Classifications

• • A—HUMAN NECESSITIES
  • A63—SPORTS; GAMES; AMUSEMENTS
  • A63B—APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT
  • A63B43/00—Balls with special arrangements
  • A63B43/008—Balls with special arrangements with means for improving visibility, e.g. special markings or colours
• • A—HUMAN NECESSITIES
  • A63—SPORTS; GAMES; AMUSEMENTS
  • A63B—APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT
  • A63B37/00—Solid balls; Rigid hollow balls; Marbles
  • A63B37/0003—Golf balls
• • A—HUMAN NECESSITIES
  • A63—SPORTS; GAMES; AMUSEMENTS
  • A63B—APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT
  • A63B37/00—Solid balls; Rigid hollow balls; Marbles
  • A63B37/0003—Golf balls
  • A63B37/0023—Covers
  • A63B37/0024—Materials other than ionomers or polyurethane
• • A—HUMAN NECESSITIES
  • A63—SPORTS; GAMES; AMUSEMENTS
  • A63B—APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT
  • A63B37/00—Solid balls; Rigid hollow balls; Marbles
  • A63B37/0003—Golf balls
  • A63B37/005—Cores
  • A63B37/0051—Materials other than polybutadienes; Constructional details

Definitions

• This invention relates generally to golf balls. More particularly, the invention relates to a golf ball which is suitable for use in night golf and for use at indoor golf ranges and golf practice ranges.
• JP-Y 3015308 describes a golf ball in which a phosphorescent paint has been applied to the surface of the ball cover.
• JP-A H04-122372 teaches art in which a luminous paint is applied to the skin of a golf ball.
• Luminous paints mentioned in this art include phosphorescent substances such as acrylics that collect sunlight or light from fluorescent lamps and luminesce when the surroundings darken.
• the golf balls in the foregoing art all use phosphorescent paint or luminous paint on the surface of the golf ball, that is, as a paint film, and so this art requires the formation of a thicker paint film than in the past. Hence, there is a concern that problems such as crazing of the paint film or a decrease in the distance of the ball may arise.
• JP-A S61-176369 discloses a golf ball for use in night golf that has a surface layer containing specific amounts of phosphorescent pigment and glass beads with respect to the base resin. Mention is made here of the use of, for example, ZnS—Cu as the phosphorescent pigment.
• JP-A 2003-339915 teaches art wherein a paint containing a mechanoluminescent material which emits light upon receiving mechanical energy at the time of ball impact is applied to the outer skin of a golf ball.
• a paint film is formed using paint that contains a large amount of mechanoluminescent material, and one concern is that the paint film may become brittle, allowing scuff marks to readily form on the ball upon impact.
• a golf ball having a core and a cover of a single layer or a plurality of layers that encases the core by forming the core or at least one layer of the cover of a resin composition which includes from 5 to 200 parts by weight of a mechanoluminescent material per 100 parts by weight of a rubber material or resin material serving as the base material, the ball has an excellent visibility in that, even under dark conditions, the ball impact site can be clearly confirmed visually at the time of impact, and the ball moreover is able to maintain a good scuff resistance. Furthermore, at indoor and practice ranges, golf balls are often repeatedly used.
• the invention provides a golf ball having a core and a cover of one or a plurality of layers that encases the core, wherein the core or at least one layer of the cover is formed of a resin composition which contains from 5 to 250 parts by weight of a mechanoluminescent material that receives mechanical energy and luminesces per 100 parts by weight of a base material which is a rubber material or a resin material.
• the mechanoluminescent material is preferably made of strontium aluminate crystals doped with primarily at least one type of rare-earth ion.
• the mechanoluminescent material-containing resin material is preferably an ionomer resin.
• an outermost layer of the cover is formed of a mechanoluminescent material-containing resin composition, the content of the mechanoluminescent material being from 15 to 100 parts by weight per 100 to parts by weight of the resin material.
• the cover has a plurality of layers, and an inner cover layer adjoining an outermost layer of the cover is formed of a mechanoluminescent material-containing resin composition.
• the content of the mechanoluminescent material included in the inner cover layer is preferably from 20 to 250 parts by weight per 100 parts by weight of the resin material.
• the golf ball of the invention by including a special mechanoluminescent material in the core or at least one layer of the cover, enables the ball impact site to be clearly confirmed visually at the time of impact--even under dark conditions, and moreover enables the ball to obtain an excellent scuff resistance.
• the golf ball of the invention has a core and a cover of one or a plurality of layers that encases the core.
• Various types of cores such as a solid core or a wound core, may be used as the golf ball core in this invention.
