WO1999008756A1 - Compositions pour enveloppes de balles de golf et balles de golf a enveloppes ameliorees - Google Patents

Compositions pour enveloppes de balles de golf et balles de golf a enveloppes ameliorees Download PDF

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Publication number
WO1999008756A1
WO1999008756A1 PCT/US1998/017231 US9817231W WO9908756A1 WO 1999008756 A1 WO1999008756 A1 WO 1999008756A1 US 9817231 W US9817231 W US 9817231W WO 9908756 A1 WO9908756 A1 WO 9908756A1
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WO
WIPO (PCT)
Prior art keywords
golf ball
ionomer
hardness
elastomer
acid
Prior art date
Application number
PCT/US1998/017231
Other languages
English (en)
Inventor
Hyun Kim
Dean Snell
Philippe Renard
Benoit Vincent
Original Assignee
Adidas-Salomon Usa, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Adidas-Salomon Usa, Inc. filed Critical Adidas-Salomon Usa, Inc.
Priority to AU89158/98A priority Critical patent/AU8915898A/en
Priority to JP2000509491A priority patent/JP2003504089A/ja
Priority to GB0004076A priority patent/GB2343123A/en
Publication of WO1999008756A1 publication Critical patent/WO1999008756A1/fr

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L77/00—Compositions of polyamides obtained by reactions forming a carboxylic amide link in the main chain; Compositions of derivatives of such polymers
    • 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
    • A63B37/0031—Hardness
    • 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
    • A63B37/0037—Flexural modulus; Bending stiffness
    • 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
    • A63B37/0038—Intermediate layers, e.g. inner cover, outer core, mantle
    • A63B37/0039—Intermediate layers, e.g. inner cover, outer core, mantle characterised by the 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
    • A63B37/005—Cores
    • A63B37/0051—Materials other than polybutadienes; Constructional details
    • 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
    • A63B37/006—Physical properties
    • A63B37/0064—Diameter
    • 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
    • A63B37/006—Physical properties
    • A63B37/0065—Deflection or compression
    • 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
    • A63B37/007—Characteristics of the ball as a whole
    • A63B37/0072—Characteristics of the ball as a whole with a specified number of layers
    • A63B37/0074—Two piece balls, i.e. cover and core
    • 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
    • A63B37/007—Characteristics of the ball as a whole
    • A63B37/0072—Characteristics of the ball as a whole with a specified number of layers
    • A63B37/0075—Three piece balls, i.e. cover, intermediate layer and core
    • 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
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L77/00—Compositions of polyamides obtained by reactions forming a carboxylic amide link in the main chain; Compositions of derivatives of such polymers
    • C08L77/06—Polyamides derived from polyamines and polycarboxylic acids
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L77/00—Compositions of polyamides obtained by reactions forming a carboxylic amide link in the main chain; Compositions of derivatives of such polymers
    • C08L77/12—Polyester-amides
    • 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
    • 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

