GB2296014A

GB2296014A - Golf ball

Info

Publication number: GB2296014A
Application number: GB9425404A
Authority: GB
Inventors: Rene Moser; Stephan Wick
Original assignee: EMS Inventa AG; Inventa AG fuer Forschung und Patentverwertung
Current assignee: Inventa AG fuer Forschung und Patentverwertung; Uhde Inventa Fischer AG
Priority date: 1994-12-14
Filing date: 1994-12-14
Publication date: 1996-06-19
Also published as: GB9425404D0

Abstract

A golfball can be prepared in economic manner in various degrees of hardness and rebound properties. To this end, thermoplastic polyamide 6, PA 66, PA 11, PA 12, Grivory or polyamide elastomer with 0 to 3% foaming agent is used for the core (3) of the golfball, and a pulverulent filler (5) is mixed in for the establishment of the desired ball weight. According to a preferred embodiment, the pulverulent filler (5) comprises a metallic powder, so that lost golfballs can be located. <IMAGE>

Description

GOLFBALL This invention relates to a golfball that comprises a core and a covering surrounding the core.

Conventional golfballs of the type described above generally have a rubber core that is surrounded by a predominantly soft plastics covering. A distinction is drawn between so-called two-piece and three-piece balls, the former comprising a core of a rubber mixture, and the latter having a pre-stressed rubber yarn in several layers wound around a rubber core. The covering comprises highly impact-resistant ethylene copolymers, for both types of ball. According to current requirements, the diameter of such a golfball should not exceed 42.67 mm, while its weight is limited to 45.93 g. In order to achieve given flight characteristics of the golfball, substantially circular dimples are provided on the surface of the covering, whose size, number and position can be varied.

Further, in particular for the properties that are important for the flight or striking distance, particular degrees of hardness and a high rebound elasticity should be attained for the core construction. The preparation of this core for conventional golfballs described above, in consideration of the most exact provision of the requirement ball weight, is however somewhat complicated, time-consuming and expensive.

Further, it is often difficult to find lost balls again, once these have disappeared from the sight of a player.

It is therefore an object of the invention to provide a golfball of the type described above, which does not possess these disadvantages.

This problem is solved by the characteristics of the invention given in claim 1. In this context, polymers for the core of the golfball are preferably polyamide, EPDM and SEBS. Polyamide of the type PA 6, PA 66, PA 11, PA 12, polyamide elastomers of the polyetherpolyamide or polyetherester-polyamide of PA12-type and amorphous copolyamide of the Grivory type are especially preferred, with 0 to 3% foaming agent such as azodicarbonamide, and in which at least one filler for the provision of the desired ball weight is mixed therewith.

According to an advantageous embodiment, the core of the golfball has a foamed structure. According to a further advantageous embodiment, the filler comprises a metal powder, so that lost balls can be located. Bronze powder and iron powder are preferred for this purpose.

The advantages achieved by means of the invention are evident in that, with the proposed materials, golfballs with various degrees of hardness and good rebound properties can be prepared simply in the cost-effective injection moulding process. A further advantage lies in the simple establishment of the ball weight by mixing in at least one filler, whereby the proposed use of a metal powder as the filler, for the location of lost golfballs, according to a subclaim, is possible.

The invention will now be described by way of example only with reference to the accompanying drawing. Fig. 1 is cross-section through a golfball according to the invention.

Fig. 1 shows a covering 1 which comprises a foamed plastics material such as, for example, ethylene copolymer.

On the surface of the covering 1, substantially circular dimples 2 are provided, by means of which the flight properties of the golfball can be enhanced. A core 3, surrounded by the covering 1, comprises polymer 4. The polymer 4 is mixed with a filler 5, which preferably comprises a metal powder, in order to establish the desired ball weight. The metal powder can here be, for example, iron powder. The introduction of metal powder provides the possibility of locating and finding lost golfballs. using a suitable sensor.

