Patent Description:
The invention also relates to a high gloss, multi-layer panel that can be easily repaired, once marred, to return the surface gloss to at least <NUM>% of the original surface gloss.

The invention further relates to articles made with the multi-layer paneling structure of the invention. The multi-layer structure can be used alone, or can be very thin and used as a replacement for an undercoating and coating on an article, such as a metal car part.

High gloss finishes are appealing, and are desired in many articles, including car interiors and exteriors, as well as in sports equipment, and lawn and garden equipment. One problem with typical gloss coatings and paints, is that the surface gloss layer is easily damaged due to scratching, marring and chemical exposure. Once marred, the thin surface coating is difficult to repair. Additionally, many coatings involve the use of volatile organic solvents which can cause health and/or environmental damage.

Certain structural plastics, such as high impact polystyrene (HIPS), acrylonitrile/butadiene/ styrene (ABS) resins, poly(vinyl chloride)(PVC) resins, and the like, exhibit attractive mechanical properties when extruded, molded, or formed into various articles of manufacture. Although these structural plastics are strong, tough and relatively inexpensive, the properties of their exposed surfaces are less than ideal. They are easily degraded by light; can be easily scratched; and are eroded by common solvents.

A common practice in the industry to apply another resinous material over the structural plastic to protect the underlying structural material and provide a surface that can withstand abuse associated with the use environment. Such surfacing materials are called "capstocks".

The capstock is generally much thinner than the structural plastic, typically being about <NUM>% to about <NUM>% of the total thickness of the composite comprising the capstock and structural plastic plies. For example, the thickness of the capstock can be about <NUM> to <NUM>, preferably <NUM> to <NUM>, and more preferably from <NUM> to <NUM> whereas the thickness of the structural plastic ply can be about <NUM> to about <NUM>.

As a class, acrylic resins, known for their excellent optical characteristics, resistance to degradation by sunlight, hardness, inertness to water and common chemicals, durability, and toughness, are capstocks of choice for various structural plastics, such as ABS sheet. The mechanical properties of the capstock generally are secondary to those of the structural plastic, but it is important that the capstock not adversely affect the mechanical properties of the composite.

Typical acrylic capstock materials, such as Arkema's SOLARKOTE® resins are described in <CIT>. These capstock materials are generally impact modified. A problem with impact modified single acrylic sheet, is that the impact modification diminishes both the gloss, and the chemical resistance of the cap layer.

Capstocks can be cross-linked to improve chemical resistance, but it is known to be difficult to make cross-linked capstocks thin enough to replace a painted finish.

<CIT>, and <CIT> describes automotive vehicle bodies having a single layer plastic outer body and an inner metal frame.

<CIT> discloses a multi-layer structure, comprising a high-gloss, mar resistant outer layer comprising a thermoplastic polymer selected from the group consisting of acrylic polymers, styrenic polymers an and a nano-sized inorganic filler and an inner layer.

There is a desire for a thin capstock material that has a very high gloss, and has a high impact resistance, where the high gloss resists gloss reduction damage caused by surface contacts with chemicals such as isopropyl alcohol, ethyl alcohol, methyl alcohol, sulphuric acid, phosphoric acid, toluene, isooctane, diisobutylene, and chemical mixtures such as gasoline fuel, diesel fuel, bio-fuel, bitumen, antifreeze, brake fluid, engine oil, Pancreatin (bird feces substitute), tree resin, and sunscreen. The high gloss finish should also be easily restored to within <NUM>% of the initial surface gloss.

It has surprisingly been found that a thin high gloss surface layer over a high-impact resistance interior layer, can be provided that will minimize the gloss reduction, and enable easy restoration of the high gloss finish to within <NUM>% of the original gloss.

Further advantages of the invention over traditional high gloss paint (used over an undercoating) in automotive applications include reduction of manufacturing steps and elimination of volatile organic solvents associated with coatings.

The multi-layer structure of the invention can pass an <NUM> exposure test, and should be cost competitive with traditional high gloss paint.

