Patent attributes
A golf club head with at least one cavity including a fill material comprising a polymer and a plurality of microscopic bubbles, and methods of manufacturing such golf club heads, are disclosed herein. In particular, the golf club head comprises an internal cavity that is at least partially filled with the fill material, or a medallion comprising the microscopic bubble fill material. The plurality of microscopic bubbles constitutes at 5-70% of the volume of the fill material, and more preferably approximately 20-30% of the volume of the fill material. The polymer material preferably is a polyurethane having a Poisson's ratio of 0.40-0.50. In some embodiments, the fill material takes the form a medallion affixed to a rear surface of the striking face, while in others, the fill material is injected into the internal cavity.
