Abstract:
Horse hoof protection is obtained by incorporating a synthetic organic resin such as a urethane resin in the volume defined by the horse hoof bottom wall, suitably covered with a web fixed to the hoof bottom wall that is adhered to the resin. The resin protection is suitably free flowing into place, conforms to the contours of the hoof bottom wall, and adheres to the wall when cured. The protection by the resin is resilient and softer than the hoof wall and acts to cushion the hoof against shock.

Description:
REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of United States Provisional Application Serial No. 60/083,464 filed Apr. 29, 1998, and is a continuation of U.S. patent application Ser. No. 09/143,596 filed Aug. 31, 1998, now U.S. Pat. No. 6,131,665, which is in turn a continuation-in-part of U.S. patent application Ser. No. 09/098,820 filed Jun. 17, 1998 now U.S. Pat. No. 6,009,952 issue Jan. 4, 2000, the disclosures of which are incorporated herein. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Technical Field 
     This invention relates to horse hoof protection, and more particularly to improved methods and products for the cushioning of the horse&#39;s hoof and the blocking of ingress of harmful debris into the sensitive frog portion of the hoof. 
     2. Related Art 
     Webs of leather, plastic or rubber, called pads, attached to the hoof wall, and sized to extend across the hoof sole and cover the frog portion of the hoof are sometimes inserted under the horseshoe to protect the sensitive areas of the hoof Moisture or debris sometimes work their way into the open volume defined broadly by the hoof bottom wall comprising the hoof sole and frog, causing discomfort or harm to the animal. Efforts to fill the volume have involved adding resins to the sole and covering with the web. These expedients have not proved successful because of difficulties in handling the resins, available resins having too high viscosity to permit readily filling into the horse hoof volume, persistent resin tackiness, lack of fill of all interstices or voids within the volume, and undue final hardness of the resin. Further, known resins do not adhere to the web used to cover the hook frog, leaving space between the resin mass and the web or pad for incursions of debris. 
     SUMMARY OF THE INVENTION 
     It is an object of the invention to provide protection for horses&#39; hoofs, and cushioning for horses&#39; steps. It is a further object to provide a hoof packing method and product that flows easily and readily into the hoof volume and the interstices thereof yet sets up nearly immediately to a firm, somewhat resilient mass that adheres to the hoof volume walls against loss of the mass or incursions of debris. The invention method and product avoid the difficulties of resin tackiness, incursions of debris from loose or incomplete fill, undue hardness in the resin, and handling problems arising from use of putty-like or heavier resins which must be packed in rather than flowed in. It is a further object of the invention to provide a method of injecting resin into the volume defined by the hoof bottom wall, e.g. under a protecting web on a horse hoof or without such web, in which the interstices and surface voids of the volume are completely filled so that there is no incursion of debris, no handling problems with pasty or tacky resin systems, and the final result is a softer and more resilient mass than the horse hoof wall, the mass even being transparent to permit viewing of the horse&#39;s sole. Further it is an object to adhere the web or pad to the resin mass, making the hoof protection unitary and completely blocked against debris intrusion. 
     These and other objects of the invention to become apparent hereinafter are realized in the method of protecting a horse&#39;s hoof, including cleaning the open volume formed by the hoof bottom wall of debris, incorporating a rapidly curing synthetic organic resin into the volume, the resin having a viscosity such that the resin freely conforms to the contours of the hoof bottom wall, and curing the resin to a void-free solid in situ in hoof bottom wall adhering relation. 
