Vitrimer composition, preparation method therefor, and golf ball using same

Abstract

The present invention provides a vitrimer composition based on a thermoplastic polyurethane elastomer, a preparation method therefor, and a golf ball using same. The vitrimer composition according to the present invention has excellent flowability by being partially cross-linked by dynamic covalent bonds, thereby having excellent thin film injection moldability, has a low hardness, and has excellent physical properties of cutting resistance and high rebound resilience. Therefore, the vitrimer composition according to the present invention can be advantageously used for manufacturing a high-performance a golf ball cover layer of three pieces or more.

Description

Vitrimmer composition, method for producing the same, and golf ball using the same

[0001] The present invention relates to a vitrimer composition, a method for producing the same, and a golf ball using the same, and more particularly, to a vitrimer composition having excellent flowability, crosslinking capability simultaneously with injection molding, thus exhibiting excellent thin-film injection moldability, as well as having low hardness, excellent cut resistance, and high rebound elasticity, a method for producing the same, and a golf ball using the same.

[0002] Generally, a high-performance golf ball should offer excellent distance, excellent spin rate, and excellent ball control when hitting iron shots. Typically, golf ball manufacturers use ionomer resin or thermoset polyurethane as the composition of the golf ball cover layer.

[0003] The above ionomer resin is most commonly used as a golf ball cover layer composition due to its excellent durability. However, the ionomer resin is generally too hard, with a hardness of 60D or higher, resulting in poor spin performance, which limits the production of golf balls with excellent performance.

[0004] Accordingly, thermoset polyurethane resin has recently been used in golf ball cover layer compositions to replace ionomer resins and improve cut resistance, rebound resilience, distance, and ball control.

[0005] Thermosetting polyurethane resin, which is commonly used as the outer cover layer material of golf balls, can be manufactured by a cast molding method in which a two-component form consisting of a free polymer and a hardener is injected into a mold and polymerized. During this manufacturing process, the degree of cross-linking can be controlled, thereby improving cutting resistance and rebound elasticity.

[0006] However, when the polymerization process is performed in a two-component form like this, the subject and the curing agent are separated into separate solutions and mixed in the polymerization reaction, which makes the work difficult and makes it difficult to control the curing speed.

[0007] In addition, since the existing ionomer injection molding process equipment for manufacturing the mantle layer and cover layer of golf balls cannot be used, separate casting molding process equipment is required. However, such casting molding process equipment requires a large initial investment, and the burden of equipment investment costs and expensive raw material costs is high.

[0008] Therefore, there is a need for a composition for a golf ball cover layer that can be injection-molded and has cost competitiveness in terms of economic feasibility as well as excellent distance, spin control, cutting resistance and rebound characteristics.

[0009] U.S. Patent Publication No. 2003-0064831 discloses a composition comprising a thermoplastic polyurethane elastomer resin and an isocyanate mixture in which an isocyanate compound having at least two isocyanate groups is dispersed in a thermoplastic polyetherester block copolymer resin that does not substantially react with the isocyanate groups, and which is recyclable during injection molding of a golf ball cover layer and has excellent scuff resistance and rebound resilience.

[0010] However, when these thermoplastic polyurethane elastomer materials are applied to golf ball cover layers of three or more, injection flowability deteriorates, resulting in a cover layer thickness typically exceeding 1.2 mm. This reduces the coefficient of restitution (COR) compared to conventional injection-molded ionomer or cast urethane materials, resulting in reduced distance.

[0011] One object of the present invention is to provide a vitrimer composition having excellent flowability and crosslinking capability simultaneously with injection molding, thereby exhibiting excellent thin-film injection moldability, as well as having low hardness and excellent physical properties such as cut resistance and high rebound elasticity.

[0012] Another object of the present invention is to provide a method for producing the above-mentioned vitriol composition.

[0013] Another object of the present invention is to provide a golf ball formed from the above-described bitrimer composition.

[0014] The present invention's vitriol composition for achieving the above purpose is

[0015] A first pre-vitrimer formed by transesterification of a first thermoplastic polyurethane elastomer having a Shore D hardness of 30 to 40 and a multifunctional compound having two or more alcohol groups under a zinc (Zn)-based catalyst,

[0016] A second pre-vitrimer formed by transesterification of a second thermoplastic polyurethane elastomer having a Shore D hardness of 45 to 60 and a multifunctional compound having two or more alcohol groups under a zinc (Zn)-based catalyst,

[0017] and a multifunctional compound masterbatch having two or more isocyanate groups.

[0018] Meanwhile, the method for manufacturing a vitriol composition according to the present invention

[0019] (i) a step of obtaining a first pre-vitrimer by subjecting a first thermoplastic polyurethane elastomer having a Shore D hardness of 30 to 40 and a multifunctional compound having two or more alcohol groups to an ester exchange reaction under a zinc (Zn)-based catalyst;

[0020] (ii) a step of obtaining a second pre-vitrimer by subjecting a second thermoplastic polyurethane elastomer having a Shore D hardness of 45 to 60 to a transesterification reaction of a multifunctional compound having two or more alcohol groups under a zinc (Zn)-based catalyst; and

[0021] (iii) a step of partially cross-linking the mixture of the first pre-vitrimer and the second pre-vitrimer obtained in the above steps (i) and (ii) with a multifunctional compound masterbatch having two or more isocyanate groups.

[0022] In addition, the golf ball according to the present invention,

[0023] A golf ball comprising a core, a cover layer, and at least one mantle layer present between the core and the cover layer, wherein the cover layer is formed of the vitriol composition.

[0024] The vitrimer composition according to the present invention is partially crosslinked by dynamic covalent bonding, thereby exhibiting excellent flowability and crosslinking simultaneously with injection molding, thereby exhibiting excellent thin-film injection moldability. In addition, the vitrimer composition according to the present invention possesses excellent physical properties such as low hardness, cut resistance, and high resilience. Therefore, the vitrimer composition according to the present invention can be advantageously used in the production of high-performance three-piece or more golf ball cover layers.

[0025] Figure 1 is a cross-sectional view of a golf ball according to one embodiment of the present invention.

[0026] Figure 2 is an FT-IR spectrum of the pre-vitrimer of Manufacturing Example 1.

[0027] Figure 3 is a DSC thermogram of the pre-vitrimer of Manufacturing Example 1.

[0028] Figure 4 is an FT-IR spectrum of the pre-vitrimer of Manufacturing Example 3.

[0029] Figure 5 is a DSC thermogram of the pre-vitrimer of Manufacturing Example 3.

[0030] Hereinafter, the present invention will be described in more detail.

