Abstract:
The present invention provides a floor covering having a surface that forms a boundary with an ambient environment, and that includes a structure comprising an effective quantity of electrically polarizable, pyroelectric particles disposed substantially below that surface. A method for generating negative ions is also provided that includes positioning a flooring cover within a building, where the floor covering includes a surface that forms a boundary with the ambient environment of the building. The floor covering comprises an effective quantity of pyroelectrically polarizable material disposed no more than one millimeter from the surface, so that when a person or thing travels across that surface so as to frictionally heat the pyroelectrically polarizable material, negative ions are generated. Such generation of negative ions neutralizes or reduces odor, airborne bacteria, mold spores, pollens, and other harmful particles in the air.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is a continuation-in-part of, and claims priority from, co-pending patent application Ser. No. 11/036,941, filed Jan. 14, 2005, and entitled Ionic Or Ion Generating Floor Covering And Method For Embedding Ion Particles Within A Floor Covering. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     Ambient air is composed of molecules of gases that can often become positively or negatively charged due to static electricity discharges and/or other natural causes. High concentrations of negatively charged molecules, often referred to as “negative ions” or “minus ions”, are often found near waterfalls, country meadows, beaches and mountains. High concentrations of positively charged molecules, often referred to as “positive ions”, are often found in polluted areas, such as, cities, office buildings, factories and other urban settings.  
         [0003]     Scientists now recognize that the level of concentration of negative ions in the ambient air we breathe can be beneficial. For example, high levels of negative ions in the ambient air often have the beneficial effect of removing normally positively charged harmful particulate contaminants, such as, pollens, mold spores, smoke, dust particles, airborne germs, and bacteria, from the air. These pollutants are often removed from air through collisions between negative ions and the pollutants. Collisions between negative ions and airborne pollutants causes the negative ions to lose their mobility and effectiveness. These collisions cause the airborne pollutants to slow down and settle out of the ambient air. The use of negatively charged ions to purify air in a room is well known, as a shown in U.S. Pat. Nos. 3,973,927 and 6,610,127.  
         [0004]     Air inside buildings tends to become stale and unpleasant to breathe as a result of, in part, the depletion of the negative ion content in the air. Various conventional air ionizers have been developed to counteract the depletion of negative ions and also to purify air by causing the precipitation of particulate contaminants out of the air, and onto nearby surfaces. Such conventional air ionizers typically include pointed electrodes that are connected to high voltage supplies to produce intense electrical fields adjacent to the pointed electrodes. Neutral gas molecules in the vicinity of these intense electrical fields are transformed to positive or negative ions, depending on the polarity of the high voltages on the electrodes. Electrostatic repulsions from the similarly charged electrodes, along with air blowers, disperse the negatively charged ions throughout the room to cause precipitation of particulate contaminants from the air and to promote the concomitant beneficial physiological effects.  
         [0005]     This technology of has been introduced into ordinary household and healthcare goods, such as, hairbrushes, tooth brushes, footwear, cosmetics, air-conditioners, clothing, water-treatment systems, toilets, hair dryers and other electrical goods. Examples of ion implantation in a plastic material are disclosed in U.S. Pat. Nos. 4,526,832, and 4,743,493. In U.S. Pat. No. 6,964,808, issued to Shintome, a wall material is disclosed that is formed by adding a predetermined amount of binding agent and water to volcanic ash sediment comprised of mineral silicates including at least silicic acid and aluminum oxide, kneading them together, and applying them to a wall surface. Through a natural reaction of positive ions included within the mineral silicate and moisture from the atmosphere, charge is exchanged, and negatively charged ions are generated at the wall&#39;s surface. Humidity control apparatus are also suggested as a negatively charged ion generation system through adjustment of the amount of moisture included within the air so as to control the ion exchanging rate. In one embodiment, volcanic ash sediment is employed that includes titanium oxide, which reacts with hydrogen or oxygen generating active oxygen species or oxygen free radicals. The generation of active oxygen species, provides an air filter.  
