Patent Publication Number: US-11649587-B2

Title: Low weight modular carpet components and methods of making the same

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a National Stage Application, filed under 35 U.S.C. § 371, of International Application No. PCT/US2018/050577, filed Sep. 12, 2018, which claims priority to U.S. application Ser. No. 15/703,195, filed Sep. 13, 2017, now U.S. patent Ser. No. 11/260,621; the contents of both of which are hereby incorporated by reference in their entirety. 
     BACKGROUND 
     The installation techniques traditionally used to install modular carpet components such as carpet tiles puts a large emphasis on the need to ensure that each component is individually flat when installed. Whereas the edges of larger broadloom carpet installations may be positioned adjacent walls and/or may be specifically pinned to a subfloor, the edges of at least some smaller carpet tiles are generally exposed (possibly in the center of a room or high-traffic area) and may not be directly secured relative to their respective neighboring tiles. Thus, manufacturers of carpet tiles must ensure that these tiles do not curl (such that the carpet tile edges curl upward away from the subfloor) or dome (such that the middle of the carpet tile moves upward away from the subfloor) once installed. Each of these possible defects may create trip hazards for individuals walking along the tiled floor, or may create unsightly gaps between adjacent tiles. Even when each carpet tile is individually secured to the underlying subfloor (e.g., via an adhesive), internal forces within the carpet tile tending to curl or dome may cause portions of the tile to break away from the adhesive and the subfloor. 
     Historically, carpet tiles have been relatively heavy to help ensure each tile remains flat against a subfloor. The weight of each tile is thought to overcome any internal forces tending to curl or dome the carpet tile, thereby ensuring that the tile itself remains flat once installed. However, because carpet tiles are relatively heavy, particularly in comparison to similarly-sized broadloom carpet, transportation and installation of carpet components may be relatively expensive and/or time consuming due to the additional effort needed to maneuver each weighty carpet tile. The weight of carpet tiles has also limited their usage to applications in which weight, once installed, is generally unimportant, such as residential or commercial buildings. Carpet tiles have been particularly challenging for use in the airline industry, in which weight is of paramount importance during the selection of components for installation in aircraft. 
     Accordingly, a need exists for low-weight and durable carpet tiles having desirable flatness characteristics. 
     BRIEF SUMMARY 
     In general a low-weight carpet tile and process for making the same are provided. The carpet tile may comprise a facecloth having a plurality of face yarns tufted through a primary backing, an extruded polymer secondary backing layer, and a reinforcing scrim layer partially embedded within the extruded polymer secondary backing layer. The top surface and bottom surface of the carpet tile are defined by the facecloth and the reinforcing scrim layer, respectively. A polymer-based resin may be extruded onto the facecloth to form an at least substantially uniform secondary backing layer, and the reinforcing scrim layer may be laid onto the extruded polymer secondary backing layer while the extruded polymer secondary backing layer remains above a softening temperature for the resin. The entire multi-layer web may then be passed through a nip to embed the reinforcing scrim layer into the extruded polymer secondary layer, and the entire web may be chilled. 
     Various embodiments are directed to a low-weight carpet tile having a total weight of less than 60 ounces per square yard (2.034 kg/m 2 ). The carpet tile comprises a tufted primary backing defining a top wear surface comprising a plurality of tufted fibers. The opposite, backside of the primary backing may be coated with a pre-coat layer to lock the carpet tufts into the primary backing. The coated primary backing has an extruded polymer secondary backing secured thereto, and the extruded polymer secondary backing has a reinforcing scrim layer embedded partially therein to define the bottom surface of the carpet tile. 
     Various embodiments are directed to a carpet tile comprising a facecloth comprising a primary backing and a plurality of face yarns extending through the primary backing, wherein the facecloth defines an upper surface of the carpet tile; an extruded polymer secondary backing layer bonded to the facecloth; and a reinforcing scrim layer bonded to a bottom surface of the extruded polymer secondary backing, wherein the reinforcing scrim layer defines in part a bottom surface of the carpet tile. The reinforcing scrim layer may comprise a plurality of fibers comprising at least one of glass fibers or polymer fibers. The plurality of fibers of the reinforcing scrim layer may be arranged in a nonwoven configuration, i.e. it may be nonwoven fibrous materials. 
     Moreover, the extruded polymer secondary backing may comprise a polyolefin, for example, in an amount between about 10-40 wt % of the weight of the extruded polymer secondary backing. The extruded polymer secondary backing may additionally comprise an inert filler material in an amount between about 20-80 wt % of the weight of the extruded polymer secondary backing. Moreover, the facecloth may additionally comprise a primary backing pre-coat layer between the primary backing layer and the extruded polymer secondary backing layer. 
     So according to a first aspect of the invention, a carpet tile is provided, the carpet tile comprising:
         a facecloth comprising a primary backing and a plurality of face yarns extending through the primary backing, wherein the facecloth defines an upper surface of the carpet tile;   an extruded polymer secondary backing layer having a top surface bonded to the facecloth and an opposite bottom surface; and   a reinforcing scrim layer bonded to the bottom surface of the extruded polymer secondary backing, wherein the reinforcing scrim layer defines at least a portion of a bottom surface of the carpet tile.       

