Patent Application
20240108947
This non-provisional application claims priority under 35 U.S.C. § 119(a) on Patent Application No. 2022-157579 filed in Japan on Sep. 30, 2022, the entire contents of which are hereby incorporated by reference.
The present invention relates to a golf ball which contains, in a constituent component of the ball such as the core or a cover layer, a material that includes a phase-change material.
Various performances such as flight, feel at impact and durability are desired of golf balls. Designing a golf ball to optimally achieve these performances is often carried out with a typical use environment (e.g., an ambient air temperature of 15 to 30° C.) in mind. However, golf is enjoyed throughout the year, nor are there any limits on the regions where golf balls are used. Golf is thus played in a variety of climates and environments and so a golf ball may be used at, depending on the case, a temperature that is lower or higher than expected. For this reason, the intended performance of a golf ball may not be fully achieved due to the temperature at the time of use. When playing golf in a low-temperature environment in particular, the temperature of the ball decreases in the interval between when the first shot is taken and when the second shot is taken, and so the performance expected on the second shot may not be achieved. Similarly, when playing golf in the summer, the expected performance may not be achieved because the surface temperature of the ball rises on account of, for example, the high ambient air temperature and exposure to direct sunlight.
Various art for minimizing the change in golf ball properties in the winter has hitherto been described. JP-A 2005-74100 discloses the use of a material containing a silicone-polycarbonate copolymer in golf ball components in order to provide golf balls which, even at low temperature, have an excellent feel with no loss of distance. JP-A 2002-272877 describes blending a solution-polymerized styrene-butadiene rubber with an emulsion polymerized styrene-butadiene rubber in a given proportion so as to suppress a decrease in the rebound of the ball and a change in hardness when the ball is used in the winter. JP-A 2001-54593 describes the inclusion of, for example, a specific silane compound or siloxane compound in a golf ball core material in order to provide a core material for golf balls which have both a high hardness and a high rebound resilience and which undergo no change in distance on account of the ambient air temperature. In addition, JP-A 10-309331 and JP-A 10-192448 provide golf balls in which decreases in flight and durability are suppressed even at low temperatures by including an aramid elastomer or a linear low-density polyethylene in the resin material for the outer core layer or the cover.
However, these golf balls are all inventions which focus on compounding, with the base rubber or base resin of a golf ball component, materials whose changes in properties in response to temperature changes are small, and do not constitute art that stabilizes the temperature of materials that have been selected and used in order to obtain optimal properties as a golf ball.
Also, golf balls which reduce the degree of change in hardness or rebound in response to a change in the temperature of the ball during the winter by setting the compressive hardness of the ball to a low value are available on the market. Yet, these commercial golf balls have designs whose priority is to reduce changes in the ball properties during the winter, and are not designed to suppress changes in the ball temperature itself.
It is therefore an object of the present invention to provide a golf ball which, by suppressing changes in the ball temperature itself in response to changes in the ambient air temperature during use of the ball, is able to maintain the optimal properties that have been designed into the ball.
As a result of intensive investigations, I have found that by including a phase-change material (PCM) in components making up a golf ball such as the coating layer, cover layer, intermediate layer and core, changes in the ball temperature itself in response to changes in the ambient air temperature during use of the ball can be suppressed and the optimal properties that have been designed into the ball maintained, with changes in the feel of the ball at impact in particular being suppressed, thus making it possible for the golfer to play the ball with confidence.
That is, by introducing a phase-change material into part of the golf ball and thereby ensuring a phase-change time at which a pre-selected and discretionary temperature (phase-change temperature) is exceeded when a change in the ambient air temperature change arises, the rate of temperature change by the golf ball slows, which has the effect of prolonging the time during which the design properties of the ball are achieved. Also, it is possible to adjust these effects by suitably adjusting the amount of phase-change material added.
Accordingly, the invention provides a golf ball having a golf ball component which includes a material that contains a phase change material (PCM).
In a preferred embodiment of the golf ball of the invention, the PCM has a melting point of between 5° C. and 40° C.
In another preferred embodiment of the inventive golf ball, the PCM-containing material is in the form of microcapsules. The microcapsules may have a membrane material which includes a thermosetting resin.
