US 20060293132 A1
Disclosed is an inflatable sports ball with a plurality of layers. The sports ball may have an exterior layer, a padded layer, and a bladder. The padded layer may be configured to provide increased grip and feel characteristics for the user. The padded layer can be formed from a foamed styrene butadiene rubber. This disclosure is intended to apply to inflatable footballs, and the like.
1. A football comprising:
an inflatable bladder;
an outer cover; and
a padded layer disposed between the bladder and the outer cover, the padded layer including a foamed styrene butadiene rubber.
2. The ball of
3. The ball of
4. The ball of
5. The ball of
6. The ball of
7. The ball of
8. The ball of
9. A football comprising:
an inflatable multi-layer bladder;
a water resistant liner disposed on the bladder;
a padded layer disposed on the liner, the padded layer including a styrene butadiene rubber; and
a cover layer disposed on the padded layer.
10. The ball of
11. The ball of
12. The ball of
13. The ball of
14. The ball of
15. An inflatable sports ball comprising:
an inflatable multi-layer bladder;
a multi-layer water resistant liner having a first inner layer and a second outer layer, the liner disposed on the multi-layer bladder such that the first inner layer contacts the bladder;
a padded foam layer disposed on and bonded to the second outer layer of the liner, the padded foam layer including a butadiene rubber; and
a cover layer disposed on the padded layer.
16. The sports ball of
17. The sports ball of
18. The sports ball of
19. The sports ball of
20. The sports ball of
The present disclosure is generally related to the field of inflatable sports balls or game balls, including footballs and the like. More particularly, this disclosure relates to improving the grip and feel characteristics of the balls.
the modern game of American football utilizes a football in the shape of a prolate spheroid. Covers of footballs are now commonly formed from leather, rubber, or other materials. It is important that the cover of the football be formed in a manner that facilitates the handling and feel of the ball.
The outer surface of a modern football typically includes a pebble texture that improves the ability to grip the ball. Maintaining the normal texture, feel, and grip of the football is important in preserving the character of the game. Any reduction in a player's ability to properly grasp the football can limit that player's performance. A player must maintain the ability to throw, catch, run with, and/or hold on to, the football regardless of the conditions. During game conditions, players' perspiration, weather conditions, and other factors can negatively affect the players' ability to grasp the football.
When a football (or other inflatable sports ball) is manufactured, a bladder is generally formed. The bladder is generally molded under pressure and heat to form the desired size and shape. Once the bladder is shaped (depending on the material used for the bladder), the bladder may be wound with a lining made of nylon, cloth, or other material. The wound bladder may then be dipped in latex, adhesive, or other material.
Depending on the type of ball produced, the bladder may interact with the rest of the athletic ball in a variety of ways. As a non-limiting example, the exterior of a football may be simultaneously constructed leaving an opening by which to insert the bladder. Once the bladder in inserted into the football, the laces may be applied to secure the bladder within the football.
Regardless of the type of ball being produced, the ability to grip and control the ball is universally important. One method of enhancing the grip and feel characteristics of a football is embossing the football with a first tactile pattern and a second tactile pattern. While this method may somewhat improve a player's ability to grip the football, its effectiveness is generally limited by the materials used, and the size and shape of the tactile pattern.
One challenge is to produce a football that has improved gripping and tactile characteristics. Similar considerations apply to the production of other types of inflatable game balls, such as, for example rugby balls, and the like. Consequently, an enhancement of a traditional football that will improve the feel and the ability to grip the football, without compromising the quality of the construction process, is needed.
Attempts have been made to improve gripping characteristics of a sports or game ball by incorporating a layer of padding under the cover of the ball. U.S. Pat. No. 3,119,618 describes a game ball, such as a basketball or football having a sponge layer disposed between a leather cover and an inner carcass. The sponge layer is provided to facilitate gripping the ball. U.S. Pat. No. 4,462,590 describes inflatable game balls, and specifically including footballs, having a padding layer disposed between a leather cover and a multi-layer bladder. Polyurethane foam can be used for the padding layer. U.S. Pat. No. 4,660,831 is directed to inflatable game balls including footballs having a padding layer of neoprene foam disposed between a leather cover and a liner assembly, which liner surrounds an innermost bladder. U.S. Pat. No. 6,206,795 describes a basketball having a cushion layer underneath an outer cover layer. The cushion layer is noted as being a foamed material. More recently, U.S. Patent Application 2004/0213984 discloses a game ball that includes a polymer foam layer for enhancing the overall pliability and cushioning of the ball. The foam layer can be formed from a variety of polyolefin foams that are processed with a nitrogen blowing agent. Examples of the foams include low density polyethylene, high density polyethylene, polypropylene, and ethylvinyl acetate (EVA).