     According to some embodiments, the reinforcing scrim layer may comprise a plurality of fibers and wherein the plurality of fibers comprise at least one of: glass fibers or polymer fibers. 
     According to some embodiments, the plurality of fibers may comprise polymer fibers comprising sheathed polyester core fibers. 
     According to some embodiments, the plurality of fibers may comprise glass fibers having a coating, preferably a nonirritating coating. According to some embodiments, the coating may comprise polyethylene. Such polyethylene coating is a non-irritating coating 
     According to some embodiments, the reinforcing scrim layer may comprises a nonwoven fibrous material, i.e. a plurality of nonwoven fibers. 
     According to some embodiments, the reinforcing scrim layer may comprise a plurality of polymer fibers and a plurality of glass fibers. 
     According to some embodiments, the extruded polymer secondary backing may comprise a polyolefin. 
     According to some embodiments, the extruded polymer secondary backing may comprise between about 10 to 40 wt % polyolefin, such as between 10 and 40% w. According to some embodiments, the extruded polymer secondary backing may comprise between about 20 to 80 wt % of a filler material, such as between 20 and 80% w. 
     According to some embodiments, the weight of the carpet tile may be between about 40 to 70 ounces per square yard (about 1.356 to about 2.373 kg/m 2 ), such as between 40 and 70 ounces per square yard (1.356 to 2.373 kg/m 2 ). According to some embodiments, the weight of the carpet tile may be between about 50 to 60 ounces per square yard (about 1.695 to about 2.034 kg/m 2 ) such as between 50 to 60 ounces per square yard (1.695 to 2.034 kg/m 2 ). 
     According to some embodiments, the facecloth further may comprise a primary backing pre-coat layer between the primary backing layer and the extruded polymer secondary backing layer. 
     According to a second aspect of the present invention, a method of manufacturing a carpet tile is provided, the method comprising:
         providing a facecloth, wherein the facecloth comprises a primary backing having a plurality of face yarns extending through a facecloth;   forming a multi-layer construction comprising the facecloth and a backing construction secured on a first side of the facecloth by:
           extruding a polymer sheet onto the first side of the facecloth such that a top surface of the polymer sheet is bonded to the facecloth; and   pressing a fibrous reinforcing scrim layer partially into a bottom surface of the extruded polymer sheet to bond the fibrous reinforcing scrim layer to the bottom surface of the extruded polymer sheet such that the fibrous reinforcing scrim layer defines at least a portion of a bottom surface of the carpet tile.   
               

     According to some embodiments, pressing the fibrous reinforcing scrim layer partially into the extruded polymer sheet may comprise compressing the multi-layer construction between nip rollers. 
     According to some embodiments, the method further may comprise chilling the multi-layer construction. 
     According to some embodiments, the method further may comprise steps for cutting the carpet web into a plurality of carpet tiles. 
     According to some embodiments, extruding a polymer sheet may comprise extruding a polyolefin-based resin, wherein the polyolefin-based resin comprises between about 10 to 40 wt % polyolefin, such as between 10 and 40% w, and between about 20 to 80 wt % of a filler material, such as between 20 and 80% w. 
     According to some embodiments, pressing the fibrous reinforcing scrim layer partially into the extruded polymer sheet may comprise pressing a nonwoven fiber mat partially into the extruded polymer sheet. 
     According to some embodiments, the fibrous reinforcing scrim layer may comprise at least one of: fiberglass fibers or polymer fibers. 
     According to some embodiments, said steps for extruding a polymer sheet onto the first side of the facecloth and pressing a fibrous reinforcing scrim layer partially into the extruded polymer sheet may collectively form a backing construction having a weight between about 20 to 30 ounces per square yard (about 0.678 to about 1.017 kg/m 2 ), such as between 20 to 30 ounces per square yard (0.678 to 1.017 kg/m 2 ). 
     According to some embodiments, providing a facecloth may comprise providing a primary backing web having a weight between about 18 to 30 ounces per square yard (about 0.610 to about 1.017 kg/m 2 ); and wherein the multi-layer construction has a weight between about 38 to 60 ounces per square yard (about 1.288 to about 2.034 kg/m 2 ). According to some embodiments, providing a facecloth may comprise providing a primary backing web having a weight between 18 to 30 ounces per square yard (0.610 to 1.017 kg/m 2 ); and wherein the multi-layer construction has a weight between 38 to 60 ounces per square yard (1.288 to 2.034 kg/m 2 ). 
     So certain embodiments are directed to a method of manufacturing a carpet tile, the method comprising providing a facecloth, wherein the facecloth comprises a primary backing having a plurality of face yarns extending through a facecloth; forming a multi-layer construction comprising the facecloth and a backing construction secured on a first side of the facecloth by: extruding a polymer sheet onto the first side of the facecloth; pressing a fibrous reinforcing scrim layer partially into the extruded polymer sheet to bond the fibrous reinforcing scrim layer to the bottom surface of the extruded polymer sheet such that the fibrous reinforcing scrim layer defines at least a portion of a surface of the carpet tile; and, in certain embodiments, chilling the multi-layer construction. In certain embodiments, extruding the polymer sheet comprises extruding a polyolefin-based resin comprising between about 10-40 wt % polyolefin and between about 20-80 wt % of a filler material, measured as portions of the weight of the resin. Moreover, pressing the fibrous reinforcing scrim layer partially into the extruded polymer sheet comprises pressing a fiber mat partially into the extruded polymer sheet. 
     The methods according to the second aspect of the invention, may provide carpet tiles according to the first aspect of the invention. 
     According to a third aspect of the invention, a carpet tile secondary backing resin is provided, which resin comprising:
         a polyolefin material provided in the range of between about 10 to 40 wt % of the weight of the resin, such as between 10 to 40 wt %;   an inert filler material provided in the range of between about 50 to 80 wt % of the weight of the resin, such as between 50 to 80% w;   a viscosity modifier provided in the range of between about 1 to 3 wt % of the weight of the resin, such as between 1 to 3 wt %; and   one or more additional additives collectively provided in the range of between about 0.5 to 15 wt % of the weight of the resin, such as between 0.5 to 15 wt %.       