     In this and like embodiments, typically, the method further includes selecting a urethane resin as the synthetic organic resin, the resin adhering to the hoof bottom wall; selecting as the synthetic organic resin an injectable resin, and injecting the resin into the volume against the hoof bottom wall in conforming relation therewith; and, where the volume has an open mouth, including also fixing a web across the volume open mouth, and thereafter incorporating the synthetic resin into the volume under the web, and curing; and, selecting as the synthetic resin a urethane resin having a cure time of less than about 2 minutes, tile cured resin adhering to the hoof bottom wall and said web. 
     In a further embodiment, the invention provides the method of protecting a horse&#39;s hoof having a hoof bottom wall forming an open volume, including cleaning the open volume of debris, fixing a web across the open volume, and incorporating a free-flowing, rapidly curing synthetic organic resin adherent to the hoof wall under the web and into the volume in hoof bottom wall conforming relation, and curing the resin to a void-free solid in situ adherent to the hoof bottom wall. 
     In this and like embodiments, typically, the invention method can include fixing the web in place with nails, fasteners, adhesive, or otherwise into the hoof bottom wall; fixing the web to the hoof with a horseshoe secured to the hoof bottom wall; selecting as the resin a urethane resin, selecting as the urethane resin a urethane resin having a cure time of less than about 2 minutes; or, preferably, selecting as the urethane resin a urethane resin having a cure time of less than about 25 seconds; hydraulically filling the volume with the resin and adhering the resin to the web against debris incursions between said web and said resin. 
     In either or both of the foregoing embodiments, typically, the method includes selecting a resin which when finally cured is softer than the horny wall of the hoof and cushions the hoof against shock; and, selecting a resin which is transparent or at least translucent when cured, so that the hoof sole is visible through the resin. 
     In a further embodiment, the invention provides the method of protecting a horse&#39;s hoof having a hoof bottom wall defined by the hoof frog and sole and forming an open volume, including combining from a pair of cartridges into a static mixer separate reactive resin components forming a rapidly curing synthetic organic resin in an amount suitable for hydraulically filling the volume, conforming the resin to the contours of the hoof bottom wall, and curing the resin to a void-free solid in situ. 
     In this and like embodiments, typically, the method includes adhering the synthetic organic resin to the hoof bottom wall during resin cure; and, covering the open volume with a web comprising leather, rubber or a synthetic organic resin, the web being adhered to the resin. 
     In a further embodiment, the invention provides a protected horse hoof comprising a hoof and a hoof bottom wall forming an open volume and a void-free, solid synthetic organic resin conformed with and adhered to the hoof bottom wall in volume filling relation such that the hoof volume is free of unfilled voids and interstices. 
     In this and like embodiments, typically, the synthetic organic resin within the volume is covered by a web fixed to the hoof, the cured synthetic organic resin is softer than the horny wall of the hoof and cushions the hoof against shock; the synthetic organic resin is formed from reactive resin components injected into the volume at a viscosity adapted to substantially fill the smallest spaces in the volume and conform to the hoof bottom wall surfaces in adhering relation; the synthetic organic resin is a urethane resin; and the resin is sufficiently transparent that the horse hoof sole is visible therethrough. 
     In yet another embodiment, the invention provides the method of protecting a horse from injury during walking or running, including filling the open volume defined by the horse hoof wall with a synthetic organic resin, such as a urethane resin, which cures to be softer than and adherent to the horse hoof wall, and curing the resin to a void-free solid in situ. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be further described in conjunction with the attached drawings in which: 
     FIG. 1 is a view in elevation of an unshod horse hoof, 
     FIG. 2 is a view of the horse hoof after addition of a horseshoe, the web and the resin mass according to the invention; 
     FIG. 3 is a view like FIG. 2, exploded; 
     FIG. 4 is a view taken on line  4 — 4  in FIG.  2   
    