Further, while it is difficult to handle and process a typical cross-linked capstock where the cross-linking occurs during the polymerization, a post-polymerization reaction can be used to form useful cross-linking, such as by irradiation such as UV radiation and e-beam radiation.

In a first aspect, the invention relates to a multi-layer polymer structure comprising: a. a thin, high gloss outer polymeric cap layer, having a <NUM>° gloss of greater than <NUM>, preferably greater than <NUM>, and more preferably greater than <NUM>, as measured by a BYK Gardner Micro-Tri-Gloss <NUM>/<NUM>/<NUM> degree Gloss Meter, wherein said cap layer has a thickness of from <NUM> to <NUM>, preferably <NUM> to <NUM>, and more preferably from <NUM> to <NUM>, wherein said thin, high gloss outer polymeric cap layer comprises as the matrix polymer at least one acrylic and/or styrenic polymer; and b. an internal high impact resistant layer, wherein said high impact layer has an ASTM D256 notched Izod result at <NUM> of greater than <NUM>-cm/cm (<NUM> ft-lb/in), preferably greater than <NUM>-cm/cm (<NUM> ft-lb/in), and more preferably greater than <NUM>-cm/cm (<NUM> ft-lb/in), wherein said internal high impact resistant layer, comprises a thermoplastic selected from the group consisting of acrylonitrile butyl styrene (ABS), polyvinyl chloride (PVC), high impact polystyrene (HIPS), polycarbonate (PC), a blend of acrylic polymer and polylactic acid, impact modified acrylics, impact modified styrenics, polyamides, polyimides, polyurethanes, polyesters, and blends thereof.

In a second aspect, the thin high gloss outer cap layer has a heat deflection temperature (HDT), as measured by ASTM D648 (<NUM> MPa) of at least <NUM> (<NUM>°F) when prior to measurement, the samples are annealed at <NUM> for <NUM> hours then slow-cooled over <NUM> hours to <NUM>.

In a third aspect, the multi-layer polymer structure contains, in the thin, high gloss outer cap layer, less than <NUM> weight percent, preferably less than <NUM> weight percent, preferably less than <NUM> weight percent, and most preferably no impact modifiers.

In a further aspect, the thin, high gloss outer cap layer is chemical resistant and scratch resistant, and has a gloss retention of over <NUM>%, preferably over <NUM>% and a delta E of less than <NUM>, preferably less than <NUM> for each test material using the following procedure: for 6x6 inch samples conditioned at <NUM> for one hour and rubbed with ten back-and-forth strokes with a PIG Hazmat pad soaked with a test chemical, then wiped with a clean PIG Hazmat pad, washed, and reconditioned for at least one hour, and <NUM>° gloss re-measured. The test chemicals for the rub are chemicals such as butylene glycol and glyceryl stearate typically found in sunscreens. The cloths used in the test may be <NUM>"x14" PIG Hazmat Pads (MAT302) or <NUM>"x14" PIG Hazmat Pads (MAT423).

In a fifth aspect, the thin, high gloss outer cap layer contains a polymer having a weight average molecular weight of at least <NUM>,<NUM>/mol.

In an aspect outside the scope of the invention, the internal high impact resistant layer, is a thermoset, thermoplastic, and/or a polymer composite.

In a further aspect, the high-impact layer is a composite composition containing particles, nanoparticles, and/or fibers.

In a further aspect, the composite composition of any of the previous aspects is a fiber-reinforced acrylic composite, said composite formed from a blend of one or more acrylic polymers with one or more acrylic monomers that are impregnated into said fibers, followed by polymerization.

In an further aspect, the multi-layer structure further comprises a tie layer or adhesive layer between the exterior high gloss layer, and interior high impact layer.

In a further aspect, the multi-layer structure exists over a substrate, wherein said substrate is selected from metal; ceramics; and cellulosics; thermoplastic, elastomeric, and thermoset polymers having a thickness in the range <NUM> to <NUM> and preferably <NUM> to <NUM>.

