JP2020179065A - Golf ball - Google Patents

Abstract

To provide a golf ball that is excellent in carry when being shot by a driver in rainy weather and spin performance at approach shot.SOLUTION: A golf ball includes: a golf ball body; and at least one layer of coating film that coats the golf ball body. An outermost layer coating film is formed of a coating material including a polyol compound, a polyisocyanate compound and a silicone compound. A surface of the outermost layer coating film has a water sliding angle of 50° or less. The surface of the outermost layer coating film has a dynamic friction coefficient of 0.3 to 0.9.SELECTED DRAWING: None

Description

The present invention relates to a golf ball having a coating film.

Conventionally, in a golf ball, a coating film is formed on the surface of the golf ball body. This coating film contributes to the performance, quality, appearance, etc. of the golf ball. It has been proposed to impart water repellency to such a coating film to prevent water from adhering to the surface of a golf ball when used in rainy weather or the like.

For example, Patent Document 1 describes a core, a cover provided outside the core and formed with dimples, and a material provided outside the cover and having a contact angle of 90 ° or more. A golf ball having an outer surface layer and having a dynamic friction coefficient of 0.52 or more of the golf ball is described (see Patent Document 1 (Claim 1, 0042)).

Further, in Patent Document 2, a core, a cover provided on the outside of the core and formed with dimples, and a cover provided on the outside of the cover, the contact angle is 90 ° or more, and the dynamic contact angle is 85. A golf ball with an outer surface layer formed of a material of ° or less is described, although it is described (see Patent Document 2 (Claim 1, 0041, 0042)).

JP-A-2019-10190 Japanese Unexamined Patent Publication No. 2019-10191

Conventionally, it has been proposed to increase the water repellency of the surface of a golf ball, but such a golf ball tends to reduce the spin performance in an approach shot. The present invention has been made in view of the above circumstances, and by controlling the coating film composition, a golf ball having improved flight distance on driver shots such as in rainy weather while maintaining spin performance on approach shots. The purpose is to provide.

The golf ball of the present invention that has been able to solve the above problems has a golf ball body and at least one coating film that covers the golf ball body, and the outermost layer of the coating film is a polyol compound or poly. It is formed from a coating material containing an isocyanate compound and a silicone compound, the water sliding angle of the surface of the outermost layer coating film is less than 50 °, and the dynamic friction coefficient of the surface of the outermost layer coating film is 0.3 to It is characterized by being 0.9.

The outermost layer of the coating film is formed of a paint containing a polyol compound, a polyisocyanate compound, and a silicone compound, and the outermost layer coating film has a predetermined water sliding angle, so that the outermost layer coating film has water repellency. Is improved, and the flight distance of driver shots in rainy weather is improved. Further, since the outermost coating film has a predetermined dynamic friction coefficient, the spin performance in the approach shot is also improved.

According to the present invention, a golf ball having excellent flight distance on driver shots such as in rainy weather and spin performance on approach shots can be obtained.

A partially cutaway sectional view showing a golf ball according to an embodiment of the present invention.

The golf ball of the present invention has a golf ball body and at least one layer of a coating film that covers the golf ball body. The outermost layer of the coating film is formed of a coating material containing a polyol compound, a polyisocyanate compound, and a silicone compound (hereinafter, may be referred to as "painting for the outermost layer"), and the outermost layer coating film. The water sliding angle of the surface of the outermost layer coating film is less than 50 °, and the dynamic friction coefficient of the surface of the outermost layer coating film is 0.3 to 0.9. Since the outermost layer coating film has a predetermined water sliding angle, the water repellency of the outermost layer coating film is improved, water is less likely to adhere to the golf ball surface in rainy weather, and the golf ball surface. Even in the presence of water, the surface water can be quickly blown off by hitting. Therefore, the flight distance of the driver shot in rainy weather is improved. Further, since the outermost coating film has a predetermined dynamic friction coefficient, the spin performance in the approach shot is also improved.

(Coating film)
The coating film may have a single-layer structure or a multi-layer structure. In the coating film, the outermost layer coating film located on the outermost layer of the golf ball is formed from the outermost layer paint, and has a predetermined water sliding angle and dynamic friction coefficient. When the coating film has a single-layer structure, the single-layer coating film is formed from the outermost layer coating material and has a predetermined water sliding angle and dynamic friction coefficient. When the coating film has a multi-layer structure, at least the outermost layer coating film is formed from the outermost layer coating film, and has a predetermined water sliding angle and dynamic friction coefficient.

(Physical properties of the outermost coating film)
The water sliding angle of the surface of the outermost layer of the coating film is preferably 5 ° or more, more preferably 8 ° or more, further preferably 10 ° or more, preferably less than 50 °, more preferably 45 ° or less, and further. It is preferably 40 ° or less. If the sliding angle is 5 ° or more, the spin performance in the approach shot is further improved, and if it is less than 50 °, the flight distance of the driver shot in rainy weather or the like is further improved.

The coefficient of kinetic friction of the outermost layer of the coating film is preferably 0.3 or more, more preferably 0.35 or more, further preferably 0.4 or more, preferably 0.9 or less, and more preferably 0.8 or less. , More preferably 0.8 or less. If the coefficient of kinetic friction is 0.3 or more, the spin performance on approach shots is further improved, and if it is 0.9 or less, the flight distance on driver shots is further improved.

The water contact angle on the surface of the outermost layer coating film is preferably 75 ° or more, preferably 80 ° or more. When the water contact angle is 75 ° or more, the flight distance performance of a driver shot in rainy weather is excellent. The upper limit of the water contact angle is not particularly limited, but 120 ° is preferable. From the viewpoint of stability of flight performance, it is preferable that the outermost layer of the golf ball coating film does not include a surface having a water contact angle of less than 70 °. That is, the outermost layer coating film of the golf ball preferably has a water contact angle of 70 ° or more at all positions.

The physical properties of the outermost layer coating film may be evaluated using a coating film formed on the baking coating plate. The method of forming a coating film on the baking coating plate will be described later. The water sliding angle of the coating film on the baking sheet is preferably 2 ° or more, more preferably 4 ° or more, still more preferably 6 ° or more, preferably 50 ° or less, more preferably 45 ° or less, still more preferable. Is 40 ° or less. The water contact angle of the coating film on the baking sheet is preferably 100 ° or more, and preferably 120 ° or less. The water sliding angle of the baking sheet before forming the coating film is more than 60 °, and the water contact angle is 95 °.

The thickness of the outermost layer of the coating film is preferably 2 μm or more, more preferably 4 μm or more, further preferably 6 μm or more, preferably 30 μm or less, more preferably 25 μm or less, still more preferably 20 μm or less. When the thickness of the outermost layer of the coating film is 2 μm or more, the spin performance in the approach shot is further improved, and when it is 30 μm or less, the increase in the spin amount in the driver shot can be suppressed.

(Paint for outermost layer)
The outermost layer coating material contains a polyol compound, a polyisocyanate compound, and a silicone compound. Examples of the outermost layer coating material include a so-called two-component curing urethane coating material containing a polyol composition containing a polyol compound as a main component and a polyisocyanate composition containing a polyisocyanate compound as a curing agent. The silicone compound may be blended in either the polyol composition or the polyisocyanate composition.

(Polyform composition)
The polyol composition contains a polyol compound. Examples of the polyol compound include compounds having two or more hydroxy groups in the molecule. Examples of the polyol compound include a compound having a hydroxy group at the end of the molecule and a compound having a hydroxy group other than the end of the molecule. The polyol compound may be used alone or in combination of two or more. The polyol compound contained in the polyol composition preferably does not have a polysiloxane structure. The carbinol-modified silicone oil described later is not included in the polyol compound.

Examples of the compound having a hydroxy group at the end of the molecule include a low molecular weight polyol having a molecular weight of less than 500 and a high molecular weight polyol having a number average molecular weight of 500 or more. Examples of the low molecular weight polyol include diols such as ethylene glycol, diethylene glycol, triethylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, and 1,6-hexanediol; glycerin and trimethylol. Triols such as propane and hexanetriol can be mentioned. Examples of the high molecular weight polyol include polyether polyol, polyester polyol, polycaprolactone polyol, polycarbonate polyol, urethane polyol, acrylic polyol and the like. Examples of the polyether polyol include polyoxyethylene glycol (PEG), polyoxypropylene glycol (PPG), and polyoxytetramethylene glycol (PTMG). Examples of the polyester polyol include polyethylene adipate (PEA), polybutylene adipate (PBA), polyhexamethylene adipate (PHMA) and the like. Examples of the polycaprolactone polyol include poly-ε-caprolactone (PCL). Examples of the polycarbonate polyol include polyhexamethylene carbonate and the like.

The urethane polyol is a compound having a plurality of urethane bonds in the molecule and having two or more hydroxy groups in one molecule. As the urethane polyol, for example, the first polyol component and the first polyisocyanate component are reacted under the condition that the hydroxy group of the first polyol component is excessive with the isocyanate group of the first polyisocyanate component. The urethane prepolymer to be used can be mentioned.

Examples of the first polyol component of the urethane polyol include polyether diol, polyester diol, polycaprolactone diol, polycarbonate diol and the like, and polyether diol is preferable. Examples of the polyether diol include polyoxyethylene glycol, polyoxypropylene glycol, polyoxytetramethylene glycol and the like, and among these, polyoxytetramethylene glycol is preferable.

The number average molecular weight of the polyether diol is preferably 500 or more, more preferably 600 or more, preferably 4,000 or less, more preferably 3,000 or less, still more preferably 3,000 or less. When the number average molecular weight of the polyether diol is 500 or more, the distance between the cross-linking points in the coating film becomes long and the coating film becomes soft, so that the spin performance is improved. When the number average molecular weight is 4,000 or less, the distance between the cross-linking points in the coating film is not too long, and the stain resistance of the coating film is good. The number average molecular weight of the polyol component is determined by, for example, gel permeation chromatography (GPC) using polystyrene as a standard substance, tetrahydrofuran as an eluent, and an organic solvent-based GPC column as a column (for example, "Shodex" manufactured by Showa Denko Co., Ltd. It may be measured using (trademark) KF series, etc.).

