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United States Patent Application	20090071097
Kind Code	A1
McDonald; Raiford	March 19, 2009

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Claims

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1. A wall covering system comprising:a substrate having a decorative face surface and a back surface;a layer of a first polymer on said back surface of said substrate; anda vertical wall having a surface, said wall surface having a second polymer layer thereon, such that when said first and second polymer layers are brought into contact, said first layer on said substrate and said second layer on said wall removably retain said substrate on said wall without the use of an adhesive.

2. A method of applying a wall covering to a vertical wall having a surface to be covered, said method comprising:forming a layer of a second polymer on said surface of said vertical wall; andapplying to said wall surface a substrate having a back surface, said back surface comprising a layer of a first polymer, said substrate being applied to said wall surface such that said second polymer layer on said wall surface and said first polymer layer on said substrate contact each other and removably retain said substrate on said wall surface without the use of an adhesive.

3. The method of claim 2, wherein said second polymer layer on said wall surface is selected from flexible thermoplastics, elastomers, rubbers and mixtures thereof.

4. The method of claim 2, wherein said second polymer layer on said wall surface is selected from ethylene vinyl alcohols, polyamides (Nylon 6), Nylon 6/rubber modified, polybutylene, low density polyethylene, high density polyethylene, low density polyethylene/ethyl vinyl acetate copolymers, low density polyethylene/ethyl ethylene acetate copolymers, polypropylene, polyvinylidenechloride copolymer, thermoplastic polyurethanes, krayton, rubber modified polystyrene, silicone rubber, styrene-butadiene, acrylics and copolymers thereof, natural rubber, and mixtures thereof.

5. The method of claim 2, wherein said second polymer layer on said wall surface is an acrylic.

6. The method of claim 2, wherein said first polymer layer on said substrate is selected from flexible thermoplastics, elastomers, rubbers and mixtures thereof.

7. The method of claim 2, wherein said first polymer layer on said substrate is selected from ethylene vinyl alcohols, polyamides (Nylon 6), Nylon 6/rubber modified, polybutylene, low density polyethylene, high density polyethylene, low density polyethylene/ethyl vinyl acetate copolymers, low density polyethylene/ethyl ethylene acetate copolymers, polypropylene, polyvinylidenechloride copolymer, thermoplastic polyurethanes, krayton, rubber modified polystyrene, silicone rubber, styrene-butadiene, acrylics and copolymers thereof, natural rubber, and mixtures thereof.

8. The method of claim 2, wherein said first polymer layer on said substrate is an acrylic copolymer.

9. The method of claim 2, wherein said first polymer layer on said substrate has a glass transition temperature of about -15 to about +20.degree. C.

10. The method of claim 2, wherein said first polymer layer on said substrate has a glass transition temperature of about -6.degree. C.

11. The method of claim 2, wherein said second polymer layer on said wall surface has a glass transition temperature of about +4 to about +37.degree. C.

12. The method of claim 2, wherein said second polymer layer on said wall surface has a glass transition temperature of about +10 to about +18.degree. C.

13. The method of claim 2, wherein said wall surface comprises gypsum board, fiber board, plywood, oriented strand board, hard wood, or plaster.

14. The method of claim 2, wherein said second polymer layer is formed on said wall surface by spraying, painting, rolling or spreading.

15. The method of claim 2 further comprising applying pressure to said substrate to press said first polymer layer on said substrate and said second polymer layer on said wall surface into contact.

16. The method of claim 2, wherein said first polymer layer on said substrate is substantially smooth.

17. The method of claim 2, wherein said second polymer layer on said wall surface is substantially smooth.

18. A method of applying a decorative wall covering to a vertical wall comprising gypsum board and having a surface to be covered, said method comprising:applying a second layer of a polymer on said surface of said gypsum board;allowing said second polymer layer on said surface of said gypsum board to dry;applying to said gypsum board surface a wall covering material having a decorative face surface and a back surface, said back surface comprising a layer of a first polymer, said wall covering material being applied to said gypsum board surface such that said second polymer layer on said surface of said gypsum board and said first polymer layer on said wall covering contact each other and removably retain said wall covering material on said gypsum board surface without the use of an adhesive.