In a further aspect, the multi-layer structure comprises two high gloss outer cap layers, one on either side of the internal high impact resistant layer.

In a further aspect, a method for restoring the gloss on a chemically or physically marred polymer multi-layer structure is presented, where the method includes the step of removing or hiding the mar.

In a further aspect, the method involves the mar restoration through the process of buffing, polishing, wiping, chemical treating, and/or sanding said multi-layer structure, wherein said gloss is restored to within <NUM>%, preferably <NUM>%, and most preferably within <NUM>% of the original gloss, as measured by a BYK Gardner Micro-Tri-Gloss <NUM>/<NUM>/<NUM> degree Gloss Meter,.

In a further aspect, the multi-layer polymeric structure is manufactured by thermoforming, in-mold decorating, sequential injection molding, coextrusion, resin transfer molding with in-mold decoration, or 3D printing (additive manufacturing).

In a further aspect, an article is presented which contains the thin multi-layer polymeric structure where the article is selected from the group consisting of exterior paneling, automotive body panels, automotive body trim, recreational vehicle body panels or trims, exterior panels for recreational sporting equipment, marine equipment, exterior panels for outdoor lawn, garden and agricultural equipment and exterior paneling for marine, aerospace structures, aircraft, public transportation applications, interior paneling applications, interior automotive trims, interior panels for marine equipment, interior panels for aerospace and aircraft, interior panels for public transportation applications, and paneling for appliances, furniture, and cabinets.

"Copolymer" as used herein, means a polymer having two or more different monomer units. "Polymer" is used to mean both homopolymer and copolymers. For example, as used herein, "PMMA" and "polymethyl methacrylate" are used to connote both the homopolymer and copolymers, unless specifically noted otherwise. (Meth)acrylate is used to connote both acrylates and methacrylates, as well as mixtures of these. Polymers may be straight chain, branched, star, comb, block, or any other structure. The polymers may be homogeneous, heterogeneous, and may have a gradient distribution of co-monomer units. All references cited are incorporated herein by reference.

As used herein, unless otherwise described, percent shall mean weight percent. Molecular weight is a weight average molecular weight as measured by GPC. In cases where the polymer contains some cross-linking, and GPC cannot be applied due to an insoluble polymer fraction, soluble fraction / gel fraction or soluble fraction molecular weight after extraction from gel is used.

"Multi-layer" as used herein describes a structure having at least two layers attached directly or indirectly to each other, wherein the exterior layer is a high-gloss capstock, and at least one interior layer is a high impact layer. The layers may be directly in contact with each other, or may contain one or more other layers in between, such as a tie layer, an adhesive layer, a vapor barrier, a color layer or special effects layer, etc. In one embodiment, the multi-layer structure has a high gloss capstock on either side of the interior high impact layer. This arrangement is especially useful where the multilayer structure is transparent or translucent, and the surfaces of both sides would be visible.

The exterior high gloss layer is an acrylic- and/or styrenic-based layer; is chemical resistant, mar resistant and scratch resistant, with any deterioration of the high gloss being restorable to within <NUM>% of the original gloss. The <NUM>° gloss of the exterior layer is greater than <NUM>, preferably greater than <NUM>, and more preferably greater than <NUM>, as measured by a BYK Gardner Micro-Tri-Gloss <NUM>/<NUM>/<NUM> degree Gloss Meter.

The exterior, high gloss layer may optionally contain <NUM>-<NUM> wt% nano-sized particles additives to improve the chemical resistance, mar resistance, scratch resistance, and/or improve the ability of the high gloss surface to be restored after incurring damage from chemical exposure, marring, and/or scratching. Useful nano-sized inorganic fillers include, but are not limited to silica, alumina, zinc oxide, barium oxide, molybdenum disulfide, boron nitride, tungsten disulfide, titanium oxide, nanographene, nanographite, graphite nanoplatelets, and graphite oxide nanoparticles.

The exterior, high gloss layer is thin, having a thickness of from <NUM> to <NUM>, preferably <NUM> to <NUM>, and more preferably from <NUM> to <NUM>.