• the core When the core is a solid core, it can be formed using a known rubber composition.
• the base rubber is exemplified by polybutadiene, with the use of cis-1,4-polybutadiene having a cis structure content of at least 40% as the chief component being recommended in particular, in addition, natural rubber, polyisoprene rubber, styrene-butadiene rubber or the like may also be included within this base rubber.
• the metal salts or ester compounds of unsaturated fatty acids may be included as co-crosslinking agents in the rubber composition.
• Such metal salts are exemplified by the zinc salts, magnesium salts, and calcium salts, and such ester compounds are exemplified by trimethylolpropane trimethacrylate.
• the content of these co-crosslinking agents per 100 parts by weight of the base rubber is generally at least 10 parts by weight, and preferably at least 15 parts by weight, with the upper limit being 50 parts by weight or less, and preferably 40 parts by weight or less.
• An organic peroxide may be included in the rubber composition.
• Illustrative examples include 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, dicumyl peroxide, di(t-butylperoxy)-m-diisopropylbenzene and 2,5-dimethyl-2,5-di-t-butylperoxyhexane.
• Illustrative examples of such commercial products include Percumyl D (NOF Corporation) and Perhexa 3M-40 (NOF Corporation).
• the content of these organic peroxides per 100 parts by weight of the base rubber is generally at least 0.1 part by weight, and preferably at least 0.5 part by weight, with the upper limit being 5 parts by weight or less, and preferably 2 parts by weight or less.
• additives such as sulfur, antioxidants, zinc oxide, barium sulfate, organosulfur compounds such as the zinc salt of pentachlorothiophenol, and zinc stearate may be included.
• sulfur, antioxidants, zinc oxide, barium sulfate, organosulfur compounds such as the zinc salt of pentachlorothiophenol, and zinc stearate may be included.
• the contents of these additives are suitably adjusted in accordance with various purposes, and are not particularly limited.
• the diameter of the core is suitably selected according to the intended ball construction, and is not particularly limited.
• the core diameter is preferably at least 32.0 mm, and more preferably at least 33.0 mm, with the upper limit being preferably 40.5 mm or less, and more preferably 39.5 mm or less.
• the core has a deflection (mm) when compressed under a final load of 1,275 N from an initial load of 98 N which, although not particularly limited, is preferably from 2.0 to 5.0 mm, more preferably from 2.2 to 4.5 mm, and even more preferably from 2.4 to 4.0 mm.
• this value is too small, that is, when the core is too hard, the feel of the ball when struck with a driver may be hard and the contact time between the club and the ball may be too short, resulting in poor controllability.
• the deflection (deformation) is too large, the feel of the ball when struck with a driver may be too soft, or the durability of the ball to cracking on repeated impact may worsen.
• the core may be produced by a known method.
• a method in which the composition is intensively mixed using a conventional mixing apparatus such as a Banbury mixer, kneader or roll mill
• the resulting compound is compression molded in a core mold.
• a wound core may be obtained by a commonly used method that is known to the art.
• the cover encasing the core may be composed of a single layer or a plurality of layers.
• a thermoplastic resin or a thermoset resin may be used as the base material for each layer of the cover, with the use of a thermoplastic resin or a thermoplastic elastomer being especially preferred.
• thermoplastic resins include ionomer resins. Commercial products that may be used include those of the trade names Himilan (from DuPont-Mitsui Polychemicals Co., Ltd.), Surlyn (E.I. DuPont de Nemours and Co.) and Iotek (Exxon).
• thermoplastic elastomers examples include polyester, polyamide, polyurethane, olefin and styrene-based thermoplastic elastomers.
• Commercial products that may be used include those of the trade names Hytrel (from DuPont-Toray Co., Ltd.), Pelprene (Toyobo Co., Ltd.), Pebax (Toray Industries, Inc.), Pandex (DIC Covestro Polymer Ltd.), Santoprene (Monsanto Chemical Co.), Tuftec(Asap Chemical Industry Co., Ltd.) and Dynaron (JSR Corporation).
• An ionomer resin or a thermoplastic polyurethane elastomer is preferably used as the thermoplastic resin or thermoplastic elastomer.
• the core or at least one layer of the cover contains a mechanoluminescent material that receives mechanical energy and luminesces.
• mechanoluminescent materials are either mechanoluminescent materials obtained by doping an inorganic matrix material with luminescent centers consisting of at least one type of rare-earth or transition metal that emits light when electrons excited by mechanical energy return to the ground state, or mechanoluminescent materials having lattice detects that emit light when electrons excited by mechanical energy return to the ground state.
• these inorganic matrix materials include oxides, sulfides, carbides and. nitrides having a melilite structure, an FeS 2 structure, a wurtzite structure, a spinet structure, a corundum structure or a ⁇ -alumina structure.