Definitions

  • the present invention relates generally to golf balls and, more particularly, to golf balls having an improved cover layer.
  • the present application also relates to thermoplastic compositions suitable for golf ball covers.
  • the invention further relates to two piece golf balls, to wound golf balls, and to multi-piece solid golf balls as well.
  • the invention relates to compositions suitable for two-piece golf balls, wound golf balls, and multi-piece solid golf balls, as well.
  • the modern golf ball generally comprises a cover including layers made of ionomeric resins, in a pure form or in a blend.
  • Ionomeric resins are polymers containing ionic groups or ionic salts in a polymer structure. More particularly, the ionomers are intended to be the ionomeric resins obtained by providing a cross-metallic bond to polymers of monoolefms with at least one member selected from the group consisting of unsaturated mono- or di-carboxylic acids having at least 3 to 12 atoms, and esters thereof.
  • the ionomeric resins are distinguished by the type of metal ion, the acid content, and the degree of neutralization. There is currently a wide choice of commercial ionomers available both from E. I.
  • DuPont de Nemours & Company Wilmington, Delaware, under the trademark name “Surlyn”, and from Exxon, under the trademark name “Iotek”, with a wide range of properties (such as flexural modulus and hardness, for example) which vary according to the type and amount of metal cations, molecular weight, composition of the base resin and additive ingredients, such as reinforcement agents.
  • the high acid-ionomers which have been recently developed, have a very high flexural modulus due to the high acid content and they provide a high level of resilience.
  • the resilience imparts to the ball an increased initial velocity. Therefore, the ball travels a greater distance than a ball having a lower initial velocity.
  • the main disadvantage of these covers made of pure high acid ionomers is their extremely great hardness (68 shore D and higher). Therefore, balls made of high acid covers have a very "hard" feel and a low spin rate, which renders it difficult to control the distance of the ball with short irons.
  • High acid ionomer covers also have a tendency to crack after multiple hits with a driver or similar long club.
  • UK-A-2,278,609 proposes to use a high acid ionomer as an inner cover layer and a softer polymeric material of low flex modulus ionomer resin and non-ionomeric thermoplastic elastomer for the outer cover layer to compensate for the hard feel of the high acid ionomer resin.
  • VLMI Very Low Modulus Ionomers
  • VLMI cover also has a very poor cut and shear durability. In consequence, it has been common to blend the VLMI with other higher flex modulus ionomers to produce a desired range of hardness for the cover. However, the gain in performance, in particular in distance, has not been proven to be particularly significant.
  • VLMI include Surlyn 8120 (sodium cation), 8320 (sodium cation), and 9320 (zinc cation).
  • Surlyn 8320 has the lowest value of Flexural Modulus (2.8 kpsi or 19.3 MPa).
  • U.S. Patent No. 5,253,871 to Viollaz is directed to a multi-piece golf ball having an intermediate mantle between the cover and the core which comprises at least 10% by weight of amide block copolyether.
  • this material is protected from cutting and peeling by the cover and, therefore, the ball has a good durability.
  • the remarkable property of this material is that, in contrast with the ionomeric resins, the lower the hardness and modulus, the higher becomes the impact resilience.
  • the amide block copolyethers are available in a wide range of hardness and flex modulii.
  • U.S. Patent No. 5,253,871 also proposes a relatively wide choice of materials for the cover.
  • 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.
  • the high acid ionomers were unknown to the public.
  • the present invention pertains to all types of golf balls, including two-piece balls, three-piece solid balls, and wound balls.
  • a cover made of such a composition would exhibit a lower shear resistance than a conventional ionomer cover.
  • the results of tests which have been conducted, and are discussed herein have shown that the cover may be easily cut or its surface damaged when the ball is hit with a short iron golf club which transfers a high spin rate to the golf ball.
  • there are durability problems which result in the cracking of the cover after only a few number of shots. Problems of delamination have yet additionally been noticed after injection of the cover around the rest of the inner spherical structure.
  • composition shows cryogenic fractures and delamination at the interface between the ionomer and the polyamide elastomer.
  • a heterogeneous dispersion of the mixed polymers has been also observed.
  • the ionomeric resin comprises long linear polyethylene chains that have little or no polarity except for several carboxylic groups.
  • the polyamide block elastomer comprises numerous polar amide groups which have no chemical affinity with the ethylene chains.
  • thermoplastic compositions comprising: a thermoplastic polymer selected from copolyetheramides and copolyetheresters; an epoxy-containing compound; and an acid- containing ethylene copolymer ionomer.
  • the composition provides improved features of durability which make it suitable for use in a center of a wound golf ball, a core of a two- piece solid golf ball, or a one-piece golf ball for use in driving ranges.
  • This patent further discloses that where the composition has a flex modulus of about 14,000-30,000 psi (ASTM D790. procedure B), preferably without filler, it may also be employed for golf ball cover materials.
  • such a composition has certain disadvantages for use as a golf ball cover and, more particularly, for use as the outermost layer of the cover. Indeed, where the relative proportions of thermoplastic elastomer and ionomer are such that the amount of the thermoplastic elastomer is so much greater than that of the ionomer, the cover is rendered too soft, causing loss of distance and ballooning trajectory due to an abnormally high spin rate. Poor cutting resistance would also be expected even in presence of the epoxy-containing compound.
  • the present invention is directed to a golf ball and, more particularly, to a cover composition for a golf ball that provides for the ball improved spin and feel characteristics, but at the same time, that shows an unattended increase in distance.
  • the invention is directed to a compound for a golf ball cover which comprises:
  • the invention is directed to a cover which includes at least one thermoplastic layer made of the foregoing compound. Yet additionally in this first embodiment, the invention is directed to a golf ball which includes a core and this cover.
  • the invention enables the adjustment of the cover hardness to a determined value in order to control the feel and spin rate of the golf ball as precisely as desired.
  • the invention is directed to maintaining a cover with a high resilience when blending a "fast" material, which is the hard ionomer, with a softer but resilient material to obtain a desired cover hardness, a high spin for both control and distance and a good feel.
  • the soft amide block copolymer has the function of lowering the hardness to the desired value without sacrificing significant loss in resilience. Furthermore, it results surprisingly from the softening of the hard ionomer by the soft amide block copolymer that the spin rate of the ball increases significantly in comparison with a high flex ionomer softened by a VLMI, for example. Therefore, the soft amide block copolymer, which replaces the VLMI in the context particularly of this first embodiment of the present invention, plays a key role in the increase of the spin to the golf ball, and more generally to the performance of the golf ball.
  • the amide block copolymer offers to the cover a tendency (1) to deform elastically under the momentum forces applied by the club face at impact and (2) to release more energy transformed into spin to the ball just after impact.
  • the harder ionomer in the blend gives the properties of high resilience to have a high velocity imparted to the ball.
  • the ionomer also increases high shear resistance which confers more durability of the cover.
  • amide block copolymer is commercially available in a wide range of hardnesses, a cover made purely of this material would not provide sufficient peeling and cut resistance.
  • the cover can comprise a layer having:
  • the cover also experiences a weakness in cut and shear resistance.
  • the invention is directed to a compound for a golf ball cover which comprises:
  • the present invention is also directed to a cover which includes at least one thermoplastic layer made of the foregoing compound. Still further, the invention is directed to a golf ball which includes a core and this cover.
  • the polyamide elastomer is very soft and has a hardness of 35 shore D or less.
  • the polyamide elastomer is a soft amide block copolymer. More preferably, the amide block copolymer is a polyetheresteramide.
  • the high acid ionomer is intended to be an ionomer including at least 16 weight percent, or about 18-19 weight percent, or at least 19 weight percent, of an alpha, beta- unsaturated carboxylic acid. More preferably, the high acid ionomer comprises acid groups partially neutralized by lithium.
  • the high acid ionomer neutralized with lithium is the ionomer which provides the highest impact resilience when tested with respect to other high acid ionomers neutralized with different cations such as zinc, magnesium, sodium, etc.
  • these ionomers preferably include about 18-19 weight percent, or at least 19 weight percent, of an alpha, beta-unsaturated carboxylic acid.