The first polyol component may contain a low molecular weight polyol having a molecular weight of less than 500. Examples of the low molecular weight polyol include diols such as ethylene glycol, diethylene glycol, triethylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, and 1,6-hexanediol; glycerin and trimethylol. Triols such as propane and hexanetriol can be mentioned. The low molecular weight polyol may be used alone or in combination of two or more.

The urethane polyol preferably contains a triol component and a diol component as the first polyol component. As the triol component, trimethylolpropane is preferable. The mixing ratio of the triol component and the diol component (triol component / diol component) is preferably 0.2 or more, more preferably 0.5 or more, preferably 6.0 or less, and more preferably 5.0 or less in terms of mass ratio. preferable.

The first polyisocyanate component that can constitute the urethane polyol is not particularly limited as long as it has two or more isocyanate groups, and is, for example, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 2,4-. Mixture of toluene diisocyanate and 2,6-toluene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate (MDI), 1,5-naphthylene diisocyanate (NDI), 3,3'-bitrylene-4,4'-diisocyanate Aromatic polyisocyanates such as (TODI), xylylene diisocyanate (XDI), tetramethylxylylene diisocyanate (TMXDI), paraphenylene diisocyanate (PPDI); 4,4'-dicyclohexylmethane diisocyanate (H ₁₂ MDI), hydrogenated xyl Examples thereof include alicyclic polyisocyanates such as range isocyanate (H ₆ XDI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), norbornene diisocyanate (NBDI) or aliphatic polyisocyanates. These polyisocyanates may be used alone or in combination of two or more.

The urethane polyol has a content of the polyether diol of preferably 30% by mass or more, more preferably 35% by mass or more, still more preferably 40% by mass or more. The polyether diol forms soft segments in the coating film. Therefore, when the content of the polyether diol is 30% by mass or more, the spin performance of the obtained golf ball is further improved.

The urethane polyol preferably has a weight average molecular weight of 5,000 or more, more preferably 5,300 or more, still more preferably 5,500 or more, preferably 20,000 or less, and more preferably 18,000 or less. More preferably, it is 16,000 or less. When the weight average molecular weight of the urethane polyol is 5,000 or more, the distance between the cross-linking points in the coating film becomes long and the coating film becomes soft, so that the spin performance is improved. When the weight average molecular weight is 20,000 or less, the distance between the cross-linking points in the coating film is not too long, and the stain resistance of the coating film is good.

The hydroxyl value of the urethane polyol is preferably 10 mgKOH / g or more, more preferably 15 mgKOH / g or more, still more preferably 20 mgKOH / g or more, preferably 200 mgKOH / g or less, more preferably 190 mgKOH / g or less, still more preferably. Is 180 mgKOH / g or less. The hydroxyl value can be measured according to JIS K 1557-1, for example, by an acetylation method.

Examples of the compound having a hydroxy group other than the terminal of the molecule include polyrotaxane having a hydroxy group, a hydroxy group-modified vinyl chloride / vinyl acetate copolymer, and the like.

The hydroxy group-bearing polyrotaxane has a cyclic molecule having at least one hydroxy group and a linear molecule that fits within the ring of the cyclic molecule and holds the cyclic molecule slidably and rotatably. In the polyrotaxane, the linear molecule has a blocking group at both ends thereof, and elimination of the cyclic molecule is prevented. The polyrotaxane does not contain a pseudo-rotaxane in which a cyclic molecule can be eliminated from a linear molecule.

The polyrotaxan having a hydroxy group is arranged at both ends of cyclodextrin, a linear molecule inserted into the cyclic structure of the cyclodextrin, and the linear molecule, and is a seal that prevents the cyclic molecule from detaching. It is preferable to have a group. Polyrotaxan has viscoelasticity because cyclodextrin molecules that are skewered through linear molecules can move along the linear molecules (pulley effect), and even if tension is applied, this pulley effect Since the tension can be uniformly dispersed, unlike the conventional crosslinked polymer, it has an excellent property that cracks and scratches are extremely unlikely to occur.

The cyclodextrin is a general term for oligosaccharides having a cyclic structure. Cyclodextrin is, for example, 6 to 8 D-glucopyranose residues linked cyclically by α-1,4-glucoside bonds. Examples of cyclodextrin include α-cyclodextrin (glucose number: 6), β-cyclodextrin (glucose number: 7), γ-cyclodextrin (glucose number: 8), and α-cyclodextrin. preferable. The cyclodextrin may be used alone or in combination of two or more.

The linear molecule is not particularly limited as long as it is a linear molecule that holds the cyclic structure of cyclodextrin in a skewered manner so as to be slidable and rotatable. Examples of the linear molecule include polyalkylene, polyester, polyether, polyacrylic, and the like. Among these, polyether is preferable, and polyethylene glycol is particularly preferable. Polyethylene glycol has less steric hindrance and can hold the cyclic structure of cyclodextrin in a skewered manner.

The weight average molecular weight of the linear molecule is preferably 5,000 or more, more preferably 6,000 or more, preferably 100,000 or less, and more preferably 80,000 or less.

The linear molecule preferably has functional groups at both ends thereof. By having a functional group, it can be easily reacted with the blocking group. Examples of the functional group include a hydroxy group, a carboxy group, an amino group, a thiol group and the like.

The blocking group is not particularly limited as long as it is arranged at both ends of the linear molecule and can prevent cyclodextrin from being eliminated from the linear molecule. Examples of the method of preventing desorption include a method of physically preventing desorption using a bulky sequestering group and a method of electrostatically preventing desorption using an ionic sequestering group. Examples of the bulky blocking group include a cyclodextrin and an adamantyl group. The number (retention amount) of cyclodextrin retained in the linear molecule is preferably 0.06 to 0.61 and more preferably 0.11 to 0.48, assuming that the maximum retention amount is 1. 24 to 0.41 is more preferable. If it is less than 0.06, the pulley effect may not be exhibited, and if it exceeds 0.61, cyclodextrin may be too densely arranged and the mobility of cyclodextrin may be reduced.

As the polyrotaxane, it is preferable that at least a part of the hydroxy group of cyclodextrin is modified by a caprolactone chain. By caplactone denaturation, the steric hindrance between polyrotaxane and polyisocyanate is alleviated, and the reaction efficiency with polyisocyanate is increased.

As the modification, for example, the hydroxy group of cyclodextrin is treated with propylene oxide to form hydroxypropylation. Subsequently, ε-caprolactone is added to carry out ring-opening polymerization. This modification, on the outside of the ring structure of cyclodextrin, polycaprolactone chain _{- (CO (CH 2) 5} O) nH (n is a natural number of 1 to 100) is a -O-C ₃ H ₆ -O- groups Join through. n represents the degree of polymerization, and is preferably a natural number of 1 to 100, more preferably 2 to 70, and even more preferably 3 to 40. A hydroxy group is formed at the other end of the caprolactone chain by ring-opening polymerization. The terminal hydroxy group of the caprolactone chain can react with polyisocyanate.

The ratio of the hydroxy group modified by the caprolactone chain to the total hydroxy group (100 mol%) of the cyclodextrin before modification is preferably 2 mol% or more, more preferably 5 mol% or more, and 10 mol% or more. Is even more preferable. When the proportion of the hydroxy group modified by the caprolactone chain is within the above range, the hydrophobicity of polyrotaxane becomes high and the reactivity with polyisocyanate becomes high.

The hydroxyl value of the polyrotaxane is preferably 10 mgKOH / g or more, more preferably 15 mgKOH / g or more, still more preferably 20 mgKOH / g or more, preferably 400 mgKOH / g or less, more preferably 300 mgKOH / g or less, still more preferably. It is 220 mgKOH / g or less, particularly preferably 180 mgKOH / g or less. When the hydroxyl value of polyrotaxane is within the above range, the reactivity with polyisocyanate becomes high and the durability of the coating film becomes good.

The total molecular weight of the polyrotaxane is preferably 30,000 or more, more preferably 40,000 or more, further preferably 50,000 or more, preferably 3,000,000 or less, and more preferably 2 in terms of weight average molecular weight. , 500,000 or less, more preferably 2,000,000 or less. If the weight average molecular weight is 30,000 or more, the coating film has sufficient strength, and if it is 3,000,000 or less, the coating film has sufficient softness, and the approach performance of the golf ball is improved. .. The weight average molecular weight of polyrotaxane is determined by, for example, gel permeation chromatography (GPC) using polystyrene as a standard substance, tetrahydrofuran as an eluent, and an organic solvent-based GPC column as a column (for example, "Shodex (registered trademark) manufactured by Showa Denko Co., Ltd." ) KF series, etc.) may be used for measurement.

Specific examples of polycaprolactone modified with polycaprolactone include SELM superpolymers SH3400P, SH2400P, and SH1310P manufactured by Advanced Soft Materials.

The hydroxy group-modified vinyl chloride / vinyl acetate copolymer can adjust the adhesiveness while maintaining the scratch resistance of the coating film. The hydroxy group-modified vinyl chloride / vinyl acetate copolymer is, for example, a method for copolymerizing vinyl chloride, vinyl acetate and a monomer having a hydroxy group (for example, polyvinyl alcohol, hydroxyalkyl acrylate), vinyl chloride / vinyl acetate. It is obtained by a method of partially or completely saponifying the copolymer.

In the hydroxy group-modified vinyl chloride / vinyl acetate copolymer, the content of the vinyl chloride component is preferably 1% by mass or more, more preferably 20% by mass or more, further preferably 50% by mass or more, and 99% by mass or less. It is preferably 95% by mass or less, more preferably 95% by mass or less. Specific examples of the hydroxy group-modified vinyl chloride / vinyl acetate copolymer include Solvine (registered trademark) A, Solvine AL, and Solvine TA3 manufactured by Nisshin Chemical Industry Co., Ltd.

The polyol composition contains a urethane polyol as a polyol compound (aspect 1); as a polyol compound, a cyclodextrin, a linear molecule inserted into the cyclic structure of the cyclodextrin, and the linear molecule. disposed on both ends of a polyrotaxane having a blocking group to prevent desorption of the cyclodextrin, at least a part of hydroxy groups of the cyclodextrin, via a -O-C ₃ H ₆ -O- groups Therefore, an embodiment (Aspect 2) containing a polyrotaxane modified with a caprolactone chain is preferable.

