This application is also a continuation-in-part of application No. 09/376,289, filed on August 18,1999, which is a continuation of application No. 09/096,327, filed on June 12, 1998, now U. S. Patent No. 6,012,991, issued on January 11,2000, the disclosures of which are hereby incorporated by reference thereto in their entireties and the priorities of which are claimed under 35 USC 120.

This application claims priority under 35 USC 119 (e) of U. S. provisional application No. 60/120,590, filed on February 18,1999, and of U. S. provisional application No.

60/070,497, filed on January 5,1998, the disclosures of which are hereby incorporated by reference thereto in their entireties.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to golf balls and, more particularly, to multiple-layer golf balls, including at least a core, an intermediate layer, and a cover.

Further, the present invention relates to a multiple layer golf ball possessing certain physical properties that result in improved ball performance, including enhanced distance, i. e., initial velocity, as well as enhanced spin and playability characteristics.

2. Description of Background and Relevant Information In golf ball design, manufacturers typically have been limited to developing golf balls which are generally categorized as either"distance"balls, characterized by a low spin rate when struck by a driver or other longer, low-lofted club, or"control"balls, characterized by a high spin rate when struck by a short iron, wedge, or other shorter, high-lofted club. For over 40 years, ionomer resins, such as Surlyn (sold by E. I. DuPont de Nemours & Company), and balata materials have been used for manufacturing balls for the aforementioned two golf ball categories, respectively, and no significantly different new materials have been introduced to create a new performance category. Urethane or elastomers have been introduced in the 1980's and 1990's and they have improved golf ball durability, but they have not solved the"distance or control"dichotomy, i. e., whereby a ball has either a low spin rate for maximizing distance, or a high spin rate for maximizing control. Soft Surlyns, balatas, and urethanes are well known in the industry for providing a soft feel and a high spin rate, but they are also known to be "dead", non-resilient materials, thereby not providing significant distance.

A primary golf ball design feature in developing a distance ball is a low driver spin rate.

Low driver spin rates maximize the flight of the ball, with respect to carry and with respect to roll distances. Low spin rates on the driver also reduce the hook or slice spin, making it easier for the average player to keep the ball in the fairway.

To develop a distance ball, i. e., one having a low spin rate, a soft, low compression core should be used. Golf ball cores are typically made from polybutadiene rubber, and they are compression molded under high heat and pressure. It is very difficult to make a large, low compression core by compression molding. Therefore, a typical golf ball core is made low in compression, but also small in size, and the ball is then given a relatively thick cover. As mentioned above, the speed of a distance ball comes from its thick, hard Surlyn cover, which is resilient, unlike the soft Surlyns"or balatas. The net result is a low compression core, for low driver spin, and a fast resilient cover for speed. Therefore, distance is maximized with spin and speed.

Soft, low compression cores are made relatively small in size, as mentioned above, due to a manufacturing limitation. That is, the larger a low compression core is made, the harder it must be made so that, during molding, the core does not expand and blow apart in the press.

A two-piece core of distance balls known in the art has a diameter of about 1.500-1.510 inches and a PGA compression of about 70-75.

Although there is a major benefit in having low compression, hard fast covers for distance, there is a major limitation in the playability of the resulting ball, i. e., a limitation in the"feel"and short game spin and control of the ball. This is where the soft covers have their major benefit. The soft cover produces increased spin when the ball is struck with an iron, whereas balls having hard, fast covers do not. With a ball having a hard cover is similarly struck with an iron, the golfer tends to get"fliers,"as the ball slides up the face of the club, rather than rolling along the face as with the soft covers. Also, the low compression core of the distance ball gives a lower spin rate. This is true for short game spin and, therefore, it is difficult to make a distance ball spin, because of the core and cover that is used for a distance ball.

Wound balls, which typically include a solid or liquid core around which is wound a tensioned elastic thread, covered with an outer layer of either an ionomer resin or balata or an elastomer blend, e. g., have a softer feel at impact and they have a relatively high spin rate. The compression of a wound core is about 90-100. Although distance is sacrificed somewhat, with respect to the aforementioned two-piece balls, wound balls thus provide an improved playability, particularly for experienced players.