[0031] One embodiment of the present invention

[0032] A first pre-vitrimer formed by transesterification of a first thermoplastic polyurethane elastomer having a Shore D hardness of 30 to 40 and a multifunctional compound having two or more alcohol groups under a zinc (Zn)-based catalyst,

[0033] A second pre-vitrimer formed by transesterification of a second thermoplastic polyurethane elastomer having a Shore D hardness of 45 to 60 and a multifunctional compound having two or more alcohol groups under a zinc (Zn)-based catalyst, and

[0034] A vitriol composition comprising a multifunctional compound masterbatch having two or more isocyanate groups is disclosed.

[0035] According to one embodiment of the present invention, the bitrimer composition may be a mixture of the first pre-bitrimer and the second pre-bitrimer partially cross-linked by a multifunctional compound having two or more isocyanate groups.

[0036] Specifically, the bitrimer composition according to one embodiment of the present invention may be one in which the urethane group and hydroxyl group of the first pre-bitrimer and the second pre-bitrimer are partially cross-linked by a condensation reaction with the isocyanate group of the multifunctional compound having two or more isocyanate groups.

[0037] A vitriol composition according to one embodiment of the present invention has vitriol properties due to dynamic covalent bonding in which bonding and exchange reactions occur between the functional groups.

[0038] A vitrimer is a polymer that is crosslinked by controllable dynamic bonds between polymer chains.

[0039] The bitrimer composition according to one embodiment of the present invention is partially crosslinked by dynamic covalent bonding through a transcarbamoylation reaction or a urethane exchange reaction, and thus has excellent flowability and melt processability to a level where thin film injection molding is possible, and has excellent physical properties such as low compression ratio and high rebound, and excellent cut resistance.

[0040] Specifically, a vitrimer composition according to one embodiment of the present invention comprises a polymer mixture in which a first pre-vitrimer and a second pre-vitrimer mixture, each of which has a different hardness, is subjected to a transesterification reaction in the presence of a multifunctional compound having two or more alcohol groups and a Zn catalyst to reduce the chain length, and is partially crosslinked by a dynamic covalent bond by a multifunctional compound having two or more isocyanate groups. At this time, the urethane group present in the chain of the first pre-vitrimer and the hydroxyl group present at the terminal is crosslinked by a condensation reaction with an isocyanate group of the multifunctional compound having two or more isocyanate groups, and is partially crosslinked to a level that maintains thermoplasticity by a transcarbamoylation reaction or a urethane transesterification reaction occurring within the polymer or between the polymers, thereby forming a network structure.

[0041] In addition, the bitrimer composition according to one embodiment of the present invention is capable of a partial cross-linking reaction during the injection process by using a multifunctional compound having two or more isocyanate groups in the form of a masterbatch.

[0042] Accordingly, the bitrimer composition according to one embodiment of the present invention has high fluidity and can be crosslinked simultaneously with injection molding, thereby ensuring excellent injection moldability that enables forming of a thin film of 0.9 mm or less, for example, between 0.7 mm and 0.9 mm, while having excellent physical properties such as low hardness, low compression ratio, and high resilience.

[0043] In addition, the bitrimer composition according to one embodiment of the present invention can provide a golf ball cover layer having excellent cutting resistance, ball spin, flight distance, distance, and ball hitting feel.

[0044] 1st pre-vitrimer (A)

[0045] In one embodiment of the present invention, the first pre-vitrimmer (A) is a polymer mixture formed by a first thermoplastic polyurethane elastomer having a low hardness of 30 to 40 Shore D hardness and a multifunctional compound containing two or more alcohol groups undergoing an ester exchange reaction under a zinc (Zn)-based catalyst.

[0046] The chain length of the first thermoplastic polyurethane elastomer is reduced by the above ester exchange reaction.

[0047] In one embodiment of the present invention, the first thermoplastic polyurethane elastomer is a thermoplastic block copolymer having a hard segment and a soft segment as a polymerization product of a polyol, a diisocyanate, and a chain extender. The hard segment and the soft segment may be randomly arranged.

[0048] The hard segment is derived by reacting a diisocyanate and a chain extender, and the soft segment is derived by reacting a polyol and a diisocyanate. The properties of the soft segment are determined by the type of polyol used.

[0049] The above polyol may be at least one selected from polyether polyol, polyester polyol and polycarbonate polyol, and in particular may be at least one selected from polyether polyol and polyester polyol.

[0050] The above polyether polyol may be an addition polymerization product of a cyclic ether such as ethylene oxide, propylene oxide, butylene oxide, or tetrahydrofuran. Specifically, the polyether polyol may be polyethylene glycol (PEG), polypropylene glycol (PPG), or polytetramethylene glycol (PTMG).

[0051] The above polyester polyols include polyester polyols obtained by a dehydration condensation reaction of a dicarboxylic acid or an acid ester or an acid anhydride thereof with a diol; polylactone diols obtained by ring-opening polymerization of a lactone monomer such as ε-caprolactone; and the like. At this time, the dicarboxylic acids include aliphatic dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, and azelaic acid; aromatic dicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid, and naphthalenedicarboxylic acid; Examples of alicyclic dicarboxylic acids include hexahydrophthalic acid, hexahydroterephthalic acid, and hexahydroisophthalic acid, and examples of the diols include ethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, 1,3-octanediol, and 1,9-nonanediol.

[0052] The above polycarbonate polyol may be a polycarbonate polyol obtained by reacting one or more types of polyhydric alcohols such as ethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, 1,8-octanediol, 1,9-nonanediol, and diethylene glycol with diethylene carbonate, dimethyl carbonate, diethyl carbonate, or the like.

[0053] The above diisocyanate may be at least one selected from aromatic diisocyanate, aliphatic diisocyanate, and alicyclic diisocyanate.

[0054] Examples of the above aromatic diisocyanates include 1,4-phenylene diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 2,2-methylenediphenylene diisocyanate, 2,4'-methylenediphenylene diisocyanate, 4,4'-methylenediphenylene diisocyanate, naphthalene diisocyanate, xylene diisocyanate (XDI), tetramethylxylene diisocyanate (TMXDI), etc.

[0055] Examples of the above aliphatic diisocyanates include hexamethylene diisocyanate, 1,8-diisocyanatemethyloctane, etc.

[0056] Examples of the above alicyclic diisocyanates include 1,4-cyclohexane diisocyanate, 1-methyl-2,4-cyclohexane diisocyanate, 1-methyl-2,6-cyclohexane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 2,4'-dicyclohexylmethane diisocyanate, 2,2'-dicyclohexylmethane diisocyanate, and isophorone diisocyanate (IPDI).