         [0006]     There is a need in the art for a flooring material that exhibits all of the foregoing benefits associated with negative ion generation, but without the need for high voltage or humidity control, and that allows for the generation of efficacious quantities of negative ions as a by-product of normal use.  
       SUMMARY OF THE INVENTION  
       [0007]     The present invention provides a floor covering having a surface that forms a boundary with an ambient environment, and that includes a structure comprising an effective quantity of electrically polarizable, pyroelectric particles disposed substantially below that surface. In some embodiments, a portion of effective quantity of the electrically polarizable particles is exposed to said ambient environment. In other embodiments, a wear layer is positioned atop the surface so as to locate the exposed portion of the electrically polarizable particles no more than one millimeter from the surface.  
         [0008]     In one preferred embodiment, a floor covering is provided that includes a surface that forms a boundary with air and a layer of tourmaline particles that are disposed substantially below the surface.  
         [0009]     A method for generating negative ions is provided that includes positioning a flooring cover within a building, where the floor covering includes a surface that forms a boundary with the ambient environment of the building. The floor covering comprises an effective quantity of pyroelectrically polarizable material disposed no more than one millimeter from the surface, so that when a person or thing travels across that surface so as to frictionally heat the pyroelectrically polarizable material, negative ions are generated.  
         [0010]     In another method, a person or thing traverses a flooring cover so as to frictionally engage a surface that forms a boundary with the ambient environment so that frictional heating of a pyroelectrically polarizable material located substantially below the surface causes negative ions to be generated by the floor covering. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]     These and other features and advantages of the present invention will be more fully disclosed in, or rendered obvious by, the following detailed description of the preferred embodiments of the invention, which are to be considered together with the accompanying drawings wherein like numbers refer to like parts and further wherein:  
         [0012]      FIG. 1  is a broken-away, perspective view of a person walking across a floor covering formed in accordance with the present invention;  
         [0013]      FIG. 2  is a broken-away, perspective view of a person walking across a floor covering, similar to that of  FIG. 1 , but including the movement of a rolling object across the floor covering;  
         [0014]      FIG. 3  is a partially broken-away, partially cross-sectioned and partially phantomed perspective view of a floor tile formed in accordance with the present invention;  
         [0015]      FIG. 4  is a cross-sectional view of the floor tile shown in  FIG. 3 , as taken along lines  4 - 4  in  FIG. 3 ;  
         [0016]      FIG. 5  is an enlarged view of a portion of the floor tile shown in  FIG. 4 ;  
         [0017]      FIG. 6  is a broken-away cross-sectional view of one embodiment of floor tile formed in accordance with the present invention;  
         [0018]      FIG. 7  is a broken-away cross-sectional view of one embodiment of floor tile formed in accordance with the present invention;  
         [0019]      FIG. 8  is a broken-away cross-sectional view of a further alternative embodiment of floor tile formed in accordance with the present invention;  
         [0020]      FIG. 9  is a broken-away cross-sectional view of one embodiment of floor tile formed in accordance with the present invention;  
         [0021]      FIG. 10  is a broken-away cross-sectional view of one embodiment of floor tile formed in accordance with the present invention;  
         [0022]      FIG. 11  is a broken-away cross-sectional view of one embodiment of floor tile formed in accordance with the present invention;  
         [0023]      FIG. 12  is a partially broken-away, partially cross-sectioned and partially phantomed perspective view of a floor tile formed in accordance with an alternative embodiment of the present invention, including a decorative image;  
         [0024]      FIG. 13  is a broken-away cross-sectional view of a floor tile formed in accordance with the present invention, as taken along lines  13 - 13  in  FIG. 12 ; and  