With wound balls, the thread is stretched to over 700% of its initial length and, subsequently it creates a very lively, fast, high compression core. A high compression core tends to produce high spin, for drivers and long irons, as well as for short irons. The high tension elastic thread also creates very high short game spin because, when the cover is stuck with an iron, the cover begins to stretch and roll on the face. The thread layer below the cover remains stationary, then is pulled in rotation with the cover. Therefore, the thread stretches and snaps into rotation with the cover.

The aforementioned relationship between compression and spin rate holds true for all ball types, i. e., low compression results in low spin and high compression results in high spin, if other ball characteristics remain constant. With conventional technologies and materials, it is difficult to produce a ball having favorable characteristics for both distance, which typifies

a ball having a low compression core, and playability, which typifies a ball having a high compression core.

United Kingdom Patent Application No. 2,278,609 discloses a multi-layer golf ball which is intended to offer certain advantages of previously known balls employing ionomeric resins, these advantages including improved distance, without sacrificing other advantages of wound or multi-layer balls, such as playability. To that end, U. K. Patent Application No.

2,278,609 discloses a ball having an inner cover layer employing a high acid ionomer or ionomer blend and an outer layer employing a soft, very low modulus ionomer/ionomer blend, or a non-ionomeric thermoplastic elastomer.

On the other hand, commonly owned U. S. Patent No. 5,253,871 discloses a multi-layer golf ball intended to have a considerable initial speed, close to that of the faster balls, such as certain two-piece balls, for favorable performance for drives and shots with the long woods, while also having a good feel, enabling good control or playability during short iron play, such as that for the wound balls. To this end, U. S. Patent No. 5,253,871 discloses a ball having an elastomeric core, a thermoplastic cover, and an intermediate thermoplastic layer composed of at least 10% by weight of an amide block copolyether. As mentioned in U. S. Patent No.

5,253,871, the remarkable property of amide block copolyether is that, in contrast with ionomeric resins, the lower the hardness and modulus, the higher becomes the impact resilience.

Like the ionomer resins, the amide block copolyethers are available in a wide range of hardness and flex modulii. U. S. Patent No. 5,253,871 also discloses the optional addition of an ionomer to the ether block copolymer composition so as to limit the deformation of the ball at impact, while maintaining the hardness of the composition.

The intermediate layer, or mantle, of the ball of U. S. Patent No. 5,253,871 is protected from cutting and peeling by the cover to provide the ball with a good durability. A relatively wide choice of materials is disclosed for the cover. Among the preferred materials are cited ionomers, amide block copolymers of the type used for the mantle but with greater hardness, ionomer and amide block copolymer compounds, thermoplastic polyurethanes, as well as combinations of these materials. At the time of U. S. Patent No. 5,253,871, the high acid ionomers were not publicly known.

Although golf balls employing various constructions and compositions are presently known, the initial speed and, therefore, the distance achieved with such golf balls tends to be limited if the spin rate and, thereby, the playability of such balls is not to be negatively affected.

Similarly, spin rate and playability characteristics of golf balls tend to be limited if initial speed and distance are not to be negatively affected by other constructions and compositions. That is, golf balls according to the prior art are known to have either low driver spin rates for distance, but also low short game spin rates, or high short game spin rates for control, but also high driver spin rates. The field of golf ball design still endeavors to produce a golf ball that is characterized by a low driver spin rate, for distance, coupled with a high short game spin rate, for control.

SUMMARY OF THE INVENTION An object of the present invention is to provide a golf ball that employs a structure and composition which at least substantially maintains the spin rate and playability characteristics of known golf balls, including those manufactured according to the aforementioned commonly owned patent and applications, while improving upon initial speed and distance.

Another object of the present invention is to provide a golf ball that employs a structure and composition which at least substantially maintains initial speed and distance of known golf balls, while improving upon spin rate and playability.

More specifically, it is an object of the invention to provide a golf ball that is characterized by a low driver spin rate, for distance, coupled with a high short game spin rate, for control.

To this end, the golf ball according to the present invention is multi-layered, whereby the core, and the outer intermediate layers have particular physical properties for achieving the aforementioned objects.

More specifically, the intermediate layer includes a thermoplastic copolymer surrounding the core, resulting in an effective core that is relatively large, yet one which is also relatively soft and has a low compression. For example, according to a particular embodiment of the invention, an inner core having a diameter of about 1.480 inches is covered with a very soft,

resilient layer of a thermoplastic copolymer, resulting in an effective core having a relatively large diameter of about 1.580 inches and a relatively low compression, about 65-70 PGA.

