Patent Publication Number: US-2015068838-A1

Title: Noise control device

Description:
This application claims the benefit under 35 U.S.C. §119(e) to U.S. Provisional Application No. 61/876,394 filed on Sep. 11, 2013. The application is incorporated herein by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     The present invention relates to a flooring system and, more particularly, to a noise control device for use in a flooring system that reduces noise transmission in a building structure, the device including a porous separation layer that enhances the speed of drying of a poured floor. 
     BACKGROUND 
     Multi-family housing is a large market for quiet living and excessive noise is one of the most litigated issues in apartment and condo construction. Building codes call for specific performance levels for noise and ASTM has separated the noise into airborne and structural causes. In the case of these types of construction applications, a sound control element may be added to the hard surface areas. Hard surfaces include vinyl, tile, wood and similar materials that create a greater level of impact or vibration noise. 
     For many years, the common method of controlling vibration noise in wood and concrete floor/ceiling assemblies has been to pour a floating substrate layer on top of a void creating device commonly referred to as an “entangled net.” The entangled net may be 90% air with more rigid polymer filaments supporting a separation fabric layer that suspends the floating substrate layer from about 0.125 inch to about 1.0 inch above a wood subsurface, creating a void space. The void-limited touching of the two solid materials (subfloor and floating substrate) limits the energy transfer. The limited energy transfer consequently limits the ability of the vibration waves to pass through to the ceiling side of the construction, for example to the apartment or condo unit below. 
     When building these flooring systems, the speed with which the moisture leaves the floating substrate layer is essential to allow for the final finished surface to be applied. Typically the floating substrate layer is made from Portland cement or gypsum cement that is mixed with other materials such as fly ash, retarding agents, plasticizers and other chemicals. These materials act to bond sand particles and other aggregate to form the floating substrate layer. The substrate layer typically is not abrasion resistant and has limited flex strength so that a floor finish must be applied in order to have a floor suitable for foot traffic. 
     It is known in the art to employ a non-breathable product or a breathable product at the underside of the substrate layer. The breathable layer is permeable to air and water vapor, but is impermeable to water. The key in the past has been to limit the ability of liquid water to pass from the poured substrate layer through to the underlying base layer. The conventional non-breathable and breathable products typically have a film or membrane and only allow drying of a poured concrete slab or substrate from the top of the slab. Top side drying can cause curling in Portland cement products and take longer for floor finishes in gypsum based products. Both the breathable and non-breathable products do not enhance the drying time of the poured substrate and the drying time has become too long for construction schedules in many instances. Often, finishes cannot be installed for weeks after the substrate layer has been poured, resulting in significant project delays. 
     SUMMARY 
     In one aspect of the invention, there is provided a noise control flooring system that enhances the speed of drying of an overlying poured floor, the noise control flooring system including a void space creating layer comprising an entangled fiber mat; and a porous separation layer that overlies at least a portion of the void space creating layer; wherein water and vapor from the poured floor overlying the porous separation layer is permitted to pass through the porous substrate layer and into the void space creating layer. The open work member may be an entangled fiber mat. 
     In one embodiment, the porous separation layer includes natural fibers, synthetic fibers or a mixture thereof. 
     In one embodiment, the fibers of the porous separation layer include PET spun laid nonwoven fibers. In another embodiment, the fibers of the porous separation layer include spun bound nonwoven polypropylene. 
     In one embodiment, the porous separation layer has openings that are in the range of about 0.037 mm to about 0.074 mm. 
     In one embodiment, the fibers of the porous separation layer include continuous fibers. In one embodiment, the fibers of the porous separation layer include chopped fibers. 
     The porous separation layer may further include one or more compounds that absorb moisture. 
     In one embodiment, the porous separation layer has applied thereto a nano-technology solution that enhances drying by bonding to the water molecules in the substrate layer. 
     In one embodiment, the entangled fiber mat of the void space creating layer includes a resilient three-dimensional web of extruded polymer monofilaments, the polymer monofilaments being heat welded at junctions to form an open network of tangled monofilament. 
     In one embodiment, the substrate layer of the noise control flooring system includes Portland cement or gypsum cement mixed with other materials selected from fly ash, retarding agents, plasticizers and a combination thereof. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a flooring system including the sound control device in accordance with the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Vibration noise is transmitted via two manners: conduction and air pressure build up. The actual amount of contact between two solid materials works to pass vibration noise easily. If one of the materials is resilient, there is an absorption effect. If the materials have resilience or air space, the thicker the material or air space is, the better the noise absorption will be. The thickness in a resilient, mostly void-containing product works well at controlling vibration noise. 
