Classifications

• • A—HUMAN NECESSITIES
  • A63—SPORTS; GAMES; AMUSEMENTS
  • A63B—APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT
  • A63B37/00—Solid balls; Rigid hollow balls; Marbles
  • A63B37/12—Special coverings, i.e. outer layer material
• • A—HUMAN NECESSITIES
  • A63—SPORTS; GAMES; AMUSEMENTS
  • A63B—APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT
  • A63B37/00—Solid balls; Rigid hollow balls; Marbles
  • A63B37/0003—Golf balls
• • A—HUMAN NECESSITIES
  • A63—SPORTS; GAMES; AMUSEMENTS
  • A63B—APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT
  • A63B37/00—Solid balls; Rigid hollow balls; Marbles
  • A63B37/0003—Golf balls
  • A63B37/0023—Covers
  • A63B37/0024—Materials other than ionomers or polyurethane
• • A—HUMAN NECESSITIES
  • A63—SPORTS; GAMES; AMUSEMENTS
  • A63B—APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT
  • A63B37/00—Solid balls; Rigid hollow balls; Marbles
  • A63B37/0003—Golf balls
  • A63B37/0023—Covers
  • A63B37/0029—Physical properties
  • A63B37/0033—Thickness
• • A—HUMAN NECESSITIES
  • A63—SPORTS; GAMES; AMUSEMENTS
  • A63B—APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT
  • A63B37/00—Solid balls; Rigid hollow balls; Marbles
  • A63B37/0003—Golf balls
  • A63B37/005—Cores
  • A63B37/0051—Materials other than polybutadienes; Constructional details
  • A63B37/0053—Thread wound
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
  • C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
  • C08L23/04—Homopolymers or copolymers of ethene
  • C08L23/08—Copolymers of ethene
  • C08L23/0846—Copolymers of ethene with unsaturated hydrocarbons containing atoms other than carbon or hydrogen
  • C08L23/0869—Copolymers of ethene with unsaturated hydrocarbons containing atoms other than carbon or hydrogen with unsaturated acids, e.g. [meth]acrylic acid; with unsaturated esters, e.g. [meth]acrylic acid esters
  • C08L23/0876—Salts thereof, i.e. ionomers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2205/00—Polymer mixtures characterised by other features
  • C08L2205/02—Polymer mixtures characterised by other features containing two or more polymers of the same C08L -group
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2310/00—Masterbatches

Definitions

• covers which are formed from polymeric materials.
• the traditional golf ball having a cover formed from Balata rubber should-be noted.
• the physical properties, and in particular, t ' he "feel" of this Balata cover when struck with a golf club became the standard of the industry.
• golf balls have incorporated covers which are formed from synthetic polymeric materials such as polyolefins and in particular, polyethylene, polyurethanes and ionic copolymers of olefins.
• the latter mentioned ionic copolymers of olefins were commercially introduced in the mid 1960's by E. I.
• Surlyn Du Pont De Nemours & Co., Inc., Wilmington, Delaware and sold under the trademark "Surlyn.” Cover compositions which are based on Surlyn resins have become extremely popular and are highly advantageous in that the resulting covers are extremely -cut and abrasion resistant. Golf balls incorporating Surlyn resin covers are commonly known in golfing circles to be more cut resistant than Balata covered balls. These Surlyn covered golf balls have achieved widespread consumer acceptance. About sixty percent of the golf balls sold in the United States during 1976 incorporated Surlyn covers. Golf balls incorporating Surlyn covers are generally described in U. S. Patent 3,454,280 issued July 8, 1969.
• Surlyn resin as sold by E. I. De Pont De Nemours & Co. , Inc. contain zinc or sodium ions.
• a plurality of Surlyn resins of varying physical properties are sold by E. I. De Pont De Nemours & Co., Inc. The physical properties of these various resins are described in technical bulletins which are readily available from E. I. De Pont De Nemours & Co., Inc.
