JPH0693930B2 - Golf ball - Google Patents

Description

TECHNICAL FIELD The present invention relates to a golf ball having high surface durability.

(Prior Art) A golf ball is a wound golf ball or a solid golf ball, a white paint is applied to the surface, and then a clear paint is applied. The role of this paint is to protect the cover material and impart gloss and whiteness to the ball to improve its aesthetics.

The properties required for this type of golf ball paint are impact resistance to withstand repeated impacts from golf clubs, excellent sand abrasion resistance, weed stain resistance, weather resistance that does not discolor even when exposed to sunlight for a long time, and Water resistance and the like. The paint for golf balls currently used to satisfy the above characteristics is a two-component urethane paint that cures a polyfunctional isocyanate curing agent and a hydroxyl group-containing polyester at room temperature using a catalyst. In this case, the polyester is It is an ester polymer of an ordinary polyhydric carboxylic acid and an aliphatic polyhydric alcohol.

(Problems to be solved by the invention) A golf ball coated with a conventional paint has a small surface film elongation at break and poor recovery after deformation. . In addition, rolling contact with sand or soil occurs at the time of bunker shot, etc., but the scratches and abrasion due to this tend to be lost, and the gloss and aesthetics of the golf ball tend to be lost. That is, the conventional one lacks in surface durability that affects the appearance or aesthetics of the golf ball.

(Means for Solving Problems) The inventors of the present invention significantly improved the above-mentioned drawbacks by using a hydroxyl group-containing polyester having a isocyanurate ring as a part of the polyhydric alcohol component constituting the urethane coating. It was found that a highly durable golf ball can be obtained.

That is, the present invention is a two-part curing type containing a hydroxyl group-containing polyester obtained by the reaction of a polyhydric alcohol component containing a polyhydric alcohol having at least a part of an isocyanurate ring and a polyvalent carboxylic acid, and a non-yellowing diisocyanate. Provided is a golf ball coated with a polyurethane paint and having high surface durability.

Polyhydric alcohols having an isocyanurate ring satisfy the formula: [In the formula, R represents hydrogen, an alkyl group having 1 to 5 carbon atoms or a hydroxyalkyl group having 1 to 5 carbon atoms, R'and R "are the same or different and each represents an alkylene group having 1 to 5 carbon atoms. The preferred example is Tris-2-.
Hydroxyethyl isocyanurate may be mentioned.

In the present invention, the polyhydric alcohol having an isocyanurate ring is at least part of the polyhydric alcohol component of the polyester. The polyhydric alcohol having an isocyanurate ring is present in the polyhydric alcohol component in an amount of at least 2% by weight, preferably 5 to 30% by weight. When it is less than 2% by weight, high surface durability is not imparted. As other polyhydric alcohols, aliphatic polyhydric alcohols conventionally used, for example, ethylene glycol, diethylene glycol, triethylene glycol, butylene glycol, neopentyl glycol, trimethylolpropane, glycerin,
Hexanetriol, a mixture thereof, or the like can be given. The polyhydric alcohol is preferably a diol, but a higher polyhydric alcohol is partially mixed in for introducing a crosslinking point. As the higher polyhydric alcohol, a triol among the above polyhydric alcohols having an isocyanurate ring may be used.

Polycarboxylic acids are the same as conventional ones. Examples of these include aliphatic polycarboxylic acids such as adipic acid, glital acid and dimer acid; alicyclic polycarboxylic acids such as tetrahydrophthalic acid and cyclohexanedicarboxylic acid; aromatic polycarboxylic acids such as phthalic acid. An acid, a mixture thereof, or the like can be given. Aliphatic and alicyclic polycarboxylic acids are preferred. Aromatic compounds are not preferable because they may yellow.

The hydroxyl group-containing polyester is obtained by subjecting the above components to an esterification reaction. The molecular weight of the obtained polyester was 2,000 to 1 by weight average molecular weight measured by gel permeation chromatography (GPC) of polystyrene standard.
Those of 0,000 are preferred. The hydroxy value of the polyester is 50 to 250, preferably 100 to 150. The blending amounts of the polyhydric alcohol and the polycarboxylic acid are determined so as to have the hydroxyl value as described above.

The non-yellowing type diisocyanate used as a curing agent in the present invention specifically means an aliphatic or alicyclic diisocyanate. Examples of such things are hexamethylene diisocyanate, hydrogenated xylyl diisocyanate,
It is used alone or as a mixture as a biuret body such as isophorone diisocyanate, an adduct body or a trimer body. The curing agent is added in such an amount that the ratio of the isocyanate group of the curing agent to the terminal hydroxyl group of the hydroxyl group-containing polyester is in the range of 0.8 to 1.6 equivalents.

The polyurethane paint is a low temperature curing type and a two-component type. In this case, the curing agent and polyester are divided into two liquids.

