Abstract:
A sport board for snow sledding or surf body boarding comprises a multi-layered laminated composite foam core coupled with stiffening elements for mechanical strengthening of the board. The composite foam core comprises laminates of polyolefin foam base and stiffening elements composed of substantially polymer foam and has substantial higher compressive strength and flexural strength than the foam base. A front section may be made of the same blank material as the low density polyolefin foam base and is bonded to the front end of the foam core complex to give a full frontal flexibility for a higher directional control by the rider and improved shock absorbing property. Polyethylene foam sheets wrap the foam core complex subassembly and head section for sled integrity and graphic film finishes the sled top, the bottom is also finished with a polyethylene sheet for slickness.

Description:
[0001]     This application is a continuation in part of application Ser. No. 11/368,106 filed May 3, 2006 by inventor Wah Kan Cheung entitled Sports Board with Integral Laminated Stiffening Element, the disclosure of which is incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     A. Field of the Invention  
         [0003]     The present invention relates generally to sports boards, and more particularly to polyethylene based composite foam boards for gliding on snow or water having a stiffening element coupled to the core for mechanical strengthening of the board. The present invention relates to stiffening elements composed of substantially polymer foam that may be placed in selected positions to selectively increase rigidity to selected portions of a foam board. With controlled placement of stiffening element(s), the foam board can be adapted to have higher stiffness in a first portion and greater flexibility in a second portion of the board.  
         [0004]     B. Description of the Prior Art  
         [0005]     Body boards and snow gliding boards are typically made of a polyolefin foam that imparts some flexibility and resiliency during gliding. Polyethylene foam sports boards have recently become very popular, in particular as snow sleds, bodyboards and other kinds of gliding boards. However, one drawback in using a polyethylene foam sports board is that it does not have the desirable stiffness against the flex of the foam board caused by the weight of the rider and this impairs the maneuverability of the sports board. For example, in the application of snow sled, such deformation of the board will result in the foam sled submerging below the snow surface and thereby reduce the sliding speed and directional stability when carrying a rider sliding down a snow-covered slope. It is obviously more desirable to have a foam sled or a bodyboard having higher flexural strength.  
         [0006]     Some prior arts apply a polyethylene foam core of higher stiffness by increasing the thickness or density of foam core, or by laminating a thick polymer film outside the foam board. Yet this increases the weight of foam board degrading desirable performance in its applications as a snow sled or bodyboard. It would be desirable to provide a method to make a polyethylene foam sports board at a lower density and less weight but with sufficient stiffness to support a rider to perform the intended function on the sports board. Also desirable is to provide a method to make a foam sports board that has high flexural strength at relatively low cost.  
         [0007]     Expanded polystyrene (EPS) or polystyrene foam core has been used to produce foam sports boards due to its lightweight and rigid properties. However, there are some drawbacks associated with a polystyrene foam core. For example, for a snow sled, a polystyrene foam core does not provide the same degree of comfort in terms of cushioning and shock absorption properties compared to a polyethylene foam core. In addition, the polystyrene foam is poor in elastic recovery under even minor impact forces, and may form undesirable indentations such as in the front portion of a snow sled. It may be desirable to develop a foam core that has the structural stiffness advantages of a polystyrene foam core in the main body and the desirable resilient and shock absorption properties of polyethylene foam in the top and front portion of the board.  
         [0008]     One typical method of strengthening bodyboard is to insert one or more cylindrical rods, know as stringers, into holes drilled parallel to the longitudinal axis of the board from the tail end toward the nose end. A stringer system would generally include a fiberglass or graphite rod that is centrally inserted and adhesively secured in the foam core material. The disadvantage of the current stringer systems used is that the stringer may separate from the foam core after frequent use. It would be desirable to provide a method of inserting a stiffening element by heat laminating it to the foam core so that a strong bond forms between stiffening element and the foam core.  