The exterior, high gloss layer has a heat deflection temperature (HDT), of greater than <NUM> °F (or <NUM>) as measured by ASTM D648 (<NUM> MPa), when samples are annealed at <NUM>-<NUM> for <NUM> hours then slow-cooled over <NUM> hours to <NUM>.

The acrylic or styrenic polymer of the invention has a weight average molecular weight of between <NUM>,<NUM> and <NUM>,<NUM>/mol, and preferably from <NUM>,<NUM> and <NUM>,<NUM>/mol, as measured by gel permeation chromatography. The molecular weight distribution of the acrylic polymer may be monomodal, or multimodal with a polydispersity index greater than <NUM>. Copolymers containing comonomers that will lower the HDT of the copolymer, such as C<NUM>-<NUM> acrylates, should have a weight average molecular weight of greater than <NUM>,<NUM>/mol. In a preferred embodiment, an acrylic cap layer will contain predominately methyl methacrylate monomer units, and have less than <NUM> weight percent, and preferably less than <NUM> weight percent of comonomers. The acrylic capstock may also have comonomers such as methacrylic acid, tertiobutyl cyclohexanol methacrylate, alpha-methyl styrene, and other Tg increasing monomers, where the total co-monomer content can be up to <NUM>%.

In one embodiment the cap layer is a blend of an acrylic or styrenic polymer with up to <NUM> weight percent, preferably less than <NUM> weight percent, more preferably less than <NUM> weight percent % of polyvinylidene fluoride (PVDF) homopolymers or copolymers. A blend of acrylic polymers with less than <NUM> weight percent, preferably less than <NUM> weight percent of polylactic acid can also be used. The high gloss acrylic capstock can also be a crosslinked acrylic sheet with less than <NUM>% crosslinking agent.

In one embodiment, the exterior, high-gloss layer may be a polymer blend, containing the acrylic or styrenic polymer plus up to <NUM> wt%, preferably up to <NUM> wt% of one or more other compatible, miscible or semi-miscible polymers. One useful blend is a blend of a poly(meth)acrylic polymer or copolymer with acrylonitrile-styrene-acrylate (ASA) polymer.

In one embodiment, crosslinking is provided by a post-polymerization reaction, such as by the use of irradiation. Useful irradiation includes UV radiation, gamma radiation and e-beam. By using a post-polymerization cross-linking mechanism, a thinner cap layer that is easily processable can be achieved.

"Acrylic polymer" as used herein is meant to include polymers, copolymers and terpolymers formed from alkyl methacrylate and alkyl acrylate monomers, and mixtures thereof. The alkyl methacrylate monomer is preferably methyl methacrylate, which may make up from <NUM> to <NUM> percent of the monomer mixture. <NUM> to <NUM> percent of other acrylate and methacrylate monomers or other ethylenically unsaturated monomers, included but not limited to, styrene, alpha methyl styrene, acrylonitrile, and crosslinkers at low levels may also be present in the monomer mixture. Other methacrylate and acrylate monomers useful in the monomer mixture include, but are not limited to, methyl acrylate, ethyl acrylate and ethyl methacrylate, butyl acrylate and butyl methacrylate, iso-octyl methacrylate and acrylate, n-octyl acrylate, lauryl acrylate and lauryl methacrylate, stearyl acrylate and stearyl methacrylate, isobornyl acrylate and methacrylate, methoxy ethyl acrylate and methacrylate, <NUM>-ethoxy ethyl acrylate and methacrylate, isodecyl acrylate and methacrylate, tertiobutyl cyclohexyl acrylate and methacrylate, tertiobutyl cyclohexanol methacrylate, trimethyl cyclohexyl acrylate and methacrylate, methoxy polyethylene glycol methacrylate and acrylate with <NUM>-<NUM> ethylene glycol units, penoxyethyl acrylate and methacrylate, alkoxylated phenol acrylate, ethoxylated phenyl acrylate and methacrylate, epoxypropyl methacrylate, tetrahydrofurfuryl acrylate and methacrylate, alkoxylated tetrahydrofurfuryl acrylate, cyclic trimethylolpropane formal acrylate, carprolactone acrylate, dimethylamino ethyl acrylate and methacrylate monomers. Alkyl (meth) acrylic acids such as methacrylic acid and acrylic acid or C1-C8 esters thereof can be useful for the monomer mixture. Alkyl (meth) acrylic acids such as methacrylic acid and acrylic acid can be useful for the monomer mixture. Most preferably the acrylic polymer is a copolymer having <NUM> - <NUM> weight percent of methyl methacrylate units and from <NUM> to <NUM> weight percent of one or more C<NUM>-<NUM> straight or branched alkyl acrylate units.

