Golf ball and method for manufacturing same

Abstract

The present invention relates to a golf ball and a method for manufacturing same. The golf ball may include a first pole, a second pole, and a seam located between the first pole and the second pole, and a section structure including an outer surface having a plurality of dimples, a core, and a cover surrounding the core. In certain embodiments, the core includes 100 parts by weight of a butadiene rubber and 0.5 to 10 parts by weight of a polymer resin. The cover may include 100 parts by weight of an ionomer resin and 1 to 10 parts by weight of a butadiene rubber having a 1,2-bond content of 90% or more.

Claims

1. A golf ball comprising an outer surface having a plurality of dimples formed thereon, a core, and a cover surrounding the core, wherein the core comprises a composition comprising 100 parts by weight of a butadiene rubber and 0.5 to 10 parts by weight of a polymer resin, or 100 parts by weight of one or more selected from neutralized ionomers and commercial ionomers, and the cover comprises 100 parts by weight of an ionomer resin and 1 to 10 parts by weight of a butadiene rubber having a 1,2-bond content of 90% or more, wherein the golf ball is coated with at least one coating resin selected from the group consisting of one-component/two-component urethane resins, one-component/two-component acrylic urethane reins, and PVC resins, to a coating thickness in the range of 5 to 40 m and wherein the golf ball is coated with a top coating composition comprising 100 parts by weight of the coating resin and 1 to 3.5 parts by weight of a compound represented by the following formula 1: ##STR00002##

2. The golf ball of claim 1, wherein a difference in Shore D hardness (Cs-Cc), between an outermost surface (Cs) and a center (Cc) of the core is in the range of 8 to 15.

3. The golf ball of claim 1, wherein the polymer resin is one or more selected from the group of consisting of PET(polyethylene terephthalate), PP(polypropylene), PE(polyethylene), PVC(polyvinyl chloride), EVA(ethylene vinyl acetate) and nylon.

4. The golf ball of claim 1, wherein the core has a compression in the range of 40 to 70 PGA.

5. The golf ball of claim 1, wherein the core has a diameter in the range of 38.0 to 41.0 mm.

6. The golf ball of claim 1, wherein the ionomer resin is one or more selected from the group consisting of a hard ionomer which is a magnesium, lithium, sodium or zinc salt of a copolymer of a C.sub.2-C.sub.8 olefin with a C.sub.3-C.sub.8 unsaturated monocarboxylic acid and has a modulus of 30,000 to 55,000 P.S.I., and a soft ionomer which is a magnesium, lithium, sodium or zinc salt of a copolymer of a C.sub.2-C.sub.8 olefin with a C.sub.2-C.sub.22 acrylate ester-based unsaturated monomer and has a modulus of 3,000 to 7,000 P.S.I.

7. The golf ball of claim 1, wherein the ionomer resin is one or more selected from the group consisting of a hard ionomer which is a magnesium, lithium, sodium or zinc salt of a copolymer of ethylene with methacrylic acid, and a soft ionomer which is a sodium salt of a terpolymer of n-butyl or iso-butyl acrylate, ethylene and methacrylic acid.

8. The golf ball of claim 1, wherein the coating resin comprises 1 to 10 parts by weight of at least one pigment selected from the group consisting of titanium dioxide, barium sulfide, zinc oxide and zinc sulfide, based on 100 parts by weight of the coating resin.

Description

MODE FOR INVENTION

(1) Hereinafter, preferred examples will be presented for a better understanding of the present invention. It is to be understood, however, that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention.

(2) The components used in the following examples and comparative examples are as follows.

(3) 1) Core of the golf ball: 100 parts by weight of butadiene rubber (trade name BR1208)+1.5 parts by weight of EVA;

(4) 2) Resin for cover of the golf ball: 95 parts by weight of ionomer (including trade name Surlyn series 8940, 9910, 8660 and 9320, manufactured by DuPont)+5 parts by weight of trade name RB810 (butadiene rubber having a 1,2 bond content of 90% or more);

(5) 3) Core additives: ZDA (zinc diacrylate curing agent), ZnSt (zinc stearate; lubricant), DCP (dicumyl peroxide; crosslinking agent), and antioxidant.

EXAMPLES 1 AND 2

(6) From the above components, a golf ball having a core, a cover and dimples was manufactured according to the mixing ratio shown in below Table 1.

(7) TABLE-US-00001 TABLE 1 Number of Core Cover dimples Example 1 100 parts by weight of BR1208 + Surlyn ionomer 312 25 parts by weight of ZDA + (65 parts by weight of 8940 + 25 parts by weight of ZnO + 30 parts by weight of 9910) + 5 pasts by weight of ZnSt + 5 parts by weight of RB810) + 1.0 part by weight of DCP + 3 parts by weight of TiO.sub.2 0.5 parts by weight of antioxidant + 5.0 parts by weight of EVA Example 2 100 parts by weight of BR1208 + Surlyn ionomer 312 30 parts by weight of ZDA + (65 parts by weight of 8940 + 25 parts by weight of ZnO + 30 parts by weight of 9910 + 5 parts by weight of ZnSt + 5 parts by weight of RB810) + 1.0 part by weight of DCP + 3 parts by weight of TiO.sub.2 0.5 parts by weight of antioxidant + 5.0 parts by weight of EVA

(8) The properties regarding the cores were measured, and the results of the measurement are shown in below Table 2.

