WO1992001493A1

WO1992001493A1 - A sports ball

Info

Publication number: WO1992001493A1
Application number: PCT/AU1991/000323
Authority: WO
Inventors: Stephen John Defina; Warick Patrick Askew
Original assignee: Glo Sports International Pty Limited
Priority date: 1990-07-25
Filing date: 1991-07-19
Publication date: 1992-02-06
Also published as: JPH05508788A; GB2261607A; AU8223191A; GB9301412D0

Abstract

A phosphorescent sports ball, particularly a golf ball and a tennis ball, is disclosed in which a phosphorescent pigment is added to a plastics component of the ball. The adding can be by way of incorporation within the plastics material or the dyeing of plastics in fibrous form. Prior art phosphorescent balls were painted and thus subject to scuffing. The preferred pigment is ZnS:Cu.

Description

A SPORTS BALL

The present invention relates to sports balls and, in particular, to golf and tennis balls. However, the Invention is not limited to balls used in these two particular sports.

BACKGROUND ART

There has long been a need for a mechanism which enables

essentially outdoor games such as golf and tennis to be played for greater lengths of time in order to best utilize the capital cost of the outdoor playing facilities. This requires that twilight and/or night time use of such facilities be possible. One proposal for such extended playing times is contained in the specification of International Patent Application No. PCT/AU88/00324 published under no. WO 89/01810 in which a playing surface having luminescent portions is used and the playing area is illuminated with ultraviolet light.

It is also known from Australian Patent No. 533145 (previously Application No. 10219/83) to provide for a golf ball with a fluorescent cover, the fluorescent pigments and dyes used in the cover being commercial products available from the Dayglo Color Corporation of the USA or Lawter Chemical Co of Skokie, Illinois, USA.

However, it has been determined in practice that fluorescent balls are not sufficiently visible after dark on a golf course, for example, because the intensity of radiation from the ultraviolet light sources is relatively low. Accordingly, the intensity of the re-emitted visible radiation from the fluorescent balls is also low.

It is also known to use a golf ball (manufactured by PICK POINT SPORTS of Florida, USA) with a stick or rod of two chemical materials separated by a frangible portion which, after being subjected to a predetermined bending, breaks allowing the two chemicals to mix thereby emitting light. Such materials are sold under the registered trade mark CYALUME of American Cyanamid Company of Bound Brook NJ USA. This stick or rod is inserted into the ball along a centrally aligned hole, however, this ball suffers from the disadvantage that it does not behave

mechanically or aerodynamically like a conventional golf ball. It is also relatively expensive since the emitted light lasts only 4 hours and then the stick (which costs approximately A$2.00) must be discarded.

In order to overcome these problems, it has been proposed to use a golf ball painted with a phosphorescent paint. Such a ball can be

"charged" by being strongly irradiated with radiation and which therefore emits visible radiation for a relatively lengthy time during which the intensity of the emitted radiation decays. However, such painted phosphorescent balls suffered from the problem that they were "scuffed" during use. As a consequence a dark patch appeared at the location of the various hits and the illuminationintensity was rapidly reduced. Thus these balls did not emit sufficient light for a sufficient length of time to be of any practical use. In particular, these balls were uneconomic since experience indicated that after one game of golf the ball was not able to be used for night time play.

The object of the present invention is to provide a phosphorescent ball which provides an adequate optical performance and so can be used for outdoor sports at night time over a reasonable length of time, for example, at least several games..

SUMMARY OF THE INVENTION

According to one aspect of the presentinvention there is disclosed a phosphorescent ball for night time sporting and leisure activities, said ball comprising plastics to which during manufacture a

phosphorescent pigment has been added. The adding can be by way of impregnation or dyeing.

PREFERRED EMBODIMENTS

Preferred embodiments of the presentinvention will now be described with reference to the following examples.

EXAMPLE1

The first embodiment of the phosphorescent golf ball has an overall weight of 46.5 gm (1.64 ozs) and overall diameter of 4.27 cm (1.68 inches). The ball has a substantially conventional centre or core with a weight of 35.5 gm (1.25 ozs) and diameter of 3.81 cm (1.5 inches). The cover accordingly has a weight of 11 gm (0.39 ozs) and thickness of 0.23 cm (0.09inches) and it is formed from a blend of ionomer polymers

Including poly (ethylene-co-methacrylic add) and those sold by Du Pont under the name SURLYN.

To the cover material is added a phosphorescent pigment having a weight of approximately 4 gm (0.14 ozs). Accordingly, the range of the pigment concentration in the cover material is from approximately 107. to approximately 50%, and preferably 257.-35%, by weight.

The preferred pigment is sold in Australia under the name LUMI-GSS by LEPCHEM AUSTRALIA PTY LIMITED and comprises phosphorescent zinc sulphlde (ZnS:Cu) crystals. A combination of phosphorescent pigments is able to be used provided the total weight of the pigment is in accordance with the above.

In addition, one or more clear coats can be added to the ball over the cover material. The preferred form of Inner clear coat is clear epoxy resin and the preferred form of outer clear coat is clear

urethane. Best results were achieved if no optical brighteners were present in the clear coats. Any Indicia can be applied to the ball between these two clear coats.