If necessary, various additives such as a curing catalyst such as dibutyltin dilaurate and stannas octoate, a leveling agent, an optical brightener, and an ultraviolet absorber may be added to the polyurethane paint. Also, a solvent may be blended to adjust the viscosity and the like. Examples of solvents are toluene, xylene,
Examples thereof include ethyl acetate, butyl acetate, methyl isobutyl ketone, methyl ethyl ketone and ethyl glycol acetate.

The above-mentioned two-component type urethane paint is usually used as a clear paint, and is applied onto a golf ball painted in white. In some cases, a golf ball may be coated with a pigment or the like to be enamel-coated and then applied.

For coating, the above-mentioned two-component type urethane paint is mixed, a golf ball is dipped, and then dried and cured at room temperature or a temperature of 70 ° C. or lower.

(Effects of the Invention) The golf ball of the present invention is less likely to have surface durability, for example, face mark scratches, cracks, and cracks of a golf club, and scratches and wear are reduced even when rotating contact with soil or sand occurs. Therefore, an excellent golf ball having a long-lasting gloss and aesthetic appearance can be obtained.

(Examples) The present invention will be described in more detail with reference to Examples.

Examples 1 and 2 Polyesters were synthesized from polyhydric alcohols and carboxylic acids having the following compositions.

Ingredient % by weight neopentyl glycol 30.0 triethylene glycol 14.0 tris 2-hydroxyethyl 5.0 isocyanurate adipic acid 47.0 tetrahydrophthalic acid 4.0 The polyester resin is prepared by mixing the above components and heating at 200 to 250 ° C for 4 to 5 hours for esterification. Got

The resulting polyester resin has an acid value of 6 and a hydroxyl value of 120.
And the molecular weight (GPC) M _w = 4800, Mn = 2000.

The resin produced is methyl isobutyl ketone / xylene = 50
It was dissolved in a mixed solvent of / 50 to prepare a base resin varnish having a nonvolatile content of 80%. This is referred to as base material 1.

Preparation of paint and coating on golf ball Base 1, curing agent and curing catalyst dibutyltin dilaurate were mixed at the ratio shown in Table-1, and further diluted with a thinner to a nonvolatile content of 35%.

1.68 inch 2 after white paint painting, mark stamp
-A piece golf ball was painted with an automatic spray gun.
The spraying amount was adjusted so that the thickness of the coating film was about 15 μm. Drying was performed at 40 ° C. for 24 hours. Further, it was stored at room temperature for 2 hours and used for the test.

Comparative Examples 1 and 2 In the composition of the above Examples, tris-2hydroxyethyl isocyanurate was changed to trimethylolpropane, and the ones synthesized so that the hydroxyl value and the molecular weight were almost the same as those of the base 1 were used. Dissolved in a mixed solvent of methyl isobutyl ketone and xylene 50/50, non-volatile content 80 wt%
The resin varnish of was produced. This is used as base 2. The curing agent is the same as in the example, Burnock DN-950, Burnock DN.
Using -980, a paint having the composition shown in Table 2 was prepared and applied to a golf ball of the same type as that of the example so that the film thickness was about 15 μm. The coating film was dried at 40 ° C. for 24 hours and then left at room temperature for 2 weeks, and various tests were conducted.

Example (1) Impact resistance test with a golf club A swing machine manufactured by Through Temper was used with a driver and 5
45 m / s each with attached irons. The number of hits until the impact surface damage such as cracks on the ball surface and scratches by grooves on the club face occurred was determined by hitting the same place on the ball at a head speed of 37 m / s. The results are shown in Table-3.

(2) Abrasion resistance test 5 balls, 500 g of sand for bunker and 1 hour of water were milled for 1 hour in a ball mill pot with an internal volume of 3 l, and the amount of abrasion loss due to sand and the degree of surface damage were examined. . The results are shown in Table-4.

(3) Actual shooting test by a professional golfer A bunger shot with a sand wedge and a rough shot with a 9 iron were actually performed by a professional golfer to compare the state of sand adhesion, surface scratches, cracks, and cracks, The results are shown in Table-5.

Claims (5)

[Claims] 1. A two-part curable type containing a hydroxyl group-containing polyester obtained by reacting a polyhydric alcohol component containing a polyhydric alcohol having at least a part of an isocyanurate ring with a polyvalent carboxylic acid, and a non-yellowing diisocyanate. Golf ball painted with polyurethane paint. 2. A golf ball according to claim 1, wherein the polyhydric alcohol having an isocyanurate ring is present in an amount of 5 to 30% by weight based on the whole polyhydric alcohol component. 3. A hydroxyl group-containing polyester has a weight average molecular weight.
The golf ball of claim 1 having 2,000 to 10,000. 4. The hydroxyl group-containing polyester has a hydroxyl value of 50 to 25.
The golf ball of claim 1, having 0. 5. The golf ball according to claim 1, wherein the polyurethane paint is a clear paint.