In the polyol composition of the first aspect, the content of the urethane polyol in the polyol compound contained in the polyol composition is preferably 60% by mass or more, more preferably 70% by mass or more, still more preferably 80% by mass or more. Is. It is also preferable that the polyol composition of the first aspect contains only the urethane polyol as the polyol compound.

In the polyol composition of the second aspect, the content of polyrotaxane in the polyol compound contained in the polyol composition is preferably 10% by mass or more, more preferably 15% by mass or more, further preferably 20% by mass or more, 100% by mass. It is preferably mass% or less, more preferably 90% by mass or less, still more preferably 85% by mass or less.

The polyol composition of the second aspect preferably contains polycaprolactone polyol as the polyol compound. The mass ratio of the polycaprolactone to the polycaprolactone polyol (polycaprolactone polyol / polyrotaxane) is preferably 0/100 or more, more preferably 5/95 or more, still more preferably 10/90 or more, and preferably 90/10 or less. , More preferably 85/15 or less, still more preferably 80/20 or less.

The polyol composition of the second aspect preferably contains the hydroxy group-modified vinyl chloride / vinyl acetate copolymer as the polyol compound. The content of the hydroxy group-modified vinyl chloride / vinyl acetate copolymer in the polyol compound contained in the polyol composition is preferably 4% by mass or more, more preferably 8% by mass or more, preferably 50% by mass or less, and 45% by mass. More preferably, it is by mass or less.

(Polyisocyanate composition)
Next, the polyisocyanate composition will be described. The polyisocyanate composition contains a polyisocyanate compound. Examples of the polyisocyanate compound include compounds having two or more isocyanate groups.

Examples of the polyisocyanate compound include 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, a mixture of 2,4-toluene diisocyanate and 2,6-toluene diisocyanate (TDI), and 4,4'-diphenylmethane diisocyanate ( MDI), 1,5-naphthylene diisocyanate (NDI), 3,3'-bitrylene-4,4'-diisocyanate (TODI), xylylene diisocyanate (XDI), tetramethylxylylene diisocyanate (TMXDI), paraphenylenedi isocyanate Aromatic diisocyanates such as (PPDI); 4,4'-dicyclohexylmethane diisocyanate (H ₁₂ MDI), hydrogenated xylylene diisocyanate (H ₆ XDI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), norbornene diisocyanate ( Alicyclic diisocyanates such as NBDI) or aliphatic diisocyanates; and triisocyanates such as alohanates, biuret, isocyanurates, and adducts of these diisocyanates; can be mentioned. The polyisocyanate may be used alone or in combination of two or more.

The alohanate form is, for example, a triisocyanate obtained by further reacting a diisocyanate with a urethane bond formed by reacting a diisocyanate with a low molecular weight diol. The adduct is a triisocyanate obtained by reacting diisocyanate with a low molecular weight triol such as trimethylolpropane or glycerin. The biuret body is, for example, a triisocyanate having a biuret bond represented by the following formula (11). The isocyanurate form of diisocyanate is, for example, a triisocyanate represented by the following formula (12).

式（１１）、（１２）中、Ｒは、ジイソシアネートからイソシアネート基を除いた残基を表わす。

In formulas (11) and (12), R represents a residue obtained by removing an isocyanate group from diisocyanate.

As the triisocyanate, an isocyanurate form of hexamethylene diisocyanate, a biuret form of hexamethylene diisocyanate, and an isocyanurate form of isophorone diisocyanate are preferable.

In the present invention, the polyisocyanate composition preferably contains a triisocyanate compound. The content of the triisocyanate compound in the polyisocyanate contained in the polyisocyanate composition is preferably 50% by mass or more, more preferably 60% by mass or more, still more preferably 70% by mass or more. The polyisocyanate composition most preferably contains only a triisocyanate compound as the polyisocyanate compound.

The isocyanate group content (NCO%) of the polyisocyanate contained in the polyisocyanate composition is preferably 0.5% by mass or more, more preferably 1% by mass or more, further preferably 2% by mass or more, and 45% by mass or less. Preferably, 40% by mass or less is more preferable, and 35% by mass or less is further preferable. The isocyanate group amount (NCO%) of the polyisocyanate can be expressed as 100 × [number of moles of isocyanate groups in the polyisocyanate × 42 (molecular weight of NCO)] / total mass (g) of the polyisocyanate.

Specific examples of the polyisocyanate include DIC's Barnock D-800, Barnock DN-950, Barnock DN-955, Sumika Bayer Urethane's Death Module N75MPA / X, Death Module N3300, and Death Module L75 (C). Sumijour E21-1, Coronate HX manufactured by Nippon Polyurethane Industry Co., Ltd., Coronate HK, Duranate 24A-100 manufactured by Asahi Kasei Chemicals Co., Ltd., Duranate 21S-75E, Duranate TPA-100, Duranate TKA-100, VESTANAT T1890 manufactured by Degussa, etc. Can be done.

The molar ratio (NCO group / OH group) of the hydroxy group (OH group) contained in the polyol composition and the isocyanate group (NCO group) contained in the polyisocyanate composition is preferably 0.1 or more, more preferably 0.2 or more. preferable. If the molar ratio (NCO group / OH group) is less than 0.1, the curing reaction will be insufficient. Further, if the molar ratio (NCO group / OH group) becomes too large, the amount of isocyanate groups becomes excessive, and the obtained coating film becomes hard and brittle, and the appearance is also deteriorated. Therefore, the molar ratio (NCO group / OH group) is preferably 1.5 or less, more preferably 1.4 or less, and even more preferably 1.3 or less. The reason why the appearance of the obtained coating film deteriorates when the amount of isocyanate groups in the paint is excessive is that when the amount of isocyanate groups is excessive, the reaction between the moisture in the air and the isocyanate groups increases and the amount of carbon dioxide gas increases. It is thought that this is because it occurs in.

When the polyol composition of Aspect 1 is used as the polyol composition, the polyisocyanurate composition is composed of a biuret-modified hexamethylene diisocyanate, an isocyanurate-modified hexamethylene diisocyanate, and an isophorone diisocyanurate as the polyisocyanate compound. It preferably contains a modified isocyanurate. When the biuret-modified product of hexamethylene diisocyanate and the isocyanurate-modified product are used in combination, the mixing ratio of these (biuret-modified product / isocyanurate-modified product) is preferably 20/40 to 40/20 in terms of mass ratio, and is 25 /. 35-35/25 is more preferable.

When the polyol composition of Aspect 2 is used as the polyol composition, the polyisocyanurate composition preferably contains an isocyanurate modified product of hexamethylene diisocyanate and / or a biuret modified product as the polyisocyanate compound.

(Silicone compound)
In addition to the polyol compound and the polyisocyanate compound, the outermost layer coating material contains a silicone compound different from the polyol compound. The silicone compound is a component that imparts water repellency to the coating film. Examples of the silicone compound include silicone resins, silicone oils, cured products of curable silicone resins, and reactants of reactive silicone oils. The silicone compound may be used alone or in combination of two or more. The silicone resin is a resin composed of a siloxane bond (Si—O—Si), and is a silicone having a three-dimensional structure in the molecule. Silicone oil is a silicone having a linear structure.

(Carbinol-modified silicone oil)
As the silicone compound, carbinol-modified silicone oil is preferable. The carbinol-modified silicone oil may be used alone or in combination of two or more. The carbinol-modified silicone oil is a silicone oil in which at least one carbinol group is introduced into the silicone oil. In the carbinol-modified silicone oil, the carbinol group may be introduced at the end of the molecular chain or as a side chain of the molecular chain. The carbinol-modified silicone oil preferably has a carbinol group at one end of the molecular chain or at both ends of the molecular chain.

The carbinol-modified silicone oil is preferably represented by the following general formula (1).

（式（１）中、Ｒ¹は、置換または非置換の１価の炭化水素基を示す。Ｒ²は、アルキレン基を示す。Ｒ³は、アルキレン基を示す。ｘは０〜３の整数を示す。ｙは０〜２の整数を示す。ｚは０〜６００の整数を示す。複数存在するＲ¹〜Ｒ³は、それぞれ同一でも異なっていてもよい。）

(In formula (1), R ¹ represents a substituted or unsubstituted monovalent hydrocarbon group. R ² represents an alkylene group. R ³ represents an alkylene group. X is an integer of 0 to 3. Y indicates an integer of 0 to 2. z indicates an integer of 0 to 600. A plurality of R ^{1 to} R ³ may be the same or different.)

Examples of the unsubstituted monovalent hydrocarbon group represented by R ¹ include an aliphatic hydrocarbon group and an aromatic hydrocarbon group. R ¹ existing in plural numbers may be different from each, it may all be the same.

Examples of the aliphatic hydrocarbon group include an alkyl group. The alkyl group preferably has 1 or more carbon atoms, preferably 18 or less carbon atoms, and more preferably 8 or less carbon atoms. The alkyl group may be linear, branched or cyclic. Examples of the alkyl group include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group and hexadecyl group. , Heptadecyl group, octadecyl group and other linear alkyl groups; isopropyl group, isobutyl group, sec-butyl group, tert-butyl group, isopentyl group, sec-pentyl group, neopentyl group, isooctyl group, 2-ethylhexyl group, isodecyl Branched alkyl groups such as groups; cyclic alkyl groups such as cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group and the like can be mentioned.

Examples of the aromatic hydrocarbon group include an aryl group, an alkylaryl group, and an aralkyl group. The number of carbon atoms of the aromatic hydrocarbon group is preferably 6 or more, preferably 18 or less, and more preferably 8 or less. Examples of the aryl group include a phenyl group and the like. Examples of the alkylaryl group include a tolyl group and a xsilyl group. Examples of the aralkyl group include a benzyl group, a 1-phenylethyl group, a 2-phenylethyl group, a methylbenzyl group and the like.