Styrenic-based polymers include, but are not limited to, polystyrene, high-impact polystyrene (HIPS), acrylonitrile-butadiene-styrene (ABS) copolymers, acrylonitrile-styrene-acrylate (ASA) copolymers, styrene acrylonitrile (SAN) copolymers, methacrylate-butadiene-styrene (MBS) copolymers, styrene-butadiene copolymers, styrene-butadiene-styrene block (SBS) copolymers and their partially or fully hydrogenenated derivatives, styrene-isoprene copolymers, styrene-isoprene-styrene (SIS) block copolymers and their partially or fully hydrogenenated derivatives, and styrene-(meth)acrylate copolymers such as styrene-methyl methacrylate copolymers (S/MMA). A preferred styrenic polymer is ASA. The styrenic polymers of the invention can be manufactured by means known in the art, including emulsion polymerization, solution polymerization, and suspension polymerization. Styrenic copolymers of the invention have a styrene content of at least <NUM> percent by weight, preferably at least <NUM> percent by weight.

The capstock should contain less than <NUM> weight percent impact modifier, preferably less than <NUM> weight percent, more preferably less than <NUM> weight percent and most preferably less than <NUM> weight percent. In one preferred embodiment, the cap layer contains no impact modifier.

The thin multi-layer paneling structure of the invention has at least one high impact resistant interior layer. This could be an impact-resistant thermoplastic, a blend of thermoplastics where the blend demonstrates impact-resistance, a blend of one or more thermoplastics and one or more thermoplastic elastomers and/or thermoplastic vulcanizates where the blend demonstrates impact-resistance, a thermoset polymer or a polymer composite. The high impact layer has an ASTM D256 notched Izod result at <NUM> of greater than <NUM>-cm/cm (<NUM> ft-lb/in), preferably greater than <NUM>-cm/cm (<NUM> ft-lb/in), and more preferably greater than <NUM>-cm/cm (<NUM> ft-lb/in).

Useful high impact resistant thermoplastics include acrylonitrile butyl styrene (ABS) polyvinyl chloride (PVC), and high impact polystyrene (HIPS), polycarbonate (PC), a blend of acrylic polymer and polylactic acid, impact modified acrylics such as RNEW® from Arkema, impact modified styrenics, polyamides, polyimides, polyesters, polyurethanes, and blends thereof. Preferred thermoplastics are ABS and polycarbonate.

Useful composites include, but are not limited to, thermoplastic resins that are reinforced with particles or nanoparticles including but not limited to graphite, carbon nanotubes, and silica; and/or reinforced with fibers, including but not limited to glass fibers, carbon fibers, and natural fibers. The particles and/or nanoparticles may have a mechanical modulus greater than or less than the continuous phase. The fibers could be in the form of individual fibers, braided fibers, and woven or non-woven mats. Thermoplastic composites include those with a matrix of ABS, PVC, HIPS, acrylic polymers, polyamides, polyurethanes, styrenics, polyether ketone ketone, and polyether ether ketone. Useful thermoset matrices include, but are not limited to polyesters or epoxies.

In one embodiment, a composite is formed using an acrylic liquid resin system containing a blend of acrylic monomer, acrylic polymer and an initiator. The liquid resin system is used to impregnate fibers, followed by polymerization. ELIUM® resins from Arkema are a useful example of such a system.