• the principal Surlyn resins which are useful in this invention as golf ball cover materials are Surlyn A 1605 and Surlyn A 1557. Mixtures of various Surlyn resins as cover stock mate ⁇ rials are likewise highly advantageous. Suitable mixtures for use as cover stock materials are described in detail in U. S. Patent 3,819,768 issued June 25, 1974.
• Surlyn resins While being extremely advantageous due to their cut in abra ⁇ sion resistance have one noteable disadvantage as a golf ball cover stock material, namely that the feel of the ball when struck by a golf club is significantly different than that of a traditional Balata covered golf ball.
• an audible sound is emitted. This sound is generally referred to as the click of a golf ball.
• the click of Surlyn covered golf balls is significantly different than the click of .Balata covered golf balls.
• the ability to incorporate back spin onto a golf ball is related to the extent to which a golf ball deforms when ' it is struck with a golf club. Because tradi ⁇ tional Balata covers are more deformable it is easier to im ⁇ part spin to these traditional balls. In contrast, Surlyn covered golf balls due to the nature of the cover are not as deformable as Balata covered balls and hence it has been more difficult to impart a sufficient degree of back spin to these balls. This control advantage will be discussed in greater detail herein below.
• a standard which is generally referred to as the coeffi ⁇ cient of restitution is one of the criteria useful in judging the rebound characteristics of a golf ball.
• the nature of the cover stock has substantial bearing on the coefficient of restitution of any given golf ball.
• one skilled in the art can alter the coefficient of restitution of a given golf ball to a much greater degree than was possible utilizing the covers of the prior art.
• the ramifications of the coefficient of restitution in rela ⁇ tion to the subject invention will be described in greater detail herein below.
• Figure 1 is a front view of a conventional golf ball
• Figure 2 is a sectional view through line 2-2 of Figure 1 showing the cover of this invention on a solid core golf ball;
• Figure 3 shows the cover of this invention on a wound core golf ball
• Figure 4 is a sectional view showing one embodiment of the cover of this invention wherein said cover incorpor ⁇ ates non-cellular skins
• Figure 5 shows another embodiment of this invention wherein the composite cover is essentially cellular; and Figure 6 illustrates still another embodiment of this invention wherein the cover incorporates areas of varying cellular density.
• Figure 7 illustrates the superior high speed impact properties of the golf ball of the subject invention.
• Figures 8 and 9 illustrate the superior low speed impact properties of the golf ball of this invention.
• Figure 10 is a photo micrograph showing a cross sec ⁇ tion of a representative golf ball cover in accordance with this invention wherein said cover has well defined inner and outer skins.
• Figure " II is a photo micrograph showing a cross sec ⁇ tion of a representative golf ball cover in accordance with this invention wherein said cover has no inner skin and a minimal outer skin.
• the subject invention relates to the use of cellular material as cover stock for conventional golf ball centers.
• the cellular cover stock of this invention can have a uniform cellular cross section, a varying cellu- lar cross section or be incorporated with one or more non- cellular skins.
• the cellular cover stock of the subject invention can be formed from any foamable, natural or synthetic polymeric material.
• Such materials are known in the art and are generally prepared with blowing agents, nucleating agents, and other additives as necessary to create the desired structures.
• thermoplastic materials are generally preferred.
• thermosetting resins can likewise be used in accordance with this invention. Typical, but not limitative of the properties desirable for the resin are good flowability, moderate stiffness, high abrasion resis ⁇ tance, high tear strength, and good mold release among others.
• Preferred polymeric materials for use in accordance with this invention are ionomer resins comprising a copoly- mer of ethylene and an unsaturated monocarboxylic acid which is available under the trademark Surlyn from E. I. Du Pont De Nemours &. Company of Wilmington, Delaware.
• the cellular cover in question is formed from either a zinc or sodium ionic copolymer of ethylene or mix ⁇ tures thereof.
