Abstract:
A texture coating for golf club heads provides a durable and aesthetically pleasing exterior for wood, iron or putter golf club heads. The texture coating is a combination of a medium material, resin particles and a coupling agent. In a preferred embodiment the medium is a paint, the resin particles are olefins, most preferably polyethylene or polypropylene, and the coupling agent is a silane compound.

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
     Not Applicable 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a coating material for a golf club head. More specifically, the present invention relates to a texture coating exhibiting improved durability and aesthetic appearance on golf club head surfaces. 
     2. Description of the Related Art 
     A coating applied to a golf club head can provide various functional and aesthetic properties not available from structural material of the golf club head. Included among these functional characteristics are environmental protection from sun, moisture and oxidation, in addition to performance enhancements including high and low friction surfaces to promote desired spin rate of a golf ball, improved aerodynamics and wear resistance. Aesthetic properties such as texture, color and surface finish play a significant role in overall appearance and consumer acceptance of a complete golf club. 
     A sole or bottom of the golf club head is exposed to ground contact during the striking of a golf ball, and high frictional forces encountered during ground contact require the bottom of the golf club be constructed of a highly durable material, such as stainless steel or titanium metal. While the metal surfaces have the requisite durability, functional and aesthetic properties are limited to those inherit properties of the metal material. Many inventors have incorporated coatings on golf clubs to enhance functional and aesthetic properties, as disclosed in the following examples. 
     One example is that of Winrow, et al., U.S. Pat. No. 5,851,158, discussing a high durability coating applied to a golf club head using a powder coating containing carbides, borides, nitrides or oxides. This powder coating process employs a supersonic gas velocity to apply the coating and vary one or more of: the club head weight location, loft of the striking face, hardness, surface texture, and deflection and spin rate of a golf ball upon impact with the striking face. 
     Another example is supplied by Card, U.S. Pat. No. 5,743,812, where a low friction polytetrafluoroethylene coating is applied to the striking face of the golf club head to reduce spin rate and increase distance of the golf ball upon impact with the striking face. 
     Yet another example is that of Yamawaki et al., U.S. Pat. No. 5,484,155, wherein a golf club head contains an aesthetic paint coating. However, the bottom of the golf club, which experiences the highest frictional forces, contains no paint in the highest wear portions. 
     Another purpose for coating is found in Cornish, U.S. Pat. No. 5,354,056, to minimize air resistance of the golf club head by utilizing a coating material to produce a rough surface finish. Sand may be mixed with glue to provide this rough surface finish providing resultant improvements in aerodynamics of the golf club. 
     A further example of reducing air resistance is provided by Nagai et al., U.S. Pat. No. 5,190,289 disclosing a coating around the periphery of a golf club head to produce a roughened surface. This coating reduces air resistance of the golf club during the golf swing and therefore provides higher club head velocity to impact the golf ball. 
     A further example of coating a golf club head is found in Kim, U.S. Pat. No. 4,951,953, where a diamond coating provides improved strength to the striking face of the golf club head, resulting in improved travel distance of the golf ball upon impact with the striking face. 
     Another example of coating a golf club head is provided by Temin, U.S. Pat. No. 4,241,115, where a wood golf club head is coated with a resin solution to render the wood impervious to moisture, resistant to damage from abrasives, shock and impact forces. 
     One more example of coating a golf club head is that of Rasmussen, U.S. Pat. No. 3,989,861, using abrasive particles in a soluble adhesive, applied to the striking face of the golf club head to increase the spin rate of a golf ball upon impact with the striking face. Suitable abrasives include sand, emory, powdered granite, pumice, boron carbide and aluminum oxide. 
     While the previously discussed coating examples exhibit various functional and aesthetic properties for golf clubs, a need still exists for a low cost coating to provide high durability in conjunction with improved aesthetics. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention comprises a texture coating with improved durability and aesthetic properties for golf clubs. In a preferred embodiment a mixture of a polymeric resin particles, a coupling agent and a medium are applied to a golf club head followed by a drying step to form the texture coating. Increased durability results from deformation of the resin particles when exposed to impact or shear forces. In other words, the resin particles absorb energy by deforming and thereby protecting the aesthetic properties of the medium. The polymeric resin is selected from thermoset or thermoplastic resins, with thermoplastics such as polyethylene or polypropylene being a preferred embodiment. Possible shapes for the polymeric resin particles are not limited, but a preferably smooth surface helps to distribute the particles uniformly throughout the medium with a most preferred embodiment having a spherical shape with a diameter of less than 50 microns, most preferably 18-50 microns. Pigments can be incorporated into the polymeric resin particles to augment or contrast the coloring of the medium. 
     The coupling agents of the present invention help bind the polymeric resin particles and the medium to a surface of the golf club head. Preferred embodiments of the coupling agent include silane and inorganic acids. 
     The medium can be selected from any number of formulations, with paints being a preferred embodiment. Preferred paint embodiments for the medium include thermosetting polyamides and urethanes. 
     Additional additives can be incorporated into the texture coating, examples include ultraviolet (UV) stabilizers, color enhancers, antioxidants, moisture inhibitors, fluorescent or luminescent compounds and the like. One method for authenticating the golf club head of the present invention is to imprint a distinctive mark on the texture coating using the fluorescent or luminescent additive. Under natural light the mark is invisible but appears when exposed to light of a specified range of wavelengths. This same effect can be obtained by mixing the fluorescent or luminescent into the texture coating before application to the golf club head. 
     One object of the present invention is to improve durability of coatings applied to a golf club head. 