  • the present invention further is directed to a golf ball cover composition that provides exceptional mechanical properties and reasonable softness - i.e., an increase of the tensile and elongation properties - while at the same time providing a high level of cutting resistance and durability, which makes it suitable for directly contacting the club striking face.
  • composition for a golf ball cover which comprises:
  • an elastomer particularly a soft elastomer, comprising at least one member selected from the group consisting of polyamide elastomers and polyester elastomers;
  • a compatibilizer or compatibilizing agent.
  • This agent comprises a copolymer which comprises at least one monomer, with this at least one monomer comprising at least one functional group selected from the group consisting of cyclic functional groups and noncyclic functional groups.
  • the indicated at least one monomer can comprise at least one cyclic functional group and/or at least one noncyclic functional group.
  • the copolymer can comprise one or more monomers comprising at least one cyclic functional group, and also one or more monomers comprising at least one noncyclic functional group.
  • the composition of the invention comprises about 0.3 to 10 wt % of the compatibilizer, with the compatibilizer
  • composition of the invention comprises 10 wt % or less, or less than 10 wt %, of the compatibilizer, with the compatibilizer comprising a copolymer which comprises at least one monomer comprising a noncyclic functional group; and
  • the functional group interacts physically and/or chemically, with one or both of the elastomer and the ionomer, to reduce the interfacial tension, which helps bring about a homogenous mixing of these polymers.
  • the invention is directed to a cover which includes the foregoing composition - particularly, to a cover which includes at least one thermoplastic layer made of the foregoing composition. Yet additionally in this second embodiment, the invention is directed to a golf ball which includes a core and this cover.
  • the indicated golf ball cover composition of this second embodiment is in the form of a discontinuous phase dispersed within a matrix or continuous phase, with the elastomer and ionomer providing different phases.
  • the matter of which phase is formed by elastomer and which by ionomer depends upon a multiplicity of factors, including the relative proportions of elastomer and ionomer, their respective identities, and their respective properties.
  • the continuous phase is accordingly understood as comprising the amount of continuous phase polymer, relative to the amount of discontinuous phase polymer, so that the former is maintained as the continuous phase, with the latter dispersed therein as the discontinuous phase.
  • the dispersed phase can comprise clusters randomly distributed within the continuous phase. These clusters can be significantly smaller than would be the case if the compatibilizer were absent from the composition.
  • the compatibilizing agent can act in the composition to reduce interfacial tension. Accordingly, the presence of compatibilizer can lead to a decrease in the size of clusters. In turn, this improved morphology can cause a directly related improvement in the mechanical properties of the composition.
  • the presence of this agent can serve to maintain the stability of the developed morphology of the blend of elastomer and ionomer. In this manner, the compatibilizer helps to maintain the material performance of the composition.
  • the compatibilizer also has a disadvantageous effect on the composition of the invention, in that it decreases the velocity of a golf ball having a cover prepared from the composition; this agent therefore lessens the distance which can be obtained with the ball.
  • the greater the amount of compatibilizer which is present in the composition the greater is the adverse effect on velocity, and therefore on distance.
  • composition of the invention include as little as possible of the compatibilizer.
  • the preferred amount of this component is that which is the minimum necessary to develop the desired morphology of the elastomer and the ionomer in their blended state.
  • the elastomer represents about 50 wt % or less, more preferably about 40 wt % or less, of the golf ball cover composition.
  • compatibilizing agent it has surprisingly been found that for a composition which includes compatibilizing agent, the mechanical properties, such as tensile strength and elongation, may be substantially lower than for the same composition without compatibilizing agent.
  • component (c) comprises at least one high acid ionomer including at least 16 weight percent, or about 18- 19 weight percent, or at least 19 weight percent, of an alpha, beta-unsaturated carboxylic acid.
  • the alpha, beta-unsaturated carboxylic acid comprises at least one member selected from the group consisting of acrylic acid and methacrylate.
  • the high acid ionomer has improved mechanical properties such as a higher flexural modulus than conventional hard and low acid ionomers. This allows the cover to maintain a high resilience and shear resistance, especially when the amount of the elastomer is greater than 40 wt % but still less than the maximum recommended limit.
  • component (c) comprises both a first high acid ionomer and a second high acid ionomer, each including at least 16 weight percent, or about 18-19 weight percent, or at least 19 weight percent, of an alpha, beta-unsaturated carboxylic acid. More preferably, the first high acid ionomer has acid groups neutralized by sodium ions and the second high acid ionomer has acid groups neutralized by zinc ions.
  • component (c) comprises a high acid ionomer including about 18-19 weight percent, or at least 19 weight percent, of an alpha, beta- unsaturated carboxylic acid, with this high acid ionomer comprising acid groups neutralized by magnesium ions
  • this high acid ionomer with neutralization by magnesium ions can be used as a substitute for the above discussed combination of sodium-neutralized and zinc-neutrahzed ionomers, that is, for a composition including specific amounts of the sodium-neutralized and zinc-neutrahzed ionomers, instead there can be used an amount of magnesium-neutralized ionomer which is equal, or about equal, to the sum of the weight percents of the sodium and zinc ionomers
  • an elastomer particularly a soft elastomer, comprising at least one member selected from the group consisting of polyamide elastomers and polyester elastomers, and
  • (n) (0 has a hardness greater than the hardness of the elastomer, (n) includes about 18 weight percent, or about 18-19 weight percent, or about 19 weight percent, or at least 19 weight percent, of an alpha, beta-unsaturated carboxylic acid, and (in) comprises acid groups neutralized by magnesium ions
  • this composition of the third embodiment comprises about 60 weight percent or less of the elastomer
  • this composition comprises the elastomer, and a remainder of the at least one ionomer
  • the elastomer and ionomer are present in relative proportions which provide the desired cover hardness
  • the invention is directed to a cover which includes the foregoing composition - particularly, to a cover which includes at least one thermoplastic layer made of the foregoing composition. Yet additionally in this third embodiment, the invention is directed to a golf ball which includes a core and this cover.
  • a two-piece golf ball has a core made of rubber, e.g., and a single-layer cover.
  • the combination of the core and cover materials provide a "hard” ball that is generally very rigid and confers a “hard” feel when the ball is struck with the club.
  • a wound golf ball generally has a thread wound core covered by a cover made of one or more thermoplastic layers.
  • a multi-piece golf ball has a solid core, made of rubber, e.g., covered by more than one thermoplastic layer. According to the invention, such multi-piece ball has a variety of improved characteristics.
  • a multi-piece ball can be constructed according to the invention which has properties similar to a wound ball but with more durability and with improved performance and greater distance.
  • the present invention also relates to a golf ball including a core and a cover and further at least one mantle layer disposed between the core and the cover, wherein the mantle includes at least one layer that has a material selected from the group consisting of a thermoplastic polyetherester, polyamide based copolymer, an ionomer resin, thermoplastic polyurethane, metallocene polymer, and mixtures thereof.
  • the core is a solid rubber core that has a PGA compression which varies as a function of the core size, in the following manner: between 70 to 95, for a core diameter comprised between 1.56 to 1.60 inches; between 50 to 80, for a core diameter comprised 1.43 to 1.56 inches; and between 35 to 70, for a core diameter comprised between 1.39 to 1.43 inches.
  • the golf ball maintains a good feel at impact with, in particular, the long clubs. It is important to note that the excellent properties of the cover of the invention renders possible the use of such a core.
  • Figs. 1-7 are Scanning Electron Microscope (SEM) micrographs of compositions of the invention, at a magnification of 1 ,000.
  • Fig. 8 is a cross sectional view of a golf ball according to the present invention.
  • Fig. 9 is a cross sectional view of a multi-piece golf ball according to the present invention.
  • Copolymers are understood as including both those polymers incorporating two different monomeric units, as well as polymers incorporating three or more different monomeric units, e.g., terpolymers, etc.
  • a first embodiment of the invention pertains to a blend, particularly to a thermoplastic blend, having two main components: a relatively soft amide block copolymer; and an ionomer which has a hardness higher than the hardness of the amide block copolymer.
  • This first embodiment also pertains to a golf ball cover layer which includes this blend.
  • this first embodiment pertains to a golf ball comprising a core and a cover which comprises this blend.