[0057] As the chain extender, a low molecular weight polyol or diamine is used. For example, the chain extender includes aliphatic polyols such as ethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, 1,8-octanediol, 1,9-nonanediol, diethylene glycol, 1,4-cyclohexanedimethanol, glycerin, etc.; aromatic polyols such as 1,4-dimethylolbenzene, bisphenol A, ethylene oxide or propylene oxide adducts of bisphenol A, etc. Examples include diamine compounds such as isophoronediamine, ethylenediamine, 1,2-propylenediamine, 1,3-propylenediamine, N-methylpropylene-1,3-diamine, and N,N'-dimethylethylenediamine.

[0058] In one embodiment of the present invention, the content ratio of the hard segment and the soft segment constituting the first thermoplastic polyurethane elastomer may be 90:10 to 10:90 by weight, and in particular, in order to facilitate polymerization and sufficiently exhibit properties as an elastic material, it may be preferably 85:15 to 15:85, more preferably 80:20 to 20:80, still more preferably 75:25 to 25:75, and still more preferably 70:30 to 30:70.

[0059] In one embodiment of the present invention, the first thermoplastic polyurethane elastomer has a low hardness characteristic of Shore D hardness of 30 to 40. The Shore D hardness can be adjusted by controlling the type of monomer constituting the first thermoplastic polyurethane elastomer, or the content ratio of the hard segment and the soft segment.

[0060] The above Shore D hardness is measured according to ASTM D2240.

[0061] When the Shore D hardness of the first thermoplastic polyurethane elastomer is within the above range, durability and injection moldability can be improved.

[0062] In one embodiment of the present invention, the first thermoplastic polyurethane elastomer may have a melt index of 5 to 30 g / 10 min as measured at 210°C and 5 kg according to ASTM D1238.

[0063] In one embodiment of the present invention, the first thermoplastic polyurethane elastomer may have a number average molecular weight (Mn) of 5,000 to 500,000 g / mol, for example, 10,000 to 300,000, 10,000 to 250,000, 10,000 to 230,000, 10,000 to 220,000, 10,000 to 210,000, 10,000 to 200,000, 10,000 to 190,000, 10,000 to 180,000, 11,000 to 180,000, or 11,000 to 150,000 g / mol. If the number average molecular weight is less than 5,000 g / mol, the mechanical properties such as tensile strength and toughness of the product obtained from the composition may be poor, and if it exceeds 500,000 g / mol, the melt processability of the composition may be poor.

[0064] In one embodiment of the present invention, the polyfunctional compound having two or more alcohol groups forming the first pre-vitrimer means a compound having two or more alcohol groups in a molecule, i.e., a polyhydric alcohol.

[0065] Examples of the polyfunctional compounds having two or more alcohol groups include glycerin, 1,2-ethanediol, pentaerythritol, etc., and glycerin is particularly preferred. These may be used alone or in combination of two or more.

[0066] The polyfunctional compound having two or more alcohol groups may be used in an amount of 0.05 to 2 parts by weight, for example, 0.1 to 1.0 parts by weight, based on 100 parts by weight of the first thermoplastic polyurethane elastomer. If the polyfunctional compound having two or more alcohol groups is used in an amount below the above range, the transesterification reaction may not occur, and if it is used in an amount exceeding the above range, the transesterification reaction may occur too much, resulting in a decrease in elongation.

[0067] In one embodiment of the present invention, the zinc (Zn)-based catalyst forming the first pre-vitrimer can be used without limitation as long as it is used in an ester exchange reaction, and examples thereof include zinc acetylacetonate, zinc acetate, etc. These may be used alone or in combination of two or more.

[0068] The above zinc (Zn)-based catalyst can be used in an amount of 0.01 to 0.5 parts by weight per 100 parts by weight of the first thermoplastic polyurethane elastomer. When the zinc (Zn)-based catalyst is used in the above range, the ester exchange reaction can occur efficiently.

[0069] The above zinc (Zn)-based catalyst is suitably used in an amount of 1 / 10 to 2 / 10 of the content of the polyfunctional compound having two or more alcohol groups.

[0070] In one embodiment of the present invention, the first pre-vitrimmer (A) may have a melt index of 50 to 300 g / 10 min, measured at 210°C and 5 kg according to ASTM D1238. When the first pre-vitrimmer (A) has a melt index within the above range, it has many crosslinking points and thus has excellent elasticity during crosslinking.

[0071] In one embodiment of the present invention, the first pre-vitrimmer (A) may have an elongation at break of 300% or more, for example, 300 to 500%. If the elongation is less than 300%, low-temperature durability may be reduced.

[0072]

[0073] Second pre-vitrimer (B)

[0074] In one embodiment of the present invention, the second pre-vitrimer (B) is a polymer mixture formed by a high-hardness second thermoplastic polyurethane elastomer and a multifunctional compound having two or more alcohol groups undergoing an ester exchange reaction under a zinc (Zn)-based catalyst.

[0075] The chain length of the second thermoplastic polyurethane elastomer is reduced by the above ester exchange reaction.

[0076] In one embodiment of the present invention, the second thermoplastic polyurethane elastomer is a thermoplastic block copolymer having a hard segment and a soft segment as a polymerization product of a polyol, a diisocyanate, and a chain extender. The hard segment and the soft segment may be randomly arranged.

[0077] The hard segment and soft segment constituting the second thermoplastic polyurethane elastomer may be identical to the hard segment and soft segment constituting the first thermoplastic polyurethane elastomer. Accordingly, a detailed description thereof is omitted.

[0078] In one embodiment of the present invention, the content ratio of the hard segment and the soft segment constituting the second thermoplastic polyurethane elastomer may be 90:10 to 10:90 by weight, and in particular, in order to facilitate polymerization and sufficiently exhibit properties as an elastic material, it may be preferably 85:15 to 15:85, more preferably 80:20 to 20:80, still more preferably 75:25 to 25:75, and still more preferably 70:30 to 30:70.

[0079] In one embodiment of the present invention, the second thermoplastic polyurethane elastomer has a Shore D hardness higher than that of the first thermoplastic polyurethane elastomer. Preferably, the second thermoplastic polyurethane elastomer may have a Shore D hardness of 45 to 60. The Shore D hardness can be adjusted by controlling the type of monomer constituting the second thermoplastic polyurethane elastomer, or the content ratio of the hard segment and the soft segment.

[0080] The above Shore D hardness is measured according to ASTM D2240.

[0081] When the Shore D hardness of the second thermoplastic polyurethane elastomer is within the above range, the cut resistance can be improved.