In one embodiment, the interior high impact resistant polymer is a blend of an acrylic resin and a polyester, such as a polylactic acid.

The thickness of the entire multi-layer structure depends on the final application of that structure, but is typically in the range of <NUM> to <NUM> and preferably <NUM> to <NUM>.

The multi-layer structure of the invention may be manufactured by several different means, as known in the art. The structure could be formed by coextrusion, extrusion lamination, extrusion coating, in-mold decoration, sequential injection molding, thermo-forming of a coextruded sheet or cast sheet, RTM-TS (resin transfer molding with in-mold decoration), and 3D printing (additive manufacturing).

The thin multi-layer structure of the invention has several properties that make it especially useful in many application.

The high gloss cap has a <NUM>° gloss of greater than <NUM>, preferably greater than <NUM>, and more preferably greater than <NUM>, as measured by a BYK Gardner Micro-Tri-Gloss <NUM>/<NUM>/<NUM> degree Gloss Meter.

The high gloss cap is resistant to chemicals, marring, scratching, crazing, and color shift, as well as to gloss reduction. The most significant appearance change after surface chemical exposure for opaque colored samples is gloss reduction, which is used in the current invention to characterize the chemical damage and success of restoration.

The gloss of the high gloss cap can be easily restorable should damage occur. Since the cap layer is thicker than a typical coating, there is additional material to remove in order to restore the surface aesthetic. It can be restored by polishing, which cannot be achieved with a painted surface. Other means to facilitate restoration include, but are not limited to buffing, wiping, chemical treatment, and/or sanding.

The structure could be transparent or translucent, which is not possible for a painted automobile or other type of panel.

The multi-layer structure of the invention, because of its excellent gloss, mar and scratch resistance, and the ability to restore the gloss, is an excellent material for use in many applications and articles. These include, but are not limited to internal and exterior paneling, automotive body panels, auto body trim, recreational vehicle body panels or trims, exterior panels for recreational sporting equipment, marine equipment, exterior panels for outdoor lawn, garden and agricultural equipment and exterior paneling for marine, aerospace structures, aircraft, public transportation applications, interior paneling applications, interior automotive trims, interior panels for marine equipment, interior panels for aerospace and aircraft, interior panels for public transportation applications, and paneling for appliances, furniture, and cabinets.

Within this specification embodiments have been described in a way which enables a clear and concise specification to be written, but it is intended and will be appreciated that embodiments may be variously combined or separated without parting from the invention. For example, it will be appreciated that all preferred features described herein are applicable to all aspects of the invention described herein.

Chemicals such as butylene glycol and glyceryl stearate typically found in sunscreens are applied to plastic surfaces in this test. The high gloss acrylic capstock surfaces are exposed to sunscreen chemicals at <NUM> for <NUM> minutes and <NUM> hours. The detailed test method is as follows: For 6x6 inch samples conditioned at <NUM> for one hour and rubbed with ten back-and-forth strokes with a PIG Hazmat pad soaked with a test chemical, then wiped with a clean PIG Hazmat pad, washed, and reconditioned for at least one hour, and <NUM>° gloss re-measured. The test chemicals for the rub are a mixture of butylene glycol and glyceryl stearate typically found in sunscreens. The cloths used in the test may be <NUM>"x14" PIG Hazmat Pads (MAT302) or <NUM>"x14" PIG Hazmat Pads (MAT423).

After the chemical exposure at the designated temperatures, the samples were cooled down and stabilized at room temperature for an hour before being washed with de-ionized water and wiped clean. The starting surface gloss and final surface gloss are characterized by a BYK Gardner Micro-Tri-Gloss <NUM>/<NUM>/<NUM> degree Gloss Meter and the <NUM>° is recorded (measured parallel to the rubbing direction). The measurement unit conforms to the standards DIN <NUM>, ISO <NUM>, ASTM D <NUM> and BS <NUM> Part D <NUM>. Values reported are the percentage of surface gloss that is retained after chemical exposure.

