JP2017108846A - Resin composition for golf ball and golf ball - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide material for golf ball that imparts excellent striking feeling and resilience to a golf ball.SOLUTION: A resin composition for golf ball has (A) olefinic ionomer resin and (B) modified nano cellulose. The (B) modified nano cellulose is characterized in that hydrogen atoms of hydroxy groups included in cellulose constituting nano cellulose are at least partially substituted with substituents including at least one hydrophobic group selected from alkyl groups, alkenyl groups, alkylene groups, alkenylene groups and arylene groups.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a golf ball resin composition and a golf ball using the golf ball resin composition.

  Golf balls are generally required to have durability, good shot feel (flexibility), and flight distance (rebound). In recent years, it has been proposed to improve the performance of golf balls by incorporating fillers such as organic short fibers, metals and clay minerals in addition to the resin component into the components of the golf balls.

  For example, Patent Document 1 describes a golf ball having a core and an outer layer portion surrounding the core, and the outer layer portion is made of a resin composition containing a layered silicate that is cation-treated in a resin matrix. (See Patent Document 1 (Claim 1)). Patent Document 2 includes a core, an intermediate layer that covers the core, and a cover layer that covers the intermediate layer, and the intermediate layer includes a cation-treated layered silicate. A golf ball is described (see Patent Document 2 (Claim 1)).

  Patent Document 3 discloses a polymer having a structure in which particles of an inorganic material react and are substantially uniformly dispersed, and each of the particles has a maximum particle size of about 1 μm or less. A golf ball containing a nanocomposite material having a maximum particle size that is at least an order of magnitude larger than the diameter is described (see Patent Document 3 (Claim 1)). Patent Document 4 includes (a) at least one polymer selected from the group consisting of thermoplastic elastomers, carboxylic acid-based thermoplastic ionomers, polyurethane-ureas, thermoplastic polyurethanes and thermosetting polyurethanes; and (b) organic A golf ball having a component including a composition including a micropulp manufactured from fiber is described (see Patent Document 4 (Claim 1)).

JP 2006-043447 A JP 2006-095286 A JP-T-2004-504900 JP 2006-528539 A

  Like the golf balls described in Patent Documents 1 to 3, a golf ball including a constituent member in which an inorganic filler is blended has a high resilience, but has a problem that a shot feeling is lowered. That is, when the resilience is increased by increasing the rigidity of the components of the golf ball, the feel at impact is reduced. For this reason, it has been difficult for conventional golf ball resin compositions to achieve both shot feel and resilience. Further, in the golf ball described in Patent Document 4, the durability is improved by the organic fiber, but this also does not achieve both the feel at impact and the resilience.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a golf ball material that imparts excellent feel at impact and resilience to a golf ball, and a golf ball using the same. .

  The resin composition for a golf ball of the present invention that has solved the above-mentioned problems contains (A) an olefinic ionomer resin and (B) a modified nanocellulose. At least a part of the hydrogen of the hydroxyl group of the cellulose constituting the cellulose is substituted with a substituent containing at least one hydrophobic group selected from the group consisting of an alkyl group, an alkenyl group, an alkylene group, an alkenylene group and an arylene group It is characterized by being made.

  According to the present invention, a golf ball having excellent feel at impact and resilience can be obtained.

1 is a partially cutaway sectional view showing a golf ball according to an embodiment of the present invention. Golf ball no. 2 is a drawing-substituting photograph showing the crystalline state around the modified nanocellulose of one intermediate layer. Golf ball no. 10 is a drawing-substituting photograph showing a crystalline state around carbon powder of 10 intermediate layers.

  The resin composition for a golf ball of the present invention contains (A) an olefin ionomer resin and (B) a modified nanocellulose, and the (B) modified nanocellulose has a hydroxyl group contained in the cellulose constituting the nanocellulose. It is characterized in that at least a part of hydrogen is substituted with a substituent containing at least one hydrophobic group selected from the group consisting of an alkyl group, an alkenyl group, an alkylene group, an alkenylene group and an arylene group. To do.

  When the golf ball resin composition is formed into a component, (A) the olefinic ionomer resin polyethylene chain lamellar crystals are easily formed on the outer periphery of the (B) modified nanocellulose, and the lamellar crystals are large. Easy to grow. Since the crystalline component of polyethylene is less likely to be deformed than the non-crystalline component, increasing the crystalline component can increase the rebound of the component. In addition, (A) the olefinic ionomer resin contains a mixture of crystalline and amorphous components of polyethylene. Here, hardness is a local mechanical property. Therefore, the softness of the amorphous component is largely reflected in the material hardness, and the hardness of the component formed from the golf ball resin composition is lowered. Therefore, by using the golf ball resin composition, it is possible to form a constituent member having low hardness and high resilience. A golf ball having such a constituent member has a good shot feeling and high resilience.

[(A) Olefin ionomer resin]
The (A) olefin-based ionomer resin is an ionomer resin in which a copolymer of an olefin and an unsaturated carboxylic acid is used as a base polymer, and a carboxy group of the copolymer is neutralized with a metal ion. The copolymer may contain other monomer components other than olefin and unsaturated carboxylic acid.

  Examples of the (A) olefin ionomer resin include (a1) a metal ion neutralized product of a binary copolymer of an olefin and an α, β-unsaturated carboxylic acid having 3 to 8 carbon atoms (hereinafter referred to as “(a1 ) And / or (a2) an olefin, an α, β-unsaturated carboxylic acid having 3 to 8 carbon atoms and an α, β-unsaturated carboxylic acid ester. And a metal ion neutralized product of the ternary copolymer (hereinafter sometimes referred to as “(a2) ternary ionomer resin”).

  Examples of the olefin include ethylene and propylene, and ethylene is particularly preferable. Examples of the α, β-unsaturated carboxylic acid having 3 to 8 carbon atoms include acrylic acid, methacrylic acid, fumaric acid, maleic acid, and crotonic acid, and acrylic acid or methacrylic acid is preferable.

  The α, β-unsaturated carboxylic acid ester is preferably an alkyl ester of 3 to 8 carbon atoms, α, β-unsaturated carboxylic acid, more preferably an alkyl ester of acrylic acid, methacrylic acid, fumaric acid or maleic acid. In particular, acrylic acid alkyl esters or methacrylic acid alkyl esters are preferred. Examples of the alkyl group constituting the ester include methyl, ethyl, propyl, n-butyl, and isobutyl ester.

  The (a1) binary ionomer resin is preferably a metal ion neutralized product of an ethylene- (meth) acrylic acid binary copolymer. The (a2) ternary ionomer resin is preferably a metal ion neutralized product of a terpolymer of ethylene, (meth) acrylic acid and (meth) acrylic ester. Here, (meth) acrylic acid means acrylic acid and / or methacrylic acid.

  The (a1) binary copolymer constituting the binary ionomer resin and (a2) the ternary copolymer constituting the ternary ionomer resin have a content of the olefin component in the copolymer, 50 mass% or more is preferable, More preferably, it is 70 mass% or more, More preferably, it is 75 mass% or more, 95 mass% or less is preferable, More preferably, it is 92 mass% or less, More preferably, it is 87 mass% or less. If the content of the olefin component is 50% by mass or more, lamellar crystals are more easily generated around the modified nanocellulose, and the member formed from the golf ball resin composition is more repulsive, and is 95% by mass or less. Then, the member formed from the resin composition for golf balls does not become too hard, and the feel at impact of the resulting golf ball is improved.

  The (a1) binary copolymer constituting the binary ionomer resin, and (a2) the ternary copolymer constituting the ternary ionomer resin have 3 to 8 carbon atoms in the copolymer. The content of the α, β-unsaturated carboxylic acid component is preferably 4% by mass or more, more preferably 6% by mass or more, still more preferably 8% by mass or more, and preferably 50% by mass or less, more preferably 20%. It is at most 15% by mass, more preferably at most 15% by mass. When the content of the α, β-unsaturated carboxylic acid component having 3 to 8 carbon atoms is 4% by mass or more, the resilience of the golf ball resin composition is further improved, and when the content is 50% by mass or less, golf is performed. The member formed from the resin composition for balls does not become too hard, and the feel at impact of the resulting golf ball is improved.