[0082] In one embodiment of the present invention, the second thermoplastic polyurethane elastomer may have a melt index of 5 to 30 g / 10 min as measured at 210°C and 5 kg according to ASTM D1238.

[0083] In one embodiment of the present invention, the second thermoplastic polyurethane elastomer may have a number average molecular weight (Mn) of 5,000 to 500,000 g / mol, for example, 10,000 to 300,000, 10,000 to 250,000, 10,000 to 230,000, 10,000 to 220,000, 10,000 to 210,000, 10,000 to 200,000, 10,000 to 190,000, 10,000 to 180,000, 11,000 to 180,000, or 11,000 to 150,000 g / mol. If the number average molecular weight is less than 5,000 g / mol, the mechanical properties such as tensile strength and toughness of the product obtained from the composition may be poor, and if it exceeds 500,000 g / mol, the melt processability of the composition may be poor.

[0084] In one embodiment of the present invention, the multifunctional compound having two or more alcohol groups forming the second pre-bitumen and the zinc (Zn)-based catalyst may be the same as the multifunctional compound having two or more alcohol groups forming the first pre-bitumen and the zinc (Zn)-based catalyst described above, and the amount used may be in the same range. Accordingly, a detailed description thereof is omitted.

[0085] In one embodiment of the present invention, the second pre-vitrimmer (B) may have a melting index of 50 to 300 g / 10 min, measured at 210°C and 5 kg according to ASTM D1238. When the second pre-vitrimmer (B) has a melting index within the above range, it has many crosslinking points and thus has excellent elasticity during crosslinking.

[0086] In one embodiment of the present invention, the second pre-vitrimmer (B) may have an elongation at break of 300% or more, for example, 300 to 500%. If the elongation is less than 300%, low-temperature durability may be reduced.

[0087] In one embodiment of the present invention, the mixing ratio of the first pre-vitrimmer (A) and the second pre-vitrimmer (B) may be 10:90 to 50:50, preferably 30:70 to 50:50, by weight. When the mixing ratio of the first pre-vitrimmer (A) and the second pre-vitrimmer (B) is within the above range, cutting resistance may be improved. If the first pre-vitrimmer (A) is used in an amount below the above range, durability may be reduced, and if it is used in an amount exceeding the above range, hardness may be increased, resulting in deterioration of spin control.

[0088]

[0089] Multifunctional compound masterbatch (C) having two or more isocyanate groups

[0090] In one embodiment of the present invention, the multifunctional compound masterbatch (C) having two or more isocyanate groups may be a multifunctional compound having two or more isocyanate groups dispersed in a thermoplastic polymer resin.

[0091] The multifunctional compound masterbatch (C) having two or more isocyanate groups may be in the form of pellets.

[0092] The above thermoplastic polymer resin is a carrier resin of a multifunctional compound having two or more isocyanate groups, and may preferably be a thermoplastic polyester resin.

[0093] The polyfunctional compound having two or more isocyanate groups is a compound having two or more isocyanate groups in the molecule, and examples thereof include naphthalene diisocyanate (NDI), paraphenylene diisocyanate (PPDI), tolidine diisocyanate (TODI), diphenyl methane diisocyanate (MDI), toluene diisocyanate (TDI), hexamethylene diisocyanate (HDI), dicyclohexylmethane diisocyanate (H12MDI), isophorone diisocyanate (IPDI), etc., and diphenyl methane diisocyanate (MDI) is particularly preferred. These can be used alone or in combination of two or more.

[0094] In one embodiment of the present invention, the content of the multifunctional compound having two or more isocyanate groups in the multifunctional compound masterbatch having two or more isocyanate groups may be 10 to 30 wt% with respect to 100 wt% of the total masterbatch. When the content of the multifunctional compound having two or more isocyanate groups in the multifunctional compound masterbatch having two or more isocyanate groups is within the above range, the first pre-vitrimmer and the second pre-vitrimmer can be partially crosslinked by the multifunctional compound having two or more isocyanate groups, thereby maintaining thermoplasticity and enabling cost reduction.

[0095] In one embodiment of the present invention, the thermoplastic polymer resin in the multifunctional compound masterbatch having two or more isocyanate groups may be included as a remainder so as to make up 100 wt% of the entire masterbatch.

[0096] In one embodiment of the present invention, the multifunctional compound masterbatch (C) having two or more isocyanate groups may be included in an amount of 5.0 to 20.0 parts by weight, preferably 7.5 to 12.5 parts by weight, and more preferably 9 to 12 parts by weight, based on 100 parts by weight of the total amount of the first pre-vitrimer and the second pre-vitrimer. When the multifunctional compound masterbatch having two or more isocyanate groups is included in the above content range, the first pre-vitrimer and the second pre-vitrimer may be partially crosslinked by the multifunctional compound having two or more isocyanate groups, thereby maintaining thermoplasticity. When the multifunctional compound masterbatch having two or more isocyanate groups is included in an amount less than the above content range, cut resistance may be reduced, and when it is included in an amount exceeding the above content range, injection processability may be reduced.

[0097]

[0098] Additive (D)

[0099] The bitrimer composition according to one embodiment of the present invention may further include various additives (D) as needed in addition to the above-described components.

[0100] Examples of the above additives (D) include antioxidants, heat stabilizers, light stabilizers, lubricants, reinforcing agents (e.g., silicone resins), hydrolysis inhibitors, ultraviolet absorbers, pigments, dyes, lubricants, anti-blocking agents, etc.

[0101] Examples of the antioxidant include, but are not limited to, hindered amine-based antioxidants, hindered phenol-based antioxidants, phosphite-based antioxidants, amide-based antioxidants, thioester-based antioxidants, or combinations thereof, and more specifically, 4,4'-bis(α,α-diphenylbenzyl) diphenyl amine (Naugard 445 from Chemtura), octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate (Irganox 1076 from BASF).

[0102] The above additives may be used in the form of a masterbatch. For example, a color masterbatch may be used in which pigments and / or dyes are dispersed in a thermoplastic polymer resin as a carrier resin.

[0103] These additives are preferably used in an amount of 0.1 to 4 parts by weight in total, and 0.05 to 1 part by weight for each additive, per 100 parts by weight of the Vitrimer composition.

[0104] The vitriol composition according to one embodiment of the present invention is a highly elastic material having a high coefficient of restitution (COR).

[0105] Specifically, when the vitriol composition according to one embodiment of the present invention is molded into a sphere having a diameter of 1.55 to 1.63 inches, the sphere may have a coefficient of restitution (COR) of 0.799 or more, for example, 0.800 or more, and a compressibility of 105 or less, for example, 103 or less, or 102 or less.