• the sodium copolymer being sold by the E. I. De Pont De Nemours & Co., Inc., under the trademark Surlyn 1605, the zinc copolymer being sold under the trade ⁇ mark Surlyn 1557.
• Figure 1 illustrates a standard golf ball structure 2 which incorpo ⁇ rates a plurality of conventional dimples 4. Dimples 4 are molded into the cover material which is the subject matter of this invention. In this patent application when referred to generically golf ball 2 is meant to include golf balls having solid or wound centers.
• golf ball 2 incorporates a solid center 6 which is in turn encapsulated by a cellular cover 8.
• Center 6 generally comprises a highly cross linked polybutadiene sphere.
• the technology for producing solid centers such as center 6 is generally known in the prior art and does not constitute part of the subject invention.
• golf ball 2 incorporates a wound center 10 which is in turn encapsulated by a cellular cover 8.
• would center 10 generally, comprises the central sphere not shown over which is wound an extended length of an elastomeric thread in order to produce a sphere of a given size.
• Figures 4, 5 and 6 represent three distinct embodiments of the subject invention. While these three distinct embodi ⁇ ments are illustrated on a solid center which has been given a common disignation 6, it is understood that the embodiments as illustrated in Figures 4, 5 and 6 can likewise be incorpo- rated on wound center such as center 10 of Figure 3.
• Figure 4 represents a preferred embodiment of this inven ⁇ tion for use in conjunction with solid center.
• cover 12 incorporates a central cellular stra ⁇ tum 14 which is sandwiched between two non-cellular skins 16 and 18.
• Non-cellular skins 16 and 18 are formed in situ by varying the process parameters wherein cover 12 is molded onto center 6.
• Skins 16 and 18 can be altered and formed by a plural ⁇ ity of techniques, for example, skins 16 and 18 can be formed by varying the temperature of the mold during the initial stages of the injection molding process and by vary ⁇ ing other parameters, such as melt temperatures, injection time, injection speed, injection pressure, nozzle type, gating, venting, holding pressure, holding time, shot weight, blowing agent concentration, nucleator concentration, poly ⁇ meric composition, mold surface treatment and mold lubricant.
• melt temperatures injection time, injection speed, injection pressure, nozzle type, gating, venting, holding pressure, holding time, shot weight, blowing agent concentration, nucleator concentration, poly ⁇ meric composition, mold surface treatment and mold lubricant.
• FIG. 5 illustrates another embodiment of this inven ⁇ tion wherein cover 20 incorporates an essentially uniform cellular structure.
• cover 20 is again molded over.center 6.
• Figure " 6 represents still another embodiment of this invention wherein cover 22 is molded over core 6.
• Cover 22 incorporates a central stratum 24 which is sandwiched between a pair strata 26 and 28.
• the central stratum 24 has an apparent density which is less than that of strata 26 and 28.
• strata 26 and 28 have a greater apparent density than that of central stratum 24.
• the apparent density of cover 22 will vary.
• the respective apparent den- sities of strata 24, 26 and 28, can be varied by one skilled in the art by altering the process parameters as discussed above wherein cover 22 is molded onto center 6.
• the solid cores for use in accordance with this inven ⁇ tion are approximately 1.50" diameter.
• all golf balls are 1.680" - 1.690" in diameter. Therefore, it can be seen that the cover thickness of the ball of this invention is approximately one-half the difference between the center size and the finished ball size,
• cover thicknesses of this size are generally advantageous and functional when used with this invention. Naturally, it would be possible to utilize .larger diameter centers and hence minimize the cover thickness. Generally, it could be said that the cover thickness should not decrease to a point beyond which func ⁇ tional foaming is impossible. While full parameters of the cover thickness have not been explored, it generally appears as though functional foaming cannot be achieved if the cover thickness decreases beyond .060".
• the diameter of wound centers is normally greater than that of a solid center.