The high gloss acrylic surface is buffed and polished with the following method. Apply tallow and rouge to a cotton muslin buffing wheel. Buff sample for <NUM>-<NUM> seconds with light pressure below the axis of the wheel; enough pressure to let the wheel graze the surface of the sample. Following the buffing step, apply light pressure on sample with a cotton flannel polishing wheel for <NUM> seconds to further smooth out the surface. After buffing and polishing, clean the acrylic surface with soap and water and dry with cotton cloth.

The high gloss acrylic surface is scratched according to the following method. A <NUM>" x <NUM>" injection molded high gloss acrylic plaque is conditioned at <NUM> ±<NUM>% relative humidity at <NUM> ± <NUM> for <NUM> hours. Then, the surface is scratched by a spherical asperity having a radius of curvature of <NUM> ± <NUM> and <NUM> N scratch load on a Taber multi-finger scratch tester Model <NUM>. The scratching speed is <NUM> ± <NUM>/s and the length of the scratch is <NUM>.

Samples exposed to scratching damaged were paper polished within <NUM> hour after scratching by the following method. A <NUM>" x <NUM>" polishing paper (<NUM>™ 281Q Wetordry™ <NUM> micron polishing paper) was wrapped around a dense sponge. Using light pressure and a circular polishing motion, the scratched acrylic surface was polished by hand with the polishing paper continuously for <NUM> minutes. After paper polishing the acrylic surface was washed with soap and water and dried with cotton cloth. The <NUM> surface gloss of a non-scratched region of the plaque was measured before and after paper polishing with a BYK Gardner Micro-Tri-Gloss <NUM>/<NUM>/<NUM> degree Gloss Meter as previously described.

The visibility of scratch damage is quantified by an optical microscopy method. A digital image of the scratched region of the surface is captured in bright-field mode with a Nikon ME600 optical microscope equipped with a Pixelink PL-D <NUM> color camera at 100x magnification. The image is converted to an RGB color format, where each pixel color is expressed by R, G and B values (integer values <NUM> to <NUM>) for the Red, Green and Blue components of the pixel color, according to the RGB color system. Then, the R, G and B values are measured for each pixel within two analysis regions of identical size and dimensions, A and B. Region A is entirely contained within the scratched region, and region B is adjacent to Region A and entirely contained within the non-scratched region. Both regions must contain an area greater than <NUM> pixels. For each region, the average R, G, and B values of all pixels are calculated. Finally, the Scratch Visibility Value is calculated according to: <MAT> Where RA, GA and BA are the average Red, Green and Blue color values, respectively, of all pixels in Region A. Likewise, RB, GB and BB are the average Red, Green and Blue color values, respectively, of all pixels in Region B. It follows that scratch visibility increases with increasing Scratch Visibility Value.

Chemicals such as butylene glycol and glyceryl stearate typically found in sunscreens can cause significant damage to acrylic materials at high temperatures (<NUM>), This Example demonstrates the removal of surface damages and/or surface residue and the restoration of surface gloss and color. Table <NUM> shows the gloss retention before and after <NUM> ± <NUM> seconds of buffing. The acrylic materials were exposed to a sunscreen that contains a mixture of butylene glycol and glyceryl stearate as main component at <NUM> for <NUM> hours before buffing, using the chemical resistance test method described above. After the initial <NUM> ± <NUM> seconds of buffing, the surface gloss of the high gloss acrylic capstock can be restored to as high as <NUM>% of the original <NUM>° surface gloss. To restore the high gloss surface to <NUM>% of the original gloss, repeated buffing was carried out as illustrated in Table <NUM>, where <NUM> minutes of total buffing time can restore the gloss to within <NUM>% of the original gloss.

Samples of acrylic capstocks were exposed to sunscreen at <NUM> according to the chemical resistance test method described.

Sample <NUM> is a black PMMA/EA copolymer having an EA comonomer content of <NUM> to <NUM>-wt% and a weight average molecular weight in the range of <NUM>,<NUM> to <NUM>,<NUM>/mol,.

