JP3107766B2 - Golf ball - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a golf ball, and more particularly to a golf ball having high resilience performance and a long flight distance.
The present invention also relates to a golf ball that has good flyer resistance and hardly generates flyer even when shot from a rough.

[0002]

2. Description of the Related Art Conventionally, as a round golf ball, a solid golf ball in which a solid core made of a vulcanized molded body of a rubber composition mainly composed of polybutadiene is covered with a cover, a rubber-based or liquid-based center is used. Covers the wound core formed by winding thread rubber around
Although the wound golf ball covered with has been frequently used, the ball often penetrates into a deep lawn during play regardless of the type of the ball.

[0003] In the shot from the deep grass, a phenomenon called a flyer occurs in which the backspin amount is reduced and the ball rises high because the grass is bitten between the club face and the ball, and a phenomenon called a flyer occurs. It was one of the causes that impaired controllability.

This flyer is a solid golf ball,
Although it occurs in any of the thread-wound golf balls, the easiness of the occurrence is examined for each cover. As a result, the ionomer-based cover is likely to cause a flyer, and the balata-based cover is unlikely to cause a flyer. However, this balata-based cover has a problem that its resilience performance is lower than that of an ionomer-based cover. For example, the restitution coefficient of a two-piece solid golf ball using an ionomer type cover is generally 6
However, the coefficient of restitution of a thread-wound golf ball using a balata-based cover is generally as low as 40 to 45, so that a thread-wound golf ball using a balata-based cover is a two-piece solid golf ball using an ionomer-based cover. There is a problem that the flight distance is inferior to that of.

[0005]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems in the prior art, and provides a golf ball having high resilience performance, a long flight distance, good flyer resistance, and less occurrence of flyer. The purpose is to provide.

[0006]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have found that
The base polymer of the cover is polystyrene in the base polymer.
Phase at both terminal phases, the polybutadiene phase
Block with lysoprene or polyolefin phase
Styrene-based thermoplastic elastomer composed of copolymer
30% by weight or more, and the cover has a complex elastic modulus at −10 ° C. at 5% dynamic strain of 5% in a dynamic viscoelasticity temperature dispersion curve at a frequency of 10 Hz measured at a heating rate of 4 ° C./min.
When made of a material of 0 to 1500 kgf / cm ^{2 and} having a rebound resilience of 50% or more by a trypsometer,
They have found that the above problems can be solved, and have completed the present invention.

[0007] To explain this in detail, the present inventors,
First, in order to pursue the cause of flyer generation during golf round play and to prevent flyer generation, the dynamic hardness of the cover material measured using a specific cover material and a specific amount of dynamic strain was used. , that is, it was found that the complex elastic modulus is required to Rukoto within a specific range. That is, using a specific cover material, the complex elastic modulus at −10 ° C. at a dynamic strain of 5% is 50 in a dynamic viscoelasticity temperature dispersion curve at a frequency of 10 Hz measured at a temperature rising rate of the cover material of 4 ° C./min. ~1500kgf / cm ² of to Rutoki in range, it is possible to suppress the flyer from occurring,
Further, in order to retain the necessary resilience performance as golf balls, the complex elastic modulus 50 kgf / cm ² or more to maintain its single and <br/> both the impact resilience by tripling source meter 50%
It found that need to be there.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As described above, the cover has a temperature rising rate of 4 ° C. /
In the dynamic viscoelasticity temperature dispersion curve at a frequency of 10 Hz measured in minutes, it is necessary that the complex elastic modulus at −10 ° C. at a dynamic strain of 5% is 50 to 1500 kgf / cm ² . The complex elastic modulus of the cover under the above conditions is 1500 kg
When f / cm ² is exceeded, the complex elastic modulus of the cover of the conventional golf ball does not change, and it is no longer possible to prevent the occurrence of a flyer. The elastic modulus is preferably 1200 kgf / cm ² or less under the above conditions,
910 kgf / cm ² or less is more preferable, and 640 kgf / cm ² or less.
f / cm ² or less is more preferable. When the complex elastic modulus under the above conditions is smaller than 50 kgf / cm ² ,
Since the resilience performance is lowered distance decreases, complex elastic modulus of the cover is preferably 65 kgf / cm ² or more under the above conditions, 165kgf / cm ² or more is more preferable.