         [0009]     Typically, in use, the rider of a bodyboard grips the front edge close to one corner of the lead nose and front portion of the side edge of the bodyboard. The hand in the front edge plays a significant role in steering control and maneuvering the bodyboard. Successful completion of maneuvers requires the bodyboard to respond adequately to the rider&#39;s steering. Force applied to the bodyboard that only distorts the board does not help the rider in redirecting the board. Thus, a high degree of stiffness of the bodyboard is desirable. However, it may not be desirable to make the bodyboard very rigid entirely from the nose to the tail. For example, it may be desirable for the board to be more flexible at the portion between a transverse line about a quarter of the way from the nose and the lead nose. Such flexibility allows the rider to pull up the nose of board and keep the nose and lead corners from dropping under the water&#39;s surface in a dynamic situation where the nose is being forced downwardly. However, in the forward quarter of the board, it is generally considered desirable for the board to be very stiff along a transverse line so that the rider&#39;s steering inputs on one side of the board will effectively be transmitted to the opposite side of the board and redirect the opposite side. It is therefore more desirable to provide an improved foam core with stiffening element adapted to increase the stiffness of a selected portion of the board. It is also desirable to provide an improved foam core with stiffening element adapted to provide the resistance to flex along a transverse axis and yet allow adequate flexibility along a longitudinal axis of the foam core in the forward quarter of the board.  
         [0010]     The necessary condition to provide stiffening to a composite foam core is that the flexural strength of the coupled stiffening element has to be substantially higher than that of the low density base foam core. It is apparent that when applying polystyrene foam plate as the stiffening element to a polyolefin foam base core, the polystyrene foam plate contributes higher flexural strength and a stiffening effect.  
         [0011]     It is yet another object of the invention to provide an improved foam board having a polyethylene foam core coupled with stiffening element adapted to increase the stiffness of a selected portion of the board.  
         [0012]     It is yet another object of the invention to provide an improved foam core that has the structure stiffness advantages of a polystyrene foam core in the main body and the desirable resilient and shock absorption properties of polyethylene foam in the top and front portion of the board.  
         [0013]     It is yet another object of the invention to provide an improved bodyboard with stiffening element adapted to provide the resistance to flex along a transverse axis and yet allow adequate flexibility along a longitudinal axis of the foam core in the forward quarter of the board.  
       SUMMARY OF THE INVENTION  
       [0014]     The present invention provides the solution to the above-mentioned problem by introducing generally planar stiffening element composed of substantially polymer foam into a low density polyolefin foam base, forming a composite foam core. The stiffening element has substantial higher compressive strength and flexural strength than the foam core. The sport board according to the present invention may be constructed as a foam sled to ride on at snow-covered slopes or a bodyboard for body surfing on waves.  
         [0015]     The composite polyolefin foam core in accordance with the invention comprises a polystyrene foam plate laminated to a polyethylene foam plate. Polyolefin foam may comprise a polyolefin polymer, such as homopolymer or copolymer of polyethylene and homopolymer or copolymer of polypropylene, more preferable a low density polyethylene foam.  
         [0016]     The polystyrene foam plate is laminated to the low density polyolefin foam plate with substantially planar bonding surface through the use of a heat activated adhesive resin layer. The polystyrene foam plate may be a pure styrene foam or it may be a hybrid foam of styrene and ethylene or other compatible polymer such as ethylene vinyl acetate. In one aspect of the invention, the bonding surfaces are oriented in a direction generally parallel to the X-Y plane of the core. In another aspect, the bonding surfaces are oriented in a direction generally parallel to the X-Z plane of the core. In one embodiment the sports board includes a composite foam core consisting of a first core section of polyolefin foam, and a second core section of polystyrene foam, a bottom plastic layer, and a top plastic layer.  
         [0017]     The stiffening element may extend throughout the length of the sports board to provide an even stiffness to the board. Alternative, the stiffening element may selectively be applied to the rider supporting section of the board to provide a high compression resistance and flexural strength against the rider&#39;s weight. A front section of low density polyolefin foam may be bonded to the front end of the foam core complex to give a full frontal flexibility. A rear section of low density polyolefin foam may also be bonded to the rear end of the foam core complex if desirable. The resulting sports board with a flexible front section and a rigid supporting main body is particularly useful in the application of both snow sled and bodyboard. The stiffening elements provide the board with improved rigidity, allowing improved maneuvering of a bodyboard and higher sliding speed for a snow sled. It is particularly useful that the flexibility near the front quarter length of a bodyboard provides desirable flex to a rider to manipulate directional steering during wave surfing. In the snow sled application, the flexible front section provides desirable resilient and shock absorbing properties to the board, in particular for front impact. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0018]      FIG. 1  is a perspective section view of the first embodiment sports board.  
         [0019]      FIG. 2   a  is a diagram showing assembly of the flexible nose for the first embodiment.  
         [0020]      FIG. 2   b  is a cross-section view of the first embodiment sports board.  
         [0021]      FIG. 3  is a top view of the sports board.  
         [0022]      FIG. 4  is a cross-section view of the second embodiment.  
