Golf Ball Core Hardness Gradient via Water-Releasing Agent
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional golf ball cores with thermoset rubber materials exhibit variability in hardness gradients, leading to inconsistent spin rates and durability, particularly in recreational players who struggle with high spin balls.
Innovation Solution
Incorporating a water-releasing agent, such as a metal sulfate hydrate, into the core rubber formulation during curing to create a positive hardness gradient, where the outer surface is harder than the center, reducing spin rates while maintaining impact durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional thermoset rubber core is used with standard curing cycle, then the core achieves basic structural integrity, but the hardness gradient is insufficient (5-30 Shore C) leading to high spin rates that recreational players cannot control
Solution Approach 1:
The patent applies local quality by creating distinct hardness zones within the core through spatially varying crosslinking density. The center region has lower crosslinking density (softer) while the outer region has higher crosslinking density (harder), achieving a hardness gradient of 30-50 Shore C. This localized property variation allows the core to provide both spin control and durability, resolving the contradiction between ease of operation and manufacturing precision.
Solution Approach 2:
The patent changes the crosslinking parameter by using a water-releasing agent that generates water in situ during curing. This water participates in the crosslinking reaction, and by controlling the amount and distribution of water-releasing agent, the patent achieves different crosslinking densities at different locations within the core, thereby creating the desired hardness gradient without requiring complex multi-step curing processes.
2Ease of operation
If the core hardness is increased to reduce spin rate, then spin control improves, but impact durability decreases
Solution Approach 1:
The patent resolves this contradiction by applying different hardness properties to different locations within the core. The outer core layer has higher hardness (80-100 Shore C) to reduce spin rate and improve control, while the center has lower hardness (45-65 Shore C) to maintain impact durability and energy absorption. This spatial differentiation allows both spin control and durability requirements to be satisfied simultaneously.
Solution Approach 2:
The patent creates a composite core structure with an outer core layer and an inner core layer, each having different crosslinking densities and hardness properties. This composite construction allows the outer layer to provide spin control while the inner layer provides impact durability, resolving the contradiction between these two performance requirements.
3Strength
If a harder core is used to maintain durability, then impact resistance improves, but spin rate increases making the ball difficult to control
Solution Approach 1:
The patent applies local quality by creating a hardness gradient where the outer core layer (in contact with the club) has higher hardness for spin control, while the inner core has lower hardness for durability. This localized property assignment allows the core to simultaneously provide both spin control and impact durability, resolving the contradiction between these two requirements.
4Ease of operation
If a steeper hardness gradient is implemented to reduce spin rate, then spin control improves, but manufacturing complexity increases
Solution Approach 1:
The patent changes the chemical parameter by introducing a water-releasing agent that simplifies the curing process. Instead of using complex multi-step curing cycles or multi-layer molding processes to achieve a steep hardness gradient (30-50 Shore C), the patent uses a single-step curing process where the water-releasing agent generates water in situ that participates in crosslinking, naturally creating the desired gradient through diffusion and reaction kinetics. This reduces manufacturing complexity while achieving the target spin control performance.
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 increased hardness gradient reduces spin rates, enhancing control and distance for recreational players by promoting radical deactivation and crosslinking density differences between the core's surface and center, resulting in improved ball velocity and launch angles.
Implementation Method 1
a water releasing agent including a metal sulfate hydrate having one to four waters of hydration
Implementation Method 2
an organic peroxide, a cross-linking co-agent including a zinc salt of an acrylate, diacrylate, methacrylate, or dimethacrylate
Data Source
AI summary
Golf balls having cores with increased hardness gradients are provided. The cores have an increased “positive” hardness gradient (or a “hard-to-soft” hardness) where the outer surface of the core is harder than the center. The increased positive hardness gradient can be achieved by introducing a water-releasing agent into the core rubber formulation during the curing process. The resulting golf balls have reduced spin and sufficient impact durability.