DE2203599A1 - Golf ball - Google Patents

Description

1555 Γ

PATENT LAWYERS

DR.-INQ. R. DÖRING DIPL.-PHYS. DR. J. FRICKE

BRAUNSCHWEIG MUNICH

UNIROYAL, Inc.

1230j Ave. of the Americas

New York 1οο2ο, Ν.Υ., / USA

"Golf ball"

The invention relates to a golf ball consisting of a core and a jacket, the core being made of a conventional wound Golf ball core or the recently developed solid unitary core.

Golf ball coats so far have been made of a number of different ones Materials have been manufactured. The main components used were natural transpolyisoprenes (natural balata or gutta-percha), synthetic transpolyisoprenes, thermoplastic resins such as polyethylene or polypropylene, and ionomer resins are used. The coats made from these materials showed however, some undesirable properties, among which in particular low fatigue strength, low wear resistance and bad behavior regarding "click" and "feel" should be highlighted. Many of these materials are pretty as well expensive and not easily recyclable for use as golf ball covers.

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In contrast, it is the object of the invention to develop a golf ball of the type described in more detail in such a way that a conventional one The core, regardless of the embodiment, can be covered with a jacket that has an extremely high resistance against damage caused by the impact of the golf club, however, shows the other important properties of a golf ball high quality not compromised.

This object is achieved according to the invention in that a mixture is used for the golf ball jacket or cover, which consists mainly of an ionomeric resin, but which Contains up to 2o parts of a sulfochlorinated polyethylene. This mass can easily be packed into a golf ball coat with all the desired properties are transferred. In particular, the new jacket material has the following properties:

a) It is thermoplastic with a relatively low melting temperature,

b) it does not require curing and vulcanization,

c) it's cheap,

d) it has a high fatigue strength and

e) it gives the golf ball good properties in terms of "click" and "feel".

The use of a caprolactone resin as a mixing agent in the shell compound can significantly reduce the compatibility of the sulfochlorinated

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PolyäthjLens and the ionomer resin improve without the rest Impact properties of the ball. The addition of this ingredient is beneficial, but not essential necessary.

The use of an ionomer resin alone in a golf ball cover material has already been described in US Pat. No. 3,454,280, However, a jacket made therefrom tends to split open at the seams when the ball passes through the golf club is hit. During play, these coats create a hard, stone-like feel when the ball is hit. The addition of sulfochlorinated polyethylene to the ionomer Jacket material greatly improves the adhesion of the seam and the feeling for the player when the ball is hit will. The hardness (Shore C) of the new jacket material is lower than that of the cladding material containing only the ionomer. This pactor contributes significantly to the improvement of the "feel" properties of the golf ball.

The ionomer component of the shell material is a well-known material and is described in detail in U.S. Patent No. 3,264,272, the Pil Patent 1 393 73o and Canadian patent 674,595 and ^1,713,631. In this regard, express reference is made to these publications. The term "ionomer" describes an ionic copolymer of at least 50 Mql- # of one or more oC olefins along with a minor proportion

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a £ , β ethylene-containing unsaturated modocarboxylic acid or dicarboxylic acid, the acid monomer content of the copolymer between 0.2 to 25 mol? amounts to. Uniformly distributed throughout the copolymer is at least one kind of metal ion having an ionic valence of 1-3 inclusive in the modocarboxylic acid-containing ionomer and a valence of 1 in the dicarboxylic acid-containing ionomer. At least Io % of the carboxylic acid groups of the copolymer are neutralized by the metal ions and exist in the ionic state. Ionomers based on the copolymers of ethylene and acrylic acid or methacrylic acid are the most common. The metal ions are usually ions of the metals of Groups I, II, III, IV-A and VIII of the periodic table. The most common of these are ions of the alkali metals, for example sodium or potassium, the alkaline earth metals, for example calcium, strontium and barium, or other metals, for example zinc or aluminum. The ionomers are hard, transparent, bar-like, thermoplastic materials.

The ionomers preferred in the context of the invention are those which are known under the trademark "Surlyn A", which ionic copolymers of approximately 96.5 mol-? of ethylene and 3.5 MoI-? of methacrylic acid and which ions of Sodium or zinc evenly distributed throughout the copolymer in an amount sufficient to be about 50% To effect neutralization of the methacrylic acid.

