Most properties of the golf ball, such as speed, spin, and durability depend on the performance of its core. We define a golf ball core as having the composition of an elastomeric polymer, or more specifically polybutadiene rubber, because it is known to have the best compression-to-resilience ratio of any golf ball material. Callaway is one of only a few major golf ball companies that employs a dual core technology to produce better speed and spin control than a solid one-piece core design.
It’s generally understood that most golfers prefer a golf ball that has lower driver spin and a higher green side spin. In a dual core construction, this is typically achieved by designing a larger/softer inner core and a thinner/firmer outer core. However, a thin outer core layer, combined with a high compression differential between the inner and outer cores, puts extreme stress on the outer core at impact, sometimes beyond the threshold of durability.
As a result, we’ve been constrained on how far we can expand dual core technology, and have had to place limits on inner core compression and size. All of this changed back in 2016 when our R&D team started working with a novel material called graphene, never before used in golf balls, that could enhance the durability of dual core and unlock design space that we never before would have considered.
Rendering of a Graphene || Extremetech.com
Graphene was recently discovered only 13 years ago by British scientists Konstantin Novoselov and Andre Geim, and their work with graphene led them to win the Nobel Prize in Physics in 2010. Pure graphene is comprised of carbon atoms in 2-dimensional hexagonal arrangement that’s only 1 atom thick! It’s the same foundational carbon material that is the building block in both diamond and graphite, similar to that found in lead pencils.
It’s extremely strong, light weight, stiff, and yet elastic so you stretch it beyond its original length without breaking. Scientific experts in the field of materials and composites claim graphene to be the strongest material ever discovered by man. To give a hypothetical example of graphene’s strength a 1 m2 hammock made entirely of graphene can hold a cat weighing up to 4 kg without breaking. This hammock would weigh less than 1 mg, equivalent to weight of its whisker.
To understand its light weight, if you hypothetically spread a single layer of graphene across an entire football field, it would weigh less than 1 gram! And in terms of elasticity, in spite of being 200 times stronger than steel, graphene has the ability to elongate 20% more than its original size.
Rubber slugs before they’re pressed into cores
Because of its ultra-high strength, very small amounts are needed to achieve desired benefits in mechanical properties of composites. Even though graphene started as a very expensive material after it was originally isolated by the scientists, the latest innovation in its production engineering has brought down the cost to more reasonable levels. As a result, many types of sports equipment have recently been modified with graphene and available to consumers, such as tennis racquets, bike helmets, skis, and hockey sticks.
When we initially explored it in golf ball core recipe, we were astonished to find a durability improvement of more than 200%! It took months of development to figure out how to homogeneously disperse such a fine nano-material into our rubber core mixture, but we finally achieved success and the result was an incredible strength improvement in the outer core of our Chrome Soft products. The high strength reinforcement capability of graphene in our core mixture has opened up a completely new design space for our dual core golf balls. We now can design a much larger softer inner core and cover it with a thinner, stronger outer core to achieve the ball performance we want.
Close up: Chrome Soft Dual Soft Fast Core with graphene
Graphene incorporated in the outer core, as shown in Figure 1, improves the overall ability of the dual core to withstand high velocity club impact. By enabling us to make the inner core larger and softer, this new graphene based core design reduces driver spin while increasing launch angle, the key to longer distance. In addition, by being able to lower spin on full shots, it enables us to put an even softer urethane cover on the ball to increase green side spin.
To describe this in golfing terms, Figure 2 below shows the spin profile for our new 2018 Chrome Soft with graphene-infused dual core.
Figure 2. Comparison of new 2018 Chrome Soft
To create the spin profile chart our robot setup conditions ranged from a high speed driver condition (on the left) to a short wedge shot condition (on the right). The plotted lines compare the spin of our new Chrome Soft and the original Chrome Soft to the leading competitor. As seen in this graph, Chrome Soft demonstrates much lower spin on full shots, but within 100 yards the spin increases dramatically where golfers want and need it the most. This benefit is made possible by our graphene technology.
The new Chrome Soft and Chrome Soft X golf balls are the first ever to experience the benefits of graphene in a dual core construction. The strength of graphene, and its ability to reinforce the outer core layer, allow us to design golf balls in a unique way. These two balls are unlike anything on the market!
About the Author:
Vijay holds a PhD in polymer science from the University of Akron. He developed novel functional rubber and plastic materials during his PhD at Akron. After graduating, he worked in coating industries for 4.5 years. He has been working in golf ball industry since Jan 2016.