Golf Ball Cover Resin Composition for Rebound and Scuff Resistance

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Solution Overview

Problem

Golf balls using ethylene/acid copolymers or metal salts as cover materials face issues with durability to repeated impact and scuff resistance, with existing modifications failing to improve desired properties like distance, spin rate, and rebound resilience.

Innovation Solution

A resin composition combining an acid-containing copolymer with a specific acid content and an amine-containing polymer, such as polyethyleneimine, which enhances compatibility and dynamic viscoelasticity, resulting in improved rebound resilience and scuff resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If ethylene/acid copolymers or metal salts are used as cover material, then rebound resilience is improved, but durability to repeated impact and scuff resistance worsen

Engineering Contradiction:
Improverebound resilienceVSAvoiddurability to repeated impact
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent uses a composite material system consisting of ethylene/acid copolymer blended with specific elastomers (polyester elastomer, styrene elastomer, polyamide elastomer, or polyurethane elastomer) to create a cover material that simultaneously achieves high rebound resilience and durability. The composite formulation allows the elastomer components to enhance toughness and impact resistance while the ethylene/acid copolymer maintains the rebound properties.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent optimizes specific parameters including the acid content of the ethylene/acid copolymer (5-30 mass%), the type and amount of elastomer additive (1-50 mass%), and the degree of neutralization to achieve the desired balance between rebound resilience and durability. By precisely controlling these compositional parameters, the material exhibits both high elasticity for rebound and enhanced toughness for impact resistance.

Inventive Principle:
Principle #35Parameter changes

2Strength

If acid content in ethylene/acid copolymer increases, then rigidity is improved, but scuff resistance worsens

Engineering Contradiction:
ImproverigidityVSAvoidscuff resistance
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent optimizes the acid content parameter within a specific range (5-30 mass%) to achieve the desired balance between rigidity and scuff resistance. Additionally, the degree of neutralization with metal ions is controlled (50-150 mass% relative to acid content) to further fine-tune the material properties, allowing the cover to maintain sufficient rigidity for structural integrity while improving scuff resistance through enhanced toughness from the composite formulation.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent incorporates elastomers into the ethylene/acid copolymer matrix to create a composite material that maintains rigidity from the copolymer structure while the elastomer phase provides scuff resistance through its toughness and ability to absorb surface-level damage without permanent deformation.

Inventive Principle:
Principle #40Composite materials

3Duration of action of stationary object

If elastomer is blended to improve toughness, then durability is improved, but rebound resilience deteriorates

Engineering Contradiction:
ImprovedurabilityVSAvoidrebound resilience
Core Design Contradiction:
Duration of action of stationary objectVSReliability

Solution Approach 1:

The patent precisely controls the elastomer content within 1-50 mass% of the total cover material composition and selects specific types of elastomers with appropriate glass transition temperatures and molecular structures. This parameter optimization ensures that the elastomer provides sufficient toughness and durability enhancement while maintaining the overall elastic recovery properties necessary for high rebound resilience.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite material where different phases serve different functions: the ethylene/acid copolymer matrix provides the primary elastic recovery and rebound properties, while the dispersed elastomer phase provides localized toughness and impact absorption. This local differentiation of material quality allows simultaneous achievement of durability and rebound resilience.

Inventive Principle:
Principle #3Local quality

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 resin composition provides golf balls with excellent rebound resilience, durability to cracking, and scuff resistance, making it suitable for use as a cover material in golf balls.

Implementation Method 1

because some of the acid constituent in the acid-containing copolymer covalently bonds with the amine in the amine-containing polymer

Methodology Applied
Scientific EffectCovalent bonding: Chemical Bonding

Data Source

PatentUS11608434B2Resin composition for golf ball, and golf ball
Publication Date: 2023.03.21 BRIDGESTONE SPORTS CO LTD

AI summary

A resin composition for golf balls includes (a) an acid-containing copolymer having an amount of acid constituent per 100 wt % of the sum of monomer units in the copolymer that is from 1 to 30 wt %, and (b) an amine-containing polymer having a branched structure. The resin composition imparts golf balls with an excellent rebound resilience and also confers an outstanding durability to repeated impact and an outstanding scuff resistance, making it particularly useful as a cover material in golf balls.