Patent Abstract:
The invention is directed to a sports board ( 15 ). In the preferred embodiment, the sports board comprises a polymer film layer ( 16 ) having an outer surface ( 18 ) and an inner surface ( 19 ), a polyethylene foam layer ( 23 ) having first ( 24 ) and second ( 25 ) outer surfaces, and an extruded adhesive resin layer ( 20 ) bonded to the inner surface of the film layer and the first surface of the foam layer. The adhesive resin may be selected from a group consisting of an ethylene and methyl acrylic copolymer and an anhydride-modified polyolefin, and the hydride-modified polyolefin maybe selected from a group consisting of anhydride-modified ethylene vinyl acetate, adhydride-modified low-density polyethylene and anhydride-modified linear low-density polyethylene. In an alternate embodiment, the sports board ( 102 ) comprises a polyethylene foam layer ( 103 ) having an outer surface ( 104 ) and an inner surface ( 105 ), a non-polyethylene foam layer ( 110 ) having first ( 111 ) and second ( 112 ) outer surfaces, and an extruded adhesive resin layer ( 106 ) bonded to the inner surface of the polyethylene foam layer and the first outer surface of the non-polyethylene foam layer. The non-polyethylene foam layer may comprise expanded polypropylene foam or expanded polystyrene foam.

Full Description:
TECHNICAL FIELD 
     The present invention relates to foam sports boards for recreational use and, more particularly, to a laminated gliding board with improved bonding characteristics. 
     BACKGROUND ART 
     Body boards for riding waves and other recreational sports boards made of foam or other floatational material are known in the prior art. In general, such boards are composed of a number of polyethylene foam and polyethylene film layers that are laminated together by heating the layers and then immediately passing them through a pair of nip rollers. Another conventional process of lamination is to apply heat to the film layer with a heated nip roller on the film side and a normal nip roller on the foam side, where the heated nip roller may be a flat roller. In most cases the surface of the heated nip roller contains an engraved pattern of convex and concave area for better heat transfer. Both of these conventional heating processes cause adhesion by the localized collapse and bonding of the foam cells on the surface of the respective layers. The resulting laminate of the polyethylene foam and polyethylene film is then often heat laminated onto a standard foam core. 
     Because the standard foam core does not have a perfectly flat or planar surface, adhesive contact between the film and foam core is limited to the apexes of the cells on the surface of the foam core. Thus the point of contact is not uniform between the film and foam, but instead the film contacts the points of the outer surface of the core that protrude from the irregular cellular surface of the foam core. 
     Conventional film lamination method typically use micro-cellular high density foam sheets to improve the adhesion between the film and foam core. The micro-cellular foam sheet contains smaller peaks and valleys, with the peaks closer together. The surface area of contact between the sheet and foam is thereby increased. However, this kind of structure is still prone to delamination by mechanical contact forces and by the effect of heat and pressure when in use. 
     While it is known in the prior art that a thin layer of thermal plastic polyethylene film between a polyethylene foam sheet and a polyethylene film can be used to promote lamination, such thin layer of film is generally an unmodified low density polyethylene with limited efficacy. 
     Accordingly, there is need for adhesively bonded sports boards with improved bonding between layers of different polymeric material having different surface contouring and cellular structure. 