     According to some embodiments, the polyolefin material may comprise at least one of: 1-propene, ethylene copolymer; ethylene-propylene copolymer; or propylene homopolymer. 
     So certain embodiments are directed to a carpet tile secondary backing resin comprising: a polyolefin material provided in the range of between about 10 to 40 wt % of the weight of the resin; an inert filler material provided in the range of between about 50 to 80 wt % of the weight of the resin; a viscosity modifier provided in the range of between about 1 to 3 wt % of the weight of the resin; and one or more additional additives collectively provided in the range of between about 0.5 to 15 wt % of the weight of the resin. In certain embodiments, the polyolefin material comprises at least one of 1-propene, ethylene copolymer; ethylene-propylene copolymer; or propylene homopolymer. 
     The resin according to the third aspect of the invention may be used to provide carpet tiles according to the first aspect of the invention, and/or may be used in methods according to the second aspect of the invention. 
     The independent and dependent claims set out particular and preferred features of the invention. Features from the dependent claims may be combined with features of the independent or other dependent claims, and/or with features set out in the description above and/or hereinafter as appropriate. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein: 
         FIG.  1    is a side cutaway view showing various components of a carpet tile according to one embodiment; 
         FIG.  2    is a schematic diagram of a portion of a manufacturing line utilized to produce carpet tiles according to various embodiments; and 
         FIG.  3    is a flowchart showing various steps involved in production of a carpet tile according to various embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     The present disclosure more fully describes various embodiments with reference to the accompanying drawings. It should be understood that some, but not all embodiments are shown and described herein. Indeed, the embodiments may take many different forms, and accordingly this disclosure should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like numbers refer to like elements throughout. 
     Various embodiments are directed to a low-weight, dimensionally stable carpet tile that is resistant to both doming and curling. The carpet tile is a multi-layer carpet tile comprising a facecloth (comprising a primary backing, face yarn, and optionally a pre-coat layer), bonded to a backing construction comprising an extruded polymer secondary backing layer and a fibrous reinforcing scrim layer (e.g., woven or nonwoven) bonded to (e.g., partially embedded in) the extruded polymer secondary backing layer to define, at least in part, the bottom surface of the carpet tile. The low weight carpet tile product has a total weight of less than 60 ounces per square yard (2.034 kg/m 2 ) while remaining resistant to deformation (dimensional deformation, curling, or doming) due at least in part to the location of the reinforcing scrim layer on the bottom surface of the carpet tile. Moreover, at least a portion of the reinforcing scrim layer is exposed on the bottom surface of the carpet tile (e.g., protruding from the bottom surface of the extruded polymer secondary backing), and at least a portion of the fibers of the reinforcing scrim layer may be coated with a nonirritating coating to prevent skin irritation for installers of the carpet tiles. 
     Carpet Tile 
     Referring to the figures, in which like numerals refer to like elements through the several figures,  FIG.  1    is a cross sectional view of a carpet tile  100  in accordance with various embodiments of the present invention. In the illustrated embodiment, the carpet tile  100  includes face yarn  105 , which may be either tufted or woven into a primary backing  110  to form a facecloth  111 . The face yarn  105  may be made from various materials, both natural and synthetic, such as nylon 6, nylon 6,6, cotton, wool, nylon, acrylic, polyester, polyamides, polypropylene, and other polyolefins. The face weight of the face yarn  105  can be approximately 5 ounces per square yard (0.170 kg/m 2 ) to approximately 50 ounces per square yard (1.695 kg/m 2 ). 
     The primary backing  110  may be formed from a substrate such as a woven substrate, a tape yarn substrate, and/or other substrate construction that imparts stability to the carpet tile  100 . The substrate may be made from a polyester, such as poly(ethylene terephthalate) [PET], poly(trimethylene terephthalate) [PTT], poly(butylene terephthalate) [PBT], poly(ethylene terephthalate-co-isophthalate), poly(ethylene naphthalenedicaroxylate) [PEN], and copolymers thereof, and/or combinations thereof, with PET being preferred. In certain embodiments, the primary backing  110  may comprise a low melt polyester material configured to bind the various fibers together upon application of heat to the primary backing. The substrate may also comprise sheathed fibers, which may comprise a polyester core surrounded by a polyamide and/or polyolefin sheath. Typically, the polyester core may be made from PET, PTT, PBT, PEN, poly(ethylene terephthalate-co-isophthalate) and copolymers thereof. The polyamide sheath may be made from polycaprolactam [nylon 6], poly(7-heptanamide) [nylon 7], polycapryllactam [nylon 8], poly(9-nonanamide) [nylon 9], poly(tetramethylene adipamide) [nylon 4,6], poly(hexamethylene adipamide) [nylon 6,6], poly(methylene-4,4′-dicyclohexylene dodecanediamede), poly(1,4-cyclohexylenedimethulene suberamide), poly(m-phenylene isophthalamide), and poly(p-phenylene terephthalamide), with polycaprolactam [nylon 6] being the preferred polyamide. In certain embodiments, the primary backing  110  may be formed using a woven substrate using any conventional natural or synthetic woven material, such as cotton, jute, rayon, paper, nylon, polypropylene and other polyolefins, polyamides, polyesters, and the like. 
     The face yarn  105  may be tufted through the primary backing  110  so that the ends of the face yarn  105  extend in an outwardly direction from the topside of the primary backing  110  to form an upper surface of the carpet tile  100 . Typically the face yarn is tufted into the primary backing  110  at a weight of approximately 2.6 ounces per square yard (0.088 kg/m 2 ) to approximately 5.9 ounces per square yard (0.200 kg/m 2 ), and more preferably approximately 3 ounces per square yard (0.102 kg/m 2 ). The tufting may be performed using conventional techniques that are well known in the art. Furthermore, the tufted face yarn  105  loops may be left as uncut to form an uncut pile carpet, cut to form a cut pile carpet, or partially cut to form a tip sheared carpet, as is well known in the art. 
     In certain embodiments, the facecloth  111  includes a pre-coat layer  115  that is applied to a bottom surface of the primary backing  110 . The pre-coat layer  115  penetrates the tufted face yarn  105  and encapsulates individual ends of the yarn bundles to at least partially bind the tufted face yarn  105  to the primary backing  110 . This may prevent one end of an individual fiber from being pulled out of the carpet backing during the manufacturing process. The pre-coat layer  115  may also act as a tackifier to provide an acceptable binding surface for a subsequent polymer layer. In an exemplary embodiment, the pre-coat layer  115  comprises a hot melt adhesive (HMA) that contains a tackifying resin or agent alone or in combination with polyethylene. In various embodiments, the pre-coat layer  115  comprises an aqueous-latex based polymer configured to support the face yarn  105  within the primary backing  110  upon drying. In certain embodiments, the pre-coat layer  115  comprises butadiene acrylate based polymers, vinyl acetate ethylene, vinyl acetate-ethane copolymers, and/or latex based compounds. The pre-coat layer  115  may include one or more other compositions, such as inert filler materials (e.g., fly ash) as discussed in reference to the extruded polymer secondary backing layer  120  herein. 