19. A method comprising applying a wall covering having a back surface comprising a first polymer layer to a wall surface comprising a second polymer layer such that said first and second polymer layers are in mutual contact whereby said wall covering is removably retained on said vertical wall without the use of an adhesive, wherein said first polymer layer has a glass transition temperature of about -15 to about +20.degree. C. and said second polymer layer has a glass transition temperature of about +4 to about +37.degree. C.

20. The method of claim 19, wherein said second polymer layer on said substrate has a glass transition temperature of about +10 to about +18.degree. C.

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Description

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CROSS-REFERENCE TO RELATED APPLICATIONS

[0001]The present application claims the benefit of provisional patent application Ser. No. 60/973,652 filed Sep. 19, 2007.

FIELD OF THE INVENTION

[0002]The present invention generally relates to wall covering products. More particularly, this invention relates to wall covering products that do not require an adhesive to apply them to and retain them on a wall surface. The present invention also relates to methods of making and using these wall covering products.

BACKGROUND OF THE INVENTION

[0003]Wall covering materials, such as wallpaper, are frequently applied to vertical wall surfaces to provide a decorative surface. Wall paper is a paper product including a decorative design or pattern printed on a surface of the paper. Other types of wall coverings include grasscloth, fabrics (paper backed and acrylic backed), paper backed foils, fabric backed foils, vinyl or acrylic coated paper, nonwovens, Kraft paper, burlap, cork and the like.

[0004]The vertical wall surface to be covered is typically either a gypsum board or plaster surface and may be painted or un-painted. Initial preparation of the surface to be covered optionally includes applying a sizing material or a primer/sealer material, which may be a dilute form of wall covering adhesive. Wallpaper or wall covering material is typically applied with an adhesive or paste. Wall covering adhesives or pastes are typically based on cellulose, starch, wheat, vinyl or acrylic material, depending on the amount of adhesion necessary. The wall covering adhesive or paste is typically applied to the back surface (i.e., the surface opposite the decorative surface) of the wall covering material and allowed to penetrate into the wall covering over a period of time (usually a few minutes), which process is known as booking. The wall covering is then applied to the surface of the wall to be covered by placing the surface of the wall covering including the adhesive or paste into contact with the surface of the wall to be covered. The wall covering is then positioned to match the pattern of adjacent strips of wall covering material (if necessary), smoothed, trimmed and the adhesive or paste is allowed to dry or cure in place so as to secure the wall covering to the wall surface.

[0005]Removal of the wall covering from the wall often results in damage to the wall surface. When the underlying wall material is gypsum board, the paper facing of the gypsum board can be torn, gouged or delaminated during wall covering removal due to the tenacity, strength and/or amount of penetration of the wall covering adhesive. The wall covering removal process is typically highly labor intensive and time consuming. Although chemical treatments or steaming are available to facilitate the process, wall covering removal is often so difficult that people merely paint over the existing wall covering or apply another layer of wall covering on top of the existing wall covering in order to avoid to wall covering removal task.

[0006]It would, therefore, be desirable to provide a wall covering system that can easily be applied and removed from wall surfaces of different construction. It would also be desirable to provide a wall covering system that can be removed from a wall surface without damaging the wall surface to which it is applied. It would also be desirable to provide a wall covering system that does not require the use of an adhesive or paste to apply the wall covering material to a vertical wall surface.

SUMMARY OF THE INVENTION

[0007]The present invention satisfies the foregoing needs by providing a wall covering system comprising a substrate having a decorative face surface and a back surface. On the back surface of the substrate is a layer of a first polymer. On a vertical wall having a surface to be covered is a layer of a second polymer. The first and second

[0008]Water is added to the foregoing formulation in an amount sufficient to provide a total solids content of about 40% to 48%; preferably about 40%. Viscosity should be about 75 to 200 cps (Brookfield RVF #3 spindle @ 20 RPM); pH should be about 7.5 to 8.5.

[0009]The foregoing formulation produces a coating on a wall covering, such as wall paper, that has sufficient attraction for the coating described above in Example 1 to attached the wall covering to the gypsum board, in accordance with the present invention.