         [0023]      FIG. 5  is a close up view of the cross-section view of the second embodiment  
         [0024]      FIG. 6  is a diagram of the nose assembly of a soft nose sports board.  
         [0025]      FIG. 7  is a diagram of the nose assembly of a rigid nose sports board.  
         [0026]      FIG. 8  is a perspective section view of the third embodiment.  
         [0027]      FIG. 9  is a cross sectional view of the third embodiment.  
         [0028]      FIG. 10  is a cross-section exploded view assembly diagram of the third embodiment.  
         [0029]      FIG. 11  is a cross-section exploded view assembly diagram of an alternate version of the third embodiment.  
         [0030]      FIG. 12  shows the cross-section profile of embossment pattern.  
         [0031]      FIG. 13  is a cross-section exploded view assembly diagram of the fourth embodiment.  
         [0032]      FIG. 14  is a cross-section exploded view assembly diagram of the fifth embodiment.  
         [0033]      FIG. 15  is a cross-section exploded view assembly diagram of the sixth embodiment.  
         [0034]      FIG. 16  is a cross-section exploded view assembly diagram of the seventh embodiment.  
         [0035]      FIG. 17  is a cross-section exploded view assembly diagram of the eighth embodiment.  
         [0036]      FIG. 18  is a cross-section exploded view assembly diagram of the ninth embodiment.  
     
    
       [0037]     Each of the different embodiments shows a board having different construction and different handling characteristics. Similar elements are referred to by common call out numbers.  
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0038]     Construction  
         [0039]     Referring to  FIGS. 1, 2   a , and  2   b , the sport board  100  according to the present invention is constructed as a foam sled to ride on a variety of surfaces such as on water waves or snow-covered slopes. The foam sled  100  is an elongated board having a substantially planar main body with round edges and front tip deflected upward. The foam sled includes a polyethylene composite foam core assembly composed of a polyethylene composite foam core  105  which acts as the supporting main body of the board, a front section of low density polyethylene foam  123 .  
         [0040]     The composite foam core  105  has a top section of low density polyethylene foam  103  and a bottom section of low density polystyrene foam  102 . Alternatively, the low density polyethylene foam  103  and a bottom section of low density polystyrene foam  102  can be reversed so that the low density polyethylene foam  103  is below the low density polystyrene foam  102 . Preferably, the low density polyethylene foam  103  is above the low density polystyrene foam  102 .  
         [0041]     A central binding layer  106  is applied to bond the polyethylene foam and polystyrene foam, in which bonding surfaces are oriented in a direction generally parallel to the top surface of the board. The binding layers may be adhesive resin or copolymer foam of polystyrene and polyethylene. The adhesive resin layer may be selected from a group consisting of anhydride-modified ethylene/vinyl acetate, anhydride modified ethylene acrylate, ethylene/propylene copolymer, homogeneous ethylene/alpha-olefin copolymer, anhydride-modified polyolefin, ethylene/acrylic acid copolymer, vinyl acetate/acrylic copolymer, ethylene/methylacrylate copolymer, ethylene/vinyl acetate copolymer, and blends of the foregoing, may be employed. In addition to the central binding layer  106 , the polyethylene foam portion  103  and the polystyrene foam portion  102  may be heat bonded together.  
         [0042]     The polyethylene foam portion of the core  103  in conjunction with the polystyrene foam portion of the core  102  preferably substantially changes the rigidity of the composite core. The polystyrene foam section  102  of the core preferably has a density of between 1-5.4 pounds per cubic foot (lb/ft 3 ), and with a best mode of 1.5 lb/ft 3 . The thickness of the polystyrene foam section is preferably between 4 and 50 millimeters (mm), with a best mode of 8 mm. The density of the polyethylene foam section  103  preferably has a density of 1.6 to 6 lb/ft 3 , with a best mode of 2.2 lb/ft 3 . The thickness of the polyethylene foam section  103  is preferably 5-72 mm, with a best mode of 18 mm. The adhesive resin central binding layer  106  binds the polyethylene foam section  103  to the polystyrene foam section  102 . The adhesive resin central binding layer  106  and lower adhesive resin layer  107  preferably has a density of between 0.88 to 0.99 grams per cubic centimeter (g/cm 3 ) and has a thickness of between 0.02-0.15 mm. The best mode for the thickness of adhesive resin binding layer is 0.07 mm. If the binding layer is copolymer foam of polystyrene and polyethylene, it preferably has a thickness of between 1-6 mm and most preferably 2 mm.  