     DISCLOSURE OF THE INVENTION 
     With parenthetical reference to the corresponding parts, portions or surfaces of the disclosed embodiment, merely for the purposes of illustration and not by way of limitation, the present invention provides an improved sports board ( 15 ) comprising a polymer film layer ( 16 ) having an outer surface ( 18 ) and an inner surface ( 19 ), a polyethylene foam layer ( 23 ) having first ( 24 ) and second ( 25 ) outer surfaces, and an extruded adhesive resin layer ( 20 ) bonded to the inner surface of the film layer and the first surface of the foam layer. The adhesive resin may be selected from a group consisting of an ethylene and methyl acrylic copolymer and an anhydride-modified polyolefin, and the hydride-modified polyolefin may be selected from a group consisting of anhydride-modified ethylene vinyl acetate, adhydride-modified low-density polyethylene and anhydride-modified linear low-density polyethylene. The polyethylene foam layer may be selected from a group consisting of polyethylene, cross-linked polyethylene, and a copolymer of ethylene vinyl acetate and polyethylene polymeric material. The film layer may be non-opaque and may further comprise a graphic image ( 29 ) printed on the inner surface of the film layer. The board may further comprise a second non-opaque polymer film layer ( 31 ) having an outer surface ( 32 ) and an inner surface ( 33 ), and having a graphic image ( 46 ) imprinted on the inner surface of the second film layer, and the inner surface of the second film layer bonded to the outer surface ( 35 ) of the first film layer ( 34 ). The first film layer may have a thickness of between about 0.01 mm and about 0.15 mm and the second film layer may have a thickness of between about 0.02 mm and about 0.15 mm. The board may further comprise a polyethylene film layer ( 26 ) bonded to the second outer surface ( 25 ) of the foam layer. The board may further comprise a polyethylene foam core ( 62 ) having an upper outer surface ( 63 ) and a lower outer surface ( 64 ), the second outer surface ( 61 ) of the foam layer ( 60 ) bonded to the upper surface ( 63 ) of the foam core ( 62 ). The second outer surface and the upper surface may be heat bonded and the foam layer may have a thickness less than the thickness of the core layer. The board may further comprise a second polymer film layer ( 72 ) having an outer surface ( 74 ) and an inner surface ( 73 ), a second polyethylene foam layer ( 65 ) having first ( 68 ) and second ( 66 ) outer surfaces, a second extruded adhesive resin layer ( 69 ) bonded to the inner surface of the second film layer and the first surface of the second foam layer, and the second surface of the foam layer bonded to the lower outer surface ( 64 ) of the foam core. The board may further comprise a second polymer film layer ( 99 ) having an outer surface ( 101 ) and an inner surface ( 100 ), and a second extruded adhesive resin layer ( 95 ) bonded to the inner surface of the second film layer and the lower outer surface ( 94 ) of the foam core ( 92 ). 
     The present invention also provides an improved sports board comprising a polymer film layer having an outer surface and an inner surface, a non-polyethylene foam layer having first and second outer surfaces, and an extruded adhesive resin layer bonded to the inner surface of the film layer and the first surface of the foam layer. The non-polyethylene foam layer may comprise expanded polypropylene foam or expanded polystyrene foam. 
     The invention also provides an improved sports board ( 102 ) comprising a polyethylene foam layer ( 103 ) having an outer surface ( 104 ) and an inner surface ( 105 ), a non-polyethylene foam layer ( 110 ) having first ( 111 ) and second ( 112 ) outer surfaces, and an extruded adhesive resin layer ( 106 ) bonded to the inner surface of the polyethylene foam layer and the first outer surface of the non-polyethylene foam layer. The non-polyethylene foam layer may comprise expanded polypropylene foam or expanded polystyrene foam. The sports board may further comprise a second polyethylene foam layer ( 116 ) having an outer surface ( 119 ) and an inner surface ( 118 ), and a second extruded adhesive resin layer ( 113 ) bonded to the inner surface of the second polyethylene foam layer and the second outer surface ( 112 ) of the non-polyethylene foam layer ( 110 ). The board may further comprise a polyethylene film layer ( 120 ) having an inner surface ( 121 ) and an outer surface ( 122 ), the inner surface of the polyethylene film layer bonded to the outer surface of the second polyethylene foam layer. 
     Accordingly, the general object of the present invention is to provide an improved sports board in which different polyolefin materials may be used in the layers without a derogation in bonding strength. 
     Another object is to provide an improved sports board which permits the layers to be laminated together using more efficient and less expansive laminating methods. 
     Another object is to provide an improved sports board with improved bond strength and flexibility along the bond line between the laminates. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective and partial sectional view of a first embodiment of the sports board. 