• the wound center is compressed with the net result that the effective size in the finished cen ⁇ ter is similar to the 1.50" dimension discussed above relative to a solid center.
• Balata or gutta percha is an example of natural polymeric material adapted for use in accordance with this invention.
• Homopolymeric and copolymeric substances such as (1) vinyl resins formed by the polymerization of vinyl chlorides or by the copolymerization of vinyl chlorides with unsatu- rated polymerizable compounds, e.g., vinyl esters; (2) poly ⁇ olefins such as polyethylene, polypropylene, polybutylene, transpol isoprene, and the like, including copolymers of polyolefins; (3) polyurethanes such as are prepared from polyols and organic polyisocyanates; (4) polyamides such as polyhexamethylene adipamide; (5) polystyrene, high impact polystyrene styrene acrylonitrile copolymer and ABS, which is acrylonitrile, butadiene styrene copolymers; (6) acrylic resins as exemplified by the copolymers of methylmethacrylate, acrylonitrile, and styrene, etc.; (7)
• compositions of this invention may also be used. It is within the purview of this invention to add to the cover compositions of this invention compatible materials which do not affect the basic novel characteristics of the composition of this invention. Among such materials are coloring agents, including dyes and pigments, fillers and similar additives. Additives such as antioxidants, anti ⁇ static agents, and stabilizers may also be added. The upper limit of the quantity of additives is usually about 5 weight percent of the product.
• the golf ball cover material of this invention can be applied to a center in any standard manner.
• the cover material can be injected molded directly around a pre- positioned center or two half shells of a cover can be formed from the cover material of this invention. These half shells are then positioned around a center and fused together in such a manner as to form a finished golf ball.
• the cover com- position of the subject invention can utilize many standard manufacturing techniques to form finished golf balls. Nat ⁇ urally the technique utilized must provide physical conditions sufficient to make foaming possible.
• the cover material of this invention is applied over a standard center in a conventional fashion.
• Centers of either the solid or wound type can be used in accordance with this invention.
• a thread like material is wound either over a solid core or a spherical shell which is liquid filled.
• the thread like material which is wound around this small core is either in a thread or tape form.
• the solid center balls these are balls wherein the center generally comprises a sphere which is formed from a resilient polymeric material. Because the center material is not an integral part of this invention it is not thought that a detailed discussion of center materials is necessary. However it can be said that the cover material of the subject invention can be utilized in conjunction with any standard golf ball center.
• the golf ball cover of the sub- ject invention can be used as a means of altering or regu ⁇ lating the coefficient of restitution.
• the coefficient of restitution of a golf ball is generally indicative of the resiliency of the ball in question, hence indicative of the distance the ball will travel when struck with a golf club. Both the center and the cover contribute to the coefficient of restitution; however, for purposes of this invention we are concerned solely with the coefficient of restitution, as it is affected by the cover material.
• the coefficient of restitu ⁇ tion is generally measured by propelling a finished golf ball against a hard surface at a fixed velocity. After the ball has rebounded from the surface its velocity is again measured. The ratio of the rebound velocity over the initial velocity is the coefficient of restitution.
• the coefficient of restitu ⁇ tion is directly related to the resiliency of a golf ball and how far it will travel when struck by a golf club, all other variables being constant.
• the resiliency of a golf ball is regulated by the United States Golf Association via a test which is generally referred to as the Initial Velocity test.
• Initial Velocity test In this test, a golf ball is struck by a rotating club face. The rotating club face is turning at a speed of approximately 146 ft. per second. Once struck by this club face, the velocity of the ball is measured as it passes through two light screens which are positioned forward of said club face.
• the maximum prescribed limit for a golf ball which is tested in this manner is 255 ft. per second at 75°F. This upper limit standard of 255 f.p.s. cor- responds to a coefficient of restitution of approximately .795.
• the subject cover material is particularly advantageous in that in using this invention golf balls with solid centers can be produced which closely
• OMPI approach the .795 maximum limit.
