Highly Neutralized Acid Polymer Golf Ball Compositions

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Solution Overview

Problem

Conventional highly neutralized ionomers used in golf ball layers are hydrophilic, leading to moisture absorption issues during processing and reduced performance due to plasticization by water molecules, resulting in voids and decreased coefficient of restitution and stiffness.

Innovation Solution

Development of moisture-resistant compositions using highly neutralized acid polymers with at least 70% neutralization, achieved by contacting acid polymers with lithium or zinc-based cation sources and a melt flow modifier, which improves moisture vapor transmission rates while maintaining durability and desirable melt flow properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional highly neutralized ionomers are used in golf ball layers, then resilience and durability are improved, but moisture absorption increases leading to processing difficulties and performance reduction

Engineering Contradiction:
Improveresilience and durabilityVSAvoidmoisture absorption
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical composition parameters of the ionomer by using alternative cation sources (calcium, strontium, barium, aluminum, or mixtures thereof) instead of traditional sodium or potassium cations. This parameter change fundamentally alters the hydrophilic nature of the ionomer, reducing moisture absorption from 2,000-10,000 ppm to significantly lower levels while preserving the desired resilience and durability properties for golf ball applications.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite ionomer material by combining polymer chains with specifically selected cation sources and controlling the distribution of ionic aggregates. This composite approach allows the material to achieve both high resilience/durability through ionic bonding and low moisture absorption through strategic cation selection, effectively resolving the contradiction between these two properties.

Inventive Principle:
Principle #40Composite materials

2Ease of manufacture

If conventional highly neutralized ionomers are used, then processing is simplified, but voids are created during injection molding due to moisture

Engineering Contradiction:
Improveprocessing simplicityVSAvoidvoid formation during molding
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

By changing the cation composition parameters to use less hygroscopic cations (calcium, strontium, barium, aluminum), the patent fundamentally alters the moisture interaction characteristics of the ionomer. This parameter change eliminates the void formation issue during injection molding while maintaining ease of processing, as the material remains thermoplastically processable without the harmful moisture-related defects.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If conventional highly neutralized ionomers are used, then golf ball performance is improved, but coefficient of restitution and stiffness decrease due to plasticization by water

Engineering Contradiction:
Improvegolf ball performanceVSAvoidcoefficient of restitution and stiffness
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent changes the chemical parameters of the ionomer by selecting cation sources that do not promote water absorption. This parameter change prevents the plasticization effect that would otherwise degrade the coefficient of restitution and stiffness, thereby maintaining high golf ball performance without the strength degradation caused by moisture uptake in conventional ionomers.

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 solution provides golf balls with improved moisture resistance, maintaining desirable performance characteristics such as coefficient of restitution and melt flow, while reducing moisture absorption, thus enhancing processing and performance stability.

Implementation Method 1

contacting one or more acid polymers with a sufficient amount of a lithium-based cation source, in the presence of a melt flow modifier, to increase the level of neutralization of the acid polymer to 70% or higher

Methodology Applied
Scientific EffectNeutralization reaction: Redox Reactions

Implementation Method 2

contacting one or more acid polymers with a sufficient amount of a lithium-based cation source, in the presence of a melt flow modifier, to increase the level of neutralization

Methodology Applied
Scientific EffectRheological modification:

Implementation Method 3

conventional highly neutralized ionomers are hydrophilic, due to the highly hydrophilic nature of the cation sources traditionally used to neutralize the ionomers

Methodology Applied
Scientific EffectHydrophobicity: Hydrophobe

Data Source

PatentUS7452289B2Highly neutralized acid polymer compositions having a low moisture vapor transmission rate and their use in golf balls
Publication Date: 2008.11.18 ACUSHNET CO

AI summary

The present invention is directed to a golf ball having at least one layer formed from a moisture resistant, highly neutralized acid polymer composition. Highly neutralized acid polymers of the present invention are produced with a cation source selected from ions and compounds of lithium, ions and compounds of zinc, and combinations thereof. Golf balls of the present invention include one-piece, two-piece, multi-layer, and wound golf balls. The composition may be present in any one or more of a core layer, a cover layer, or an intermediate layer.