         FIG. 2  is a partial vertical sectional view of the sports board shown in  FIG. 1 . 
         FIG. 3  is a perspective and partial sectional view of a second embodiment of the sports floor. 
         FIG. 4  is a partial vertical sectional view of the sports board shown in  FIG. 3 . 
         FIG. 5  is a perspective and partial sectional view of a third embodiment of the sports board. 
         FIG. 6  is a partial vertical sectional view of the sports board shown in  FIG. 5 . 
         FIG. 7  is a perspective and partial sectional view of a fourth embodiment of the sports board. 
         FIG. 8  is a partial vertical sectional view of the sports board shown in  FIG. 7 . 
         FIG. 9  is a perspective and partial sectional view of a fifth embodiment of the sports board. 
         FIG. 10  is a partial vertical sectional view of the sports board shown in  FIG. 9 . 
         FIG. 11  is a schematic showing the process by which a film layer is bonded to a foam layer with an adhesive resin of the preferred embodiments. 
         FIGS. 12-13  are a schematic showing the process by which a first foam layer is laminated to a second foam layer with an adhesive resin of the preferred embodiments. 
         FIG. 14  is an enlarged sectional view of adhesive resin between two different layers. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     At the outset, it should be clearly understood that like reference numerals are intended to identify the same structural elements, portions or surfaces, consistently throughout the several drawing figures, as such elements, portions or surfaces may be further described or explained by the entire written specification, of which this detailed description is an integral part. Unless otherwise indicated, the drawings are intended to be read (e.g., cross-hatching, arrangement of parts, proportion, degree, etc.) together with the specification, and are to be considered a portion of the entire written description of this invention. As used in the following description, the terms “horizontal”, “vertical”, “left”, “right”, “up” and “down”, as well as adjectival and adverbial derivatives thereof (e.g., “horizontally”, “rightwardly”, “upwardly”, etc.), simply refer to the orientation of the illustrated structure as the particular drawing figure faces the reader. Similarly, the terms “inwardly” and “outwardly” generally refer to the orientation of a surface relative to its axis of elongation, or axis of rotation, as appropriate. 
     Referring now to the drawings and, more particularly, to  FIG. 1  thereof, this invention provides an improved sports board, the first embodiment of which is generally indicated at  15 . As shown in  FIGS. 1-2 , sports board  15  is comprised of four layers laminated together. 
     Top Layer  16  is a graphically-imprinted polymer film. The graphics on layer  16  are imprinted using any of several conventional processes for printing. An example of such a process is corona printing, in which an electrical discharge temporarily alters the surface molecules of the polyethylene film, allowing inks to adhere to the film. Layer  16  has a thickness of between 0.02 mm and 0.15 mm, and preferably a thickness of 0.07 mm. Layer  16  has a density in the range of 0.91 to 0.98 g/cm 3 , and preferably a density of 0.95 g/cm 3 . 
     In the preferred embodiment, layer  20  is an ethylene and methyl acrylic copolymer. Layer  20  has a thickness of between 0.02 and 0.15 mm, and preferably a thickness of 0.07 mm. Layer  20  has a density in the range of 0.90 to 0.98 g/cm 3 , and preferably a density of 0.95 g/cm 3 . The ethylene methyl acrylate copolymer EMAC provided by Eastman Chemical Company, of 100 North Eastman Road, Kingsport, Tenn. 37662, may be employed in the preferred embodiment. It is contemplated that alternative adhesive resins, such as anhydride-modified polyolefin, anhydride-modified ethylene vinyl acetate, anhydride-modified low-density polyethylene, and anhydride-modified linear low-density polyethylene, maybe employed. The Bynel® adhesive resin, provided by Dupont Packaging, of 1007 Market Street, Wilmington, Del. 19898, maybe employed in such an embodiment. 
