Golf Ball Core Crosslink Density Control

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Solution Overview

Problem

Existing golf balls fail to maintain a good rebound and durability while reducing spin rate and increasing distance, as they experience energy loss and resilience decrease over time.

Innovation Solution

A golf ball core formed from a rubber composition including base rubber, organic peroxide, and water/metal monocarboxylate, with controlled crosslink density and dynamic viscoelastic properties, promotes radical decomposition and crosslinking differences between the core surface and center, maintaining rebound and reducing spin.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional rubber compositions are used in the golf ball core, then the core can be manufactured, but the golf ball experiences energy loss and resilience decrease over time, failing to maintain good rebound and durability

Engineering Contradiction:
ImprovedurabilityVSAvoidenergy loss
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent changes the chemical composition parameters of the rubber core by incorporating specific antioxidants (such as hindered phenol antioxidants and phosphite antioxidants) and process control parameters (vulcanization temperature and time) to prevent oxidation and maintain resilience over time, thereby reducing energy loss while improving durability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite rubber materials combining base rubber with specific additives including antioxidants, peroxides, and other compounds in controlled amounts to create a core material that resists degradation and maintains its elastic properties, reducing energy loss while enhancing durability

Inventive Principle:
Principle #40Composite materials

2Speed

If the core material is designed to reduce spin rate and increase distance, then golf ball performance is improved, but the material cannot reliably maintain resilience and experience little energy loss over time

Engineering Contradiction:
ImprovedistanceVSAvoidresilience maintenance
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The patent optimizes physical parameters including crosslink density (controlled through peroxide content and vulcanization conditions), hardness gradient, and elastic modulus to achieve the desired spin rate reduction and distance improvement while ensuring the core maintains its resilient properties over extended use

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a core with non-uniform properties, specifically a hardness gradient where the center and surface have different hardness values, and varies the crosslink density distribution to optimize both the spin rate reduction for distance and the resilience maintenance for reliability

Inventive Principle:
Principle #3Local quality

3Stability of the object's composition

If crosslink density is increased to improve core stability and reduce spin, then the core becomes more stable, but the manufacturing precision of crosslink density distribution between surface and center becomes difficult to control

Engineering Contradiction:
Improvecore stabilityVSAvoidcrosslink density distribution control
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The patent incorporates peroxides and other crosslinking agents into the rubber composition before vulcanization, and pre-establishes the formulation ratios and processing parameters to ensure controlled crosslink density distribution between the core surface and center during the vulcanization process

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent establishes specific ranges for crosslink density values and their distribution patterns based on empirical data and testing, using these feedback results to refine the formulation and processing parameters to achieve the desired crosslink density distribution that balances core stability with manufacturing precision

Inventive Principle:
Principle #23Feedback

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 golf ball achieves a reduced spin rate, excellent durability, and minimal change in rebound over time, enhancing distance and maintaining performance.

Implementation Method 1

an organic peroxide... decomposition of the organic peroxide within the core formulation can be promoted

Methodology Applied
Scientific EffectDecomposition: Decomposition (biological)

Implementation Method 2

the product P×E of the difference P (mol/m3) in crosslink density between a surface of the core and a center of the core

Methodology Applied
Scientific EffectCrosslinking: Chemical Bonding

Implementation Method 3

water and/or a metal monocarboxylate... decomposition of the organic peroxide within the core formulation can be promoted by directly blending water

Methodology Applied
Scientific EffectHydrolysis: Hydrolysis

Implementation Method 4

in a dynamic viscoelasticity test on the hot-molded material containing components (A) to (C), when the loss tangent of the core center is measured

Methodology Applied
Scientific EffectViscoelasticity: Viscoelasticity

Implementation Method 5

a core material which undergoes little decrease in resilience over time and little energy loss

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentUS10124215B2Golf ball
Publication Date: 2018.11.13 BRIDGESTONE SPORTS CO LTD

AI summary

The invention provides a golf ball having a core and a cover of one layer or a plurality of layers, the core being formed of a material molded under heat from a rubber composition which includes (A) a base rubber, (B) an organic peroxide, and (C) water and/or a metal monocarboxylate. The product P×E of the difference P (mol/m3) in crosslink density between the core surface and the core center, as measured based on a toluene swelling test, multiplied by the deflection E (mm) of the core when compressed under a final load of 1,275 N (130 kgf) from an initial load state of 98 N (10 kgf) is at least 28×102 mol/m3·mm.