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The sulfochlorinated polyethylene component of the sheath composition may preferably be a material such as that disclosed in US Pat. No. 2,212,786 is described. Reference is expressly made here to this patent specification. These materials are produced by the reaction of a solid ethylene polymer having a molecular weight of at least 1, ooo and chlorine and sulfur iodide. Typical Sulphochlorinated polyethylenes, which are used as a sheath compound, are known under the trade name "Hypalon". This There are five different types of material on the market:

2o, 3o, 4o, 45 and 48

Each of these types contain a different percentage of chlorine and sulfur. Hypalon 2o contains 29 % chlorine and 1.4 % sulfur and gives optimal results when this material is combined with the preferred ionomer to form the new shell compound.

common sheaths for golf balls, especially those that based on the material Balata, can be applied to wound cores at temperatures in the range of 93 ° to 121 ° C will. Ionomers of the type used in the invention must be applied at higher temperatures, typically in the range of 121 ° C to about 177 ° C. Slabs or blanks of the coating material are first prepared and preheated immediately before molding. Each board or blank should be large enough to be one-half

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to form a finished coating. It should also contain sufficient additional material to enable the formation of a To enable foam burrs, which ensures reliable and good shaping. There is always a blank on each of the two pre-heated halves of the pom before insertion of the core applied in the lower half. The mold is closed very gradually in order to prevent the core from being buried avoid. Once the mold has closed, the mold and its contents are cooled. The finished ball is then made from the Press taken out and finely machined, painted, marked and packaged. The exact details of the molding cycle can vary depending on such factors as ball type, (wound or solid core), shell mass, foam press, Heating rate and cooling rate. Leave the details of time, closing speed and the like easily determined by a specialist. However, a typical cycle is given for the common equipment that is used in industry, using a press, the mold halves in a vertical direction one above the other are arranged. Such a molding cycle works as follows:

1. Preheating the press to a temperature of

149 ° C

2. Preheating of the jacket blank to a temperature between 121 ° and 149 ° C

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'τ 7 -

3. Insertion of a preheated blank into the two mold halves of each mold.

4. Insertion of a core into the lower mold half.

5. Slowly close the mold, allowing the excess cladding material to flow around the core leaves without it being able to burst (for this purpose Io see. after the first touch of the contents of the two mold halves required).

6. The press is closed and see on temperature for the duration of about Io. held to a to ensure a good bond between the two halves of the jacket.

7. The mold is cooled down (you can use Io to 30 minutes may be required depending on the mold design and the temperature of the coolant.

8. The press is opened and the ball is removed for further processing.

To further illustrate the invention, the following are provided Examples given. In these are all_components represented by their weight. It should be noted, however, that these examples are intended to be illustrative rather than limiting to serve the invention.

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example 1

The following materials (parts by weight) become more finer than usual Rubber mill mixed together

A B 1

loo loo Io Io Io

Surlyn A 1559 Titanium Dioxide Hypalon 2o

These mixtures are shaped into panels and finally applied to conventional cores wound from rubber threads. the Balls obtained therefrom were subjected to the fatigue strength testing device with the methods given below Results examined. The testing device for determining the fatigue strength is a machine that tests the ball with a hits a hard, constant blow and repeats this blow until the ball, due to jumps, deformations, Loosening of the jacket or the like. Changes which impair the puncture of the golf ball fails.

AWAY

+) Fatigue strength
(half life) 75 85 Shore C hardness 93 9o

Failure of the seam after 75 hits in a test series of 12 balls 5 1

+) The expression -half a life- determines the number of hits in a fatigue strength testing machine, which

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causes half of the balls in a given set of experiments to fail.

example 2 A. B. loo
5 9o
5
Io Surlyn A 1559
Titanium dioxide
Hypalon 2o

After mixing and shaping the golf ball in the manner of the In Example 1, the golf balls obtained were tested for fatigue strength with the following results:

A B fatigue strength (half

Life) loo 115

Surlyn A 1559 ¹ Titanium Dioxide Caprolactone PCL-700 Hypalon 2o

example 3 A. B. 9o loo 5 5 5
Io - oo ²

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- Io -

After mixing and molding the golf balls in the manner given in the example, the obtained golf balls were tested for fatigue strength examined. The result:

AB fatigue strength
(half a life) 55 6 ~ ö

Remark ;

1. The material "Surlyn A 1559" given in the examples is an ethylene-methacrylic acid copolymer in which up to 90 % of the acid halves are neutralized with metal ions, the majority of which are sodium ions. This material is described in U.S. Patent 3,264,272.

2. In the case of the "Capro-lactone" material used in the examples PCL 700 is the trade name for a product from Union Carbide Co., which is an average Has a molecular weight of 40,000. The term PCL-700 indicates a low viscosity, the manufacturing company but does not indicate how the viscosity is measured.

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Claims (3)

Claims _L ly golf ball with a core and a jacket, the jacket containing an ionomer based on the copolymers of ethylene and acrylic or methacrylic acid, characterized in that the jacket compound additionally contains up to 20 parts of a sulfochlorinated polyethylene. 2. Golf ball according to claim 1, characterized ei c h η e t that up to 10 parts of a caprolactone resin are added to the shell compound. 3. Golf ball according to claim 1 or 2, characterized in that the sulf © chlorinated polyethylene contains 29 % chlorine and 1.4 % sulfur. 209833/0048