The complex elastic modulus in the present invention is a complex elastic modulus at −10 ° C. when measured in a tensile mode at a temperature rising rate of 4 ° C./min, a frequency of 10 Hz, and a dynamic strain of 5% using a viscoelastic spectrometer. And the following formula (I)
More required.

[0010]

(Equation 1)

[0011] The fact that there is a correlation between the case where a golf ball hits a high frequency at room temperature and the complex elastic modulus measured at a low temperature of 10 Hz with a viscoelastic spectrometer at the time of hitting is a temperature-frequency conversion rule. Can be derived from

In the present invention, by setting this and the amount of dynamic strain to 5%, which is close to the actual approach shot, the complex elastic modulus at −10 ° C. measured at 5% dynamic strain correlates with the occurrence of flyer. It is clear that there is.

Phenomenologically, if the complex elastic modulus of the cover is reduced, the cover can follow the club face and be deformed at the time of an approach shot, and the spin amount increases, so that the distance between the ball and the club face becomes large. It is thought that the necessary spin amount will be secured even if the turf is caught in the turf.

It is necessary that the cover has a rebound resilience by a trypsometer of 50% or more. When the rebound resilience is less than 50%, a large amount of spin is applied and a flyer is unlikely to occur, but the resilience performance is reduced and a flight distance is not obtained. The rebound resilience by this trypsometer needs to be 50% or more as described above.
In order to further improve the flight distance, the rebound resilience is preferably at least 65%, more preferably at least 70%. However, if the rebound resilience is too large, a flyer is likely to occur even if the complex modulus is 1500 kgf / cm ^2. Therefore, the rebound resilience is preferably 90% or less, and more preferably 85% or less.

Here, the complex elastic modulus of the conventional ionomer-based cover and balata-based cover and the coefficient of restitution of the two-piece solid golf ball using the ionomer-based cover and the thread-wound golf ball using the balata-based cover are as follows. As shown in Table 1.

[0016]

[Table 1]

To obtain a golf ball having a long flight distance,
As described above, in order to have the same high resilience performance as an ionomer-based cover with a large coefficient of restitution, and to improve fryer resistance and prevent the occurrence of fryer, it is necessary to lower the complex elastic modulus than the ionomer-based cover There is.

For this purpose, it is preferable to use a thermoplastic elastomer comprising a hard segment (hard phase) and a soft segment (soft phase). In particular, a styrene-based thermoplastic elastomer is most suitable.
In the light, styrene-based thermoplastic elastomers
Use a thermoplastic elastomer. This styrene- based thermoplastic elastomer has properties closest to vulcanized rubber among thermoplastic elastomers, has a low complex elastic modulus, and has the best fryer resistance.

The styrene-based thermoplastic elastomer is preferably contained in the base polymer of the cover (ie, the polymer constituting the base constituting the cover) in an amount of 30% by weight or more, and the fryer resistance is more reliably improved. In order to achieve this, the styrene-based thermoplastic elastomer preferably contains at least 50% by weight, more preferably at least 60% by weight, and further preferably at least 70% by weight.
That is, 100% by weight may be a styrene-based thermoplastic elastomer.

When this styrene-based thermoplastic elastomer is used in combination with another resin, an ionomer is preferred as the resin because of its high resilience performance. Examples of the ionomer include α-olefin and α,
Metal ion neutralized product of a binary copolymer with β-unsaturated carboxylic acid, terpolymer of α-olefin with α, β-unsaturated carboxylic acid and α, β-unsaturated carboxylic acid ester Various materials such as a metal ion neutralized product or a mixture thereof can be used, but in order to obtain high resilience performance, a binary copolymer of an α-olefin and an α, β-unsaturated carboxylic acid is used. Metal ion neutralizers are suitable. When commercially available products of these ionomers are exemplified by trade names, for example, "Himilan" manufactured by Mitsui Dupont Polychemicals Co., Ltd., "Surlyn" manufactured by DuPont, "Iotech" manufactured by Exxon Chemical Co. Several products with different part numbers are commercially available.

