JP2003144584A - Painted golf ball - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a painted golf ball which achieves excellent wear resistance after repeated hitting or washing with brushes. SOLUTION: The painted golf ball is produced by forming a covering of a paint on the surface of the body of the golf ball. The paint contains a polyethylene wax fine powder of 0.5 to 10.0 pts.wt. per 100 pts.wt. of a resin solid. To implement the present invention ideally, the polyethylene wax fine powder is 3 to 10 μm in the average particle size and the paint is a urethane resin based product, preferably having a single layer structure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coated golf ball which has a good appearance and is excellent in abrasion resistance after repeated impact and after brush cleaning.

[0002]

2. Description of the Related Art Usually, golf balls include solid golf balls such as one-piece golf balls, two-piece golf balls, and three-piece golf balls, and wound golf balls. In each case, paint is applied on the surface. . Its role is to protect the surface of the golf ball body or markings on the surface, to maintain whiteness and gloss for a long time, that is, to improve the appearance and abrasion resistance and abrasion resistance against sand etc. during bunker shots. Is the improvement of.

As a paint for golf balls, paints selected from urethane resins, polyester resins, epoxy resins, acrylic resins and the like are generally used. A paint layer having excellent durability is formed by applying these paints a plurality of times. Also, in terms of simplifying the painting process, it is possible to use paint with excellent drying properties.
It has also been proposed to form a paint layer having only one layer (Japanese Patent Laid-Open Nos. 9-59566 and 11-1469).
No. 30, etc.).

However, in the case of a golf ball which has a large number of hits and is repeatedly washed and used, such as a golf ball used in a golf ball practice field,
The requirements for wear resistance after repeated impact and brushing cleaning become strict. In particular, in the case of a paint layer formed of only one layer as described above, the marking peeling of the golf ball also occurs as the paint layer wears.

[0005]

SUMMARY OF THE INVENTION The present invention solves the problems of the conventional coated golf balls as described above, has a good appearance, and has excellent wear resistance after repeated impacts and after brushing and cleaning. An object is to provide an excellent painted golf ball.

[0006]

Means for Solving the Problems As a result of intensive studies aimed at achieving the above object, the present inventors have found that by using a specific amount of finely powdered polyethylene wax in a paint,
It has been found that a coated golf ball having a good appearance and excellent in abrasion resistance after repeated impact and brushing cleaning can be provided, and the present invention has been completed.

That is, the present invention is a coated golf ball having a surface of a golf ball body coated with a paint, wherein the paint contains 0.5 to 0.5 parts of fine powder polyethylene wax with respect to 100 parts by weight of resin solid content. The present invention relates to a coated golf ball containing 10.0 parts by weight.

In the coated golf ball of the present invention, by using the finely powdered polyethylene wax for the paint, the above-mentioned polyethylene wax which is hard when the paint is hardened is present on the surface of the paint layer, and the surface hardness is increased to improve the abrasion resistance. An excellent coated golf ball can be obtained.

In order to preferably carry out the present invention, the finely powdered polyethylene wax has an average particle size of 3 to 10 μm; the paint is a urethane resin paint; and the paint has a single-layer structure. preferable.

As used herein, the term "golf ball body" refers to the golf ball itself which has not been painted, and has a large number of dimples on its surface. By "painted golf ball" is meant a golf ball having a paint layer with paint applied on the body of the golf ball.

The golf ball of the present invention is not dependent on the structure and may be a solid golf ball such as a one-piece ball, a two-piece ball, a multi-piece ball of three or more pieces, or a wound golf ball.