  • the amide block copolymer is chosen from among the soft grades of hardness, i.e., less than or equal to 40 shore D (according to ASTM D-2240).
  • the amide block copolymer has a hardness of about 25 shore D (according to ASTM D-2240).
  • the choice of a low hardness of amide block copolymer enables a relatively wide range of hardness of the final cover to be encompassed, while simultaneously not affecting the properties of resilience of the final cover.
  • the polyamide-based copolymer of the invention comprises or consists preferably of a polyether block amide (PEBA).
  • PEBA polyether block amide
  • the structure consists of a regular linear chain of rigid polyamide segments interspaced with flexible polyether segments.
  • the polyamide segments are linked to an adjacent polyether segment by an ester group to form a polyetheresteramide.
  • Suitable thermoplastic polyetheramides are chosen from among the family of Pebax, which are available from Elf-Atochem Company. Preferably, the choice can be made from among Pebax 2533, 3533, 4033 and 1205. Blends or combinations of Pebax 2533, 3533 4033 and 1205 can also be prepared, as well.
  • Pebax 2533 has a hardness of about 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).
  • Pebax 3533 has 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). Pebax has the remarkable and probably unique property of increasing in resilience while decreasing in hardness. Pebax 4033 has a hardness of about 40 shore D (according to ASTM D-2240), a Flexural Modulus of 13 Kpsi (according to ASTM D-790), and a Bayshore resilience of about 51 %, (according to ASTM D-2632).
  • Pebax 1205 also has a hardness of about 40 shore D (according to ASTM D-2240) and a Flexural Modulus of 1.13 Kpsi (according to ASTM D-790). Where Pebax 4033 and/or Pebax 1205 are used, it is preferable that they be employed in small amounts. Particularly, a small amount of Pebax 4033 or 1205 and other Pebax of lower hardness is suitable as long as the total hardness remains in the determined limits. It is noted that the shore hardness of Pebax varies little with the temperature between -40°C and +80°C. The given values are determined at room temperature, between about 18 and 23 °C.
  • the second main component of the blend in this first embodiment of the invention, is an ionomer or a mixture of ionomers.
  • the ionomer or mixture of ionomers must have a hardness value which is greater than the hardness value of the first main component. More preferably, the hardness of the second main component must be at least 65 shore D.
  • the preferred ionomers suitable to reach these properties are the high flexural ionomers with a flexural modulus of at least 60,000 psi. More precisely, these ionomers are chosen among the acid ionomers, particularly the high acid ionomers.
  • high acid ionomers are designated as ionic copolymers which are the metal, e.g., sodium, zinc, lithium, magnesium, etc., salts of the reaction product of an olefin having about 2 to 8 carbon atoms and an unsaturated monocarboxylic acid having from about 3 to 8 carbons atoms.
  • the ionomeric resins are copolymers of ethylene and either acrylic or methacrylic acid.
  • the carboxylic acid groups of the copolymer are partially neutralized (i.e., approximately 10-75%) by the metal ions.
  • the high acid ionomer must contain at least 16%>, or about 18%), or about 18-19%), or about 19%, or at least 19%), by weight of the carboxylic acid.
  • the high acid ionomers include high acid ionomers such as those developed by E.I. DuPont de Nemours & Company under the trademark “Surlyn ® " and by Exxon Corporation under the trademarks ⁇ scoX' or "lotek", or a blend thereof.
  • high acid ionomers which can be used for the invention are Surlyn ® 9120, 8140, AD8546 and AD8552 (Surlyn ® AD8552 currently being commercially available as Surlyn 6 ® 120). These grades can be used alone or in a mixture thereof
  • Bayshore Resilience is measured with a Bayshore resiliometer after a sample of material is placed into the base of the test fixture. A plunger is dropped down from a controlled height of 17V_ inches. The plunger hits the test slab and rebounds back toward its original position. This rebound is measured at its highest point and is recorded as a function of the percentage rebound.
  • the high acid ionomers are very stiff and hard materials.
  • a cover made of pure high acid ionomer is felt as extremely hard and it imparts a very low spin rate to the ball, which causes difficulty in controlling the ball at the approach to the green. Also, it cannot withstand multiple impacts against a long club such as a driver and the like.
  • the high acid ionomer comprises groups partially neutralized by lithium. Ionomer with lithium gives a maximum of rebound at impact in comparison with other high acid ionomers.
  • the compound of which the cover is comp ⁇ sed can advantageously include other mate ⁇ als to ensure proper blending and mixing between the amide block copolyether and the ionomer and to achieve the optimized mechanical and physical properties of the cover.
  • the range of hardness for the cover can be fitted at a desired value between 40 and 65 shore D, while the Bayshore resilience remains at very high value in comparison with the VLMI/high acid ionomer composition.
  • Table 1 Illustrated in the following table (Table 1) are a number of batch formulations for several cover compositions of the present invention as well as specific characte ⁇ stics of these formulations These five examples are designated as PB-10 to PB-90 As shown in the table, the examples PB-10 to PB-90 comprise different covers made of a mixture of a
  • Surlyn 8320 The general and mechanical characteristics of Surlyn 8320 are as follows:
  • formulation components were mixed at room temperature in a tumbler mixer for 30 minutes.
  • the covers were injection molded around the core at a temperature of injection between 250 and 500 °F, depending upon the blend injected.
  • the two-piece ball comprises a cover having a single layer and a polybutadiene core of 1.55 inches and PGA compression of 70.
  • the external diameter of the ball is between 1.680 to 1.686 inches, in conformance with the USGA rules.
  • a comparative example is also given with a ball having a cover made from balata available in the market under the name "Tour Balata” from Acushnet Company.
  • example PB-50 of the invention shows an increase of about 5% of the spin rate when the ball is hit by a d ⁇ ver, which mainly results in a benefit of about 2 7% in distance with lespect to example VM-70
  • the improvement in spin rate is of about 7%o when the ball is hit with an 8- ⁇ ron
  • Table 2 gives test results for three examples of golf balls, 1 e , examples PB-A, PB-B, PB-C, which have covers made of pure
  • the 8-iron test was set up with a Taylor Made "Burner” iron, tested at a swing speed of 88 mph. Backspin is measured initially as the ball leaves the club face.
  • the (a) elastomer, (b) compatibilizing agent, and (c) ionomer are hereinafter discussed
  • the at least one ionomeric polymer, or ionomer, of component (c) is understood as encompassing the copolymers of an alpha-olefin and an unsaturated - particularly, an alpha, beta-unsaturated - carboxylic acid whose carboxylic functions are partly neutralized by a metal ion
  • This polymer may also include another monomer such as an alkyl
  • lonomenc polymers of the present invention are understood as including acid ionomers such as high acid ionomers and low acid ionomers
  • the high acid ionomers are understood as comprising at least 16 wt %, or about 18 wt %, or about 18-19 wt %, or about 19 wt %, or at least 19 wt %, carboxylic acid - particularly unsaturated carboxylic acid, and more particularly alpha, beta-unsaturated carboxylic acid - and the low acid ionomers are understood as comp ⁇ sing less than 16 wt % carboxylic acid
  • the ionomers of the invention are understood as including ionomers having a flexural modulus of about 20,000 to 60,000 psi (according to ASTM D-790), and also as including ionomers having a flexural modulus of about 60,000 psi or greater (according to ASTM D-790)
  • the former of these ionomers are understood as including the low acid ionomers, and the latter are understood as including the high acid ionomers
  • Suitable ionomeric resins include those as disclosed in the International Publications Nos WO 96/40377 and WO 97/02318, and in U S Patent No 5,591,803, the disclosures of which are hereby incorporated herein in their entireties by reference thereto
  • Appropriate alpha-olefins include ethylene, propylene, 1-butene, and 1-hexene.
  • suitable unsaturated carboxylic acids are acrylic acid, and also methacrylic, ethacrylic, alphachloroacrylic, crotonic, maleic, fumaric and itaconic acid.
  • the ionomeric polymer of the invention is a copolymer of ethylene comprising about 0 to 25 wt %, preferably about 0 to 2 wt % of alkyl (meth)acrylate, and about 5 to 35 wt %>, preferably about 15 to 35 wt % of (meth)acrylic acid, in which about 1 to 90 % of the carboxylic groups are neutralized to form an ionomer with a cation such as, for example, lithium, sodium, potassium, magnesium, calcium, barium, lead, zinc, tin, aluminum, or a combination of two or more of these cations.
  • the proportion of acid is preferably at least about 16 wt %, or about 18 wt %>, or about 18-19 wt %, or about 19 wt %, or at least about 19 wt %.
  • ionomers with at least 16 wt %> of acid are known as the "high acid” ionomers and they are prefe ⁇ ed in the present invention since they confer more speed to the golf ball without sacrificing the spin properties of the ball. It has also been found out that synergistic properties result from including more than one high acid ionomer in the composition. Preferably, two high acid ionomers are preferred. More preferably, a combination of a zinc high acid ionomer and a sodium high acid ionomer has given the best results.