• this end is achieved by forming a center which exceeds the .795 limit and thereafter placing a cover on said center to decrease the coefficient of restitu- tion to .795.-
• the cellular covers of the subject invention are formed by the in situ blowing of the polymeric material during the process whereby the cover is molded on to the core.
• blowing agents may be utilized to effect the foaming of the polymeric material.
• suitable organic blowing agents are as follows: azobisformamide; azobisisobu- tyronitrile; diazoaminobenzene; N, N-dimethyl-N, N-dinitroso terephthalamide; N, N-dinitrosopentamethylene-tetramine; ben- zenesulfonyl-h drazide; benzene-1, 3-disulfonyl hydrazide; diphenylsulfon-3-3, disulfonyl hydrazide; 4, 4'-oxybis benzene -u-
• sulfonyl hydrazide p-toluene sulfonyl semicarbazide; barium azodicarboxylate; butylamin ⁇ nitrile; nitroureas; trihydrazi- no triazine; phenylmethyl-urathane p-sulfonhydrazide; and inorganic blowing agents such as ammonium bicarbonate and sodium bicarbonate.
• blowing agents generally function by their thermal decomposition which creates an in situ gas that is absorbed by the melt. When pressure is released the melt expands to form the foam.
• a gas into the melt under pressure such as nitrogen, air, trichloromonofluoromethane, pentane carbon dioxide, etc. The gas is then absorbed and, again upon release of pressure, the melt expands into a foam.
• the preferred embodiment of this invention utilizes a nitrogen generating blowing agent which is susceptible to thermal decomposition.
• blowing agent utilized in accordance with this invention will vary with the physical and chemical properties of the blowing agent so utilized and the desired apparent density of the resulting golf ball cover.
• from .1 to .5 percent of Ficel EPA is utilized based on the weight of the thermoplastic resin.
• Fical EPA is a trademark used in conjunction with a blowing agent which is essentially azodicarbonamide.
• Ficel EPA is available from Sobin Chemi ⁇ cals, Inc., Sobin Park, Boston, Massachusetts 02201.
• the apparent density of the cellular golf ball cover in accordance with this invention can also be varied by the injection techniques.
• the injection techniques in question
• OM are well understood by one skilled in the art and include such variables as the ram forward time, injecion speed, shot size, gate size, mold venting, injection pressure, holding pressure, etc. It is also well known, that, depending upon the nature of the blowing agent utilized, one can produce a unicellular foam structure or an interconnecting cell structure for the golf ball covers of this invention. In accordance with the pre ⁇ ferred aspect of this invention the golf ball core incorpo- rates a unicellular foam structure.
• the golf ball cover of the subject invention can be applied to a suitable center by a plurality of means.
• the golf ball cover is applied to the core by injec- tion molding.
• a master batch of formulated plastic molding powder is prepared. This master batch is dry blended and includes one or more polymer materials, coloring agents, antioxidants, blowing agents, etc. Naturally, the blowing agent is blended into the polymeric material at a temperature below the decomposi ⁇ tion temperature of said blowing agent. This master batch may then be pelletized. A golf ball center is then posi ⁇ tioned in a mold.
• the above mentioned master batch pellets are then fed into the injection molding machine and the resulting melt is injected into the mold in such a manner that the polymer material foams and flows around and adheres to the core. During this molding process the dimples are formed on the cover. The resulting golf ball is then allowed to cool whereupon an essentially finished golf ball is removed.
• Another significant aspect of the subject invention is that by the use of a cellular cover stock material the net cost of the golf ball cover is decreased.
• High quality poly ⁇ meric materials which are suitable for use as golf ball cover stock material are relatively expensive.
• the cost of the..above described Surlyn resins including in-house processing, before injection molding onto a golf ball core is at least eighty cents ($.80) per pound.
• the utilization of the golf ball cover stock mate ⁇ rial is maximized; that is, more golf ball covers are pro ⁇ quizd per pound of material.