In the case of a solid golf ball, the core (solid core) used in the one-piece golf ball or the solid golf ball may be one conventionally used, for example, 100 parts by weight of a base rubber such as polybutadiene rubber. On the other hand, α, β-unsaturated carboxylic acids having 3 to 8 carbon atoms such as acrylic acid and methacrylic acid, or their monovalent or divalent metal salts such as zinc and magnesium, and trimethylolpropane trimethacrylate. 10 to 60 parts by weight of a vulcanizing agent (crosslinking agent) composed of the functional monomer described above, 0.5 to 5 parts by weight of a co-crosslinking initiator such as organic peroxide, filling with zinc oxide, barium sulfate or the like. The rubber composition containing 10 to 30 parts by weight of the material, if necessary, an antioxidant and the like is uniformly kneaded using an appropriate kneading machine such as an ordinary kneading roll, It can be obtained spherical core by vulcanization molding the inner. The conditions at this time are not particularly limited, but usually 130 to 240 ° C., pressure 2.9 to 1
It is performed at 1.8 MPa for 15 to 60 minutes. The surface of the obtained core is preferably buffed in order to improve the adhesion with the cover around it. Furthermore, the solid core may have a single-layer structure or a multi-layer structure of two or more layers.

Further, the core used in the thread-wound golf ball (thread-wound core) may be one conventionally used, and a thread formed by winding a thread rubber in a stretched state around the center. It consists of a rubber layer. Liquid center (liquid center)
Alternatively, any rubber type (solid center) may be used. The thread rubber wound on the center may be the same as that conventionally used in the thread wound layer of a thread wound golf ball. For example, natural rubber or natural rubber and synthetic polyisoprene may have sulfur or vulcanization. You may use what was obtained by vulcanizing the rubber composition which mix | blended an auxiliary agent, a vulcanization accelerator, an antioxidant, etc. The rubber thread is stretched about 10 times on the center and wound to form a wound core. However, these solid cores and wound cores are merely examples, and the present invention is not limited to these.

A cover layer is coated on the core obtained as described above. The cover material is a thermoplastic resin such as an ionomer, balata or hard rubber, which is usually used for a cover of a golf ball. It is not particularly limited as long as it is, but since the ionomer cover golf ball contains a free carboxyl group in the ionomer itself, it exhibits excellent adhesion to a paint and is most suitable.

When molding the golf ball body,
A dimple called a dimple may be formed on the surface, and a marking stamp or the like may be provided if necessary. Before the clear paint layer is applied to the surface of the golf ball body, it is desirable to appropriately polish the surface of the golf ball body to improve the adhesion of the paint.

Next, on the surface of the golf ball body,
Form a paint layer. In the coated golf ball of the present invention, the above-mentioned paint is required to contain 0.5 to 10.0 parts by weight of finely powdered polyethylene wax with respect to 100 parts by weight of resin solid content, preferably 0.7 to 7 parts. ．
0, more preferably 1.0 to 5.0 parts by weight. If the amount of the finely powdered polyethylene wax is less than 0.5 parts by weight, the effect of improving abrasion resistance cannot be sufficiently obtained, and if it exceeds 10.0 parts by weight, the paint becomes cloudy and the transparency is lowered.

In the coated golf ball of the present invention, it is desirable that the finely powdered polyethylene wax used in the above paint has an average particle size of 3 to 10 μm, preferably 5 to 8 μm, more preferably 6 to 8 μm. If the average particle diameter is less than 3 μm, the effect of improving wear resistance cannot be sufficiently obtained, and if it exceeds 10 μm, the smoothness of the paint layer is deteriorated.

The finely powdered polyethylene wax used in the paint of the present invention is not particularly limited as long as it has an average particle diameter within the above range and imparts desired abrasion resistance to the coated golf ball obtained. Examples thereof include low-density to high-density polyethylene wax and oxidized polyethylene wax. Regarding the form of addition to the paint, fine powder may be added as it is, or may be in a state of being dispersed in a solvent or the like, for example, a liquid form or a paste form.

As the paint used in the present invention, urethane resin, epoxy resin, acrylic resin, polyester resin type paint, etc. can be used, but urethane resin type paint is preferable, and the adhesion to the base is taken into consideration. It is desirable to select it. As the urethane resin paint, a two-component urethane paint composed of a main agent and a curing agent is used. In the main component of the urethane resin-based paint, the main component is the polyol component. Then, the polyol component contains a specific urethane polyol as shown below.