  • the alkyl group of the alkyl (meth)acrylate may comprise up to 18 carbon atoms.
  • suitable alkyl (meth)acrylates include methyl, ethyl, n-butyl and isobutyl (meth)acrylate.
  • These resins preferably have a flexural modulus of between about 500 and 150,000 psi (according to ASTM D-790). Their hardness may be between about 20 and 80 shore D (according to ASTM D-2240). Their Melt Flow Index may be between about 0.2 and 10 g/10 min (ASTM D-1238).
  • the proportion of acid m the ionomer is preferably about 18 weight percent, or about 18-19 weight percent, or about 19 weight percent, or at least 19 weight percent
  • a magnesium high ionomer can be used their place where this substitution is employed, preferably the amount of the magnesium high ionomer is equal, or about equal, to the total amount of the zinc and sodium high ionomers that have been replaced
  • a particular substitution which can be made is that of Surlyn AD8552 for the Surlyn 9120/Surlyn 8140 combination
  • the ionomer or mixture of ionomers preferably have a hardness value which is greater than the hardness value of the elastomer component
  • the hardness of the ionomer or mixture of ionomers more preferably is at least about 65 shore D (according to ASTM D-2240)
  • the prefe ⁇ ed ionomers suitable to reach these properties are the high flexural ionomers with a flexural modulus of at least about 60,000 psi (according to ASTM D-790) More precisely, these ionomers are chosen from among the acid ionomers, particularly the high acid ionomers.
  • the acid ionomers including the high acid ionomers, are designated as ionic copolymers which are the metal - e.g., one, or two or more in combination, of sodium, zinc, lithium, potassium, magnesium, calcium, barium, lead, tin, aluminum, etc. - salts of the reaction product of an olefin having about 2 to 8 carbon atoms and an unsaturated monocarboxylic acid having about 3 to 8 carbon atoms.
  • the ionomeric resins are copolymers of ethylene and either acrylic or methacrylic acid.
  • the carboxylic acid groups of the copolymer are partially neutralized (i.e., approximately 10-75%) by the metal ions.
  • the high acid ionomer contains 16% or more, preferably about 18- 19 %, or 19%) or more, by weight of the carboxylic acid, and the low acid ionomer contains less than ⁇ 6% by weight of the carboxylic acid.
  • the high acid ionomers include high acid ionomers such as those developed by E.I.
  • the high acid ionomers which can be used for the invention are Surlyn 9120, 8140, AD8546 and AD8552. These grades can be used alone or in a mixture thereof.
  • the elastomer component may include one or more polyamide elastomers, and/or one or more polyester elastomers.
  • Preferred polyamide and polyester elastomers of the invention include the soft polyamide and soft polyester elastomers.
  • the soft elastomers are preferably those having a hardness of about 35-40 shore D or less, more preferably 25-35 Shore D (according to ASTM D-2240).
  • Preferred polyamide elastomers of the invention include the block amide polyethers which result from the copolycondensation of polyamide blocks having reactive chain ends with polyether blocks having reactive chain ends, including:
  • polyamide blocks of dicarboxylic chain ends come, for example, from the condensation of alpha-omega aminocarboxylic acids of lactam or of carboxylic diacids and diamines in the presence of a carboxylic diacid which limits the chain length.
  • the polyamide blocks are polyamide- 12.
  • the molecular weight of the polyamide sequences is preferably between about 300 and 15,000, and more preferably between about 600 and 5,000.
  • the molecular weight of the polyether sequences is preferably between about 100 and 6,000, and more preferably between about 200 and 3,000.
  • the amide block polyethers may also comprise randomly distributed units. These polymers may be prepared by the simultaneous reaction of polyether and precursor of polyamide blocks. For example, the polyether diol may react with a lactam (or alpha-omega ammo acid) and a diacid which limits the chain m the presence of water There is obtained a polymer having mamly, polyether blocks, polyamide blocks of very vanable length, but also the various reactive groups having reacted in a random manner and which are distributed statistically along the polymer chain
  • Suitable amide block polyethers include those as disclosed in U S Patents Nos 4,331,786, 4,115,475, 4,195,015, 4,839,441, 4,864,014, 4,230,838, and 4,332,920 These patents are incorporated herein in their entireties, by reference thereto
  • the polyether may be, for example, a polyethylene glycol (PEG), a polypropylene glycol (PPG), or a polytetramethylene glycol (PTMG), also designated as polytetrahydrofurane (PTHF)
  • PEG polyethylene glycol
  • PPG polypropylene glycol
  • PTMG polytetramethylene glycol
  • PTHF polytetrahydrofurane
  • the polyether blocks may be along the polymer chain in the form of diols or diamines However, for reasons of simplification, they are designated PEG blocks, or PPG blocks, or also PTMG blocks
  • the polyether block comprises different units such as units which derive from ethylene glycol, propylene glycol, or tetramethylene glycol
  • the amide block polyether comp ⁇ ses only one type of polyamide block and one type of polyether block Mixing of two or more polymers with polyamide blocks and polyether blocks may also be used
  • the amide block polyether is such that it represents the major component in weight, l e , that the amount of polyamide which is under the block configuration and that which is eventually distributed statistically in the chain represents 50 weight percent or more of the amide block polyether.
  • the amount of polyamide and the amount of polyether is in a ratio (polyamide/polyether) of 1/1 to 3/1.
  • polyamide elastomers of the invention are the polyetheramide elastomers. These include the suitable thermoplastic polyetheramides as discussed herein.
  • Suitable polyester elastomers of the invention include polyetherester elastomers and polyesterester elastomers. Of these, the polyetherester elastomers are prefe ⁇ ed.
  • G130D, G135D, and G140D from Sunkyong Industries, Seoul, Korea, and HYTREL G3078, G3548, and G4074 from DuPont.
  • Component (b), in the second embodiment of the invention may include one, or two or more, compatibilizing agents.
  • the indicated at least one monomer can comprise one or more cyclic functional groups, and/or one or more noncyclic functional groups.
  • the compatibilizing agent comprises a copolymer which comprises at least one monomer comprising a cyclic functional group, or two or more cyclic functional groups. Also in this embodiment, the compatibilizing agent preferably comprises about 0.3 to 10 wt % of the composition of the invention.
  • this monomer may comprise one or more of an epoxy monomer, maleic anhydride, norbornene, norbornadiene, dicyclopentadiene, and oxazoline.
  • this monomer comprises an epoxy monomer.
  • the epoxy group of the epoxy monomer comprises an unsaturated epoxy group which shows very good chemical activity with terminal point of unsaturation capable of undergoing polymerization reactions with the other components in the composition and particularly the ionomer and the elastomer previously defined.
  • the functional group undergoes one or both of physical reaction and chemical reaction, with the elastomer and or with the ionomer, to reduce the interfacial tension.
  • the copolymer comprises an epoxy monomer which includes an unsaturated epoxy group
  • the different components be chosen so that the interaction which occurs includes reaction of the epoxy group with free carboxyl groups in the ionomer, and also with amide groups in the polyamide elastomer or with the ester groups in the polyester elastomer, to bring uniform or homogenous dispersion of the elastomer when the ionomer comprises the matrix or continuous phase. This dispersion improves the desirable mechanical properties of a golf ball cover.
  • the copolymer also preferably comprises an alphaolefin having 30 carbon atoms.
  • Suitable alphaolefins include ethylene, propylene, 1-butene, 1-pentene, 3-methyl-l -butene, 1 -hexene, 4-methyl-l-pentene, 3-methyl-l-pentene, 1-octene, 1-decene, 1-dodecene, 1- tetradecene, 1 -hexadecene, 1-octadecene, 1 -eicocene, 1 -dococene, 1 -tetracocene, 1- hexacocene, 1 -octacocene, and 1-triacontene.
  • These alphaolefins may be used alone or in blend of two or more alphaolefins.
  • the functional monomer preferably comprises an epoxy group.
  • Prefe ⁇ ed embodiments include the following:
  • esters and ethers of aliphatic glycidyl such as allylglycidylether, vinylglycidylether, glycidyl maleate and itaconate, glycidyl acrylate and methacrylate, and - alicyclic glycidyl ester and ether such as the 2-cyclohexene-l-glycidylether, the cyclohexene-4.5-diglycidylcarboxylate, the cyclohexene-4-glycidyl carboxylate, the 5- norbornene-2-methyl-2-glycidyl carboxylate, and the endocis-bicyclo(2,2, 1 )-5-heptene-2,3- diglycidyl dicarboxylate.
  • aliphatic glycidyl such as allylglycidylether, vinylglycidylether, glycidyl maleate and itaconate, glycidyl
  • Component (b) may yet additionally comprise other monomers.
  • Those which are suitable include esters of unsaturated carboxylic acid, for example, alkyl (meth)acrylates or vinylic esters of unsaturated carboxylic acids.
  • the functional monomer may be copolymerized with the alphaolefin, and eventually with other monomers, or may be grafted with homo- or copolymers.
  • Polyolefin intends to cover polymers having at least one unit of alphaolefin among those cited herein below, for example:
  • HDPE high density polyethylene
  • LDPE low density polyethylene
  • LLDPE linear low density polyethylene
  • VLDPE very low density polyethylene
  • polyethylene obtained by metallocene catalysis i.e., polymers obtained by copolymerization of ethylene and alphaolefin such as propylene, butene, hexene or octene in the presence of a monosite catalyst constituted generally of a zirconium or titanium atom and two alkyl cyclic molecules bonded to the metal.