     Another object is to protect a non-durable first coating with a durable second coating on a golf club head. 
     A further object of the invention is producing a semi-gloss finish to the surface of a golf club head which will resist marring during incidental impact with other objects. 
     Another object of the invention is to help identify authentic golf clubs by applying a coating containing a fluorescent or a luminescent additive. 
     Having briefly described the present invention, the above and further objects, features and advantages thereof will be recognized by those skilled in the pertinent art from the following detailed description of the invention when taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a bottom view of a wood golf club head showing an embodiment of a texture coating of the present invention. 
     FIG. 2 is a front perspective view of the wood golf club head showing an embodiment of the texture coating of the present invention. 
     FIG. 3A is a cross-sectional view of section III, as shown in FIG. 1, illustrating an embodiment of the texture coating of the present invention, comprising resin particles within a medium. 
     FIG. 3B is an alternative embodiment of FIG. 3A, showing agglomerated resin particles within the medium of the present invention. 
     FIG. 3C is another alternative embodiment of FIG. 3A, showing agglomerated dissimilar size resin particles within the medium of the present invention. 
     FIG. 4 is a bottom view of an iron golf club head showing an embodiment of the texture coating of the present invention. 
     FIG. 5 is a heel view of an iron golf club head showing the texture coating of the present invention. 
     FIG. 6 is a top view of a putter golf club head showing an embodiment of the texture coating of the present invention. 
     FIG. 7 is a rear view of the putter golf club head showing the texture coating of the present invention. 
     FIG. 8 is a bottom view of the putter golf club head showing the texture coating of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Like numbers are used throughout the detailed description to designate corresponding parts of a golf club head and a texture coating of the present invention. 
     As shown in FIGS. 1 and 2 a wood-type golf club head  10  comprises a texture coating  20  of the present invention. The wood-type golf club head  10  further comprises a face region  12  for striking a golf ball (not shown), a rear region  14 , a toe region  16 , a heel region  18 , a bottom is region  22 , a top region  24  and a hosel inlet  26  for accepting a golf shaft (not shown). Structural material for the wood-type golf club head can be selected from metals and non-metals, with metals such as stainless steel and titanium being preferred embodiments. The bottom region  22  is a convex surface defining a first level, in a preferred embodiment a second level  23  is located in the toe region  16 , and a third level  25  is located in the heel region  18 . In a most preferred embodiment the top region  24  is coated with paint and the second and third levels,  23  and  25  respectively, are covered with the texture coating  20 . The face, rear, toe, heel, top and bottom regions,  12 ,  14 ,  16 ,  18 ,  24  and  22  respectively, are meant to describe general sections of the golf club head  12  and may overlap one another. 
     FIGS. 3A-C represent various embodiments of the texture coating  20 , as shown in cross-section of an area III in FIG.  1 . The texture coating  20  comprises a number of resin particles  30 , a medium  32  and a coupling agent (not shown). The resin particles  30  can be thermoset or thermoplastic resins, and in a preferred embodiment selected from olefins, fluoropolymers, polyamides and polyamines, in a most preferred embodiment selected from polyethylene or polypropylene. Although pictorially represented as spherical, the resin particles  30  can be selected from several shapes with smooth surfaces preferred to assist in uniform distribution throughout the medium  32 . Any numbers of conventional methods can be used to apply the texture coating  20 ; such as brushing, spraying, electrostatic methods, powder coating and two component systems. 
     Characteristics of medium  32  include an ability to mix with the resin particles  30  and bond to structural material of the club head  10 , followed by drying to a solid coating. Suitable material choices for the medium  32  include aqueous or organic solutions or suspensions, liquid adhesives and paints. In a preferred embodiment the medium  32  comprises a paint capable of binding the resin particles  30  and adhering to the surface of the club head  10 , with the resin particles  30  forming up to 20% by volume of the coating  20 . In a most preferred embodiment the resin particles  30  form 5% to 10% by volume of the texture coating  20 . An alternative embodiment includes one or more coatings, with the medium  32  being transparent in the texture coating  20  forming a topmost coating. 
     The coupling agent serves to alter the surface chemistry of the resin particles  30  and the medium  32 , thus promoting improved bonding both within the texture coating  20 , and to the surface of the golf club head  10 . Preferred embodiments of the coupling agent include silanes and inorganic acids such as phosphoric acid, with a most preferred embodiment being Silane 187A from Shell Chemical Co. 
     FIGS. 4 and 5 illustrates an iron-type golf club head  10   a  of the present invention with element numbers corresponding to those of FIGS. 1 and 2. A texture coating  20   a  is depicted on a bottom region  22   a , but may occupy any number of surfaces on the iron-type golf club head  10   a.    
     FIGS. 6-8 represents a putter-type golf club head  10   b  of the present invention with element numbers corresponding to those of FIGS. 1 and 2. A texture coating  20   b  is depicted on a top, toe, heel and back regions,  26   b ,  16   b ,  18   b  and  14   b  respectively, but may applied on any number of surfaces of the putter-type golf club head  10   b.    
     From the foregoing it is believed that those skilled in the pertinent art will recognize the meritorious advancement of this invention and will readily understand that while the present invention has been described in association with a preferred embodiment thereof, and other embodiments illustrated in the accompanying drawings, numerous changes, modifications and substitutions of equivalents may be made therein without departing from the spirit and scope of this invention which is intended to be unlimited by the foregoing except as may appear in the following appended claims. Therefore, the embodiments of the invention in which an exclusive property or privilege is claimed are defined in the following appended claims.