[0010]It should be understood, of course, that the foregoing relates only to certain disclosed embodiments of the present invention and that numerous modifications or alterations may be made therein without departing from the spirit and scope of the invention as set forth in the appended claims. polymers have a mutual attraction for each other and provide an adhesion to each other that can be broken and re-adhered multiple times without damaging the polymers, the substrate or the wall. When the first and second polymer layers on the back surface of the substrate and the surface of the wall are brought into contact, the first layer on the substrate and the second layer on the wall removably retain the substrate on the wall without the use of an adhesive.

[0011]In an alternate embodiment, the present invention comprises a method of applying a wall covering to a vertical wall having a surface to be covered. The method comprises forming a layer of a second polymer on the surface of the vertical wall. A substrate having a back surface comprising a layer of a first polymer is applied to the wall surface such that the polymer layer on the wall surface and the polymer layer on the substrate contact each other and removably retain the substrate on the wall surface without the use of an adhesive.

[0012]In another alternate embodiment, the present invention comprises a method of applying a decorative wall covering to a vertical wall comprising gypsum board and having a surface to be covered. The method comprises applying a layer of a second polymer to the surface of the gypsum board. This polymer layer is permitted to dry. A wall covering material has a decorative face surface and a back surface. The back surface of the wall covering material comprises a layer of a first polymer. The wall covering material is applied to the gypsum board surface such that the first polymer layer and the second polymer layer contact each other and removably retain the wall covering material on the gypsum board surface without the use of an adhesive.

[0013]Accordingly, it is an object of the present invention to provide an improved wall covering system.

[0014]Another object of the present invention is to provide a wall covering system wherein the wall covering can be relatively easily applied to wall surfaces of different materials.

[0015]Still another object of the present invention is to provide a wall covering system wherein the wall covering can be relatively easily removed from the wall surface.

[0016]Still another object of the present invention is to provide a wall covering system that does not use adhesive or paste systems to retain the wall covering material on a wall surface.

[0017]These and other objects, features and advantages of the present invention will become apparent upon a review of the following detailed description of the disclosed embodiments and the appended drawing and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018]FIG. 1 is a side cross-sectional view of a disclosed embodiment of a wall covering product in accordance with the present invention.

[0019]FIG. 2 is a side cross-sectional view of an alternate disclosed embodiment of a wall covering product in accordance with the present invention.

[0020]FIG. 3 is a side cross-sectional view of a disclosed embodiment of a wall having a surface to be covered.

[0021]FIG. 4 is a side cross-sectional view of the wall covering product of FIG. 1 applied to the wall of FIG. 3.

[0022]FIG. 5 is a side schematic view of a disclosed embodiment of an apparatus for manufacturing a wall covering product in according with the present invention.

DETAILED DESCRIPTION OF THE DISCLOSED EMBODIMENTS

[0023]The present invention relates to a wall covering system. With reference to the drawing in which like numbers indicate like elements throughout the several view, it will be seen that there is disclosed a decorative wall covering 10 (FIG. 1) comprising a substrate 12 which can be made of paper, a fabric (woven, nonwoven or knitted), a plastic or other materials typically used in the wallpaper and wall covering art. The substrate 12 has a face surface 14 and a back surface 16. The face surface 14 includes a decorative layer 18, which can be a printed design, a synthetic or natural fabric (woven, nonwoven or knitted), grass, foil or the like. The back surface 16 includes a first polymer layer 20. The first polymer layer 20 is a skid resistant polymer or a polymer having a glass transition temperature of about -15 to about +20.degree. C.; preferably, about -6.degree. C. The first polymer layer 20 is preferably an acrylic polymer or copolymer having the foregoing properties which gives a clear, tacky coating, which is preferably protected by a release film or paper prior to use.

[0024]The wall covering 10 can be applied to a vertical wall 22 (FIG. 2). The wall 22 typically comprises a wall board 24 supported by a plurality of wooden or metal wall studs 26. The wall board 24 is typically attached to the wall studs 26 by nails, screws, or an adhesive (not shown). The wall board 24 can be any material typically used in the construction of residential or commercial walls including, but not limited to, gypsum board (also known as dry wall or sheet rock), fiber board, hard wood, plywood, oriented strand board or plaster. The wall board 24 includes an outward-facing surface 28 which is to be covered with the wall covering 10. Disposed on the surface 28 of the wall board 24 is a second polymer layer 30. The second polymer layer 30 is a skid resistant polymer or a polymer having a glass transition temperature of about +4 to about +37.degree. C.; preferably, about +10 to about +18.degree. C. The second polymer layer 30 is preferably an acrylic polymer or copolymer having the foregoing properties which dries to a clear, hard, shiny continuous film on the surface of the wall board 24. This film exhibits excellent light, heat, and water resistance.