[0106] The above coefficient of restitution (COR) can be determined by firing the ball at a speed of 125 feet per second at a steel plate located 3 feet away from the initial velocity measurement point, and dividing the rebound velocity from the steel plate by the initial velocity.

[0107] The above compression ratio is defined as the total resistance to deflection experienced by a golf ball when a compressive load is applied.

[0108] The above compression ratio can be measured by the method described in the experimental example described below.

[0109] The above ranges of rebound coefficient and compression ratio are desirable in terms of the performance of the golf ball.

[0110] The bitrimer composition according to one embodiment of the present invention may have a Shore D hardness of 45 to 58. The above Shore D hardness range is preferable in terms of performance of the golf ball.

[0111] The bitrimer composition according to one embodiment of the present invention can control the hardness in various ways within the above range, making it easier to control the thickness compared to existing thermoplastic polyurethane elastomer resins, thereby increasing the degree of freedom in designing golf balls of three or more pieces.

[0112] The vitriol composition according to one embodiment of the present invention has excellent flowability to a level where it can be injected into a thin film having a thickness of 0.9 mm or less, for example, between 0.7 mm and 0.9 mm, as described above, and has excellent thin film molding processability, so that it can be advantageously used as a material for a cover layer of three or more golf balls, replacing existing thermoplastic polyurethane elastomer compositions or ionomer resins that can be injected into a thickness of 1.2 mm or more.

[0113]

[0114] One embodiment of the present invention

[0115] (i) a step of obtaining a first pre-vitrimer by subjecting a first thermoplastic polyurethane elastomer having a Shore D hardness of 30 to 40 and a multifunctional compound having two or more alcohol groups to an ester exchange reaction under a zinc (Zn)-based catalyst;

[0116] (ii) a step of obtaining a second pre-vitrimer by subjecting a second thermoplastic polyurethane elastomer having a Shore D hardness of 45 to 60 to a transesterification reaction of a multifunctional compound having two or more alcohol groups under a zinc (Zn)-based catalyst; and

[0117] (iii) A method for producing a vitrimer composition, comprising a step of partially cross-linking a mixture of the first pre-vitrimer and the second pre-vitrimer obtained in the above steps (i) and (ii) with a multifunctional compound masterbatch having two or more isocyanate groups.

[0118]

[0119] The above steps (i) and (ii) are steps for producing a first pre-vitrimer and a second pre-vitrimer by subjecting each of the first thermoplastic polyurethane elastomer and the second thermoplastic polyurethane elastomer to an ester exchange reaction with a multifunctional compound having two or more alcohol groups in the presence of a zinc (Zn)-based catalyst in order to reduce the chain length of the first thermoplastic polyurethane elastomer and the second thermoplastic polyurethane elastomer.

[0120] The first thermoplastic polyurethane elastomer and the second thermoplastic polyurethane elastomer, the multifunctional compound having two or more alcohol groups, the zinc (Zn)-based catalyst, the first pre-vitrimer and the second pre-vitrimer have already been described in the description of the above-described vitrimer composition, and thus a detailed description thereof will be omitted.

[0121] The ester exchange reaction of steps (i) and (ii) above can be performed under melt conditions in an extruder.

[0122] Specifically, the steps (i) and (ii) can be performed by supplying each of the first thermoplastic polyurethane elastomer and the second thermoplastic polyurethane elastomer together with a multifunctional compound having two or more alcohol groups and a zinc (Zn)-based catalyst to a hopper of a twin-screw extruder, and then uniformly mixing and melting the components supplied through the hopper while increasing the barrel temperature of the twin-screw extruder and conveying them to the tip of the barrel to perform an ester exchange reaction.

[0123] In the above steps (i) and (ii), the melting conditions may be temperature conditions of 190 to 230°C.

[0124] The above steps (i) and (ii) may be performed in different order and may be performed simultaneously on different twin-screw extruders.

[0125] In the above steps (i) and (ii), before feeding each component into the hopper of the twin-screw extruder, each component can be sufficiently and homogeneously mixed in advance using a mixer such as a ribbon mixer.

[0126] The above step (iii) is a step of obtaining a vitrimer composition by partially cross-linking a mixture of the first pre-vitrimer and the second pre-vitrimer obtained in the above steps (i) and (ii), respectively, with a multifunctional compound masterbatch having two or more isocyanate groups.

[0127] The partial crosslinking in step (iii) above can be performed under melt conditions in at least one of the injection molding machine and the mold. That is, the partial crosslinking in step (iii) above can be performed under melt conditions in the injection molding machine, and can also occur in the mold for molding. Accordingly, injection molding can be performed simultaneously with the partial crosslinking in step (iii).

[0128] Specifically, the step (iii) may be performed by uniformly mixing a mixture of the first pre-vitrimer and the second pre-vitrimer obtained in each of the steps (i) and (ii) with a multifunctional compound masterbatch having two or more isocyanate groups, supplying the mixture to a hopper of an injection molding machine, melting the mixture in the injection molding machine, and then introducing the mixture into a mold to perform partial cross-linking and molding at the same time.

[0129] The mixture of the first pre-vitrimer and the second pre-vitrimer obtained in each of the above steps (i) and (ii) can be dried in a dehumidifying dryer before being fed into the injection molding machine.

[0130] The above partial cross-linking can be performed within a level where the vitrimer composition maintains thermoplasticity. That is, the above partial cross-linking can be performed by partially cross-linking a mixture of the first pre-vitrimer and the second pre-vitrimer with a multifunctional compound having two or more isocyanate groups within a level where the thermoplasticity is maintained.

[0131] The above-mentioned vitrifier composition can be processed into a cover layer for a golf ball. For example, the golf ball can be a golf ball having three or more pieces.

[0132] Accordingly, one embodiment of the present invention relates to a golf ball having a cover layer formed of the above-described bitrimer composition.

[0133] Referring to FIG. 1, a golf ball according to one embodiment of the present invention includes a core (10), a cover layer (30), and a mantle layer (20) existing between the core (10) and the cover layer (30). Although FIG. 1 illustrates a configuration with one mantle layer, the mantle layer may exist as two or more multiple layers.

[0134] The above core (10) is the innermost layer of the golf ball and may have a single layer or a multi-layer structure of two or more layers.

[0135] Any known core material can be used as the core (10) material, and examples thereof include thermosetting materials such as rubber, styrene butadiene, polybutadiene, isoprene, polyisoprene, and trans-isoprene; thermoplastic materials such as ionomer resins, polyamides, or polyesters; and thermoplastic and thermosetting polyurethane or polyurea elastomers.

