Golf Ball Core Hardness Gradient and Spin Reduction
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Solution Overview
Problem
Golf balls with increased core hardness gradients for reduced spin rates often suffer from poor durability due to contaminant incorporation during production, limiting the extent to which spin rates can be lowered.
Innovation Solution
A golf ball core composition with a base rubber, α,β-unsaturated carboxylic acid or metal salt, organic peroxide, and water, where the molar ratio of the co-crosslinking agent to active oxygens in the organic peroxide is increased, creating a highly grafted and low-crosslinked rubber structure that enhances durability and maintains low spin characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the hardness gradient at the core interior is increased to reduce spin rate, then the spin characteristics are improved, but the durability to impact deteriorates due to premature core failure
Solution Approach 1:
The invention changes the chemical composition parameters of the rubber composition by controlling the molar ratio E of co-crosslinking agent to active oxygens to be 70 or more, and adjusting water content to 0.1-10 parts by weight per 100 parts of base rubber. This parameter optimization creates a hardness gradient of 16 or more between core surface and center while preventing premature failure, resolving the contradiction between spin reduction and impact durability.
Solution Approach 2:
The invention uses a composite rubber composition system combining base rubber with specific amounts of co-crosslinking agent (α,β-unsaturated carboxylic acid or metal salt), organic peroxide, and water. This composite material approach creates a multi-functional core structure that simultaneously achieves low spin characteristics and high impact durability by leveraging the synergistic effects of different components.
2Productivity
If the hardness gradient at the core interior is increased to reduce spin rate, then the flight performance is improved, but the core becomes susceptible to contaminant-induced premature failure
Solution Approach 1:
The invention optimizes the chemical parameters of the rubber composition, specifically setting the molar ratio E of co-crosslinking agent to active oxygens at 70 or more and water content at 0.1-10 parts by weight per 100 parts of base rubber. These parameter changes create a resilient core structure with hardness gradient of 16 or more that resists contaminant-induced failure while maintaining flight performance.
Solution Approach 2:
The invention incorporates water and co-crosslinking agent in specific amounts beforehand to create a protective rubber matrix that cushions against the harmful effects of contaminants. This prior preparation prevents premature core failure by creating a more resilient and less susceptible structure before the core is subjected to impact forces during play.
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 solution achieves a large hardness difference in the core interior, reducing spin rates while preventing premature failure and improving impact durability, even when contaminants are present.
Implementation Method 1
by making the compounding ratio (molar ratio) between component (b) and component (c) larger than in the prior art, specifically, by preparing the rubber composition such that E, defined by the formula E=molar amount of component (b)/molar amount of active oxygens in component (c), has a value of 70 or more
Implementation Method 2
creating a highly grafted and low-crosslinked rubber structure that enhances durability and maintains low spin characteristics
Data Source
AI summary
In a golf ball having a core and a cover of one or more layer, the core is a product molded under heat from a rubber composition which includes (a) a base rubber, (b) a co-crosslinking agent which is an α,β-unsaturated carboxylic acid and/or a metal salt thereof, (c) an organic peroxide, and (d) water, wherein the content of component (d) is set within a specific range and components (b) and (c) are included in relative amounts that satisfy a specific condition. The core has a specific compressive deformation and a specific hardness difference between the center and surface thereof. Owing to the large hardness difference in the internal hardness profile of the core, the ball exhibits low spin characteristics when hit, improving the flight performance, yet retains a good durability to impact.