Because the effective core, comprised of the aforementioned resilient layer molded to the inner core, retains a low compression, the resulting ball tends to produce a low spin, to create a distance golf ball at driver impacts. Furthermore, because of the particular composition of the thermoplastic intermediate layer, which possesses the physical properties of being very soft and very resilient, the ball tends to produce a unexpectedly high spin rate with short iron impacts.

More particularly, the intermediate layer according to the invention is preferably made of a particular combination of relatively flexible thermoplastic polymer and a hardness- enhancing material, such as a relatively rigid ionomer or ionomer blend, which has been found by experimentation to produce superior results regarding both distance and playability.

A further object of the present invention is to improve upon the performance of the golf ball construction disclosed in the above-mentioned commonly owned U. S. Patent No.

5,253,871, particularly with regard to the use of a particular composition of the core and mantle, as well as with regard to the use of a particular composition of a cover layer, including cover compositions disclosed in the aforementioned application No. 09/136,845 and particular variations thereof, which have been found by experimentation to provide particularly favorable results according to meeting the objective of both distance and control.

As mentioned above, at the time of U. S. Patent No. 5,253,871, the high acid ionomers were not publicly known. However, parent application No. 09/136,845, the disclosure of which is incorporated by reference herein in its entirety, discloses a new composition for a cover that includes a soft amide block copolymer and a harder ionomer, such as a high acid ionomer. The cover composition was found to contribute to the achievement of high values of spin rate for a better control, to improve the feel of the ball and, further, the cover composition was found to contribute to the achievement of an increase in the initial speed and distance of the ball. Still further, in that application, an agent for the compatibilization of the polyamide elastomer and the ionomer in the composition is disclosed for reducing the incidence of cryogenic fractures and delamination at the interface between the ionomer and the polyamide elastomer.

Particularly because of the availability of high-acid ionomers, it has now been found that significantly more thermoplastic elastomer can be employed in the mantle layer, with the achievement of at least comparable results, than the amounts contemplated in the golf balls of U. S. Patent No. 5,253,871. In U. S. Patent No. 5,253,871, it is disclosed that as little as 10 weight percent of a thermoplastic elastomer, such as an ether block copolymer is to be employed in the mantle layer, with a remainder including, e. g., one or more ionomers for enhancing the hardness of the mantle. The present invention contemplates a range of about 50 % to 95 % by weight and, more preferably, at least about 69 % by weight, preferably 69 % to 71 % by weight, of a soft, flexible resin, such as a thermoplastic elastomer and a hardness-enhancing material, including at least one ionomer, such as a Surlyn, or combination of Surlyns. Although proportions of thermoplastic elastomer greater than 10% were disclosed in variations in U. S.

Patent No. 5,253,871, the unavailability of the high-acid ionomers resulted in somewhat lesser ball performance for those variations than for balls made according to the present invention.

In parent U. S. Patent No. 6,012,991, the subject matter of which is incorporated by reference thereto in its entirety, a multiple-layer golf ball is disclosed that utilizes, inter alia, an intermediate layer that includes a soft, flexible resin reinforced with at least one hardness- enhancing material. The soft, flexible resin of the intermediate layer according to the invention, and as disclosed in U. S. Patent No. 6,012,991 and according to preferred embodiments of this invention, encompass an elastomer, such as an amide block polyether. Pebax 2533 and Pebax" 3533 are examples of elastomers which are found suitable for the invention, as disclosed in the aforementioned parent applications. Pebax has the remarkable and probably unique property of increasing in resilience while decreasing in hardness. Preferably, according to U. S. Patent No. 6,012,991, the hardness-enhancing material can include a quantity of non-continuous fiber elements in the intermediate layer. A"control"ball disclosed in U. S. Patent No. 6,012,991 was otherwise constructed according to the invention, but the fibrous hardness-enhancing material was replaced with a high-acid ionomer blend. Favorable performance is achieved regarding a relatively low driver spin rate and a relatively high short game spin rate.

A further contributor to achieving the performance results of the invention, as disclosed in U. S. Patent No. 6,012,991, in contrast to balls according to the prior art, is a relatively large diameter core-intermediate layer, which also includes a relatively low compression.