Urethane polyol is synthesized by the reaction of a polyisocyanate compound and a polyol. As the polyisocyanate compound used to synthesize,
There is no particular limitation as long as it has two or more isocyanate groups. For example, hexamethylene diisocyanate (HD
I), aliphatic such as xylylene diisocyanate (XDI), hydrogenated xylylene diisocyanate (H ₆ XDI), isophorone diisocyanate (IPDI), tetramethyl xylylene diisocyanate (TMXDI), hydrogenated diphenylmethane diisocyanate (H ₁₂ MDI),
Examples thereof include alicyclic, aromatic and araliphatic diisocyanate compounds. Among these, non-yellowing polyisocyanates (aliphatic and alicyclic polyisocyanates) are preferably used from the viewpoint of weather resistance.

The polyol used for producing the urethane polyol may be a low molecular weight compound or a high molecular weight compound as long as it has a plurality of hydroxyl groups.
Examples of the low molecular weight polyol include ethylene glycol, diethylene glycol, triethylene glycol, butylene glycol, 1,3-butanediol,
1,4-butanediol, neopentyl glycol,
Diols such as 1,6-hexanediol; glycerin,
Triols such as trimethylolpropane and hexanetriol can be mentioned. As a high molecular weight polyol,
Polyether polyols obtainable by the reaction of an alkylene oxide with an initiator having an active hydrogen source;
Condensation type polyester polyol obtained by dehydration condensation of dibasic acid such as adipic acid and glycol or triol; Lactone type polyester polyol obtained by ring-opening polymerization of lactam such as ε-caprolactam; Polycarbonate synthesized using cyclic diol A diol; a polymer polyol such as an acrylic polyol obtained by appropriately introducing a hydroxyl group into an acrylic copolymer can be mentioned. Examples of the polyether polyol include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and the like, examples of the condensation type polyester polyol include polyethylene adipate, and examples of the lactone type polyester polyol include poly-ε-caprolactone. Can be mentioned.

Among the above polyols, those having a weight average molecular weight of 50 to 2,000, particularly 100 to 1,
A polyol of about 000 is preferably used. In addition, you may use these polyols individually or in mixture of 2 or more types.

The urethane polyol is a polyol having a hydroxyl group at both ends, which is formed by a reaction between the diisocyanate compound and the polyol to form a urethane bond. Here, the ratio of urethane bonds in the urethane polyol is 0.1 to 5 mmol / g with respect to 1 g of the urethane polyol.
Is preferred. The ratio of urethane bonds is related to the rigidity of the paint layer formed, and is 0.1 mmol /
This is because if it is less than g, the urethane concentration in the paint layer to be formed becomes small and the abrasion resistance is poor. Meanwhile, 5
When it exceeds mmol / g, the paint layer becomes too hard and the followability to the deformation of the ball body is lowered, and thus cracks are likely to occur.

The weight average molecular weight of the urethane polyol is 4,000 or more, preferably 4,500 or more.
It is less than 000, preferably 9000 or less. 4,
If it is less than 000, it takes a long time to dry and the workability and the productivity are lowered. On the other hand, in the case of a urethane polyol having a high molecular weight of 10,000 or more, the OH value of the urethane polyol is relatively small, the reaction amount after coating is small, and the adhesion to the base is lowered. Further, if the weight average molecular weight is 9,000 or less, it is possible to form a dense paint layer with less deterioration of paint layer adhesion even in the state of being wet with water.

The hydroxyl value of urethane polyol is 15 mg
KOH / g or more, especially 73 mg KOH / g or more, 13
It is preferably 0 mgKOH / g or less, and particularly preferably 120 mgKOH / g or less. Below 15 mg KOH / g,
This is because the amount of reaction with the curing agent becomes too small and the adhesion strength with the ball body cannot be obtained. On the other hand, 130 mgK
If it exceeds OH / g, it takes time to react with the curing agent,
This is because the drying time becomes long, the productivity is lowered, and cracks are likely to occur at the time of impact.

In the urethane polyol as described above, a urethane bond is formed by diluting a raw material polyol with a solvent and gradually adding an isocyanate compound in a state where a reaction catalyst (for example, dibutyltin laurate) is added. The compound has a hydroxyl group at the terminal. The urethane bond ratio can be adjusted by adjusting the molecular weight of the starting polyol, the mixing ratio of the polyol and the isocyanate, and the like.