         [0043]     The top skin laminate  110  of sports board  100  comprises a top skin laminate of two layers including a polyethylene foam sheet  114  and a plastic film  116 . The bottom skin laminate  109  comprises layer successive laminated plastic layers beginning with adhesive resin layer  107 , then a polyethylene foam sheet  115  and a plastic plate on the very bottom  117 . The adhesive resin layer  107  retains the polyethylene foam sheet  115  to the foam core. The core is wrapped between polyethylene foam sheet layers including the upper polyethylene foam sheet  114  and the lower polyethylene foam sheet  115 . The upper polyethylene foam sheet  114  and the lower polyethylene foam sheet  115  both have a higher density than the composite foam core. Both have a density in the range of 2 to 10 lb/ft 3 , and preferably a density of about 6 lb/ft 3 , with a thickness in the range of 2-8 mm, preferably about 3 mm.  
         [0044]     Plastic film  116  is a graphically-imprinted polyethylene film. The film may be a single layer or double-layer film. The graphics on layer  116  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. Plastic film  116  has a thickness of between 0.03 to 0.3 mm, and preferably a thickness of about 0.14 mm. Layer  116  has a density in the range of 0.91 to 0.98 g/cm 3 , and preferably a density of about 0.95 g/cm 3 . The graphic may be printed on the bottom side of the graphically imprinted polyethylene film  116 . The graphic may be reversed patterned so that it shows through a clear, transparent or translucent graphically imprinted polyethylene film  116 . The graphically imprinted polyethylene film  116  is bonded to the layer below it which is the polyethylene foam sheet  114 . The bonding between the graphically imprinted polyethylene film  116  and the polyethylene foam sheet  114  can be by heat bonding, adhesive or the like. Heat bonding using heated rollers is preferable.  
         [0045]     A front section  123 ,  FIG. 2   a  may be made out of the same blank material as the low-density polyethylene foam plates  103  and is heat bonded to the front end of the composite foam core  105  to allow greater nose flexibility for improved impact shock absorption. Thus, in the present embodiment of the invention, the sled  100  provides the dual advantages of high flexural strength against the user&#39;s riding load as well as maintaining the desirable shock absorbing property of polyethylene foam in the nose region.  
         [0046]     The bottom plastic plate  117  is 0.3-2 mm in thickness with a best mode of 0.5 mm. The bottom plastic plate  117  further has a preferred range of density in the range of 0.91-0.98 g/cm 3 , with a best mode of 0.95 g/cm 3 .  
         [0047]      FIGS. 3, 4  and  5  show a second embodiment of the present invention in a bodyboard  200  for surfing or body boarding. The bodyboard  200  is generally a planar board having a bottom surface, a top surface, front surface, tail surface and two side rail surfaces, the board is characterized by having two angularly outwardly extending side rails  218  and  219  also having plastic composition. The composite foam core  205  has the same composition and construction as the composite foam core  105  of the first embodiment. The foam complex  205  also consists of a top section of low density polyethylene foam  203  laminated to a bottom section of low density polystyrene foam  202  through a central binding layer  206 . The bottom of the composite foam core further receives an adhesive resin layer  207  adhering an additional polyethylene foam sheet  215  to the bottom of the foam core. The plastic plate  217  similarly adheres to the polyethylene foam sheet  215 .  
         [0048]     Similar to the first embodiment, a front section  223  also called a nose  223  may be made out of the same blank material as the low density polyethylene foam plate  203  and bonded to the front end of the laminate foam complex  205  to allow greater nose flexibility for improved maneuvering and greater directional control by the rider. The front of nose section  223  is shown as a polyethylene core in  FIG. 6 . The front nose section may be bonded by adhesive or thermal lamination to the body of the board which is the laminate foam complex  205 .  
         [0049]     Alternatively, the stiffening elements  202  may extend throughout the length of the foam core assembly  201  to provide a higher and even stiffness to the entire length of the bodyboard  200 . The stiffening element such as the polystyrene foam layer  202  provides greater stiffness as shown in  FIG. 7 .  
