Abstract:
A method for coating an article, including the steps of: (a) coating a surface of the article with an unsolidified resin composition that, upon solidification, forms a polymeric matrix on the surface of the article; (b) applying particles of rubber to the coated surface prior to solidification of the resin composition; and (c) causing or permitting the resin composition to solidify on the surface to form the polymer matrix with the rubber particles embedded therein. Also, an article coated by the method. In a preferred embodiment, the article is a hockey stick.

Description:
FIELD OF THE INVENTION  
         [0001]    The invention relates to a method for coating articles, such as hockey sticks, baseball bats and tennis rackets, with a composition comprising particulate rubber. The invention also relates to articles so coated.  
         BACKGROUND OF THE INVENTION  
         [0002]    Until relatively recently, most hockey sticks were made of wood. The manufacturing process of these most common and conventional hockey sticks provides laminations of wood with the bend, curve and shape of a blade surface followed by a wrap of fiberglass cloth or mesh. The blade surface is then dipped or coated with resin.  
           [0003]    In use, the stick rides an ice surface ahead of a skater, which results in a grinding off of the resin on the heel of the blade surface. Moisture can then attack the laminations of wood with resultant de-lamination and structural failure of the blade. To prevent this, over the years hockey players have covered their sticks with covering materials, including tapes, adhesive or friction adhesive strips and rubber sleeves, to protect the blade surface and to provide a desired “feel” for a hockey puck. Tape has been the most common covering material. Nevertheless, tape has a number of drawbacks, including (a) a less than satisfactory “feel” due to insufficient resiliency of the tape material; (b) hockey tapes absorb a significant amount of water which increases the weight of the hockey stick and reduces the adhesion of the tape to the blade; (c) a less than desirable protection of the blade surface; and (d) the tape becomes undone and needs frequent reapplication or repair.  
           [0004]    Recently, hockey sticks have been manufactured comprising composite and/or synthetic materials, such as KEVLAR, in part to address the durability problems associated with wood sticks and in part because they are lighter in weight and offer more predictable performance. Nevertheless, the blades of such sticks are extremely hard and stiff and do not provide the “feel” of wood. Accordingly, hockey players have resorted to taping the new composite and synthetic blades in the hope of regaining the familiar feeling of wood. However, tape applied as a covering to a synthetic or composite hockey stick blade has the same drawbacks as tape applied to a wood blade (see above).  
           [0005]    A number of attempts have been made to address the aforementioned and other problems attendant to the use of wood or synthetic hockey stick blades. For example, U.S. Pat. No. 5,332,212 to Susi et al describes a hockey stick blade coated with an elastomeric polymer, such as polychloroprene, to provide a coating having characteristics that are designed to improve the “feel” of the blade. U.S. Pat.No. 6,364,793 to Valarik describes an adhesive layer comprising grains of corundum, ceramics, limestone, glass, rubber, textiles or plastics, that is applied to a hockey blade surface to reduce the slipperiness of the blade surface.  
           [0006]    The prior art solutions have been less than satisfactory in that they do not provide a hockey stick blade with an optimal or desired “feel” for a hockey puck. Moreover, in the case of U.S. Pat. No. 6,364,793, the use of a pressure sensitive adhesive to adhere a composition comprising granular material to the blade of a hockey stick presents difficulties in bonding of the pressure sensitive adhesive to the blade surface. In addition, the need to formulate the composition comprising the granular material prior to adhering the composition to the blade surface limits the amount of granular material that can be incorporated into the composition. What has been needed is a covering for a hockey stick blade that is free of the drawbacks discussed above and that provides a desired “feel” for a hockey puck.  
           [0007]    The inventor has now found that a hockey stick with a desirable “feel” for a hockey puck can be made by incorporating particulate rubber into a polymer matrix in situ on the surface of a hockey stick blade.  
         SUMMARY OF THE INVENTION  
         [0008]    In accordance with the invention, there is provided a method for coating an article comprising:  
           [0009]    (a) coating a surface of the article with an unsolidified resin composition that, upon solidification, forms a polymeric matrix on the surface of the article;  
           [0010]    (b) applying particles of rubber to the coated surface prior to solidification of the resin composition; and  
           [0011]    (c) causing or permitting the resin composition to solidify on the surface to form the polymer matrix with the rubber particles embedded therein.  
           [0012]    In a preferred embodiment of the invention, the article is a hockey stick comprising a handle portion and a blade portion, with the coating being applied to the blade portion of the hockey stick.  
           [0013]    In another preferred embodiment, the resin composition comprises a curable resin and a curing agent, wherein the curable resin comprises at least one resin selected from the group consisting of a urea resin, a phenol resin, an imide resin, an epoxy resin and a vinyl ester resin. The method comprises a step of mixing said curable resin and said curing agent together prior to said coating step (a).  