     In the flooring system of the present invention, a porous separation material is provided at the underside of the poured slab on the sound element. The porous separation material may take the form of a “fabric”, which allows for air movement and is permeable to water. The fabric improves the ability of the slab to dry from the underside by enhancing the water and air flow through the underside and absorbing some moisture from the substrate layer. The absorption of moisture enhances the dry time and allows for the floor finish to be installed more quickly. An important aspect of the fabric is to accomplish this without allowing any powdered fines to pass through into the void space below, which would negatively impact the noise controlling properties of the flooring system. 
     In some of the materials used to form the poured substrate layer, the particle size has been minimized with the addition of fly ash and silica fume materials. Consequently, in the sound control devices used there is a greater need for a fabric separation layer that has a greater sieve size (higher sieve size has a smaller opening), while still helping to enhance drying time. 
     As used herein, the terms “overlies” and “overlying”, when referring to the relationship of one or a first layer relative to another or a second layer, refers to the fact that the first layer partially or completely lies over the second layer. The first layer overlying the second layer may or may not be in contact with the second layer. For example, one or more additional layers may be positioned between the first layer and the second layer. 
     Referring to  FIG. 1 , there is illustrated an exemplary flooring system  10  which includes a solid base  12 . This base is illustrated as being a layer of wood, although it may take other forms, such as a layer of concrete. A compressible layer  14  may overlie at least a portion of the base layer. A mat layer  16 , which takes the form of an open network of entangled fibers, overlies at least a portion of the compressible layer  14 , and creates a void space underlying the substrate layer  20 . A porous separation layer  18  overlies at least a portion of the mat layer  16 . This porous separation layer  18  serves to carry a floating, solid substrate layer thereupon. The substrate layer  20  provides loading for causing the compressible layer  14  to compress into the overlying entangled mat layer  16 . 
     The mat layer  16  is a void creating layer that includes a plurality of intertwined filaments that twist and turn about at random and are bonded at random into sections or contact zones as by heat bonding or other suitable bonding or connection technique. These filaments may be of any suitable strong and mildew-resistant polymeric material. In one embodiment, the filaments are formed in a desired thickness on the order of about 0.25 inch to about 0.75 inch to provide the desired breathability and venting capability for water vapor, air and other gaseous substances. 
     The entangled mat may be constructed in accordance with techniques well known to one of ordinary skill in the art, such as disclosed by, for example, U.S. Pat. Nos. 3,687,759; 3,691,004; and 4,212,692, the contents of all of which are hereby incorporated by reference in their entireties. 
     The filaments of mat  16  may be made from any thermoplastic polymer that provides the desired properties of strength and resilience for the application in which it is used. For example, the monofilaments  22  may be made of a polyolefin (e.g., polyethylene, polypropylene, etc.), polyamide (e.g., Nylon), polyester, polyvinylhalide (e.g., polyvinylchloride (PVC), polyvinylidene chloride, polyvinyltetrafluoride, polyvinyl chlorotrifluoride), polystyrene, polyvinylester (e.g., polyvinyl acetate, etc.) or a mixture of two or more thereof. 
     In one embodiment, the monofilaments  22  have an average diameter in the range of from about 1 mils to about 4 mils, and in one embodiment, from about 2 to about 3 mils. 
     The porous separation layer  18  that overlies a portion of the entangled net layer  16  is constructed of a material that is air and water pervious. The porous separation layer is preferably a non-woven film-like material. It enables a hardenable, cement-type material to be poured over top of the mat layer to harden or cure in place to form substrate layer  20 . This substrate layer  20 , which overlies at least a portion of separation layer  18 , is a floating solid substrate, and is preferably a gypsum cement layer. The porous separation layer  18  prevents fine particles of the overlying substrate layer  20  from passing into the void space creating layer  16 . The porous separation layer  18  may include natural fibers, synthetic fibers or a mixture thereof. The fibers may be chopped fibers or continuous fibers. As used herein, the term “continuous fiber” means a fiber having a fiber length preferably of 70 mm or longer, or 80 mm or longer, or 100 mm or longer. The term “chopped fiber” as used herein means fiber having a fiber length of less than 70 mm, or 5 to 70 mm, or 10 to 50 mm. 
     The separation layer  18  may be constructed a nonwoven fabric made of polyolefin fibers such as polyethylene and polypropylene; polyester fibers such as polyethylene terephthalate (PET), polytrimethylene terephthalate, and polyethylene naphthalate; polyamide fibers such as nylon; rayon fibers and other synthetic fibers. The nonwoven fabrics may be nonwoven fabrics made of single fibers or nonwoven fabrics made of two or more kinds of fibers used in combination. 
     In one embodiment, the separation layer is constructed of continuous hydrophilic fibers. The hydrophilic continuous fibers may be those essentially having hydrophilicity and/or those which are not essentially hydrophilic but have been rendered hydrophilic by hydrophilization treatment. The hydrophilic continuous fibers may include, for example, cellulose acetate fibers or rayon fibers. Cellulose acetate fibers include cellulose triacetate fibers and/or cellulose diacetate fibers. Nylon or acrylic fibers may also be used as the continuous fibers to form the separation layer. 
     The fibers of the porous separation layer are configured to form openings through which water and air can pass, but through which fine particles from the overlying solid substrate layer cannot pass. Table 1 below provides a cross-reference between sieve designations and their related sieve opening sizes. 
     