    
     DETAILED DESCRIPTION 
     Horse hoofs are conventionally shod by nailing a horseshoe to the horny wall forming the outer portion of the hoof. Within the horny wall are the sole of the hoof and the sensitive frog portion of the hoof, generally referred to herein jointly as the hoof bottom wall. These portions of the hoof are not protected from damage from contact with moisture or other forms of debris and harmful objects. It is a common practice to add a web across the hoof sole, usually supported by the horseshoe or horseshoe nails to protect the sole of the hoof Debris can enter the open volume defined by the hoof bottom wall, even under the web unless the volume is filled with a suitable material. Suitable materials will fill all spaces in the volume ands prevent voids and interstices from occurring. In the past, foam resins have been employed, but they do not hold up against the stresses imposed in use and allow incursions of debris, moisture and contamination. Other materials are stiff and difficult to work with and like the foam systems do not adhere to the hoof bottom wall and thus allow, especially after wearing for a time, the incursion of debris which is uncomfortable and even harmful to the horse. The present invention uses a solid, noncellular, void-free resin to fill the open volume, suitably adherent to the hoof bottom wall against incursive attacks from debris and moisture even after a time of use. Tile preferred resins herein are injectable using dual cartridge dispensers which direct reactive components of low viscosity through a static mixer into the hoof volume where their initially low viscosity enables flow throughout the volume and into the nooks, crannies, interstices and voids of the volume and occurring on the hoof walls. The resin then sets up and adheres to the walls, void-free and more resilient than the surrounding hoof to cushion the steps of the horse while protecting from debris incursions. 
     With reference to FIGS. 1-4, the hoof  10  is shod with a shoe  12  fixed to the hoof wall  14  by nails  16 . An optional leather, synthetic organic resin plastic, or rubber material web  20  is stretched across the hoof sole portion  18 , and anchored there by the nails  16  and horseshoe  12 . The web  20  can be also affixed by any other suitable means such as adhesive, clamps, and the like. The use of the web is not necessary with the present resin masses owing to their rapid increase in viscosity within the hoof volume  22  and their final adhesion to the hoof bottom wall  19  sole and frog portions,  18 ,  30 . 
     The hoof open volume  22  is defined by the hoof bottom wall  19 , comprising the hoof sole portion  18  and the hoof frog portion  30 , has a mouth  23  which is closed by the web  20  extending laterally between the left and right portions  24 ,  26  of the hoof horny wall  14 . As noted, the use of the web  20  is not necessary in this invention. The volume  22  is filled with an injectable, e.g. liquid resin, forming a mass  28 . Because of rapid cure of the resin, e.g. in from less than 25 seconds to less than about 2 minutes, there is no need to support the resin in place until cure as with a web  20 , particularly with the faster curing resins, The terms hydraulically filled and hydraulically full herein refer to the filling with the liquid resin mass  28  of substantially all the voids, crevices and interstices of the hoof sole portion  18  including areas surrounding and covering the frog portion  30  of the hoof, and to filling the volume  22  from the hoof sole  18  to the web  20  so that incursions of debris including moisture into the volume  22  are blocked. 
     The resin used to form the mass  28  is desirably a highly fluid liquid which can be and preferably is injected into the volume  22  to spread throughout the volume, to contact all surfaces therein, and to adhere to such surfaces in a void eliminating manner. The resin mass  28  being comprised of solid (void-free) resin reactants and free of foam-formers will be free of voids and pockets of air or gas when cured, unlike foam systems which deliberately create voids. The resin mass  28  cures in place, i.e. in situ. Viscosities of the fluid form of the mass  28  are selected such that the incorporation of the mass into the volume  22  is quickly accomplished, in a matter of 5 to 20 seconds typically and usually less than a few minutes. Incorporation by injection rather than by hand packing as has been common with nonfluid volume fillers enables rapid distribution of the resin mass  28  through the volume  22  and the infilling of voids and interstices of the hoof bottom wall surfaces. Viscosities of less than about 25,000 and preferably less than 2500 centipoises may be used, with viscosities as low as that of water being useful. The resin can be any of the various known thermoplastic resins or thermosetting resins meeting the invention criteria of low viscosity upon incorporation such as by injection under the web, and rapid gelling or cure to a substantially solid viscosity, e.g. 100,000 centipoises. A rapidly high viscosity gives the resin mass  28  the ability to not flow from the volume  22 . This increased viscosity preferably happens in 10 to 20 seconds or less than 25 seconds, but other times, up to 2 minutes or more where conditions permit, and where the foregoing handling criterion is met can be used. Resin compositions are usefully packaged in dual cartridge packages from which they may be discharged through a static mixer tip to combine into a reactive mixture which is injectable into the volume  22 . For rapid cure to a sufficiently gelled state, the amount of catalyst should be selected in concert with desired cure time, e.g. 5% by weight of a urethane reaction catalyst for a 20 second cure to the adequately gelled state, with final cure occurring over the next day or so. 
     While resins, such as the preferred urethane resins herein may be initially tacky, this tackiness is lost upon fully curing. The preferred application method of incorporation by injection mentioned above makes tackiness or not unimportant since the resins can be injected directly under the previously applied web, if used, and no hand or spatula contact is required, even where the web is not used. 
     A further feature of the invention is the cure of the resin to a relatively soft and resilient state, e.g. to a hardness less and a softness greater than that of the horny portion of the hoof. Resilience of the resin is its capacity to deform and return to its undeformed condition substantially immediately and to persist in this resilient quality over substantially the life of the resin in the hoof volume  22 . Typically, this resilience is achieved by selecting reactants and reaction conditions known in the art to limit the degree of final cure to such that the resin mass  28  has resiliency to a degree that under the compression of the horse&#39;s weight it will yield slightly under the web, cushioning the horse&#39;s step and promptly and persistently recovering its original dimensions. A hardness value of 40 to 80 Shore A for the fully gelled, void-free resin is preferred. 
     A useful filler resin mass system is a urethane resin prepared from one or more isocyanates, catalysts, and various polyols, such as disclosed in U.S. Pat. No. 4,869,400, the disclosure of which is hereby incorporated herein. Desirably the mass  28  adheres to the hoof frog portion  30  and hoof sole portion  18 , and is held in place thereby. In addition, it is desirable to have the resin mass transparent or at least sufficiently translucent so as to permit viewing the underlying hoof sole portion  18  and frog portion  30 . Epoxies, polyesters, vinyl resins and other resins meeting the invention criteria can also be used. The term curing herein refers to polymerization, whether of the thermosetting or thermoplastic type, between resin components, or other processes by which a resin or resins change from a liquid to a solid state, including by loss of a diluent or solvent. 
     EXAMPLE 
     A fast-gelling, low hardness gel was prepared from a reactive urethane resin mixture comprising two parts of equal volume for dispensing from a dual cartridge dispenser in which dual pistons on a common yoke extrude the separate reactive components through a manifold and into a mix tip comprising a series of baffles arranged to cut and recombine the mixing materials as they progress through the mix tip. 
     Part A of the mixture comprised (all parts and percentages are by weight): 
     
