Patent Application
20070060426
The present disclosure relates, through various exemplary embodiments, to the use of a particular class of laminates in sports balls. The laminates are used as an outer layer in sports balls to provide enhanced gripping characteristics.
The ability to grip, or maintain contact with a sports ball is a significant factor. This is particularly so for sports balls that are used outdoors where external agents such as rain, snow, dirt, or mud can interfere with gripping the ball.
Efforts to improve grippability of sports balls have included the use of anti-slip coatings applied to the outer surface of the ball, the use of particular surface patterns such as pebbling, and the incorporation of cushioning or padding within the ball to facilitate gripping. Although satisfactory, a need remains for another strategy by which to improve grippability of a sports ball.
In a first aspect, the present disclosure is directed to an inflatable sports ball comprising an inflatable carcass and a cover layer disposed on the carcass. The cover layer includes a laminate material defining an outer surface of the sports ball. The laminate material has a fiber component and a rubber component. The laminate material has a thickness of from about 0.5 to about 3 mm. The rubber component constitutes the outer surface of the sports ball.
In another aspect, the present disclosure provides an inflatable sports ball comprising a cover layer including a laminate. The laminate has a fiber component and a rubber component. The rubber component constitutes the outer surface of the sports ball. The fiber component is selected from the group consisting of cotton, acrylic, polyester, nylon, polypropylene, rayon, aramid and combinations thereof.
In another aspect, the present disclosure provides an inflatable sports ball comprising a cover layer including a laminate having a fiber component and a rubber component. The rubber component serves as the outer surface of the sports ball. The rubber component is selected from the group consisting of natural rubber, styrene-butadiene rubber, isoprene rubber, butadiene rubber, ethylene-propylene rubber, butyl rubber, chloroprene rubber, nitrile rubber and combinations thereof.
These and other non-limiting embodiments will be more particularly described with regard to the drawings and the detailed description set forth below.
The following is a brief description of the drawings which is presented for the purposes of illustrating the disclosure set forth herein and not for the purposes of limiting the same.
In accordance with the present discovery, a laminate of (i) a fiber component and (ii) a rubber component is utilized as an outer cover layer in a sports ball. The coated cover material is formed from a plurality of fibers, i.e., the fiber component (i), compressed or otherwise layered together in an array to form a mat with rubber material, i.e., the rubber component (ii), disposed above, below, and/or throughout the spaces between the fibers. Preferably, the fiber component (i) is a collection of woven or non-woven fibers that are in a layer form or baft, which fibers are coated with the rubber component (ii), which generally includes one or more rubbers or rubber-agents. If the fibers are in a woven form, that layer is referred to herein as a “fabric”. The coating of the rubber can be of one side of the fibrous layer, or both sides. A wide array of rubber or types of rubber can be utilized, as more fully described herein.
The laminates described herein are used in sports balls, and specifically, as outer cover layers therein, such that the rubber component constitutes the outer layer of the sports ball. In certain embodiments, the relatively thin rubber coating and the fibrous layer underneath result in a ball outer surface that is somewhat textured, yet includes a tactile, resilient, and easily grippable surface. Surprisingly, the outer ball surface resulting from the laminates described herein exhibits enhanced gripping characteristics.
More specifically, the fibers used in the fibrous layer can be either natural fibers or fibers formed from synthetic materials. Alternately or in addition to the synthetic fiber, natural fibers can be used, at least in part, such as sisal fiber, jute fiber, kenaf fiber, coconut fiber, corn fiber, soybean fiber, wool fiber, cotton fiber or hemp fiber. Non-limiting examples of suitable synthetic fibers for forming the laminates described herein include acrylic, polyester, nylon, polypropylene, rayon, aramids such as Kevlar®, and the like. In addition, it is contemplated that carbon fibers could be used. Depending upon the application, synthetic fibers may be selected over natural fibers due to their often superior strength and durability. More than one type of fiber may be used. Monocomponent and/or bi-component fibers can be used.
Additional non-limiting examples of synthetic fibers suitable for the various laminates described herein may be produced from a wide variety of thermoplastic polymers. Suitable polymers for forming the fiber component include, but are not limited to, polyolefins, e.g., polyethylene, polypropylene, polybutylene and the like; polyamides, e.g., nylon 6, nylon 6/6, nylon 10, nylon 12 and the like; polyesters, e.g. polyethylene terephthalate, polybutylene terephthalate and the like; polycarbonates; polystyrenes; thermoplastic elastomers, e.g., ethylene-propylene rubbers, polyurethane, styrenic block copolymers, copolyester elastomers and polyamide elastomers and the like; fluoropolymers, e.g., pollytetrafluorethylene and polytrifluorocholoroethylene; vinyl polymers, e.g., polyvinyl chloride; and blends and copolymers thereof. Particularly, suitable polymers for the laminates are polyolefins, including polyethylene, e.g., linear low density polyethylene, low density polyethylene, medium density polyethylene, high density polyethylene and blends thereof; polypropylene, polybutylene; and copolymers as well as blends thereof.