In summary, the present invention is directed to achieving a favorably high spin rate for the short game, as well as a favorably low spin rate for the long game. This is achieved according to the invention by employing a core-intermediate layer combination having a relatively low compression and a relatively large diameter. Further, the invention includes a particular range of intermediate layer/core combinations with a particular range of covers to meet the objects of the invention.

The following are exemplary physical characteristics of a ball constructed according to the invention: the core diameter is preferably within the range of about 1.470-1.490 inches and a PGA compression in the range of about 60-85, more preferably about 70-75; the mantle has a diameter in the range of about 1.570-1.600 inches, preferably about 1.570-1.590 inches, and more preferably about 1.577-1.583 inches; the core and mantle have a combined PGA compression in the range of about 60- 859 more preferably about 65-75; the finished ball has a PGA compression in the range of about 70-90, more preferably about 75-85; the cover has a shore D hardness in the range of about 46-69 and, more preferably, one of the following: approximately 48-52, with a target of 51; approximately 54-58, with a target of 56; approximately 60-64, with a target of 62; the cover has a diameter in the range of about 1.680-1.690 inches, more preferably about 1.682-1.687 inches; the complete ball has a coefficient of restitution (COR), at 125 feet per second inbound, of greater than 0.785, more preferably about 0.795-0.810; and the complete ball has a weight in the range of about 1.580-1.620 ounces, more preferably about 1.595-1.610 ounces.

BRIEF DESCRIPTION OF THE DRAWING Other advantages and characteristics of the invention will be better understood upon reading the description that follows and with reference to the annexed single figure of drawing

illustrating, by way of example, a golf ball according to the invention, including, in the illustrated example, a single intermediate layer surrounding a core and lying beneath a cover.

DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to golf balls, including their structures and compositions and, further, including their physical performance results. More particularly, the present invention relates to a multi-layer golf ball, an exemplary embodiment of which is shown schematically in the drawing figure. The golf ball includes a core 1, an outer cover 3, and an intermediate layer 2. The intermediate layer or mantle 2 is shown to be immediately beneath the outer layer or cover 3. The invention encompasses, however, an intermediate layer that can be one of a plurality of layers beneath a cover layer. Also, the relative sizes of the diameters and thicknesses of the core, intermediate layer, and cover shown in the figure are intended to be exemplary and non-limiting.

The core 1 of the golf ball according to the invention can take any of several known forms. As an example, not to be taken as limiting, the composition of the core 1 can be made of a polybutadiene elastomer, as described in U. S. Patent Nos. 5,253,871 and 6,012,991, the disclosures of which are incorporated by reference thereto for this purpose.

It is important to the present invention that the core has a relatively large diameter and, importantly, as mentioned elsewhere, that the combination of core-intermediate layer has a relatively large diameter. In this regard, the outer diameter of the core should be in the range of approximately 1.470 inches to approximately 1.490 inches, more preferably approximately 1.477-1.483 inches, and still more preferably about 1.480 inches. As an example, the density of the core can be comprised between approximately 1 and 1.3 g/cm3, more preferably approximately 1.176-1.184 g/cm3, and still more preferably about 1.180 g/cm3.

The core 1 is preferably made of a thermoplastic or thermohardenable or vulcanizable elastomer. According to one preferred embodiment, the core is made of a crosslinked diene elastomer of the polybutadiene cis-1,4 type containing a reaction product with zinc oxide and zinc diacrylate. The composition also preferably contains a crosslinking agent such as organic peroxide, for example. Sulfur and/or sulfur derivatives can also be used as cross-linking agents.

In preferred embodiments, the shore C hardness of the core is preferably within the range of approximately 75 and 90, and the PGA compression is within the range of approximately 40 to approximately 90, preferably about 60-85. In specific examples according to the invention, the PGA compression is approximately 63-77, most preferably about 70, or approximately 68-82, most preferably about 75.

In certain embodiments, the mantle 2 has a thickness of approximately 0.013 inches to approximately 0.070 inches. In more preferred embodiments, the mantle 2 has a thickness of approximately 0.04-0.06 inches, and more preferably approximately 0.05 inches. In any event, the resultant diameter of the mantle is preferably in the range of approximately 1.570 inches to approximately 1.600 inches, more preferably approximately 1.570 to approximately 1.590 inches, more preferably approximately 1.577 inches to approximately 1.583 inches and, most preferably about 1.580 inches.