Examples of the substituted monovalent hydrocarbon group include those in which at least one hydrogen atom of the unsubstituted monovalent hydrocarbon group is substituted with a substituent. Examples of the substituent include halogen atoms (fluorine, chlorine, bromine, iodine, etc.). Examples of the substituted monovalent hydrocarbon group include an alkyl halide group such as a 3,3,3-trifluoropropyl group.

The R ¹ is preferably a hydrogen atom or an unsubstituted monovalent hydrocarbon group, more preferably an aliphatic hydrocarbon group having 1 to 18 carbon atoms and an aromatic hydrocarbon group having 6 to 8 carbon atoms. Yes, a hydrogen atom, a methyl group, and a phenyl group are particularly preferable.

The carbon number of the alkylene group represented by R ² or R ³ is preferably 1 or more, preferably 18 or less, and more preferably 8 or less. Examples of the alkylene group include a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, and a pentamethylene group.

The x is preferably 2 or 3. The y is preferably 2. The z is preferably 0 or more, more preferably 1 or more, still more preferably 5 or more, preferably 600 or less, more preferably 400 or less, still more preferably 250 or less.

The carbinol-modified silicone oil is more preferably represented by the following general formula (2).

（式（２）中、Ｒ⁴は、置換または非置換の１価の炭化水素基を示す。Ｒ⁵は、アルキレン基を示す。ｍは０〜２の整数を示す。ｎは０〜６００の整数を示す。複数存在するＲ⁴およびＲ⁵は、それぞれ同一でも異なっていてもよい。）

(In formula (2), R ⁴ represents a substituted or unsubstituted monovalent hydrocarbon group. R ⁵ represents an alkylene group. M represents an integer of 0 to 2. n represents 0 to 600. Indicates an integer. Multiple R ⁴ and R ⁵ may be the same or different.)

Examples of the unsubstituted monovalent hydrocarbon group represented by R ⁴ include the same groups represented by R ¹ in the general formula (1). R ⁴ there are a plurality may be different from each may all be the same. The R ⁴ is preferably a hydrogen atom or an unsubstituted monovalent hydrocarbon group, more preferably an aliphatic hydrocarbon group having 1 to 18 carbon atoms and an aromatic hydrocarbon group having 6 to 8 carbon atoms. Yes, a hydrogen atom, a methyl group, and a phenyl group are particularly preferable.

The carbon number of the alkylene group represented by R ⁵ is preferably 1 or more, preferably 18 or less, and more preferably 8 or less. Examples of the alkylene group include a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, and a pentamethylene group.

The m is preferably 2. The n is preferably 0 or more, more preferably 1 or more, further preferably 5 or more, preferably 600 or less, more preferably 400 or less, still more preferably 250 or less.

The kinematic viscosity (25 ° C.) of the carbinol-modified silicone oil is preferably 1 mm ² / s or more, more preferably 5 mm ² / s or more, still more preferably 10 mm ² / s or more, and preferably 200 mm ² / s or less. , More preferably 100 mm ² / s or less, still more preferably 50 mm ² / s or less. The kinematic viscosity of silicone oil is measured by a viscosity measuring method using a thin tube viscometer of JIS Z 8803 (2011).

The hydroxyl value of the carbinol-modified silicone oil is preferably 1 mgKOH / g or more, more preferably 5 mgKOH / g or more, further preferably 10 mgKOH / g or more, preferably 200 mgKOH / g or less, and more preferably 150 mgKOH / g or less. , More preferably 130 mgKOH / g or less.

The carbinol-modified silicone oil is available as a commercial product, for example, X-22-4039, X-22-4015, KF-6000, KF-6001, KF-6002, KF-6003, X-22-. Examples include 170BX and X-22-170DX (all manufactured by Shin-Etsu Chemical Co., Ltd.).

The content of the carbinol-modified silicone oil in the outermost layer coating material is preferably 0.01 part by mass or more, more preferably 0.05 part by mass with respect to 100 parts by mass in total of the polyol compound and the polyisocyanate compound. As mentioned above, it is more preferably 0.1 part by mass or more, preferably 20 parts by mass or less, more preferably 10 parts by mass or less, still more preferably 8 parts by mass or less. If the content is within the above range, the flight distance on a driver shot such as in rainy weather will be further improved.

(Curable silicone resin)
The outermost layer coating material may contain a curable silicone resin as a silicone compound. The curable silicone resin has an alkoxysilyl group in the molecule and is cured at room temperature by cross-linking the alkoxysilyl group in the presence of a curing catalyst described later. The silicone resin is a silicone having a three-dimensional structure in the molecule.

Examples of the curable silicone resin include a partially hydrolyzed condensate of an alkoxysilane compound represented by the general formula (3).

（式（３）中、Ｒ⁶は、水素原子、または、置換または非置換の１価の炭化水素基を示す。Ｒ⁷は、置換または非置換の１価の炭化水素基を示す。ａは、０〜３の整数を示す。複数存在するＲ⁶およびＲ⁷は、それぞれ同一でも異なっていてもよい。）

(In formula (3), R ⁶ represents a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group. R ⁷ represents a substituted or unsubstituted monovalent hydrocarbon group. A represents a substituted or unsubstituted monovalent hydrocarbon group. , 0 to 3. Multiple R ⁶ and R ⁷ may be the same or different, respectively.)

Examples of the unsubstituted monovalent hydrocarbon group represented by R ⁶ or R ⁷ include an aliphatic hydrocarbon group and an aromatic hydrocarbon group. A plurality of R ⁶ and R ⁷ may be different from each other, or all of them may be the same.

Examples of the aliphatic hydrocarbon group include an alkyl group. The alkyl group preferably has 1 or more carbon atoms, preferably 18 or less carbon atoms, and more preferably 8 or less carbon atoms. The alkyl group may be linear, branched or cyclic. Examples of the alkyl group include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group and hexadecyl group. , Heptadecyl group, octadecyl group and other linear alkyl groups; isopropyl group, isobutyl group, sec-butyl group, tert-butyl group, isopentyl group, sec-pentyl group, neopentyl group, isooctyl group, 2-ethylhexyl group, isodecyl Branched alkyl groups such as groups; cyclic alkyl groups such as cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group and the like can be mentioned.

Examples of the aromatic hydrocarbon group include an aryl group, an alkylaryl group, and an aralkyl group. The number of carbon atoms of the aromatic hydrocarbon group is preferably 6 or more, preferably 18 or less, and more preferably 8 or less. Examples of the aryl group include a phenyl group and the like. Examples of the alkylaryl group include a tolyl group and a xsilyl group. Examples of the aralkyl group include a benzyl group, a 1-phenylethyl group, a 2-phenylethyl group, a methylbenzyl group and the like.

Examples of the substituted monovalent hydrocarbon group include those in which at least one hydrogen atom of the unsubstituted monovalent hydrocarbon group is substituted with a substituent. Examples of the substituent include a halogen atom (fluorine, chlorine, bromine, iodine, etc.), a hydroxy group, a cyano group, an amino group, a carboxy group and the like. Examples of the substituted monovalent hydrocarbon group include an alkyl halide group such as a 3,3,3-trifluoropropyl group.

The R ⁶ is preferably a hydrogen atom or an unsubstituted monovalent hydrocarbon group, more preferably an aliphatic hydrocarbon group having 1 to 18 carbon atoms and an aromatic hydrocarbon group having 6 to 8 carbon atoms. Yes, a hydrogen atom, a methyl group, and a phenyl group are particularly preferable. The curable silicone resin, as R ^6, those having only methyl groups, or, preferably those having a methyl group and phenyl group.

As the R ⁷ , an unsubstituted monovalent hydrocarbon group is preferable, an aliphatic hydrocarbon group having 1 to 18 carbon atoms is more preferable, and a methyl group and an ethyl group are particularly preferable.

The a represents an integer of 0 to 3, and is preferably 1 or 2.

Examples of the alkoxysilane compound represented by the general formula (1) include methyltrimethoxysilane, methyltriethoxysilane, methyltriisopropoxysilane, methyltributoxysilane, ethyltrimethoxysilane, propyltrimethoxysilane, and dimethyl. Examples thereof include dimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, phenylmethyldimethoxysilane, tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane and tetrabutoxysilane. The alkoxysilane compound represented by the general formula (1) may be used alone or in combination of two or more.

The partially hydrolyzed condensate of the alkoxysilane compound is obtained by adding water to the alkoxysilane compound and raising the temperature with stirring in the presence of a known catalyst to cause partial hydrolysis and condensation. It is obtained by letting it.

The kinematic viscosity (25 ° C.) of the curable silicone resin is preferably 0.1 mm ² / s or more, more preferably 0.5 mm ² / s or more, still more preferably 1.0 mm ² / s or more, and 250 mm ² It is preferably less than / s, more preferably 150 mm ² / s or less, still more preferably 100 mm ² / s or less. The kinematic viscosity of the curable silicone resin is measured by a viscosity measuring method using a thin tube viscometer of JIS Z 8803 (2011).

The content of the curable silicone resin in the outermost layer coating material is preferably 20 parts by mass or less, more preferably 10 parts by mass or less, still more preferably 10 parts by mass or less, based on 100 parts by mass of the total of the polyol compound and the polyisocyanate compound. It is 5 parts by mass or less.

(Curing catalyst)
The curing catalyst is not particularly limited as long as it is a catalyst capable of curing the curable silicone resin. Examples of the curing catalyst include organic tin compounds such as dibutyltin diacetate, dibutyltin dioctylate, and dibutyltin dilaurate; and organic substances such as aluminum tris (acetylacetone), aluminum tris (acetoacetate ethyl), and aluminum diisopropoxy (acetoacetate ethyl). Aluminum compounds; organic zirconium compounds such as zirconium (acetylacetone), zirconium tris (acetylacetone), zirconium tetrakis (ethylene glycol monomethyl ether), zirconium tetrakis (ethylene glycol monoethyl ether), zirconium tetrakis (ethylene glycol monobutyl ether); titanium tetrakis (titanium tetrakis) Organic titanium compounds such as ethylene glycol monomethyl ether), titanium tetrakis (ethylene glycol monoethyl ether), and titanium tetrakis (ethylene glycol monobutyl ether); mineral acids such as hydrochloric acid, nitrate, sulfuric acid, and phosphoric acid; formic acid, acetic acid, and oxalic acid, Organic acids such as trifluoroacetic acid; inorganic bases such as ammonia, sodium hydroxide and potassium hydroxide; organic bases such as ethylenediamine and alkanolamines; amino compounds such as amino-modified silicones, aminosilanes, silazanes and amines. Of these, organotin compounds, organoaluminum compounds, organotitanium compounds, and mineral acids are preferable.