     The pre-coat layer  115  may be applied to a bottom surface of the primary backing  110  in the range of approximately 2 ounces per square yard (0.068 kg/m 2 ) to approximately 20 ounces per square yard (0.678 kg/m 2 ), and more preferably in the range of approximately 8 ounces per square yard (0.27 kg/m 2 ) to approximately 12 ounces per square yard (0.407 kg/m 2 ). 
     Disposed on a bottom surface of the facecloth  111  is a backing construction comprising an extruded polymer secondary backing layer  120  and a reinforcing scrim layer  130 . The backing construction is arranged such that the extruded polymer secondary backing layer  120  is positioned between the reinforcing scrim layer  130  and the facecloth  111 . In such an embodiment, a first (top) side of the extruded polymer secondary backing layer  120  is bonded to the facecloth  111  and a second (bottom) side of the extruded polymer secondary backing layer  120  is bonded to the reinforcing scrim  130 . The extruded polymer secondary backing layer  120  is embodied as a resin comprising one or more components collectively configured to give the resulting carpet tile  100  a flat overall appearance without substantial doming (a central portion of the carpet tile  100  rising relative to the edges such that a top surface of the carpet tile  100  is convex) or curling (the edges of the carpet tile  100  rising relative to the central portion such that a top surface of the carpet tile  100  is concave). The resin of the extruded polymer secondary backing layer  120  may comprise a polyolefin or a mixture of one or more polyolefins together with one or more other polymers. For example, the resin may comprise polyethylene and/or polypropylene. As specific examples, the polyolefin polymer is embodied as 1-propene, ethylene copolymer or ethylene-propylene copolymer. In certain embodiments, the resin of the extruded polymer secondary backing layer  120  comprises the polyolefin or polyolefin mixture in an amount between about 10-40 wt % of the resin of the extruded polymer secondary backing layer  120  (and of the extruded polymer secondary backing layer  120  itself). 
     The resin extruded polymer secondary backing layer  120  may additionally comprise one or more additives, such as an inert filler material, a colorant, an antioxidant, a tackifier, a viscosity modifier, a flame retardant, and/or the like. 
     The inert filler material may constitute the majority of the resin of the extruded polymer secondary backing layer  120  (by weight), and may function as a low cost material that adds weight to the extruded polymer secondary backing layer  120  to aid in forming an at least substantially flat carpet tile  100 . For example, the inert filler material may constitute between about 20-80 wt % of the resin and/or the extruded polymer secondary backing layer  120 . 
     The inert filler material may be made from carbonates such as calcium carbonate (CaCO 3 ), cesium carbonate (CsCO 3 ), strontium carbonate (SrCO 3 ), and magnesium carbonate (MgCO 3 ); sulfates such as barium sulfate (BaSO 3 ); oxides such as iron oxide (Fe 2 O 3  or Fe 3 O 4 ), aluminum oxide (Al 2 O 3 ), tungsten oxide (WO 3 ), titanium oxide (TiO 2 ), silicon oxide (SiO 2 ); silicates, such as clay; metal salts; fly ash and the like. 
     Additionally, the inert filler material may be made from post-consumer products, such as post-consumer glass, post-consumer carpets and/or other post-consumer recycled materials. In cases where the inert filler is made from post-consumer glass, the post-consumer glass is ground into a fine glass powder before it is added as filler. The glass cullet may be made from automotive and architectural glass, also known as plate glass, flint glass, E glass, borosilicate glass, brown glass (bottle glass), green glass (bottle glass), and coal fly ash, or a combination thereof. In the case where post-consumer carpet is used as the inert filler material, the post-consumer carpet maybe ground into a fine cullet and added to the hot melt adhesive. In addition to the post-consumer carpet, remnants and trimmings of carpet (e.g., comprising trim waste from cutting carpet tiles from rolls of carpet, sometimes referred to as window waste), fine waste fibers that are a result of the shearing process, and the like, that are produced as a by-product during the manufacturing process may also be used to form the inert filler material. 
     The filled or unfilled polymer may also contain a colorant, such as carbon black or another colorant(s) to provide color and increase the opaqueness of the extruded polymer secondary backing layer  120 . Typically, the colorant may be present in an amount less than or equal to approximately 1 wt % the filled or unfilled resin and extruded polymer secondary backing layer  120 . For example, the colorant may be present in an amount between about 0.1-0.5 wt % of the extruded polymer secondary backing layer  120 . As a specific example, the colorant may be present in an amount of approximately 0.1 wt % of the resin and the extruded polymer secondary backing layer  120 . 
     Moreover, to reduce the possibility of thermo-oxidation degradation, the polymer may also contain one or more antioxidants. Some suitable antioxidants include, but are not limited to amines, 2,2′-methylene bis-(4-methyl-6-tert-butylphenol), 2,4,6-tri-tert-butylphenol, 2,6-di-tert-butyl-4-methylphenol, 4,4′-thio-bis-(6-tert-butyl-m-cresol), butylated hydroxy anisole, butylated hydroxy toluene, bis(hydrogenated tallow alkyl),oxide; tris(2,4-ditert-butylphenyl)phosphite and 1,3,5 triazine-2,4,6(1H, 3H, 5H)-trione,1,3,5,tris ((3,5 (1 dimethylethyl))-4-hydroxyphenyl)methyl. Typically, the antioxidant may be present in the filled or unfilled extruded polymer secondary backing layer  120  in an amount less than or equal to approximately 2 wt % of the resin and/or the extruded polymer secondary backing layer  120 , such as between about 0.05-0.5 wt % of the resin and/or the extruded polymer secondary backing layer  120 . 
     Moreover, the extruded polymer secondary backing layer  120  may additionally include one or more tackifiers to aid in forming a strong mechanical bond with the pre-coat layer  115  (if present), the primary backing  110 , and/or the reinforcing scrim layer  130  discussed in further detail below. 
     The resin of the polymer secondary backing layer  120  may additionally include one or more viscosity modifiers and/or compatibilizers, such as, for example, olefins of higher or lower molecular weight than the resin discussed herein or ethylene maleic anhydride copolymer, to ensure proper flow and bonding of the resin within filler and polymers when applying onto a facecloth  111 . The viscosity modifier may be present in an amount between about 0.1-3 wt % of the resin and the extruded polymer secondary backing layer  120 . 
     In certain embodiments, the resin of the extruded polymer secondary backing layer  120  may additionally comprise one or more flame retardants, such as, but not limited to, aluminum trihydrate (ATH) or magnesium hydroxide (MgOH) for applications where flame-retardancy is desired. One or more flame retardants may be necessary to comply with applicable regulations regarding the installation and/or usage of carpet tiles in certain applications, for example, when such carpet tiles are installed in transportation vehicles (e.g., buses, aircraft, and/or the like). 
     Example resins of the extruded polymer secondary backing layer  120  are shown in tables 1 and 2, below, with example amount ranges that may be included for each component. The inventors found that both of these example extruded polymer secondary backing layer  120  formulations provided a lightweight carpet tile having a strong mechanical bond between the various layers of the carpet tile  100  and a substantially flat carpet tile profile. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                 Component 
                 wt % range (of resin) 
               