The mantle layer is comprised of a soft, flexible resin, such as a thermoplastic elastomer, preferably having a weight percent within the range of about 50 % to 95 %, more preferably, at least about 69% and, most preferably, about 69 % to 71 %. The remainder of the composition of the mantle includes a hardness-enhancing material, such as at least one ionomer, such as a Surlyn", or a combination of Surlyns".

The combination of the mantle and core according to the invention produce an"effective core"that is relatively large, yet one which is also relatively soft and has a low compression.

For example, according to a particular embodiment of the invention, an inner core having a diameter of about 1.480 inches is covered with a very soft, resilient layer of a thermoplastic blend, resulting in an effective core having a relatively large diameter of about 1.580 inches and a relatively low compression, about 65-70 PGA.

Because the effective core, comprised of the aforementioned resilient layer molded to the inner core, retains a low compression, the resulting ball tends to produce a low spin, to create a distance golf ball at driver impacts. Furthermore, because of the particular composition of the resilient mantle layer, which possesses the physical properties of being very soft and very resilient, the ball tends to produce unexpectedly high spin rates with short iron impacts.

Further, because of the relatively large size of the effective core, i. e., the mantle layer/core combination and, consequently, the relative thinness of the cover layer of the invention, the

ability to achieve high spin rates is enhanced, particularly with regard to known balls which employ thicker hard Surlyn covers.

In this regard, the high loft of the iron blade, particularly that of the shorter irons, stretches the cover of the ball at impact to initiate backspin. The resilient mantle layer of the ball of the invention also stretches and then snaps in the same direction as the cover to produce even more spin. This produces a new level of stopping power, even on firm greens, in contrast to known balls. On the other hand, the low-lofted club face, particularly that of the driver and longer clubs, compresses both the cover and the mantle layer. Unlike other soft materials, that of the mantle layer of the ball of the invention is very resilient, quickly rebounding back to its original shape, transferring maximum energy into the core and exploding off the club face with reduced spin for longer, straighter drives.

The cover can comprise any of those according to one or more of the compositions disclosed in U. S. Patent Application Nos. 08/915,081 and 09/136,845, the disclosures of which are incorporated by reference for the purpose of disclosing such compositions. In addition, it is contemplated that the outer surface of the ball according to the invention has a dimple pattern such as that disclosed in U. S. Patent No. 5,201,522, the disclosure of which is hereby incorporated by reference thereto, although other such dimple patterns are also contemplated.

In the following examples, entitled"Ball 1","Ball 2", and"Ball 3", preferred constructions of balls are identified which have been found to perform advantageously to achieve the objects of the invention. In addition, the invention contemplates balls constructed according to the disclosures of the aforementioned parent application No. 09/136,845 and U. S.

Patent No. 6,012,991.

Ball 1 Description Units Value CORES Core Size in. diameter 1.480 Core Compression PGA units 70 MANTLES Mantle Formation % by weight 70% Pebax 3533 15 % Surlyn 8140 Na 15 % Surlyn 9120 Zn Mantle Size in diameter 1.580 Mantle hardness Shore D 40 COVER Cover Formulation pph 40 pph Pebax 2533 60 pph Surlyn 6120 Mg 5 pph Lotader AX 8900 Finished ball Size (pole) in dia. 1.683 Ball Size (equator) in dia. 1.683 Ball Weight grams 45.54 Cover Hardness Shore D 50 Ball Compression PGA units 75 DIMPLES Dimple Pattern preferably according to U. S. Patent No. 5,201,522 Dimple numbers number 442 Dimple Sizes 1 Performance data Units Result 8-Iron spin rate rpm 8400 Driver spin rate rpm 3200 Ball 2 Description Units Value CORES Core Size in. diameter 1.480 Core Compression PGA units 70 MANTLES Mantle Formation % by weight 70% Pebax 3533 15% Surlyn 8140 Na 15% Surlyn 9120 Zn Mantle Size in diameter 1.580 Mantle hardness Shore D 40 COVER Cover Formulation pph 20 pph Pebax 2533 80 pph Surlyn 6120 Mg 2.5 pph Lotader AX 8900 Finished ball Size (pole) in dia. 1.683 Ball Size (equator) in dia. 1.683 Ball Weight grams 45.54 Cover Hardness Shore D 62 Ball Compression PGA units 83 DIMPLES Dimple Pattern preferably according to U. S. Patent No. 5,201,522 Dimple numbers number 442 Dimple Sizes 1 Performance data Units Result 8-Iron spin rate rpm 8000 Driver spin rate rpm 2950 Ball 3 Description Units Value CORES Core Size in. diameter 1.480 Core Compression units 75 MANTLES Mantle Formation % by weight 70% Pebax 3533 15% Surlyn 8140 Na 15 % Surlyn 9120 Zn Mantle Size in diameter 1.580 Mantle hardness Shore D 40 COVER Cover Formulation pph 30 pph Pebax 2533 70 pph Surlyn 6120 Mg 2.5 pph Lotader AX 8900 Finished ball Size (pole) in dia. 1.683 Ball Size (equator) in dia. 1.683 Ball Weight grams 45.54 Cover Hardness Shore D 50 Ball Compression PGA units 80 DIMPLES Dimple Pattern preferably according to U. S. Patent No. 5,201,522 Dimple numbers number 442 Dimple Sizes 1 Performance data Units Result 8-Iron spin rate rpm 8200 Driver spin rate rpm 3100

