Multi-layer core golf ball with hardness gradient
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Solution Overview
Problem
There is a need for a golf ball with a very high positive gradient core that includes a very soft, low compression inner core layer formed from an unfoamed composition, which provides good durability while reducing spin, particularly for use with drivers while maintaining moderate spin with wedges and irons.
Innovation Solution
A golf ball design featuring a core with a solid inner core layer made from peroxide-cured polybutadiene rubber and an outer core layer composed of a thermoplastic composition, where the inner core layer has a center Shore C hardness of 50 or less and the outer core layer has a Shore C hardness of 70 or greater, creating a significant hardness gradient to achieve the desired spin profile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a soft inner core layer is used to reduce spin off driver, then spin reduction is achieved, but durability may be compromised
Solution Approach 1:
The core is divided into multiple layers with different hardness properties: a soft inner core layer (Shore C 30-50) for spin reduction and a harder outer core layer (Shore C 50-70) for durability. This segmentation allows each layer to perform its specific function optimally without compromising the other.
Solution Approach 2:
The golf ball core uses composite material construction with at least two different rubber compositions having different Shore C hardness values. The inner layer uses a softer composition while the outer layer uses a harder composition, creating a composite structure that simultaneously achieves spin control and durability.
2Object-generated harmful factors
If a high positive hardness gradient core is used to reduce spin, then spin profile is improved, but manufacturing complexity increases
Solution Approach 1:
The core is segmented into distinct layers with progressively increasing hardness from inner to outer layers, creating a controlled positive hardness gradient. This segmentation simplifies the manufacturing process compared to creating a continuous gradient, while still achieving the desired spin profile through the stepped hardness progression.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design results in a golf ball that produces reduced spin off the driver while maintaining moderate spin off wedges and irons, enhancing durability and performance by utilizing a high positive hardness gradient core.
Implementation Method 1
The inner core layer consists of a peroxide cured polybutadiene rubber composition
Data Source
AI summary
Golf ball incorporating core consisting of: a solid inner core layer consisting of a peroxide cured polybutadiene rubber composition and having a diameter of 1.25 inches or less and a center Shore C hardness (Hcenter) of 50 or less; and an outer core layer consisting of a thermoplastic composition Tc as defined herein and having a thickness of 0.400 inches or greater and an outer surface Shore C hardness (Houter surface) of 70 or greater, wherein Houter surface>Hcenter, and Houter surface−Hcenter≧40. The peroxide cured polybutadiene rubber composition may comprise a reaction product of polybutadiene and a sufficient amount of peroxide to form the solid inner layer having the center Shore C hardness (Hcenter) of 50 or less. In one embodiment, 100 phr polybutadiene and from about 0.05 phr to about 3.0 phr of peroxide are mixed with at least one of 5 phr or less of a metal oxide; 5 phr or less of a metal coagent; or 5 phr or less of a metal carbonate. Alternatively, the solid inner core layer has a diameter of 1.10 inches or less or less than 1.0 inches.