(9) The properties were measured in the following manner.

(10) Size (mm): The distance between the first pole and the second pole, and two types of seams, were measured, and then the measurements were averaged.

(11) Compressive strength (COMP, unit: PGA) : When a test sample was compressed to 2.5 mm, a pressure measured by a compression sensor located under the pressing location of the ball was read. The unit is generally kgf/cm.sup.2.

(12) Shore D hardness: Shore D hardness was measured in accordance with ASTM D2240. In addition, JIS-C hardness as Japan measurement method was also measured.

(13) TABLE-US-00002 TABLE 2 Hardness Diameter COMP Weight Center Surface mm PGA g (Cc) (Cs) Cs-Cc Example 39.90 44.6 38.36 Shore D 30.9 43.0 12.1 1 JIS-C 53.8 72.6 18.8 Example 39.90 50.5 38.43 Shore-D 32.9 45.3 12.4 2 JIS-C 54.0 75.1 21.1

(14) As can be seen in the above Table 2, the cores manufactured in Examples 1 and 2 had a size in the range of 38.0 to 41.0 mm, a compressive strength (COMP) in the range of 40 to 70 PGA, and the difference in Shore D hardness, (Cs-Cc) between the outermost surface (Cs) and center (Cc) of the core, in the range of 8 to 15.

(15) Next, a cover material was once injection-molded around the core to form a one-layer cover, and then the seam of the cover was grinded, Thereby preparing a two-piece golf ball.

(16) The two-piece golf ball was coated with a one-component water-soluble TPU (thermoplastic urethane) primer paint by air spray, and then irradiated with near infrared (NIR) light, after which it was coated with a two-component solvent type TPU (thermoplastic urethane) clear paint, thereby manufacturing a golf ball comprising a coating layer having a thickness of about 20 m.

(17) The properties of the golf balls were measured in the same manner as described in the above Table 2, and the results of the measurement are shown in below Table 3. For reference, the coefficient of restitution (C.O.R) was calculated as the ratio from the flight velocity and the rebound speed, when the golf ball was collided against a wall at a distance of 1 m at a velocity of 90 mph.

(18) TABLE-US-00003 TABLE 3 Coefficient Hard- Hard- of Size COMP Weight ness ness restitution mm PGA g Shore D JIS-C (C.O.R.) Example 1 42.83 59.3 45.49 65.3 95.0 0.8068 Example 2 42.81 61.2 45.65 60.5 91.7 0.8001

(19) As can be seen in the above Table 3, the golf balls finally manufactured in Examples 1 and 2 had a size in the range of 41 to 44 mm, a compressive strength (COMP) in the range of 5 to 62 PGA, and a coefficient of restitution (C.O.R) of 0.8000 or more.

COMPARATIVE EXAMPLES 1 TO 4

(20) Four different commercial golf balls were prepared, and the properties of the golf balls were measured in the same manner as described in the above Table 3. The results of the measurement are shown in below Table 4.

(21) For reference, Titleist ProV1, Srixon Q-STAR (2-piece), Bridgestone ALTUS (2-piece) and Callaway HEX Diablo golf balls were used as Comparative Examples 1 to 4, respectively.

(22) TABLE-US-00004 TABLE 4 Coefficient of Size COMP Weight Hardness restitution mm PGA g Shore D (C.O.R.) Comparative 42.71 96.3 45.62 57 0.7989 Example 1 Comparative 42.72 87.6 45.60 62 0.7844 Example 2 Comparative 42.68 75.0 45.50 63 0.7868 Example 3 Comparative 42.83 70.0 45.38 64 0.7898 Example 4

(23) As can be seen in the above Table 4, the golf balls of Comparative Examples 1 to 4 had a compressive strength of 70 PGA, which was higher than those of Examples 1 to 2 (ranging from 55 to 62 PGA), and a coefficient of restitution (C.O.R) in the range of 0.7868 to 0.7989, which was lower than those of Examples 1 to 2 (ranging from 0.8000 or more).

TEST EXAMPLE

(24) Tests regarding the flight distance of each golf balls in Examples 1 and 2 and Comparative Examples 1 to 4 were performed, and the results of the tests are summarized in below Table 5.

(25) TABLE-US-00005 TABLE 5 Club Ball Spin Flight speed speed rate Height Flight time Total mph mph rpm yards yards sec yards Example 1 93.2 139.6 2375.1 32.5 211.3 6.4 225.6 Example 2 93.2 139.4 2446.6 31.3 211.7 6.4 225.8 Comparative 93.2 139.5 2863.8 33.8 212.7 6.7 223.0 Example 1 Comparative 93.2 139.3 2679.0 32.1 211.5 6.6 224.4 Example 2 Comparative 93.2 139.9 2829.4 32.0 211.3 6.6 224.4 Example 3 Comparative 93.2 139.7 2618.0 31.8 211.6 6.5 225.0 Example 4

(26) As can be seen in the above Table 5, the golf balls of Examples 1 and 2 were much superior to the commercial golf balls of Comparative Examples 1 to 4 in terms of the spin rate (advantageous for a long flight distance with lower back spin in driver shot) among the test items measured under similar club speed and ball speed conditions. In addition, it could be seen that the golf balls of Examples 1 and 2 were suitable in terms of height, landing angle and flight time, and excellent in terms of total distance of flight distance plus roll distance.