           [0014]    In a further preferred embodiment, the method comprises pressing the rubber particles onto said surface after said step (b) and prior to said step (c). The method also can include a step of forming a design or alphanumeric characters in the rubber particles applied to the surface in step (b) prior to said pressing, and/or forming ridges on the surface prior to said pressing.  
           [0015]    There is also provided in accordance with the invention a hockey stick comprising a handle portion and a blade portion, the blade portion having a surface comprising a particulate rubber coating embedded in a cured polymer matrix, the particulate rubber comprising rubber that can pass through a 20 mesh minus screen. In a preferred embodiment, the particulate rubber particles cover an area of the surface of between 15-35 square inches. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]    A fuller understanding of the present invention will become apparent from the following detailed description when read in conjunction with the accompanying drawings in which:  
         [0017]    [0017]FIGS. 1 a - c  diagrammatically depict steps of a method used for coating an article according to the present invention;  
         [0018]    [0018]FIG. 2 is a diagrammatic view showing a pressing tool used to press rubber particles onto the surface of a hockey stick blade according to one aspect of the present invention; and  
         [0019]    [0019]FIG. 3 is a sectional view of a blade surface coated with a particulate rubber composition according to the present invention.  
     
    
     DETAILED DESCRIPTION  
       [0020]    In a preferred embodiment of the invention, a curable resin composition is prepared comprising a curable resin and a curing agent that reacts with the curable resin to promote curing thereof. A curing catalyst may optionally be added to accelerate the reaction between the curable resin and the curing agent. Rubber in the form of granules or particles is added to the curable resin composition after the curable resin and curing agent have been mixed together and the mixture has been applied to the blade of a hockey stick, but before curing of the resin has been effected. It is important that the rubber particles or granules be added to the mixture before the curing of the resin has been completed so that the rubber particles or granules can become embedded in a cured polymer matrix once the curable resin has been cured.  
         [0021]    This sequence of steps is shown in FIGS. 1 a - c , wherein FIG. 1 a  shows the mechanical mixing with a stirring tool  4  of the components of a curable resin composition  2  comprising a curable resin and a curing agent. FIG. 1 b  shows the application of the mixture to the blade surface  6  of hockey stick  8  by means of a spread tool  10 . Alternatively, the blade surface  6  may be dipped into the resin composition, with prior masking of those portions of the blade surface, if any, for which the application of resin composition is not desired. FIG. 1 c  shows the pressing of the blade surface  6  into granular rubber  12  so that the granular rubber may become incorporated into the resin composition on the blade surface.  
         [0022]    In a preferred embodiment of the invention, the stirring tool  4  can comprise means for creating a texture or pattern on the blade surface. For example, the resin composition can be applied to the blade surface with a putty knife with jagged edges that produce evenly spaced ridges in the resin mix. Texturing tools can range from corrugated surfaces to cross-hatched or ridged surfaces accomplished through the use of suitable utensils, such as kitchen cooking utensils. The formation of ridges or crosshatching in the blade surface is also possible and may be used to aid in incorporation of the granular rubber into the resin mix.  
         [0023]    [0023]FIG. 2 shows a further preferred embodiment of the invention wherein a stamp or press tool  14  is used to press the granular rubber  12  into the resin composition on the blade surface  6  in the direction shown by arrows  20 . In this step, the tool  14  can be used to press or stamp any of a variety of patterns into the granular rubber while the rubber is being pressed into the resin composition on the blade surface. For example, the tool  14  may be used to create a desired design or logo on the blade surface. Alternatively, a design or logo can be applied to the granular rubber with spray paint using a stencil or any other suitable technique. FIG. 3 shows a logo  16  that may be cut in or painted on granular rubber  12  on blade surface  6 .  
         [0024]    The resin composition of the invention is preferably one comprising a curable or reactive resin wherein the granular rubber can adhere to the curable resin composition prior to the resin being cured, and wherein the granular rubber becomes embedded in a polymer matrix formed upon curing of the curable resin. The curable or reactive resin of the invention can, for example, comprise one or more resins selected from the group consisting of urea resins, phenol resins, imide resins and vinyl ester resins, with epoxy resins and polyol resins presently being preferred and epoxy resins being the most preferred.  
         [0025]    Epoxy resins constitute a broad class of polymeric materials characterized by epoxide groups which are cured by reaction with certain catalysts or curing agents to provide cured epoxy resin compositions with desirable properties. One class of curing agent is the amines. The most commonly used amine curing agents are aliphatic amines such as diethylenetriamene, trietheylenetetramine and the like, and/or polyoxyalkylene polyamines, such as polyoxypropylenediamines and triamines. Epoxy resin compositions comprising a curable epoxy resin and a curing agent that are usable in the present invention are described, for example, in U.S. Pat. No. 6,417,316 to Wiesendanger et al and U.S. Pat No. 4,178,426 to Waddill. These patents are incorporated herein by reference.  