         [0050]     The deck layer  210  and lower rail layer  212  are both polyethylene foam. They have a thickness in the range of 2 to 8 mm and preferably of about 4.5 mm and a density in the range of 4 to 10 lb/ft 3  and preferably of about 7 lb/ft 3 . The slick layer  217  is a polyethylene film. Layer  217  has a thickness in the range of 0.3 to 2 mm and preferably of about 0.50 mm and a density in the range of 0.91 to 0.98 g/cm 3  and preferably of about 0.95 g/cm 3 . Layer  215  is polyethylene foam. Layer  215  has a thickness in the range of 2 to 8 mm and preferably of about 3 mm and a density in the range of 2 to 10 lb/ft 3  and preferably of about 6 lb/ft 3 . The low density foam  203  is of polyethylene having a thickness in the range of 5 to 72 mm, preferably of 38 mm. The low density foam  203  has a density in the range of 1.6 to 6 lb/ft 3  and preferably of about 2.2 lb/ft 3 . The low density foam  202  is of polystyrene having a thickness in the range of 4 to 50 mm, preferably of 12 mm. The low density foam  202  has a density in the range of 1 to 5.4 lb/ft 3  and preferably of about 1.5 lb/ft 3 .  
         [0051]     The third embodiment  300  of the present invention comprises a foam carpet style stiffening element layer. As seen on  FIG. 8 , a top printed graphic  301  is printed on the underside of the outside film layer  318  which is backed by inner film  319  or printed on the outside layer of inner film  319 . The laminate of the outside film layer  318  and inner film layer  319  is bonded over polyethylene foam sheet  303 . The polyethylene foam sheet is adhered or heat bonded over the stiffening layer  302  providing stiffness to the polyethylene foam sheet. Preferably, the adhesive resin central binding layer  106  binds the polyethylene foam section  303  to the polystyrene foam section  302 . An adhesive resin layer  307  applied to the underside of the stiffening layer shown as an polystyrene foam sheet  302  provides adhesion between the bottom plastic plate  317  and the polystyrene foam layer  302 .  
         [0052]     A cross-section is shown in  FIG. 9  showing the different layers of the third embodiment. The outer film  318  preferably has a density of 0.91 to 0.98 grams per cubic centimeter with a best mode of 0.95 grams per cubic centimeter. The outer film thickness is preferably between 0.02 and 0.15 mm, with a best mode of 0.07 mm. The inner film  319  has a similar density as the outer film and has a thickness preferably between 0.01 and 0.15 mm, with a best mode of 0.07 mm. The polyethylene foam sheet  303  is preferably between 5 and 45 mm, with a best mode of 14 mm and the polystyrene foam sheet is preferably between 3 and 15 mm, with a best mode of 5 mm. Again, an adhesive resin central binding layer  106  preferably binds the polyethylene foam section  403  to the polystyrene foam section  402 .  
         [0053]     The third embodiment can be further modified by reversing the orientation of the sheets. The top plastic skin as shown in  FIG. 10  over lies the polyethylene foam sheet which overlies a stiffening element polystyrene foam sheet which overlies a bottom plastic skin. If we turn the board upside down as shown in  FIG. 1 , the top plastic skin becomes the bottom plastic skin and the bottom plastic skin becomes the top plastic skin. Also, the polystyrene foam layer and the polyethylene foam layer become reversed as shown in  FIG. 11 . When the expanded polystyrene foam layer  302  is above the polyethylene foam layer  303 , the expanded polystyrene foam layer is bonded to the top plastic skin with an adhesive resin layer applied between the expanded polystyrene foam layer  302  and the top plastic skin. Typically, the expanded polystyrene foam layer will have an encapsulating adhesive resin layer so that the expanded polystyrene foam layer can bond to the polyethylene foam core portion  303  and either the top plastic skin, or an overlying backing foam layer.  
         [0054]     Furthermore, an embossing pattern can be made on the top plastic layer as shown in  FIG. 12 . The embossing pattern is preferably a hexagonal oriented matrix of round depressions, which can be applied by a heated profile roller. As shown in  FIG. 13 , the fourth embodiment  400  of the present invention comprises a polyethylene foam sheet  410 , overlying a composite foam core assembly  405  composed of a top section of low density polyethylene foam  403 , a central binding layer  406  and a bottom section of low density polystyrene foam  402 , overlying an adhesive resin layer  407 , overlying a polyolefin foam layer  415 , overlying an inner film  429 , overlying an outer film  428 , overlying a plastic plate  427 . A graphic pattern is printed on the outer surface of the inner film or on the inner surface of the outer film and the graphic pattern is visible outside the plastic plate.  
         [0055]     As shown in  FIG. 14 , the fifth embodiment  500  of the present invention comprises a polyethylene foam sheet  510 , overlying an adhesive resin layer  504 , overlying a composite foam core assembly  505  composed of a top section of low density polyethylene foam  502 , a central binding layer  506  and a bottom section of low density polystyrene foam  503 , overlying a polyethylene foam sheet  515 , overlying a plastic plate  517 .  