It is preferable that the polyol component constituting the main agent of the present invention is the above-mentioned specific urethane polyol itself, that is, the main agent is substantially the above-mentioned specific urethane polyol. A polyol that is compatible with and does not have a urethane bond may be included.

The polyol that can be used in this case may be a polyol that can be used in the synthesis of urethane polyol, that is, any of low molecular weight diols, triols, or polymer polyols. Specifically, ethylene glycol, diethylene glycol,
Triethylene glycol, butylene glycol, 1,3
-Low molecular weight diols such as butanediol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol; low molecular weight triols such as glycerin, trimethylolpropane and hexanetriol; polyethylene glycol, polypropylene glycol, polytetramethylene Examples thereof include polyether polyols such as glycols and condensation type polyester polyols; lactone type polyester polyols; polycarbonate diols; acrylic polyols.

When the base material contains a polyol having no urethane bond, the content of the urethane polyol in the base material is preferably 50% by weight or more, and more preferably 80% by weight or more. If the urethane polyol content is less than 50% by weight, the urethane polyol content is relatively low, and the drying time becomes long.

The curing agent used in the paint of the present invention is
Polyisocyanate compound, specifically, hexamethylene diisocyanate (HDI), xylylene diisocyanate (XDI), hydrogenated xylylene diisocyanate (H ₆ XDI), isophorone diisocyanate (IPD)
I), tetramethylxylylene diisocyanate (TM)
XDI), hydrogenated diphenylmethane diisocyanate (H
₁₂ MDI) and the like, aliphatic, alicyclic, aromatic, araliphatic diisocyanate compounds and the like, and of these, non-yellowing polyisocyanate compounds (aliphatic and alicyclic isocyanates) are preferable. These polyisocyanate compounds may be used alone or in combination of two or more.

The paint used for the coated golf ball of the present invention may further contain various additives and diluents in addition to the above components. Examples of additives include ultraviolet absorbers (deterioration prevention), antioxidants, light stabilizers, silicon-based slip agents, leveling agents, viscosity modifiers, optical brighteners,
Additives that can be generally contained in golf paints such as antiblocking agents, curing catalysts, and color pigments may be contained. Further, these additives may be contained in either the main component or the curing agent, and the compounding amount of the above additives is 0.1 to 10 parts by weight with respect to 100 parts by weight of the resin solid content.

Examples of diluents to be added to the paint include water, alcohols such as isopropyl alcohol, aromatics such as toluene, hydrocarbons such as hexane, esters such as ethyl acetate, and ketones such as methyl ethyl ketone. . The blending amount of the diluent is not particularly limited, but is 5 to 50.
% By weight.

The golf ball paint having the above composition is prepared by mixing the main agent and the curing agent immediately before use. Here, the mixing ratio is such that the equivalent ratio of the isocyanate group in the curing agent to the hydroxyl group in the main agent (isocyanate group / hydroxyl group) is 0.5 or more, preferably 0.9 or more, and 2.0 or less, preferably 1.5 or less. Is.

Such a paint can be used not only for coating the surface of the cover of a multi-piece golf ball such as a two-piece ball having a core covered with an ionomer cover, but also as a primer paint applied to the surface of the core. Alternatively, it may be used as a clear coat applied to the primer-coated surface. Further, even a golf ball having an ionomer cover may be a wound golf ball having a wound core or a solid golf ball having a rubber block. Further, the rubber core alone can be used as a surface paint of a one-piece golf ball constituting the ball body.

The coating method is not particularly limited, and a method for coating a two-component mixed paint such as an air spray gun or electrostatic coating on a golf ball which has been surface-treated by washing after mixing the main component and the curing agent. A conventionally known method can be used as When coating with a spray gun, the main agent and the curing agent may be mixed little by little, or a two-liquid stoichiometric pump may be used to provide a paint transport path immediately before the spray gun, such as a static mixer. The two liquids may be continuously mixed at a constant ratio through a line mixer, or an air spray system equipped with a mixing ratio control mechanism may be used.

Since it has almost no effect on the properties of the cover or the rubber, it is preferable to dry and cure at a temperature of less than 50 ° C. for 0.5 to 2 hours after application. As a result, it is possible to form the urethane-based hard paint layer without lowering the productivity and without causing plasticization or the like on the cover.