         [0025]      FIG. 14  is a broken-away cross-sectional view of similar to that shown in  FIGS. 12 and 13 . 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0026]     This description of preferred embodiments is intended to be read in connection with the accompanying drawings, which are to be considered part of the entire written description of this invention. The drawing figures are not necessarily to scale and certain features of the invention may be shown exaggerated in scale or in somewhat schematic form in the interest of clarity and conciseness. In the description, relative terms such as “horizontal,” “vertical,” “up,” “down,” “top” and “bottom” as well as derivatives thereof (e.g., “horizontally,” “downwardly,” “upwardly,” etc.) should be construed to refer to the orientation as then described or as shown in the drawing figure under discussion. These relative terms are for convenience of description and normally are not intended to require a particular orientation. Terms including “inwardly” versus “outwardly,” “longitudinal” versus “lateral” and the like are to be interpreted relative to one another or relative to an axis of elongation, or an axis or center of rotation, as appropriate. Terms concerning attachments, coupling and the like, such as “connected” and “interconnected,” refer to a relationship wherein structures are secured or attached to one another either directly or indirectly through intervening structures, as well as both movable or rigid attachments or relationships, unless expressly described otherwise. The term “operatively connected” is such an attachment, coupling or connection that allows the pertinent structures to operate as intended by virtue of that relationship. In the claims, means-plus-function clauses, if used, are intended to cover the structures described, suggested, or rendered obvious by the written description or drawings for performing the recited function, including not only structural equivalents but also equivalent structures.  
         [0027]     The present invention provides a floor covering  5  that comprises air-purifying properties by having the capability of generating negative ions  7  continuously into the air without the use of electrodes or electricity. As a person  9  walks on floor covering  5 , highly mobile negative ions  7  are moved and circulated within the ambient environment. Floor covering  5  may be provided in the form of one or more tiles, sheets, planks or strip floor tiles, sheets or planks, including floor tiles, sheets, and planks or sections of varying sizes and shapes and surface types including those made from polyvinyl chloride, rubber, linoleum, polymeric resins, reinforced resins, vinyl composite, or other resilient materials, carpet, stones, ceramic, metals, glass, textiles, wood, composites thereof in desired combinations, veneers thereof in desired combinations, and laminates thereof in desired combinations.  
         [0028]     In one embodiment of the present invention floor covering  5  that takes the form of a tile  10  having a base layer  12 , an aesthetic layer  14 , and a mixture of naturally ionized minerals or ceramic ingredients  16  that continually release negatively ionized particles or negative ions  7  into the ambient environment. Base layer  12  includes a substantially planar top surface  20  and a bottom surface  22 , and often comprises a flat sheet formed from a single layer including a mixture of polymer binder, fillers, stabilizers, and optional plasticizers, processing aids, pigment, etc. For example, plasticizer is required when the polymer is polyvinyl chloride (PVC) homo polymer. Of course, the composition of base  12  may include more than one polymer, e.g., PVC/vinyl acetate copolymer. Acceptable polymer binders may include PVC homo &amp; copolymers, polyolefin homo &amp; copolymers including metallocene polyolefins, acrylic polymers, polyesters, or other thermoplastic polymer materials. Other acceptable polymer binders may include thermoset polymers, such as, rubber, linoleum, epoxy, acrylic, polyesters, etc., but the process for making base layer  12  may vary depending upon the choice of polymer binder. Top surface  20  may form a boundary with the ambient environment or may be covered by additional layers.  
         [0029]     If base  12  is to be monochrome, the composition is mixed within a Banbury® or conventional extruder (of the type that is well known in the art) and formed by feeding the heated mix through at least one calendar, thereby producing a consolidated sheet that can be cut into discrete floor tiles  10 , if desired. Optional planishing or finishing rolls may be present in the process. If a multicolored single layered base  12  is desired, i.e., so that base layer  12  also provides aesthetic value to the floor covering, different colored sheets are made as above, but these are each subsequently ground into particles, chips, or cut into other shapes. In one embodiment, these particles or chips are then blended together, heat processed through the calendar operation to produce a consolidated single multicolored base layer  12 . Typically, this calendaring process produces visuals with directional veining or distortion of the shapes. One example of this type structure is a resilient flooring, vinyl composition tile, as described by Federal Specification SS-T-312b, Type IV, Composition I. Flat bed pressing processes, among others known in the art, may be used that produce non-directional visuals. These can produce solid layers with patterned regions, for example squares, chips, etc. Of course, base layer  12  may comprise other known flooring substrate structures, including but not limited to felts, glass mats, scrims, fabrics, filled and unfilled solid layers, filled and unfilled foam layers, or combinations thereof.  