Examples of the metal ion that neutralizes at least a part of the carboxyl group of the (a1) binary ionomer resin and / or (a2) the ternary ionomer resin include monovalent metal ions such as sodium, potassium, and lithium. Divalent metal ions such as magnesium, calcium, zinc, barium and cadmium; trivalent metal ions such as aluminum; and other ions such as tin and zirconium. The (a1) binary ionomer resin and the (a2) ternary ionomer resin are formed by at least one metal ion selected from the group consisting of Na ⁺ , Mg ²⁺ , Ca ²⁺ , and Zn ^2+. It is preferable that they are summed.

The neutralization degree of the carboxyl group in the (a1) binary ionomer resin and (a2) ternary ionomer resin is preferably 50 mol% or more, more preferably 60 mol% or more, and still more preferably 80 mol%. As described above, it is particularly preferably 100 mol%. If the degree of neutralization is 50 mol% or more, the resilience and durability of the resulting golf ball will be good. The neutralization degree of the carboxyl group of the ionomer resin can be determined by the following formula.
Degree of neutralization of ionomer resin (mol%) = 100 × number of moles of neutralized carboxyl groups in copolymer / total number of moles of carboxyl groups in copolymer

  The (a1) binary ionomer resin and (a2) ternary ionomer resin may be pre-neutralized ionomer resins, olefins, and α, β- having 3 to 8 carbon atoms. Binary copolymer with unsaturated carboxylic acid and / or ternary copolymer of olefin, C3-C8 α, β-unsaturated carboxylic acid and α, β-unsaturated carboxylic acid ester And (E) a metal compound to be described later may be used in combination. In addition, (a1) binary ionomer resin and (a2) ternary ionomer resin may be used alone or in combination of two or more.

  Examples of the (a1) binary ionomer resin include Himiran (registered trademark) 1555 (Na), 1557 (Zn), 1605 (Na), 1706 (Zn), 1707 (Na), AM7311 (Mg), and AM7329 (Zn). ) (Mitsui DuPont Polychemical Co., Ltd.); Surlyn (registered trademark) 8945 (Na), 9945 (Zn), 8140 (Na), 8150 (Na), 9120 (Zn), 9150 (Zn), 6910 (Mg) ), 6120 (Mg), 7930 (Li), 7940 (Li), AD8546 (Li) (manufactured by DuPont); Iotech (registered trademark) 8000 (Na), 8030 (Na), 7010 (Zn), 7030 (Zn) ) (Manufactured by ExxonMobil Chemical Co., Ltd.).

  Examples of the (a2) ternary ionomer resin include Himiran AM7327 (Zn), 1855 (Zn), 1856 (Na), AM7331 (Na) (manufactured by Mitsui DuPont Polychemical Co., Ltd.); Surlyn 6320 (Mg), 8120 (Na), 8320 (Na), 9320 (Zn), 9320W (Zn), HPF1000 (Mg), HPF2000 (Mg) (manufactured by DuPont); Iotech 7510 (Zn), 7520 (Zn) (manufactured by ExxonMobil Chemical Co., Ltd.) ) And the like.

  Examples of the binary copolymer include Nukurel (registered trademark) N1050H, N2050H, N1110H, N0200H, N1560, N2060 (manufactured by Mitsui DuPont Polychemical Co., Ltd.); Primacor (registered trademark) 5980I (manufactured by Dow Chemical Company) Etc. Examples of the ternary copolymer include Nucrel AN4318, AN4319 (Mitsui / DuPont Polychemical), Primacol AT310, AT320 (Dow Chemical). Na, Zn, Li, Mg, etc. described in parentheses after the trade name indicate the metal species of these neutralized metal ions.

  The golf ball resin composition may contain a thermoplastic resin other than the (A) olefin ionomer resin as a resin component. In this case, the content of the (A) olefin ionomer resin in the resin component is preferably 50% by mass or more, more preferably 55% by mass or more, and further preferably 65% by mass or more. It is also preferable to contain only the (A) olefinic ionomer resin as the resin component.

  Examples of the other thermoplastic resins include thermoplastic olefin copolymers, thermoplastic polyurethanes, thermoplastic polyamides, thermoplastic styrene resins, thermoplastic polyesters, thermoplastic acrylic resins (polyacrylic acid, polymethacrylic acid, poly Acrylonitrile), thermoplastic polyolefins (polyethylene, polypropylene, polyisoprene, etc.), thermoplastic polydienes (polybutadiene, etc.), and thermoplastic resins such as thermoplastic polyethers. Further, those obtained by modifying these thermoplastic resins with chlorine, bromine, maleic anhydride, ammonia or the like can also be used.

[(B) Modified nanocellulose]
The resin composition for golf balls contains (B) modified nanocellulose. The reason why lamellar crystals are generated on the outer periphery of the modified nanocellulose during molding is considered as follows. (B) The modified nanocellulose is excellent in adhesion (adhesiveness) with the (A) olefin ionomer resin since a hydrophobic group is introduced. Here, at the time of molding such as injection molding, (A) the olefin ionomer resin flows around (B) the modified nanocellulose. At this time, in the molecular chain of (A) the olefin ionomer resin, the part in contact with (B) the modified nanocellulose is pulled by (B) the modified nanocellulose. Therefore, it is considered that (B) the modified nanocellulose is surrounded by (A) shearing stress acting on the molecular chain of the olefinic ionomer resin to produce stretched crystals.

  (B) The nanocellulose constituting the modified nanocellulose is a material containing cellulose fibers (wood, lawn, fallen leaves, cotton, hemp, etc.), and the cellulose fibers contained therein are unraveled to the nano size. Yes, there are cellulose nanofibers and cellulose nanocrystals.

  The cellulose nanofibers can be obtained by mechanically opening cellulose fibers using a refiner or a beater. The average fiber diameter of the cellulose nanofiber is preferably 4 nm or more, preferably 200 nm or less, more preferably 150 nm or less, and still more preferably 100 nm or less. Although the average fiber length of the said cellulose nanofiber is not specifically limited, Usually, it is about 1 micrometer-10 micrometers.

  The cellulose nanocrystal is a crystal obtained by hydrolyzing cellulose fiber with an acid (sulfuric acid, hydrochloric acid, etc.). The average crystal width of the cellulose nanocrystal is preferably 4 nm or more, more preferably 10 nm or more, preferably 50 nm or less, more preferably 30 nm or less, and further preferably 20 nm or less. The average crystal length of the cellulose nanocrystal is preferably 25 nm or more, more preferably 100 nm or more, preferably 500 nm or less, more preferably 200 nm or less.

  The average fiber diameter, average fiber length, average crystal width, and average crystal length are determined by observing nanocellulose with an electron microscope, measuring 50 or more nanocelluloses in the field of view, and obtaining an average value.

  The (B) modified nanocellulose is at least one selected from the group consisting of an alkyl group, an alkenyl group, an alkylene group, an alkenylene group, and an arylene group, wherein at least a part of hydroxyl groups of the cellulose constituting the nanocellulose is included. It is substituted with a substituent containing a hydrophobic group.

  The alkyl group may be linear, branched or cyclic. The alkyl group preferably has 1 or more carbon atoms, more preferably 2 or more, still more preferably 4 or more, preferably 30 or less, more preferably 25 or less, and still more preferably 18 or less. 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, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group. , Hexadecyl group, heptadecyl group, octadecyl group, adamantyl group, cyclohexyl group and the like.