In Ball 1, the cover composition is the following: Pebax"2533: 40 parts per hundred Surlyn 6120: 60 parts per hundred Lotader'AX8900: 5 parts per hundred Pebax'2533 identifies an amide block polyether having a hardness of 25 shore D (according to ASTM D-2240), a flexural modulus of 2.1 kpsi (according to ASTM D-790), and a Bayshore resilience of about 62 % (according to ASTM D-2632).

Surlyn 6120 identifies a high acid ionomer resin sold by E. I. DuPont de Nemours & Company, and having the following characteristics and properties: Cation type: Mg Melt flow Index: 1.3 g/10 min (ASTM D-1238) Specific gravity: 0.95 (ASTM D-792) Tensile strength: 5.2 kpsi (ASTM D-638) Yield strength: 2.9 kpsi (ASTM D-638) Elongation: 270 % (ASTM D-638) Hardness: 67 shore D (ASTM D-2240) Flexural Modulus: 75 kpsi (ASTM D-790) Bayshore resilience: 59 % (ASTM D-2632) Lotader AX8900 identifies a terpolymer of ethylene, n-butyl acrylate, and glycidyl methacrylate produced by Elf-Atochem Co.

In Ball 2, the cover composition is the following: Pebax 2533: 20 parts per hundred Surlyn 6120: 80 parts per hundred Lotader AX8900: 2.5 parts per hundred In Ball 3, the cover composition is the following: Pebax 2533: 30 parts per hundred

Surlyn 6120: 70 parts per hundred Lotader'AX8900: 2.5 parts per hundred For each of Ball 1, Ball 2, Ball 3, the composition of the intermediate layer is the following: Pebax'3533: 70 parts per hundred Surlyn 8140: 15 parts per hundred Surlyn1 9120: 15 parts per hundred Pebax 3533 identifies an amide block polyether having a hardness of about 35 shore D (according to ASTM D-2240), a Flexural Modulus of 2.8 kpsi (according to ASTM D-790), and a Bayshore resilience of about 59% (according to ASTM D-2632).

Surlyn"8140 identifies a high acid ionomer resin sold by E. I. DuPont de Nemours & Company, and having the following characteristics and properties: Cation type: Na Melt flow Index: 2.6 g/10 min (ASTM D-1238) Specific gravity: 0.95 (ASTM D-792) Tensile strength: 34.5 MPa (ASTM D-638) Yield strength: 19.3 MPa (ASTM D-638) Elongation: 340 % (ASTM D-638) Hardness: 70 shore D (ASTM D-2240) Flexural Modulus: 545 MPa (ASTM D-790) Bayshore resilience: 62 % (ASTM D-2632) Surlyn 9120 identifies a high acid ionomer resin sold by E. I. DuPont de Nemours & Company, and having the following characteristics and properties: Cation type: Zn Melt flow Index: 1.3 g/10 min (ASTM D-1238) Specific gravity: 0.97 (ASTM D-792) Tensile strength: 3.8 kpsi (ASTM D-638)

Yield strength: 2.4 kpsi (ASTM D-638) Elongation: 280 % (ASTM D-638) Hardness: 69 shore D (ASTM D-2240) Flexural Modulus: 64 kpsi (ASTM D-790) Bayshore resilience: 64 % (ASTM D-2632) The cores for Ball 1, Ball 2, and Ball 3 are essentially the same, being made of a <BR> <BR> <BR> polybutadiene rubber. The PGA compression of the core of Ball 1, however, is about 70, +/- 7, whereas that of Balls 2 and 3 is about 75, +/-7.