[0136] The above mantle layer (20) is an intermediate layer existing between the core (10) and the cover layer (30) of the golf ball, and has a multi-layer structure of a single layer or two or more layers.

[0137] Any known mantle layer material can be used as the material for the above mantle layer (20), and examples thereof include ionomer resin, thermoplastic polyester elastomer, etc. Commercially available products of the above ionomer resin include Dow's Surlyn 8150 and 9150.

[0138] The above mantle layer (20) can be formed using the above-described mantle layer material to cover the core (10).

[0139] The above cover layer (30) is the outermost layer of the golf ball and has a single-layer structure.

[0140] The above cover layer (30) can be formed using the above-described vitriol composition to cover the mantle layer (20).

[0141] Hereinafter, the present invention will be described in more detail through examples, comparative examples, and experimental examples. These examples, comparative examples, and experimental examples are intended solely to illustrate the present invention, and it will be apparent to those skilled in the art that the scope of the present invention is not limited thereto.

[0142]

[0143] Manufacturing example: Manufacturing of pre-vitrimer

[0144] Each component was weighed and mixed according to the composition in Table 1 below and fed into a twin-screw extruder (32 mm, L / D=44; manufacturer: Uniplus, product number: UNEE 32-44) through the hopper of the extruder.

[0145] A pre-vitrimer was manufactured by melt extrusion while maintaining the barrel temperature at approximately 190 to 230°C and the shaft rotation speed of the twin-screw extruder in the range of approximately 200 to 400 rpm.

[0146]

[0147] Experimental Example 1:

[0148] The tensile strength at break, elongation at break, melt index, and hardness of the pre-vitrimers manufactured in the above manufacturing examples were measured by the following methods, and the measurement results are shown in Table 1 below. In addition, FT-IR and DSC analyses of the pre-vitrimers manufactured in Manufacturing Examples 1 and 3 were performed as follows, and the results are shown in Figures 2 to 5, respectively.

[0149]

[0150] (1) Tensile strength at break and elongation at break

[0151] Tensile strength and elongation at break were measured according to ASTM D638.

[0152]

[0153] (2) Melting index

[0154] The melting index was measured under the measurement conditions of 210℃ and 5 kg load according to ASTM D1238.

[0155]

[0156] (3) Hardness

[0157] Hardness was measured as Shore D hardness according to ASTM D2240.

[0158]

[0159] (4) FT-IR

[0160] FT-IR was analyzed using a PerkinElmer Spectrum2 instrument.

[0161]

[0162] (5) DSC analysis

[0163] Differential scanning calorimetry (DSC) analysis was performed using a DSC 4000 Lab system with a heating rate of 10°C / min.

[0164]

[0165] Manufacturing Example 1 Manufacturing Example 2 Manufacturing Example 3 Manufacturing Example 4 Manufacturing Example 5 Manufacturing Example 6 Composition (weight parts) Elastollan 1185A M 100 100 Elastollan 1154D 100 100 Elastollan 1195A 100 100 Glycerin 0.25 0.5 0.25 0.5 0.25 0.5 Zn-based catalyst 0.10 10.10 10.10 10.1 Physical properties Tensile strength at break (MPa) 30.5 30.1 49.2 49.7 42.7 42.1 Elongation at break (%) > 300 > 300 > 300 > 300 > 300 > 300 Melt index (g / 10 min) 180 224 155 172 171 205 Hardness (Shore D) 39 39 535 348 48

[0166]

[0167] Elastollan 1185A M (BASF): polyether-based thermoplastic polyurethane elastomer (Shore A hardness 88, Shore D hardness: 39)

[0168] Elastollan 1154D (BASF): Polyether-based thermoplastic polyurethane elastomer (Shore D hardness: 53)

[0169] Elastollan 1195A (BASF): polyether-based thermoplastic polyurethane elastomer (Shore A hardness: 96, Shore D hardness: 48)

[0170] Zn-based catalyst: zinc acetylacetonate

[0171] Through the above Table 1, it can be seen that the pre-vitrimers of Manufacturing Examples 1 to 6 are within the appropriate melting index range.

[0172] Figures 2 to 5 are FT-IR spectra and DSC thermograms of the pre-vitrimers of Manufacturing Examples 1 and 3, respectively.

[0173] Through Figures 2 to 5, it can be seen that the thermoplastic polyurethane elastomer has undergone an ester exchange reaction.

[0174]

[0175] Examples and Comparative Examples:

[0176] Each component was weighed according to the composition in Table 2 below, and the MDI masterbatch and color masterbatch were mixed and injected into the injection molding machine (Woojin Plaim Co., Ltd., VH-RG5) through the hopper of the injection molding machine. The MDI masterbatch used was a thermoplastic polyester carrier resin containing 30 wt% diphenyl methane diisocyanate (MDI). The color masterbatch used was SMP MB (TPU base, Sammi).

[0177] While maintaining the temperature inside the injection molding machine at approximately 190 to 240°C, the molten material was injected into a mold and injection-molded into spheres as shown below. Various physical properties required for golf balls were measured. The results are shown in Tables 2 to 5 below. Each measurement value is the average of 20 measurements.

[0178] Spherical Plastic Surgery

[0179] Each composition having the composition shown in Table 2 below was injection-molded into a spherical specimen the size of a golf ball with a diameter of 1.59 inches to form a cover layer. At this time, the thickness of the cover layer was 0.7 mm. In addition, the core used was a 40.5 mm diameter polybutadiene rubber material, and the mantle layer used Surlyn 8150 / Surlyn 9150 (Dow) as a material.

[0180]

[0181] (1) Hardness

[0182] Hardness was measured using a Shore D hardness tester manufactured by MiSUMi, Japan, according to the German standard DIN 53505. A higher number indicates higher hardness and a harder surface.

[0183]

[0184] (2) Coefficient of Restitution (COR)

[0185] The coefficient of restitution was measured using a ball and core COR / Durability tester manufactured by Automated Design Company (ADC) in the United States. Specifically, the coefficient of restitution was determined by launching the ball at a speed of 125 feet per second against a steel plate located 3 feet away from the initial velocity measurement point, and dividing the rebound velocity from the steel plate by the initial velocity.

[0186] The higher the coefficient of restitution, the better the elasticity and durability.

[0187]

[0188] (3) Compression ratio

[0189] Compression was measured using a golf ball compression tester from Atti, USA.

[0190] The higher the compression ratio, the harder the ball is.