               
                   
                   
               
             
            
               
                   
                 1-propene, ethylene copolymer 
                 20-40 
               
               
                   
                 Primary antioxidant 
                 0.1-0.3 
               
               
                   
                 Secondary antioxidant 
                 0.05-0.15 
               
               
                   
                 Ethylene maleic anhydride copolymer 
                 1-3 
               
               
                   
                 Calcium carbonate (limestone) 
                 Balance 
               
               
                   
                 Carbon black concentrate 
                 0.1-0.5 
               
               
                   
                   
               
            
           
         
       
     
     The amount of limestone being the balance may range typically from 60 to 80 wt %, but can e.g. also be between 56.05 wt % and 78.75 wt %. An example of a composition was made having following ingredients: 35% w of 1-propene, Ethylene copolymer, being Adflex Z108S, available from Lyondell, 0.2% W of primary antioxidant Tris(2,4-DI-tert-butylphenyl)phosphite being Irgafos 168, available from BASF, 0.1% w of a secondary antioxidant 1,3,5-Tris(3,5-di-tert-butyl-4-hydroxy benzyl)-s-triazine-2,4,6-(1H,3H,5H)trione, being Irganox 3114, available from BASF, 2% w of ethylene maleic anhydride copolymer available as Integrate (NP 507030), from Lyondell, 0.2% carbon black masterbatch, being Black PE 907 Conc available from Modern Dispersions and the balance being limestone available from Huber as RECAL PRE-C 20. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 2 
               
               
                   
                   
               
               
                   
                 Component 
                 wt % range (of resin) 
               
               
                   
                   
               
             
            
               
                   
                 Ethylene-propylene copolymer 
                 10-30 
               
               
                   
                 Propylene homopolymer 
                 0.1-3     
               
               
                   
                 Tackifier 
                  1-15 
               
               
                   
                 Ethylene maleic anhydride copolymer 
                 1-3 
               
               
                   
                 Calcium carbonate (limestone) 
                 Balance 
               
               
                   
                 Carbon black concentrate 
                 0.1-0.5 
               
               
                   
                   
               
            
           
         
       