• the resulting composite golf ball cover of the subject invention is likewise advantageous in that the apparent spe ⁇ cific gravity of the cover stock is less than the specific gravity of the balls which are covered with non-cellular materials.
• the apparent specific gravity of the composite cover stock including the non-cellular skins as described above can be from about .65 to about 1.50 in accordance with the broad embodiment of this invention. A preferred range for this apparent specific gravity is from about .65 to about 1.25 with the most preferred apparent specific gravity being from about .75 to about .80.
• these specific gravities must be com ⁇ pared to the specific gravity of the non-cellular material.
• the cellular structure of the subject golf ball cover As a point of reference, it should be noted that the Surlyn resins as used on the prior art golf balls have a specific gravity of .940 to .965. The physical properties and flight characteristics of a golf ball are affected to some degree by the weight dis ⁇ tribution in the resulting finished golf ball. In some instances it is desirable to concentrate the weight as near as possible to the center of gravity of the ball. Consid- ering this fact, advantages in ball design are automatically produced by the subject invention in that a greater per ⁇ centage of the overall weight is concentrated in the center of the ball as compared to a conventional ball with a non- cellular cover.
• this invention is very advantageous because the resulting golf ball has different high speed and low speed impact properties, when compared to a similar ball with a non-cellular cover.
• the cover deforms to such a degree that the club face comes into substantially more contact area with the cover as compared to a ball having a non-cellular cover.
• greater control can be imparted to the ball to allow purposeful manipulation of the ball in play, for example, back spin, drawing, fading.
• the energy required for high speed deformation of the cover is less than neces ⁇ sary with conventional covers. This allows more energy at impact to be " imparted directly into the inner core material where it can enhance the flight of the golf ball.
• this same cellular covered ball has differ ⁇ ent low speed impact properties, which are useful in putting.
• the cellular covered ball required a greater impact force than a conventional ball for the same distance of travel since the cellular cover at low speed impacts creates a deadening effect which is similar to Balata covered balls. It is well known that in putting, margins of error can be greatly reduced when more force is required to move a ball a certain distance on the putting range.
• the cover of this ball is made in accordance with the teachings of ⁇ . S. Patent 3,819,768 issued June 25, 1974.
• Imprint, made by ball B, of Figure 7 was made by a ball which was nearly identical in all respects to the ball used to make imprint C except that the cover stock was cellu- lar using .3 percent of Ficel EPA blowing agent.
• the result ⁇ ing golf ball was similar to the ball described in Example 1 and illustrated in Figures 2 and 4. It can be readily seen that imprint D is larger than imprint C. Imprint C measures 1.020 inches while imprint D measures 1.068 inches.
• the surface distortion of ball B with the steel plate was sig- nificantly greater than the surface distortion of ball A.
• Figure 9 is concerned with the low speed impact proper- ties of a golf ball of this invention.
• balls “A” and “B” as described above in connection with Figure 7 were utilized. These balls were dropped from 100" onto a steel plate.
• Ball “A” formed imprint “G” which had a diameter of .416”.
• Ball “B” formed imprint “H” which had a diameter of .422". Again from the differences in these diameters, it can be seen that ball “B” as per imprint “H” tended to wet out significantly more than ball “A” as per imprint "G”.
• im ⁇ prints "G” and "H” relative to this test it should be noted that in this test ball “A” rebounded to a height of 76" and ball “B” rebounded to a height of 73". This difference in
• Table I below represents data from driving tests as were carried out on the ball of this invention in comparison with standard commercially available balls.
• ball “C” was a standard commercially available two piece ball as sold by the applicant under the trademark “Top Flite”.
• Ball “B” was a ball made in accordance with this invention and generally in accordance with Example I herein below. Ball “C” had a coefficient of resitution of 795. Ball “B” had a coefficient of restitution of 782.
• ball "B” the ball of this invention, had a carry advantage over ball “C” at 145 feet per second. At 160 feet per second ball “C” had a slight carry advantage over ball “B”.