In yet another preferred embodiment, the PCM is a paraffinic substance having a melting point of between 5° C. and 40° C. The PCM is preferably normal paraffin. The normal paraffin may have from 14 to 20 carbon atoms.
In still another preferred embodiment, the PCM-containing material includes a supercooling inhibitor.
In a further preferred embodiment, the PCM-containing material is included in one or more golf ball component selected from the group consisting of a coating layer, a cover layer, an intermediate layer and a core.
In a still further preferred embodiment, the PCM-containing material is included in the golf ball component in a weight ratio of 5 wt % or more.
The golf ball of the invention, by suppressing changes in the ball temperature itself in response to changes in the ambient air temperature during use of the ball, can maintain the optimal properties designed into the ball. Moreover, by maintaining the optimal properties, changes in the feel of the ball at impact are suppressed, making it possible for the golfer to play the ball with confidence.
The objects, features and advantages of the invention will become more apparent from the following detailed description.
This invention is characterized by including a phase-change material (PCM)-containing material within a golf ball component so as to introduce the PCM into at least part of the golf ball.
The phase-change material is abbreviated below simply as “PCM” and the material containing the PCM is referred to as the “PCM-containing material.”
The PCM is not limited so long as it is a substance which changes phase within the ambient temperature range at which golf balls are used, and may be a single substance or a mixture of two or more substances. Specific examples include paraffin waxes such as normal paraffin, hydrates such as sodium acetate trihydrate and sodium sulfate decahydrate, and fatty acids. Of these, at the ambient temperature at which golf balls are used, normal paraffin is preferred as the PCM. The phase-change temperature can be adjusted as desired by suitably selecting the number of carbon atoms on the normal paraffin.
The types and melting points of the normal paraffins preferably used in this invention are shown in the table below. As shown in the table, it is desirable to use a normal paraffin having a melting point of between 5° C. and 40° C. and from 14 to 20 carbon atoms as the PCM.
When a PCM has cooled, it sometimes gives rise to supercooling. In such cases, transition at the intended temperature does not arise and so the expected effect for a golf ball in which PCM has been introduced may not be obtained. For this reason, a supercooling inhibitor may be included beforehand in the PCM-containing material used in the invention. In this way, the melting temperature and freezing temperature at which phase transition occurs will coincide, enabling the effects due to PCM incorporation to be reliably achieved. The supercooling inhibitor is not particularly limited and may be suitably selected according to the type of PCM used. For example, an organic compound having a higher melting point than the PCM may be used. Specifically, an n-paraffin derivative such as an n-alkyl alcohol or an n-alkyl amine may be suitably selected.
The PCM content per 100 wt % of a single golf ball component is preferably at least 5 wt %, more preferably at least 10 wt %, even more preferably at least 15 wt %, and most preferably at least 20 wt %. To prevent the PCM from compromising the intrinsic functionality of the base resin (matrix) in the golf ball component, the upper limit of this content is preferably not more than 70 wt %, and more preferably not more than 60 wt %. The preferred range in the PCM content differs according to the type of golf ball component. Also, given that the PCM-containing component is not limited to one golf ball component and may be a plurality of golf ball components, the above PCM content is suitably selected according to the particular embodiment.
The PCM-containing material used in this invention may also optionally include, for example, a thickener and an antioxidant.
No limitation is imposed on the golf ball component in which the PCM-containing material is included, so long as it is a constituent component of the golf ball. The target component may be, for example, the coating layer, cover layer, intermediate layer or core of the golf ball. Nor is the component limited to only one of these; the PCM-containing material may be included in two or more such components.
When the PCM-containing material is included in the core, a golf ball core which includes the PCM-containing material can be fabricated by preparing a rubber composition that includes the PCM-containing material along with various other ingredients such as a base rubber, a co-crosslinking agent, an inorganic filler and an organic peroxide, and vulcanizing the rubber composition.
