JPH10230023A - Golf ball - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a carry while assuring an adequate spin quantity by setting a golf ball weight at a specific range and setting the 10mm compression value of the ball and the shore D hardness of its cover at specific ranges. SOLUTION: This relatively lightweight golf ball is suitable for a golfer having a relatively low head speed of about 30m/sec in head speed and is formed by covering a core with the cover. The golf ball is so set that the weight thereof attains 39 to 45g, the 10mm compression value of the force necessary for compressively deforming the core by 10mm attains 1960 to 4410N and the Shore D hardness of the cover attains a range of 45 to <60 deg.. The ball diameter of the golf ball is set at >=41.67m in accordance with the specifications of the golf ball and the thickness of the cover is set at a range of 2.2 to 0.2mm. The cover is preferably formed of a compsn. formed by compounding an ionomer resin with a diene rubber. Butadiene rubber is used as the diene rubber.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a golf ball having a core covered with a cover, which is particularly suitable for golfers having a low head speed of about 30 m / sec.

[0002]

2. Description of the Related Art Conventionally, various golf balls have been proposed in which the flight distance is increased and the shot feeling (feeling) is improved. However, these golf balls are suitable for advanced golfers with high head speeds, and are not suitable for golf players with low head speeds such as beginners, ladies and senior players.

[0003] In the case of a golfer having a low head speed, a golf ball having a small compression value (soft) is suitable because the hitting force applied to the ball is small and the ball compression deformation speed is similarly low. In recent years, golf balls having a soft core have been proposed for golfers having a low head speed. However, when the core is softened, the use of a cover material of normal hardness for which resilience is sought reduces the spin rate of the golf ball, making it impossible to obtain an optimum golf ball lift. In addition, when the golf ball is light, if the core is soft and the cover is hard, the ball separates too quickly when hit, which is a problem in terms of feeling. On the other hand, if both the core and the cover are softened, the resilience of the golf ball is generally impaired due to insufficient hardness, and the flight distance is reduced.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to secure a proper spin amount (4500 rpm to 4800 rpm) to improve the flight distance and to set a proper ball 10 mm
It has a compression value (3500N to 4300N), so that it does not impair resilience, furthermore, suppresses the separation of the ball at the time of hitting and has a good feeling. It is lightweight for golfers with a low head speed of about 30m / sec. To provide a golf ball.

[0005]

According to the present invention, there is provided a golf ball having a core covered with a cover, the golf ball weighing 39 to 45 g, and the force (10 mm) required for compressing and deforming the core by 10 mm. Compression value)
And the cover has a Shore D hardness of 45 degrees to less than 60 degrees.

Although the compression value of the core and the Shore D hardness of the cover are reduced (softened) as described above, the weight of the golf ball is reduced to 39 to 45 g (R & A rule (R & A standard of the British Golf Association)). 2-15% lighter than the upper limit of 45.93 g), the above object can be achieved.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The golf ball of the present invention has a core covered with a cover. Golf ball weight 39-45
g. If the weight is less than 39 g, the trajectory is likely to change because the ball is too light to easily receive wind resistance during flight, and a sufficient flight distance cannot be obtained due to loss of inertia. Meanwhile, 4
If it exceeds 5 g, it is difficult to obtain an optimal lift of the golf ball, and therefore, a golfer with a low head speed will reduce the flight distance.

The 10 mm compression value of the core is 1
960N to 4410N. If it is less than 1960 N, the compression value is too low, and the hit feeling becomes too heavy. Further, the amount of deformation at the time of impact becomes too large, and there is a problem in terms of durability. On the other hand, if it exceeds 4410 N, the hit feeling becomes hard and the feeling becomes poor. In addition, the spin amount increases, and the trajectory of the ball becomes too high, such as so-called sloshing, which leads to a reduction in the flight distance.

The Shore D hardness of the cover is 45 to 60 degrees.
Less than degrees. If the Shore D hardness of the cover is less than 45 degrees, the cover becomes too soft, impairs the resilience and reduces the flight distance. If the Shore D hardness of the cover is 60 degrees or more, the cover becomes hard and the spin amount of the golf ball decreases. The golf ball diameter is 42.67 mm or more based on the standard of the golf ball, and is preferably 42.67 mm to +0.2 and -0.0 mm. The thickness of the cover is 2.2 mm to ± 0.2 mm.

[0010] The material of the core is not particularly limited, and ordinary materials may be used. For example, a composition in which a compounding agent such as zinc white is mixed with the base rubber may be used. The base rubber is, for example, natural rubber (NR), polyisoprene rubber (IR), styrene-butadiene copolymer rubber (SBR), or the like. The cover is preferably made of a composition obtained by blending an ionomer resin with a diene rubber.
Butadiene rubber may be used as the diene rubber,
Butadiene rubber having a cis-1,4 structure of 40% or more is preferred.