• the carry advantage of ball “B” at 145 feet per second is thought to be particularly significant con ⁇ sidering the additional above enumerated advantageous prop ⁇ erties of the ball of this invention as are reflected in ball "B”.
• club speed of 145 feet per second is high consider ⁇ ing the ability of an ordinary golfer to strike a golf ball. It is felt that a club speed of 145 feet per second would represent the upper spectrum of golfers, such as a 4 or 5 handicap golfer. The test at 160 feet per second, while interesting from a comparative point of view, is not felt to be meaningful relative to the abilities of the average golfer as very few golfers are able to achieve a club speed of 160 feet per second.
• wets out is utilized in describing the deformation of golf balls when they come in contact with golf clubs.
• the term is meant to define the degree to which the spherical golf ball surface deforms to mate up with the plainer non-deformable golf club face.
• the centers in question consist essentially of highly cross linked polybutadiene rubber wherein the principle cross linking agents are peroxides and heavy metal organic salts.
• a wound Center D when a wound Center D is utilized, said center has a diameter of 1.560 + .010", a compression
• OMPI OMPI . WIPO of 90 + 10 PGA, and a coefficient of restitution of .825 + .015.
• said wound center is manufactured by winding in a conventional manner onto a highly resilient polybuta ⁇ diene solid " center having a diameter of 1.125" rubber thread having a high content of polyisoprene, to the above described compression and size dimensions.
• the covers were applied to the respective centers by injection molding techniques wherein the center is pre-positioned in a mold and the cover stock material injected into said mold in such a manner that it flows around the pre-positioned center.
• the center and the mold temperature were approximately 70°F.
• cycle time of said injection molding pro ⁇ cess is such that the material is given ample time to freeze around the pre-positioned center.
• these cycle times are on the order of 30 to 50 seconds depending on mold cooling rates.
• the cycle time varies with the nature of the polymer material being used as cellular cover stock material and in particular its melt temperature.
• barrel test durability data is specified, the 12 balls were fired from a pneumatic cannon for 100 blows at 135 f.p.s ' . at room temperature into an octagonal shaped steel container, 15 inches across first striking a metal plate with corrugations simulating the corrugations on an iron head, then rebounding off of the remaining sides.
• the golf balls were checked for cold cracking durability, 12 balls were fired five times out of the pneu ⁇ matic cannon of the coefficient of restitution machine as described below.
• the muzzle velocity of the balls in ques ⁇ tion was 165 feet per second.
• the balls were fired against a steel plate which was positioned at right angles to the axis of ball flight.
• the steel plate was positioned 10 feet from the muzzle of said cannon. Prior to firing, the balls were conditioned at 0 degrees Fahrenheit for 16 hours.
• guillotine test data was specified, said tests were conducted by placing the ball into a retaining cup holding the lower third of the ball in a fixed position, a free falling weight of 1360 grams having a blunt edged blade similar to the leading edge of an iron club was allowed to fall from a height of 36 inches.
• the coefficient of restitution data as specified below was arrived at by firing 12 balls from a pneumatic cannon at muzzle velocity of 125 f.p.s. against a steel plate which is positioned 10 feet from the muzzle of said cannon, and measuring both the initial velocity and return velocity of said rebounding ball. The ratio of said return
• OMP /., IP velocity to said initial velocity is the specified coeffi ⁇ cient of restitution. The results are reported as the average of the balls so tested.
• low speed rebound data is specified, this data was arrived " at by dropping 12 balls in question from a height of 100" onto a steel plate and measuring the rebound height of the dropped golf ball. The average test results are reported.
• test results of the balls in question are to be compared with a standard Surlyn covered golf ball having a solid center as sold by the applicant under the Trademark TOP-FLITE.
• the ball in question has a PGA compression of 100, a coefficient of restitution of .90, a low speed rebound of 74 inches.