When the PCM-containing material is included in the intermediate layer or the cover layer, the PCM-containing material is incorporated into the ionomer resin, polyurethane resin or other known golf ball resin material serving as the chief material of the intermediate layer or the cover layer, and this resin material is formed by a known molding process such as injection molding into a resin layer that includes the PCM-containing material and can be used as the intermediate layer or the cover layer.
When the PCM-containing material is included in the coating layer, a coating layer which includes the PCM-containing material can be formed by blending the PCM-containing material with a base resin composition of polyester polyol or the like in a known coating composition used in golf balls and then applying this coating composition onto the surface of the golf ball via an ordinary painting operation.
The PCM-containing material is not limited as to the form thereof, and can be used in a known form such as a liquid, a gel or microcapsules. In order to be able to easily incorporate the PCM in various golf ball members, the incorporation of microencapsulated PCM is especially preferred. In this case, the membrane material of the microcapsules is not particularly limited. However, when the PCM is added to a resin or rubber, given the need to maintain the capsule form during processing, a thermosetting resin such as melamine resin or a resin material having impact resistance such as acrylic resin may be selected.
A commercial product may be used as the above PCM-containing material. Examples include the PMCD-SP series of thermal storage paraffins available from Mikiriken Industrial Co., Ltd. under the following trade names: PMCD-5SP (melting point, about 5° C.), PMCD-15SP (melting point, about 15° C.), PMCD-25SP (melting point, about 25° C.), PMCD-28SP (melting point, about 28° C.) and PMCD-32SP (melting point, about 32° C.).
The following Examples and Comparative Examples are provided to illustrate the invention, and are not intended to limit the scope thereof.
Basic Formulations I to III below for different ball components are used. The PCM-containing materials are suitably prepared and included in these basic formulations.
Basic Formulation I for Core
The basic core formulation is shown in Table 2. Cores having a diameter of 36.3 mm are produced by preparing core-forming rubber compositions which include, as shown subsequently in Tables 5 to 7, given amounts of the PCM-containing material per 100 parts by weight of this basic formulation, and then molding and vulcanizing the compositions for 15 minutes at 155° C.
Details on the above core ingredients are provided below.
Basic Formulation II for Cover Layers
Basic formulations for the cover layers are shown in Table 3. Cover layers (in order from the inside: an envelope layer, an intermediate layer and an outermost layer) formulated of various resin materials are successively injection-molded over the core using injection-molding resin materials which include, as shown subsequently in Tables 5 to 7, given amounts of the PCM-containing material per 100 parts by weight of these basic formulations. The envelope layer has a thickness of 1.3 mm and a material hardness on the Shore D hardness scale of 52, the intermediate layer has a thickness of 1.1 mm and a material hardness on the Shore D hardness scale of 62, and the outermost layer has a thickness of 0.8 mm and a material hardness on the Shore D hardness scale of 47. When the outermost layer is injection molded, numerous dimples are formed at the same time on the outside surface thereof.
Details on the cover (envelope layer, intermediate layer and outermost layer) ingredients are provided below.
Basic Formulation I for Coating
The basic coating formulation is shown in Table 4. A coating layer having a thickness of 15 μm is formed by preparing a coating composition which includes, as shown subsequently in Tables 5 to 7, a specific amount of the PCM-containing material per 100 parts by weight of this basic formulation, and then applying this composition with an air spray gun onto the surface of the outermost layer where numerous dimples have been formed.
Polyester Polyol (A) Synthesis Example
A reactor equipped with a reflux condenser, a dropping funnel, a gas inlet and a thermometer is charged with 140 parts by weight of trimethylolpropane, 95 parts by weight of ethylene glycol, 157 parts by weight of adipic acid and 58 parts by weight of 1,4-cyclohexanedimethanol, following which the temperature is raised to between 200° C. and 240° C. under stirring and the reaction is effected by 5 hours of heating. This yield Polyester Polyol (A) having an acid value of 4, a hydroxyl value of 170 and a weight-average molecular weight (Mw) of 28,000.
As indicated above, the Polyester Polyol (A) alone is dissolved as the base resin in butyl acetate without the admixture of Polyester Polyol (B). This solution has a nonvolatiles content of 27.5 wt %.