     Layer  23  is closed-cell polyethylene foam, and acts as the core of board  15 . Core  23  may be beaded type, extruded type or cross-linked polyethylene foam. Core  23  has a thickness of between 0.5 and 2 inches and preferably a thickness of 1 inch. Core  23  has a density in the range of 1.6 to 4 lb/ft 3 , and preferably a density of 2.2 lb/ft 3 . It is contemplated that core  23  may be formed from two or more layers laminated together to provide the appropriate thickness. 
     Layer  26  is polyethylene film. Layer  26  has a thickness of between 0.2 and 1.5 mm, and preferably a thickness of 0.35 mm. Layer  26  has a density in the range of 0.91 to 0.98 g/cm 3 , and preferably a density of 0.95 g/cm 3 . 
     Board  15  is formed in a series of steps. First, layer  26  is heat laminated to the bottom surface  25  of layer  23  using a conventional heat lamination method. The resulting laminate  23 / 26  is then cut and configured to the desired shape. Next, layer  16  is imprinted with the desired graphics using a conventional imprinting procedure. As shown in  FIG. 12 , layer  16  is then fed from a bottom roll  125  and hot resin  20  is extruded and with pressure applied to surface  19  of layer  16  to form a top laminate of layers  16  and  20 . This top laminate  16 / 20  is then turned over and, with the application of heat and pressure, is laminated to the upper surface  24  of the shaped core  23 , thereby forming the fully-laminated board  15 . Layers  16  and  20  are cut and configured to wrap-around and cover the sloped edge of core  23  and the straight edge of layer  26  to form a contoured side to board  15 . 
     As shown in  FIG. 14 , the adhesive resin in this embodiment, as well as the following embodiments, fills in the gaps between the peaks and valleys of each of the opposed surfaces of the two adjacent layers to provide greater contact and better bonding. The extruded resin between two layers of different polymeric material having different surface contouring and cellular structure provides an improved lamination. 
       FIGS. 3-4  show a second embodiment  30 . In this embodiment, board  30  has five laminated layers rather than four. Layer  31  is of the same structure and composition as layer  16  in the first embodiment  15 . Layer  34  is polyethylene film. Layer  34  has a thickness of between 0.01 and 0.15 mm, and preferably a thickness of 0.07 mm. Layer  34  has a density in the range of 0.91 to 0.98 g/cm 3 , and preferably a density of 0.95 g/cm 3 . Layers  37 ,  40  and  43  are of the same structure and composition as layers  20 ,  23  and  26 , respectively, of the first embodiment  15 . 
     Sports board  30  is formed in a series of steps. First, layer  31  is imprinted with the desired graphics using a conventional imprinting procedure. Layer  34  is then laminated to surface  33  of layer  31  to form a laminate film layer  31 / 34 . As shown in  FIG. 11 , laminate film layer  31 / 34  is then fed from a top roll  123  and layer  40  is fed from bottom roll  124 . As laminate layer  31 / 34  and layer  40  are fed from rolls  123  and  124 , respectively, resin  37  is extruded, using a conventional extrusion process, between surface  36  of layer  34  and surface  41  of layer  40  to form a laminated sheet of layers  31 ,  34 ,  37  and  40 . Layer  43  is then heat laminated to surface  42  of laminated sheet  31 / 34 / 37 / 40  using a conventional heat lamination method, thereby forming the fully-laminated sheet  30 . This laminated sheet is then cut and configured to the desired shape. 
       FIGS. 5-6  show a third embodiment  48 . In this embodiment, board  48  has eight laminated layers. Layers  49 ,  52  and  55  are of the same structure and composition as Layers  31 ,  34  and  37 , respectively, of the second embodiment  30 . 
     Layer  59  is polyethylene foam. Layer  59  has a thickness of between 1 and 5 mm, and preferably a thickness of 3 mm. Layer  59  has a density in the range of 4 to 8 lb/ft 3 , and preferably a density of 6 lb/ft 3 . 
     Layer  62  is polyethylene foam. Layer  62  has a thickness of between 0.5 inches and 2 inches, and preferably a thickness of 1 inch. Layer  62  has a density in the range of 1.6 to 4 lb/ft 3 , and preferably a density of 2.2 lb/ft 3 . 