The rubbers or rubber-agents as described herein refer to any natural rubber or synthetic rubber characterized by elasticity, water repellence, and electrical resistance. Natural rubber is typically obtained from the milky white fluid called latex, found in many plants. Synthetic rubbers can be produced from unsaturated hydrocarbons as known in the art.
Non-limiting examples of suitable rubbers or rubber agents suitable for use in the laminates described herein include natural rubber (NR), styrene-butadiene rubber (SBR), isoprene rubber (IR), butadiene rubber (BR), ethylene-propylene rubber (EDM/EPDM), butyl rubber (IIR), chloroprene rubber (CR), nitrile rubber (NBR), and combinations thereof.
The preferred laminates, or their fiber or rubber components, can also include or more agents such as fillers, vulcanizing agents, accelerators, activators, aging protectors, anti-oxidants, anti-ozonants, softeners, oils, plasticizers, pigments, anti-static agents, lubricants, blowing agents, reinforcement agents and combinations thereof.
The laminate, in a preferred form, is a rubberized fabric. Several rubberized fabrics are particularly preferred for use as the laminates described herein. Specifically, these rubberized fabrics can include natural SBR blends, natural rubber, neoprene rubber, and nitrile rubber calendered onto industrial fabrics for a highly durable sheet product. The industrial fabrics can include woven nylons, polyesters, and/or cottons having fabric densities of from about 10 to about 35 oz/yd2; and poly/cotton blends of fabric densities of from about 5 to about 35 oz/yd2. Generally, fabric densities greater than or lesser than these ranges may be used, such as from about 1 to about 50 oz/yd2. In addition, a variety of other fibers including aramid fibers such as Kevlar® and nylon can be used.
The preferred embodiment laminates utilize a rubber component which exhibits at least two, preferably three, and most preferably all four of the following characteristics: (i) Shore A hardness of from about 35 to about 85, (ii) an ultimate tensile strength (or tensile at break) of from about 1000 to about 3000 psi, (iii) a 200% tensile modulus strength of from about 200 to about 1600 psi, and (iv) an ultimate elongation of from about 100% to about 900%.
Shore A hardness is generally measured as follows. The most common instrument for measuring rubber or elastomer hardness is called a Shore durometer. The Shore A durometer has a blunt indenter and a moderate spring force. A spring is used to push a metal indenter into the surface of the material, measuring how far it penetrates. The instrument measures the depth penetration from zero to 0.100 inches. A zero reading on the scale means the indenter is at the maximum depth and a reading of 100 indicates that no penetration was detected. Shore durometers come in a variety of hardness ranges and degrees of automation.
Most materials will resist initial indenture but will yield further over time due to creep or relaxation. Durometer readings can either be taken instantaneously or after a specific delay time, which typically range between 5 and 10 seconds. An instantaneous reading will typically give a higher (or harder) reading than the delayed readings. Delayed readings are more representative of not only the hardness of the material but the resiliency. A weak, less elastomeric material will creep more than a higher strength, more resilient material.
Accurate testing procedures are needed to ensure valid data. To obtain an accurate reading it is desirable to have a flat part surface as well as a part thick enough so the indenter is not affected by the support surface. The usual required thickness is 0.200 inches but hard compounds that experience less deformation can be accurately measured at lower thicknesses.
The “ultimate tensile strength” is a measurement also called “ultimate tensile” or “tensile at break.” In this test, a piece of elastomer is stretched until it breaks. The amount of force needed to break the material is then measured. Units are typically given in pounds per square inch (psi) or megapascals (MPa). Elastomers with high ultimate tensile properties will be more difficult to break by stretching than an elastomer with lower values in this test.
In the “200% tensile modulus” test, the elastomer is stretched and the resistance to the stretching is measured over a range of elongation points. This is often reported as tensile at various percentages of the original length of elastomer, such as 50%, 100% and 300%. An elastomer might have a strong resistance to stretching initially but become weaker as it elongates (called “necking”).
“Ultimate elongation” does not measure how hard or easy the material is to stretch, but simply how far it will stretch before it breaks. This is reported in percentage of original length. Some soft elastomers will stretch to greater than 1000% of their original length before breaking. A soft elastomer thermoplastic elastomer will typically have a much higher value than a hard rigid material.