• the luminescent centers doped in the inorganic matrix material are preferably of one or more type from among rare-earth ions such as Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dv, Ho, Er, Tm, Yb and Lu, and transition metal ions such as Ti, Zr, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Nb, Mo, Ta and W.
• rare-earth ions such as Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dv, Ho, Er, Tm, Yb and Lu
• transition metal ions such as Ti, Zr, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Nb, Mo, Ta and W.
• the mechanoluminescent material used in this invention is preferably a material obtained by doping crystals of strontium aluminate (SAO), which is a double oxide of aluminum and strontium, with primarily rare-earth ions, and preferably europium (Eu) ions.
• SAO strontium aluminate
• the mechanoluminescent material used in this invention is generally in the form of a powder.
• the powder has a primary particle size, as measured by the laser diffraction/scattering method, of preferably from 1 to 5 ⁇ m, and more preferably from 2 to 3 ⁇ m.
• a primary particle size as measured by the laser diffraction/scattering method, of preferably from 1 to 5 ⁇ m, and more preferably from 2 to 3 ⁇ m.
• the particle size is too large, strong luminescence is obtained, but the durability and scuff resistance of the ball may worsen.
• the particle size is too small, the luminescence may weaken.
• the core or cover which includes this mechanoluminescent material have a material hardness, expressed in terms of Shore D hardness, which is preferably at least 35, more preferably at least 40, and even more preferably at least 45.
• the upper limit is preferably 90 or less, more preferably 85 or less, and even more preferably 80 or less.
• the viscoelasticity (tan ⁇ ) of the core or cover material containing the mechanoluminescent material is preferably 0.5 or less, more preferably 0.4 or less, and even more preferably 0.3 or less. When this is too large, the rebound may be low and a good distance may not be obtained.
• This viscoelasticity is defined as the ratio between storage modulus and loss modulus in dynamic viscoelasticity measurement at a temperature of 23° C., an oscillation frequency of 15 Hz and 1.0% strain.
• the content of mechanoluminescent material used in this invention is set to from 5 to 250 parts by weight, and preferably from 10 to 200 parts by weight, per 100 parts by weight of the base rubber or base resin in the core or at least one layer of the cover.
• this content is low, a ball impact site luminescing effect is not sufficiently obtained.
• this content is high, the durability and scuff resistance of the ball worsen.
• the content of the mechanoluminescent material is preferably from 15 to 100 parts by weight per 100 parts by weight of the resin material in the outermost layer.
• the mechanoluminescent material may be included in an inner cover layer adjoining an outermost layer of the cover.
• adjusting the content of mechanoluminescent material within the range to preferably 20 to 250 parts by weight, and more preferably 40 to 200 parts by weight, per 100 parts by weight of the resin material in the inner cover layer, that is, so as to be higher than when the mechanoluminescent material is included in the outermost layer, is desirable from the standpoint of the luminescing effect and visibility under dark conditions.
• the resin composition of the outermost layer has a percent haze of preferably 80 or less, and more preferably 70 or less.
• percent haze is the value computed as shown below from total light transmittance and diffuse transmittance. Reference may be made to JIS K7136 (2000) for details.
• the total light transmittance and diffuse transmittance mentioned above refer to the light transmission ratio and diffusion ratio when light from a light source is made to pass through a test specimen of plastic (resin composition for outermost layer), and are values in conformity with JIS K7105 (1981).
• a transparent or translucent resin material as the resin material for satisfying the above percent haze value.
• the above-mentioned base resins such as ionomer resins, polyurethane elastomers, polyester elastomers, polyamide elastomers and polyolefin elastomers.
• various elastomers and additives, effect pigments, colorants and the like may be added to these resin materials within ranges that do not detract from the transparency.
• additives such as UV absorbers, antioxidants, metallic soaps, and pigments and inorganic tillers other than those mentioned above may be suitably included in the base resins for the respective layers of the cover, provided that these are included in to suitable amounts within ranges that do not detract from the objects and advantageous effects of the invention.
• the thicknesses of the individual cover layers are not particularly limited, although it is desirable for these layers to be formed to a thickness of preferably at least 0.3 mm, more preferably at least 0.5 mm, and even more preferably at least 0.7 mm, with the upper limit being preferably 3.0 mm or less, more preferably 2.7 mm or less, and even more preferably 2.4 mm or less.