  • a monosite catalyst constituted generally of a zirconium or titanium atom and two alkyl cyclic molecules bonded to the metal.
  • the metallocene catalysts are usually composed of two cyclopentadiene cyclic groups bonded to the metal atom. These catalysts are frequently used with aluminoxanes such as cocatalysts or activators, preferably the methylaluminoxane (MAO).
  • MAO methylaluminoxane
  • the hafnium may also be used as a metal on which the cyclopentadiene is bonded.
  • Other metallocene catalysts may include transition metals of the groups IV A, V A, and VI A. Metals of the series of the lanthamides may also be used.
  • alphaolefins are:
  • this grafting can be effected by heating the polymers at a high temperature, from around 150° C to 300° C, optionally in the presence of a solvent with or without free radicals.
  • Suitable solvents which may be used in this reaction are benzene, toluene, xylene, chlorobenzene, cumene, etc.
  • Suitable free radicals which may be used include t-butyl-hydroperoxide, di-t-butyl-peroxide, t-butyl-cumyl-peroxide, dicumyl- peroxide, l,3-bis-(t-butylperoxy-isopropyl)benzene, acetyl-peroxide, benzoyl-peroxide, iso-butyryl-peroxide, bis-3,5,5-trimethyl-hexanoyl-peroxide, and methyl-ethyl-cetone- peroxide.
  • the amount of grafted monomer may be chosen in an appropriate manner but preferably is about 0.01 to 10%, more preferably about 0.1 to 5 wt %, with respect to the weight of the grafted polyolefin.
  • the following terpolymers are obtained by direct copolymerization by opposition to grafted copolymers:
  • the unsaturated epoxy is the glycidyl (meth)acrylate.
  • the amount of epoxy may comprise about 1 to 15 wt %, preferably 10 wt % or less of component (b).
  • the amount of alkyl (meth)acrylate or vinylic ester may comprise about 5 to 40 wt % of component (b).
  • the alkyl (meth)acrylate may be chosen from among the (meth)acrylates previously cited for the ionomer of component (c).
  • Terpolymers comprising epoxy monomers - specifically, containing epoxy functional groups - and which are suitable for the invention, may include LOTADER® AX 8900, AX 8840, and AX 8920, sold commercially by Elf-Atochem Company, ELVALOY, sold commercially by DuPont, IGETABOND (formerly sold as BONDFAST), sold commercially by Sumitomo Chemical Co , and REXPEARL, sold commercially by Nippon Petrochemicals Co , Ltd
  • the viny c ester is preferably vinyl acetate
  • epoxy functional copolymers include ESBS A1005, ESBS A1010, ESBS A1020, ESBS AT018, and ESBS AT019 All of these are available from Daicel Chemical Industries, Ltd.
  • the indicated at least one monomer comprising one or more cyclic functional groups may comprise maleic anhydride
  • suitable maleic anhydride copolymers include maleic anhydride-modified ethylene-propylene copolymers, maleic anhyd ⁇ de-modified ethylene-propylene-diene monomer te ⁇ olymers, maleic anhydride-modified polyethylenes, maleic anhydnde- modified polypropylenes, ethylene-ethyl acrylate-maleic anhyd ⁇ de te ⁇ olymers, and maleic anhyd ⁇ de-indene-styrene-cumarone copolymers
  • Commercially available copolymers which are suitable for the invention, and which contain maleic anhydride include the following:
  • BONDINE AX8390 which is an ethylene-ethyl acrylate-maleic anhydride te ⁇ olymer having an ethylene acrylate + maleic anhydride content of 32 wt %
  • BONDINE TX8030 which is an ethylene-ethyl acrylate-maleic anhydride te ⁇ olymer having an ethylene acrylate + maleic anhydride content of 15 wt % and a maleic anhydride content of 1-4 wt %;
  • polarity and branching of the acrylic ester improves wettability and flexibility, and lowers crystallinity.
  • polarity and reactivity of the maleic anhydride result in chemical adhesion.
  • the indicated at least one monomer comprising one or more cyclic functional groups may comprise oxazoline.
  • the oxazoline copolymers include two types of thermoplastic resins containing oxazoline groups - polymers which have oxazoline groups situated at the surface of the polymer particles, and polymers wherein the oxazoline groups are added to the polymer backbone, both of these types are suitable for the present invention
  • Each of these two types of oxazoline polymers includes polystyrenes, acrylonit ⁇ le-styrene copolymers, acrylic acid- styrene copolymers, polymethyl methacrylates, polyethyl methacrylates, polybutyl methacrylates, polymethyl acrylates, and polybutyl acrylates
  • copolymers which are suitable for the invention, and which contain oxazoline, include the following, all commercially available from Nippon Shokubai Kagaku Kogyo K K
  • EPICROSS RASIOOI which is an acrylonit ⁇ le-styrene copolymer comprising oxazoline groups, and which has a weight average molecular weight of about 120,000 and a polyfunctional group (oxazoline group) equivalent molecular weight of about 2,200,
  • EPICROSS RPS1001 which is a polystyrene comprising oxazoline groups, and which has a w eight average molecular weight of about 120,000 and a polyfunctional group (oxazoline group) equivalent molecular weight of about 1 1 ,000, and
  • EPICROSS RPS1005 which is a polystyrene comprising oxazoline groups, and which has a weight average molecular weight of about 140,000 and a polyfunctional group (oxazoline group) equivalent molecular weight of about 2,200
  • the compatibilizing agent comprises a copolymer which comp ⁇ ses at least one monomer comprising a noncyclic functional group, or two or more noncyclic functional groups Suitable noncyclic functional groups include carboxylic acid groups and ammo groups Also in this embodiment, the compatibilizing agent preferably comprises 10 wt % or less, or less than 10 wt %, of the composition of the invention.
  • the elastomer component of the second embodiment is suitable.
  • Ionomers which are appropriate for the third embodiment include particularly the magnesium ionomers of the second embodiment which comprise about 18 wt %, or about 18-19 wt %, or about 19 wt %>, or at least 19 wt %, carboxylic acid - particularly unsaturated carboxylic acid, and more particularly alpha, beta-unsaturated carboxylic acid.
  • the third embodiment composition may include compatibilizing agent, as discussed for the second embodiment; however, preferably compatibilizing agent is absent, or essentially absent or substantially absent, from the composition of the third embodiment of the invention.
  • the amount of the polyamide elastomer and/or polyester elastomer preferably remains at or under about 50 wt %, more preferably between about 30 and 40 wt %. Also as a matter of preference, the amount of elastomer is at least that which is sufficient so that the composition is in the form of a discontinuous phase dispersed within a matrix or continuous phase, with the elastomer and ionomer providing different phases.
  • the polyamide elastomer and/or polyester elastomer have the property of increasing in resilience while decreasing in hardness. Therefore, the polyamide elastomer and/or polyester elastomer have also to be chosen from among the soft grades to confer to the composition remarkable properties of both softness and resilience.
  • the hardness of component (a) is about 35 shore D or lower (according to ASTM D-2240).
  • the ionomeric polymer of component (c) has a hardness greater than that of the amide block polyether, to compensate for its softness and to take advantage of the high resilience of the high grades of ionomers.
  • the hardness of component (c) is about 65 shore D or higher (according to ASTM D-2240).
  • the hardness of the composition preferably is targeted to be between about 50 and 65 shore D (according to ASTM D-2240), so that it confers sufficient properties of control and a good feel, as well as performance in distance and initial velocity.
  • a prefe ⁇ ed means of achieving a hardness value within this range is to utilize elastomer and ionomer components having the appropriate relative hardness values, and in the necessary relative proportions, so as to provide the desired hardness value for the composition.
  • the ionomer which is used has a hardness value of about 65 shore D or greater (according to ASTM D-2240).
  • the elastomer has a hardness value of about 35 shore
  • SURLYN 9120 is an ionomer resin as discussed herein.
  • LOTADER AX 8900 identifies a te ⁇ olymer of ethylene, n-butyl acrylate, and glycidyl methacrylate produced by Elf-Atochem Co.
  • 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).
  • Bl and B6 are comparative examples which do not include the epoxy compound of component (b).
  • B2 to B5 show various blends of the invention, each having a different amount of the epoxy compound for the given relative proportions of PEBAX 2533/Surlyn 9120.
  • B7 to B10 show other various blends of the invention, again with each blend having a different amount of the epoxy compound, but in this case for another choice of relative proportions of PEBAX 2533/Surlyn 9120.
  • T REAR 190° C
  • T CE TER 205 ° C
  • T FR0NT 180° C
  • T DIE 190° C.
  • twin screw extruder The use of a twin screw extruder is prefe ⁇ ed, and has shown much improved mechanical results, in particular with regard to the resulting golf balls' durability against cracking.
  • the use of a twin screw for extrusion is highly recommended to obtain a homogeneous compound with optimal mechanical properties.
  • the polymer mixtures or blends can also be made by dry blending or by other internal mixers, such as a single screw extruder, a kneader, or a Banbury mixer.
  • PEBAX 2533 (component (a)) being greater than the prefe ⁇ ed relative amount for the present invention.
  • B 1 1 and B 16 are reference blends without compatibilizer or epoxy compound.
  • B 12 to B15 are for comparison to Bl 1 with variation of the amount of the compatibilizer for a particular proportional ratio of PEBAX/Surlyn.
  • B17 to B20 are for comparison to B16 for a different proportional ratio of PEBAX/Surlyn.