  The alkenyl group may be linear, branched or cyclic. The number of carbon atoms of the alkenyl group is preferably 2 or more, more preferably 3 or more, still more preferably 4 or more, preferably 30 or less, more preferably 25 or less, and still more preferably 18 or less. As the alkenyl group, vinyl group, allyl group, butenyl group, pentenyl group, hexenyl group, heptenyl group, octenyl group, nonenyl group, decenyl group, undecenyl group, dodecenyl group, tridecenyl group, tetradecenyl group, pentadecenyl group, hexadecenyl group , Heptadecenyl group, octadecenyl group and the like.

  The alkylene group may be linear, branched or cyclic. The alkylene group preferably has 1 or more carbon atoms, more preferably 2 or more, still more preferably 4 or more, preferably 30 or less, more preferably 25 or less, and still more preferably 18 or less. Examples of the alkyl group include methylene, ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene, dodecylene, tridecylene, tetradecylene, pentadecylene. , Hexadecylene group, heptadecylene group, octadecylene group and the like.

  The alkenylene group may be any of linear, branched and cyclic. The alkenylene group preferably has 2 or more carbon atoms, more preferably 3 or more, still more preferably 4 or more, preferably 30 or less, more preferably 25 or less, and still more preferably 18 or less. Examples of the alkenylene group include a vinylene group, a propenylene group, a butenylene group, a pentenylene group, a hexenylene group, a heptenylene group, an octenylene group, a nonenylene group, a decenylene group, an undecenylene group, a dodecenylene group, a tridecenylene group, a hexadecenylene group, a pentadecenylene group, and a pentadecenylene group. , Heptadecenylene group, octadecenylene group and the like.

  The alkyl group, alkenyl group, alkylene group and alkenylene group may have an aromatic ring structure. As an aromatic ring structure, a benzene ring; a condensed benzene ring such as a naphthalene ring, anthracene ring, phenanthrene ring, pyrene ring or biphenylene ring; a non-benzene aromatic ring such as a tropylium ring or cyclopropenium ring; a pyridine ring, a pyrimidine ring, Examples include heteroaromatic rings such as a pyrrole ring, a furan ring, and a thiophene ring.

  The arylene group preferably has 6 or more carbon atoms, more preferably 7 or more, still more preferably 8 or more, preferably 30 or less, more preferably 25 or less, and still more preferably 18 or less. Examples of the arylene group include a phenylene group and a naphthylene group.

  The substituent containing the hydrophobic group preferably has a total number of atoms of 95 or less, more preferably 80 or less, and still more preferably 71 or less.

  In the (B) modified nanocellulose, the ratio of hydroxyl group hydrogen in the cellulose is preferably 5 mol% or more, more preferably 20 mol% or more, and even more preferably 30 mol% or more. 90 mol% or less, more preferably 85 mol% or less, still more preferably 80 mol% or less. If the said ratio is 5 mol% or more, it becomes easy to produce | generate a lamellar crystal in the outer periphery of (B) modified | denatured nanocellulose, and the resilience of the member formed from the resin composition for golf balls improves more. Moreover, if the said ratio is 90 mol% or less, the rigidity derived from the cyclic polyacetal structure intrinsic | native to a cellulose will be maintained, and the resin composition for golf balls will become high resilience.

  The (B) modified nanocellulose is preferably one in which at least a part of the hydroxyl group hydrogen contained in the cellulose constituting the nanocellulose is substituted with a substituent represented by the following formula (1).

In the formula (1), R represents an alkylene group, an alkenylene group, an arylene group, an alkylene group containing an aromatic ring structure, or an alkenylene group containing an aromatic ring structure. X represents halogen, vinyl group (—CH═CH ₂ ), ethynyl group (—C≡CH), azide group (—N ₃ ), amino group (—NH ₂ ), thiol group (—SH), sulfide group ( -SR ¹ ), disulfide group (—S—S—R ² ), maleimide group (the following formula (2)), phthalimide group (the following formula (3)), 5-norbornene-2,3-dicarboximide group ( The following formula (4)), -Op-toluenesulfonyl group (following formula (5)), -O-methanesulfonyl group (following formula (6)), or -O-benzenesulfonyl group (following formula (7) )). In the formulas (1) to (7), * represents a bond.

  The alkylene group in formula (1) may be linear, branched or cyclic. The alkylene group preferably has 2 or more carbon atoms, more preferably 3 or more, still more preferably 4 or more, preferably 30 or less, more preferably 25 or less, and still more preferably 18 or less.

  The alkenylene group in the formula (1) may be linear, branched or cyclic. The alkenylene group preferably has 1 or more carbon atoms, more preferably 2 or more, still more preferably 4 or more, preferably 30 or less, more preferably 25 or less, and still more preferably 18 or less.

  The number of carbon atoms of the arylene group in the formula (1) is preferably 6 or more, more preferably 7 or more, still more preferably 8 or more, preferably 30 or less, more preferably 25 or less, and still more preferably 18 or less. .

  The aromatic ring structure of the alkylene group or alkenylene group in the formula (1) includes a benzene ring; a condensed benzene ring such as a naphthalene ring, an anthracene ring, a phenanthrene ring, a pyrene ring, or a biphenylene ring; a tropylium ring, a cyclopropenium ring, or the like Non-benzene aromatic rings; heteroaromatic rings such as pyridine ring, pyrimidine ring, pyrrole ring, furan ring, and thiophene ring.

  R in the formula (1) may have a graft chain. Examples of the graft chain include polymers of olefin monomers, styrene monomers and / or acrylic monomers. The number of repeating units of the polymer is preferably 10 or more, preferably 100 or less, and more preferably 30 or less.

  Examples of the halogen in the formula (1) include fluorine, chlorine, bromine and iodine.

Examples of R ¹ of the sulfide group and R ² of the disulfide group in the formula (1) include an alkyl group (1 to 30 carbon atoms) and an alkenyl group (2 to 30 carbon atoms). These alkyl groups and alkenyl groups may have an aromatic ring structure. When X in Formula (1) is a sulfide group or a disulfide group, the substituent represented by Formula (1) may form a sulfide bond or a disulfide bond with other substituents.

  R in the formula (1) is preferably an alkylene group or an alkenylene group. X in the formula (1) is preferably a halogen, an azide group or an amino group.

The (B) modified nanocellulose can be obtained by reacting nanocellulose and a modifying agent, or reacting cellulose and a modifying agent and then opening the fiber. The modifier includes at least one hydrophobic group selected from the group consisting of an alkyl group, an alkenyl group, an alkylene group, an alkenylene group, and an arylene group, and has a chemical structure capable of reacting with a hydroxyl group of cellulose. Things can be used. As the chemical structure capable of reacting with the hydroxyl group of cellulose, a carboxyl group, an acid anhydride group (—CO—O—CO—), a carboxylic acid halide (—COX ¹ (X ¹ = chlorine, bromine, iodine)), a halogen group ^(-X 1), include epoxy group.

  As the modifying agent, a compound represented by the following formula (8) or (9) is preferable.

  R in the formulas (8) and (9) represents an alkylene group, an alkenylene group, an arylene group, an alkylene group containing an aromatic ring structure, or an alkenylene group containing an aromatic ring structure. In the formula (9), a plurality of R may be the same or different. X in the formula (8) is halogen, vinyl group, ethynyl group, azide group, amino group, thiol group, sulfide group, disulfide group, maleimide group, phthalimide group, 5-norbornene-2,3-dicarboximide group , -Op-toluenesulfonyl group, -O-methanesulfonyl group, or -O-benzenesulfonyl group. Y in the formulas (8) and (9) represents chlorine, bromine, iodine, a hydroxyl group, -Op-toluenesulfonyl group, -O-methanesulfonyl group, -O-benzenesulfonyl group.

  Y in the formulas (8) and (9) is preferably chlorine. R in the formulas (8) and (9) is preferably an alkylene group, an alkenylene group or an alkylene group containing an aromatic ring structure. X in the formula (8) is preferably a halogen (chlorine, bromine), a vinyl group, a maleimide group, a phthalimide group, or a 5-norbornene-2,3-dicarboximide group.