Sample <NUM> is a black PMMA/MAA copolymer ( having a MAA comonomer content of <NUM>-<NUM> wt% and a weight average molecular weight in the range of <NUM>,<NUM> to <NUM>,<NUM>/mol),.

Both samples are tested in duplicates, and both samples exhibit more than <NUM>% gloss retention and minimal color change (delta E less than <NUM>), as shown in Table <NUM>.

Exterior paneling often incurs surface damage due to scratching and abrasion. This example demonstrates the utility of scratch resistant formulations such as those described in <CIT> for the exterior layer of high gloss exterior paneling. Also demonstrated is the restoration of a surface after scratching damage via paper polishing. <NUM>" x <NUM>" samples plaques were prepared by injection molding and then affixed to steel plates for scratch tests and paper polishing. Samples were subjected to scratching according to the scratching test method described above, and then paper polished according to the paper polishing method described above. The scratch visibility, as well as surface gloss before and after paper polishing are listed in Table <NUM>.

Sample <NUM> is a black PMMA/EA copolymer having an EA comonomer content of <NUM> to <NUM> wt% and a weight average molecular weight in the range of <NUM>,<NUM> to <NUM>,<NUM>/mol.

Sample <NUM> is the same as Sample <NUM>, with the addition of <NUM> wt% of Cabot CAB-O-SIL® TS622 fumed silica. Sample <NUM> was prepared by melt compounding the black PMMA/EA copolymer and Cabot CAB-O-SIL® TS622 fumed silica on a <NUM> Leistritz ZSE-27HP twin-screw extruder.

The initial gloss of Sample <NUM> and Sample <NUM> were above <NUM> points for <NUM>° gloss and above <NUM> points for <NUM>° gloss, despite the presence of nanoparticle reinforcement in Sample <NUM>. After scratching, the scratch visibility of Sample <NUM> (<NUM>) was significantly greater than Sample <NUM> (<NUM>). Visually, the scratch visibility of Sample <NUM> also appeared more severe than Sample <NUM>. After paper polishing, the gloss of both Sample <NUM> and <NUM> reduced, however the gloss retention of sample <NUM> (<NUM>%) was greater than sample <NUM> (<NUM>%). The scratch visibility after paper polishing reduced for both samples, with the greatest reduction for sample <NUM>. Sample <NUM> demonstrated relatively low <NUM>° gloss retention after paper polishing (<NUM>%). Sample <NUM> demonstrated the useful combination of high initial gloss, low scratch visibility both before and after paper polishing, , as well as excellent (<NUM>%) <NUM>° gloss retention after paper polishing.

Claim 1:
A multi-layer polymer structure comprising:
a. a thin, high gloss outer polymeric cap layer, having a <NUM>° gloss of greater than <NUM>, preferably greater than <NUM>, and more preferably greater than <NUM>, as measured by a BYK Gardner Micro-Tri-Gloss <NUM>/<NUM>/<NUM> degree Gloss Meter, wherein said cap layer has a thickness of from <NUM> to <NUM>, preferably <NUM> to <NUM>, and more preferably from <NUM> to <NUM>, wherein said thin, high gloss outer polymeric cap layer comprises as the matrix polymer at least one acrylic and/or styrenic polymer; and
b. an internal high impact resistant layer, wherein said high impact layer has an ASTM D256 notched Izod result at <NUM> of greater than <NUM>-cm/cm (<NUM> ft-lb/in), preferably greater than <NUM>-cm/cm (<NUM> ft-lb/in), and more preferably greater than <NUM>-cm/cm (<NUM> ft-lb/in), wherein said internal high impact resistant layer, comprises a thermoplastic selected from the group consisting of acrylonitrile butyl styrene (ABS), polyvinyl chloride (PVC), high impact polystyrene (HIPS), polycarbonate (PC), a blend of acrylic polymer and polylactic acid, impact modified acrylics, impact modified styrenics, polycarbonate, polyamides, polyimides, polyurethanes, polyesters, and blends thereof