[0025]The first polymer layer 20 on the substrate 12 and the second polymer layer 30 on the vertical wall 22 can be made from the same material or from different materials. The polymer layers 20, 30 have a physical attraction or affinity to each other that resists relative lateral movement and separation after contact between such polymer layers, but permits the layers to be pulled apart with the application of sufficient manual force. Thus, the first polymer layer 20 of the wall covering 10 has a physical attraction or affinity to the polymer layer 30 of the wall 22 and resists relative lateral movement and separation so as to retain the wall covering on the vertical wall after contact between the layers, but permits the wall covering to be pulled away from the wall with the application of sufficient force.

[0026]The polymer layers can be in the form of a film or a coating. If the skid resistant polymer layer is a film, it can be attached to the wall covering or wall board by any suitable means, including, but not limited to, adhesive lamination or thermal lamination. The term film is used herein in its conventional sense or meaning. Typically, films have a thickness of about 0.0005 to about 0.012 inches. If the polymer layer is a coating, it can be applied to the wall covering or wall by any suitable means, including, but not limited to, spraying, painting (brushing or rolling), dipping, or spreading. If the polymer layer is a coating, it can be applied at the rate of about 0.5 to about 4 ounces per square yard (dry weight); preferably about 1 ounce per square yard (dry weight).

[0027]An example of a polymer films useful in the present invention is cling-type plastic wrap used to wrap and preserve food items. In terms of stress-strain properties, plastics can be divided into four types: (1) flexible thermoplastics, capable of large plastic deformations; (2) rigid thermoplastics; (3) rigid thermosets; and (4) elastomers or rubbers. From this definition of plastics, it is contemplated that the flexible thermoplastics and the elastomers or rubbers are suitable for use in the disclosed embodiment of the present invention. Specific polymers that are useful in the disclosed embodiment include, but are not limited to, ethylene vinyl alcohols, polyamides (Nylon 6), Nylon 6/rubber modified, polybutylenes, low density polyethylenes, high density polyethylenes, low density polyethylene/ethyl vinyl acetate copolymers, low density polyethylene/ethyl ethylene acetate copolymers, polypropylenes, polyvinylidenechloride copolymers, thermoplastic polyurethanes, krayton, rubber modified polystyrenes, silicone rubbers, styrene-butadienes, acrylics and copolymers thereof, natural rubber, latex and mixtures thereof. It is especially preferred that these polymers have a glass transition temperature of about +4 to about +37.degree. C.; preferably, about +10 to about +18.degree. C.

[0028]Some typical properties of polymers suitable for use as the polymer layers of the disclosed embodiment of the present invention are set forth in Table 1 below.

TABLE-US-00001 TABLE 1 Specific Melting Percent Polymer Gravity Point .degree. C. Modulus M-PSI Hardness Elongation Ethylene vinyl- 1.2-1.20 142-191 75-80.sup.a 180-330 alcohol Polyamide, Nylon 6 1.12-1.14 210-220 100-102.sup.b 100-300 Nylon 6/Rubber 1.07-1.17 210-220 50.sup.b 150-270 Modified Polybutylene 0.909-0.915 118-130 45.sup.a 160-350 LDPE 0.910-0.925 98-115 14-38 44-50.sup.a 100-650 HDPE 0.947-0.965 125-135 85-160 63-65.sup.a 170-800 LDPE/EVA 0.922-0.943 103-110 17-45.sup.a 200-700 LDPE/EEA 0.930-0.941 17-45.sup. 700-750 Polypropylene 0.900-0.910 160-175 1.4-1.7 80-90.sup.c 100-600 Polyvinylidene 1.65-1.72 160-172 200-600 55.sup.c 350-400 chloride copolymer TPU 1.12-1.24 75-137 75.sup.d-70.sup.a 60-550 a = Shore D b = Rockwell-M c = Rockwell-D d = Shore A