  • test specimens ("dog bones" complying with ASTM D-638) were prepared, using an injection molding machine comprising a ba ⁇ el with heating sections and a nozzle connected to a mold
  • golf balls were produced to carry out a shear resistance test and confirm the improvement in shear resistance of a cover made in accordance with the present invention.
  • Two golf balls for each cover composition were shot twice with a sand wedge type iron "Taylor Made Tour 55", having the following physical characteristics: Lie: 64°; Loft: 55 °; bounce: 8°; club length: 35 inches.
  • a visual evaluation was made according to the following criteria:
  • the results show a significant improvement of the shear resistance when the cover formulation comprises a certain amount of Lotader.
  • An impact durability test was also conducted which consisted of firing a golf ball via an air cannon at 125 feet/second inbound velocity into a stationary steel plate (Conventional test machine usually used to measure golf ball coefficient of restitution (COR)).
  • COR golf ball coefficient of restitution
  • the balls strike the wall at simulated "driver" conditions, then they are periodically checked for cracks. Twelve golf balls are used for one reference, and failure is based on cracks on 50 % of the balls.
  • Example A2 shows significant improvement of the coefficient of restitution (COR) while the spin rate remains substantially stable when compared to the results obtained with Examples A4 and A5, respectively.
  • Example C is given for comparative pu ⁇ oses.
  • the tested golf balls were 3-piece balls comprising a core, a thermoplastic mantle and a cover.
  • the invention may apply, as well, to a 2-piece golf ball consisting of a core and a cover.
  • Examples A1-A5 and C are the same as the corresponding Examples A1-A5 and C of Table 6, except that for each of the Table 7 Examples, the mantle has 30 weight percent Surlyn AD 8552, instead of the 15 weight percent Surlyn 9120 and 15 weight percent Surlyn 8140 specified for each Example in Table 6. In each of these instances, the amount of Surlyn AD8552 is equal to the total amount of Surlyn 9120 and Surlyn 8140 which is replaced.
  • the Lotader is included with the Surlyn AD8552, because inclusion of the Lotader with Surlyn AD8552 in the cover results in even greater shear resistance than is obtained from using Surlyn AD8552 without the Lotader.
  • inclusion of the Lotader with the Surlyn AD8552 generally improves mechanical properties over those exhibited by the Surlyn AD8552 without the Lotader For instance, greater reduction of surface tension and mterfacial tension, and improvements in tensile strength and elongation, are all realized where the Lotader is also present
  • Diameter (in inches) 1.48 1.48 1.48 1.48 1.48 1.48 .48 .48 .48 .48
  • Thickness (in inches) 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05
  • Surlyn AD8552 is a high acid ionomer with a flex modulus of 75kpsi and 1 wt % acid. ** Surlyn 7930 is a hard ionomer with a flex modulus of 462 MPa and 16 wt % acid. *** Surlyn 9120 is a high acid ionomer with a flex modulus of 440 MPa and 19 wt % acid. **** Surlyn 8140 is a high acid ionomer with a flex modulus of 545 MPa and 19 wt % acid. Surlyn 9320 is a VLMI having a flex modulus of 26 Mpa.
  • Thickness (in inches) 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 co Hardness (Shore D) 46 46 46 46 46
  • AD8552 is a high acid ionomer with a flex modulus of 75kpsi and 19 wt % acid.
  • Surlyn 7930 is a hard ionomer with a flex modulus of 462 MPa and 16 wt % acid.
  • Surlyn 9120 is a high acid ionomer with a flex modulus of 440 MPa and 19 wt % acid.
  • Surlyn 8140 is a high acid ionomer with a flex modulus of 545 MPa and 19 wt % acid.
  • Surlyn 9320 is a VLMI having a flex modulus of 26 MPa.
  • Figs 1-5 provide particularly direct evidence, of the compatibihzation and decrease in discontinuous or dispersed phase size, resulting from the presence of compatibilizing agent
  • all of Figs 1-5 exhibit ductile fractured surfaces
  • Fig 1 showing a blend without compatibilizer, displays gross phase separation with an obvious shear line development, in the form of fiber-like structures along the shear
  • Figs 2-5 depict less obvious fiber-like structures and smaller dispersed minor phases - in fact, less than 1 ⁇ m in size, which is significantly smaller than what is shown in Fig 1
  • Polymer blends form a multiphase system with a defo ⁇ nable minor phase
  • an in situ mo ⁇ hology can be developed, e g , an optimally dispersed phase size and adequate mte ⁇ hase adhesion, which are directly related to useful mechanical properties
  • many properties such as impact strength, tensile strength, and impermeability to solvent, can be improved
  • a proper mterfacial agent compatibilizer
  • compositions of the foregoing batches show the development of a desirable in situ mo ⁇ hology m Pebax/Surlyn polymer blend systems provided by twin screw extrusion, in the presence of a compatibilizer
  • Figs 6 and 7 also provide particularly direct evidence, of the compatibihzation and decrease in discontinuous or dispersed phase size, resulting from the presence of compatibilizing agent
  • the former is preferably provided in the range of about 10% to about 15%, more preferably about 12%) to about 12 5%, of the latter
  • the compatibilizer is present in an amount of about 10% of the elastomer
  • the compatibilizer is present in an amount of about 12.5% of the elastomer.
  • FIG. 8 shows a golf ball of the invention having a core 20 and a cover 22 having a single layer.
  • the core 20 is preferably a solid piece having a spherical configuration circumscribed by a cover 22 of determined thickness.
  • the core is formed of a rubber composition of a base rubber blended with a co-crosslinking agent, a peroxide and a filler by a compression process including heating, pressing and shaping procedure.
  • the rubber core can also be produced by the method of injection molding.
  • a prefe ⁇ ed base rubber is 1 ,4-polybutadiene having a cis structure of at least 40 wt %. More preferably, the cis structure represents at least 90 wt % of the 1,4- polybutadiene. Other various rubbers including natural and synthetic rubbers can be added to the 1,4-polybutadiene.
  • the crosslinking agent includes a metal salt of an unsaturated fatty acid such
  • zmc salt a magnesium salt of unsaturated fatty acid such as methacry c acid, acrylic acid and ester compounds
  • Polybutadiene rubber is prepared with a rare earth element catalyst, such as neodymium (Nd)
  • a rare earth element catalyst such as neodymium (Nd)
  • Nd neodymium
  • the core has a specific gravity of 1 05 and higher and a PGA compression which varies depending upon the size of the core so as to confer a soft feel to the ball More precisely, the PGA compression of the core is compnsed between 70 to 95, for a core diameter between 1 56 to 1 60 inches, between 50 to 80, for a core diameter between 1 43 to 1 56 inches, and between 35 to 70, for a core diameter between 1 39 to 1 43 inches.
  • the PGA compressions of core are measured with an ATTI compression gauge known by one skilled in the art
  • FIG 9 shows a multi-piece ball of the invention
  • the golf ball compnses a core
  • the material chosen for the mantle can be made from among a wide variety of thermoplastic or vulcanized mate ⁇ als However, it is prefe ⁇ ed that the mantle comprises at least one layer that includes a material selected from the group consisting of thermoplastic polyetheresters, polyamide elastomers, ionomer resins, thermoplastic polyurethanes, metallocene polymers, vulcanized elastomers, and mixtures thereof.
  • the polyamide elastomers are prefe ⁇ ed the polyetheresteramides.
  • Suitable mantle compositions include those of the Examples shown in Tables 6 and 7 herein.
  • the cover compositions of the invention can also include, in suitable amounts, one or more additional ingredients generally employed in golf ball cover compositions.
  • Agents provided to achieve specific functions, such as additives and stabilizers, can be present.
  • Ingredients which are suitable include UV stabilizers, photostabilizers, antioxidants, pigments, dispersants, mold releasing agents, and processing aids.
  • inorganic fillers can be added such as titanium dioxide (Ti0 2 ), calcium carbonate, zinc sulfide or zinc oxide for coloring pii ⁇ oses.
  • Additional fillers can be chosen to impart additional density to blends of the cover or any other part of the ball, such as zinc oxide or barium sulfate, tungsten carbite or lead powder.
  • any conventional technique may be used for covering the solid core with the cover and additionally with an intermediate mantle.
  • the layers can be directly applied by injection molding over the core at a temperature of 250 to 500°F for 30 to 120 seconds.
  • Another method comprises forming the layers into half-cups and then fitting the cups around the core, followed by compression fonriing.
  • compression molding the half-cups are preformed by injection molding into a conventional half-shell mold at 250 to 500 °F for a short time, between 30 to 60 seconds. Then, the half-cups are positioned around a core in a conventional compression molding device. Pressure and heat are applied for approximately 1 to 3 minutes. The ball is allowed to cool in the mold until the cover is hard solid enough to be removed without deforming.
  • the core is a solid rubber core, but the invention is not limited to such a core.
  • the core may also be a wound threaded structure.
  • the core may be manufactured as a combination of solid material for the center, such as rubber, su ⁇ ounded by wound thread, or may alternatively consist of a liquid or paste filled core su ⁇ ounded by wound thread.
  • the diameter of the central part of the wound core is about 1.0 to 1.125 inches and the total wound diameter is about 1.54 to 1.60 inches.
  • the golf ball undergoes conventional operations such as buffing, painting and stamping.
  • the golf ball can be prefrozen.