[0021] described in detail for the above styrene-based thermoplastic elastomer, structure of the styrene-based thermoplastic elastomer is composed of a hard segment and a soft segment, soft segment expressing a styrenic thermoplastic elastomer unique elastomeric properties, In the forming process, the hard segment is melted and plasticized to exhibit the forming processability, and is hardened when the forming is completed, thereby exhibiting a function as a constraint component for preventing plastic deformation.

The styrene-based thermoplastic elastomer of this is
SBS is a block copolymer having polystyrene in the hard segment and polybutadiene, polyisoprene or polyolefin in the soft segment, having a polystyrene phase (S) at both terminal phases and a polybutadiene phase (B) in the intermediate phase. A phase having a polyisoprene phase (I) as an intermediate phase and a polyolefin phase (ethylene / butylene = EB) having a polystyrene phase (S) at both terminal phases and having a polyisoprene phase (I) as an intermediate phase. Or ethylene / propylene = EP) is SEBS or SEPS. The above SEBS is SB
S and SEPS correspond to those obtained by saturating SIS by hydrogenation to eliminate double bonds. These SBS, SI
Preferable specific examples of S, SEBS, SEPS and the like are given by their trade names. As a commercial product of SBS, for example, there is a “TR” series manufactured by Nippon Synthetic Rubber Co., Ltd.
Are commercially available products such as "SIS" series manufactured by Nippon Synthetic Rubber Co., Ltd., and commercially available SEBS products are "ToughTech" series manufactured by Asahi Kasei Kogyo Co., Ltd. For example, there is a "Septon" series manufactured by Kuraray Co., Ltd.

[0023]

In the cover used in the present invention, various additives such as pigments, dispersants, antioxidants, ultraviolet absorbers, light stabilizers and the like may be added, if necessary, in addition to the base polymer. Can be. The method for coating the cover on the core is not particularly limited. For example, a half-shell having a hemispherical shell shape is formed from the cover composition,
The method may be such that the core is covered by using a plurality of sheets and heat-molded under pressure, or a method of directly injection-molding the cover composition on the core. Although the thickness of the cover is not particularly limited, a thickness of about 0.8 to 3.5 mm is usually suitable.

The core may be a solid core or a wound core. The solid core may have not only a one-layer structure but also a two-layer structure or more. For example, a vulcanized molded product of a rubber composition containing polybutadiene as a main material is used. Further, the wound core is composed of a center and a thread rubber layer formed by winding thread rubber around the center in a stretched state, and as the wound core, a vulcanized molded article of a rubber composition is used. May use a solid center,
A liquid center using a liquid center in which liquid such as water or paste is sealed in a center cover made of vulcanized rubber may be used.

The golf ball after covering the cover preferably has a ball compression of 2.2 to 4.5 mm, particularly 2.5 to 4.0 mm. The ball compression represents the amount of deformation of the ball from the state where the initial load of 10 kgf is applied to the final load of 130 kgf in mm. When the ball compression is smaller than 2.2 mm, the ball is hit. If the ball feels hard and the ball compression is more than 4.5 mm, the ball becomes too soft, the resilience performance is reduced, and the flight distance may be reduced.

Next, a typical example of the golf ball of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view schematically showing an example of the golf ball of the present invention.
Is a solid golf ball comprising a core 1 made of a vulcanized molded product of a rubber composition and a cover covering the core 1. The core 1 is called a solid core, but is not limited to a specific one. For example, a spherical vulcanized molded product of a rubber composition containing polybutadiene as a main material is used.