In the coated golf ball of the present invention, the paint layer may have a single-layer structure or a multi-layer structure of two or more layers, but the single-layer structure simplifies the coating process. It is preferable because it is performed. The paint used for the coated golf ball of the present invention is improved in abrasion resistance by using a specific amount of finely powdered polyethylene wax as described above, and therefore, it is not necessary to form the paint layer into a multi-layer structure. It is possible to achieve a coated golf ball having a good appearance even with a paint layer having a layered structure and having excellent abrasion resistance.

In the coated golf ball of the present invention, the paint layer has a thickness of 6 to 25 μm, preferably 8 to 20 μm.
It is desirable to have m. The thickness of the paint layer is 6
If it is less than μm, the paint layer tends to be worn away during continuous use, and if it is more than 25 μm, the effect of dimples is deteriorated and the flight performance of the golf ball is deteriorated.

At present, the ball weight is specified to be 45.92 g or less in the case of a large size ball, but
There is no standard for the lower limit. The golf ball of the present invention is
Weight 44.0-45.8g, preferably 44.2-4
Having 5.8 g. When the weight of the ball is less than 44.0 g, inertia during flight is lost, and the ball stalls in the latter half of the flight to reduce the flight distance. When it is more than 45.8 g, the shot feeling becomes heavy and bad.

The golf ball of the present invention has a diameter of 4
The thickness can be 1.0 to 44.0 mm, but it is preferably 42.67 mm or more, which is suitable for the specifications of large size balls, and is usually about 42.75 mm.

[0041]

EXAMPLES Next, the present invention will be described in more detail by way of examples. However, the present invention is not limited to these examples.

(I) Two-piece golf ball (Examples 1 to 1)
5, 11 to 12 and Comparative Examples 1 to 3) Preparation of core A rubber composition for a core having a composition shown in Table 1 below is kneaded and heated and pressed at 160 ° C for 13 minutes in upper and lower molds having a hemispherical cavity. Thus, a spherical core having a diameter of 39.3 mm was obtained.

[0043]

[Table 1]

(Note 1) Product name "BR1" from JSR Corporation
1 ”commercially available polybutadiene rubber

Preparation of Cover Composition (Cover Formulation A) Materials having the formulations shown in Table 2 below were mixed by a twin-screw kneading extruder to prepare a pellet-shaped cover composition. Extrusion conditions are screw diameter 4
5 mm, screw rotation speed 200 rpm, screw L
/ D = 35, the formulation is 20 at the extruder die position.
Heated to 0-260 ° C.

[0046]

[Table 2]

(Note 2) Trade name, sodium ion neutralized ethylene-methacrylic acid copolymer type ionomer resin manufactured by Mitsui DuPont Polychemical Co., Ltd. (Note 3) Trade name, zinc ion manufactured by Mitsui DuPont Polychemical Co., Ltd. Neutralized ethylene-methacrylic acid copolymer type ionomer resin (Note 4) Trade name, sodium ion neutralized ethylene-methacrylic acid copolymer type ionomer resin manufactured by Mitsui DuPont Polychemical Co., Ltd.

Preparation of Golf Ball Body A cover layer was formed by directly injection-molding the above-mentioned cover composition onto the core obtained as described above to prepare a two-piece golf ball body having a diameter of 42.7 mm. did. The upper and lower molds for molding the cover have hemispherical cavities, are provided with dimples, and part of the dimples also serves as a hold pin capable of advancing and retracting. The above-mentioned hold pin is ejected, the core is thrown in and held, and the resin heated to 210 ° C. is injected into the mold clamped with a pressure of 80 tons in 0.3 seconds, cooled for 30 seconds and the mold is opened to open the golf ball. Took out.

(Ii) One-piece golf ball (Example 6-
10, 13 to 14 and Comparative Examples 4 to 6) The rubber compositions having the compositions shown in Table 3 below are mixed and kneaded.
Diameter of 4 by pressing in the upper and lower molds having a hemispherical cavity with dimples at 160 ° C for 30 minutes
A one-piece golf ball body having 2.7 mm was made.