[0191]

[0192] (4) Ball Spin Rate

[0193] Ball spin was measured using a robot swing tester (product name: MIYAROBO-3) manufactured by Miyamae, Japan. Specifically, ball spin was calculated by measuring the rotational speed of a golf ball when hitting it with a driver (a golf club with a loft angle of 9.5 degrees) at a club head speed of 45 m / sec, and converting this to rotations per minute (RPM).

[0194]

[0195] (5) Flight Distance

[0196] Flight distance was measured using a robot swing tester (product name: MIYAROBO-3) manufactured by Miyamae, Japan. Specifically, flight distance was determined by measuring the flight distance of the ball when hitting under conditions equivalent to ball spin.

[0197] The higher the number, the better the flight distance performance.

[0198]

[0199] (6) Total Distance

[0200] The total distance was calculated by adding up the flight distance and rolling distance of the ball through a hitting test under the same conditions as the flight distance.

[0201] The higher the number, the better the distance performance.

[0202]

[0203] (7) Ball hitting feel

[0204] Ten average golfers (handicap 10 or lower) played a round on a golf course and evaluated the feel of the shot. Each participant gave their score out of 10, calculating the average score and reporting it according to the evaluation criteria below.

[0205] <Evaluation Criteria>

[0206] ◎: 8 points or more

[0207] ○: 6 points or more but less than 8 points

[0208] △: 4 points or more but less than 6 points

[0209] ×: Less than 4 points

[0210]

[0211] (8) Cutting resistance

[0212] Using a golf club PW (Pitching Wedge), the same area of ​​the golf ball was repeatedly struck 6 times at a club head speed of 35 m / sec, and the cutting performance of the golf ball cover was evaluated according to the following evaluation criteria.

[0213] <Evaluation Criteria>

[0214] ◎: Very good

[0215] ○: Good

[0216] △: Normal

[0217] ×: Defective

[0218]

[0219] (9) Injection processability

[0220] Injection processability was evaluated according to the following evaluation criteria.

[0221] <Evaluation Criteria>

[0222] ◎: 8 out of 8 holes can be molded

[0223] ○: 1~2 out of 8 are missing

[0224] △: 3~4 out of 8 are missing

[0225] ×: 5 or more out of 8 are missing

[0226]

[0227]

[0228] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Manufacturing Example 1 50 30 30 Manufacturing Example 2 50 30 30 Manufacturing Example 3 50 70 Manufacturing Example 4 50 70 Manufacturing Example 570 Manufacturing Example 6 70 MDI Masterbatch 7.5 7.5 7.5 7.5 7.5 7.5 Color Masterbatch 5 5 5 5 5 Hardness 5 3 5 6 5 3 5 6 5 2 5 2 COR 0.8 0 2 0.8 0 4 0.8 0 3 0.8 0 5 0.8 0 1 0.8 1 Compression Ratio 9 8 1 0 0 9 8 1 0 0 9 6 9 6 Ball Spin Power (rpm) 3,86 2 3,83 7 3,85 6 3,82 3 3,91 4 3,92 0 Flight Distance (m) 2 30.6 2 3 1.2 2 3 0.8 2 3 1.8 2 2 9 1 2 9 5 Total Distance (m) 250.4251.2250.4251.9249.3249.7 Ball hitting feel ○◎○◎◎◎ Cutting resistance ○○○○○○ Injection processability (0.7 mm) ◎◎◎◎◎◎

[0229]

[0230] Example 7 Example 8 Example 9 Example 10 Example 11 Example 12 Manufacturing Example 1503030 Manufacturing Example 2503030 Manufacturing Example 35070 Manufacturing Example 45070 Manufacturing Example 570 Manufacturing Example 670 MDI Masterbatch 101010101010 Color Masterbatch 555555 Hardness 545754575353 COR 0.80 30.80 50.80 40.80 60.80 20.80 2 Compression Ratio 99101991019798 Ball Spin Power (rpm) 3,8653,8323,8513,8263,9103,917 Flight Distance (m) 230.9231.5231.1232.3229.5229.8 Total Distance (m) 250.5 251.6 250.7 252.4 249.8 250.1 Ball hitting feel ○◎○◎◎◎ Cutting resistance ◎◎◎◎◎◎ Injection processability (0.7 mm) ◎◎◎◎◎

[0231]

[0232]

[0233] Example 13 Example 14 Example 15 Example 16 Example 17 Example 18 Manufacturing Example 1503030 Manufacturing Example 2503030 Manufacturing Example 35070 Manufacturing Example 45070 Manufacturing Example 570 Manufacturing Example 670 MDI Masterbatch 12.5 12.5 12.5 12.5 12.5 12.5 Color Masterbatch 5 5 5 5 5 Hardness 5 5 5 5 5 5 3 5 3 COR 0.80 4 0.80 5 0.80 5 0.80 6 0.80 2 0.80 3 Compression Ratio 10 0 10 2 10 0 10 2 10 0 10 0 Ball Spin power (rpm) 3,86 13,82 83,84 63,82 13,92 33,93 1 Flight distance (m) 231.1 231.8 231.6 232.8 229.0 230.3 Total distance (m) 250.6 251.9 250.8 252.7 249.1 249.8 Ball hitting feel ○◎○◎○○ Cutting resistance ◎◎◎◎◎◎ Injection processability (0.7 mm) ○○◎◎○◎

[0234]

[0235] Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Elastollan 1185A M50305030 Elastollan 1154D50705070 MDI Masterbatch 7.57.51010 Color Masterbatch 5555 Hardness 5255--COR 0.8000.801--Compression Ratio 9698--Ball Spin Power (rpm) 3,8733,845--Flight Distance (m) 229.6229.2--Total Distance (m) 249.1250.6--Ball Hit Feel ○◎--Cutting Resistance △△--Injection Processability (0.7mm) ○○××

[0236]

[0237] As shown in Tables 2 to 4 above, it was confirmed that the vitrimer compositions of Examples 1 to 18 according to the present invention had excellent flowability and thin film moldability to the extent that they could be injected into a thin film of 0.7 mm or less, and also had excellent cut resistance. At this time, it was found that when the content of the MDI masterbatch decreased, the cut resistance decreased, and when the content of the MDI masterbatch increased, the injection moldability decreased. However, it was confirmed that the vitrimer compositions of Examples 15, 16, and 18, in which the melt index (MI) of the first and second pre-vitrimers was high, had excellent flowability and thin film injection moldability even when the content of the MDI masterbatch increased.