  Examples of the modifier include monochloroacetyl chloride, monobromoacetyl chloride, 3-chloropropionyl chloride, 3-bromopropionyl chloride, 4-chlorobutyroyl chloride, 4-bromobutyroyl chloride, 5-chloropentanoyl chloride, 6- Bromohexanoyl chloride, 7-bromoheptanoyl chloride, 8-bromooctanoyl chloride, 9-bromononanoyl chloride, 10-bromodecanoyl chloride, 11-bromoundecanoyl chloride, 4- (chloromethyl) benzoyl chloride 3-butenoyl chloride, 4-pentenoyl chloride, 3-methylpentenoyl chloride, 5-hexenoyl chloride, 10-undecenoyl chloride, 3-cyclopentene-1-carboxylic acid chloride, 5-norbornene- - such as carboxylic acid chlorides and the like.

  The temperature at which nanocellulose or cellulose and the modifier are reacted may be appropriately adjusted according to the modifier, but is preferably 20 ° C to 200 ° C.

  A commercially available product may be used as the (B) modified nanocellulose. Examples of the modified nanocellulose (B) include T-NP109 and T-NP132 manufactured by Starlight PMC.

  The blending amount of the (B) modified nanocellulose is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and still more preferably 5 parts by mass or more with respect to 100 parts by mass of the (A) olefin ionomer resin. Yes, 60 parts by mass or less is preferable, more preferably 40 parts by mass or less, and still more preferably 30 parts by mass or less. If the blending amount of the (B) modified nanocellulose is 1 part by mass or more, the resilience of the golf ball resin composition is further improved, and if it is 60 parts by mass or less, the golf ball resin composition becomes too hard. Thus, the feel at impact of the obtained golf ball is improved.

[(C) Amphoteric surfactant]
The resin composition for golf balls may contain (C) an amphoteric surfactant in addition to the components (A) and (B). (C) The amphoteric surfactant is considered to be incorporated into the ion aggregate of (A) the olefin ionomer resin and weaken the restriction of the main chain by the ion aggregate. Due to this action, the golf ball resin composition of the present invention has higher molecular chain mobility and higher flexibility.

  The (C) amphoteric surfactant is not particularly limited as long as it contains a cationic site and an anionic site in the molecule and has a function of reducing surface tension by dissolving in water. Examples of amphoteric surfactants include betaine type amphoteric surfactants such as alkylbetaine type, amide betaine type, imidazolium betaine type, alkylsulfobetaine type, and amide sulfobetaine type; amide amino acid type amphoteric surfactants, alkylamino Fatty acid salt; alkylamine oxide; β-alanine type amphoteric surfactant, glycine type amphoteric surfactant; sulfobetaine type amphoteric surfactant; phosphobetaine type amphoteric surfactant. (C) Amphoteric surfactants may be used alone or in combination of two or more.

  Specific examples of amphoteric surfactants include dimethyl lauryl betaine, oleyl dimethylaminoacetic acid betaine (oleyl betaine), dimethyl oleyl betaine, dimethyl stearyl betaine, stearyl dihydroxymethyl betaine, stearyl dihydroxyethyl betaine, lauryl dihydroxymethyl betaine, lauryl dihydroxyethyl. Betaine, myristyl dihydroxymethyl betaine, behenyl dihydroxymethyl betaine, palmityl dihydroxyethyl betaine, oleyl dihydroxymethyl betaine, coconut oil fatty acid amide propyl betaine, lauric acid amide alkyl betaine, 2-alkyl-N-carboxyalkyl imidazolinium betaine, laurin Acid amide alkyl hydroxy sulfobetaine, coconut oil fatty acid amide di Alkylhydroxyalkylsulfobetaine, N-alkyl-β-aminopropionate, N-alkyl-β-iminodipropionate, alkyldiaminoalkylglycine, alkylpolyaminoalkylglycine, alkylamino fatty acid sodium, N, N-dimethyloctyl Examples thereof include amine oxide, N, N-dimethyllaurylamine oxide, N, N-dimethylstearylamine oxide, and the like.

  (C) The compounding amount of the amphoteric surfactant is preferably 0.5 parts by mass or more, more preferably 1.0 part by mass or more, further preferably 5 with respect to 100 parts by mass of the (A) olefin ionomer resin. 0.0 part by mass or more, preferably 60 parts by mass or less, more preferably 30 parts by mass or less, and still more preferably 15 parts by mass or less. (C) If the amount of the amphoteric surfactant is within the above range, the surfactant molecules are easily incorporated into the ionomer resin ion aggregate, the mobility of the molecular chain is increased, and the flexibility is maintained. This is because the resilience increases.

[(D) Fatty acid]
The golf ball resin composition may further contain (D) a fatty acid. (D) By containing a fatty acid, the fluidity | liquidity of the resin composition for golf balls improves, and formation of a thin layer becomes easy. The (D) fatty acid is not particularly limited, and either saturated fatty acid or unsaturated fatty acid can be used. Further, the (D) fatty acid may be a linear fatty acid or a fatty acid having a branched chain. Said (D) fatty acid may be used independently and may use 2 or more types together.

  The (D) fatty acid preferably has 3 or more carbon atoms, more preferably 8 or more, still more preferably 16 or more, preferably 30 or less, more preferably 28 or less, and still more preferably 24 or less.

  Examples of the saturated fatty acid include butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, octadecanoic acid Nonadecanoic acid, icosanoic acid, henicosanoic acid, docosanoic acid, tricosanoic acid, tetracosanoic acid, pentacosanoic acid, hexacosanoic acid, heptacosanoic acid, octacosanoic acid, nonacosanoic acid, triacontanoic acid and the like.

  Unsaturated fatty acids include butenoic acid, pentenoic acid, hexenoic acid, heptenoic acid, octenoic acid, nonenic acid, decenoic acid, undecenoic acid, dodecenoic acid, tridecenoic acid, tetradecenoic acid, pentadecenoic acid, hexadecenoic acid, heptadecenoic acid, octadecenoic acid , Nonadecenoic acid, icosenoic acid, henicosenoic acid, docosenoic acid, tricosenoic acid, tetracosenoic acid, pentacosenoic acid, hexacosenoic acid, heptacosenoic acid, octacosenoic acid, nonacenoic acid, triacontenoic acid and the like.

  The blending amount of the (D) fatty acid is preferably 5 parts by mass or more, more preferably 30 parts by mass or more, and still more preferably 50 parts by mass or more with respect to 100 parts by mass of the (A) olefin ionomer resin. The amount is preferably not more than part by mass, more preferably not more than 150 parts by mass, and still more preferably not more than 120 parts by mass. (D) If the amount of fatty acid is 5 parts by mass or more, the fluidity of the golf ball resin composition is further improved, and if it is 180 parts by mass or less, fatty acid bleed-out can be suppressed.

[(E) metal compound]
The golf ball resin composition may further contain (E) a metal compound. (E) By containing a metal compound, the neutralization degree of (A) olefin ionomer resin can be further raised, and the resilience of the resin composition for golf balls is further improved.

  The (E) metal compound is not particularly limited as long as it can neutralize a carboxyl group. For example, magnesium hydroxide, zinc hydroxide, calcium hydroxide, sodium hydroxide, lithium hydroxide, Metal hydroxides such as potassium hydroxide and copper hydroxide; metal oxides such as magnesium oxide, calcium oxide, zinc oxide and copper oxide; magnesium carbonate, zinc carbonate, calcium carbonate, sodium carbonate, lithium carbonate, potassium carbonate, etc. A metal carbonate is mentioned.

  Moreover, a basic fatty acid metal salt can also be used as said (E) metal compound. Basic fatty acid metal salts include basic magnesium laurate, basic calcium laurate, basic zinc laurate, basic magnesium myristate, basic calcium myristate, basic zinc myristate, basic magnesium palmitate, base Basic calcium palmitate, basic zinc palmitate, basic magnesium oleate, basic calcium oleate, basic zinc oleate, basic magnesium stearate, basic calcium stearate, basic zinc stearate, basic 12- Examples include magnesium hydroxystearate, basic calcium 12-hydroxystearate, basic zinc zinc 12-hydroxystearate, basic magnesium behenate, basic calcium behenate, basic zinc behenate, etc. It is.

