Abstract:
The shelf liner is a multi-layered thermoplastic composite sheet of consistent thickness, with a non-slip bottom side and a decorative top side. A decorative top sheet is fused to a top surface of a substrate layer. The substrate layer comprises a nonwoven fabric or material that is coated on both sides, and can be fully impregnated, with a foamed plasticized polyvinyl chloride. The foamed plasticized polyvinyl chloride coating on the bottom side of the substrate layer gives the shelf liner a non-slip characteristic. An interlayer of polyvinyl chloride plastisol is disposed between the top sheet and the substrate to enhance the fused bonding of the layers. A bottom surface of the substrate layer may be fully or partly covered with a bottom coating to modify the non-slip nature of the shelf liner.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to decorative non-slip liners, and more specifically to a shelf liner that comprises a polyvinyl chloride (PVC) top layer laminated or fused to a non-slip bottom layer via a PVC plastisol interlayer. The non-slip bottom layer consists of a non-woven fabric coated on both sides with foamed plasticized polyvinyl chloride. 
   2. Description of the Related Art 
   In the past, various liners have been made for covering surfaces, such as shelves, drawer interiors, countertops, and the like. The liners are typically both protective and decorative. One common form of liner is simply a plastic film with an adhesive backing coating one side. This simple liner does provide protection and decoration of a surface, but the thin film fails to hide surface flaws or unevenness. The adhesive backed liner cannot be removed for cleaning and, if it is removed, often leaves behind an adhesive residue. 
   Other liners are laminated, including a top protective and decorative layer adhesively bonded to a frictionalized coated pad or matt, such as a scrim or non-woven fabric bearing a frictionalizing coating. These liners often have a rough-textured surface that is reflective of the roughly textured scrim or matt substrate. Additionally, excessive pressure or contact force used during the manufacturing process distorts the surface with a rougher appearance and random thickness variations. These liners are more difficult to clean, and give a different appearance. 
   Additional problems exist with laminated liners. Laminated liners are prone to deformation with age, as chemical migration between different chemicals among the various layers results in differential shrinkage of the layers, causing curling of the liner. Chemical migration, and particularly migration of plasticizers from plasticized coated scrims and plasticized PVC top layers into the adhesive can compromise the strength of the adhesive, causing the laminated liner to delaminate. Chemical migration can also harm the application surface on which the liner is used, leaving behind a film on the application surface after the liner is removed. 
   U.S. Pat. No. 5,707,903, issued on Jan. 13, 1998 to H. Schottenfeld discloses a laminated liner comprising a non-slip pad and a sheet covering. The sheet covering is adhesively attached to the non-slip pad. Additionally, the non-slip pad includes a plurality of open cells extending through the non-slip pad. 
   U.S. Pat. No. 5,863,845, issued on Jan. 26, 1999 to T. Owen, discloses a surface covering that includes a substrate that is non-skid coated. A decorative top sheet is adhered to the substrate with an adhesive. U.S. Pat. No. 5,874,371, issued on Feb. 23, 1999 to T. Owen, discloses a surface covering having a non-skid coated substrate, with a decorative top sheet adhered to the substrate. The bottom surface of the substrate is at least partially coated with a cured polyvinyl-containing resin. 
   U.S. Pat. No. 6,022,617, issued on Feb. 8, 2000 to M. Calkins, discloses a laminated non-slip liner or mat having a layer of a non-woven material with a pattern of a high friction material printed on one side. The printed pattern of relatively high friction material is a matrix of latex or PVC projections. On the other side of the non-woven material layer, a decorative vinyl sheet is affixed by an adhesive. U.S. Pat. No. 6,159,583, issued on Dec. 12, 2000 to M. Calkins, discloses a laminated non-slip liner or mat that is similar to the Calkins &#39;617 patent. 
   U.S. Pat. No. 6,221,796, issued on Apr. 24, 2001 to J. Hawley et al. describes a smooth surfaced foam laminate and a method of making the laminate. The laminate comprises a smooth, continuous, laminated top layer and a discontinuous porous foam bottom layer comprising a loosely woven scrim (cotton fabric) having a rubber or plastic material foamed onto the scrim. The product is usable as a drawer liner, shelf liner or an appliance underlayment. The laminate is distinguishable for requiring a discontinuous porous foam bottom layer comprising rubber or vinyl. U.S. Pat. No. 6,130,174, issued on Oct. 10, 2000 to J. Hawley et al., discloses a smooth surfaced foam laminate and a method of making the laminate similar to the Hawley &#39;796 patent. 