Although satisfactory in many respects, prior ball constructions utilizing padding or cushion layers have suffered from being relatively costly or difficult to produce, at least on a large commercial scale, or simply failed to provide the gripping and playing characteristics desired by consumers. Accordingly, a need remains for a layer and construction strategy for an inflatable sports ball that is economical, easily manufactured, and provides an attractive overall feel and good playability.
The present disclosure provides, in various embodiments, an inflatable sports ball, such as a football, comprising an inflatable bladder, an outer cover, and a padded layer between the bladder and the outer cover. The padded layer includes a foamed butadiene rubber material. Such a ball exhibits improved feel and playability characteristics.
In accordance with another embodiment, the disclosure relates to an inflatable sports ball comprising an inflatable multi-layer bladder, a water resistant liner disposed on the bladder, a padded layer disposed on the liner, and a cover layer disposed on the padded layer. The padded layer includes a styrene butadiene rubber.
In yet another embodiment, the present disclosure provides an inflatable sports ball comprising an inflatable multi-layer bladder. The ball also comprises a multi-layer water resistant liner having a first inner layer and a second outer layer. The liner is disposed on the multi-layer bladder such that the first inner layer contacts the bladder. The ball also comprises a padded foam layer of a butadiene rubber disposed on and bonded to the second outer layer of the liner. The ball further comprises a cover layer disposed on the padded layer.
There has thus been outlined, rather broadly, some of the more important features of the sports ball disclosed herein in order that the detailed description thereof that follows may be better understood. There are, of course, additional features of the disclosure that will be described hereinafter and which will form the subject matter of the claims appended hereto.
In this respect, before explaining at least one embodiment of the sports ball disclosed herein in detail, it is to be understood that the disclosure is not limited in this application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The disclosed sports ball is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of descriptions and should not be regarded as limiting.
As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present development. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the disclosure.
Many aspects of the present disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.
The present development stems, at least in part, from a discovery that the incorporation of a layer of a foamed styrene butadiene rubber in an inflatable sports ball, such as a football, results in the ball exhibiting surprisingly good gripping and playing characteristics. In addition, the incorporation of such a material can be readily and economically performed, thereby suggesting that the sports balls disclosed herein will have widespread commercial appeal.
Various aspects of the athletic or sports ball with a padded construction having been summarized above, reference will now be made in detail to the description of the representative assembly illustrated in the drawings. While the present disclosure will describe the sports ball with padded construction in connection with these drawings, there is no intent to limit it to the embodiment or embodiments disclosed therein.
Footballs generally include at least one of two different covers: leather, and composite. Leather is generally used by professional athletes, and is considered best for grip, feel, and control. One disadvantage of a leather cover on a football is that the ball can be damaged if scraped against a hard surface like asphalt or concrete.
Composite footballs on the other hand generally attempt to simulate the look and feel of a real leather ball. They can be made of polyurethane (PU) or polyvinyl chlorides (PVC), natural or synthetic rubbers, synthetic composites, microfiber composites, etc. Some advantages of a composite football are that they are durable and less expensive than a leather ball.
There are many variations of synthetic leather used in the construction of the outer layer 20 of sports balls. Some examples include AI-2000, Japanese Teijin Cordley, Microfiber, English Porvair, Korean Ducksung, Leather Art Pakistan Synthetic Leather, and PVC (poly vinyl chloride). As a non-limiting example some of the best soccer balls used in competition and by professionals are produced by using AI-2000, Cordley, Ducksung, Mircofiber or other types of PU synthetic leather. Alternatively, promotional or practice balls can be constructed with polyvinyl chloride (PVC) or rubber (molded or stitched) covers.
