Patent Application
20190134469
The present invention relates to a colored golf ball.
In general, golf balls are white in appearance. In manufacturing a white golf ball, generally, a white pigment is mixed in a resin of a cover having dimples formed thereon, and a colorless and transparent top coat is formed on the surface of the cover. Sometimes, a bright material is dispersed in the top coat to produce a golf ball having a white pearl tone appearance.
Although a white golf ball provides excellent visibility, a white ball has a problem in that it cannot be easily distinguished from golf balls of other golfers. In view of this problem, balls colored red, blue or other colors are commercially sold, but golfers tend not to use these balls. One reason may be that such colored golf balls lack a luxurious appearance.
JP 2009-045347 A discloses a golf ball that ensures a luxurious appearance without giving golfers any unfamiliar impressions, while providing excellent visibility and distinguishability by using a fluorescent colorant, instead of a titanium oxide which is used as a white colorant, and a polarizing material of composite particles having nuclei of such material as mica coated with a titanium oxide as dispersed in a paint layer over the cover.
In general, in order to obtain a luxurious appearance, dark colors such as black are preferred, as seen in automobiles or lacquerware. If applied to golf balls, however, dark colored golf balls have a problem of remarkably poor visibility during a golf game.
It is therefore an object of the present invention to provide a colored golf ball which has a luxurious appearance without impairing its visibility.
To achieve the above-described object, a golf ball of the present invention includes: a core; a cover placed around the core and having dimples formed on its surface; and a coating layer placed on top of the cover and having a bright material dispersed therein. In the golf ball of the present invention, L0 value, which represents an L (lightness) value in the Lab color system of the colored golf ball before being covered with the coating layer (hereinafter referred to as “L0 value”), is 55 or less, and the difference ΔL between L0 value and L1 value, which represents an L value in the Lab color system of the colored golf ball after being covered with the coating layer (hereinafter referred to as “L1 value”), is 5 or more.
The cover may contain a colorant, so that an L0 value of 55 or less is obtained. Further, in order to obtain an L0 value of 55 or less, a paint layer containing the colorant may be disposed between the coating layer and the cover. Furthermore, in order to obtain an L0 value of 55 or less, an intermediate layer containing the colorant may be disposed between the core and the cover while the cover is made colorless and transparent. Alternatively, a two-piece golf ball, having a core and a colorless and transparent cover, may contain a colorant in the core. The L0 value may be 45 or less.
The L1 value may be 20 or more, or 25 or more, as long as the difference ΔL is 5 or more. The L1 value is preferably 30 or more, more preferably 40 or more, and still more preferably 50 or more.
In the coating layer, it is preferred that the bright material be dispersed in a colorless and transparent polymer matrix.
According to the present invention, even if the golf ball has a very dark color or is colored red, blue or other colors having an L0 value of 55 or less, the bright material is dispersed in the coating layer such that the difference ΔL between the L0 value and L1 value is increased by 5 or more. If so, although the golf ball has a low lightness as a whole, it can provide an improved luxurious appearance without impairing its visibility due to higher polarization property available from the bright material.
An embodiment of a colored golf ball according to the present invention will now be described in detail with reference to the accompanying drawings.
The colored golf ball of this embodiment, as shown in
The core can be formed mainly of a base rubber. As the base rubber, a variety of rubbers may be used, such as polybutadiene rubber (BR), styrene-butadiene rubber (SBR), natural rubber (NR), polyisoprene rubber (IR), polyurethane rubber (PU), silicon rubber, although it is not limited thereto.
As well as the base rubber for the main component, for example, co-crosslinking agent, crosslinking agent, filler, age resistor, isomerization agent, peptizing agent, sulfur and organic sulfur compound may be optionally added to the core. As the main component, thermoplastic elastomer, ionomer resin or a mixture of these components may be used instead of the base rubber.
The core may be solid or hollow, and is substantially spherical. The outer diameter of the core is preferably in a range of 5 to 42 mm, and more preferably in a range of 25 to 40 mm, although it varies depending on whether the intermediate layer is disposed or not. It is permissible to provide an intermediate layer which functions as a core or a cover if the intermediate layer is disposed. As the method of forming the core, any known method of forming the core for a golf ball may be adopted.
The cover 10 is formed using a resin composition for the cover. The resin composition for the cover comprises a resin for the cover as the main component and further contains a colorant. Owning to this, the L0 value can be 55 or less, which shows relatively dark color. The L0 value may be 50 or less, may be 45 or less, may be 40 or less, or may be 35 or less. The lower limit of the L0 value is not restricted to any particular values, but is preferably 5 or more or may be over 25, for example.
As the colorant to obtain an L0 value of 55 or less, it is preferable to use an achromatic colorant such as black or grey colorant or a deep color colorant such as deep blue or red colorant. Specifically, carbon black, etc. can be used as the black colorant, while titanium oxide/carbon black, etc. can be used as the grey colorant. Ultramarine (Gun-jou), etc. can be used as the deep blue colorant, quinacridone red, etc. can be used as the red colorant. Any one of these colorants may be used alone or two or more may be used together. The composition ratio of the colorant in the resin composition for the cover is set as appropriate depending on the L0 value or the kind of the colorant.
As the covering resin, ionomer resin, polyurethane thermoplastic elastomer, thermosetting polyurethane or a mixture of these substances, may be used as the main component to form the cover, although not limited thereto. Furthermore, as well as the aforementioned main component, other thermoplastic elastomer, polyisocyanate compound, fatty acid or its derivative, basic inorganic metal compound or filler may be added to the cover.
As the method of forming the cover 10, any known method of forming the cover for a golf ball may be adopted. For example, the cover may be formed by disposing a core in a mold and injection-molding the resin composition for the cover into the mold such that the cover is placed on top of the core, although the method is not restricted to any particular one. The mold for forming the cover has plural protrusions to form dimples on the surface of the cover. Regarding the thickness of the cover, its lower limit is preferably 0.2 mm or more, and more preferably 0.4 mm or more, and its upper limit is preferably 4 mm or less, more preferably 3 mm or less, and still more preferably 2 mm or less, although it is not limited thereto.
The cover 10 does not need to have an L0 value of 55 or less as a whole, but only needs to have such a value in 50% or more, preferably 70% or more, and more preferably 90% or more thereof so as to provide the golf ball of the present invention having a particular color tone.
In the above embodiment, explanations are given of adding the colorant to the cover to obtain an L0 value of 55 of less. However, the present invention is not restricted thereto. For example, a paint layer may be disposed between the cover and the coating layer so as to ensure an L0 value of 55 or less. In this case, the abovementioned colorant may be used for the paint layer. The thickness of the paint layer is preferably 3 to 30 μm, and more preferably 5 to 20 μm. As an alternative example, the colorant may be added to the intermediate layer disposed between the cover and the core, or the colorant may be added to the core while making the cover colorless and transparent, so that the L0 value can be 55 or less.
The coating layer 20 is formed using a polymer composition for the coating layer. The polymer composition for the coating layer has a polymer for the coating layer as a matrix component, in which the bright material 22 is dispersed in the matrix component. Owning to the coating layer 20 having the polymer matrix 21 in which the bright material 22 is dispersed, the L1 value can be higher than the L0 value by 5 or more (i.e., L1−L0=ΔL≥5). As a result, although the golf ball has a low lightness as a whole, it can provide an improved luxurious appearance without impairing its visibility due to higher polarization property provided by the bright material. The polymer matrix 21 is preferably colorless and transparent.
For example, as shown in
On the other hand, as shown in
The value of ΔL is preferably 10 or more, more preferably 15 or more, still more preferably 20 or more, particularly preferably 25 or more, and most preferably 30 or more, although this is not necessarily restricted to these values since the value of ΔL depends on the L0 value. The L1 value may be, for example, 20 or more, or 25 or more, or is preferably 30 or more, more preferably 40 or more, and still more preferably 50 or more, although this is not necessarily restricted to these values since the L1 value largely depends on the L0 value. The upper limit of the L1 value is preferably 60 or less, although not limited thereto.
As the bright material 22 that is dispersed in the polymer composition for the coating layer, a variety of materials are commercially available. For example, “Iriodin” (registered trademark), “Pyrisma” (registered trademark), “Miraval” (registered trademark), “Colorstream” (registered trademark), and “Xirallic” (registered trademark) are available from Merck Japan. Iriodin is a powder-type inorganic pearlescent pigment in which the surface of a natural mica is coated with metal oxide having a high refractive index such as titanium oxide and iron oxide. Pyrisma is an effect pigment having a high chroma in which mica particles are coated with titanium oxide. Miraval comprises a borosilicate glass as a base material. Colorstream is a pigment comprising a silica flake as a base material, the silica flake being coated with metal oxide such as titanium oxide or iron oxide. Xirallic is a pigment having a high brightness in which an artificially-synthesized alumina flake is coated with metal oxide. Xirallic exhibits a brighter character compared to Iriodin, and does not show a creamy color that is derived from trace impurities such as mica pearl.
The particle diameter of the bright material 22 is, for example, preferably 50 μm or less, and more preferably 30 μm or less, in terms of coating productivity. The lower limit of the particle diameter of the bright material 22 is preferably 5 μm or more, and more preferably 10 μm or more, although this is not limited thereto. The particle diameter is a number average particle diameter measured by “LA-910”, a laser scattering particle size distribution analyzer, manufactured by Horiba, Ltd.
The polymer for the coating layer includes, but is not limited to, polymers such as two-liquid type curable polyurethanes including polyols such as acrylic polyols and polyester polyols as the base polymer, and isocyanates such as hexamethylene diisocyanate (HDI), tolylene diisocyanate (TDI), isophorone diisocyanate (IPDI), diphenylmethane diisocyanate (MDI), and the like as the curing agent. In addition to the above components, the base polymer may include solvents such as ethyl acetate, butyl acetate, propylene glycolmonomethyl ether acetate, methyl ethyl ketone, and methyl isobutyl ketone. In addition, the base polymer may include a curing catalyst to promote curing. However, the polymer composition, preferably, does not include a colorant such that the polymer matrix 21 is made colorless and transparent.
In the coating layer 20, the content of the bright material 22 per 100 parts by weight of the polymer for the coating layer is, for example, preferably 2 to 40 parts by weight, although this varies depending on the kinds of the bright material or the polymer. Even if the golf ball has a dark grey or deep color such as deep blue or red having an L0 value of 55 or less, the golf ball can provide an excellent bright appearance since 2 parts by weight or more of the bright material 22 is dispersed in the coating layer 20. The content of the bright material 22 is more preferably 3 parts by weight or more, and still more preferably 5 parts by weight or more. The greater the content of the bright material 22, the greater the value of ΔL (the difference between L values before and after being coated with the coating layer) becomes, which shows a preferable result. However, if the content of the bright material 22 exceeds a certain limit, its effect is saturated and the ability to mask the lower layer becomes too high. Accordingly, the content of the bright material 22 is preferably 40 parts by weight or less, and more preferably 35 parts by weight or less, and still more preferably 30 parts by weight or less.
To form the coating layer 20, any known coating method for a golf ball may be used. In general, the coating layer is formed by applying its polymer composition to the outer periphery of the cover 10. Regarding the thickness of the coating layer, its lower limit is preferably 3 μm or more, more preferably 5 μm or more, and still more preferably 10 μm or more, and its upper limit is preferably 100 μm or less, and more preferably 60 μm or less, although it is not limited thereto.
Next, examples of the present invention and comparative examples will be described below.
A coating layer for golf balls was formed by using various kinds of bright material. A color tone test for the golf balls before and after being coated with the coating layer was performed. Then, the luxurious appearance and visibility of the golf balls after being coated with the coating layer were evaluated. The results are shown in Tables 1 to 3 and
The color tone test was performed by using a color difference meter (spectrum measuring apparatus “SC-P”, a product of Suga Test Instruments Co., Ltd.) in conformity with JIS Z 8722 “Reflective Object Measurement Methods” (illumination with diffused light, an optical system in which the received light angle is 8°: Condition c), and the color tone was measured by d/8 (measured excluding a regular reflection component of the sample: with an optical trap). The diameter of the measurement hole was 30 mm. Moreover, according to Lab color system under JIS Z 8701, values for L, a, and b were measured.