[0029]The polymer layer on the wall covering is smooth or substantially smooth. As used herein the term substantially smooth is meant that when the polymer layer of the wall covering is placed in contact with the polymer layer on the wall surface, the polymer layer is sufficiently smooth such that there is sufficient mutual contact between the two polymer layers to provide sufficient attraction therebetween to retain the wall covering on the vertical wall surface without the use of an adhesive (as used herein the term "adhesive" means traditional wall covering adhesives or pastes. Preferably, there is sufficient attraction between the two polymer layers that the edges of the wall covering will remain flat and will be retained on the wall; i.e., the edges do not bend or curl outwardly from the wall surface. There is also sufficient attraction that the wall covering can be removed from the wall surface and reapplied thereto and substantially the same attraction exists between the two coatings. Preferably, such removal and reapplication of the wall covering can be done repeatedly without significant degradation of the attraction between the two polymer layers; i.e., sufficient attraction remains such that the wall covering is retained on the wall surface. Although it is believed that the removal and reapplication can be performed indefinitely, it is especially preferred that the removal and reapplication of the wall covering can be done at least ten times without significant degradation of the attraction between the two polymer layers.

[0030]In order for the polymer layer on the wall covering to be substantially smooth, the back surface of the wall covering must be reasonably smooth; i. e., sufficiently smooth such that when the polymer layer is applied to the back surface of the wall covering, the polymer layer is smooth or substantially smooth. However, if the back surface of the wall covering is not sufficiently smooth, a coating or layer of a polymer, preferably a layer of a polymeric foam, can be applied to the back of the wall covering, such that the back surface of the wall covering is rendered sufficiently smooth.

[0031]With reference to FIG. 4, there is disclosed an alternate disclosed embodiment of the wall covering useful in the present invention. The wall covering 10' comprises a substrate 12'. The substrate 12' has a face surface 14' and a back surface 16'. The face surface 14' includes a decorative layer 18'. In this embodiment, the back surface 16' of the substrate 12' is uneven, such as might be encountered if the substrate is a woven fabric to provide dimensional stability to the wall covering 10'. If the first polymer layer were applied directly to the back surface 16' of the substrate 12', the resulting layer would not be sufficiently smooth to provide sufficient mutual contact with the second polymer layer 30 on the wall board 24. If such is the case, it is desirable to apply an intermediate layer 32 between the back surface 16' of the substrate 12' and the first polymer layer 20' of the wall covering 10'. The intermediate layer 32 can be a polymer elastomer or a polymer foam. The intermediate layer 32 should be sufficiently thick such that the unevenness of the back surface 16' of the substrate 12' is sufficiently reduced so that when the first polymer layer 20' is applied, it results in a substantially smooth first polymer layer. Thus, the thickness and/or amount of the intermediate layer 32 will depend on the amount of unevenness of the back surface 16' of the substrate 12'. Generally speaking, the intermediate foam layer can have a density of about 1.5 to about 40 pounds per cubic foot and a thickness of about 1/64 of an inch to about 1 inch. The intermediate layer can be made from any compatible material including natural materials, such as natural rubber latex, or synthetic materials, including, but not limited to, styrene butadiene and polyurethane.

[0032]The foam layer and plastic film (first polymer layer) may be prepared separately and then laminated together using any conventional method, such as thermal lamination or lamination with adhesives. However, it is preferred that the foam layer be prepared in situ on the plastic film or the film may be formed in situ on the foam in a continuous process.

[0033]The extruded plastic film may be positioned on a moving endless belt where it is transported to a foam deposition station. At the foam deposition station, a quantity of a frothed foam-forming composition is deposited on the side of the plastic film opposite the belt. The foam/film composite is passed under a doctor bar that shapes the foam on the film into a uniform layer of a desired thickness. The foam layer on the film is then cured or is permitted to cure depending on the particular type of foam-forming composition that is used, such as by passing the foam/film composite through a forced air oven at a desired temperature. The film and attached cured foam layer may then be stripped from the belt and rolled into a take-up roll.