Several of the particularly preferred rubberized fabrics as described herein are commercially available from the Patch Rubber Company of Roanoke Rapids, N.C. In these rubberized fabrics, one or more of the following fibers can be used as set forth in Tables 1-5:
Examples of other fibers coated with rubber agents are as follows.
As noted, the fibrous layer or preferably, the fabric layer, is coated with the rubber component. After coating, the coating is cured. Table 6 sets forth typical physical and cure properties for a preferred laminate utilizing a nylon fiber and a rubber coating:
Non-limiting examples of other coating compositions can include formulations designated as NSC available from Patch Rubber Company. Details of these formulations are set forth in Table 7.
Preferably, the laminates used in the outer cover layer of the sports balls described herein include the fiber component and the rubber component as the primary and exclusive agents in the ball outer layer. That is, the laminates do not contain other agents or polymers disposed on, or within, the fiber component. The laminates can consist essentially of the fiber component and the rubber component, but may also include minor proportions of ancillary agents. In certain embodiments, the laminate can consist solely of the fiber component and the rubber component. In other embodiments, the laminates described herein are free of conventional coating agents such as polyurethanes, and so, the processing and disposal concerns otherwise associated with such materials are avoided.
The laminates described herein can be utilized in nearly any sports ball where increased grippability or enhanced frictional characteristics of an outer surface are desired. Preferably, the laminates are utilized in inflatable sports balls. Non-limiting examples of such inflatable sports balls include basketballs, footballs, soccer balls, and volley balls.
It is also contemplated to provide one or more logos, indicia, or other text or symbols along the exterior surface of the sports balls disclosed herein. For example, a logo or trademark associated with the manufacturer or supplier of the sports ball could be embossed or otherwise marked along the outer surface so as to be visible or evident to consumers. In certain embodiments, it may be desirable to form a depression or raised projection in the outer surface of the sports ball to denote the particular logo or indicia.
A preferred technique for fabrication of the laminate cover material which is used in the sports balls described herein is to form an impregnation of fibers with the rubber component. The material subsequently undergoes an extraction process to give the material a soft feel. Alternately, the fibrous layer is coated on either one side or both sides with the rubber component.
One preferred process for preparing the sports ball laminate material includes the formation of a substrate which is prepared by providing a mat of fibers in a thickness appropriate to result in a final cover material thickness of about 0.5 mm to about 3 mm, more preferably 0.8 mm to about 2.0 mm and most preferably about 1.2 mm.
The mat can be dipped in a solvent for a period of time sufficient to dissolve off any outer shell of the fiber (if using a bi-component fiber), thereby exfoliating the central fibers. At the same time, additives, if used, soften the material. Next, the mat of extracted fibers is coated with the rubber component. The impregnated sheet material is dried.
In one embodiment, basketball is provided having the construction noted above, and specifically, in
In another embodiment, a football is assembled in the following manner. The football cover panels containing the laminate material along their outer surface are cut in a generally oval shape and are coupled together at their edges by stitches and positioned over a bladder or carcass. Four essentially similarly shaped, generally oval shaped panels are normally utilized with the panels in abutment along their edges. Their edges are in-turned and stitched. The liner is formed from a plurality of components having the same shape and size as the cover panels. The liner components are stitched to the cover panels along their peripheries. The edges of the panels and liner components are then stitched together along their edges forming seams and creating a football-shaped shell for receiving a pre-molded bladder. The stitching is made while the panels and liner are inside out. A central extent along one seam is not stitched to thereby from an opening through which the bladder may be inserted during fabrication. A tongue and two patches are then sewn to the panels and liner in a conventional manner, with the patches spanning the unstitched opening. The tongue is sewn to a cover panel and liner along a short extent offset slightly from the patches. The panels and liner components are then turned inside out and the bladder is inserted. The opening is then closed by lacing with the tongue having an enlarged portion located between the bladder and the patches. The structure of the lacing and closure are further described in U.S. Pat. No. 5,098,097, the contents of which are incorporated herein by reference. A volleyball, softball, or other game ball of the disclosure can be assembled in a conventional manner.
Pebbling or other surface features may be produced by techniques known in the art such as by embossing. Alternately, or in addition, one or more cushioning layers can also be incorporated under or beneath the fiber-containing rubber laminate described herein.
In all of the noted embodiments described herein, it is generally preferred to vulcanize or cure the rubber fiber-containing outer layer of the sports ball. Vulcanizing can be performed by techniques known in the art generally involving heating the material to be vulcanized for a sufficient time and/or at a sufficient temperature. In one aspect, it is preferred to vulcanize concurrently with a pebbling operation.
The exemplary embodiment has been described with reference to the preferred embodiments. Obviously, modifications and alterations will occur to others upon reading and understanding the preceding detailed description. It is intended that the exemplary embodiment be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.