   U.S. Pat. No. 3,360,422, issued on Dec. 26, 1967 to R. Desch, describes a reinforced cellular floor covering comprising a PVC top surface, an open weave scrim, and a cellular PVC backing layer. 
   U.S. Pat. No. 4,828,897, issued on May 9, 1989 to J. Staneluis et al. describes reinforced polymeric composites comprising an outer polymeric skin and an inner polymeric foam core with embedded strands. 
   U.S. Pat. No. 5,854,144 issued on Dec. 29, 1998, to J. Hawley describes a cushioned liner laminate made by adhesively laminating a printed plastic sheet to a top surface of a non-spun polyester fabric having a bottom surface coated with a foam material. 
   U.S. Pat. No. 5,580,651, issued on Dec. 3, 1996 to M. Kerman, discloses an energy absorbing panel having a foam core and a flexible reinforcing layer that may be non-woven. The flexible reinforcing layer is somewhat permeable to allow the foam to pass therethrough. A decorative layer may be attached to a side of the panel. The panel is made from a liquid foamable polyurethane composition molded along with the reinforcing layer. 
   U.S. Patent Application Publication US 2003/0060110, published on Mar. 27, 2003, discloses a method for making a foamed sheet comprising steps of extruding a polymeric meld having two or more classes of expanding agents, allowing the expanding agents to expand, depositing the melt on the surface of a permeable carrier whereby the foamed melt penetrates the surface of the carrier, and allowing the composition to set. 
   U.S. Patent Application Publication US 2003/0104205, published on Jun. 5, 2003, discloses a fabric reinforced closed cell foam composite having a smooth surface that is substantially free of nodular surface irregularities. 
   U.S. Patent Application Publication US 2003/0036323 A1 by R. Aliabadi, published on Feb. 20, 2003, discloses a plastic shelf liner comprising a top layer of a smooth PVC covering a sandwich layer of a polyester fabric between layers of PVC, the covering attached by a heat bonding process. 
   None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed. Thus a shelf liner solving the aforementioned problems is desired. 
   SUMMARY OF THE INVENTION 
   The shelf liner is a multi-layered thermoplastic composite sheet of consistent thickness, with a non-slip bottom side and a decorative top side. A decorative top sheet is fused to a top surface of a substrate layer. The substrate layer comprises a non-woven fabric or material that is coated on both sides, and can be fully impregnated, with a foamed plasticized polyvinyl chloride. An interlayer of polyvinyl chloride plastisol disposed between the top sheet and the substrate enhances the fused bonding of the layers. The plastisol interlayer provides for cohesive, ionic bonding of the three layers. 
   The uniformity of construction of the three similar polyvinyl chloride layers results in a composite thermoplastic material that reduces curl, and resists the de-lamination that is characteristic of adhesively laminated products. 
   Additionally, a bottom coating may be applied to all or to part of the bottom surface of the substrate layer to modify the non-slip nature of the shelf liner. 
   Accordingly, it is a principal object of the invention to provide a shelf liner that is attractive and durable. 
   It is another object of the invention to provide a shelf liner that has a reduced tendency to curl as the product ages. 
   It is a further object of the invention to provide a shelf liner that has a reduced tendency to delaminate as the product ages. 
   Still another object of the invention is to provide a shelf liner wherein the non-slip nature of the shelf liner is modified by a bottom surface coating. 
   It is an object of the invention to provide improved elements and arrangements thereof for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes. 
   These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a plan view of a shelf liner according to the present invention, with a top layer of the shelf liner cut away to show a substrate layer. 
       FIG. 2A  is a section view drawn along lines  2 A- 2 A of  FIG. 1 , showing the layered construction of a shelf liner according to the present invention. 
       FIG. 2B  is a section view similar to  FIG. 2A  showing the layered construction of a first alternate embodiment of a shelf liner according to the present invention. 