• the individual cover layers are too thin, durability to cracking under repeated impact may worsen. On the other hand, when the individual cover layers are too thick, the feel of the ball at impact may worsen.
• the thickness of the inner cover layer may be set in the same range as described above, but it is desirable for the thickness of the outermost layer of the cover to have an upper limit of preferably 1.5 mm or less, and more preferably 1.2 mm or less.
• a known method such as injection molding or compression molding may be used to obtain a golf ball in which the above cover encases the core.
• the golf ball when injection molding is carried out, the golf ball may be produced by setting a prefabricated solid core within a mold and, in the usual manner, introducing a cover material into the mold.
• a three-piece solid golf ball having a core and a cover of two layers can be produced by carrying out this injection molding process twice, once for each layer of the cover.
• a mold having numerous dimple-forming projections formed in the cavity thereof.
• the golf ball may be rendered into a finished product by carrying out painting and the like in accordance with ordinary known methods.
• the paint used is not particularly limited, and may be a clear coating that helps the cover luminesce effectively, or may include an effect pigment such as a pearlescent pigment.
• the thickness of the golf ball paint film is preferably within a range of 5 to 25 ⁇ m.
• the golf ball of the invention have a deflection (deformation) when compressed under a final load of 1.275 N (130 kg) from an initial load of 98 N (10 kgf) which is generally at least 2.0 mm, preferably at least 2.3 mm, and more preferably at least 2.5 mm, with the upper limit being typically 5.0 mm or less, preferably to 4.0 mm or less, and more preferably 3.7 mm or less.
• the ball deflection is smaller than this range, the feel of the ball at impact may be hard and the contact time between the ball and the club at the time of impact may be too short, resulting in poor controllability.
• the ball deflection is larger than this range, the feel may be too soft and the durability to cracking on repeated impact may worsen.
• the golf ball of the invention can be made to conform with the Rules of Golf.
• the ball may be formed to a diameter of not less than 42.67 nun and a weight of not more than 45.93 g.
• the upper limit in the diameter is preferably 44.0 mm or less, more preferably 43.5 mm or less, and most preferably 43.0 mm or less.
• the lower limit in the weight is preferably 44.5 g or more, more preferably 45.0 g or more, even more preferably 45.1 g or more, and still more preferably 45.2 g or more.
• Solid cores were produced by using the rubber composition shown in Table 1 below, which composition was common to all the Examples, and vulcanizing for 15 minutes at 155° C.
• cover materials formulated as shown in Table 2 below were mixed in a kneading-type twin-screw extruder, giving pelletized cover materials, following which these cover materials were injected into a mold in which the solid core had been placed, thereby producing two-piece solid golf balls.
• cover materials for the inner cover layer and the outer cover layer were successively injection-molded over the core, thus producing a three-piece solid golf ball. Dimples common to all the Examples were formed on the surface of the cover at this time.
• the cover material (resin composition) was molded into a sheet having a thickness of 2 mm and left to stand for at least two weeks, following which the Shore D hardness was measured in accordance with ASTM D2240-95.
• the surfaces of the golf balls obtained above were coated to a thickness of 16 ⁇ m with the coating compositions in Table 3 below, thereby producing golf balls as finished products.
• the ball diameter, deflection, luminescent state and scuff resistance for each of the golf balls obtained above were measured or evaluated by the following methods. The results are shown in Table 4.
• the diameters at five random dimple-free areas on the surface of a ball were measured at a temperature of 23.9+1° C. and, using the average of these measurements as the measured value for a single ball, the average diameter for five measured balls was determined.
• the golf balls were held isothermally at 23° C. and five balls of each type were hit at a head speed of 33 m/s using as the club a pitching wedge mounted on a swing robot machine.
• the damage to the ball from the impact was visually rated based on the following 5-point scale, and the average score was calculated for each type of ball.

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• Health & Medical Sciences (AREA)
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• Physical Education & Sports Medicine (AREA)
• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Compositions Of Macromolecular Compounds (AREA)

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Citations (5)

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• 2016
  • 2016-06-22 JP JP2016123266A patent/JP6790491B2/ja active Active
• 2017
  • 2017-05-25 US US15/605,058 patent/US20170368426A1/en not_active Abandoned

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