Heavy filler in golf ball cores

#1. Field of the Invention

#The invention relates generally to compositions for golf balls. More specifically, the invention relates to fillers for golf ball centers and cores.

#2. Description of the Related Art

#FIG. 1 is a cross section of a three-piece golf ball according to one embodiment of the invention.

#FIG. 2 is a cross section of a two-piece golf ball according to one embodiment of the invention.

#As is well known in the art, fillers can be incorporated into golf ball cores and centers to increase the weight of the resulting golf ball. It has now been discovered that the utilization of high density fillers having specific gravities of about 5.4 or greater can be used to increase the weight of a golf ball center 1 (as shown in FIG. 1), or core 1a (as shown in FIG. 2) without significantly reducing the rebound characteristics of the resulting golf ball which further comprises cover 2.

#The following table contains a list of high density inorganic elements that meet the aforementioned criteria. The list is provided by way of illustration and not limitation. The key criteria is that the filler material must have a specific gravity of at least about 5.6. 1 TABLE 1 Inorganic Element Specific Gravity Tungsten 19.3 Bismuth 9.8 Copper 8.9 Bismuth oxide 8.9 Nickel 8.9 Cobalt 8.9 Iron/Steel 7.7 Tin 7.3 Chromium 7.2 Zinc 7.1 Bismuth subcarbonate 6.9 Cupric oxide 6.4 Barium tungstate 6.4 Cuprous oxide 6.0 Ferrous oxide 5.7

#In one embodiment, centers or cores incorporating such fillers are prepared by dry mixing polybutadiene rubber with the filler of choice and other rubber vulcanizing ingredients to create the desired blend. Mixing can be accomplished in an internal mixer such as a Banbury mixer or an open mill as is well known in the art. The mixture is then sheeted and allowed to cool for preferably 8 hours minimum.