       
         
               
               
             
               
               
             
           
               
                   
                   
               
               
                   
                 Parts 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 Composition-Side A 
                   
               
               
                 Methylene-bis-dicyclohexane diisocyanate (Desmodur W) 
                 134 
               
               
                 Polyoxy propylene oxide ether polyol, triol (6000 MW) 
               
               
                 (Multranol 3900) 
                 192 
               
               
                 D.B. (Double Boiled) castor oil 
                 28 
               
               
                 And 
               
               
                 Methylene-bis-diphenyl diisocyanate (Isonate 2143L) 
                 72 
               
               
                 And 
               
               
                 3-(triethoxysilyl)propyl isocyanate (Silane Y9030) 
                 24 
               
               
                 Composition-Side B 
               
               
                 Multranol 3900 
                 196 
               
               
                 Polyoxy propylene oxide ether polyol, diol (2000 MW) 
               
               
                 (Multranol 3600) 
                 83 
               
               
                 Polyoxy propylene oxide ether polyol, triol (450 MW) 
               
               
                 (Multranol 4012) 
                 96 
               
               
                 Ethylene diamine tetra propoxylate (Quadrol) 
                 38 
               
               
                 Butanediol, 1, 4 
                 17 
               
               
                 And 
               
               
                 Bismuth naphthenate (Coscat 83) 
                 21 
               
               
                   
               
             
          
         
       
     
     The first three Side A components were mixed together in a suitable vessel, then the second and third isocyanate components were mixed in, and the mixture put up in a first chamber of a dual chamber dispenser. Viscosity of the Side A composition was in the range of about 1000-2000 centipoises at about 25° C. The Side B components were mixed together without the Coscat catalyst, then the catalyst was added at the indicated high amount (about 5% by weight) and the mixture was put up in the second chamber of the dual chamber dispenser. The Side B viscosity was in the range of about 800-2000 centipoises, also at about 25° C. Importantly, the above Side A and Side B compositions are reactive to a urethane polymer when mixed in a 1:1 ratio, making this composition ideal for dispensing from a conventional 1:1 dual chamber cartridge. Other ratios can be used but they are less convenient, and the cartridge dispensers required, e.g. 2:1 are more costly. 
     A hoof treatment was effected by simultaneously expelling the contents of both chambers of the dual chamber dispenser through a common mix tip where they were intimately mixed under severe shear conditions into the volume defined by the hoof below the hoof pad. Injection took about 5 seconds. The like viscosities and the 1:1 mix ratio of the example composition make their packaging and dispensing to be readily accomplished. The sides react in the mix tip and within the hoof volume. The low viscosity of the mixed components enables the ready and rapid filling of the small interstices in the hoof wall. The mixture, however, after a working time of about 8 to 12 seconds, gels very rapidly, within about 20 seconds, so that the mixture remains disposed within the hoof volume. The farrier can put the hoof down after this brief gelling time, as the composition is adhered to the hoof wall, the web across the void, if used, and will not drop or squeeze out. The composition is solid and free of voids, cellularity and foam structure, but provides the desired cushioning effect noted above. The gelled resin was translucent to clear. Typical hardness values for the fully gelled composition are in the range of Shore A 40 to 80 after 24 hours at room temperature; thus hoof cushioning is achieved without a foamed compositions. 
     The foregoing objects of providing a hoof packing method and product that avoid debris incursions, protect the horse hoof by completely filling the voids and interstices therein, and remain resilient and cushioning are thus met.