• 12 out of 12 balls passed the cold cracking and durability test, 12 out of 12 balls passed the guillotine test and 12 out of 12 balls passed the barrel test.
• blowing agent 4 parts Surlyn A1557 to 1 part Unitane 0110. Unless otherwise specified, the blowing agent was added via Masterbatch "B" which had the following composition: 4 parts EVA to 1 part Ficel EPA.
• the PGA of the resulting golf ball was 95.
• a barrel test resulted in 12 out of 12 balls passing.
• the cold cracking test resulted in 6 out of 6 balls passing.
• the guillotine test resulted in 12 out of 12 balls passing.
• the coefficient of restitution of the ball was .780. In the low speed rebound test, the ball bounced 72 inches.
• EXAMPLE 2 In this example, center B was utilized. A cover stock was formed in accordance with Table 3 below.
• the compression of the resulting golf ball was 90.
• a barrel test resulted in 12 out of 12 balls passing.
• the cold cracking test resulted in 6 out of 6 balls passing.
• the compression of the resulting golf ball was 110.
• a barrel test resulted in 12 out of 12 balls passing.
• the cold cracking test resulted in 6 out of 6 balls passing.
• the guillotine test resulted in 12 out of 12 balls passing.
• the coefficient of restitution of the ball was .785. In the low speed rebound test, the ball bounced 70 inches.
• center D was utilized, cover stock was formed in accordance with Table 5 below.
• Example 4 was repeated except that a center having the following physical properties was utilized.
• the center had a diameter of 1.550 inches, a coefficient of restitution of
• a cover stock was formed in accordance with Example 4.
• the compression of the resulting golf ball was 93.
• a barrel test resulted in 12 balls no failures.
• the cold cracking test resulted in 12 balls no failures.
• the guil ⁇ lotine test resulted in 12 balls, slight dent in the cover.
• the coefficient of restitution of the ball was 781. In the low speed rebound test, the ball bounced 73 inches.
• Example 4 was repeated except that a center having the following physical properties was utilized.
• the center had a diameter of 1.540 inches, a coefficient of restitution of .800, a weight of 136.7 grams and a PGA compression of 83.
• a cover stock was formed in accordance with Example 4. Because the center was larger in diameter, the cover was naturally thinner. The compression of the resulting golf ball was 97.
• a barrel test resulted in 12 balls no failures.
• the cold cracking test resulted in 12 balls no failures.
• the guillotine -test resulted in 12 balls, slight dent in the cover.
• the " coefficient of restitution of the ball was 775. In the low speed rebound test, the ball bounced 73 inches.
• Example 4 was repeated except that a center having the following physical properties was utilized.
• the center had a diameter of 1.530 inches, a coefficient of restitution of .802, a weight of 136.1 grams and a PGA compression of 84.
• a cover stock was formed in accordance with Example 4. Because the center was larger in diameter, the cover was naturally thinner. The compression of the resulting golf ball was 99.
• a barrel test resulted in 12 balls no failures.
• the cold cracking test resulted in 12 balls no failures.
• the guil ⁇ lotine test resulted in 12 balls, slight dent in the cover.
• the coefficient of restitution of the ball was 772. In the low speed rebound test, the ball bounced 71 inches.

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• 1980
  • 1980-01-15 NZ NZ19261780A patent/NZ192617A/xx unknown
  • 1980-01-18 AU AU54722/80A patent/AU531049B2/en not_active Ceased
  • 1980-01-21 JP JP55500451A patent/JPS6347473B2/ja not_active Expired
  • 1980-01-21 WO PCT/US1980/000107 patent/WO1980001541A1/en unknown
  • 1980-01-21 GB GB8016899A patent/GB2048692B/en not_active Expired
  • 1980-01-28 CA CA000344483A patent/CA1142195A/en not_active Expired
• 1988
  • 1988-05-13 JP JP63115018A patent/JPH01212577A/ja active Pending

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