The content of the curing catalyst in the outermost layer coating material is preferably 0.1 part by mass or more, more preferably 1 part by mass or more, and further preferably 2 parts by mass with respect to 100 parts by mass of the curable silicone resin. As described above, it is preferably 50 parts by mass or less, more preferably 20 parts by mass or less, and further preferably 10 parts by mass or less.

(Reactive silicone oil)
The outermost layer coating material may contain a reactive silicone oil other than the carbinol-modified silicone as the silicone compound. The reactive silicone oil is a silicone oil in which a reactive group is introduced into a part of silicon. The reactive silicone oil preferably has a reactive group at one end of the molecular chain or at both ends. Examples of the reactive group include a hydrosilyl group (SiH), a silanol group (SiOH), and an alkoxysilyl group (SiOR (R: alkyl group)).

The reactive silicone oil is preferably represented by the general formula (4). In the reactive silicone oil, a silicon atom located at one end of a molecular chain of polysiloxane constitutes a reactive group.

（式（４）中、Ｒ⁸は、置換または非置換の１価の炭化水素基を示す。Ｒ⁹は、水素原子、ヒドロキシ基、またはアルコキシ基を示す。ｂは０〜２の整数を示す。ｃは０〜６００の整数を示す。複数存在するＲ⁸およびＲ⁹は、それぞれ同一でも異なっていてもよい。）

(In formula (4), R ⁸ represents a substituted or unsubstituted monovalent hydrocarbon group. R ⁹ represents a hydrogen atom, a hydroxy group, or an alkoxy group. B represents an integer of 0 to 2. .C represents an integer from 0 to 600. Multiple R ⁸ and R ⁹ may be the same or different.)

Examples of the unsubstituted monovalent hydrocarbon group represented by R ⁸ include an aliphatic hydrocarbon group and an aromatic hydrocarbon group. R ⁸ existing in plural, may be different from each may all be the same.

Examples of the aliphatic hydrocarbon group include an alkyl group. The alkyl group preferably has 1 or more carbon atoms, preferably 18 or less carbon atoms, and more preferably 8 or less carbon atoms. The alkyl group may be linear, branched or cyclic. Examples of the alkyl group include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group and hexadecyl group. , Heptadecyl group, octadecyl group and other linear alkyl groups; isopropyl group, isobutyl group, sec-butyl group, tert-butyl group, isopentyl group, sec-pentyl group, neopentyl group, isooctyl group, 2-ethylhexyl group, isodecyl Branched alkyl groups such as groups; cyclic alkyl groups such as cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group and the like can be mentioned.

Examples of the aromatic hydrocarbon group include an aryl group, an alkylaryl group, and an aralkyl group. The number of carbon atoms of the aromatic hydrocarbon group is preferably 6 or more, preferably 18 or less, and more preferably 8 or less. Examples of the aryl group include a phenyl group and the like. Examples of the alkylaryl group include a tolyl group and a xsilyl group. Examples of the aralkyl group include a benzyl group, a 1-phenylethyl group, a 2-phenylethyl group, a methylbenzyl group and the like.

Examples of the substituted monovalent hydrocarbon group include those in which at least one hydrogen atom of the unsubstituted monovalent hydrocarbon group is substituted with a substituent. Examples of the substituent include halogen atoms (fluorine, chlorine, bromine, iodine, etc.). Examples of the substituted monovalent hydrocarbon group include an alkyl halide group such as a 3,3,3-trifluoropropyl group.

The R ⁸ is preferably a hydrogen atom or an unsubstituted monovalent hydrocarbon group, more preferably an aliphatic hydrocarbon group having 1 to 18 carbon atoms and an aromatic hydrocarbon group having 6 to 8 carbon atoms. Yes, a hydrogen atom, a methyl group, and a phenyl group are particularly preferable.

R ⁹ represents a hydrogen atom, a hydroxy group, and an alkoxy group. The alkoxy group preferably has 1 or more carbon atoms, preferably 18 or less carbon atoms, and more preferably 8 or less carbon atoms. Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, an isobutoxy group, a sec-butoxy group and the like. Among these, as R ⁹ , an alkoxy group is preferable, and a methoxy group or an ethoxy group is more preferable.

The b is preferably 2. The c is preferably 0 or more, more preferably 1 or more, further preferably 5 or more, preferably 600 or less, more preferably 400 or less, still more preferably 250 or less.

The kinematic viscosity (25 ° C.) of the reactive silicone oil is preferably 0.65 mm ² / s or more, more preferably 2 mm ² / s or more, still more preferably 5 mm ² / s or more, and 1000 mm ² / s or less. It is preferably more preferably 500 mm ² / s or less, still more preferably 100 mm ² / s or less. The kinematic viscosity of the reactive silicone oil is measured by a viscosity measuring method using a thin tube viscometer of JIS Z 8803 (2011).

The content of the reactive silicone oil in the outermost layer coating material is preferably 10 parts by mass or less, more preferably 7 parts by mass or less, still more preferably 7 parts by mass or less, based on 100 parts by mass of the total of the polyol compound and the polyisocyanate compound. It is 5 parts by mass or less.

The content of the reactive silicone oil in the outermost layer coating material is preferably 5 parts by mass or more, more preferably 20 parts by mass or more, and further preferably 50 parts by mass with respect to 100 parts by mass of the curable silicone resin. As described above, it is preferably 200 parts by mass or less, more preferably 150 parts by mass or less, and further preferably 75 parts by mass or less.

The paint may be either a water-based paint having water as the main dispersion medium or a solvent-based paint using an organic solvent as the dispersion medium, but a solvent-based paint is preferable. In the case of solvent-based paints, preferred solvents include toluene, isopropyl alcohol, xylene, methyl ethyl ketone, methyl ethyl isobutyl ketone, ethylene glycol monomethyl ether, ethylbenzene, propylene glycol monomethyl ether, isobutyl alcohol, ethyl acetate and the like. The solvent may be blended in either the polyol composition or the polyisocyanate composition, but it is preferable to blend the solvent in each of the polyol composition and the polyisocyanate composition from the viewpoint of uniformly curing the reaction.

A known catalyst can be used for the curing reaction. Examples of the catalyst include monoamines such as triethylamine and N, N-dimethylcyclohexylamine; N, N, N', N'-tetramethylethylenediamine, N, N, N', N'', N''-. Polyamines such as pentamethyldiethylenetriamine; cyclic diamines such as 1,8-diazabicyclo [5.4.0] -7-undecene (DBU) and triethylenediamine; tin catalysts such as dibutyltin dilaurylate and dibutyltin diacetate, etc. Can be mentioned. These catalysts may be used alone or in combination of two or more. Among these, tin-based catalysts such as dibutyltin dilaurylate and dibutyltin diacetate are preferable, and dibutyltin dilaurylate is particularly preferably used.

The paint is generally contained in a golf ball paint such as an ultraviolet absorber, an antioxidant, a light stabilizer, a fluorescent whitening agent, an antiblocking agent, a leveling agent, a slip agent, and a viscosity modifier, if necessary. It may contain an additive that can be added.

When the coating film has a multi-layer structure, examples of the base resin constituting the coating film other than the outermost layer coating film include urethane resin, epoxy resin, acrylic resin, vinyl acetate resin, polyester resin, and the like. Urethane resin is preferable. The coating film other than the outer layer coating film may be formed from the same paint as the outermost layer coating film, or may be formed from other paints.

(Formation of coating film)
The coating film can be formed by applying a paint to the surface of the golf ball body. The method of applying the paint is not particularly limited, and a known method can be adopted, and examples thereof include spray coating and electrostatic coating.

In the case of spray painting using an air gun, the polyol composition and the polyisocyanate composition are supplied by their respective pumps, continuously mixed with a line mixer arranged immediately before the air gun, and the obtained mixture is sprayed. It may be painted, or the polyol composition and the polyisocyanate composition may be spray-painted separately by using an air spray system provided with a mixing ratio control mechanism. The carbinol-modified silicone oil is preferably blended in a polyol composition or a polyisocyanate composition, and more preferably blended in a polyol composition. The coating may be sprayed once or may be applied multiple times.

The paint applied to the golf ball body can form a coating film by, for example, drying at a temperature of 30 ° C. to 70 ° C. for 1 hour to 24 hours.

(Golf ball body)
The golf ball of the present invention is not particularly limited as long as it is a golf ball having a golf ball main body and at least one layer of a coating film provided on the surface of the golf ball main body. The structure of the golf ball body is not particularly limited, and may be a one-piece golf ball, a two-piece golf ball, a three-piece golf ball, a four-piece golf ball, a multi-piece golf ball equal to or higher than a five-piece golf ball, or a thread-wound golf ball. .. In any case, the present invention can be preferably applied.

(core)
The one-piece golf ball main body and the core used for the thread-wound golf ball, the two-piece golf ball, and the multi-piece golf ball will be described.

A known rubber composition (hereinafter, may be simply referred to as "rubber composition for core") can be used for the one-piece golf ball body and the core, and for example, a base rubber, a co-crosslinking agent, and a cross-linking initiator. The rubber composition containing the above can be formed by heat pressing.

As the base rubber, it is particularly preferable to use high cis polybutadiene having a cis bond advantageous for repulsion of 40% by mass or more, preferably 70% by mass or more, and more preferably 90% by mass or more. As the co-crosslinking agent, α, β-unsaturated carboxylic acid having 3 to 8 carbon atoms or a metal salt thereof is preferable, and a metal salt of acrylic acid or a metal salt of methacrylic acid is more preferable. As the metal of the metal salt, zinc, magnesium, calcium, aluminum and sodium are preferable, and zinc is more preferable. The amount of the co-crosslinking agent used is preferably 20 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the base rubber. When an α, β-unsaturated carboxylic acid having 3 to 8 carbon atoms is used as the co-crosslinking agent, it is preferable to add a metal compound (for example, magnesium oxide). Organic peroxides are preferably used as the cross-linking initiator. Specifically, dicumyl peroxide, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-di (t-butylperoxy). Examples thereof include organic peroxides such as hexane and di-t-butyl peroxide, and among these, dicumyl peroxide is preferably used. The blending amount of the cross-linking initiator is preferably 0.2 parts by mass or more, more preferably 0.3 parts by mass or more, and preferably 3 parts by mass or less, more preferably 3 parts by mass or more, based on 100 parts by mass of the base rubber. It is 2 parts by mass or less.