       
         
           
               
               
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                 U.S. Std. Sieve 
                 Alternative Sieve  
                 Opening 
                 Approximate Opening 
               
               
                 Designation 
                 Designation 
                 mm 
                 Inches 
               
               
                   
               
             
            
               
                 74 μ 
                 No. 200 
                 0.074 
                 0.0029 
               
               
                 63 μ 
                 No. 230 
                 0.063 
                 0.0025 
               
               
                 53 μ 
                 No. 270 
                 0.053 
                 0.0021 
               
               
                 44 μ 
                 No. 325 
                 0.044 
                 0.0017 
               
               
                 37 μ 
                 No. 400 
                 0.037 
                 0.0015 
               
               
                   
               
            
           
         
       
     
     In one embodiment, the fibers of the separation layer  18  are configured such that the openings are about 0.074 mm or smaller, corresponding to a sieve designation of No. 200 or greater. In one embodiment, the fibers of the separation layer  18  are configured to have openings that are in the range of about 0.074 mm to about 0.037 mm, corresponding to a sieve designation of No. 200 to No. 400. 
     In one embodiment, the openings of the porous separation layer correspond to a sieve designation of No. 200, or No. 230, or No. 270, or No. 325, or No. 400. 
     The porous separation layer  18  may be enhanced with one or more compounds that help absorb moisture. In one embodiment, the porous separation layer includes an absorbent polymer held within the fibers or applied to the surface of the separation layer. Examples of absorbent polymers include, for example, sodium polyacrylate, acrylic acid-vinyl alcohol copolymers, crosslinked sodium polyacrylate, starch-acrylic acid graft polymers, isobutylenemaleic anhydride copolymers and saponification products thereof, potassium polyacrylate, and cesium polyacrylate. In one embodiment, the absorbent polymer preferably has the capability of absorbing at least 20 times its weight in water. 
     The porous separation layer  18  may also be sprayed with a nano-technology solution that helps promote drying by bonding to the water molecules in the substrate layer. 
     The separation layer  18  may be constructed of multiple layers. In one embodiment, the separation layer has an upper water-transmissive layer integral with a lower water-transmissive layer. In another embodiment, the separation layer may include an intermediate layer positioned between an upper water-transmissive layer and a lower water- or vapor-transmissive layer, the intermediate layer including a moisture absorbing composition. 
     The optional compressible layer  14  may be manufactured from an ultra lightweight fabric that is “cotton” like in nature. The “cotton” fabric is engineered to compress into the bottom side of the entangled mat  16  creating a small cushion under the filaments and pressing back toward the floating substrate  20 . The “cotton” fabric  14  is typically made from a polymer based filament in a manufacturing process known as carding. In carding, chopped filaments are combed in one direction and then heated and needled to make them combine into a monolithic mat. Needling is the driving and removing of sharp, thin metal (needles) through the filaments to entangle them together. This carding/heating/needling process allows for the material to achieve a designation as a high loft or thick fabric quality. With the thick product, a 100 gram per square meter material can be from about 0.125 inch thick to about 0.626 inch thick, depending on density. Many other products that are carded/heated/needled are engineered to be dense and flat. Consequently, this fabric is highly compressible and can be engineered to almost completely compress under a typical load, such as the load of a floating substrate. 
     The compressible fabric adds very little to the thickness in the application and controls noise in the floor well. It almost completely compresses to the original thickness of the entangled net mat. The profile added is about 0.05 inch and the stability/flex of the material is very good because the dense; entangled net material limits the deflection. Any product that is highly compressible, such as a fabric or foam would be suitable in this application. 
     The floating substrate  20  is typically a gypsum concrete underlayment that is poured onto separation layer  18  and hardens to a compressive strength of approximately 2000 psi (pounds per square inch). The floating substrate is typically between 0.75 inch and 2.0 inches in thickness and overall weighs between 7.5 pounds per square foot and 20 pounds per square foot. 
     In one embodiment, the substrate layer  20  is constructed of Portland cement or gypsum cement that is mixed with other materials, such as fly ash, retarding agents, plasticizers and other chemicals. 
     The floating substrate  20  overlying the separation layer  18  is able to harden, i.e., cure, more quickly with the separation layer described herein. In one embodiment, the separation layer  18  is constructed of fiberglass fabric, allowing for the reinforcement of the floating substrate  20  so that a thinner layer of cement may be used as the floating substrate. With a thinner layer of cement, the drying/curing time of the poured separation layer can be significantly reduced. 
     The sound control device may readily be provided in roll or stacked sheet form for ease in handling and application in a flooring system, and may be cut to size as needed to overlie subfloors or floors of substantially any conceivable size or shape. 
     While the invention has been explained in relation to various embodiments, it is to be understood that various modifications thereof will become apparent to those skilled in the art upon reading this specification. Therefore, it is to be understood that the invention provided herein is intended to cover such modifications as may fall within the scope of the appended claims.