When butadiene rubber is blended with the ionomer resin, uncrosslinked butadiene rubber is added to the ionomer resin, and the mixture is kneaded at a temperature of 150 ° C. or more and less than 260 ° C. to thermally crosslink the butadiene rubber and to mix the butadiene rubber into the ionomer resin. What is necessary is just to disperse. Here, thermal crosslinking means that uncrosslinked butadiene rubber is crosslinked only by heat without using a crosslinking agent.

The ionomer resin has an ethylene-unsaturated carboxylic acid copolymer as a base resin,
For example, it can be obtained from an ethylene-unsaturated carboxylic acid copolymer and a metal compound capable of supplying a cation. Ethylene-
The unsaturated carboxylic acid-based copolymer is, for example, a copolymer of ethylene and an unsaturated carboxylic acid having 3 to 6 carbon atoms, such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, or vinyl benzoate. .

Metal compounds capable of supplying cations include, for example, formate, acetate, nitrate, carbonate, bicarbonate, oxide, hydroxide of alkali metals, alkaline earth metals, transition metals and the like. Alkoxide and the like. Examples of the type of metal include Na, Zn, Li, Mg, Mn, Ca, Co, and K. Examples of the ionomer resin include a metal salt of a copolymer of ethylene and methacrylic acid. Examples of commercially available ionomer resins include, for example, Himilan 1605, Himilan 1706, Himilan 1707, and Himilan AM731 manufactured by DuPont-Mitsui Polychemicals.
5, High Milan AM7317, High Milan AM7318
Etc.

[0014]

EXAMPLES Golf balls were produced by changing the weight (g) of the golf ball, the core compression (N), and the cover hardness (Shore D hardness) as shown in Table 1 (Inventions 1-4, Comparative Example 1). ~ 7). With respect to these golf balls, the spin rate, flight distance, and feeling were evaluated as follows. Table 1 shows the results.

Spin amount : When the spin amount is 4900 rpm or more, the trajectory becomes too high and the carry (carry) decreases. At 4000 rpm or less, the trajectory becomes too low, which also leads to a reduction in flight distance. This spin amount was measured by performing a strobe photograph of a ball hit at a head speed of 35 m / S by attaching # 1W (loft: 15 °) to a Miyama swing robot in an indoor lab test separately from actual hitting.

Flight distance (carry, run, flight tie
Beam): # 1W (the loft 15 °) is attached to the Miyamae swing robot manufactured by, was hit at a head speed of 35m / S,
The ball was actually hit and measured (outdoor experiment). Feeling : A golfer with a head speed of about 30 to 35 m / S tested a lightweight prototype ball and asked a questionnaire.
The feeling of the ball of about 0N to 4500N was good. However, if the ball weight is about 45.5g,
This compression value resulted in a slightly higher zone feeling better. In Table 1, “◎” represents extremely good, “○” represents good, “Δ” represents bad, and “×” represents extremely poor.

[0017]

[Table 1]

Note) Core 10 mm compression: The force required to compress and deform the core by 10 mm. Ball 10 mm compression: The force required to compress and deform the ball by 10 mm.

Ball initial speed: Measured by an initial speed tester specified in the R & A rule (ft / s). According to this rule, 250ft
/ s + 2% or less = 255 ft / s or less. Spin / launch angle: # 1W (loft 15 °) attached to a swing robot made by Miyamae, head speed 35m / S
And was measured (indoor test).

As apparent from Table 1, the inventions 1 to 4 have a proper spin amount (within the range of 4500 rpm to 4800 rpm) and a moderate ball compression of 10 mm (3500 N to 4300 N), and have a good flight distance and a high feel. The ring is excellent.

On the other hand, in Comparative Examples 1 to 7, since at least one of the ball weight, the core 10 mm compression and the cover hardness was out of the range of the present invention, the flight distance and the feeling were compared with those of the present invention 1 to 4. Inferior.

[0022]

As described above, the golf ball of the present invention has a golf ball weight of 39 to 45 g and a 10 mm compression value of the core of 1960 N to 4410 g.
Since the Shore D hardness of the cover is less than 45 degrees to 60 degrees in N, a proper spin amount is secured and the flight distance is improved, and since the ball has an appropriate amount of crushing, the resilience is not impaired. It is suitable for golfers with a low head speed of about 30 m / sec because the ball feels good while suppressing the ball separation at the time of hitting and is lightweight.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08L 9/00 C08L 9/00 21/00 21/00 23/26 23/26

Claims (4)

[Claims] 1. A golf ball comprising a core and a cover, wherein the weight of the golf ball is 39 to 45 g, and the force required for compressing and deforming the core by 10 mm (10 mm compression value) is 1960 N to 441.
A golf ball wherein the cover has a Shore D hardness of 45 to less than 60 at 0N. 2. A golf ball having a diameter of 42.67 mm-4.
2.87 mm, and the thickness of the cover is 1.8 mm
The golf ball according to claim 1, which has a thickness of about 2.4 mm. 3. The golf ball according to claim 1, wherein the cover is made of a composition obtained by blending an ionomer resin with a diene rubber. 4. The golf ball according to claim 3, wherein the diene rubber is butadiene rubber, and the butadiene rubber is dispersed in an ionomer resin and thermally crosslinked.