The cover 2 is made of a specific cover material as described above.
Consists fee, frequency 10 measured at a heating rate 4 ° C. / min
In the dynamic dispersion curve of dynamic viscoelasticity in Hz, the complex elastic modulus at −10 ° C. at a dynamic strain of 5% is 50 to 1500 kgf /.
cm ² , the resilience of which is measured by a tripsometer is 50% or more.
a is provided. The dimples 2a are provided on the surface of the cover 2 in an appropriate number and in an appropriate manner so as to obtain required or desired characteristics, and paint or marking is applied on the ball surface as necessary. Is done. In the golf ball shown in FIG. 1, the core 1 is formed of a vulcanized molded body of a rubber composition having a one-layer structure, but instead of the core 1, is formed of, for example, a vulcanized molded body of a rubber composition mainly containing polybutadiene. A solid core having a two-layer structure in which an outer core made of a vulcanized molded article of a rubber composition containing polybutadiene as a main component may be further formed around the inner core, or a wound golf ball using a wound core It may be.

[0029]

Next, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to only these examples.

Examples 1 to 5 The golf balls of Examples 1 to 5 were manufactured through the following steps (1) to (5). Preparation of core: polybutadiene [Nippon Synthetic Rubber Co., Ltd.
, BR-11 (trade name)] 100 parts by weight, zinc acrylate 30 parts by weight, zinc oxide 20 parts by weight, dicumyl peroxide 1 part by weight, and antioxidant [Yoshinox, manufactured by Yoshitomi Pharmaceutical Co., Ltd. 425 (trade name)] A rubber composition containing 0.5 part by weight was filled in a mold,
The mixture was vulcanized for 0 minutes to produce a solid core having a diameter of 39.0 mm.

Preparation of cover composition: The compounding materials having the compositions shown in Table 2 were mixed in a twin-screw kneading extruder.
The mixture was mixed at 60 to 180 ° C. to prepare a pellet-shaped cover composition. The amount of each material described in the table is part by weight. In the table, the materials used are SBS, S
It IS, because it is displayed in the generic name of abbreviations and ionomer, such as SE P S, described them in detail before. What
The above SBS, SIS and SEPS are described in detail below.
As is evident from the figure, the styrene-based thermoplastic
I'm a stomer.

SBS: TR27 manufactured by Nippon Synthetic Rubber Co., Ltd.
87 (trade name), a block copolymer having a polystyrene phase in both terminal phases and a polybutadiene phase in the intermediate phase SIS: SIS5000 (trade name) manufactured by Nippon Synthetic Rubber Co., Ltd. Block copolymer having a polyisoprene phase in the phase SEPS: Septon 2002 (trade name) manufactured by Kuraray Co., Ltd. Block copolymer having a polystyrene phase in both terminal phases and a polyolefin phase in the intermediate phase Ionomer: DuPont Mitsui Polychemicals, Ltd. Himilan 1706 (trade name), a sodium ion neutralized product of an ethylene-methacrylic acid copolymer

The complex modulus and rebound resilience of the cover composition prepared as described above were measured. Table 2 also shows the results. The measuring methods of the complex elastic modulus and the rebound resilience are respectively as follows.

Complex elastic modulus: Dynamic viscoelasticity was measured at a frequency of 10 Hz and a heating rate of 4 ° C./min using a DVA-200 manufactured by Shimadzu Corporation as a viscoelastic spectrometer.
The temperature dispersion curve is created, and the complex elastic modulus at −10 ° C. at a dynamic strain of 5% (one-sided amplitude) is obtained.

Rebound resilience: The rebound resilience at a temperature of 23 ° C. is measured by a Dunlop trypsometer.

[0036]

[Table 2]

Preparation of Golf Ball: The cover composition prepared above was injection molded on the solid core prepared above to prepare a golf ball having an outer diameter of 42.7 mm.

With respect to the obtained golf ball, the flight distance,
Ball compression and fryer resistance were examined. The results are shown in Table 3 below. Table 3 also shows the outline of the cover material used and the physical properties of the cover (complex elastic modulus and rebound resilience). The measuring methods of the above flight distance, ball compression and fryer resistance are as follows.