While the materials used in constructing the outer layer 20 of any sports ball is important, so is the arrangement of those materials. Generally, sports balls include a plurality of panels. The panels are the different segments that make up the outside covering of the ball. The number of panels varies depending on the type and design of the ball. Panels can be stitched, glued, or thermally molded together.
Usually, the outer layer 20 of high quality balls is stitched together with a polyester or similar thread. Five-ply twisted polyester cord is the material of choice in stitching together an athletic ball. Hand sewn balls have tighter and stronger seams. Kevlar® reinforced polyester stitching may also be used on some balls. High-end balls are usually hand-stitched, while most mid-priced balls are machine-stitched. Lower-end balls generally have the panels glued together onto the lining. These offer a harder feel and are generally less expensive than stitched balls. Furthermore, most basketballs, including high end balls, are produced utilizing this process.
Bladder layer 22 in the sports ball is generally designed to retain air. The bladder 22, when properly inflated, provides the primary resilience to the finished sports ball. Bladder 22 is usually made from latex or butyl rubber and fitted with a valve stem (not shown) for introducing air into the ball as inflated pressure to the structure. Compared to latex bladders, butyl rubber bladders retain air for longer periods of time. Latex bladders, on the other hand tend to provide better surface tension. However, butyl rubber bladders offer the excellent combination of contact quality and air retention.
Natural latex rubber bladders usually offer the softest feel and response, but do not provide the best air retention. Latex rubber is a material with multiple micro-pores. Micro-pores are tiny holes that slowly allow air to escape. Balls with natural rubber bladders need to be re-inflated (at least once a week) more often than balls with butyl bladders (stay properly inflated for weeks at a time) due to these micro-pores.
Some balls use carbon-latex bladders in which the carbon powder helps to close many of the micro pores. Carbon latex bladders retain air longer than bladders made from latex rubber. Carbon can be added to the latex to plug some of the microscopic holes that are in pure latex bladders. Latex bladders are used in balls because latex gives proper bounce, feels softer, and provides same angle re-bounce characteristics. Butyl bladders on the other hand, offer an excellent combination of feel and air retention and can be found in most middle to upper priced balls. Some manufacturers also use bladders made from polyurethane.
A bladder layer 22 is located inside outer layer 20, and is constructed to accept and retain air. As recited above, the bladder layer 22 can be constructed of a thermoplastic, latex, butyl, or other similar material capable of retaining air. The bladder layer 22 can be of appropriate thickness as to reasonably protect against loss of air due to puncture, temperature change, or other foreseeable occurrences.
A significant feature of the present disclosure relates to the unique gripping characteristics and beneficial feel that result from the use of a particular padding layer and construction strategy for the sport balls described herein. In one aspect, the various preferred embodiment balls utilize a padded layer that is formed from styrene butadiene rubber (SBR). SBR is known for its excellent impact strength, good resilience, tensile strength and abrasion resistance. The material maintains flexibility at very low temperatures.
Styrene butadiene rubber is a synthetic rubber. SBR typically contains 0-50% and usually about 20-25% styrene. The basic structure of SBR is shown below.
SBR is primarily produced by two techniques, emulsion polymerization to form ESBR (or sometimes denoted as E-SBR) and solution polymerization to form SSBR (or sometimes denoted as S-SBR).
ESBR polymerization is based on free radicals that attack the unsaturation of the monomers, causing addition of monomer units to the end of the polymer chain, whereas the basis for SSBR is by use of ionic initiators.
Free-radical initiation of emulsion copolymers produces a random polymerization in which the trans/cis ratio cannot be controlled. The nature of ESBR free-radical polymerization results in the polymer being heterogeneous, with a broad molecular weight distribution and random copolymer composition. The microstructure is not amenable to manipulation, although the temperature of the polymerization affects the ratio of the trans to cis forms somewhat.
In solution-based polymerization, use of the initiating anionic species allows control over the trans/cis microstructure of the diene portion of the copolymer. In solution, a typical catalyst allows the 1,2 content to be changed with certain modifying agents such as ethers or amines.