Abstract

L'invention concerne une composition d'enveloppe de balles de golf. Cette composition comprend un copolymère séquencé d'amide présentant une dureté inférieure ou égale à 40 shore D, et un ionomère présentant une dureté supérieure à la dureté du copolymère séquencé d'amide. Les quantités respectives en poids du copolymère séquencé d'amide et de l'ionomère dépendent de la dureté d'enveloppe voulue.
PCT/US1998/017231 1997-08-20 1998-08-20 Compositions pour enveloppes de balles de golf et balles de golf a enveloppes ameliorees WO1999008756A1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
AU89158/98A AU8915898A (en) 1997-08-20 1998-08-20 Compositions for golf ball covers, and golf balls with improved covers
JP2000509491A JP2003504089A (ja) 1997-08-20 1998-08-20 ゴルフボールカバー用組成物、及び改良されたカバーを具備するゴルフボール
GB0004076A GB2343123A (en) 1997-08-20 1998-08-20 Compositions for golf ball covers and golf balls with improved covers

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US91508197A 1997-08-20 1997-08-20
US08/915,081 1997-08-20
US7049798P 1998-01-05 1998-01-05
US60/070,497 1998-01-05

Publications (1)

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WO1999008756A1 true WO1999008756A1 (fr) 1999-02-25

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JP (1) JP2003504089A (fr)
AU (1) AU8915898A (fr)
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Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000043449A1 (fr) * 1999-01-22 2000-07-27 Spalding Sports Worldwide, Inc. Balle de golf contenant un gel
US6274669B1 (en) 1997-01-21 2001-08-14 Acushnet Company Golf ball cover compositions containing non-carboxylic acid polymeric compatibilizers
EP1170038A2 (fr) * 2000-06-06 2002-01-09 Dunlop Slazenger Group Americas Inc Materiau pour le revêtement d'une balle de golf à forte elasticité
US20100167845A1 (en) * 2008-12-23 2010-07-01 Kim Hyun J Golf ball
DE202010012480U1 (de) 2010-09-10 2011-12-12 M.A.C.'s Holding Gmbh Pinsel
US8372915B2 (en) 2008-10-10 2013-02-12 Sri Sports Limited Golf ball
US8399564B2 (en) 2008-12-26 2013-03-19 Sri Sports Limited Golf ball
US8399563B2 (en) 2008-10-08 2013-03-19 Sri Sports Limited Golf ball
US8501871B2 (en) 2008-07-11 2013-08-06 Dunlop Sports Co., Ltd. Golf ball
US9005050B2 (en) 2010-03-26 2015-04-14 Sri Sports Limited Golf ball
US9517385B2 (en) 2008-12-26 2016-12-13 Dunlop Sports Co., Ltd. Golf ball and process for preparing the same

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JP5135048B2 (ja) * 2008-04-28 2013-01-30 ダンロップスポーツ株式会社 ゴルフボール
JP5341414B2 (ja) * 2008-07-11 2013-11-13 ダンロップスポーツ株式会社 ゴルフボール
JP5119074B2 (ja) * 2008-07-24 2013-01-16 シャープ株式会社 トナーの製造方法およびトナー、現像剤、現像装置ならびに画像形成装置
JP5322571B2 (ja) * 2008-10-16 2013-10-23 ダンロップスポーツ株式会社 ゴルフボール
JP6965592B2 (ja) * 2017-06-22 2021-11-10 ブリヂストンスポーツ株式会社 ゴルフボール用樹脂組成物及びゴルフボール

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US5492972A (en) * 1990-12-10 1996-02-20 Acushnet Company Golf ball cover
JPH08155053A (ja) * 1994-12-08 1996-06-18 Sumitomo Rubber Ind Ltd ゴルフボール

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Publication number Priority date Publication date Assignee Title
US5492972A (en) * 1990-12-10 1996-02-20 Acushnet Company Golf ball cover
JPH08155053A (ja) * 1994-12-08 1996-06-18 Sumitomo Rubber Ind Ltd ゴルフボール

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6274669B1 (en) 1997-01-21 2001-08-14 Acushnet Company Golf ball cover compositions containing non-carboxylic acid polymeric compatibilizers
WO2000043449A1 (fr) * 1999-01-22 2000-07-27 Spalding Sports Worldwide, Inc. Balle de golf contenant un gel
GB2361436A (en) * 1999-01-22 2001-10-24 Spalding Sports Worldwide Inc Golf ball containing gel
GB2361436B (en) * 1999-01-22 2003-08-06 Spalding Sports Worldwide Inc Golf ball containing gel
EP1170038A2 (fr) * 2000-06-06 2002-01-09 Dunlop Slazenger Group Americas Inc Materiau pour le revêtement d'une balle de golf à forte elasticité
EP1170038A3 (fr) * 2000-06-06 2002-01-16 Dunlop Slazenger Group Americas Inc Materiau pour le revêtement d'une balle de golf à forte elasticité
US6896628B2 (en) 2000-06-06 2005-05-24 Dunlop Sports Golf ball cover material—high resilience
US8501871B2 (en) 2008-07-11 2013-08-06 Dunlop Sports Co., Ltd. Golf ball
US9040632B2 (en) 2008-07-11 2015-05-26 Dunlop Sports Co. Ltd. Golf ball
US8399563B2 (en) 2008-10-08 2013-03-19 Sri Sports Limited Golf ball
US8372915B2 (en) 2008-10-10 2013-02-12 Sri Sports Limited Golf ball
US20100167845A1 (en) * 2008-12-23 2010-07-01 Kim Hyun J Golf ball
US8809428B2 (en) * 2008-12-23 2014-08-19 Taylor Made Golf Company, Inc. Golf ball
US8399564B2 (en) 2008-12-26 2013-03-19 Sri Sports Limited Golf ball
US9517385B2 (en) 2008-12-26 2016-12-13 Dunlop Sports Co., Ltd. Golf ball and process for preparing the same
US9005050B2 (en) 2010-03-26 2015-04-14 Sri Sports Limited Golf ball
DE202010012480U1 (de) 2010-09-10 2011-12-12 M.A.C.'s Holding Gmbh Pinsel

Also Published As

Publication number Publication date
GB2343123A (en) 2000-05-03
JP2003504089A (ja) 2003-02-04
GB0004076D0 (en) 2000-04-12
AU8915898A (en) 1999-03-08

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