[0034]Alternately, a quantity of a frothed foam-forming composition may be deposited on a non-stick, moving endless belt. The foam on the moving belt is then passed under a doctor bar that shapes the foam on the belt into a uniform layer of a desired thickness. A layer of plastic film is then applied to the surface of the foam. The foam/film composite is then cured or is permitted to cure depending on the particular type of foam-forming composition that is used, such as by passing the foam/film composite through a forced air oven at a desired temperature. The film and attached cured foam layer may then be stripped from the belt and rolled into a take-up roll.

[0035]In an alternate embodiment, a quantity of a frothed foam-forming composition may be deposited on a non-stick, moving endless belt. The foam on the moving belt is then passed under a doctor bar that shapes the foam on the belt into a uniform layer of a desired thickness. The foam layer on the moving belt is then cured or is permitted to cure depending on the particular type of foam-forming composition that is used, such as by passing the foam layer on the moving belt through a forced air oven at a desired temperature. A quantity of a liquid film-forming composition can then be applied to the surface of the foam layer opposite the belt, such as by dip coating or roller coating. The film-forming coating on the foam surface is then cured or is permitted to cure depending on the particular type of film-forming composition that is used, such as by passing the film-forming coating on the foam surface through a forced air oven at a desired temperature.

[0036]The foam may also be formed in situ on the back surface of the wall covering. The wall covering may be positioned on a moving endless belt such that the decorative side is adjacent the belt. The wall covering is then transported on the belt to a foam deposition station. At the foam deposition station, a quantity of a frothed foam-forming composition is deposited on the back side of the wall covering; i.e., the side opposite the decorative side. An extruded film is then brought into contact with the uncured foam on the back side of the wall covering. The wall covering/foam/film laminate is then passed under a gauge roller such that the foam on the wall covering is formed into a uniform layer of a desired thickness. The wall covering/foam/film laminate is then cured or is permitted to cure depending on the particular type of foam-forming composition that is used, such as by passing the laminate through a forced air oven at a desired temperature. The wall covering/foam/film laminate may then be stripped from the belt and rolled into a take-up roll.

[0037]Alternately, the film may be adhesively secured to the back surface of the wall covering. The wall covering may be positioned on a moving endless belt such that the decorative side is adjacent the belt. The wall covering may then be moved to an adhesive deposition station. At the adhesive deposition station, a quantity of an adhesive is applied to the back surface of the wall covering. The adhesive may be applied in any manner that provides an even coating on the back surface of the wall covering, such as dip coating or roller coating. An extruded plastic film is then brought into contact with the uncured adhesive-coated back surface of the wall covering. The wall covering and film laminate is then passed under a press roller which pushes the film into intimate contact with the back surface of the wall covering. The wall covering/adhesive/film laminate is then cured or is permitted to cure depending on the particular type of adhesive composition that is used, such as by passing the laminate through a forced air oven at a desired temperature. The wall covering/adhesive/film laminate may then be stripped from the belt and rolled into a take-up roll.

[0038]Alternately, the film and foam may be formed and then attached to the back surface of the wall covering. With reference to FIG. 5, it will be seen that there is disclosed an apparatus 100 for preparing a disclosed embodiment of the present invention. The apparatus 100 comprises an endless belt 112 extending along an endless path over the rollers 114, 116, 118 and 120 of which some are driven by an electric motor (not shown), the idler rollers 122 and 124, the belt guide rollers 126, 128 and 130 and the belt tensioning rollers 132, 134 and 136 (FIG. 5). The belt 112 moves in a continuous loop in the direction shown by the arrows (FIG. 5). The speed of the belt 112 is variably controllable to adjust to varying manufacturing needs. Generally, for producing a wall covering, belt speeds that are useful in the present invention are preferably about 8 to about 80 feet per minute, especially about 10 to about 60 feet per minute. Other speeds can also be used depending on the product that is being manufactured.