It is also noted that the composition of Ball 1 is similar to the control ball disclosed in Table 2 of parent U. S. Patent No. 6,012,991.

The data appearing in the tables of Ball 1, Ball 2, and Ball 3 represent trials conducted on a minimum of 12 golf balls. The values for the coefficient of restitution were obtained by using an air cannon, according to conventional techniques. The performance data for the balls in the tables, i. e., the driver spin rate and the 8-iron spin rate, was obtained with the use of a Golf Labs, Inc. swing robot, as mentioned in parent application No. 09/136,845, the disclosure of which is incorporated by reference thereto for this purpose. For example, for obtaining the driver spin rate data, the robot was set-up for Pinnacle"Gold", a 9'aérage launch angle, 160 mph ball speed, and a backspin of 3000 rpm, with a 7° titanium driver at a 110 mph head speed. For the obtaining the 8-iron spin rate data, the robot was set-up for Titleist Tour Balata, a 19°-20° launch angle, 110 mph ball speed, and a backspin of 9000 rpm, with an 8- iron at a 90 mph head speed.

It can be seen that all three balls produce superior results. That is, the driver spin rate is relatively low, facilitating distance, and the 8-iron spin rate is relatively high, facilitating control for the short game. Specifically, the spin rate for the driver for the three balls is about 2950 rpm, 3100 rpm, and 3200 rpm for Balls 2,3, and 1, respectively. For the 8-iron, the spin rate for the three balls is about 8000 rpm, 8200 rpm, and 8400 rpm for Balls 2,3, and 1, respectively.

As mentioned above, all three balls have an identical mantle layer composition, including 70 wt% of Pebax, the remainder a blend of high-acid ionomers. Although advantageous results

are found for a wider range, such as 50 wt% to 95 wt%, as mentioned above, it has been found that about 70 wt% of Pebax in the mantle layer enables the ball to achieve 8-iron spin rates in the range of about 7900-8500 rpm, depending upon, e. g., the cover composition selected. The range of about 7900-8500 rpm, in a controlled set-up, is found to be ideal for most players. If the spin rate is significantly higher than this range, the ball tends to"balloon"in the wind and, also, the ball tends to be"sucked"back off the green. On the other hand, if the spin rate is significantly lower than this range, the ball will not"bite"on the green and it will release from the pin. Therefore, with the core compression and covers contemplated by the invention, the aforementioned 70 wt% Pebax in the mantle layer has been found to be optimal.

However, if another Pebax were to be used, the 70 wt% would be changed. For example, Pebax 1205 has a hardness of about 40-45 shore D and, with an equivalent proportion in the mantle layer, the ball would produce less spin. Therefore, if Pebax 1205 were to be used, the proportion in the mantle layer would be changed accordingly to meet the desired performance.

As mentioned above, all three balls have an identical mantle layer composition. The slightly different spin rates are achieved, therefore, as a result of the composition of the cover layer. The cover layer of Ball 2 includes 20 pph (parts per hundred) of Pebax 2533 and 80 pph of the hardness-enhancing agent (Surlyn 6120), resulting in an 8-iron spin rate of about 8000 rpm and a driver spin rate of about 2950 rpm. By somewhat increasing the percentage of Pebax and somewhat decreasing the percentage of Surlyn, the resulting spin rates are caused to increase, yet both still remain advantageous. Specifically, the proportion of Pebax in the cover layer of Ball 3 is increased to 30 pph and the proportion of Surlyn is decreased to 70 pph, resulting in an 8-iron spin rate of about 8200 rpm and a driver spin rate of about 3100 rpm. For the cover layer of Ball 1, the proportion of PebaxX in the cover layer is increased to 40 pph and the proportion of Surlyn"is decreased to 60 pph, resulting in an 8-iron spin rate of about 8400 rpm and a driver spin rate of about 3200 rpm.

