Golf Ball Rubber Composition Optimizing Shot Feeling

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Solution Overview

Problem

Existing golf ball rubber compositions fail to provide excellent shot feeling on both driver shots and approach shots, as they lack the necessary balance of resilience and hardness to enhance performance across different swing speeds.

Innovation Solution

A golf ball rubber composition that includes a base rubber, an α,β-unsaturated carboxylic acid or its metal salt as a co-crosslinking agent, a crosslinking initiator, and a hindered phenol-based compound, with a specific formulation that achieves a product index of (hardness × (tanδ -80 - tanδ 0 ) of 28.0 or more, ensuring improved shot feeling on both driver and approach shots.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a rubber composition containing base rubber, co-crosslinking agent and crosslinking initiator is used to form the golf ball core, then good resilience is achieved, but excellent shot feeling on both driver shots and approach shots cannot be provided

Engineering Contradiction:
ImproveresilienceVSAvoidshot feeling performance
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent introduces a specific parameter (product of hardness and loss tangent difference) to quantify and control the shot feeling performance. By setting this parameter to 28.0 or more, the patent optimizes the balance between resilience and hardness to achieve excellent shot feeling on both driver shots and approach shots, resolving the contradiction between good resilience and versatile shot feeling performance.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite rubber composition containing base rubber, co-crosslinking agent, crosslinking initiator, and hindered phenol-based compound. This composite material structure allows the golf ball core to simultaneously achieve good resilience from the rubber composition and excellent shot feeling on both driver and approach shots through the specific formulation and the hindered phenol-based compound.

Inventive Principle:
Principle #40Composite materials

2Ease of operation

If the golf ball core is made softer to improve shot feeling on approach shots, then driver shot performance deteriorates

Engineering Contradiction:
Improveshot feeling on approach shotsVSAvoiddriver shot performance
Core Design Contradiction:
Ease of operationVSSpeed

Solution Approach 1:

The patent uses the product parameter (hardness × loss tangent difference) to precisely control the core's mechanical properties. By optimizing this parameter to 28.0 or more, the patent achieves a balance where the core provides excellent shot feeling on approach shots while maintaining sufficient hardness and resilience for driver shot performance, avoiding the need to make the core softer.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent utilizes the temperature-dependent loss tangent characteristics of the rubber composition to create dynamic performance. The loss tangent difference between -80°C and 0°C reflects the material's dynamic response to different impact conditions, allowing the core to adapt its behavior based on the type of shot (driver vs. approach) without requiring different hardness levels.

Inventive Principle:
Principle #15Dynamics

3Speed

If the golf ball core is made harder to improve driver shot performance, then shot feeling on approach shots becomes excessively hard

Engineering Contradiction:
Improvedriver shot performanceVSAvoidshot feeling on approach shots
Core Design Contradiction:
SpeedVSEase of operation

Solution Approach 1:

The patent introduces a specific parameter (product of hardness and loss tangent difference ≥ 28.0) that simultaneously accounts for both hardness and energy dissipation characteristics. This parameter optimization allows the core to maintain sufficient hardness for driver shot performance while ensuring the shot feeling on approach shots is not excessively hard, as the loss tangent component controls the material's cushioning effect.

Inventive Principle:
Principle #35Parameter changes

4Ease of operation

If the loss tangent difference (tanδ -80 - tanδ 0) is increased to improve shot feeling, then the product index becomes excessively high

Engineering Contradiction:
Improveshot feelingVSAvoidproduct index control
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent sets a specific threshold (product ≥ 28.0) for the product of hardness and loss tangent difference to ensure excellent shot feeling on both driver and approach shots. This parameter control provides clear manufacturing guidance while avoiding excessively high values that would indicate over-optimization. The hindered phenol-based compound helps achieve this parameter range through its specific formulation effects.

Inventive Principle:
Principle #35Parameter changes

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 composition provides a golf ball with enhanced shot feeling on both driver shots and approach shots by optimizing the balance of resilience and hardness, maintaining resilience while ensuring the shot feeling is not excessively soft or hard, thus improving overall performance.

Implementation Method 1

a rubber composition containing a base rubber, a co-crosslinking agent and a crosslinking initiator

Methodology Applied
Scientific EffectCrosslinking: Chemical Bonding

Implementation Method 2

a vulcanized molded product of a rubber composition

Methodology Applied
Scientific EffectVulcanization: Chemical Bonding

Implementation Method 3

the golf ball rubber composition further contains (d) a hindered phenol-based compound

Methodology Applied
Scientific EffectAntioxidation: Oxidation

Implementation Method 4

a loss tangent of the cured product of the golf ball rubber composition at the temperature of -80 °C (tanδ -80 ) and a loss tangent of the cured product of the golf ball rubber composition at the temperature of 0 °C (tanδ 0)

Methodology Applied
Scientific EffectViscoelasticity: Viscoelasticity

Data Source

PatentEP3875529B1Cured product of golf ball rubber composition and golf ball
Publication Date: 2023.04.26 SUMITOMO RUBBER INDUSTRIES LTD
  • EP3875529B1 patent drawingFigure 1
  • EP3875529B1 patent drawingFigure 2
  • EP3875529B1 patent drawing

AI summary

An object of the present invention is to provide a cured product of a golf ball rubber composition for constituting a golf ball having excellent shot feeling on both driver shots and approach shots. The present invention provides a cured product of a golf ball rubber composition, wherein the golf ball rubber composition contains (a) a base rubber, (b) an α,β-unsaturated carboxylic acid having 3 to 8 carbon atoms and/or a metal salt thereof as a co-crosslinking agent, and (c) a crosslinking initiator, and a product (hardness x (tanδ-80 - tanδ0)) obtained by multiplying a slab hardness of the cured product of the golf ball rubber composition in Shore C hardness by a difference (tanδ-80- tanδ0) between a loss tangent of the cured product of the golf ball rubber composition at -80 °C (tanδ-80) and a loss tangent of the cured product of the golf ball rubber composition at 0 °C (tanδ0) is 28.0 or more.