     Layer  65  is of the same structure and composition as layer  59 . 
     Layer  69  is of the same structure and composition as layer  52  and layer  72  is of the same structure and composition as layer  49 . 
     Sports board  48  is formed in a series of steps. First, layer  49  is imprinted with the desired graphics using a conventional imprinting procedure. Layer  52  is then laminated to surface  51  of layer  49  to form a laminate film layer  49 / 52 . As shown in  FIG. 11 , laminate film layer  49 / 52  is then fed from a top roll  123  and layer  59  is fed from bottom roll  124 . As laminate layer  49 / 52  and layer  59  are fed from rolls  123  and  124 , respectively, hot resin  55  is extruded, using a conventional extrusion process, between surface  54  of layer  52  and surface  60  of layer  59  to form a top laminate sheet of layers  49 ,  52 ,  55 , and  59 . Next, again with reference to  FIG. 11 , film layer  72  is then fed from a top roll  123  and layer  65  is fed from bottom roll  124 . As layer  72  and layer  65  are fed from rolls  123  and  124 , respectively, hot resin  69  is extruded, using a conventional extrusion process, between surface  73  of layer  72  and surface  68  of layer  65  to form a bottom laminate sheet of layers  65 ,  69  and  72 . These laminates are then cut and configured to the desired shape and size. Surface  61  of top laminate  59 / 55 / 52 / 49  is then heat-laminated to the top surface  63  of core  62  using a conventional heat laminating method, and surface  66  of bottom laminate  65 / 69 / 72  is then heat-laminated to the bottom surface  64  of core  62  using a conventional heat laminating method, thereby forming the fully-laminated board  48 . 
     As shown in  FIG. 5 , polyethylene foam strips  75  and  76  are then heat laminated to cover the side edges of laminated layers  49 ,  52 ,  55 ,  59 ,  62 ,  65 ,  69  and  72 . Strips  75  and  76  have a thickness of between 2 and 6 mm, and preferably a thickness of 4.5 mm. Strips  75  and  76  have a density in the range of 4 to 8 lb/ft 3 , and preferably a density of 6 lb/ft 3 . 
       FIGS. 7-8  show a fourth embodiment  78 . In this embodiment, board  78  has seven laminated layers. Layers  79 ,  82 ,  85 ,  89  and  92  are of the same structure and composition as layers  49 ,  52 ,  55 ,  59  and  62 , respectively, and layers  95  and  99  are of the same structure and composition as layers  69  and  72 , respectively, of board  48 . However, sports board  78  does not include the foam backing layer  65  of board  48 . The versatility of the adhesive resin allows for the bonding between different foams as well as between different films and foams. 
     Sports board  78  is formed in a series of steps. First, layer  79  is imprinted with the desired graphics using a conventional imprinting procedure. Layer  82  is then laminated to surface  81  of layer  79  to form a laminate film layer  79 / 82 . As shown in  FIG. 11 , laminate film layer  79 / 82  is then fed from a top roll  123  and core  92  is fed from bottom roll  124 . As laminate  79 / 82  and layer  89  are fed from rolls  123  and  124 , respectively, hot resin  85  is extruded, using a conventional extrusion process, between surface  84  of layer  82  and surface  90  of layer  89  to form a top laminate sheet of layers  79 ,  82 ,  85  and  89 . Next, with reference to  FIG. 12 , film layer  99  is fed from a bottom roll  125  and hot resin  95  is extruded and with pressure applied to surface  100  of layer  99  to form a bottom laminate of layers  95  and  99 . This bottom laminate  95 / 99  is then turned over and, with the application of heat and pressure, is laminated to surface  94  of core  92 . The resulting laminate  92 / 95 / 99  is then cut and configured to the desired shape. Surface  91  of top laminate  79 / 82 / 85 / 89  is then heat-laminated to the top surface  93  of the shaped core  92  using a conventional heat laminating method, thereby forming the fully-laminated board  78 . Layers  79 ,  82 , 85  and  89  are cut and configured to wrap-around and cover the sloped edge of layer  92  and the straight edges of layers  95  and  99  to form a contoured side to board  78 . This embodiment does not include the separate side strips  75  and  76  of the third embodiment  48 . 