  (E) The compounding quantity of a metal compound should just adjust suitably according to the neutralization degree of (A) olefin type ionomer resin, and the equivalent ratio mentioned later.

  In the golf ball resin composition of the present invention, the equivalent ratio of metal ions in the golf ball resin composition to the carboxy groups of the components (A) and (D) (equivalents of metal ions / equivalents of carboxy groups) is 0.5 or more, preferably 0.8 or more, more preferably 1.0 or more, 2.5 or less, more preferably 1.8 or less, still more preferably 1.4 or less. . When the equivalent ratio is 0.5 or more, the resilience of the golf ball resin composition is further improved, and when the equivalent ratio is 2.5 or less, the golf ball resin composition does not become too hard and the resulting golf ball is hit. A feeling becomes good.

  In addition, the equivalent of the said carboxy group is the total number of moles of the carboxy group which (A) component and (D) component have. The equivalents of the metal ions are the product of the number of moles of metal ions of the component (A) and the valence of metal ions, and (E) the number of moles of metal ions of the metal compound and the valence of the metal ions. Is the sum of products.

  The resin composition for a golf ball of the present invention further includes a pigment component such as a white pigment (for example, titanium oxide), a blue pigment, a weight adjuster, a dispersant, an anti-aging agent, an ultraviolet absorber, a light stabilizer, and a fluorescent material. Or additives, such as a fluorescent whitening agent, can be contained. Examples of the weight adjuster include inorganic fillers such as zinc oxide, barium sulfate, calcium carbonate, magnesium oxide, tungsten powder, and molybdenum powder.

  The melt flow rate (190 ° C., 2.16 kg load) of the resin composition for golf balls is preferably 0.1 g / 10 min or more, more preferably 0.5 g / 10 min or more, further preferably 1.0 g / 10 min or more. It is preferably 60 g / 10 min or less, more preferably 30 g / 10 min or less, still more preferably 15 g / 10 min or less. When the melt flow rate is 0.1 g / 10 min or more, the fluidity is good and a thin layer can be formed. When the melt flow rate is 60 g / 10 min or less, the durability of the obtained golf ball becomes better.

[Production method]
The resin composition for golf balls of the present invention includes, for example, (A) an olefin ionomer resin, (B) a modified nanocellulose, and (C) an amphoteric surfactant, (D) a fatty acid, and (E) a metal as necessary. The compound and other additives can be obtained by melt mixing. For the melt mixing, a kneader or an extruder (a single screw extruder, a twin screw extruder, a twin screw single screw extruder, or the like) can be used.

[Golf ball]
The golf ball of the present invention has a constituent member formed from the golf ball resin composition. As described above, by using the golf ball resin composition, it is possible to form a constituent member having low hardness and high resilience. A golf ball having such a constituent member has a good shot feeling and high resilience.

  The structure of the golf ball is not particularly limited. For example, a two-piece golf ball having a single-layer core and a cover that covers the core; a core and one or more intermediate layers that cover the core; and the intermediate layer that covers the core And multi-piece golf balls (three-piece golf balls, four-piece golf balls, five-piece golf balls, etc.) having a cover to be used.

  The slab hardness (H) of the component member is preferably 40 or more in Shore D hardness, more preferably 43 or more, still more preferably 46 or more, preferably 75 or less, more preferably 72 or less, still more preferably 67 or less. Particularly preferably, it is 65 or less. If the slab hardness is within the above range, the golf ball feels better.

The bending stiffness of the component (R) is ^preferably not less than 500kgf / cm 2 (49.0MPa), and more preferably 800kgf ^/ cm 2 (78.4MPa) or more, more preferably 1,200kgf ^/ cm 2 (118MPa) 20,000 kgf / cm ² (1,961 MPa) or less is preferable, more preferably 13,000 kgf / cm ² (1,275 MPa) or less, and even more preferably 9,000 kgf / cm ² (882 MPa) or less. . If the bending rigidity is 500 kgf / cm ² or more, the ball deformation at the time of hitting becomes small, and the energy of hitting can be efficiently converted into acceleration of the ball, so that the golf ball becomes highly repulsive. Further, if the bending rigidity is 20,000 kgf / cm ² or less, the flexibility becomes good, the impact at the time of hitting can be suppressed, and a golf ball having a good shot feeling can be obtained.

  The ratio (H / R) of the slab hardness (H) to the bending rigidity (R) is preferably 0.002 or more, more preferably 0.004 or more, still more preferably 0.005 or more, and 0.100. The following is preferable, more preferably 0.080 or less, and still more preferably 0.056 or less. When the ratio (H / R) is 0.002 or more, the resilience of the constituent member is further improved. When the ratio (H / R) is 0.100 or less, the constituent member is not too hard, and the golf ball feels good. In addition, the slab hardness and bending rigidity of a structural member are the measured values about the slab produced on the same conditions as the said structural member when using the said resin composition for golf balls.

  The modified nanocellulose (B) contained in the component formed from the golf ball resin composition has a polyethylene chain lamellar crystal having a maximum length of 11 nm or more in at least a part of the outer periphery. Preferably it is present. Thus, the presence of large polyethylene chain lamellar crystals on the outer periphery of (B) modified nanocellulose improves the resilience of the constituent members, resulting in high resilience of the resulting golf ball.

  In addition, it is sufficient that at least one (B) modified nanocellulose having a polyethylene chain lamellar crystal on the outer periphery is present. Further, in the modified nanocellulose (B) in which a polyethylene chain lamellar crystal is present at the outer peripheral edge, the lamellar crystal is preferably present in 10% or more of the outer peripheral edge, more preferably 40% or more, and further preferably 70%. That's it.

  The method for producing the constituent member is not particularly limited, but after the resin composition for a golf ball is melt-molded at a material temperature of 120 ° C. to 240 ° C., it is cooled to a material temperature of 100 ° C. or less at a cooling rate of 60 ° C./s. It is preferable to do. Thus, it can suppress that the lamellar crystal | crystallization of the polyethylene chain produced | generated in the outer periphery of (B) modified | denatured nanocellulose by melt-cooling after melt molding lose | disappears by the residual heat after shaping | molding completion.

  The material temperature during the melt molding is preferably 130 ° C or higher, more preferably 150 ° C or higher, 200 ° C or lower, more preferably 190 ° C or lower. The cooling rate is preferably 60 ° C./s or more, more preferably 100 ° C./s or more. The cooling temperature is preferably 80 ° C. or lower, more preferably 30 ° C. or lower.

  When forming a constituent member by injection molding using the golf ball resin composition, the nozzle temperature is set to 120 ° C. to 240 ° C., and the mold temperature (cavity surface temperature) is set to 100 ° C. or lower (preferably 50 ° C. or lower, More preferably, it may be 20 ° C. or less.

  The member formed from the golf ball resin composition may be any of a core, an intermediate layer, and a cover, but an intermediate layer is preferable. The golf ball may be made of a conventionally known material other than the components formed from the golf ball resin composition.

  A known rubber composition (hereinafter sometimes simply referred to as “core rubber composition”) may be used for the core. For example, a rubber composition containing a base rubber, a co-crosslinking agent, and a crosslinking initiator. Can be formed by hot pressing.

  As the base rubber, it is particularly preferable to use a high-cis polybutadiene having a cis bond advantageous for rebound of 40% by mass or more, preferably 70% by mass or more, and more preferably 90% by mass or more. The co-crosslinking agent is preferably an α, β-unsaturated carboxylic acid having 3 to 8 carbon atoms or a metal salt thereof, more preferably a metal salt of acrylic acid or a metal salt of methacrylic acid. 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. As the crosslinking initiator, an organic peroxide is preferably used. Specifically, dicumyl peroxide, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-di (t-butylperoxy) Organic peroxides such as hexane and di-t-butyl peroxide can be mentioned, and among them, dicumyl peroxide is preferably used. The amount of the crosslinking 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 100 parts by mass of the base rubber. 2 parts by mass or less.