Next, the isocyanate shown in the above table is dissolved in an organic solvent and used as the curing agent. That is, the coating is prepared by adding HMDI isocyanurate (Duranate TPA-100 from Asahi Kasei Corporation; NCO content, 23.1%; nonvolatiles content, 100%) and ethyl acetate and butyl acetate as the organic solvents in the compounding ratio shown in the table.
Evaluation samples (Nos. 1 to 8) of the golf balls are held isothermally at 24° C., and the feel at impact on shots with a number six iron (I #6) and shots with a putter are each evaluated. The procedure consists of letting the golf ball stand 5 minutes in a 0° C. thermostatic chamber, then removing the golf ball and evaluating its feel at impact according to the criteria shown below. Holding the golf ball for 5 minutes in a 0° C. thermostatic chamber simulates conditions on the second shot of a hole during a round of golf played in a low-temperature environment, the assumption being that on the first shot the ball is hit shortly after it is taken out of the golfer's pocket or a golf bag and so the length of exposure by the ball to a low temperature is short.
Evaluation Criteria
Here, a “normal feel” refers to the feel of the golf ball in a 24° C. environment.
PCM-Containing Material (1) in the above table is the product having the trade name PMCD-15SP (melting point, about 15° C.; active ingredient, 75%) in the PMCD-SP series of thermal storage paraffins available from Mikiriken Industrial Co., Ltd. This product in the form of microcapsules in which the capsule shells are made of melamine resin.
Evaluation samples (Nos. 1 and 9 to 15) of the golf balls are held isothermally at 24° C., and the feel at impact on shots with a number six iron (I #6) and shots with a putter are each evaluated. The procedure consists of letting the golf ball stand 5 minutes in a 40° C. thermostatic chamber, then removing the golf ball and evaluating its feel at impact according to the criteria shown below. Holding the golf ball for 5 minutes in a 40° C. thermostatic chamber simulates conditions on the second shot of a hole during a round of golf played in a high-temperature environment, the assumption being that on the first shot the ball is hit shortly after being taken out of the golfer's pocket or a golf bag and so the length of exposure by the ball to a high temperature is short.
Evaluation Criteria
PCM-Containing Material (2) in the above table is the product having the trade name PMCD-28SP (melting point, about 28° C.; active ingredient, 75%) in the PMCD-SP series of thermal storage paraffins available from Mikiriken Industrial Co., Ltd. This product is in the form of microcapsules in which the capsule shells are made of melamine resin.
Evaluation samples (Nos. 1 and 9 to 15) of the golf balls are held isothermally at 24° C., and the feel at impact on shots with a number six iron (I #6) and shots with a putter are each evaluated. The procedure consists of setting a 100 kW infrared lamp 40 cm above each golf ball sample, irradiating the ball for 5 minutes, and then removing the golf ball and evaluating its feel according to the criteria shown below. Here, irradiating a golf ball from above with infrared rays simulates the conditions under which the ball undergoes a temperature change from exposure to direct sunlight, such as occurs when playing an actual round of golf.
Evaluation Criteria
It is apparent from Tables 5 to 7 that, although the change in feel at impact does increase or decrease depending on the proportion of PCM-containing material included in the various golf ball components, the change in feel can be made smaller by including at least 15 parts by weight of PCM-containing material per 100 parts by weight of the respective golf ball components. Yet, when a PCM-containing material is included in the core, at an amount of PCM-containing material set to 20 parts by weight, there is no change in feel on shots with a number six iron (I #6), which is good, but the change in feel on shots with a putter cannot be kept low. The reason appears to be that, on shots with a putter, of the components making up the golf ball, although the outer surface portion is affected, such effects do not extend down to the core. A smaller change in feel on shots with a putter is thought to be achievable by, as shown in the above tables, including a given amount or more of the PCM-containing material within the outermost layer or the coating.
Japanese Patent Application No. 2022-157579 is incorporated herein by reference. Although some preferred embodiments have been described, many modifications and variations may be made thereto in light of the above teachings. It is therefore to be understood that the invention may be practiced otherwise than as specifically described without departing from the scope of the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2022-157579 | Sep 2022 | JP | national |