[0039]From the drive roller 116, the belt 112, which preferably is constructed from fiberglass coated with a low coefficient of friction coating, such as Teflon.RTM. (polytetrafluoroethylene), passes around the drive rollers 118 and 120. The belt 112 is delivered by the idler rollers 122 and 124 and then to a film coating station 138 comprising an applicator roller 140 partially submerged in a liquid skid resistant polymer elastomeric composition mixture 142 in a trough 144. The mixture preferably comprises an ethylene vinyl acetate latex, surfactants, a thickener, a flame retardant and an internal lubricant. A doctor blade 146 is positioned downstream of the applicator roller 140 to control the thickness of the film as it is coated onto the belt 112 by wiping off any excess which then flows down the blade back into the trough 144. The film 148 on the coated belt 112 is then dried in a circulating hot air dryer 150. The dried elastomeric film has a thickness of about 0.0005 inches to about 0.002 inches, preferably about 0.001 inch and a weight per square yard of about 0.4 ounces to about 2 ounces, preferably about 0.9 ounces. Alternately, the elastomeric film 148 can comprise a layer of an olefin material, such as polyethylene or polypropylene, or a layer of polyvinyl chloride or rubber lattices, such as natural rubber or synthetic styrene-butadiene rubber (SBR) latex. In addition, the elastomeric film can be extruded onto the belt rather than formed in situ.

[0040]From the drier 150, the belt 112 with the dried elastomeric film 148 thereon is then passed over the belt guide rollers 126, 128 and 130 to properly position the belt in preparation for polyurethane deposition. Then, the belt 112 is passed over the belt tensioning rollers 132, 134 and 136 and back to the roller 114.

[0041]Downstream from the roller 114 is a frothed polyurethane deposition station 154. The polyurethane deposition station 154 includes a suitable commercial frothing machine 156 having its discharge hose 58 extending above the belt 112. Polyurethane frothing machines are well known in the art, such as an Oakes mechanical frother available from E.T. Oakes Corp. The frothing machine 156 produces a mechanically frothed uncured foam of polyurethane reactants.

[0042]The polyurethane reactants comprise at least one polyol, at least one isocyanate, a surfactant and optionally a catalyst are continuously charged into the frothing machine 156. The polyurethane reactants are preferably frothed to a density of about 16 to about 30 pounds per cubic foot; especially, about 18 to about 30 pounds per cubic foot; specifically, about 18 pounds per cubic foot. A polyurethane formulation suitable for use in the present invention is disclosed in U.S. Pat. No. 6,790,872 (the disclosure of which is incorporated herein by reference).

[0043]In order to assure a uniform lay down of the polyurethane reactants onto the belt 112, the end of the hose 158 is positioned about 0.25 inch to about 6 inches, preferably about 2.0 inches above the belt. Additionally, the centerline of the hose 158 is positioned about 1 inch to about 10 inches, preferably about 3 inches, upstream from a spreading device or doctor blade 160.

[0044]The frothed polyurethane reactants are deposited on the film-coated belt 112 in an amount such that they form a puddle or rolling bank 162 in front of the doctor blade 160. The deposited frothed polyurethane reactant mixture is then smoothed and spread into a reactive layer 163 of uniform thickness by the doctor blade 160 positioned at a desired distance above the belt 112. The frothed polyurethane reactant mixture is preferably formed into a layer of about 0.07 to about 0.5 inches thick; especially, about 0.125 to about 0.5 inches thick.

[0045]Simultaneously with the deposition of the frothed polyurethane reactants onto the conveyor belt 112, a wall covering material 164 of conventional construction, is dispensed from a supply roll 166. The wall covering 164 includes a backing fabric 168 and a decorative layer 170. The wall covering 164 is then fed under a marriage bar 172 to tension and marry the wall covering 164 to the layer 163 of frothed uncured polyurethane reactants.

[0046]After the wall covering 164 is married with the uncured polyurethane reactants, the foam-backed wall covering is heated to affect the desired cure of the polyurethane foam in a curing section 190. This is accomplished by passing the wall covering 164/foam/film laminate on the belt 112 over the cure heaters 192 which raise the temperature of the foam sufficiently to cure the foam, such as about 150.degree. to 350.degree. F.; preferably about 250.degree. to 300.degree. F.

[0047]Finally, the wall covering 164, together with the attached cellular polyurethane layer and polymer film, is stripped from the belt 112 at the exit 194, fed around the roll 196 and rolled into a take-up roll 198.

[0048]Use of the invention will now be considered. The typical wall surface in most residential and commercial buildings is gypsum board. In order to apply the wall covering in accordance with the disclosed embodiment of the present invention, the surface of the gypsum board is first coated with the second polymer. Application of the polymer to the gypsum board can be made by any suitable method, such as by brushing, rolling or spraying. The second polymer is then permitted to dry and/or cure.