       FIG. 2C  is a section view similar to  FIG. 2A  showing the layered construction of a second alternate embodiment of a shelf liner according to the present invention. 
       FIG. 3  is a section of a foamed plasticized polyvinyl chloride substrate layer. 
       FIG. 4  is a schematic diagram of an apparatus for making a shelf liner according to the present invention. 
   

   Similar reference characters denote corresponding features consistently throughout the attached drawings. 
   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The present invention is a shelf liner, designated generally as  10  in the drawings. The shelf liner  10  is formed primarily of layers of plasticized polyvinyl chloride materials, fused together to form a durable liner with a non-skid bottom surface and a decorative and protective top surface. The shelf liner is illustrated in  FIG. 1 , with a top sheet  20  cut-away to show a foamed plasticized polyvinyl chloride substrate layer  40 . 
   Turning now to  FIGS. 2A-2C , the layers of the shelf liner  10  can be seen in greater detail. The substrate layer  40  has a top surface  42  and a bottom surface  44 . The top sheet  20  comprises a thin polyvinyl chloride film  22  having top and bottom surfaces  24 , 26 , and optionally a decorative coating  28 . In use, the shelf liner  10  is placed on an application surface  12 , such as a desk, shelf, countertop, etc., with the substrate bottom surface  44  in contact with the application surface  12 . Because of the somewhat tacky, frictionalized nature of the surfaces of the foamed plasticized polyvinyl chloride material of the substrate layer  40 , the substrate bottom surface  44  has a non-slip characteristic, giving the shelf liner  10  the tendency to resist movement in the plane of the substrate bottom surface  44  when the substrate bottom surface  44  contacts the application surface  12 . 
   The top sheet  20  is fused to the substrate layer  40 . A polyvinyl chloride plastisol interlayer  30  between the top sheet  20  and the substrate layer  40  facilitates the fusing of the layers, improving the bond between the top sheet  20  and the substrate layer  40 . The bonding between the top sheet  20  and the substrate layer  40  is a cohesive, ionic bonding of the layers, rather than adhesive, or adherent bonding. The polyvinyl chloride plastisol interlayer  30  may be modified by the addition of elastic microspheres to vary the resilience and thickness of the shelf liner  10 , the elastic microspheres being admixed in the polyvinyl chloride plastisol. 
   The decorative coating  28  can be disposed on the top surface  24  of the thin polyvinyl chloride film  22 . Alternatively, as shown in  FIG. 2B , the decorative coating can be disposed on the bottom surface  26  of the thin polyvinyl chloride film  22 , the thin polyvinyl chloride film  22  being clear or transparent. The decorative coating  28  may be a solvent based polyvinyl chloride resin ink, a water-based polyester which may be a clear or pigmented ink or coating, a water-based polyurethane which may be a clear or pigmented coating, a UV cured solid clear or pigmented coating, or other suitable material printed or coated onto the thin polyvinyl chloride film  22 . 
   With the decorative coating  28  disposed on the top surface  24  of the thin polyvinyl chloride film  22 , various additives can be included in the material of the decorative coating  28 , such as fine rubber particles or other materials, to alter top surface friction, giving the top as well as the bottom of the shelf liner a non-slip characteristic. 
   As an alternative to the decorative coating  28 , the shelf liner  10  can be decorated by introducing pigments or other additives directly into the interlayer  30 . A clear thin polyvinyl chloride film  22  over the decorated interlayer  30  can be polished, or matte finished to give a range of finish appearances. 
   Additionally, an optional bottom surface coating  50  is shown in  FIG. 2C , disposed on the substrate bottom surface  44 . The bottom surface coating  50  can serve various purposes. The bottom surface coating  50  can uniformly cover the entire substrate bottom surface  44 , acting as a barrier to prevent chemical migration from the polyvinyl chloride compounds of the shelf liner  10  onto the application surface  12 . Alternatively, the bottom surface coating  50  can be patterned, covering parts of the substrate bottom surface  44  and leaving parts exposed. Such a patterning of the bottom surface coating  50  is useful to vary the non-slip characteristic of the shelf liner  10 . The bottom surface coating  50  may be a solvent based polyvinyl chloride resin ink, a water based clear or pigmented polyester ink or coating, a water based clear or pigmented polyurethane clear or pigmented coating, a clear or pigmented UV cured solid coating, or another suitable material. Additionally, fine rubber particles can be admixed with the bottom surface coating  50  material to enhance or alter the non-slip characteristic of the shelf liner  10 . 