  The rubber composition for a core may further contain an organic sulfur compound. As the organic sulfur compound, diphenyl disulfides, thiophenols, and thionaphthols can be preferably used. The compounding amount of the organic sulfur compound is preferably 0.1 parts by mass or more, more preferably 0.3 parts by mass or more, and preferably 5.0 parts by mass or less with respect to 100 parts by mass of the base rubber. Preferably it is 3.0 mass parts or less. The core rubber composition may further contain a carboxylic acid and / or a salt thereof. The carboxylic acid and / or salt thereof is preferably a carboxylic acid having 1 to 30 carbon atoms and / or a salt thereof. The compounding quantity of carboxylic acid and / or its salt is 1 to 40 mass parts with respect to 100 mass parts of base rubber.

  In addition to the base rubber, co-crosslinking agent, cross-linking initiator, and organic sulfur compound, the core rubber composition further contains a weight adjusting agent such as zinc oxide and barium sulfate, an anti-aging agent, and color powder as appropriate. Can be blended. The hot-press molding conditions for the core rubber composition 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 at 130 ° C. to 150 ° C. for 20 minutes. After heating for 40 minutes for 40 minutes, it is preferable to heat at 160 ° C. to 180 ° C. for 5 minutes to 15 minutes.

  Examples of the intermediate layer material include thermoplastic resins such as polyurethane resins, ionomer resins, polyamide resins, and polyethylene; thermoplastic elastomers such as styrene elastomers, polyolefin elastomers, polyurethane elastomers, and polyester elastomers; and cured products of rubber compositions. It is done. Here, examples of the ionomer resin include those obtained by neutralizing at least a part of carboxyl groups in a copolymer of ethylene and α, β-unsaturated carboxylic acid with metal ions, or ethylene and α, β-unsaturated. What neutralized at least one part of the carboxyl group in the ternary copolymer of saturated carboxylic acid and (alpha), (beta)-unsaturated carboxylic acid ester with a metal ion is mentioned. The intermediate layer may further contain a specific gravity adjusting agent such as barium sulfate or tungsten, an antiaging agent, or a pigment.

  The method for forming the intermediate layer is not particularly limited. For example, the method for forming the intermediate layer composition into a half-shell-shaped half shell in advance, wrapping the sphere using the two, and pressure-molding, or Examples thereof include a method of wrapping a sphere by injection molding the intermediate layer composition directly onto the sphere.

  When the intermediate layer is formed by injection molding the intermediate layer composition onto a sphere, it is preferable to use a mold having hemispherical cavities as the upper and lower molds for molding. The intermediate layer can be formed by injection molding by projecting a hold pin, inserting a coated sphere and holding it, and then injecting a heat-melted intermediate layer composition and cooling it. it can.

  When the intermediate layer is formed by the compression molding method, the half shell can be molded by either the compression molding method or the injection molding method, but the compression molding method is preferred. The conditions for compression molding the intermediate layer composition into a half shell include, for example, a pressure of 1 MPa or more and 20 MPa or less and −20 ° C. or higher and + 70 ° C. with respect to the flow start temperature of the intermediate layer composition. The following molding temperatures can be mentioned. By setting the molding conditions, a half shell having a uniform thickness can be molded. As a method for forming the intermediate layer using a half shell, for example, a method in which a sphere is covered with two half shells and compression-molded can be mentioned. The conditions for compression-molding the half shell into the intermediate layer are, for example, −20 ° C. or higher and + 70 ° C. with respect to the flow start temperature of the intermediate layer composition at a molding pressure of 0.5 MPa or higher and 25 MPa or lower. The following molding temperatures can be mentioned. By setting the molding conditions, an intermediate layer having a uniform thickness can be molded.

The molding temperature means the maximum temperature that the surface of the concave portion of the lower mold reaches between the mold clamping and the mold opening. Moreover, the flow start temperature of the composition is a pellet-shaped thermoplastic resin composition using “Flow Tester CFT-500” manufactured by Shimadzu Corporation, plunger area: 1 cm ² , DIE LENGTH: 1 mm, DIE DIA: 1 mm, Load: 588.399 N, start temperature: 30 ° C., temperature increase rate: 3 ° C./min.

  The thickness of the intermediate layer is preferably 0.3 mm or more, more preferably 0.4 mm or more, further preferably 0.5 mm or more, preferably 2.5 mm or less, more preferably 2.4 mm or less, and still more preferably. 2.3 mm or less. In the case of a plurality of intermediate layers, the total thickness of the plurality of intermediate layers is preferably in the above range.

  The cover material is not particularly limited, and examples thereof include ionomer resin, polyurethane, polyamide, polyester, polystyrene, and the like, and polyurethane and ionomer resin are preferable.

  A specific example of the cover material is exemplified by a trade name, which is commercially available from Mitsui DuPont Polychemical Co., Ltd. under the trade name “Himilan (registered trademark)” from Ionomer Resin, BASF Japan Co., Ltd. Thermoplastic polyurethane elastomer marketed under the trade name "Elastollan (registered trademark)", Thermoplastic polyamide elastomer marketed under the trade name "Pebax (registered trademark)" from Arkema Co., Ltd. Toray DuPont Co., Ltd. A thermoplastic polyester elastomer marketed under the trade name “Hytrel®”, a thermoplastic styrene elastomer marketed under the trade name “Lavalon®” from Mitsubishi Chemical Corporation, or a product name “Primalloy”. List thermoplastic polyester elastomers that are commercially available in It can be. You may use the said cover material individually or in mixture of 2 or more types.

  In addition to the resin component described above, the cover includes a pigment component such as a white pigment (for example, titanium oxide), a blue pigment, and a red pigment, a specific gravity adjuster such as calcium carbonate and barium sulfate, a dispersant, an anti-aging agent, and an ultraviolet absorber. An agent, a light stabilizer, a fluorescent material, a fluorescent whitening agent, or the like may be contained as long as the performance of the cover is not impaired.

  Although the aspect which shape | molds a cover using the composition for a cover is not specifically limited, the aspect which directly inject-molds the composition for a cover on a core, or shape | molds a hollow shell-like shell from a composition for a cover, and a core And a method of compression molding by coating with a plurality of shells (preferably a method of molding a hollow shell-shaped half shell from a cover composition and coating a core with two half shells) Can do. The golf ball body in which the cover is molded is preferably taken out from the mold and subjected to surface treatment such as deburring, washing, and sandblasting as necessary. Moreover, a mark can be formed if desired.

  The thickness of the cover is preferably 4.0 mm or less, more preferably 3.0 mm or less, and still more preferably 2.0 mm or less. If the cover has a thickness of 4.0 mm or less, the resulting golf ball will have better resilience and feel at impact. The thickness of the cover is preferably 0.3 mm or more, more preferably 0.4 mm or more, and further preferably 0.5 mm or more. If the thickness of the cover is less than 0.3 mm, the durability and wear resistance of the cover may decrease.

  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, the dimple effect is difficult to obtain. Further, when the total number of dimples exceeds 500, the size of each dimple becomes small and it is difficult to obtain the dimple effect. The shape (plan view shape) of the dimple formed is not particularly limited, and a circular shape; a polygon such as a substantially triangular shape, a substantially square shape, a substantially pentagonal shape, or a substantially hexagonal shape; Alternatively, two or more kinds may be used in combination.