[0050]

[Table 3]

(Note 1) Product name "BR1" from JSR Corporation
1 ”commercially available polybutadiene rubber (Note 5) from Sumika Color Co., Ltd. under the trade name“ BLUE LB
5TO15 ”, a commercially available blue pigment

After the surface of the golf ball main body obtained by paint coating is polished, the golf ball main body marked with a pad stamp is marked with "A mixture of a polyether polyol and a polyester polyol (a hydroxyl group as a main component). Value: 82 mg KOH / g, hexamethylene diisocyanate as a curing agent, NCO: OH in an equivalent ratio of 1.
The two-part type urethane clear paint mixed to have a ratio of 2: 1.0 "is shown in Tables 4 and 5 (Examples) and Table 6
(Comparative Example) A clear paint having a composition using the finely powdered polyethylene wax (molecular weight 5,000, softening point 120 ° C.) shown in (Comparative Example) was prepared, air gun coated, dried and cured to obtain a coated golf ball. It was The dry curing conditions were 40 ° C. × 60 minutes. The paint layer obtained had a thickness of 10 μm. With respect to the obtained coated golf ball, the appearance and the appearance of the paint layer and the marking after repeated impact and after brushing abrasion were evaluated, and the results are shown in the same table. The test method was as follows.

(Test Method) (1) Appearance Appearance was evaluated by visually observing the surface of the coated golf ball after paint painting. The evaluation criteria are as follows. Evaluation Criteria: The paint layer surface is smooth. X: The surface of the paint layer is inferior in smoothness and there is a feeling of strangeness.

(2) Appearance after repeated striking Iron No. 5 club (I # 5) was attached to a swing robot manufactured by Trutemper Co., and each coated golf ball was repeatedly striked 150 times at a head speed of 34 m / sec. And the abrasion state of the marking was evaluated by visual observation. The evaluation criteria are the following four levels. Evaluation criteria (paint layer) ⊚: No peeling of paint layer ○: Peeling area of paint layer is 5% or less of the total paint layer area Δ: Peeling area of paint layer is more than 5% and 20% or less of the total paint layer area × : The peeled area of the paint layer is 20% of the total paint layer area
Evaluation criteria exceeding (marking) ◎: No marking peeling ○: Marking peeling area is 5% or less of the total marking area △: Marking peeling area is more than 5% and 20% or less of the total marking area ×: Marking peeling Area is 20% of total marking area
Over

(Test result)

[Table 4]

[0056]

[Table 5]

[0057]

[Table 6]

From the above results, the coated golf balls of the present invention of Examples 1 to 7 are superior to the golf balls of Comparative Examples 1 to 6 in abrasion resistance after repeated impact and after brushing and washing, and their appearances. Was found to be good.

On the other hand, the golf balls of Comparative Examples 1 and 4 were excellent in appearance but were extremely inferior in wear resistance because fine powder polyethylene wax was not mixed in the paint. The golf balls of Comparative Examples 2 and 5 contained a small amount of finely powdered polyethylene wax, and thus were slightly better than the golf balls of Comparative Examples 1 and 4, but still poor in abrasion resistance. Since the golf balls of Comparative Examples 3 and 6 contained a large amount of fine powder polyethylene wax, they were excellent in wear resistance but poor in appearance.

[0060]

EFFECTS OF THE INVENTION The coated golf ball of the present invention has a good appearance by using a specific amount of finely powdered polyethylene wax in the paint and is excellent in abrasion resistance after repeated impacts and after brushing cleaning. It was possible to provide a golf ball.

Claims (4)

[Claims] 1. A coated golf ball having a surface of a golf ball body coated with a paint, wherein the paint is 0.5 to 10.0 parts by weight of finely powdered polyethylene wax with respect to 100 parts by weight of a resin solid content. A coated golf ball, characterized by containing a part. 2. The coated golf ball of claim 1, wherein the finely powdered polyethylene wax has an average particle size of 3 to 10 μm. 3. The coated golf ball according to claim 1, wherein the paint is a urethane resin-based paint. 4. The coated golf ball according to claim 1, wherein the paint has a single-layer structure.