     
     Though the amount of ethylene maleic anhydride copolymer may vary between 0.1 and 3 wt %, preferably the amount of ethylene maleic anhydride copolymer is between 1 and 3 wt %. 
     The amount of limestone being the balance may range typically from 48 to 80 wt %, but can e.g. also be between 48.5 wt % and 87.9 wt %. Again an example of such composition was made having following ingredients: 25% w of Ethylene-Propylene copolymer, being Vistamaxx 6502, available from ExxonMobil, 1.5% w of Propylene homopolymer, being Achieve 6936G2, available from ExxonMobil, 10% w of a resin tackifier, being Nevtac 201, available from Neville Chemical, 2% w of ethylene maleic anhydride copolymer available as Exxelor PE1040 from ExxonMobil, 0.2% carbon black masterbatch, being Black PE 907 Conc available from Modern Dispersions, the balance being limestone available from Huber as RECAL PRE-C 20. 
     The term “wt %” and “% w” are identical and refers to the weight of the ingredient over the total weight of the composition in which it is present, expressed as percentage. 
     Referring again to  FIG.  1   , the carpet tile  100  additionally comprises a reinforcing scrim layer  130  partially embedded within the extruded polymer layer  120  to define, at least in part, the bottom surface of the carpet tile  100 . The reinforcing scrim layer  130  imparts dimensional stability to the finished carpet tile  100 . Because the reinforcing scrim layer  130  is positioned on the bottom surface of the carpet tile  100 , the reinforcing scrim layer  130  provides additional support against curling and/or doming of the carpet tile. 
     The reinforcing scrim layer  130  may comprise a fibrous material provided in either a woven or non-woven configuration. Particularly when provided on the bottom surface of the carpet tile  100 , a woven fibrous reinforcing scrim layer  130  contributes to providing desirable flatness characteristics to the resulting carpet tile  100  while nonwoven fibrous materials aid in preventing shrinkage or expansion of the resulting carpet tile  100 . The desirable flatness characteristics may be at least substantially free from doming (a central portion of the carpet tile  100  rising relative to the edges to provide a convex top surface of the carpet tile  100 ) or curling (the edges of the carpet tile  100  rising relative to the central portion to provide a concave top surface of the carpet tile  100 ) that traditionally results from providing a polymer backing on a carpet tile  100 . As certain polymers cool and/or harden on a back of a carpet tile  100 , those polymers tend to shrink and pull other portions of the carpet tile  100  (causing the carpet tile to deform and dome) or expand and pull other portions of the carpet tile  100  (causing the carpet tile to deform and curl). Placing a reinforcing scrim layer  130  on the bottom portion of carpet tile  100  counteracts the deformation forces on the carpet tile  100  caused by the polymer backing cooling and hardening. Given these two distinct characteristics of woven and nonwoven fibrous scrim materials, certain carpet tiles  100  may comprise a reinforcing scrim layer  130  comprising both woven and nonwoven fibrous materials. 
     The fibrous materials themselves may constitute any number of natural or synthetic materials. For example, the fibrous materials may be embodied as glass fibers, which may be coated with a nonirritating coating (e.g., a thermoplastic or thermoset coating), such as a polyethylene. The nonirritating coating may be applied to the fibers individually (e.g., to create a sheathed fiber) or the nonirritating coating may be applied to the woven or non-woven reinforcing scrim layer  130 . For example, the nonirritating coating may be applied to a bottom surface (e.g., the exposed bottom surface) of the reinforcing scrim layer  130 . The nonirritating coating may prevent installers from coming into contact with irritating fibrous materials while laying the carpet tiles  100 . The fibrous material may additionally and/or alternatively comprise one or more polymer based fibers, such as polyester fibers, polyamide fibers, polyurethane fibers, combinations thereof, and/or the like. For example, the polymer fibers may comprise polypropylene fibers, polyethylene fibers, sheathed polymer fibers (e.g., having a polyethylene core and a nylon or polypropylene sheath), and/or the like. As yet another example, the fibrous material may comprise a composite of polymer-based fibers and other fibers (e.g., glass fibers). Such a composite may comprise layers of non-woven and/or woven layers (e.g., a first layer comprising a polymer-based fiber material and a second layer comprising a glass fiber material). 
     Method of Manufacture 
       FIG.  2    is a schematic diagram of a portion of an example carpet tile manufacturing line that may be utilized to construct a carpet tile  100  as discussed herein, and  FIG.  3    is a flow chart of an example method for constructing the carpet tile  100  according to certain embodiments. As discussed herein, the carpet tiles  100  may be manufactured as a portion of a continuous web and later cut into desired tile shapes and sizes. However, it should be understood that carpet tiles  100  may be manufactured according to any of a variety of manufacturing processes, such as a batch process in which each multi-layer carpet tile  100  is constructed as a separate component. 
     In  FIG.  3   , the following blocks represent the following steps of an example method for constructing a carpet tile according to certain embodiments:
         a. Block  301  represents the step of “providing a continuous facecloth web comprising a primary backing having a plurality of face yarns extending therethrough”;   b. Block  302  represents the step of “advancing the facecloth web in an inverted orientation along a web travel path”;   c. Block  303  represents the step of “extruding a continuous sheet of polymer secondary backing material onto a surface of the facecloth web”;   d. Block  304  represents the step of “laying a reinforcing scrim onto an exposed surface of the extruded polymer secondary backing while the extruded polymer secondary backing remains above a softening temperature to form a multi-layer web”;   e. Block  305  represents the step of “advancing the multi-layer web through a nip to partially embed the reinforcing scrim into the extruded polymer secondary backing”; and   f. Block  306  represents the step of “advancing the multi-layer web through one or more chilling rollers to cool the multi-layer web”.       

     As shown in  FIG.  2   , the process begins by providing a facecloth  111  having a plurality of face yarns  105  extending through a primary backing  110  (as indicated at Block  301  of  FIG.  3   ). The facecloth  111  can optionally have a pre-coat layer disposed on a backside of the primary backing  110 . As discussed herein, the topside of the facecloth  111  ultimately forms the top surface of the completed carpet tile  100 . As mentioned, the tufted primary backing  110  is provided as a continuous web, which may be threaded along a web travel path defined by a plurality of rollers (e.g., powered rollers and/or idler rollers). In certain embodiments, the facecloth  111  may have a width between 72-80 inches, although it should be understood that the facecloth  111  may have any width with suitable production equipment. 
     As shown in  FIG.  2   , the facecloth  111  is advanced along the web travel path in an inverted orientation with the backside of the facecloth  111  facing upward, as indicated at Block  302  of  FIG.  3   . The facecloth  111  is advanced past one or more extruder heads  220  configured to extrude a continuous sheet of a resin having an at least substantially uniform thickness onto the backside of the facecloth  111  to form the extruded polymer secondary backing layer  120 , as indicated at Block  303 . In certain embodiments, the extruder head  220  may comprise a single, elongated extrusion die tip opening extending across the entire width of the facecloth  111  such that the resin is extruded as a continuous sheet from the extruder head  220 . Alternatively, the resin may be extruded from a plurality of extruder heads  220  positioned across the width of the web travel path. The plurality of extruder heads may be spaced such that the resin flows together to form an at least substantially continuous extruded polymer secondary backing layer  120  having an at least substantially uniform thickness across the width of the facecloth  111 . 
     The one or more extruder heads  220  may be supplied by one or more extruders (e.g., single screw extruders and/or dual-screw extruders) configured to combine the various components of the resin prior to extrusion to form the extruded polymer secondary backing layer  120 . Once combined, the extruders and one or more extruder heads  220  provide the at least substantially continuous sheet of resin onto the bottom surface of the facecloth  111  at a temperature between about 275-500 degrees Fahrenheit (135 to 260° C.) and at a weight of between about 8-35 ounces per square yard (about 0.271 to about 1.187 kg/m 2 ). In embodiments in which the facecloth  111  comprises a hot melt pre-coat layer  115 , the resin may be applied to the facecloth  111  while the pre-coat layer  115  is sufficiently hot (as may be the case with a hot melt adhesive) so as to retain a tacky characteristic (e.g., while the pre-coat layer material remains above its softening point) to improve the mechanical bond strength between the facecloth  111  and the extruded polymer secondary backing layer  120 . However, it should be understood that the resin need not be applied to the facecloth  111  while a pre-coat layer  115  remains hot in embodiments that do not utilize a hot melt adhesive pre-coat layer  115  (e.g., embodiments without a pre-coat layer  115  and embodiments using an aqueous latex-based pre-coat layer  115 ). 
     After extruding the resin of the extruded polymer secondary backing layer  120  onto the facecloth  111 , the reinforcing scrim layer  130  is laid onto the exposed bottom surface of the extruded polymer secondary backing layer  120  as indicated at Block  304  of  FIG.  3   . The extruded polymer secondary backing layer  120  remains above the resin softening point when the reinforcing scrim layer  130  is laid onto the exposed surface of the extruded polymer secondary backing layer  120 , and the entire multi-layer web (including the facecloth  111 , the extruded polymer secondary backing layer  120 , and the reinforcing scrim layer  130 ) is passed through a nip  250  comprising two rollers positioned on opposite sides of the web travel path to compress the multi-layer web and to provide strong bonds between adjacent layers of the carpet tile  100 . During compression, the extruded polymer secondary backing layer  120  is bonded to the facecloth  111 , and the reinforcing scrim layer  130  is bonded to (e.g., embedded partially within) the extruded polymer secondary backing layer  120  (as indicated at Block  305 ). The reinforcing scrim layer  130  remains partially exposed, such that the reinforcing scrim layer  130  defines at least a portion of the bottom surface of the resulting carpet tile  100 . 
     After the moving multi-layer web passes through the nip  250 , the web passes through one or more chilling rollers  260  to cool and harden the extruded polymer secondary backing layer  120  (shown at Block  306 ). For example, the one or more chilling rollers  260  may be collectively configured to chill the extruded polymer secondary backing layer  120  to approximately room temperature (between about 75-80 degrees Fahrenheit (23.9 to 26.7° C.)). 
     The cooled multi-layer construction may then be passed to a tile cutting mechanism configured to cut the multi-layer web into a plurality of individual carpet tiles or to a take-up roller  270  for storage. For example the web may be passed into a die cutter to cut the material web into market-size carpet tiles  100  (e.g., 18″×18″, 24″×24″, or 36″×36″). Alternatively, the material web may be taken onto a large diameter (e.g., 8-foot diameter) drum where it can be taken to an off-line die cutting station for further processing into carpet tiles  100 . 
     The resulting multi-layer construction (which may be cut into individual carpet tiles  100 ) has an overall thickness that is less than similar carpet tiles having a plurality of backing layers while retaining desirable flatness characteristics of the carpet tile  100 . This permits a larger number of carpet tiles  100  to be stacked in a single carton, on a single pallet, and/or the like. Moreover, the resulting carpet tiles  100  have a lower overall weight than similar carpet tiles having a plurality of backing layers. The decreased volume (due to the decreased thickness) and decreased weight lowers transportation and installation costs associated with carpet tiles  100  according to various embodiments while retaining desirable aesthetic characteristics once installed. 
     EXAMPLE 1 
     One example low-weight carpet tile was manufactured according to the methodology discussed herein. The example carpet tile comprises a facecloth  111  comprising a primary backing layer  110  having a weight of at least approximately 4 ounces per square yard (0.136 kg/m 2 ), and having face yarns  105  tufted therethough at a weight of at least approximately 14 ounces per square yard (0.475 kg/m 2 ). The tufted primary backing is coated with a pre-coat layer  115  having a dry weight of at least approximately 12 ounces per square yard. 
     The facecloth  111  is passed under an extruder head  220  as a part of a continuous web, where the resin of the extruded polymer secondary backing layer  120  is extruded onto a backside of the facecloth  111  (such that the resin is extruded onto the exposed surface of the pre-coat layer  115 ) to form the extruded polymer secondary backing layer  120 . In this example, the extruded polymer secondary backing layer  120  comprises a resin mixture of the components listed in Table 3, heated to a temperature of 325-475 degrees Fahrenheit (162.8 to 246.1° C.) for extrusion. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 3 
               