The 20,30, and 40 pph of Pebax in the cover layer are designed to give a desired cover hardness for better players, namely, 50-55 shore D hardness for the 40 pph Pebax, to 60-65 pph shore D hardness for the 20 pph Pebax". The 30 pph Pebax composition creates a feel for the player between the other two ball types, and contrasts with most of the balls currently used by better players. As a result of the variation in Pebax in the outer layer, i. e., as a result of

the variation in the hardness of the outer layer, with other components of the multi-layer ball being essentially unchanged, balls of different levels of spin performance and different levels of feel are possible. Some players prefer a softer feel, while some players prefer a harder feel.

Therefore, the blending of the elastomer with the hardness-enhancing material, i. e., the blending of the Pebax and Surlyn in the examples of Ball 1, Ball 2, and Ball 3, enables the player to select a ball having the desired feel, yet a ball having both advantageous distance and short game spin rates. In summary, according to the invention, balls are provided which have a relatively high 8-iron spin rate of equal to or greater than about 7900 rpm, preferably within the range of about 7900-8500 rpm, yet which have a driver spin rate of equal to or less than about 3400 rpm, preferably equal to or less than 3200 rpm, and according to certain preferred embodiments, as low as about 2950 rpm.

As mentioned above, the following are exemplary physical characteristics of a ball constructed according to the invention, including those of Balls 1,2, and 3: the core diameter is preferably within the range of about 1.470-1.490 inches and a PGA compression in the range of about 60-85, more preferably about 70-75; the mantle has a diameter in the range of about 1.570-1.600 inches, more preferably about 1.570-1.590 inches, and more preferably about 1.577-1.583 inches; the core and mantle have a combined PGA compression in the range of about 60- 85, more preferably about 65-75; the finished ball has a PGA compression in the range of about 70-90, more preferably about 75-85; the cover has a shore D hardness in the range of about 46-69 and, more preferably, one of the following: approximately 48-52, with a target of 51; approximately 54-58, with a target of 56; approximately 60-64, with a target of 62; the cover has a diameter in the range of about 1.680-1.690 inches, more preferably about 1.682-1.687 inches; the complete ball has a coefficient of restitution (COR), at 125 feet per second inbound, of greater than 0.785, more preferably about 0.795-0.810; and the complete ball has a weight in the range of about 1.580-1.620 ounces, more preferably about 1.595-1.610 ounces.

As mentioned previously, in parent U. S. Patent No. 6,012,991, the hardness-enhancing material can include a quantity of non-continuous fiber elements in the intermediate layer, mixed with a quantity of elastomer, such as the aforementioned Pebax materials. The fiber elements can be the only hardness-enhancing material, or a quantity of an ionomer, such as one of the Surlyns"can also be added. As with the balls in the three tables, above, the effective core, i. e., the combined core and mantle of the balls according to U. S. Patent No. 6.012,991 is relatively large, relatively soft, and has a relatively low compression. For example, the effective core has a diameter of about 1.580 inches and a PGA compression about 65-70. As mentioned above, because the effective core has a low compression, the resulting ball tends to produce a low spin at driver impacts, thereby enhancing the distance achieved. Furthermore, because of the particular composition of the resilient layer, which possesses the physical properties of being very soft and very resilient, the ball tends to produce a unexpectedly high spin rate with short iron impacts.

As can be seen in the examples of golf balls presented in Tables 1 and 2 of parent U. S.

Patent No. 6,012,991, the driver and 8-iron spin rates are advantageous, although the latter is designed to be somewhat higher than those of Ball 1, Ball 2, and Ball 3, above, i. e., higher than about 8500 rpm, although one example (CF-20, Table 1) is within the range of the Balls 1,2, and 3, i. e., at 8540 rpm. In addition, the driver spin rates are also designed to be somewhat higher than those of Ball 1, Ball 2, and Ball 3, above, i. e., higher than about 3400 rpm, although the aforementioned example (CF-20) is within the range of the Balls 1,2, and 3, i. e., at 3335 rpm. Further, the control ball in Table 2, having 70 wt % Pebax in the mantle layer, is within the range of the Balls 1,2, and 3, above, having an 8-iron spin rate of 8500 rpm and a driver spin rate of 3400 rpm.

Although the preferred embodiments have been described in detail hereinabove, certain modifications may be envisioned by one of ordinary skill in the art, without departing from the scope of the invention, which is encompassed by the claims which follow.