[0049]After the second polymer on the gypsum board has dried, the wall covering 10 is applied to the gypsum board 24 such that the first polymer layer 20 of the wall covering contacts the second polymer layer 30 on the gypsum board (see FIG. 3). If the wall covering 10 is in the form of elongate strips, as is customary for wallpaper and wall covering material, it is often necessary to adjust the position of the wall covering on the wall surface after it is applied. However, when the first polymer layer 20 contacts the second polymer layer 30, it is difficult to adjust the position of the layers relative to one another; i.e., slide the wall covering on the wall surface. However, if a small amount of water is sprayed on either the first polymer layer 20 or the second polymer layer 30, or both, the thin film of water interferes with the contact of the polymer layers and permits the wall covering 10 to be adjusted on the wall 22 surface. Then, after the water evaporates, the first polymer layer 20 and the second polymer layer 30 come into intimate contact and hold the wall covering in place without the use of an adhesive.

[0050]It also may be desirable to press the wall covering 10 into contact with the second polymer layer 30 to insure intimate contact of the polymer layers 20, 30. This can be done, for example, by running a rubber roller over the decorative surface 18 of the wall covering 10 after it is applied to the wall 22. Alternately, a wallpaper brush can be used to press the wall covering 10 against the second polymer layer 30.

[0051]The wall covering 10 can be trimmed to the appropriate size before it is applied to the wall 22. Or, the wall covering 10 can be trimmed using a utility knife in the same manner that conventional wall coverings are trimmed by those skilled in the art. The trimmed portion of the wall covering 10 can then be peeled from the surface of the wall board 24 since the polymer layers 20, 30 do not form a permanent bond.

[0052]Removal of the wall covering 10 from the wall board 24 is relatively simple. A sharp object, such as the tip of a knife or a fingernail, is slid under the edge of the wall covering 10 and lifted from the second polymer layer 30 on the surface of the wall 22. Then, the wall covering 10 is grasped with the fingers and peeled from the second polymer layer 30 on wall 22 surface. Since no adhesive is present, the wall covering can usually be peeled from the wall 22 without tearing of the wall covering and without damage to the second polymer layer 30 or to the wall board 24. Since neither the wall board 24 nor the second polymer layer 30 are damaged during removal of the wall covering 10, a new wall covering can be applied immediately without any further preparation of the wall 22 surface. The new wall covering 22 can be applied to the wall 22 in the same manner as described above.

[0053]The following examples are illustrative of certain disclosed embodiments of the present invention.

EXAMPLE 1

[0054]The formulation in Table 2 below is useful for applying to sheetrock or wall board (second polymer) in accordance with the present invention.

TABLE-US-00002 TABLE 2 Ingredient Trade name Supplier Amount (by weight) Polyvinyl acetate Duroset National Starch 30.00 homopolymer emulsion Acrylic polymer emulsion Rhoplex Rohm & Haas 70.00 T.sub.g +28 to +34 .degree. C. Coalescent agent Dowanol Dow Chemical 7.00 pH adjusting agent potassium Monsanto; Callaway 0.20 hydroxide Chemical Thickening agent (sodium Paragum Parachem as required for polyacrylate) viscosity adjustment

[0055]Water is added to the foregoing formulation in an amount sufficient to provide a total solids content of about 40% to 43%; preferably, about 42%. Viscosity should be about 500 to 700 cps (Brookfield RVF #3 spindle @ 20 RPM); pH should be about 7.5 to 8.5.

[0056]The foregoing formulation produces a smooth, shiny coating on gypsum board, or other wall boards, that provides a suitable surface for attaching the wall covering in accordance with the present invention.

EXAMPLE 2

[0057]The formulation in Table 3 below is useful for applying to wall covering (first polymer) in accordance with the present invention.

TABLE-US-00003 TABLE 3 Ingredient Trade name Supplier Amount (by weight) Acrylic polymer emulsion Rhoplex Rohm & Haas 100.00 T.sub.g -15 to +20 .degree. C. Penetrating surfactant Mykon Omnova 3.50 pH adjusting agent potassium Monsanto; Callaway as required hydroxide Chemical Thickening agent (sodium Paragum Parachem as required for polyacrylate) viscosity adjustment

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