               
                   
                   
               
               
                   
                 Component 
                 wt % 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                   
                 1-propene, ethylene copolymer 
                 29.80 
               
               
                   
                 Primary antioxidant 
                 0.13 
               
               
                   
                 Secondary antioxidant 
                 0.07 
               
               
                   
                 Ethylene maleic anhydride copolymer 
                 2.00 
               
               
                   
                 Calcium carbonate 
                 67.90 
               
               
                   
                 Carbon black concentrate 
                 0.10 
               
               
                   
                   
               
            
           
         
       
     
     The resin is extruded in a continuous sheet onto the facecloth  111  to create an at least substantially uniform extruded polymer secondary backing layer  120  having an at least substantially uniform thickness. 
     Before the extruded polymer secondary backing layer  120  cools to a temperature below the softening point of the resin, a fiberglass nonwoven reinforcing scrim layer  130  is laid onto the exposed surface of the extruded secondary backing layer  120 , and the entire multi-layer web is passed through a nip  250  and through one or more chilling rollers  260  to embed the reinforcing scrim layer  130  into the extruded polymer secondary backing layer  120  and to cool and harden the extruded polymer secondary backing layer  120 . The cooled web is then cut into individual carpet tiles  100  for evaluation. 
     It was found that the carpet tile  100  provided according to this example construction exhibited exceptional flatness and dimensional stability characteristics, while retaining a total weight of approximately between 40-70 ounces per square yard (1.356 to 2.373 kg/m 2 ), and preferably approximately between 54-57 ounces per square yard (1.831 to 1.933 kg/m 2 ), such as at least approximately 55 ounces per square yard (1.865 kg/m 2 ). 
     EXAMPLE 2 
     One example low-weight carpet tile was manufactured according to the methodology discussed herein. The example carpet tile comprises a facecloth  111  comprising a primary backing layer  110  having a weight of at least approximately 4 ounces per square yard (0.136 kg/m 2 ), and having face yarns  105  tufted therethough at a weight of at least approximately 14 ounces per square yard (0.475 kg/m 2 ). The tufted primary backing is coated with a pre-coat layer  115  having a dry weight of at least approximately 12 ounces per square yard (0.409 kg/m 2 ). 
     The facecloth  111  is passed under an extruder head  220  as a part of a continuous web, where the resin of the extruded polymer secondary backing layer  120  is extruded onto a backside of the facecloth  111  (such that the resin is extruded onto the exposed surface of the pre-coat layer  115 ) to form the extruded polymer secondary backing layer  120 . In this example, the extruded polymer secondary backing layer  120  comprises a resin mixture of the components listed in Table 4, heated to a temperature of about 325-475 degrees Fahrenheit (162.8 to 246.1° C.) for extrusion. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 4 
               
               
                   
                   
               
               
                   
                 Component 
                 wt % 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                   
                 Ethylene-propylene copolymer 
                 19.9 
               
               
                   
                 Propylene homopolymer 
                 2.0 
               
               
                   
                 Tackifier 
                 5.0 
               
               
                   
                 Ethylene maleic anhydride copolymer 
                 3.0 
               
               
                   
                 Calcium carbonate 
                 70 
               
               
                   
                 Carbon black concentrate 
                 0.1 
               
               
                   
                   
               
            
           
         
       
     
     The resin is extruded in a continuous sheet onto the facecloth  111  to create an at least substantially uniform extruded polymer secondary backing layer  120  having an at least substantially uniform thickness. 
     Before the extruded polymer secondary backing layer  120  cools to a temperature below the softening point of the resin, a fiberglass nonwoven reinforcing scrim layer  130  is laid onto the exposed surface of the extruded secondary backing layer  120 , and the entire multi-layer web is passed through a nip  250  and through one or more chilling rollers  260  to embed the reinforcing scrim layer  130  into the extruded polymer secondary backing layer  120  and to cool and harden the extruded polymer secondary backing layer  120 . The cooled web is then cut into individual carpet tiles  100  for evaluation. 
     It was found that the carpet tile  100  provided according to this example construction exhibited exceptional flatness and dimensional stability characteristics, while retaining a total weight of approximately between 40 to 70 ounces per square yard (1.356 to 2.373 kg/m 2 ), and preferably approximately between 54 to 57 ounces per square yard (1.831 to 1.933 kg/m 2 ), such as at least approximately 55 ounces per square yard (1.865 kg/m 2 ). 
     CONCLUSION 
     Many modifications and other embodiments will come to mind to one skilled in the art to which this disclosure pertains having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the disclosure is not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.