Further, the rubber composition for the core may further contain an organic sulfur compound. As the organic sulfur compound, diphenyl disulfides (for example, diphenyl disulfide, bis (pentabromophenyl) disulfide), thiophenols, and thionaphthols (for example, 2-thionaphthol) can be preferably used. The blending amount of the organic sulfur compound is preferably 0.1 part by mass or more, more preferably 0.3 part by mass or more, and more preferably 5.0 parts by mass or less, based on 100 parts by mass of the base rubber. It is preferably 3.0 parts by mass or less. The rubber composition for a core may further contain a carboxylic acid and / or a salt thereof. As the carboxylic acid and / or a salt thereof, a carboxylic acid having 1 to 30 carbon atoms and / or a salt thereof is preferable. As the carboxylic acid, either an aliphatic carboxylic acid or an aromatic carboxylic acid (benzoic acid or the like) can be used. The blending amount of the carboxylic acid and / or its salt is 1 part by mass or more and 40 parts by mass or less with respect to 100 parts by mass of the base rubber.

In the core rubber composition, in addition to the base rubber, the co-crosslinking agent, the cross-linking initiator, and the organic sulfur compound, a weight adjusting agent such as zinc oxide and barium sulfate, an antiaging agent, and a colored powder are appropriately added. Can be blended. The heating press molding conditions of the rubber composition for the core may be appropriately set according to the rubber composition, but are usually heated at 130 ° C. to 200 ° C. for 10 minutes to 60 minutes, or 20 at 130 ° C. to 150 ° C. After heating for 1 to 40 minutes, it is preferable to heat at 160 ° C. to 180 ° C. for 5 to 15 minutes in two steps.

(cover)
The golf ball body preferably has a core and a cover that covers the core. In this case, the slab hardness of the cover composition is preferably set appropriately according to the desired performance of the golf ball. For example, in the case of a distance-type golf ball that emphasizes flight distance, the slab hardness of the cover composition is preferably 50 or more, more preferably 55 or more, further preferably 60 or more, and preferably 80 or less in terms of shore D hardness. 70 or less is more preferable, and 68 or less is further preferable. By setting the slab hardness of the cover composition to 50 or more, a golf ball having a high launch angle and low spin can be obtained in a driver shot and a long iron shot, and the flight distance is improved. Further, by setting the slab hardness of the cover composition to 80 or less, a golf ball having excellent durability can be obtained. Further, in the case of a spin-type golf ball in which controllability is important, the slab hardness of the cover composition is the shore D hardness, preferably less than 50, preferably 20 or more, more preferably 23 or more, still more preferably 25 or more. .. When the slab hardness of the cover composition is less than 50 in the shore D hardness, the spin amount of the approach shot becomes high, and a golf ball that easily stops on the green can be obtained. Further, by setting the slab hardness to 20 or more, the scratch resistance is improved. In the case of a plurality of cover layers, the slab hardness of the cover composition constituting each layer may be the same or different as long as it is within the above range.

In the case of a distance-type golf ball that emphasizes flight distance, the thickness of the cover is preferably 0.3 mm or more, more preferably 0.5 mm or more, still more preferably 0.7 mm or more, and 2.5 mm or less. It is preferable, more preferably 2.2 mm or less, still more preferably 2.0 mm or less. When the thickness of the cover is 0.3 mm or more, the resilience of the golf ball can be maintained, and when the thickness is 2.5 mm or less, the shot feeling of the golf ball becomes better.

In the case of a spin-type golf ball that emphasizes controllability, the thickness of the cover is preferably 0.1 mm or more, more preferably 0.2 mm or more, still more preferably 0.3 mm or more, and 2.0 mm or less. It is preferably 1.5 mm or less, still more preferably 1.0 mm or less. When the thickness of the cover is 0.1 mm or more, the shot feeling of the golf ball becomes better, and when the thickness is 2.0 mm or less, the resilience of the golf ball can be maintained.

The resin component constituting the cover is not particularly limited, and for example, various resins such as ionomer resin, polyester resin, urethane resin, and polyamide resin, and the trade name "Pevax (registered trademark)" from Alchema Co., Ltd. For example, a thermoplastic polyamide elastomer marketed under "Pevax 2533") ", marketed under the trade name" Hytrel (registered trademark) "(for example," Hytrel 3548 "," Hytrel 4047 ")" from Toray DuPont Co., Ltd. Thermoplastic Polyamide Elastomer, a thermoplastic polyurethane elastomer marketed under the trade name "Elastran (registered trademark)" (for example, "Elastran XNY97A") from BASF Japan Co., Ltd., a trade name from Mitsubishi Chemical Co., Ltd. Examples thereof include thermoplastic styrene elastomers commercially available under "Labalon (registered trademark)" and thermoplastic polyester-based elastomers commercially available under the trade name "Primaloy". The cover material may be used alone or in combination of two or more.

Among these, as the resin component constituting the cover, a polyurethane resin is preferable in the case of a spin-type golf ball that emphasizes controllability, and an ionomer resin is preferable in the case of a distance-type golf ball that emphasizes flight distance. When a polyurethane resin is used as the resin component constituting the cover, the content of the polyurethane resin in the resin component is preferably 50% by mass or more, more preferably 70% by mass or more, and further preferably 90% by mass or more. .. When an ionomer resin is used as the resin component constituting the cover, the content of the ionomer resin in the resin component is preferably 50% by mass or more, more preferably 70% by mass or more, and further preferably 90% by mass or more. ..

The polyurethane may be in any form of so-called thermoplastic polyurethane or thermosetting polyurethane. The thermoplastic polyurethane is a polyurethane that exhibits plasticity by heating, and generally means a polyurethane having a linear structure having a high molecular weight to some extent. On the other hand, thermosetting polyurethane (two-component curable polyurethane) is obtained by reacting a low molecular weight urethane prepolymer with a curing agent (chain length extender) to increase the molecular weight when molding the cover. It is polyurethane. The thermosetting polyurethane includes a polyurethane having a linear structure and a polyurethane having a three-dimensional crosslinked structure by controlling the number of functional groups of the prepolymer and the curing agent (chain length extender) used. As the polyurethane, a thermoplastic elastomer is preferable.

In addition to the above-mentioned resin components, the cover includes pigment components such as white pigments (for example, titanium oxide), blue pigments, and red pigments, specific gravity adjusting agents such as calcium carbonate and barium sulfate, dispersants, antiaging agents, and ultraviolet absorption. An agent, a light stabilizer, a fluorescent material, a fluorescent whitening agent, or the like may be contained within a range that does not impair the performance of the cover.

The mode in which the cover is molded using the cover composition is not particularly limited, but the mode is that the cover composition is injection-molded directly onto the core, or a hollow shell-shaped shell is molded from the cover composition and the core is formed. Is covered with a plurality of shells and compression-molded (preferably, a hollow shell-shaped half-shell is formed from a cover composition, and the core is coated with two half-shells and compression-molded). Can be done. It is preferable that the golf ball body having the cover formed is taken out from the mold and, if necessary, surface-treated such as deburring, cleaning, and sandblasting. Also, if desired, a mark can be formed.

The total number of dimples formed on the cover is preferably 200 or more and 500 or less. If the total number of dimples is less than 200, it is difficult to obtain the effect of dimples. Further, when the total number of dimples exceeds 500, the size of each dimple becomes small, and it is difficult to obtain the effect of dimples. The shape of the dimples to be formed (planar shape) is not particularly limited, and a circle; a polygon such as a substantially triangle, a substantially quadrangle, a substantially pentagon, and a substantially hexagon; and other indefinite shapes; are used alone. Alternatively, two or more kinds may be used in combination.

When the golf ball is a multi-piece golf ball of three-piece, four-piece golf ball, five-piece golf ball or higher, the intermediate layer provided between the core and the outermost layer cover is, for example, a polyurethane resin or an ionomer resin. , Polypolymer resin, thermoplastic resin such as polyethylene; thermoplastic elastomer such as styrene elastomer, polyolefin elastomer, polyurethane elastomer, polyester elastomer; cured product of rubber composition and the like. Here, as the ionomer resin, for example, at least a part of the carboxyl group in the copolymer of ethylene and α, β-unsaturated carboxylic acid is neutralized with a metal ion, or ethylene and α, β-unmodified. Examples thereof include those in which at least a part of the carboxyl groups in the ternary copolymer of saturated carboxylic acid and α, β-unsaturated carboxylic acid ester is neutralized with metal ions. The intermediate layer may further contain a specific gravity adjusting agent such as barium sulfate or tungsten, an antiaging agent, a pigment or the like. The intermediate layer may be referred to as an inner cover layer or an outer layer core depending on the configuration of the golf ball.

The diameter of the golf ball is preferably 40 mm to 45 mm. From the viewpoint of satisfying the R & A (Royal and Ancient Golf Club of St Andrews) standard, the diameter is preferably 42.67 mm or more. From the viewpoint of air resistance, the diameter is preferably 44 mm or less, more preferably 42.80 mm or less. The mass of the golf ball is preferably 40 g or more and 50 g or less. From the viewpoint that a large inertia can be obtained, the mass is preferably 44 g or more, more preferably 45.00 g or more. From the viewpoint that the R & A standard is satisfied, the mass is preferably 45.93 g or less.

When the golf ball has a diameter of 40 mm to 45 mm, the amount of compression deformation (amount of shrinkage in the compression direction) when the final load of 1275 N is applied from the state where the initial load of 98 N is applied is preferably 2.0 mm or more. It is more preferably 2.2 mm or more, preferably 5.0 mm or less, and more preferably 4.5 mm or less. A golf ball having a compression deformation amount of 2.0 mm or more does not become too hard and has a good shot feeling. On the other hand, when the amount of compression deformation is 5.0 mm or less, the resilience is increased.