         [0026]    Curing agents for polyol resins include isocyanates, and a preferred polyol/isocyanate curable resin system for use in the invention is a product marketed under the trademark AMERAGUARD AG 2000 manufactured by Armaguard Coatings Inc. of Alberta, Canada. This product is a two-component elastomer spray system comprising a polymeric isocyanate (polymeric diphenylmethane 4, 4 diisocyanate) as a first component and a polyether polyol as a second component. The product may be applied to the surface of a hockey stick blade (either wood or synthetic) as a heated spray composition. Resins within the heated spray composition will cure upon cooling. Accordingly, the blade surface treated with the heated spray should be immediately immersed in pulverized rubber such that, upon cooling of the resin composition, the rubber binds to and becomes embedded in the cured resin.  
         [0027]    The rubber particles for use in the invention may be natural or synthetic rubber particles. The particles are preferably finely ground rubber known as “rubber dust” that has been, for example, reclaimed from used rubber products and, in particular, from vehicle tires by processes that are well known in the art. For example, U.S. Pat. No. 5,299,744 to Garmater and U.S. Pat. No. 6,425,540 to Morris et al (the contents of which are incorporated by reference) describe apparatus and methods for grinding of rubber material to form finely ground rubber particles. The inventor has achieved superior results using rubber dust reclaimed from recycled tire shavings that have been granulated and passed through a twenty (20) mesh minus screen. Twenty mesh minus is a term of art indicating that the dust will pass through a one-square-inch mesh of 20 holes horizontally by 20 holes vertically. For use in the invention, it is preferred that the rubber dust particles be able to pass through at least a five (5) mesh minus screen. The rubber dust particles would preferably not be so small as to pass through an eighty (80) mesh minus screen. Most preferred dust particles for use with the present invention would be able to pass through a ten (10) mesh minus screen but would not be able to pass through a thirty (30) mesh minus screen.  
         [0028]    Larger particles than the preferred particles described above can and have been successfully applied to a hockey stick blade by the inventor. It may be appreciated in this regard that the grain, size and type of the rubber particles will depend on the surface to which they are applied and the desired “feel” to be imparted to the article coated with the rubber particles. The surface to be coated is not limited and requires only that the resin composition applied to the surface be one that, upon solidification or curing, will (a) adhere to the surface, and (b) bind the rubber particles. For example, the invention may be used with any of the materials that are presently used in hockey sticks, including wood, aluminum and composite materials such as fiber/resin composites. Such fiber/resin composites may include epoxy resins and graphite or aramid fibers, such as KEVLAR brand aramid fibers sold by E.I. DuPont de Nemours and Company of Wilmington, Del.  
         [0029]    The coated hockey stick blade produced by the methods described above will comprise a blade surface having a coating of particulate rubber incorporated into a cured polymer matrix. The particulate rubber will preferably cover substantially the entirety of the striking surface of the blade without gaps between the rubber particles. Preferably this will comprise an area of between about 15-35 square inches on one or both sides of a hockey stick blade. This will insure that, when the coated hockey stick blade is used to strike a hockey puck, a particulate rubber-containing surface of the blade will be available to make contact with the puck. This will provide the user of the hockey stick blade with a desirable “feel” for the hockey puck. It will also serve to provide for a durable protection of the blade surface.  
       EXAMPLES  
     Example 1  
       [0030]    20 mesh minus rubber dust particles refined from recycled tire shavings were obtained from Community Tire Company in St. Louis, Mo. A five (5) gallon pail was filled with this rubber dust. A hockey stick blade was coated with a heated spray of AMERAGUARD AG 2000 and the stick blade was immersed in the pail. The spray was allowed to cool and cured in about 30-45 seconds. The stick with a coating of the rubber dust particles was ready to use in a matter of minutes after the spray treatment.  
       Example 2  
       [0031]    A common household two-component epoxy paste of the brand name PC-7 made by Protective Coating Company Corporation of Allentown Pa. was purchased. The two-components were mixed together and applied with a spreading tool to a hockey stick blade. The rubber dust particles described in Example 1 were immediately pressed into the epoxy coating on the surface of the blade and the epoxy resin was allowed to cure for 8-10 hours. The treated hockey stick was then tested in play and was found to have superior “feel” for a hockey puck.  
         [0032]    Although the invention has been described above with particular reference to a hockey stick blade, it may readily be appreciated that the methods and coatings of the invention are not so limited and may be applied to articles used in other sports and in other endeavors. These and other modifications and changes can be made without departing from the scope of the invention as defined by the following claims.