Flying distance: A No. 1 wood club was attached to a swing robot manufactured by True Temper, and the ball was hit at a head speed of 45 m / sec to measure a distance to a drop point. The flight distance is measured for eight balls, and the average value is obtained.

Ball compression: The amount of deformation from when the initial load of 10 kgf is applied to the ball until the final load of 130 kgf is applied is measured.

Flyer resistance: The spin amount P ₁ immediately after the shot when the ball is put on the tee by the pitching wedge and the spin amount P ₂ immediately after the shot when the shot is rough at a depth of 4 cm are measured. ₂ / P
Let ₁ × 100 be the fryer resistance. The closer this value is to 100, the better the fryer resistance (ie, less likely to produce a flyer), and the closer this value is to 0, the poorer the fryer resistance (ie, the more likely it is to produce a fryer).
This flyer resistance is represented by an average score when 10 advanced players hit the ball.

Comparative Examples 1 to 3 A commercially available two-piece solid golf ball using an ionomer-based cover, a commercially available thread-wound golf ball using an ionomer-based cover, and a commercially available thread-wound golf ball using a balata-based cover were obtained. Comparative Example 1,
Comparative Examples 2 and 3 were provided.

For the golf balls of Comparative Examples 1 to 3, the complex elastic modulus, rebound resilience and ball characteristics (flying distance, ball compression and flyer resistance) of the cover were examined in the same manner as in Example 1 above. Are shown in Table 4.

[0044]

[Table 3]

[0045]

[Table 4]

As is clear from the comparison between the ball characteristics of Examples 1 to 5 shown in Table 3 and the ball characteristics of Comparative Examples 1 to 3 shown in Table 4, Examples 1 to 5 show numerical values indicating the fryer resistance. And high flyer resistance compared to Comparative Example 1 which is a commercially available two-piece solid golf ball using an ionomer type cover and Comparative Example 2 which is a commercially available thread wound golf ball using an ionomer type cover. It had a fryer resistance equal to or higher than that of Comparative Example 3 which is a commercially available thread wound golf ball using a system cover. Further, Examples 1 to 5 have the same flight distance as Comparative Example 1 which is a commercially available two-piece solid golf ball using an ionomer type cover and Comparative Example 2 which is a commercially available thread wound golf ball using an ionomer type cover. Have been
Examples 1 to 5 showed high rebound performance, a long flight distance, good fryer resistance, and that a flyer is unlikely to occur even when shot from a rough.

On the other hand, Comparative Example 1 which is a commercially available two-piece solid golf ball using an ionomer type cover and Comparative Example 2 which is a commercially available thread wound golf ball using an ionomer type cover have poor flyer resistance. Comparative Example 3, which is a commercially available thread wound golf ball using a balata-based cover, had good flyer resistance, but was inferior to the golf balls of Examples 1 to 5 in flight distance.

[0048]

As described above, according to the present invention, it is possible to provide a golf ball having high resilience performance, a long flight distance, good flyer resistance, and hardly causing a flyer even when shot from a rough. Was.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing one example of a golf ball of the present invention.

[Explanation of symbols]

 1 core 2 cover

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) A63B 37/12 A63B 37/00

Claims (1)

(57) [Claims] 1. A golf ball having a core and a cover covering the core, wherein the base polymer of the cover is
30% by weight or less of thermoplastic elastomer in base polymer
And the thermoplastic elastomer contains a polystyrene phase.
It has a polybutadiene phase and a polyisophase
Block copoly with plain or polyolefin phase
It is a styrene-based thermoplastic elastomer consisting of
The cover has a frequency 1 measured at a heating rate of 4 ° C./min.
Dynamic strain 5% in temperature dispersion curve of dynamic viscoelasticity at 0 Hz
Has a complex elastic modulus at −10 ° C. of 50 to 1500 kgf
/ Cm ² , and a resilience by a trypsometer of 50% or more.