FIG. 1 is a partially cutaway sectional view showing a golf ball 1 according to an embodiment of the present invention. The golf ball 1 has a spherical core 2, an intermediate layer 3 that covers the spherical core 2, a cover 4 that covers the intermediate layer 3, and a coating film 5 provided on the surface of the cover 4. A large number of dimples 41 are formed on the surface of the cover 4. The portion of the surface of the cover 4 other than the dimples 41 is the land 42. The coating film 5 is formed of a polyisocyanate composition, a polyol composition, and a coating material containing a silicone compound.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited to the following Examples, and modifications and embodiments within the scope of the present invention are all described in the present invention. Included in the range.

[Evaluation methods]
(1) Core hardness (shore C hardness)
The hardness measured on the surface of the core was defined as the core surface hardness. Further, the core was cut into a hemisphere, and the hardness measured at the center of the cut surface was defined as the core center hardness. The hardness was measured using an automatic hardness tester (Digitest II, manufactured by H. Burleys). As the detector, "Shore C" was used.

(2) Slab hardness (Shore D hardness)
A sheet having a thickness of about 2 mm was prepared by injection molding using the composition for the intermediate layer and the composition for the cover, and stored at 23 ° C. for 2 weeks. The hardness was measured using an automatic hardness tester (Digitest II, manufactured by H. Burleys) with three or more of these sheets stacked so as not to be affected by the measuring substrate or the like. As the detector, "Shore D" was used.

(3) Compressive deformation amount (mm)
The amount of deformation in the compression direction (the amount of core contraction in the compression direction) from the state in which the initial load of 98N was applied to the core to the time when the final load of 1275N was applied was measured.

(4) Baking coating plate The material of the test piece forming the coating film was the steel plate SPCC specified in JIS G 4314, and the shape was 0.8 mm in thickness, 70 mm in width, and 150 mm in length. Primer surfacers were spray-coated on both sides of the test piece and dried. Subsequently, the surface was polished with water-resistant abrasive paper (P400) until the surface became smooth, washed with detergent and water, and dried. Next, acrylic melamine-based resin enamel was spray-coated, left at room temperature for 20 minutes, and then forcibly dried at 160 ° C. for 20 minutes to prepare a baking finish.
A coating film was formed on the obtained baking sheet under the same conditions as when the golf ball was manufactured, and the water sliding angle on the surface of the coating film was measured.

(5) Film thickness of coating film The surface of the golf ball was cut with a slicer and measured with a microscope.

(6) Water sliding angle The water sliding angle was measured using a sliding contact angle meter (DMo-501SA, manufactured by Kyowa Interface Science Co., Ltd.). The measurement conditions were as follows. In the measurement of golf balls, water was dropped into the center of the dimple with the largest diameter.
Measurement method: Sliding method Analysis method: Perfect circle fitting method (section 60 dots)
Field of view: WIDE1
Water volume: 19 ± 1 μL (needle used: stainless steel needle 15G)
Sliding conditions: 0 to 90 ° (2.0 ° continuous inclination per second)
Sliding down, movement judgment distance: Tilt angle when moving 3 dots or more

(7) Water contact angle The water contact angle was measured using a contact angle meter (DropMaster DM501 manufactured by Kyowa Interface Science Co., Ltd., analysis software (FAMAS)). An injection tube set 22G manufactured by Kyowa Interface Science Co., Ltd. was used as a glass injection tube for droplets.
In the measurement, the software was first started and the injection tube was set in the contact angle meter. Subsequently, the measurement sample was set on the sample table so that the portion where water was dropped on the monitor was horizontal. Then, 2 μL of water was dropped from the injection tube, and the contact angle was measured 30 seconds after the drop. The contact angle was measured using the θ / 2 method. In the measurement of golf balls, water was dropped into the center of the dimple with the largest diameter.

(8) Dynamic friction coefficient The dynamic friction coefficient of a golf ball was measured under the following conditions. Under the following conditions, the load is small and the moving speed is slow, so that the coefficient of dynamic friction of the outermost coating film can be measured.
・ Testing machine: Tribomaster TL201TS (manufactured by Tribology)
-Measurement sample; Golf ball-Face plate; Stainless steel (manufactured by Nisshin Steel Co., Ltd., HT1770 (dimensions: 50 mm x 150 mm x thickness 2 mm)) with arithmetic mean roughness Ra of the face surface: 2.9 μm, maximum height An average value Ry: 21.7 μm was used.
-Method for producing face plate: The stainless steel was obtained by air blasting. As the abrasive, a mixture of alumina powder (# 60) and STEEL BALL (manufactured by Ervin industries, ES300) at a ratio of 1: 1 is used, and the blasting conditions are the distance between the face plate and the nozzle of 10 cm and immediately before the nozzle. The pressure was 4 to 6 kg / cm ² .
-Measuring method of Ra and Ry: A surface roughness measuring machine (manufactured by Mitutoyo Co., Ltd., SJ-301) was used, and the measurement was performed by a method conforming to JIS B 0601-1994. Ra and Ry are average values of 6 measurement points, respectively. The cutoff value λc was 2.5 mm.
・ Temperature: 23 ℃
・ Ball movement speed: 2 mm / s
-Load; 1.96N (200gf)
-Measurement method: The ball was fixed with a chuck and moved on a flat plate at a constant speed with a load of 200 gf applied to measure the dynamic friction force.
・ Measurement item: Dynamic friction (average value in 2-10 mm section)

(9) Driver Shot A driver (Sumitomo Rubber Industries, Ltd. brand name "SRIXON Z765", shaft hardness: X, loft angle: 8.5 °) was attached to the swing machine of Golf Laboratory. A golf ball was hit under the condition that the head speed was 50 m / sec, and the spin rate and carry were measured. Carry is the distance from the launch point to the drop point, and the spin speed (rpm) was measured by taking continuous photographs of the hit golf ball. An average value was obtained by measuring 10 times. The club face and ball were wet and measurements were taken in the rain.

(10) Long Iron Shot A No. 5 iron (trade name "SRIXON Z765" of Sumitomo Rubber Industries, Ltd., shaft hardness: S, loft angle: 25 °) was attached to the swing machine of Golf Laboratory. A golf ball was hit under the condition that the head speed was 41 m / sec, and the spin rate and carry were measured. Carry is the distance from the launch point to the drop point, and the spin speed (rpm) was measured by taking continuous photographs of the hit golf ball. An average value was obtained by measuring 10 times. The club face and ball were wet and measurements were taken in the rain.

(11) Approach Shot A sand wedge (manufactured by Cleveland Golf, RTX-3 BLD, loft angle 58 °) was attached to a swing robot of Golf Laboratory, and a golf ball was hit at a head speed of 16 m / s. The spin speed (rpm) was measured by taking continuous photographs of the golf ball. The measurement was performed 10 times for each golf ball, and the average value was taken as the spin speed. The club face and ball were wet and measurements were taken in the rain.

[Manufacturing of golf ball body]
1. 1. Preparation of Spherical Core A spherical core having a diameter of 39.7 mm was obtained by kneading the rubber compositions having the formulations shown in Table 1 and heating and pressing them at 150 ° C. for 19 minutes in an upper and lower mold having a hemispherical cavity. The amount of barium sulfate was adjusted so that the ball mass was 45.6 g.

Polybutadiene rubber: JSR Corporation, "BR730 (Hysis polybutadiene)"
Zinc acrylate: "ZN-DA90S" manufactured by Nippon Distillery Co., Ltd.
Zinc oxide: "Ginmine R" manufactured by Toho Zinc Co., Ltd.
Barium Sulfate: "Barium Sulfate BD" manufactured by Sakai Chemical Industry Co., Ltd.
Bis (pentabromophenyl) disulfide: Kawaguchi Chemical Industry Co., Ltd. Dicumyl peroxide: NOF Corporation, "Park Mill (registered trademark) D"
Benzoic acid: manufactured by Emerald Kalama Chemical

2. Preparation of Intermediate Layer Composition and Cover Composition The materials of the formulations shown in Tables 2 and 3 are mixed by a twin-screw kneading extruder to obtain a pelletized intermediate layer composition and cover composition. Prepared. The extrusion conditions were a screw diameter of 45 mm, a screw rotation speed of 200 rpm, and a screw L / D = 35, and the compound was heated to 160 to 230 ° C. at the position of the die of the extruder.

ハイミラン（登録商標）ＡＭ７３２９：三井・デュポン・ポリケミカル社製、亜鉛イオン中和エチレン−メタクリル酸共重合体アイオノマー樹脂
ハイミラン１５５５：三井・デュポン・ポリケミカル社製、ナトリウムイオン中和エチレン−メタクリル酸共重合体アイオノマー樹脂

Hymilan (registered trademark) AM7329: Mitsui-Dupont Polychemical, zinc ion-neutralized ethylene-methacrylic acid copolymer ionomer resin Hymilan 1555: Mitsui-Dupont Polychemical, sodium ion-neutralized ethylene-methacrylic acid Polymer ionomer resin

エラストラン（登録商標）ＮＹ８０Ａ：ＢＡＳＦジャパン社製、熱可塑性ポリウレタンエラストマー

Elastran (registered trademark) NY80A: Thermoplastic polyurethane elastomer manufactured by BASF Japan Ltd.

3. 3. Molding of Intermediate Layer By injection molding the composition for intermediate layer obtained above directly onto the spherical core obtained as described above, an intermediate layer (thickness: 1.0 mm) covering the spherical core can be obtained. Formed.

4. Preparation of Reinforcing Layer A composition for a reinforcing layer (manufactured by Shinto Paint Co., Ltd., trade name "Porin (registered trademark) 750LE") using a two-component curable epoxy resin as a base resin was prepared. The main agent contains 30 parts by mass of a bisphenol A type solid epoxy resin and 70 parts by mass of a solvent. The curing agent contains 40 parts by mass of the modified polyamide amine, 5 parts by mass of titanium dioxide, and 55 parts by mass of the solvent. The mass ratio of the main agent and the curing agent was 1/1. This composition for a reinforcing layer was applied to the surface of the intermediate layer with an air gun and held in an atmosphere of 23 ° C. for 12 hours to form a reinforcing layer. The thickness of the reinforcing layer was 7 μm.