         [0030]     Aesthetic layer  14  is similar in composition to base layer  12  inasmuch as it often comprises a flat, substantially planar sheet formed from a single, heat processed layer including a mixture of polymer binder, fillers, stabilizers, and optional plasticizers, processing aids, pigment, etc., and including a top surface  26  and a bottom surface  28 . Top surface  26  may form a boundary with the ambient environment or may be covered by one or more additional layers. One or more pigments, in the form of particulates or chips, are often added to the polymer binder of aesthetic layer  14 , in predetermined patterns, colors, textures, and quantities, to impart a predetermined color or pattern of colors to top surface  26 . Aesthetic layer  14  is adhered to base layer  12  such that top surface  20  of base layer  12  is securely engaged with or bonded to bottom surface  28  of aesthetic layer  14  to form a finished tile  10 . In some embodiments, aesthetic layer  14  may comprises a printed layer  50  ( FIGS. 12-14 ) having a colored design or pattern that is visible from top surface  26 . The printed layer may be formed by rotogravure, screen, flexographic, intaglio, ink jet, or other printing processes that may also be used separately or at the same time to deposit polarizable material  16  so as to form a portion of printed layer  50 . Printed layer  50  may form a boundary with the ambient environment or may be covered by one or more additional layers.  
         [0031]     The present invention provides a floor covering  5  that includes polarizable materials  16 , i.e., an effective quantity of electrically polarizable particles, that may be embedded within a shallow region (relative to top surface  26  of aesthetic layer  14 ) so as to naturally release negative ions  7  into the ambient environment at room temperature. A preferred depth for positioning a layer  30  of polarizable materials  16  for adequate negative ion generation and cost-effective production would be no more than one millimeter from a surface that forms a boundary with the ambient environment, e.g., top surface  26  of aesthetic layer  14  ( FIGS. 8, 9 ,  10 , and  11 ). Positioning layer  30  of polarizable materials  16  so that a portion of some of the polarizable particles are exposed to the ambient environment( FIGS. 5, 5 , and  10 ) with the remainder of the polarizable particles being located substantially below the surface, may also provide adequate results. This construction allows for direct frictional heating of the pyroelectrically polarizable particles through contact with the sole  27  of a foot, shoe  29 , boot, or surface  31  of a wheel  33  rolling across the outer most surface or wear surface  35  of floor covering  5 .  
         [0032]     Polarizable material  16  may include any mineral, compound, or mixture of materials that exhibit a “pyroelectric effect”, i.e., that exhibit a spontaneous change in polarization in response to changes in temperature in either direction, which leads to the build-up of “static electric charge” on the surface of the material and its surroundings. It will be understood that frictional heating of polarizable materials  16 , via foot or vehicle traffic moving across outer most surface or a wear surface  35  of urethane, drives the electrical polarization of polarizable materials  16  and thereby the production of negative ions  7 . In some embodiments of the invention from forty to one hundred and forty negative ion counts per cubic centimeter of ambient air are generated upon application of frictional forces to wear surface  35  resulting from movement across floor covering  5  at a rate of about one hundred and fifty centimeters per minute, at a pressure of about nine hundred and ninety-five mPa. The time period necessary to achieve an equilibrium state is about five minutes, with a grounding condition including a surface resistance of floor covering  5  of less than about 1 megaohm, at sixty percent humidity and twenty-five degrees Celsius. These results have been detected using a Negative Ion Measurement System (ITC-403A-based measurement system) such as the type provided by Industrial Technology Research Institute, Materials Research Laboratories, Taiwan.  