       FIGS. 9-10  show a fifth embodiment  102 . In this embodiment, board  102  has six laminated layers. 
     Layer  103  is polyethylene foam. Layer  103  has a thickness of between 2 and 8 mm, and preferably a thickness of 4.5 mm. Layer  103  has a density in the range of 4 to 10 lb/ft 3 , and preferably a density of 7 lb/ft 3 . 
     Layer  106  is of the same structure and composition as layer  55  in the fourth embodiment. 
     Layer  110  is non-polyethylene foam. In the preferred embodiment, layer  110  is polystyrene foam. However, it is contemplated that other types of foam may be used, such as polypropylene foam. Layer  110  has a thickness of between 1 and 2.5 inches, and preferably a thickness of 2.125 inches. In the preferred embodiment, layer  110  is polystyrene foam and has a density in the range of 1.0 to 2.5 lb/ft 3 , and preferably a density of 1.5 lb/ft 3 . If polypropylene foam is used, layer  110  would have a density in the range of 1.5 to 3 lb/ft 3 , and preferably a density of 1.9 lb/ft 3 . 
     Layer  113  is of the same structure and composition as layer  106 . 
     Layer  116  is polyethylene foam. Layer  116  has a thickness of between 1 and 5 mm, and preferably a thickness of 3 mm. Layer  116  has a density in the range of 4 to 8 lb/ft 3 , and preferably a density of 6 lb/ft 3 . 
     Layer  120  is polyethylene film. Layer  120  has a thickness of between 0.2 and 1.5 mm, and preferably a thickness of 0.35 mm. Layer  120  has a density in the range of 0.91 to 0.98 g/cm 3 , and preferably a density of 0.95 g/cm 3 . 
     Sports board  102  is formed in a series of steps. First, polyethylene foam layer  116  is heat laminated to film layer  120  using conventional heat laminating methods. As shown in  FIGS. 12 and 13 , laminate  116 / 120  is then unrolled from a bottom roll  125  and hot resin  113  is extruded and with pressure applied to surface  118  of layer  116  to form a bottom laminate of layers  113 ,  116  and  120 . This bottom laminate  113 / 116 / 120  is then turned over and, with the application of heat and pressure, is laminated to the bottom surface  112  of a pre-formed core  110 , as shown in  FIG. 13 . Next, again with reference to  FIG. 12 , polyethylene foam layer  103  is unrolled from a bottom roll  125  and hot resin  106  is extruded and with pressure applied to surface  105  of layer  103  to form a top laminate of layers  103  and  106 . This top laminate  103 / 106  is then heat laminated to surface  111  of core layer  110  as shown in  FIG. 13 , thereby forming the fully-laminated board  102 . The top laminate  103 / 106  is cut and configured to wrap-around and cover the inclined edges of core layer  110 . This embodiment also includes two separate side strips  123  and  124  of polyethylene foam which are applied with hot resin, using the same method as the application of resin  106  to layer  103 , and then heat laminated to cover the lower inclined side edges of core layer  110 . Side strips  123  and  124  have a thickness of between 1 and 5 mm, and preferably a thickness of 3 mm. Side strips  123  and  124  have a density in the range of 4 to 8 lb/ft 3 , and preferably a density of 6 lb/ft 3 . 
     The present invention contemplates that many changes and modifications may be made. Therefore, while the presently-preferred forms of the improved sports board have been shown and described, and several modifications thereof discussed, persons skilled in this art will readily appreciate that various additional changes and modifications may be made without departing from the spirit of the invention, as defined and differentiated by the following claims.

Technology Classification (CPC): 1