[0238] On the other hand, as shown in Table 5 above, the crosslinked thermoplastic polyurethane elastomer compositions of Comparative Examples 1 to 4 that do not use a pre-vitrimer were found to be unable to simultaneously secure cut resistance and thin-film injection moldability. Specifically, the crosslinked thermoplastic polyurethane elastomer compositions of Comparative Examples 1 and 2 that did not use a pre-vitrimer and had a low content of MDI masterbatch showed some non-forming and were capable of thin-film injection molding with a thickness of 0.7 mm or less, but had poor cut resistance, and the crosslinked thermoplastic polyurethane elastomer compositions of Comparative Examples 3 and 4 that did not use a pre-vitrimer and had an increased content of MDI masterbatch were found to have poor melt processability and were unable to be injection molded with a thickness of 0.7 mm.

[0239] In addition, it can be seen that the spheres formed from the vitriol compositions of Examples 1 to 18 according to the present invention have a coefficient of restitution (COR) of 0.800 or more and a compression ratio of 105 or less. This shows similar compression ratios and good coefficient of restitution values ​​compared to the spheres formed from the crosslinked thermoplastic polyurethane elastomer compositions of Comparative Examples 1 and 2, which were previously used in golf ball cover layers.

[0240] Therefore, it can be confirmed that the vitriol composition according to the present invention can be used as a substitute material for existing thermoplastic polyurethane elastomer compositions or ionomer resins for three or more golf ball cover layers.

[0241] While specific aspects of the present invention have been described in detail above, it should be apparent to those skilled in the art that these specific descriptions are merely preferred embodiments and do not limit the scope of the present invention. Those skilled in the art will be able to make various applications and modifications within the scope of the present invention based on the above description.

[0242] Accordingly, the substantial scope of the present invention will be defined by the appended claims and their equivalents.

Claims

1. A first pre-vitrimer formed by transesterification of a first thermoplastic polyurethane elastomer having a Shore D hardness of 30 to 40 and a multifunctional compound having two or more alcohol groups under a zinc (Zn)-based catalyst. A second pre-vitrimer formed by transesterification of a second thermoplastic polyurethane elastomer having a Shore D hardness of 45 to 60 and a multifunctional compound having two or more alcohol groups under a zinc (Zn)-based catalyst, and A vitriol composition comprising a multifunctional compound masterbatch having two or more isocyanate groups.

2. A vitrimer composition in accordance with claim 1, wherein the mixture of the first pre-vitrimer and the second pre-vitrimer is partially cross-linked by a multifunctional compound having two or more isocyanate groups.

3. A vitrimer composition in accordance with claim 1, wherein the urethane group and hydroxyl group of the first pre-vitrimer and the second pre-vitrimer are partially cross-linked by a condensation reaction with an isocyanate group of a multifunctional compound having two or more isocyanate groups.

4. A vitrimer composition in the first paragraph, wherein the multifunctional compound having two or more alcohol groups is at least one selected from the group consisting of glycerin, 1,2-ethanediol, and pentaerythritol.

5. A vitrimer composition in which the multifunctional compound having two or more alcohol groups in the first paragraph is used in an amount of 0.05 to 2 parts by weight per 100 parts by weight of the first thermoplastic polyurethane elastomer or the second thermoplastic polyurethane elastomer, respectively.

6. A vitriol composition in the first paragraph, wherein the zinc (Zn)-based catalyst is at least one of zinc acetylacetonate and zinc acetate.

7. In the first paragraph, the first pre-vitrimer and the second pre-vitrimer are a vitrimer composition having a melting index of 50 to 300 g / 10 min as measured at 210°C and 5 kg according to ASTMD1238.

8. A vitrimer composition in the first paragraph, wherein the mixing ratio of the first pre-vitrimer and the second pre-vitrimer is 10:90 to 50:50 by weight.

9. In the first paragraph, the multifunctional compound masterbatch having two or more isocyanate groups is a vitriol composition in which a multifunctional compound having two or more isocyanate groups is dispersed in a thermoplastic polymer resin.

10. A vitrimer composition according to claim 9, wherein the thermoplastic polymer resin is a thermoplastic polyester resin.

11. In the first paragraph, the multifunctional compound having two or more isocyanate groups is at least one selected from the group consisting of naphthalene diisocyanate (NDI), paraphenylene diisocyanate (PPDI), tolidine diisocyanate (TODI), diphenyl methanediisocyanate (MDI), toluene diisocyanate (TDI), hexamethylene diisocyanate (HDI), dicyclohexylmethane diisocyanate (H12MDI), and isophorone diisocyanate (IPDI).

12. A vitriol composition in accordance with claim 1, wherein the content of the multifunctional compound having two or more isocyanate groups in the multifunctional compound masterbatch having two or more isocyanate groups is 10 to 30 wt% with respect to 100 wt% of the total masterbatch.

13. A vitrimer composition according to claim 1, wherein the multifunctional compound masterbatch having two or more isocyanate groups is included in an amount of 5.0 to 20.0 parts by weight based on 100 parts by weight of the total amount of the first pre-vitrimer and the second pre-vitrimer.

14. In the first paragraph, when the vitriol composition is molded into a sphere having a diameter of 1.55 to 1.63 inches, the sphere has a coefficient of restitution (COR) of 0.800 or more and a compression ratio of 105 or less. The above coefficient of restitution is determined by dividing the rebound velocity by the initial velocity when the ball is fired at a speed of 125 feet per second at a steel plate located 3 feet away from the initial velocity measurement point. 15.(i) A step of obtaining a first pre-vitrimer by subjecting a first thermoplastic polyurethane elastomer having a Shore D hardness of 30 to 40 and a multifunctional compound having two or more alcohol groups to an ester exchange reaction in the presence of a zinc (Zn)-based catalyst; (ii) a step of obtaining a second pre-vitrimer by subjecting a second thermoplastic polyurethane elastomer having a Shore D hardness of 45 to 60 to a transesterification reaction of a multifunctional compound having two or more alcohol groups under a zinc (Zn)-based catalyst; and (iii) A method for producing a vitrimer composition, comprising a step of partially cross-linking a mixture of the first pre-vitrimer and the second pre-vitrimer obtained in the above steps (i) and (ii) with a multifunctional compound masterbatch having two or more isocyanate groups.

16. A method for producing a bitrimer composition in claim 15, wherein the ester exchange reaction of steps (i) and (ii) is performed under melt conditions in an extruder, and the partial crosslinking of step (iii) is performed under melt conditions in at least one of an injection molding machine and a mold.

17. A method for producing a bitrimer composition in which injection molding is performed simultaneously with partial cross-linking in step (iii) of paragraph 15.

18. A golf ball comprising a core, a cover layer, and at least one mantle layer present between the core and the cover layer, wherein the cover layer is formed of a vitrifier composition according to any one of claims 1 to 14.

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