   Turning now to  FIG. 3 , the substrate layer  40  comprises a supporting fabric  46  that is coated on each side with foamed, plasticized polyvinyl chloride  48 . The supporting fabric  46  is preferably a nonwoven fabric, although woven and scrim fabrics can also be used. The nonwoven fabric is preferably a polyester spun bond material or a synthetic fibrous material. The foamed plasticized polyvinyl chloride  48  is coated onto each side of the supporting fabric  46 , giving the substrate layer  40  generally smooth surfaces. In addition to coating both sides of the supporting fabric  46 , the supporting fabric  46  may be impregnated with the foamed plasticized polyvinyl chloride  48 , the foamed plasticized polyvinyl chloride  48  filling in voids and interstices between fibers of the supporting fabric  46 . Thus, the substrate layer  40  may be viewed as a solid layer of foamed plasticized polyvinyl chloride  48  with the supporting fabric  46  embedded within. The supporting fabric  46  may be eliminated entirely, leaving the substrate layer  40  consisting of an unsupported single layer of the foamed plasticized polyvinyl chloride  48 . 
   The substrate layer  40  may be modified by the addition of elastic microspheres to the foamed plasticized polyvinyl chloride  48 . The microspheres may be added in varying amounts to vary resilience and thickness of the substrate layer, as well as the non-slip characteristic of the substrate bottom surface  44 . 
   The substrate layer  40  may also be modified by the addition of fine rubber particles to the foamed plasticized polyvinyl chloride  48 . The fine rubber particles may be added in varying amounts to vary the non-slip characteristic of the substrate bottom surface  44 . 
   Because the top sheet  20 , the plastisol interlayer  30 , and the substrate layer  40  are fused together, the shelf liner  10  more closely resembles a continuum of polyvinyl chloride materials rather than discrete layers joined together by an adhesive. This fused construction increases the durability of the shelf liner  10 , reducing deformation, curling and delamination. 
   It can be appreciated that any or all of the polyvinyl chloride materials (including the surface coatings, top sheet, interlayer, and substrate) may also contain additives that are standard in the art, including fillers, pigments, matting agents, UV inhibitors, flame-retardants, biocides and fungicides, and others. 
   The shelf liner  10  can be made according to a process that is schematically depicted in  FIG. 4 . A top sheet supply roll  60  supplies the top sheet  20  material in roll form, delivering the top sheet  20  material at a controlled tension. A substrate layer supply roll  62  supplies the substrate layer  40  material in roll form, delivering the substrate layer  40  material at a controlled tension. Polyvinyl chloride plastisol is applied to the bottom surface of the top sheet  20  by a plastisol coater  64 , forming the plastisol interlayer  30 . The top sheet  20  and the substrate layer  40  are then brought together, the polyvinyl chloride plastisol coated bottom surface of the top sheet  20  in contact with the top surface of the substrate layer  40  to approximate the layers. The layers are then heated by being transported around a large heating roll  66  and then around several small heating rolls  68 . The heating process causes the top sheet  20  and the substrate layer  40 , along with the plastisol interlayer  30 , to become fused together, forming a cohesive, ionically bonded laminate. Unlike conventional processes used for making shelf coverings, it is not required to apply pressure to the laminate to join the layers. Because pressurization is eliminated, the material thickness and surface smoothness are not deformed in the process. 
   Following the fusing of the laminate, a pattern may optionally be embossed by additionally heating the laminate, as shown by infrared heaters  70 , and passing the laminate between embossing rollers  72 . The shelf liner  10  is then cooled by cooling rolls  74 , and collected on a take-up roll  76 . 
   Advantageously, the process does not require a pressure nip, as is required by adhesively bonded laminates. The high pressure applied by the pressure nip causes variations in material thickness and surface smoothness. The shelf liner  10  of the present invention avoids such defects by relying on heat fusion to create cohesive bonding. 
   It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims.