golf ball

Abstract

The objective is to improve the moldability of golf ball covers containing polyurethane as a resin component, while suppressing a decrease in the scratch resistance of the cover, thereby increasing the productivity of golf balls. [Solution] The golf ball has a spherical core and a cover covering the spherical core, wherein the cover contains (A) thermoplastic polyurethane as a resin component, and when the cover is measured with a Fourier transform infrared spectrophotometer under predetermined measurement conditions, the difference Δν(ν1-ν2) between the wavenumber (ν1) of the absorption peak based on NH groups in the (A) thermoplastic polyurethane that do not form hydrogen bonds and the wavenumber (ν2) of the absorption peak based on NH groups that form hydrogen bonds with the carbonyl oxygen of the urethane groups in the (A) thermoplastic polyurethane is 100.0 cm². -1 ~109.0cm -1 It is characterized by being such.

Description

[Technical Field]

[0001] This invention relates to golf balls, and more particularly to improving the moldability of polyurethane covers. [Background technology]

[0002] Traditionally, ionomer resins and polyurethanes have been used as resin components for golf ball covers. Covers made with ionomer resins tend to have superior rebound, durability, and processability. Covers made with polyurethanes tend to improve feel and spin performance. Cover materials combining these ionomer resins and polyurethanes have also been proposed.

[0003] For example, Patent Document 1 describes a golf ball cover material containing a thermoplastic polyurethane elastomer, an ethylene-acrylic acid ester-glycidyl methacrylate terpolymer, and magnesium stearate (see Patent Document 1 (Table 1)). Patent Document 2 describes a cover composition containing as the main components a heated mixture of (a) 60 to 95% by weight of a polyurethane thermoplastic elastomer and (b) 5 to 40% by weight of an ethylene-(meth)acrylic acid-(meth)acrylic acid ester ternary copolymer ionomer resin (see Patent Document 2 (Table 2)).

[0004] Furthermore, Patent Document 3 describes a golf ball formed from a cover material whose main components are a heated mixture comprising: (A) 60-90% by mass of a metal ion neutralized product of an olefin-unsaturated carboxylic acid copolymer and / or a metal ion neutralized product of an olefin-unsaturated carboxylic acid-unsaturated carboxylic acid ester copolymer (wherein 40-80% by mass of component (A) is an ionomer neutralized by alkali metal ions); (B) 5-20% by mass of an olefin-unsaturated carboxylic acid copolymer and / or an olefin-unsaturated carboxylic acid-unsaturated carboxylic acid ester copolymer consisting of at least one type; and (C) 2-30% by mass of a thermoplastic polyurethane elastomer (see Patent Document 3 (Table 3)). [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 11-128402 [Patent Document 2] Japanese Patent Publication No. 2003-180878 [Patent Document 3] Japanese Patent Publication No. 2007-125377 [Overview of the project] [Problems that the invention aims to solve]

[0006] When polyurethane is used as the main resin component in a cover composition, the fluidity of the cover composition tends to decrease, making it difficult to mold the cover. Adding ionomer resin to a polyurethane-containing cover composition can improve its fluidity. However, adding ionomer resin to polyurethane presents a problem: it reduces the scratch resistance of the resulting cover.

[0007] This invention has been made in view of the above circumstances, and aims to improve the moldability of a golf ball cover containing polyurethane as a resin component, while suppressing a decrease in the scratch resistance of the cover, thereby increasing the productivity of golf balls. [Means for solving the problem]

[0008] The golf ball of the present invention that has solved the above problems has a spherical core and a cover that covers the spherical core, the cover contains (A) thermoplastic polyurethane as a resin component, and when the cover is measured with a Fourier transform infrared spectrophotometer under the following measurement conditions, the difference Δν (ν1 - ν2) between the wave number (ν1) of the absorption peak based on the N-H group that does not form a hydrogen bond in the (A) thermoplastic polyurethane and the wave number (ν2) of the absorption peak based on the N-H group that forms a hydrogen bond with the carbonyl oxygen of the urethane group in the (A) thermoplastic polyurethane is 100.0 cm -1 ~109.0 cm -1 It is characterized by being as follows. <Measurement Conditions> Measurement method: Single reflection ATR (Attenuated Total Reflection) method Measurement range: 400 cm -1 ~4000 cm -1 Resolution: 4 cm -1 Number of integrations: 32 times Crystal: Diamond Temperature increase rate: 10 °C / min Measurement temperature: 190 °C

Advantages of the Invention

[0009] According to the present invention, for a golf ball having a cover containing polyurethane as a resin component, it is possible to improve the moldability of the cover while suppressing a decrease in the scratch resistance of the cover, and to enhance the productivity of the golf ball.

Brief Description of the Drawings

[0010] [Figure 1] A partially cut-away cross-sectional view showing a golf ball according to an embodiment of the present invention. [Figure 2] IR spectra of cover compositions No. 1, 4, and 6.

Modes for Carrying Out the Invention

[0011] The golf ball of the present invention has a spherical core and a cover covering the spherical core, and the cover contains (A) thermoplastic polyurethane as a resin component. When measured with a Fourier transform infrared spectrophotometer under the measurement conditions described later, the cover has a wavenumber (ν1) of an absorption peak based on an N-H group that does not form a hydrogen bond in the (A) thermoplastic polyurethane, and a wavenumber (ν2) of an absorption peak based on an N-H group that forms a hydrogen bond with a carbonyl oxygen of a urethane group in the (A) thermoplastic polyurethane. The difference Δν (ν1 - ν2) is 100.0 cm -1 ~109.0 cm -1 It is characterized by being.

[0012] Polyurethane has a plurality of urethane bonds (-NH-COO-) in the molecule, and a part of the NH groups in the polyurethane forms a hydrogen bond with the carbonyl bond (CO group) of the urethane group. In Fourier transform infrared spectroscopy, the absorption based on the NH group that is not hydrogen-bonded appears around 3450 cm -1 and the absorption based on the NH group that forms a hydrogen bond with the carbonyl bond of the urethane group appears at 3355 cm -1 ~3300 cm -1 Here, the absorption wavenumber of the stretching vibration of the NH group that forms a hydrogen bond depends on the strength of the hydrogen bond. As the bond becomes stronger, the absorption peak moves to the low wavenumber side, and as the bond becomes weaker, the absorption peak moves to the high wavenumber side. Therefore, by controlling the difference Δν (ν1 - ν2) to 100.0 cm -1 ~109.0 cm -1 the strength of the hydrogen bond can be relaxed, and while suppressing the decrease in the scratch resistance of the cover, the moldability of the cover can be improved.

[0013] The difference Δν (ν1 - ν2) is preferably 100.0 cm -1 or more, more preferably 100.5 m -1 or more, still more preferably 101.0 cm -1 or more, and preferably 109.0 cm -1 or less, more preferably 108.0 cm -1 or less, still more preferably 107.0 cm -1The following applies:

[0014] The thickness of the cover is preferably 0.3 mm or more, more preferably 0.4 mm or more, even more preferably 0.5 mm or more, preferably 2.0 mm or less, more preferably 1.8 mm or less, and even more preferably 1.6 mm or less. If the cover thickness is 0.3 mm or more, the cover is easier to mold, and if it is 2.0 mm or less, the diameter of the core can be relatively increased, thus improving the rebound performance of the golf ball.

[0015] [Composition for covering] The cover can be formed from a cover composition. The cover composition used in the golf ball of the present invention will be described below.

[0016] ((A) Thermoplastic polyurethane) The aforementioned cover composition contains (A) thermoplastic polyurethane as a resin component. The thermoplastic polyurethane (A) described above has multiple urethane bonds within its molecule and exhibits thermoplasticity. Thermoplastic polyurethane is a polyurethane that exhibits plasticity upon heating, and generally refers to a polyurethane having a linear structure with a relatively high molecular weight. An example of the thermoplastic polyurethane (A) described above is a product formed by reacting a polyisocyanate with a polyol, in which urethane bonds are formed within the molecule.

[0017] The polyisocyanate constituting the thermoplastic polyurethane (A) is not particularly limited as long as it is a compound having two or more isocyanate groups in its molecule. The polyisocyanate may be used alone or in combination of two or more. The polyisocyanate is preferably a diisocyanate having two isocyanate groups in its molecule.

[0018] Examples of the aforementioned polyisocyanates include aromatic polyisocyanates such as 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, a mixture of 2,4-toluene diisocyanate and 2,6-toluene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate (MDI), 1,5-naphthylene diisocyanate (NDI), 3,3'-vitrylene-4,4'-diisocyanate (TODI), xylylene diisocyanate (XDI), tetramethyl xylylene diisocyanate (TMXDI), and paraphenylenedi diisocyanate (PPDI); and 4,4'-dicyclohexylmethane diisocyanate (H 12 Examples include alicyclic polyisocyanates or aliphatic polyisocyanates such as MDI, 1,3-bis(isocyanatomethyl)cyclohexane (H6XDI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), trans-1,4-cyclohexane diisocyanate (CHDI), and norbornene diisocyanate (NBDI). Among these, alicyclic diisocyanates and / or aromatic diisocyanates are preferred as polyisocyanates. By using alicyclic diisocyanates and / or aromatic diisocyanates, the mechanical properties of the resulting polyurethane are improved, and the scratch resistance of the resulting cover is further enhanced.

[0019] The polyisocyanate of the thermoplastic polyurethane (A) is 4,4'-dicyclohexylmethane diisocyanate (H 12 Particularly preferred are at least one diisocyanate selected from the group consisting of MDI, 1,3-bis(isocyanatomethyl)cyclohexane (H6XDI), isophorone diisocyanate (IPDI), trans-1,4-cyclohexane diisocyanate (CHDI), 4,4'-diphenylmethane diisocyanate (MDI), and toluene diisocyanate (TDI). The use of these diisocyanates improves the mechanical properties of the resulting polyurethane and further enhances the scratch resistance of the resulting cover.

[0020] The polyol constituting the thermoplastic polyurethane (A) is not particularly limited as long as it is a compound having two or more hydroxyl groups in its molecule, but examples include high molecular weight polyols. The high molecular weight polyol may be used alone or in combination of two or more. As the polyol, a diol having two hydroxyl groups in its molecule is preferred.

[0021] Examples of the high molecular weight polyols include polyether polyols such as polyoxyethylene glycol (PEG), polyoxypropylene glycol (PPG), polytrimethylene ether glycol (PO3G), and polyoxytetramethylene glycol (PTMG); condensed polyester polyols such as polyethylene adipate (PEA), polybutylene adipate (PBA), and polyhexamethylene adipate (PHMA); lactone-based polyester polyols such as poly-ε-caprolactone (PCL); polycarbonate polyols such as polyhexamethylene carbonate; and acrylic polyols. The high molecular weight polyols may be derived from petroleum resources or from biomass resources.

[0022] The number-average molecular weight of the high molecular weight polyol is not particularly limited, but is preferably 400 or more, more preferably 1,000 or more, 10,000 or less, and more preferably 8,000 or less.

[0023] The thermoplastic polyurethane (A) may contain a chain extender as a component. Low molecular weight polyols, low molecular weight polyamines, and the like can be used as the chain extender component.

[0024] Examples of the low molecular weight polyols include ethylene glycol, diethylene glycol, triethylene glycol, propanediols (e.g., 1,2-propanediol, 1,3-propanediol, 2-methyl-1,3-propanediol, etc.), dipropylene glycol, butanediols (e.g., 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 2,3-dimethyl-2,3-butanediol, etc.), neopentyl glycol, pentanediol, hexanediol, heptanediol, octanediol, 1,6-cyclohexanedimethylol, aniline diols, bisphenol A diols, and other diols; triols such as glycerin, trimethylolpropane, and hexanetriol; and tetraols or hexaols such as pentaerythritol and sorbitol.

[0025] The low molecular weight polyamine used as a chain extender component is not particularly limited as long as it has at least two amino groups. Examples of such polyamines include aliphatic polyamines such as ethylenediamine, propylenediamine, butylenediamine, and hexamethylenediamine; alicyclic polyamines such as isophoronediamine and piperazine; and aromatic polyamines.

[0026] The aromatic polyamine is not particularly limited as long as at least two amino groups are directly or indirectly bonded to the aromatic ring. Here, indirect bonding means that the amino groups are bonded to the aromatic ring, for example, via lower alkylene groups. The aromatic polyamine may be, for example, a monocyclic aromatic polyamine in which two or more amino groups are bonded to one aromatic ring, or a polycyclic aromatic polyamine containing two or more aminophenyl groups in which at least one amino group is bonded to one aromatic ring.

[0027] Examples of the monocyclic aromatic polyamines include types in which the amino group is directly bonded to the aromatic ring, such as phenylenediamine, toluenediamine, diethyltoluenediamine, and dimethylthiotoluenediamine; and types in which the amino group is bonded to the aromatic ring via a lower alkylene group, such as xylylenediamine. Furthermore, the polycyclic aromatic polyamine may be a poly(aminobenzene) in which at least two aminophenyl groups are directly bonded, or it may be a poly(aminobenzene) in which at least two aminophenyl groups are bonded via a lower alkylene group or an alkylene oxide group. Of these, diaminodiphenylalkanes in which two aminophenyl groups are bonded via a lower alkylene group are preferred, and 4,4'-diaminodiphenylmethane and its derivatives are particularly preferred.

[0028] The molecular weight of the chain extender is preferably less than 400, more preferably 350 or less, even more preferably 200 or less, preferably 30 or more, more preferably 40 or more, and even more preferably 45 or more.

[0029] The constituent configuration of the thermoplastic polyurethane (A) is not particularly limited, but examples include a configuration composed of polyisocyanate and a high molecular weight polyol; a configuration composed of polyisocyanate, a high molecular weight polyol and a low molecular weight polyol; a configuration composed of polyisocyanate, a high molecular weight polyol and a low molecular weight polyol and a polyamine; and a configuration composed of polyisocyanate, a high molecular weight polyol and a polyamine. In particular, a configuration composed of diisocyanate and a diol is preferred for the constituent configuration of the thermoplastic polyurethane (A), and a configuration composed of diisocyanate, a high molecular weight diol and a low molecular weight diol is more preferred.

[0030] The polyol content in 100% by mass of the thermoplastic polyurethane (A) is preferably 10% by mass or more, more preferably 15% by mass or more, even more preferably 20% by mass or more, preferably 90% by mass or less, more preferably 85% by mass or less, and even more preferably 80% by mass or less. The polyisocyanate content in 100% by mass of the thermoplastic polyurethane (A) is preferably 10% by mass or more, more preferably 15% by mass or more, even more preferably 20% by mass or more, preferably 90% by mass or less, more preferably 85% by mass or less, and even more preferably 80% by mass or less.

[0031] The slab hardness of the thermoplastic polyurethane (A) is preferably 80.0 or higher on the Shore A hardness scale, more preferably 85.0 or higher, even more preferably 90.0 or higher, preferably 97.0 or lower, more preferably 96.0 or lower, and even more preferably 95.0 or lower. If the hardness of the thermoplastic polyurethane (A) is 80.0 or higher on the Shore A hardness scale, the amount of spin in driver shots can be reduced, and if it is 97.0 or lower, the amount of spin in approach shots can be increased.

[0032] The content of thermoplastic polyurethane (A) in the resin component is preferably 50% by mass or more, more preferably 55% by mass or more, even more preferably 60% by mass or more, particularly preferably 80% by mass or more, preferably 99.9% by mass or less, more preferably 99% by mass or less, even more preferably 98% by mass or less, and most preferably 95% by mass or less. If the content of component (A) is 50% by mass or more, the scratch resistance of the cover will be better, and if it is 99.9% by mass or less, the moldability of the cover composition will be better.

[0033] ((B) Olefin-unsaturated carboxylic acid copolymer and / or olefin-unsaturated carboxylic acid-unsaturated carboxylic acid ester copolymer) The cover composition preferably contains (B) olefin-unsaturated carboxylic acid copolymer and / or olefin-unsaturated carboxylic acid-unsaturated carboxylic acid ester copolymer as a resin component. (B) olefin-unsaturated carboxylic acid copolymer and / or olefin-unsaturated carboxylic acid-unsaturated carboxylic acid ester copolymer may be used alone or in combination of two or more types.

[0034] By incorporating (B) an olefin-unsaturated carboxylic acid copolymer and / or an olefin-unsaturated carboxylic acid-unsaturated carboxylic acid ester copolymer as the resin component of the cover composition, the cohesive force of the urethane groups constituting the hard segments in (A) thermoplastic polyurethane can be reduced.

[0035] The olefin-unsaturated carboxylic acid copolymer is a binary copolymer of an olefin and an unsaturated carboxylic acid (hereinafter sometimes referred to as "(B1) binary copolymer"). The olefin-unsaturated carboxylic acid-unsaturated carboxylic acid ester copolymer is a terpolymer of an olefin, an unsaturated carboxylic acid, and an unsaturated carboxylic acid ester (hereinafter sometimes referred to as "(B2) terpolymer"). The (B) olefin-unsaturated carboxylic acid copolymer and / or olefin-unsaturated carboxylic acid-unsaturated carboxylic acid ester copolymer may consist of only the (B1) binary copolymer or only the (B2) terpolymer. Alternatively, the (B1) binary copolymer and the (B2) terpolymer may be used in combination.

[0036] The olefin is preferably an olefin having 2 to 8 carbon atoms, and more preferably an olefin having 2 to 4 carbon atoms. Examples of the olefin include ethylene, propylene, butene, pentene, hexene, heptene, octene, and the like, with ethylene being particularly preferred.

[0037] The unsaturated carboxylic acid is preferably an α,β-unsaturated carboxylic acid, and more preferably an α,β-unsaturated carboxylic acid having 3 to 8 carbon atoms. Examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, fumaric acid, maleic acid, and crotonic acid, with acrylic acid or methacrylic acid being particularly preferred.

[0038] The unsaturated carboxylic acid ester is preferably an α,β-unsaturated carboxylic acid ester, and more preferably an alkyl ester of an α,β-unsaturated carboxylic acid having 3 to 8 carbon atoms. The unsaturated carboxylic acid ester is more preferably an alkyl ester of acrylic acid, methacrylic acid, fumaric acid, or maleic acid, and particularly preferably an alkyl ester of acrylate or an alkyl ester of methacrylate. Examples of alkyl groups constituting the ester include a methyl group, an ethyl group, a propyl group, an n-butyl group, and an isobutyl group. The unsaturated carboxylic acid ester is preferably methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, or isobutyl (meth)acrylate. In this specification, (meth)acrylic acid means acrylic acid and / or methacrylic acid.

[0039] The (B1) binary copolymer is preferably a binary copolymer of ethylene and an α,β-unsaturated carboxylic acid having 3 to 8 carbon atoms, and more preferably an ethylene-(meth)acrylic acid binary copolymer. The (B2) terpolymer is preferably a terpolymer of ethylene, an α,β-unsaturated carboxylic acid having 3 to 8 carbon atoms, and an alkyl ester of an α,β-unsaturated carboxylic acid having 3 to 8 carbon atoms, and more preferably an ethylene-(meth)acrylic acid-(meth)acrylic acid alkyl ester terpolymer.

[0040] The content of the unsaturated carboxylic acid component in the (B1) binary copolymer is preferably 1% by mass or more, more preferably 3% by mass or more, even more preferably 5% by mass or more, preferably 50% by mass or less, more preferably 45% by mass or less, and even more preferably 40% by mass or less. If the content of the unsaturated carboxylic acid component is within the above range, the compatibility with (A) thermoplastic polyurethane will be even better.

[0041] The content of the unsaturated carboxylic acid component in the (B2) ternary copolymer is preferably 1% by mass or more, more preferably 3% by mass or more, even more preferably 5% by mass or more, preferably 50% by mass or less, more preferably 45% by mass or less, and even more preferably 40% by mass or less. If the content of the unsaturated carboxylic acid component is within the above range, the compatibility with (A) thermoplastic polyurethane will be even better.

[0042] The melt flow rate (MFR) (190°C, 2.16 kg load) of the (B) olefin-unsaturated carboxylic acid copolymer and / or olefin-unsaturated carboxylic acid-unsaturated carboxylic acid ester copolymer is preferably 10 g / 10 min or more, more preferably 15 g / 10 min or more, even more preferably 25 g / 10 min or more, preferably 1000 g / 10 min or less, more preferably 900 g / 10 min or less, and even more preferably 800 g / 10 min or less. If the MFR (190°C, 2.16 kg load) of component (B) is 10 g / 10 min or more, the fluidity of the cover composition will be better. Also, if the MFR (190°C, 2.16 kg load) of component (B) is 1000 g / 10 min or less, the impact durability of the resulting cover will be better. The MFR is measured using a flow tester in accordance with JIS K7210. If multiple types of component (B) are used in combination, the MFR of these mixtures is measured.

[0043] The melting point of the (B) olefin-unsaturated carboxylic acid copolymer and / or olefin-unsaturated carboxylic acid-unsaturated carboxylic acid ester copolymer is preferably 120°C or lower, more preferably 118°C or lower, and even more preferably 115°C or lower. The melting point of component (B) is preferably 75°C or higher.

[0044] Examples of component (B) include Nucrel® N2050H, N2060, N1050H, N1560, N1525, AN4221C, AN4213C, N1110H, AN4229C, N11081C, N1108C, N1035, N035C, N0908C, AN42012C, N0903HC, N0823, AN42115C, AN4228C, AN4214C, N0200H, AN4233C (manufactured by Mitsui Dow Polychemical); and Primacol® 1321, 1410, 1430, 3002, 3003, 3004, 3330, 3340, 3440, 3460 (manufactured by SK Geo Centric).

[0045] The content of (B) olefin-unsaturated carboxylic acid copolymer and olefin-unsaturated carboxylic acid-unsaturated carboxylic acid ester copolymer in the resin component is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 1% by mass or more, particularly preferably 3% by mass or more, most preferably 5% by mass or more, preferably 50% by mass or less, more preferably 45% by mass or less, even more preferably 40% by mass or less, and particularly preferably 20% by mass or less. If the content of component (B) is 0.1% by mass or more, the moldability of the cover composition is further improved, and if it is 50% by mass or less, the decrease in the scratch resistance of the resulting cover can be further suppressed.

[0046] The mass ratio ((A) / (B)) of the (A) thermoplastic polyurethane and the (B) olefin-unsaturated carboxylic acid copolymer and olefin-unsaturated carboxylic acid-unsaturated carboxylic acid ester copolymer in the resin component is preferably 80.0 / 20.0 or higher, more preferably 82.0 / 18.0 or higher, even more preferably 85.0 / 15.0 or higher, preferably 97.0 / 3.0 or lower, more preferably 96.0 / 4.0 or lower, and even more preferably 95.0 / 5.0 or lower. If the mass ratio ((A) / (B)) is 80.0 / 20.0 or higher, the decrease in scratch resistance of the resulting cover can be further suppressed, and if it is 97.0 / 3.0 or lower, the moldability of the cover composition can be further improved.

[0047] (Other resin components) The cover composition may contain only (A) thermoplastic polyurethane, (B) olefin-unsaturated carboxylic acid copolymer and / or olefin-unsaturated carboxylic acid-unsaturated carboxylic acid ester copolymer as resin components, but may also contain other resin components in addition to these.

[0048] Other resin components include thermoplastic elastomers and the like.

[0049] Specific examples of the aforementioned thermoplastic elastomers include, for example, thermoplastic polyamide elastomers such as Arkema's "Pebax® (e.g., "Pebax 2533")", thermoplastic polyester elastomers such as Toray Celanese's "Hytrel® (e.g., "Hytrel 3548", "Hytrel 4047")", and thermoplastic polystyrene elastomers such as Mitsubishi Chemical's "Tefablock®".

[0050] When resin components other than components (A) and (B) are blended as the resin component, the total content of components (A) and (B) in the resin component is preferably 85% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and particularly preferably 99% by mass or more.

[0051] (Additives) The cover composition may further contain additives such as pigment components like titanium dioxide or blue pigment, weight modifiers like calcium carbonate or barium sulfate, dispersants, antioxidants, ultraviolet absorbers, light stabilizers, fluorescent materials, or fluorescent whitening agents, to the extent that they do not impair the cover performance. The content of the resin component in the cover composition is preferably 90% by mass or more, more preferably 92% by mass or more, and even more preferably 94% by mass or more.

[0052] The content of the white pigment (titanium dioxide) is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, even more preferably 1.5 parts by mass or more, preferably 10 parts by mass or less, more preferably 8 parts by mass or less, and even more preferably 6 parts by mass or less, per 100 parts by mass of the resin component. If the content of the white pigment is 0.5 parts by mass or more, the cover can be given opacity, and if it is 10 parts by mass or less, the decrease in the durability of the cover can be suppressed.

[0053] The cover composition preferably does not contain a basic metal compound that neutralizes the carboxyl groups of the (B) olefin-unsaturated carboxylic acid copolymer and / or olefin-unsaturated carboxylic acid-unsaturated carboxylic acid ester copolymer. Examples of metals included in the basic metal compound include lithium, sodium, potassium, calcium, magnesium, zinc, aluminum, nickel, iron, copper, manganese, tin, lead, and cobalt. Examples of the basic metal compound include magnesium oxide, magnesium hydroxide, magnesium carbonate, zinc oxide, sodium hydroxide, sodium carbonate, calcium oxide, calcium hydroxide, lithium hydroxide, lithium carbonate, and magnesium stearate.

[0054] The cover composition can be obtained, for example, by dry blending component (A), component (B), and other additives as needed. Alternatively, the dry-blended mixture may be extruded to form pellets. For dry blending, it is preferable to use a mixer capable of blending pelletized raw materials, and more preferably a tumbler-type mixer. For extrusion, known extruders such as single-screw extruders, twin-screw extruders, and twin-screw single-screw extruders can be used.

[0055] The slab hardness of the cover composition is preferably 80.0 or higher on the Shore A hardness scale, more preferably 85.0 or higher, even more preferably 90.0 or higher, preferably 97.0 or lower, more preferably 96.0 or lower, and even more preferably 95.0 or lower. If the slab hardness is 80.0 or higher on the Shore A hardness scale, the amount of spin in driver shots can be reduced, and if it is 97.0 or lower, the amount of spin in approach shots can be increased.

[0056] The melt viscosity (190°C) of the cover composition is preferably 1100.0 Pa·s or less, more preferably 1070.0 Pa·s or less, and even more preferably 1050.0 Pa·s or less. If the melt viscosity (190°C) is 1100.0 Pa·s or less, the moldability of the cover composition is further improved. There is no particular lower limit to the melt viscosity (190°C), but it is preferably 10 Pa·s or more. The method for measuring the melt viscosity (190°C) will be described later.

[0057] The flow initiation temperature of the cover composition is preferably 173.0°C or lower, more preferably 172.5°C or lower, and even more preferably 172.0°C or lower. If the flow initiation temperature is 173.0°C or lower, the moldability of the cover composition is further improved. The lower limit of the flow initiation temperature is not particularly limited, but it is preferably 70°C or higher. The method for measuring the flow initiation temperature will be described later.

[0058] [Golf balls] The golf ball of the present invention has a spherical core and a cover that covers the spherical core. The cover constitutes the outermost layer of the golf ball body. The present invention relates to the moldability and scratch resistance of the cover, and the structure of the spherical core is not limited.

[0059] (Spherical core) Examples of the spherical core include a single-layer spherical core, a spherical core consisting of a center and one intermediate layer covering the center, and a spherical core consisting of a center and two or more intermediate layers covering the center.

[0060] A known rubber composition (hereinafter sometimes simply referred to as "rubber composition for core") can be used for the spherical core or center. For example, a rubber composition containing a base rubber, a co-crosslinking agent, and a crosslinking initiator can be molded by heating and pressing.

[0061] As the base rubber, it is preferable to use high-cis polybutadiene containing 40% by mass or more, preferably 70% by mass or more, and more preferably 90% by mass or more, cis bonds which are advantageous for rebound.

[0062] The cocrosslinking agent is preferably an α,β-unsaturated carboxylic acid having 3 to 8 carbon atoms or a metal salt thereof, more preferably an acrylic acid or a metal salt thereof, or a methacrylic acid or a metal salt thereof. The metal of the metal salt is preferably zinc, magnesium, calcium, aluminum, or sodium, more preferably zinc. The amount of cocrosslinking agent used is preferably 20 to 50 parts by mass per 100 parts by mass of the base rubber. When using an α,β-unsaturated carboxylic acid having 3 to 8 carbon atoms as the cocrosslinking agent, it is preferable to incorporate a metal compound (e.g., magnesium oxide).

[0063] Organic peroxides are preferably used as crosslinking initiators. Specifically, examples of organic peroxides include dicumyl peroxide, 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, and di-t-butyl peroxide, of which dicumyl peroxide is preferably used. The amount of crosslinking initiator blended is preferably 0.2 parts by mass or more, more preferably 0.3 parts by mass or more, even more preferably 0.4 parts by mass or more, preferably 5 parts by mass or less, more preferably 4 parts by mass or less, and even more preferably 3 parts by mass or less, per 100 parts by mass of base rubber.

[0064] Furthermore, the core rubber composition may also contain an organic sulfur compound. Suitable organic sulfur compounds include diphenyl disulfides, thiophenols, and thionaphthols. The amount of organic sulfur compound is preferably 0.1 parts by mass or more, more preferably 0.3 parts by mass or more, even more preferably 0.5 parts by mass or more, preferably 5.0 parts by mass or less, more preferably 4.0 parts by mass or less, and even more preferably 2.0 parts by mass or less, per 100 parts by mass of the base rubber.

[0065] The core rubber composition may further contain a carboxylic acid and / or its salt. Preferably, the carboxylic acid and / or its salt has 1 to 30 carbon atoms. The carboxylic acid can be either an aliphatic carboxylic acid or an aromatic carboxylic acid (such as benzoic acid). The amount of carboxylic acid and / or its salt added is 1 part by mass or more and 40 parts by mass or less per 100 parts by mass of the base rubber.

[0066] In addition to the base rubber, co-crosslinking agent, crosslinking initiator, and organic sulfur compound, the core rubber composition may also contain, as appropriate, weight adjusters such as zinc oxide and barium sulfate, antioxidants, colorants, and the like.

[0067] The heating and pressing conditions for the core rubber composition can be set appropriately according to the rubber composition, but it is generally preferable to heat at 130°C to 200°C for 10 to 60 minutes, or to heat at 130°C to 150°C for 20 to 40 minutes, followed by two-stage heating at 160°C to 180°C for 5 to 15 minutes.

[0068] When the spherical core has an intermediate layer, examples of intermediate layer materials include thermoplastic resins such as polyurethane resin, ionomer resin, polyamide resin, and polyethylene; thermoplastic elastomers such as styrene elastomer, polyolefin elastomer, polyurethane elastomer, polyamide elastomer, and polyester elastomer; and cured rubber compositions. Here, examples of ionomer resins include those in which at least a portion of the carboxyl groups in a copolymer of ethylene and an α,β-unsaturated carboxylic acid are neutralized with metal ions, or those in which at least a portion of the carboxyl groups in a terpolymer of ethylene, an α,β-unsaturated carboxylic acid, and an α,β-unsaturated carboxylic acid ester are neutralized with metal ions. The intermediate layer may further contain weight adjusters such as barium sulfate and tungsten, antioxidants, pigments, etc.

[0069] The method for forming the intermediate layer is not particularly limited, but examples include a method in which the intermediate layer composition is pre-formed into a hemispherical half-shell, two of these are used to enclose a sphere, and then pressure-molded, or a method in which the intermediate layer composition is directly injection-molded onto a sphere to enclose the sphere.

[0070] When forming an intermediate layer by injection molding an intermediate layer composition onto a sphere, it is preferable to use upper and lower molds having hemispherical cavities. The intermediate layer can be formed by injection molding by extending a holding pin, inserting and holding the coated sphere, injecting the heated and melted intermediate layer composition, and then cooling it.

[0071] When forming an intermediate layer by compression molding, the half-shell can be formed by either compression molding or injection molding, but compression molding is preferred. Conditions for compressing the intermediate layer composition to form a half-shell include, for example, a pressure of 1 MPa or more and 20 MPa or less, and a molding temperature of -20°C or more and +70°C or less relative to the flow start temperature of the intermediate layer composition. By using these molding conditions, a half-shell with a uniform thickness can be formed. As a method for forming an intermediate layer using a half-shell, for example, a method of covering a sphere with two half-shells and compress molding them can be used. Conditions for compressing the half-shell to form an intermediate layer include, for example, a molding pressure of 0.5 MPa or more and 25 MPa or less, and a molding temperature of -20°C or more and +70°C or less relative to the flow start temperature of the intermediate layer composition. By using these molding conditions, an intermediate layer with a uniform thickness can be formed.

[0072] The molding temperature refers to the highest temperature reached by the surface of the recess in the lower mold between mold clamping and mold opening. The flow start temperature of the composition was determined using Shimadzu Corporation's "Flow Tester CFT-500" with a pelletized thermoplastic resin composition and a plunger area of ​​1 cm². 2 Measurements can be taken under the following conditions: DIE LENGTH: 1mm, DIE DIA: 1mm, Load: 588.399N, Starting temperature: 30℃, Heating rate: 3℃ / min.

[0073] The diameter of the spherical core is preferably 34.8 mm or more, more preferably 35.7 mm or more, even more preferably 36.6 mm or more, preferably 42.2 mm or less, more preferably 41.8 mm or less, even more preferably 41.2 mm or less, and most preferably 40.8 mm or less. If the diameter of the spherical core is 34.8 mm or more, the thickness of the cover will not become too thick, and the resilience will be better. On the other hand, if the diameter of the spherical core is 42.2 mm or less, the cover will not become too thin, and the function of the cover will be better performed.

[0074] (The structure of a golf ball) The structure of the golf ball is not particularly limited as long as it has a spherical core and a cover that covers the spherical core. Examples of golf ball structures include a two-piece golf ball having a single-layer spherical core and a cover that covers the spherical core; a three-piece golf ball having a spherical core consisting of a center and one intermediate layer covering the center and a cover that covers the spherical core; and a multi-piece golf ball having a spherical core consisting of a center and two or more intermediate layers covering the center and a cover that covers the spherical core.

[0075] The method of forming the cover using the cover composition is not particularly limited, but examples include directly injection molding the cover composition onto a spherical core, or forming a hollow shell from the cover composition and then compression molding the spherical core with multiple shells (preferably, forming a hollow half-shell from the cover composition and then compression molding the spherical core with two half-shells). From the viewpoint of golf ball productivity, the method of directly injection molding the cover composition onto a spherical core is preferred.

[0076] When the cover composition is directly injection-molded into a spherical core, the molding temperature is preferably 180°C or higher, more preferably 185°C or higher, even more preferably 190°C or higher, preferably 250°C or lower, more preferably 245°C or lower, and even more preferably 240°C or lower. A molding temperature of 180°C or higher further improves the moldability of the cover composition, and a temperature of 250°C or lower further suppresses the decrease in the scratch resistance of the resulting cover.

[0077] The golf ball body, with its molded cover, is removed from the mold and, if necessary, undergoes surface treatment such as deburring, cleaning, and sandblasting. A mark can also be formed as desired.

[0078] The total number of dimples formed on the cover is preferably between 200 and 500. If the total number of dimples is less than 200, the effect of the dimples is difficult to obtain. Also, if the total number of dimples exceeds 500, the size of each dimple becomes smaller, making it difficult to obtain the effect of the dimples. The shape of the formed dimples (planar view shape) is not particularly limited, and may be a circle; a polygon such as a roughly triangular, roughly square, roughly pentagon, roughly hexagon; or other irregular shapes; used individually or in combination of two or more types.

[0079] The golf balls with molded covers are removed from the mold and, if necessary, subjected to surface treatments such as deburring, cleaning, and sandblasting. A coating or mark can also be formed as desired. The thickness of the coating is not particularly limited, but is preferably 5 μm or more, more preferably 7 μm or more, even more preferably 9 μm or more, preferably 50 μm or less, more preferably 40 μm or less, and even more preferably 30 μm or less. A thickness of 5 μm or more ensures that the coating is less likely to wear away even with continuous use, while a thickness of 50 μm or less allows the dimple effect to be fully realized.

[0080] The diameter of the golf ball is preferably 40 mm to 45 mm. From the viewpoint of meeting the standards of the United States Golf Association (USGA), a diameter of 42.67 mm or more is particularly preferred. From the viewpoint of suppressing air resistance, a diameter of 44.00 mm or less is more preferred, and 42.80 mm or less is particularly preferred. The mass of the golf ball is preferably 40 g to 50 g. From the viewpoint of obtaining a large inertia, a mass of 44.00 g or more is more preferred, and 45.00 g or more is particularly preferred. From the viewpoint of meeting the standards of the USGA, a mass of 45.93 g or less is particularly preferred.

[0081] In the golf ball of the present invention, when the diameter is 40 mm to 45 mm, the amount of compression deformation (the amount the golf ball shrinks in the compression direction) when an initial load of 98 N is applied and a final load of 1275 N is applied is preferably 2.0 mm or more, more preferably 2.4 mm or more, even more preferably 2.5 mm or more, preferably 5.0 mm or less, more preferably 4.5 mm or less, and even more preferably 4.0 mm or less. A golf ball with a compression deformation of 2.0 mm or more is not too hard and has a good feel when hit. On the other hand, by making the compression deformation amount 5.0 mm or less, the rebound performance is increased.

[0082] Figure 1 is a partially cutaway cross-sectional view showing a golf ball 1 according to one embodiment of the present invention. The golf ball 1 has a spherical core 2 and a cover 3 disposed on the outside of the spherical core 2. Numerous dimples 31 are formed on the surface of the cover 3. The portion of the surface of the cover 3 other than the dimples 31 is a land 32. The cover 3 is formed from the cover material. [Examples]

[0083] The present invention will be described in detail below with reference to examples, but the present invention is not limited to the following examples, and any modifications and embodiments that do not depart from the spirit of the present invention are all included within the scope of the present invention.

[0084] [Evaluation Method] (1) Slab hardness (Shore A hardness) Using the cover composition, a sheet approximately 2 mm thick was fabricated by injection molding and stored at 23°C for two weeks. Three or more of these sheets were stacked to avoid interference from the measurement substrate, and their hardness was measured using an automated hardness tester (H. Barleys, DigiTest II). The "Shore A" detector was used.

[0085] (2) Fourier transform infrared spectroscopy (FT-IR) measurement The raw materials for the cover composition were kneaded in a twin-screw extruder, extruded, and then cut into pellets to prepare the measurement samples. The sample obtained above was subjected to FT-IR analysis under the following measurement conditions. From the obtained spectrum, the difference Δν(ν1-ν2) between the wavenumber (ν1) of the absorption peak based on NH groups that do not form hydrogen bonds in (A) thermoplastic polyurethane and the wavenumber (ν2) of the absorption peak based on NH groups that form hydrogen bonds with the carbonyl oxygen of the urethane group in (A) thermoplastic polyurethane was determined. <Measurement conditions> Equipment: Fourier transform infrared spectrophotometer (Agilent Technologies, "Cary 670 FTIR"), diamond ATR instrument (Specac, Golden Gate) Measurement method: Single reflection total reflectance measurement method (ATR method) Measurement range: 400cm -1 ~4000cm -1 Resolution: 4cm -1 Total number of times: 32 Crystal: Diamond Heating rate: 10℃ / min Measurement temperature: 190℃

[0086] (3) Melt viscosity The melt viscosity was measured for the pelletized cover composition using a flow characteristics evaluation device (Shimadzu Corporation, Flow Tester CFT-500D) and evaluated according to the following criteria. The measurement conditions were: die length: 10 mm, die bore diameter: 1 mm, cylinder pressure: 3 MPa, temperature: 190 °C. ◎: Less than 900 Pa·s ○: 900 Pa·s or higher, less than 1100 Pa·s △: 1100 Pa·s or higher, less than 1200 Pa·s ×: 1200Pa·s or more

[0087] (4) Flow start temperature The flow initiation temperature was measured for the pelletized cover composition using a flow characteristics evaluation device (Shimadzu Corporation, Flow Tester CFT-500D) and evaluated according to the following criteria. Measurement conditions: Plunger area: 1 cm² 2The dimensions were set to DIELENGTH: 1 mm, load: 588.399 N, starting temperature: 30 °C, and heating rate: 3 °C / min. ◎: Below 168.0℃ ○: 168.0℃ or higher, less than 175.0℃ ×: Above 175.0℃

[0088] (5) Cover thickness After the cover molding process, golf balls were cut perpendicular to the seam line, passing through each pole. The cut balls were then stored at 23°C ± 1°C for at least two hours. Subsequently, the cover thickness was measured at each pole, at two points slightly above the seam, and at two points slightly below the seam. The average of these six thicknesses was used as the cover thickness. The poles are the vertices of the upper and lower hemispheres when the golf ball is divided in half vertically along the seam line.

[0089] (6) Formability After the cover molding process, golf balls were cut perpendicular to the seam line, passing through each pole, to evaluate the moldability of the cover. Specifically, the cut balls were stored at 23°C ± 1°C for at least two hours. Then, the cover thickness at each pole was measured on the cut surface, and the difference (d1) was calculated. The cover thickness at two points slightly above the seam was measured, and the difference (d2) was calculated. The cover thickness at two points slightly below the seam was measured, and the difference (d3) was calculated. The largest of these differences (d1), (d2), and (d3) was taken as the thickness variation value. Based on the thickness variation value, the balls were evaluated according to the following criteria. ◎: Well-formed (wall thickness variation of 0.1 mm or less). ○: The molding is successful, but there is some unevenness in thickness (0.1mm to 0.4mm). △: The molding is done, but there is significant wall thickness variation (wall thickness variation of 0.4 mm or more). ×: Not molded.

[0090] (7) Scratch resistance A commercially available pitching wedge was attached to a swing robot and struck two different spots on a golf ball at a head speed of 36 m / s. The two impact points were visually observed and evaluated on a 5-point scale based on the following criteria, with the worse of the two being used as the final evaluation result. If a cover of the specified thickness could not be molded and scratch resistance could not be evaluated, it was marked with "×". 5 points; virtually no damage is noticeable. 4 points; No visible damage was observed, but slight scratches were found upon close inspection. 3 points; There are visible scratches. Two points; there are noticeable scratches. 1 point; has damage that makes it unusable.

[0091] [Golf ball manufacturing] (1) Preparation of rubber composition The raw materials were kneaded using a kneading roll to obtain the rubber composition shown in Table 1.

[0092] [Table 1]

[0093] The materials used in Table 1 are as follows: BR730: Manufactured by JSR, high-cis polybutadiene rubber (cis-1,4-bond content = 95% by mass, 1,2-vinyl bond content = 1.3% by mass, Mooney viscosity (ML) 1+4 (100℃)=55, molecular weight distribution (Mw / Mn)=3) ZN-DA90S: Manufactured by Nichishoku Techno Fine Chemicals, zinc acrylate (containing 10% zinc stearate) Zinc oxide: Manufactured by Toho Zinc, "Ginrei R" Barium sulfate: Sakai Chemical Co., Ltd., "Barium Sulfate BD" Dicumyl peroxide: Manufactured by Tokyo Chemical Industry Co., Ltd.

[0094] (2) Preparation of the cover composition The raw materials were extruded using a twin-screw kneading extruder to prepare pelletized cover compositions according to the formulations shown in Table 2. The evaluation results for the obtained cover compositions are shown in Table 2. The IR spectra of cover compositions No. 1, 4, and 6 are shown in Figure 2.

[0095] [Table 2]

[0096] The materials used in Table 2 are as follows: Elastoran (registered trademark) 1195ATR: Manufactured by BASF Japan, thermoplastic polyurethane elastomer (polyisocyanate is 4,4'-dicyclohexylmethane diisocyanate) (slab hardness (Shore A) 95) Titanium dioxide: Manufactured by Ishihara Sangyo, A-220

[0097] As shown in Table 2, the smaller the Δν of the resin component, the more the hydrogen bonds are relaxed, the lower the melt viscosity, and the lower the flow initiation temperature. Therefore, the smaller the Δν of the resin component, the higher the fluidity of the cover, making it possible to mold thinner covers even with injection molding, and the lower the flow initiation temperature, allowing the molding temperature to be set lower.

[0098] (3) Formation of the cover The cover composition was injection-molded onto a spherical core to obtain a golf ball. The spherical core was placed into a final mold having numerous pimples on the cavity surface. The cover composition was injection molded into a spherical core shape to obtain a golf ball in which numerous dimples were formed on the cover, with the shape of the pimples on the cavity surface being inverted. The results of the evaluation of the obtained golf ball are shown in Tables 3 and 4.

[0099] [Table 3]

[0100] The golf balls No. 1-7 shown in Table 3 have a cover thickness of 1.6 mm and the cover is molded at a temperature of 230°C. Golf balls No. 1-4 have a cover with a resin component Δν of 100.0 cm². -1 ~109.0cm -1 These golf balls No. 1 to 4 are formed from cover compositions No. 3 to 6. The covers of these golf balls No. 1 to 4 had good moldability and excellent scratch resistance. Golf balls No. 5 and 6 have a cover with a resin component Δν of 109.0 cm². -1 These golf balls are formed from the superior cover composition No. 1 or 2. While these golf balls exhibit excellent scratch resistance in the formed cover, the moldability of the cover was inferior compared to golf balls No. 1-4. Golf ball No. 7 has a cover with a resin component Δν of 100.0 cm -1 It is formed from cover composition No. 7, which is less than [amount missing]. This golf ball No. 7 has good moldability for the cover, but the scratch resistance of the formed cover is poor.

[0101] [Table 4]

[0102] The golf balls No. 8-11 shown in Table 4 have a cover thickness of 1.4 mm and the cover is molded at a temperature of 230°C. Golf balls No. 8 and 9 have a cover with a resin component Δν of 100.0 cm². -1 ~109.0cm -1 These golf balls, No. 8 and 9, are formed from cover compositions No. 3 and 4. Even with a thin cover thickness of 1.4 mm, the covers of these golf balls No. 8 and 9 could be molded at a molding temperature of 230°C, and the covers also exhibited excellent scratch resistance. Golf balls No. 10 and 11 have a cover with a resin component Δν of 109.0 cm². -1These golf balls are formed from either cover composition No. 1 or 2. At a molding temperature of 230°C, these golf balls were unable to form a cover.

[0103] The golf balls No. 12-14 shown in Table 4 have a cover thickness of 1.4 mm and the cover was molded at a temperature of 250°C. Golf balls No. 12-14 were able to form a 1.4mm cover at a molding temperature of 250°C, but golf balls No. 13 and 14 showed significantly reduced scratch resistance to the cover. Golf ball No. 12 had superior scratch resistance compared to golf balls No. 13 and 14.

[0104] The present invention (1) is a golf ball having a spherical core and a cover covering the spherical core, wherein the cover contains (A) thermoplastic polyurethane as a resin component, and when the cover is measured with a Fourier transform infrared spectrophotometer under the following measurement conditions, the difference Δν(ν1-ν2) between the wavenumber (ν1) of the absorption peak based on NH groups of the (A) thermoplastic polyurethane that do not form hydrogen bonds and the wavenumber (ν2) of the absorption peak based on NH groups that form hydrogen bonds with the carbonyl oxygen of the urethane group of the (A) thermoplastic polyurethane is 100.0 cm². -1 ~109.0cm -1 This golf ball is characterized by the following: <Measurement conditions> Measurement method: Single-reflection ATR (Attenuated Total Reflection) method Measurement range: 400cm -1 ~4000cm -1 Resolution: 4cm -1 Total number of times: 32 Crystal: Diamond Heating rate: 10℃ / min Measurement temperature: 190℃

[0105] The present invention (2) is a golf ball according to the present invention (1), wherein the cover is formed from a cover composition containing, as a resin component, (A) thermoplastic polyurethane and (B) olefin-unsaturated carboxylic acid copolymer and / or olefin-unsaturated carboxylic acid-unsaturated carboxylic acid ester copolymer.

[0106] The present invention (3) is a golf ball according to the present invention (2), wherein the mass ratio ((A) / (B)) of the resin component (A) thermoplastic polyurethane and (B) olefin-unsaturated carboxylic acid copolymer and olefin-unsaturated carboxylic acid-unsaturated carboxylic acid ester copolymer is 80.0 / 20.0 to 97.0 / 3.0.

[0107] The present invention (4) is a golf ball according to any one of the present inventions (1) to (3), wherein the thermoplastic polyurethane (A) contains an alicyclic diisocyanate and / or an aromatic diisocyanate as the polyisocyanate constituting the thermoplastic polyurethane (A).

[0108] The present invention (5) is a golf ball according to the present invention (4), wherein the polyisocyanate is at least one diisocyanate selected from the group consisting of 4,4'-dicyclohexylmethane diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, isophorone diisocyanate, trans-1,4-cyclohexane diisocyanate, 4,4'-diphenylmethane diisocyanate, and toluene diisocyanate. [Explanation of Symbols]

[0109] 1: Golf ball, 2: Spherical core, 3: Cover, 31: Dimple, 32: Land

Claims

1. A golf ball having a spherical core and a cover that covers the spherical core, The cover contains (A) thermoplastic polyurethane as a resin component, When the aforementioned cover was measured with a Fourier transform infrared spectrophotometer under the following measurement conditions, The difference Δν(ν1-ν2) between the wavenumber (ν1) of the absorption peak based on the N-H group that does not form a hydrogen bond in the thermoplastic polyurethane (A) and the wavenumber (ν2) of the absorption peak based on the N-H group that forms a hydrogen bond with the carbonyl oxygen of the urethane group in the thermoplastic polyurethane (A) is 100.0 cm. -1 ~109.0cm -1 A golf ball characterized by the following: <Measurement conditions> Measurement method: Single-reflection ATR (Attenuated Total Reflection) method Measurement range: 400 cm -1 ~4000 -1 Decomposition energy: 4 cm -1 Total number of times: 32 Crystal: Diamond Heating rate: 10°C / min Measurement temperature: 190℃

2. The golf ball according to claim 1, wherein the cover is formed from a cover composition containing (A) thermoplastic polyurethane and (B) an olefin-unsaturated carboxylic acid copolymer and / or an olefin-unsaturated carboxylic acid-unsaturated carboxylic acid ester copolymer as resin components.

3. The golf ball according to claim 2, wherein the mass ratio ((A) / (B)) of the resin component between (A) thermoplastic polyurethane and (B) olefin-unsaturated carboxylic acid copolymer and olefin-unsaturated carboxylic acid-unsaturated carboxylic acid ester copolymer is 80.0 / 20.0 to 97.0 / 3.

0.

4. The golf ball according to claim 1, wherein the thermoplastic polyurethane (A) contains an alicyclic diisocyanate and / or an aromatic diisocyanate as the polyisocyanate constituting the thermoplastic polyurethane (A).

5. The golf ball according to claim 4, wherein the polyisocyanate is at least one diisocyanate selected from the group consisting of 4,4'-dicyclohexylmethane diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, isophorone diisocyanate, trans-1,4-cyclohexane diisocyanate, 4,4'-diphenylmethane diisocyanate, and toluene diisocyanate.

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