  The golf ball on which the cover is molded is preferably taken out of the mold and subjected to surface treatment such as deburring, washing, and sand blasting as necessary. Moreover, a coating film and a mark can also be formed if desired. The film thickness of the coating film is not particularly limited, but is preferably 5 μm or more, more preferably 7 μm or more, preferably 50 μm or less, more preferably 40 μm or less, and further preferably 30 μm or less. This is because when the film thickness is less than 5 μm, the coating tends to be worn away by continuous use, and when the film thickness exceeds 50 μm, the dimple effect is reduced and the flight performance of the golf ball is reduced.

  The diameter of the golf ball of the present invention is preferably 40 mm to 45 mm. The diameter is particularly preferably equal to or greater than 42.67 mm from the viewpoint that US Golf Association (USGA) standards are satisfied. In light of suppression of air resistance, the diameter is more preferably equal to or less than 44 mm, and particularly preferably equal to or less than 42.80 mm. The mass of the golf ball is preferably 40 g or more and 50 g or less. In light of attainment of great inertia, the mass is more preferably equal to or greater than 44 g, and particularly preferably equal to or greater than 45.00 g. In light of satisfying the USGA standard, the mass is particularly preferably equal to or less than 45.93 g.

  When the golf ball of the present invention has a diameter of 40 mm to 45 mm, the amount of compressive deformation (the amount of shrinkage of the golf ball in the compression direction) when the final load 1275N is applied from the state where the initial load 98N is applied is 2.0 mm or more. Preferably, it is 2.4 mm or more, more preferably 2.5 mm or more, most preferably 2.8 mm or more, and preferably 5.0 mm or less, 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 compressive deformation is 5.0 mm or less, the resilience increases.

  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 disposed outside the spherical core 2, and a cover 4 disposed outside the intermediate layer 3. A large number of dimples 41 are formed on the surface of the cover 4. Of the surface of the cover 4, a portion other than the dimples 41 is a land 42. And the said intermediate | middle layer 3 is formed from the said resin composition for golf balls.

  Hereinafter, the present invention will be described in detail by way of examples. However, the present invention is not limited to the following examples, and all modifications and embodiments without departing from the gist of the present invention are not limited thereto. Included in range.

[Evaluation method]
(1) Slab hardness (Shore D hardness)
Using the golf ball resin composition, a sheet having a thickness of about 2 mm was produced by injection molding and stored at 23 ° C. for 2 weeks. The nozzle temperature and mold temperature during injection molding were the same as the injection molding conditions when molding the component (intermediate layer). The hardness was measured using an automatic hardness tester (Higgle Burleys, Digitest II) in a state where three or more sheets were stacked so that the measurement substrate and the like were not affected. The detector used was “Shore D”.

(2) Flexural rigidity (kgf / cm ² )
A test piece having a thickness of about 2 mm, a width of 20 mm, and a length of 100 mm was produced by injection molding using the golf ball resin composition. The nozzle temperature and mold temperature during injection molding were the same as the injection molding conditions when molding the component (intermediate layer). The test piece was stored for 14 days at a temperature of 23 ± 2 ° C. and a relative humidity of 50 ± 5%. About the produced test piece, the load value at a bending angle of 3 ° and 12 ° was measured using an Olsen stiffness tester (manufactured by Toyo Seiki Seisakusho), the horizontal axis represents the bending angle (°), and the vertical axis represents the load scale. The readings were plotted and the slope of the straight line passing through these points was determined. The measurement conditions were a temperature of 23 ± 2 ° C., a relative humidity of 50 ± 5%, a bending speed of 60 ° / min, and a fulcrum distance of 50 mm. The bending rigidity was calculated by multiplying the value of the inclination by 8.7078 and dividing by the cube of the thickness (cm) of the test piece.

(3) Melt flow rate (MFR) (g / 10 min)
MFR was measured according to JIS K7210 (1999) using a flow tester (manufactured by Shimadzu Corporation, Shimadzu flow tester CFT-100C). The measurement was performed under the conditions of a measurement temperature of 190 ° C. and a load of 2.16 kg.

(4) Lamella crystals The abundance of lamellar crystals on the outer periphery of the filler (modified nanocellulose, unmodified nanocellulose, cotton fiber, aramid fiber, silica powder, nucleating agent) was measured by an image imaging method. Specifically, a micrograph (magnification: 10,000 times, field of view: 10 μm × 10 μm) was taken for a resin slab produced under the same molding conditions as the molding conditions of the constituent members. Next, the obtained micrograph was analyzed with image analysis software (Nikkiso Co., Ltd., Viewtrac (registered trademark)), and for all fillers present in the field of view, the length in the longitudinal direction and the presence of lamellar crystals at the outer periphery were confirmed. The presence or absence was confirmed. Based on the analysis results, the maximum length in the longitudinal direction of the lamella crystals and the abundance ratio of the lamella crystals were determined. The abundance of lamella crystals was calculated by the following formula.
[Abundance ratio of lamella crystals (%)] = 100 × [total length of the portions of the outer periphery of all fillers in the image that are in contact with the lamella crystals] ÷ [outside of all fillers in the image Total rim length].

(5) Compression deformation (mm)
The amount of deformation in the compression direction (the amount by which the golf ball shrinks in the compression direction) from when the initial load 98N was applied to the golf ball to when the final load 1275N was applied was measured.

(6) Coefficient of restitution A golf ball is made to collide with 198.4 g of a metal cylinder at a speed of 40 m / sec, and the speed of the cylinder and the golf ball before and after the collision is measured. The coefficient of restitution was calculated. The measurement was performed 12 pieces for each golf ball, and the average value was used as the coefficient of restitution of the golf ball.

(7) Feeling of hitting 10 amateur golfers (advanced players) performed an actual hitting test using a driver, and evaluated the feeling at the time of hitting according to the following criteria. Of the 10 evaluations, the highest evaluation was the shot feel of the golf ball.
Evaluation criteria Excellent: Less impact and good feeling.
Good: Normal.
Inferior: The impact is great and the feeling is bad.

[Production of golf balls]
(1) Production of Spherical Core A rubber composition for a core having the composition shown in Table 1 was kneaded with a kneading roll, and heated and pressed at 170 ° C. for 20 minutes in an upper and lower mold having a hemispherical cavity to obtain a diameter of 39.8 mm. A spherical core was obtained.

Polybutadiene rubber: “BR730 (cis bond content: 95% by mass)” manufactured by JSR Corporation
Zinc acrylate: Sigma Aldrich dicumyl peroxide: Tokyo Kasei Kogyo Thionaphthol: Tokyo Kasei Kogyo

(2) Preparation of intermediate layer (A) component and (C) component, (D) component, and (E) component are put into a kneader so that it may become the mixing | blending shown in Table 2, 3, 220 The mixture was kneaded at 15 ° C. for 15 minutes. Golf ball no. With respect to 1 to 20, 23 and 24, the component (B) or other filler component was then added, and further kneaded at 190 ° C. for 10 minutes to prepare a golf ball resin composition. The obtained golf ball resin composition was injection-molded on a spherical core to form an intermediate layer (thickness: 1.0 mm). Injection molding was performed under the conditions shown in Tables 2 and 3.