Advantages of emulsion polymerization of SBR include the following: (1) high molecular weight polymer at high production rates; (2) relatively low viscosity of the latex formed to give good heat transfer of the generated exotherm; (3) good control of the polymerization temperature; (4) ease of removing unreacted monomers and their recovery; and (5) ease of processing the finished latex into dry polymer product.
Although the various preferred embodiment sport balls include both forms of SBR, it is generally preferred to utilize a padded layer of E-SBR.
E-SBR is commercially available in Mooney viscosities ranging from about 30 to about 120 (ML1+4@125 C). Lower Mooney viscosity E-SBR grades band more easily on a mill, incorporate fillers and oil more readily, show less heat generation during mixing, are calendered more easily, shrink less, give higher extrusion rates and have superior extrudate appearance than the higher Mooney viscosity grades. On the other hand, the high Mooney viscosity SBR's have better green strength, less porosity in the vulcanizate, and accept higher filler and oil loadings.
As the molecular weight of the SBR increases, the vulcanizate resilience and the mechanical properties, particularly tensile strength and compression set, improve. The processability of SBR improves as its molecular weight distribution broadens. Formation of high molecular weight fractions with the increase in the average molecular weight can however, prevent improvements in the processability. This is due to the fact that the tendency for gel formation also increases at higher molecular weights.
In addition to the polymer viscosity, polymerization temperature also plays an important role in shaping the processability of the resulting SBR material. E-SBRs produced at low polymerization temperatures have less chain branching than those produced at higher temperature. At an equivalent viscosity, cold polymerized E-SBR is normally easier to process than hot polymerized E-SBR, and this applies particularly to a better banding on mills, less shrinkage after calendaring, and a superior surface for certain layered applications. Hot rubbers give better strength because they have more chain branching.
The styrene content of most emulsion SBR varies from 0% to 50%. The percent styrene of most commercially available grades of E-SBR is about 23.5%. In vulcanizates of SBR, as styrene content increases, dynamic properties and abrasion resistance decrease while traction and hardness increase.
Polymerization temperature also affects the microstructure of E-SBR. In the cold polymerized E-SBRs, the butadiene component has, on average, about 9% cis-1,4, 54.5% trans-1,4, and 13% of vinyl-1,2 structure. At a 23.5% bound styrene level, the glass transition temperature, Tg, exhibits a low resilience and poor abrasion resistance with an excellent wet traction.
The emulsifier remains in the rubber after coagulation can also have an influence on the processability. Rosin acid emulsifiers impart better knitting, tack and adhesion to the SBR polymer. Generally, polymers emulsified with rosin acid have better extrusion rates, slower cure rates, poorer heat resistance and can cause mold fouling and polymer discoloration. Fatty acid emulsified SBR polymers generally have less tack, faster curing, and high tensile properties. A compromise of the above properties is obtained by using a mixed rosin acid-fatty acid emulsifier system.
Since SBR lacks the self-reinforcing qualities of natural rubber due to stress induced crystallization, gum vulcanizates of SBR have lower tensile properties. The tensile property of E-SBR vulcanizates depends in great measure on the type and amount of filler in the compound. Cured gum stocks have only 2.8 to 4.2 MPa tensile strength, while fine particle carbon black loadings can produce tensile strength of 27.6 Mpa. Though the compression set of some of the common E-SBR compounds is high, by proper compounding and blending, it is possible to obtain E-SBR vulcanizates with a low compression set.
The SBR padded layers described herein are in the form of a foam, i.e. they can be characterized by having numerous hollow cells. The foamed structures are either open celled or closed cell, however an open cell structure is generally preferred. The geometry and size of the cells can also vary.
SBR materials suitable for use in the padded layers described herein are commercially available from a variety of sources such as Dow Chemical, Midland, Mich.; Ameripol Synpol Corp., Port Neches, Tex.; Bayer Rubber Inc., Sarnia, Ontario, Calif.; DSM Copolymer Inc., Baton Rouge, La.; and Goodyear Tire & Rubber Co., Houston, Tex.