The evaluation of luxurious appearance was performed by observing the golf ball appearance with the naked eye. For the evaluation criteria for the luxurious appearance, the questionnaire was performed on 50 ordinary golfers. The result was evaluated as “Very good” when 45 or more golfers answered “the golf ball has luxurious appearance”, “Good” when 30 to 44 golfers answered in that way, “Poor” when 6 to 20 golfers answered in that way, and “Bad” when 5 or fewer golfers answered in that way. The evaluation of visibility was performed by observing the golf ball appearance with the naked eye. For the evaluation criteria for the visibility, 50 ordinary golfers observed the golf ball with the naked eye at a distance of 30 yards from the golf ball in an ordinary golf course. The result was evaluated as “Very Good” when 40 or more golfers answered “the golf ball is easy to see on the grass”, “Good” when 25 to 39 golfers answered in that way, “Poor” when 10 to 24 golfers answered in that way, and “Bad” when 9 or fewer golfers answered in that way.
In Comparative Examples 1 to 5 (i.e., C1 to C5 in tables), the white cover of the golf ball having an L0 value of approximately 90 was covered with the coating layer in which the bright material was dispersed. As illustrated in Tables 1 and 2 and
In Comparative Example 8 (i.e., C8 in tables), a black cover was coated with a coating layer containing no bright material therein. The golf ball did not provide any visibility since it was completely black in color. In Comparative Example 9 (i.e., C9 in tables), a blue cover having an L0 value of approximately 40 was covered with the coating layer containing no bright material therein. The golf ball did not provide sufficient visibility since it only showed a blue color.
In Comparative Example 6 (i.e., C6 in tables), an orange cover having an L0 value of approximately 60 was covered with a coating layer in which gold bright material was dispersed. In Comparative Example 7 (i.e., C7 in tables), a yellow cover having an L0 value of approximately 90 was covered with the coating layer in which gold bright material was dispersed. The golf ball in these Examples had an excellent visibility, but lacked the luxurious appearance since the golf ball provided a shiny pearl tone in orange or yellow. On the other hand, in Example 8 (i.e., E8 in tables), a black cover having an L0 value of 20 or less was covered with the coating layer in which gold bright material was dispersed. The golf ball exhibited a sufficient luxurious appearance due to the harmony of black and gold and without any problems of visibility.
In Examples 9 and 10 (i.e., E9 and E10 in tables), grey covers having an L0 value of 25 or less were respectively covered with coating layers in which red and blue bright materials are respectively dispersed. The golf balls in these Examples respectively exhibited the same luxurious appearance and visibility as in Examples 6 and 3 (i.e., E6 and E3 in tables) in which black covers were respectively covered with the coating layers in which the same bright materials are respectively dispersed.
As shown in Table 3 and
On the other hand, in Comparative Example 10 (i.e., C10 in the tables), an orange cover having L0 value of approximately 60 was covered with a coating layer in which a relatively large amount of gold bright material was dispersed. The golf ball in this Example had an excellent visibility, but lacked the luxurious appearance since the golf ball provided a shiny pearl tone in orange, as in the case of Comparative Example 6. In Comparative Example 11 (i.e., C11 in the tables), a red cover having L0 value of approximately 45 was covered with a coating layer in which a relatively small amount of gold bright material was dispersed. The golf ball in this Example does not have any problems of visibility, but lacked the luxurious appearance since the golf ball provided a shiny pearl tone in red.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2016-251084 | Dec 2016 | JP | national |
The present application claims priority to U.S. patent application Ser. No. 15/830,755 filed Dec. 4, 2017, which is incorporated herein by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 15830755 | Dec 2017 | US |
| Child | 16181378 | US |
