymer film, a cured clear coat,

wherein the planar cellular core comprises cellular polyurethane,

polyisocyanate, or a mixture thereof, and

wherein the composite fiber mat comprises fibers or fabrics and a cured acrylic resin binder.

2. The wall construction according to claim 1 , wherein the planar cellular core comprises polyurethane foam.

3. The wall construction according to claim 1 or 2, wherein the thermoplastic polymer film is a thermoplastic polyurethane film.

4. The wall construction according to claims 1 , 2, or 3, where the composite fiber mat comprises non-woven cellulosic bast fibers and the cured acrylic resin binder is from about 15% to about 50% by weight dry resin, based on the weight of the composite fiber mat.

5. The wall construction according to claim 1 , where the cured clear coat is a cured 100% solids coatings formulation.

6. The wall construction according to any of the preceding claims, where the cured clear coat is a cured coatings formulation comprising units of oligomeric polyunsaturated compounds selected from the group consisting of aliphatic urethane acrylates.

7. The wall construction according to claim 1 , where the planar cellular core comprises polyurethane foam, the thermoplastic polymer film is a thermoplastic polyurethane film, the composite fiber mat comprises non-woven cellulosic bast fibers, the cured acrylic resin binder is from about 15% to about 50% by weight dry resin based on the weight of the composite fiber mat and the cured clear coat is a cured 100% solids coatings formulation comprising units of aliphatic urethane acrylates.

8. The wall construction according to any of the preceding claims, where the thermoplastic polymer film comprises one or more additives selected from the group consisting of pigments, dyes, flame retardants, hindered amine light stabilizers, ultraviolet light absorbers, and anti-static agents.

9. The wall construction according to any of the preceding claims, where the cured clear coat comprises one or more additives selected from the group consisting of hindered amine light stabilizers and ultraviolet light absorbers.

10. The wall construction according to any of the preceding claims, which construction contains no formaldehyde, no styrene, and no adhesive layers between the components.

1 1 . The wall construction according to any of the preceding claims, where the composite fiber mat is from about 1 .5 to about 2 mm thick.

12. The wall construction according to any of the preceding claims, where the thermoplastic polymer film in total is from about 6 mils to about 12 mils thick.

13. The wall construction according to any of the preceding claims, where the cured clear coat is from about 2 mils to about 5 mils thick.

14. The wall construction according to any of the preceding claims, which in total is from about 0.75 to about 3 inches thick.

15. The wall construction according to any of the preceding claims, comprising two identical composite fiber mats.

16. The wall construction according to any of the preceding claims, comprising two different composite fiber mats.

17. The wall construction according to any of the preceding claims, where a portion of the thermoplastic polymer film resides beneath a surface of the composite fiber mat.