According to the type and composition of the plastics material 4, different degrees of hardness and rebound characteristics can be achieved. In order to prepare the core 3, the cavity is used with a spring-loaded, adjustable batch on the discharge side, in order to avoid the formation of free streams of material. The golfball is preferably prepared in two passes, according to the multicomponent injection moulding process. In the first step, the core 3 is sprayed and then covered with the covering 1.

This can be conducted either with two separate injection moulding means and apparatus or with one injection moulding machine (two injection aggregates) and a transfer or rotation apparatus. The machine temperatures are established according to the specification sheets of the polymers.

In order to compare the physical properties with commercially-available golfballs, the parameter of the rebound/damping was determined using a fall test and the hardness/compression parameter by means of pressure resistance.

In the fall test, the golfball was allowed to fall through a height of 80 cm onto a V2A-steel support, and the rebound height was measured.

Using a scale of 1 to 100, the heights of the first, second and third rebounds of the golfball were measured.

Determination of the degree of hardness of the golfball was determined by means of the pressure loading of the necessary deformation in (N) for a compression of 1 mm, 3 mm, 5 mm and 10 mm.

In comparison with commercially-available golfball types, the golfballs according to the invention exhibited the comparative values shown in the following Table 1: Table 1

Ball Type Drop Test Rebound Compression Strength/Compression Ball Weight (Trade Name) Scale 100 Force (N) (g) Rebound Rebound Rebound 1 mm 3 mm 5 mm 10 mm Core Only 1 2 3 Titleist 100 Tour 81 60 41 900 1400 2800 8000 45.61 Slazenger 1/480 81 61 43 400 1400 2900 9500 45.49 Ram-Tour 4/90 86 63 46 600 2100 3800 8300 45.43 Ping EYE2 84 64 46 400 1500 3000 9800 45.99 Grilamid Polyamide 82 60 49 800 3200 6000 12200 43.3 Elastomer ELY 2702 with Bronze Powder without Propellant Grilamid Polyamide 72 46 28 600 1800 3000 6000 45.44 Elastomer ELY 2702 with Bronze Powder and 3% Propellant Degree of Foaming 20% ELY 2702* Polyetherester polyamide with low PA 12 content and linear polyetherdiamine ELY 2694* Polyetherester polyamide with average PA 12 content and linear polyetherdiamine ELY 2742* Polyetherester polyamide with high PA 12 content and linear polyetherdiamine Grivory* Amorphous copolyamide based on hexamethylenediamine/aromatic dicarboxylic acids *Producer EMS CHEMIE AG, Zurich, Switzerland

Claims

CLAIMS 1. A golfball comprising a core and a covering surrounding the core, wherein the core comprises a thermoplastic polymer containing a filler and 0-3% by wt.

of a foaming agent.
2. A golfball according to claim 1, wherein the polymer is selected from polyamides, EPDM and SEBS.
3. A golfball according to claim 1, wherein the polymer is selected from PA 6, PA 66, PA 11, PA 12, polyamide elastomers and Grivory.
4. A golfball according to claim 3, wherein the polyamide elastomer is a polyetherpolyamide or a polyetheresteramide.
5. A golfball according to claim 3, wherein the polyamide elastomer is based on PA 12.
6. A golfball according to any preceding claim, wherein the core has a foamed structure.
7. A golfball according to any preceding claim, wherein the covering comprises an impact-resistant ethylene copolymer.
8. A golfball according to any preceding claim, wherein the filler comprises a finely-divided metal, allowing location of the golfball.
9. A golfball according to claim 8, wherein the metal is bronze powder or iron powder.
10. A golfball according to any preceding claim, wherein the filler comprises a mineral filler, glass fibres or glass balls.
11. A golfball according to any preceding claim, obtainable in no more than two process stages, wherein the core is first prepared in an injection-moulding process, and the core is then surrounded with the covering.
12. A golfball according to any preceding claim, substantially as herein described with reference to the accompanying drawing.