A padded layer 24 can be bonded adjacent outer layer 20 to help improve the grip and feel characteristics of the ball 12. As noted, a preferred type of foam that may be used to construct the padded layer 24 is styrene butadiene rubber (SBR). Also preferred are butadiene rubbers, also known as polybutadiene rubbers. SBR is a member of this class of rubbers.
A water resistant liner layer 26 can reside adjacent padded layer 24 and may be constructed of a suitable material to prevent the intrusion of water into the center regions of the sports ball. As is evident, the water resistant liner layer 26 may be incorporated into padded layer 24, as many of the properties performed by the water resistant liner layer 26 may be achieved by the appropriate material in the padded layer 24. Preferably, the liner is a multi-layer or multiple ply liner assembly. The preferred liner assembly can include an inner layer that is positioned on, and preferably contacts, a bladder disposed thereunder. The preferred liner assembly can also include an outer layer that is adjacent to the inner layer, and which preferably contacts the padded layer.
In football 12, a bladder layer 22 is located adjacent water-resistant liner layer 26, and is constructed to accept and retain air. As recited above, the bladder layer 22 can be constructed of a thermoplastic, latex, butyl, or other similar material capable of retaining air. The bladder layer 22 can be of appropriate thickness as to reasonably protect against loss of air due to puncture, temperature change, or other foreseeable occurrences. As is evident, the bladder layer 22 need not reside adjacent water resistant liner layer 26. The bladder layer 22 need only be positioned to accept and retain air for football 12. In certain aspects, the bladder is a multiple layer bladder assembly and includes two, three, four, or more layers. One or more of the layers is preferably formed from a thermoplastic PU.
The various padded layers described herein are incorporated in the sports balls such that the layer exhibits a thickness of from about 0.65 mm to about 6.4 mm, preferably from about 1.0 mm to about 3.0 mm, and more preferably from about 1.5 mm to about 2.0 mm. Moreover, the padded layers have a hardness of about Shore A 15. However, it will be appreciated that the various preferred embodiments described herein include the use of padded layers having thicknesses and hardnesses greater than or less than these values.
The foamed padded layer, having cells defined therein can be formed as follows. The cells are typically produced by adding a blowing agent to the raw material. Different concentrations of blowing agent will change the density of the molded cellular layer. Such blowing agents are exemplified by Celogen TSH available, from Uniroyal Chemical, Middlebury, Conn. USA.
Although it is possible to foam the material, e.g. the SBR composition, directly in-situ during manufacture of the sports ball, the present invention also includes production methods in which panels or layers of foamed, i.e. expanded, material be incorporated within the ball after foaming or expansion.
Once the bladder is added to the padded cover, the ball is then in condition for the application of decals, paint or other decorative or informative markings. The balls have the same size, weight, circumference as “regulation” and other (i.e., intermediate, youth, etc.) balls. The balls may be used for both indoor and outdoor play.
The various preferred embodiment sports balls described herein can be formed according to known methods. Representative manufacturing techniques and other details for forming footballs and other sports balls are described in U.S. Pat. Nos. 4,928,962; 5,069,935; 5,181,717; 5,669,838; and 6,123,632.
Representative manufacturing techniques and other details for forming soccer balls and other sports balls are described in U.S. Pat. Nos. 3,927,882; 4,187,134; 4,333,648; 5,752,890; 5,580,049; and 6,503,162.
Representative manufacturing techniques and other details for forming basketballs and other sports balls are described in U.S. Pat. Nos. 5,681,233; 6,520,877; 3,405,018; 5,310,178; and 5,741,195.
Representative manufacturing techniques and other details for forming volleyballs and other sports balls are described in U.S. Pat. Nos. 3,506,265; 5,542,662; 6,413,177; and 4,856,781.
All documents cited herein are, in relevant part, incorporated herein by reference; the citation of any document is not to be construed as an admission that it is prior art with respect to the present invention.
It should be emphasized that the above-described embodiments of the present disclosure, particularly, any “preferred” embodiments, are merely possible examples of implementations, merely set forth for a clear understanding of the principles of the sports balls. Many variations and modifications may be made to the above-described embodiment(s) of the sports balls without departing substantially from the principles thereof. All such modifications and variations are intended to be included herein within the scope of this disclosure.