         [0056]     As shown in  FIG. 15 , the sixth embodiment  600  of the present invention comprises a top plastic film  618  overlying a polyethylene foam sheet  619 , overlying a composite foam core assembly  605  composed of a top section of low density polyethylene foam  603 , a central binding layer  606  and a bottom section of low density polystyrene foam  602 , overlying a bottom plastic skin  609 .  
         [0057]     As shown in  FIG. 16 , the seventh embodiment  700  of the present invention comprises the same construction of layers as embodiment  600 . An additional layer of adhesive resin layer  721  is interposed between the polyethylene foam sheet  719  and the composite foam core assembly  705 .  
         [0058]     As shown in  FIG. 17 , the eighth embodiment  800  of the present invention comprises an outer film  818  overlying an inner film  819 . The inner film is bonded to the polyethylene foam sheet  814 . The polyethylene foam sheet is bonded to a composite foam core assembly  805  composed of a top section of low density polyethylene foam  802 , a central binding layer  806  and a bottom section of low density polystyrene foam  803 . The polystyrene foam core bottom portion is overlying an adhesive resin layer  807  which bonds the polystyrene foam core bottom portion  802  to a polyethylene foam sheet  815 . The bottom polyethylene foam sheet  815  overlies a plastic plate  817 .  
         [0059]     As shown in  FIG. 18 , the ninth embodiment  900  of the present invention comprises an outer film  918  bonded to an inner film  919 . The inner film  919  overlies a polyethylene foam sheet  914 , which overlies a composite foam core assembly  905  composed of a top section of low density polyethylene foam  902 , a central binding layer  906  and a bottom section of low density polystyrene foam  903 , which overlies a bottom adhesive resin layer  907 , which overlies a polyethylene foam sheet  915 . The bottom polyethylene foam sheet  915  overlies an inner film  929 , which overlies an outer film  928 , which overlies a plastic plate  927 . A graphic pattern is printed on the outer surface of the inner film or on the inner surface of the outer film and the graphic pattern is visible outside the plastic plate.  
         [0060]     Fabrication  
         [0061]     Sportsboard  100  is formed in a series of steps. The first step is to make the foam core complex laminate portion  105 . A thin coating of adhesive resin is applied to one surface of the polyethylene foam plate by extruding a thin film layer of adhesive resin onto the surface to be bonded with polystyrene foam plate. The resulting laminate is then bonded to the polystyrene foam plate using a conventional heat laminating process. Similarly, a thin coating of adhesive resin is applied to the polyethylene foam sheet side of the polyethylene foam sheet/bottom plastic plate laminate. The resulting laminate is then heat laminated to the polystyrene foam plate of the foam core complex. These laminates are then cut and configured to the desired shape and size. The top skin is then heat laminated to cover the top and edge surface of the composite foam core.  
         [0062]     The thickness of the layers can be changed in relation to the type of board that is desired. For example, in the situation of a foam sled a combination of top polyethylene foam section and a bottom polystyrene foam section core is an ideal composite foam core for a snow sled application. The soft and resilient top deck provides a comfortable riding surface with excellent shock absorbing property. The rigid polystyrene bottom core section provides the rigidity for higher sliding speed and directional stability.  
         [0063]     In the example of a bodyboard, a regular polystyrene foam core may be too stiff. Straight polyethylene foam core bodyboard has the drawback of insufficient rigidity and is heavier than a polystyrene foam core bodyboard. A hybrid foam core of polystyrene foam and polyethylene foam make the board more rigid and less weight than a polyethylene foam core board. At the same time the polyethylene foam section of the composite core responses better with the rider&#39;s bending force due to the better elasticity of the polyethylene foam section.  
         [0064]     Generally, fabrication by heat laminating or adhesive resin bonding of various layers of plastic film and film is well known in the art. A variety of references show construction techniques for assembling a sports board having a backing foam layer. Szabad U.S. Pat. No. 4,850,913 incorporated herein by reference teaches how to make a foam board with both the top and bottom surface completely covered by a laminate PE film and PE foam sheet. Also a variety of references shows use of graphic film on a sports board. A variety of references show use of dual layer graphic film on a foam core such as Schneider U.S. Pat. No. 5,211,593 incorporated herein by reference which teaches a polyethylene foam core.  
         [0065]     Therefore, while the presently preferred forms of the sports board and its derivative 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. For example, the sports board of the first embodiment may have its bottom plastic plate replaced by the multi-layer bottom plastic plate of the board.