The materials used in Tables 2 and 3 are as follows.
Nukurel N1560: manufactured by Mitsui DuPont Polychemical Co., Ltd., ethylene-methacrylic acid copolymer (methacrylic acid content: 15% by mass, ethylene content: 85% by mass)
Nukurel AN4319: manufactured by Mitsui DuPont Polychemical Co., Ltd., ethylene-methacrylic acid-butyl methacrylate copolymer (methacrylic acid content: 8 mass%, ethylene content: 92 mass%)
Nukurel N2060: manufactured by Mitsui DuPont Polychemical Co., Ltd., ethylene-methacrylic acid copolymer (methacrylic acid content: 20% by mass, ethylene content: 80% by mass)
T-NP132: modified cellulose nanofiber (manufactured by Seiko PMC Co., Ltd., aggregate of cellulose nanofibers having a particle diameter of 20 μm to 50 μm, average fiber diameter of 4 nm to 200 nm, average fiber length of 0.1 μm to 50 μm, cellulose constituting cellulose nanofiber) In which at least a part of the hydrogen of the hydroxyl group of is substituted with the substituent represented by the formula (1))
T-NP109: manufactured by Seiko PMC Co., Ltd., modified cellulose nanofiber (aggregate of cellulose nanofiber having a particle size of 20 μm to 50 μm, average fiber diameter of 4 nm to 200 nm, average fiber length of 0.1 μm to 50 μm, cellulose constituting cellulose nanofiber In which at least a part of the hydrogen of the hydroxyl group of is substituted with the substituent represented by the formula (1))
Unmodified nanocellulose: Nippon Paper Industries KC Flock (registered trademark) W-250 (particle size 28-32 nm)
Cotton fiber: Cotton absorbent cotton manufactured by Kawamoto Sangyo Co., Ltd., with an average fiber length of 1 mm or less Aramid fiber: Teijin Industry, Twaron (registered trademark) (average fiber length 250 μm, average fiber diameter 10 μm)
Silica powder: manufactured by Nissan Chemical Industries, Snowtech OXS (particle size: 4-6 nm)
Carbon powder: manufactured by Nishina Material, graphene oxide nucleating agent: manufactured by ADEKA, NA-27
Oleyl betaine: A product obtained by removing moisture and salt from “Chembetaine OL” manufactured by Lubrizol Corporation Oleic acid: Magnesium hydroxide manufactured by Tokyo Chemical Industry Co., Ltd. Sodium hydroxide manufactured by Wako Pure Chemical Industries, Ltd. Sodium hydroxide manufactured by Wako Pure Chemical Industries, Ltd .: Sigma Aldrich calcium hydroxide: Tokyo Chemical Industry Co., Ltd.

(3) Preparation of cover Biaxial kneading type by adding 4 parts by mass of titanium oxide (A220, manufactured by Ishihara Sangyo Co., Ltd.) to 100 parts by mass of thermoplastic polyurethane elastomer (manufactured by BASF Japan, Elastollan (registered trademark) XNY85A). Mixing with an extruder, a pellet-shaped cover composition was prepared. The extrusion conditions for the cover composition were: screw diameter 45 mm, screw rotation speed 200 rpm, screw L / D = 35, and the formulation was heated to 160-230 ° C. at the die position of the extruder.

  At the time of molding the cover, a hold pin is projected, the sphere on which the intermediate layer is formed is thrown in and held, and the cover composition heated to 260 ° C. is injected into the mold clamped at a pressure of 80 tons in 0.3 seconds. After cooling for 30 seconds, the mold was opened and the golf ball was taken out (cover thickness 0.5 mm). The surface of the obtained golf ball main body was sandblasted and marked, and then a clear paint was applied and the paint was dried in an oven at 40 ° C. to obtain a golf ball.

  The evaluation results of each golf ball are shown in Tables 2 and 3. Further, in FIG. A photomicrograph of the intermediate layer 1 was shown. In FIG. Micrographs of 10 intermediate layers are shown. Golf ball no. As for 1-5, 12-20, 23, and 24, the intermediate | middle layer is formed from the resin composition for golf balls containing (A) olefin type ionomer resin and (B) modified nano cellulose. These golf balls are excellent in resilience and feel at impact. Golf ball no. In 6-11, 21 and 22, the golf ball resin composition constituting the intermediate layer does not contain (B) modified nanocellulose. These golf balls have poor resilience.

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

Claims (15)

(A) containing an olefinic ionomer resin and (B) modified nanocellulose,
The (B) modified nanocellulose is at least one selected from the group consisting of an alkyl group, an alkenyl group, an alkylene group, an alkenylene group and an arylene group, wherein at least a part of the hydroxyl groups of the cellulose constituting the nanocellulose has A golf ball resin composition substituted with a substituent containing a hydrophobic group. The (B) modified nanocellulose is one in which at least a part of the hydroxyl group hydrogen contained in the cellulose constituting the nanocellulose is substituted with a substituent represented by the following formula (1). Golf ball resin composition.
[In the formula (1), R represents an alkylene group, an alkenylene group, an arylene group, an alkylene group containing an aromatic ring structure, or an alkenylene group containing an aromatic ring structure. X is halogen, vinyl group, ethynyl group, azide group, amino group, thiol group, sulfide group, disulfide group, maleimide group, phthalimide group, 5-norbornene-2,3-dicarboximide group, -Op- It represents a toluenesulfonyl group, -O-methanesulfonyl group, or -O-benzenesulfonyl group. * Represents a bond. ]   The golf ball resin composition according to claim 1, wherein the modified nanocellulose (B) is a modified cellulose nanofiber.   The golf ball according to any one of claims 1 to 3, wherein a content of the (B) modified nanocellulose is 1 part by mass to 60 parts by mass with respect to 100 parts by mass of the (A) olefin ionomer resin. Resin composition.   The resin composition for golf balls according to any one of claims 1 to 4, wherein the melt flow rate (190 ° C, 2.16 kg load) is 0.1 g / 10 min to 60 g / 10 min.   The (A) olefinic ionomer resin is (a1) a metal ion neutralized product of a binary copolymer of an olefin and an α, β-unsaturated carboxylic acid having 3 to 8 carbon atoms, and / or (a2 6. A metal ion neutralized product of a terpolymer of an olefin, an α, β-unsaturated carboxylic acid having 3 to 8 carbon atoms and an α, β-unsaturated carboxylic acid ester. The golf ball resin composition according to claim 1. The (a1) binary copolymer metal ion neutralized product and (a2) ternary copolymer metal ion neutralized product are composed of Na ⁺ , Mg ²⁺ , Ca ²⁺ , and Zn ^2+. The golf ball resin composition according to claim 6, which is neutralized with at least one metal ion selected from the group consisting of:   The (a1) binary copolymer constituting the metal ion neutralized product of the binary copolymer, and (a2) the ternary copolymer constituting the metal ion neutralized product of the ternary copolymer, The golf ball resin composition according to claim 6 or 7, wherein the content of the olefin component in the copolymer is 50% by mass or more.   The neutralization degree of the metal ion neutralized product of the (a1) binary copolymer and the metal ion neutralized product of the (a2) ternary copolymer is 50% to 100%. The resin composition for golf balls according to any one of the above.   The golf ball resin composition comprises (C) an amphoteric surfactant and / or (D) a fatty acid in addition to (A) the olefinic ionomer resin and (B) the modified nanocellulose. Item 10. The golf ball resin composition according to any one of Items 1 to 9.   The (C) amphoteric surfactant is a betaine type amphoteric surfactant, an amide amino acid type amphoteric surfactant, an alkylamino fatty acid salt type amphoteric surfactant, an alkylamine oxide type amphoteric surfactant, a β-alanine type amphoteric interface. The resin composition for a golf ball according to claim 10, which is at least one selected from the group consisting of an active agent, a glycine-type amphoteric surfactant, a sulfobetaine-type amphoteric surfactant, and a phosphobetaine-type amphoteric surfactant. object.   The (D) fatty acid is selected from the group consisting of heptanoic acid, octanoic acid, dodecanoic acid, pentadecanoic acid, hexadecanoic acid, octadecanoic acid, icosanoic acid, docosanoic acid, octacosanoic acid, octadecenoic acid, octadecadienoic acid, and icosanoic acid. The resin composition for a golf ball according to claim 10 or 11, which is at least one selected.   A golf ball comprising a constituent member formed from the resin composition for a golf ball according to claim 1. The component member has a slab hardness (H) of 40 to 75 in Shore D hardness,
Flexural rigidity (R) is ^{500kgf / cm 2 ~20,000kgf / cm 2} ,
The golf ball according to claim 13, wherein a ratio (H / R) of the slab hardness (H) and the bending rigidity (R) is 0.002 to 0.100.   The golf ball according to claim 13 or 14, wherein the component member has a polyethylene chain lamellar crystal having a maximum length of 11 nm or more in at least a part of an outer peripheral edge of (B) the modified nanocellulose.