         [0033]     Some examples of the types of minerals that may be used as polarizable material  16  in connection with the present invention include, but are not limited to tourmaline, serpentine and zeolite as well as other polarizable compounds including those comprising, Ti, Na, Zn, and Si. Often a mixture of tourmaline, serpentine and other minerals may be used together to generate a preferred quantity of negative ions  8 . Polarizable material  16  may also include forms of volcanic ash and pottery grade ceramic ingredients that are known to facilitate the generation of negative ions  7  in sufficient quantities to have effect. Tourmaline is often preferred for use in the present invention as it is known exhibit a strong pyroelectric effect that facilitates the generation of negative ions  7  in efficacious quantities, e.g., in the range from about one hundred particles per cubic centimeter to six hundred and fifty particles per cubic centimeter. Polarizable materials  16  are typically refined into particles that are size in the range from about 0.25 to about 0.35 microns, with about 0.30 microns on average being preferred.  
         [0034]     Referring to  FIG. 6 , one embodiment of the present invention positions a layer  40  of polarizable material  16  adjacent to top surface  26  of aesthetic layer  14  so that portions of polarizable material  16  are exposed at top surface  26  which forms a boundary with the ambient environment. In this embodiment, polarizable material  16 may be embedded in top surface  26  ( FIG. 6 ) or applied to it ( FIG. 7 ) so that the individual particles of polarizable material  16  are at least partially exposed at top surface  26 . This embodiment would allow the use of polarizable material  16  having particle sizes in the range from about 0.6 to 0.8 millimeters. Of course, polarizable materials  16  may be mixed-in with aesthetic layer  14  so as to be distributed through out its thickness. In one embodiment, adequate results are obtained with an effective quantity of about ten percent by weight per polymer system, ( FIGS. 8 and 9 ).  
         [0035]     In a further embodiment of the invention, a relatively thin protective coating  42 , having a wear surface  35  is sometimes, but not always applied to top surface  26  as a covering for polarizable materials  16  so as to reduce wear of the system. Protective coating  42  may form a boundary with the ambient environment or may be covered by one or more additional layers. The types of coatings that may be used to protect and retain layer  40  include, but are not limited to finishes and polishes, urethanes, acrylics, urethane acrylates, polyester acrylates, rubbers, thermoplastic rubbers, thermoplastic ethylene and other coatings well known in the art, e.g., alumina and alumina compounds. In one embodiment, a solvent base, thermal cured urethane coating containing an acrylic polyol is used with adequate results. Two coats of polyurethane coating  42  are often applied to floor covering  5  to ensure more durability to the product at a thickness of from 0.15 mm to 0.3 mm. Hot press lamination is often used with floor covering  5  that includes protective coating  42  to increase the ion generation density of final product. Protective coating  42  may also comprise a preformed film, such as, clear pvc, surlyn, urethane that is applied to top surface  26 . Of course, a layer  40  of polarizable materials  16  may be disposed within coating  42  ( FIG. 11 ) or, polarizable materials  16  may be mixed-in with coating  42  so as to be distributed through out its thickness with adequate results ( FIG. 5 ). In this embodiment, an even distribution through thorough mixing of polarizable materials  16  helps to reduce discoloration of the material. Additionally, it will be understood that when polarizable materials  16  are located adjacent to or on a bottom surface of coating  42  ( FIG. 10 ) they may be reverse coated or mixed in a printing ink (if a decorative printed layer  50  is employed as a layer directly beneath the coating  42 , as shown in  FIGS. 12-14 .  
         [0036]     It is to be understood that the present invention is by no means limited only to the particular constructions herein disclosed and shown in the drawings, but also comprises any modifications or equivalents within the scope of the claims.