5. Cover molding One pellet-shaped cover composition was added to each recess in the lower mold of the half-shell molding die, and pressure was applied to mold the half-shell. The sphere on which the reinforcing layer was formed was concentrically covered with two half shells. The sphere and half shell were placed in a final mold with a large number of pimples on the cavity surface. A cover (thickness: 0.5 mm) was molded by compression molding to obtain a golf ball body. A large number of dimples having an inverted shape of the pimples were formed on the cover.

6. Preparation of coating film (1) Preparation of polyol composition Polytetramethylene ether glycol (PTMG, number average molecular weight: 650) and trimethylolpropane (TMP) were dissolved in a solvent (toluene, methyl ethyl ketone) as the first polyol component. The molar ratio of PTMG to TMP (TMP: PTMG) was 1.87: 1. To this, dibutyltin laurate was added as a catalyst so as to be 0.1% by mass with respect to the whole main agent. Isophorone diisocyanate (IPDI) as a first polyisocyanate component was added dropwise and mixed while maintaining this polyol solution at 80 ° C. The molar ratio (NCO / OH) of the OH group of the first polyol component and the NCO group of the first polyisocyanate component was set to 0.6. After the dropping, stirring was continued until the isocyanate was exhausted, and then the mixture was cooled at room temperature to prepare a polyol composition containing a urethane polyol (urethane polyol content: 30% by mass). The obtained urethane polyol had a PTMG content of 46.2% by mass, a hydroxyl value of 128.0 mgKOH / g, and a weight average molecular weight of 7200.

(2) Preparation of Polyisocyanate Composition 30 parts by mass of a bullet-modified hexamethylene diisocyanate (Duranate (registered trademark) 21S-75E (NCO content: 15.5%) manufactured by Asahi Kasei Chemicals Co., Ltd.), isocyanate of hexamethylene diisocyanate Nurate modified product (Asahi Kasei Chemicals Co., Ltd., Duranate TKA-100 (NCO content: 21.7%)) 30 parts by mass, isocyanurate modified product of isophorone diisocyanate (Degusa Co., Ltd., VESTANAT® T1890 (NCO content rate) 12.0%)) 40 parts by mass were mixed to prepare a polyisocyanate composition.

(3) Preparation of paint The materials shown in Table 4 were blended to obtain a paint composition No. 1-No. 6 was prepared. As for the compounding ratio of the polyol composition and the polyisocyanate composition, the molar ratio (NCO / OH) of the OH group in the polyol composition and the NCO group in the polyisocyanate composition is 1.2 / 1.0. Adjusted to be.

カルビノール変性シリコーンオイルＮｏ．１：信越化学社製、Ｘ−２２−４０３９（動粘度（２５℃）：９０ｍｍ²／ｓ、水酸基価：５８ｍｇＫＯＨ／ｇ、ポリシロキサン分子鎖の末端ではないケイ素原子にカルビノール基が導入されたシリコーンオイル）
カルビノール変性シリコーンオイルＮｏ．２：信越化学社製、ＫＦ−６０００（動粘度（２５℃）：３５ｍｍ²／ｓ、水酸基価：１２０ｍｇＫＯＨ／ｇ、式（１）で表されるカルビノール変性シリコーンオイル（Ｒ¹：置換または非置換の１価の炭化水素基、Ｒ²：アルキレン基、Ｒ³：アルキレン基、ｘ：２の整数、ｙ：２の整数、ｚ：０〜６００））
カルビノール変性シリコーンオイルＮｏ．３：信越化学社製、Ｘ−２２−１７０ＢＸ（動粘度（２５℃）：４０ｍｍ²／ｓ、水酸基価：２０ｍｇＫＯＨ／ｇ、式（２）で表されるカルビノール変性シリコーンオイル（Ｒ⁴：置換または非置換の１価の炭化水素基、Ｒ⁵：アルキレン基、ｍ：２の整数、ｚ：０〜６００））
カルボキシ変性シリコーンオイル：信越化学社製、Ｘ−２２−１６２Ｃ（動粘度（２５℃）：２２０ｍｍ²／ｓ、官能基当量：２３００ｇ／ｍｏｌ、ポリシロキサン分子鎖の両末端に位置するケイ素原子にカルボキシ基が導入されたシリコーンオイル）

Carbinol-modified silicone oil No. 1: Shin-Etsu Chemical Co., Ltd., X-22-4039 (kinematic viscosity (25 ° C.): 90 mm ² / s, hydroxyl value: 58 mgKOH / g, carbinol group introduced into silicon atom not at the end of polysiloxane molecular chain Silicone oil)
Carbinol-modified silicone oil No. 2: KF-6000 manufactured by Shin-Etsu Chemical Co., Ltd. (kinematic viscosity (25 ° C.): 35 mm ² / s, hydroxyl value: 120 mgKOH / g, hydrocarbon-modified silicone oil represented by the formula (1) (R ¹ : substituted or non-substituted) Substitution monovalent hydrocarbon group, R ² : alkylene group, R ³ : alkylene group, x: 2 integer, y: 2 integer, z: 0-600))
Carbinol-modified silicone oil No. 3: X-22-170BX manufactured by Shin-Etsu Chemical Co., Ltd. (kinematic viscosity (25 ° C.): 40 mm ² / s, hydroxyl value: 20 mgKOH / g, hydrocarbon-modified silicone oil represented by the formula (2) (R ⁴ : substitution) Or an unsubstituted monovalent hydrocarbon group, R ⁵ : alkylene group, m: 2 integer, z: 0 to 600))
Carboxylic acid-modified silicone oil: manufactured by Shin-Etsu Chemical Co., Ltd., X-22-162C (kinematic viscosity (25 ° C.): 220 mm ² / s, functional group equivalent: 2300 g / mol, carboxy to silicon atoms located at both ends of the polysiloxane molecular chain Silicone oil with introduced group)

7. Formation of coating film The surface of the golf ball body obtained above is sandblasted and marked, then the paint is applied with a spray gun, and the paint is dried in an oven at 40 ° C. for 24 hours to have a diameter of 42.7 mm. , A golf ball having a mass of 45.6 g was obtained. The painting was carried out by placing the golf ball body on a rotating body provided with a prong, rotating the rotating body at 300 rpm, blowing an air gun from the golf ball body by a distance (7 cm), and moving the golf ball in the vertical direction. The interval of each recoating was 1.0 second. The spraying conditions of the air gun are: recoating; 2 times, spraying air pressure; 0.15 MPa, pumping tank air pressure; 0.10 MPa, 1 time coating time; 1 second, atmospheric temperature; 20 ° C to 27 ° C, atmospheric humidity; It was painted under the condition of 65% or less. The evaluation results of the obtained golf balls are shown in Table 5.

Golf ball No. In Nos. 1 to 4, the outermost layer coating film is formed of a coating film containing a polyol compound, a polyisocyanate compound, and a silicone compound, and the water sliding angle of the surface of the outermost layer coating film is less than 50 °. The dynamic friction coefficient of the surface of the outermost layer coating film is 0.3 to 0.9. All of these golf balls have a long flight distance for driver shots in rainy weather and a large amount of spin for approach shots in rainy weather.

Golf ball No. In No. 5, the outermost layer coating film is formed of a coating material containing a polyol compound, a polyisocyanate compound, and a carboxy-modified silicone oil, and the water sliding angle of the surface of the outermost layer coating film is more than 50 °. Golf ball No. In No. 6, the outermost coating film is formed of a paint that does not contain silicone oil. All of these golf balls have a short flight distance for driver shots in rainy weather, and have a small amount of spin for approach shots in rainy weather.

1: Golf ball 2: Spherical core 3: Intermediate layer 4: Cover, 41: Dimple, 42: Land, 5: Coating film

Claims (9)

It has a golf ball body and at least one layer of a coating film that covers the golf ball body.
The outermost coating film is formed of a coating material containing a polyol compound, a polyisocyanate compound, and a silicone compound.
The water sliding angle on the surface of the outermost coating film is less than 50 °.
A golf ball having a coefficient of dynamic friction on the surface of the outermost coating film of 0.3 to 0.9. The golf ball according to claim 1, wherein the water contact angle on the surface of the outermost layer coating film is 75 ° or more. The golf ball according to claim 1 or 2, wherein the silicone compound is a carbinol-modified silicone oil. The golf ball according to claim 3, wherein the carbinol-modified silicone oil has a carbinol group at one end of the molecular chain or at both ends of the molecular chain. The golf ball according to claim 3 or 4, wherein the carbinol-modified silicone oil is represented by the following general formula (1).

(In formula (1), R ¹ represents a substituted or unsubstituted monovalent hydrocarbon group. R ² represents an alkylene group. R ³ represents an alkylene group. X is an integer of 0 to 3. Y indicates an integer of 0 to 2. z indicates an integer of 0 to 600. A plurality of R ^{1 to} R ³ may be the same or different.) The golf ball according to any one of claims 3 to 5, wherein the carbinol-modified silicone oil is represented by the following general formula (2).

(In formula (2), R ⁴ represents a substituted or unsubstituted monovalent hydrocarbon group. R ⁵ represents an alkylene group. M represents an integer of 0 to 2. n represents 0 to 600. Indicates an integer. Multiple R ⁴ and R ⁵ may be the same or different.) The item according to any one of claims 3 to 6, wherein the content of the carbinol-modified silicone oil is 0.1 part by mass to 20 parts by mass with respect to 100 parts by mass in total of the polyol compound and the polyisocyanate compound. Golf ball. The golf ball according to any one of claims 1 to 7, wherein the polyol compound contains a urethane polyol. The polyol compound contains a polyrotaxane having a cyclic molecule having at least one hydroxy group and a linear molecule that fits inside the ring of the cyclic molecule and holds the cyclic molecule slidably and rotatably. The golf ball according to any one of claims 1 to 7.

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