EXAMPLE2

Early experiments IIndicated that pigment concentrations below about 5% were entirely unsatisfactory since the glow duration was too short. In addition blotchy and uneven light effects were produced if scrap cover material was re-ground and added to the cover material during

fabrication. In order to overcome this problem, the ball as described in Example 1 was fabricated and virgin cover material at the appropriate pigment concentration was used. For subsequent batches scrap pigmented cover material could then be used without deleterious effect.

Furthermore, because of the weight of the pigment, the mass of the centre or core had to be reduced but the volume maintained. This problem was solved by the use of less dense fillers.

EXAMPLE3

Conventional inner cores for golf balls are of various colours such as pink, blue and grey. Since the colour of a conventional golf ball is determined by its outer cover which is both coloured and opaque, the colour of the inner core is irrelevant. It has been found that the optical performance of the balls of both Example 1 and 2 can be enhanced by increasing the reflectivity of the inner core. Improved results are obtained with a white, preferably brilliant white, inner core. Chrome plating to a mirror finish also is useful. The difference caused by the reflectiveinner core is only just discernable under normal light conditions, however, the difference in emitted light under no or low light conditionsi s quite marked.

EXAMPLE4

The abovementioned phosphorescent pigments take the form of a crystalline powder. The balls of Examples 1-3 where made by blending the ionomer and pigment together in a mill. The pigment crystals were added to the thermoplastic material which was softened by friction from the mill. After this mixing the material was allowed to cool and then was granulated. These granules were then placed in the injection moulding machine.

Although this produced an acceptable result, a much improved result was obtained by separately but simultaneously feeding the pigment and the ionomer into the screw feed of the injection moulding machine.

EXAMPLE 5

Any of the above described balls can also be provided with an additional phosphorescent layer. This is achieved by adding

phosphorescent pigment to thei nner clear coat of epoxy resin at a concentration of 10%-50% by weight. In this way any "scuffing" of the ball which does occur through use, does not result in a dark patch but instead results in a patch which is substantially equally phosphorescent as its surroundings.

EXAMPLE 6

The preferred embodiment of a tennis ball has a conventional elastomeric hollow interior which is provided with an outer cover made from fibrous material. The preferred material for the outer cover is a felt blend of 60% wool and 40% nylon by weight. The phosphorescent pigment is either attached to, or located within, the nylon during or before the fabrication of the nylon fibres. The pigment can also be attached to the wool fibres by, for example dyeing. A concentration of 20% by weight of the abovementioned phosphorescent plgment(s) was used.

EXAMPLE 7

A tennis ball having the conventional elastomeric hollow interior was made as in Example 6. However, the outer cover was made from felt having a 40% wool 60% nylon by weight composition. The range of felt compositions extends from 20% wool 80% nylon to 80% wool 20% nylon by weight.

It has been determined that the balls of the abovementioned examples are able to stand repeated use to at least approach the use periods of conventional balls. Accordingly, the economic cost of such balls is not prohibitive.

The foregoing describes only some embodiments of the present invention and modifications, obvious to those skilled in the art, can be made thereto without departing from the scope of the present invention.

Claims

1. A phosphorescent ball for night time sporting and leisure activities, said ball comprising plastics to which during manufacture a phosphorescent pigment has been added.

2. A ball as claimed in claim 1 wherein said plastics is

transparent and the pigment is added to the plastics by incorporation within said transparent plastics.

3. A ball as claimed in claim 2 having an inner core and an outer covering, said outer covering comprising said plastics.

4. A ball as claimed in claim 3 wherein said inner core is reflective.

5. A ball as claimed in claim 4 wherein said inner core is white.

6. A ball as claimed in claim 3 wherein said outer covering comprises an ionomer.

7. A ball as claimed in claim 6 wherein said outer covering is provided with at least one exterior clear coating.

8. A ball as claimed in claim 8 wherein a phosphorescent pigment is added to said exterior clear coating.

9. A ball as claimed in claim 2 or 8 wherein said pigment is added at a concentration of 10% to 50% by weight.

10. A ball as claimed in claim 1 having an inner, hollow

elastomeric core and a fibrous outer cover, said plastics being in the form of fibresincorporated in said fibrous outer cover.

11. A ball as claimed in claim 1 wherein said pigment is added to said fibres by dyeing.

12. A ball as claimed in claim 10 wherein said fibrous outer cover comprises a felt blend of wool and nylon.

13. A ball as claimed in claim 12 wherein said fibrous outer cover is in the range of 20% wool and 80% nylon to 80% wool 20% nylon by weight.

14. A ball as claimed in claim 1 wherein said phosphorescent pigment is a crystalline powder.

15. A ball as claimed in claim 14 wherein said powder is ZnS:Cu.

16. A method of manufacturing a ball as claimed in claim 1, said method comprising the step of simultaneously and separately feeding said pigment and said plastics into an injection moulding machine.

17. A method as claimed in claim 11 wherein said pigment is a crystalline powder.

18. A method as claimed in claim 17 wherein said powder is ZnS:Cu.