Multi-Piece Golf Ball Bonding Layer for Urethane Cover Adhesion

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Solution Overview

Problem

Multi-piece solid golf balls with soft urethane covers face challenges in maintaining durability and spin performance, particularly when the cover is thinly designed, due to insufficient adhesion between the intermediate and cover layers.

Innovation Solution

A multi-piece solid golf ball design featuring a core, intermediate layer, and outer layer, where the intermediate layer is made from a specific acid-containing polymer or ionomer resin, and the outer layer is primarily polyurethane or polyurea, with a bonding layer of polycarbodiimide-containing polycarbonate and/or polyether-type aqueous polyurethane dispersion composition, enhancing adhesion and durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a soft urethane cover is designed to be thin, then spin performance on approach shots is improved, but durability on repeated impact deteriorates

Engineering Contradiction:
Improvespin performanceVSAvoiddurability
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent employs composite materials by combining a soft urethane outer layer with an ionomer resin intermediate layer and a polycarbodiimide-containing bonding layer. This multi-material construction allows the outer layer to maintain softness for spin performance while the intermediate layer and bonding layer provide structural support and adhesion for durability.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent introduces an intermediate layer made of ionomer resin and a bonding layer containing polycarbodiimide as intermediary elements between the core and the soft urethane cover. These intermediary layers enhance adhesion and distribute impact stresses, preventing delamination and improving durability without compromising the softness or spin characteristics of the outer cover.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a soft urethane cover is designed to be thin, then spin performance on approach shots is improved, but adhesion between layers deteriorates

Engineering Contradiction:
Improvespin performanceVSAvoidadhesion between layers
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent introduces an intermediate layer made of ionomer resin and a bonding layer containing polycarbodiimide as intermediary elements between the core and the soft urethane cover. These intermediary layers enhance adhesion and distribute impact stresses, preventing delamination and improving durability without compromising the softness or spin characteristics of the outer cover.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent utilizes parameter changes by selecting specific resin compositions with appropriate molecular weights, crosslinking densities, and chemical functional groups. The ionomer resin and polycarbodiimide-containing resin are chosen to optimize adhesion parameters, creating strong interfacial bonding that maintains layer stability even when the outer cover is thin.

Inventive Principle:
Principle #35Parameter changes

3Stability of the object's composition

If water-dispersible polycarbodiimides are used with aqueous polyurethanes, then compatibility between adhesive and cover material is improved, but affinity with ionomer resin base resin deteriorates

Engineering Contradiction:
ImprovecompatibilityVSAvoidadhesion
Core Design Contradiction:
Stability of the object's compositionVSStrength

Solution Approach 1:

The patent utilizes parameter changes by selecting specific resin compositions with appropriate molecular weights, crosslinking densities, and chemical functional groups. The ionomer resin and polycarbodiimide-containing resin are chosen to optimize adhesion parameters, creating strong interfacial bonding that maintains layer stability even when the outer cover is thin.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The bonding layer uses a composite resin system combining polycarbodiimide with polycarbonate and/or polyether-type aqueous polyurethane dispersion. This composite approach leverages the compatibility between polycarbodiimide and polyurethane while the ionomer resin intermediate layer provides the necessary affinity with the base resin, achieving both compatibility and strong adhesion.

Inventive Principle:
Principle #40Composite materials

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 maintains durability and spin performance on approach shots by improving adhesion between layers, even with a thinly designed soft urethane cover, ensuring the golf ball's performance and longevity.

Implementation Method 1

providing, between the intermediate layer and the outer layer, a bonding layer made of a specific polycarbodiimide-containing polycarbonate and/or polyether-type aqueous polyurethane dispersion composition

Methodology Applied
Scientific EffectChemical bonding: Chemical Bonding

Implementation Method 2

forming the intermediate layer of a resin composition which contains a specific acid-containing polymer or ionomer resin, forming the outer layer of, as the chief component, a polyurethane or polyurea

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentUS9950214B2Multi-piece solid golf ball
Publication Date: 2018.04.24 BRIDGESTONE SPORTS CO LTD

AI summary

A multi-piece solid golf ball having a core, at least one intermediate layer encasing the core and at least one outer layer encasing the intermediate layer is characterized in that the intermediate layer is formed of a resin composition containing a specific acid-containing polymer or ionomer resin, and the outer layer is formed of primarily a polyurethane or a polyurea. The ball also has, between the intermediate layer and the outer layer, a bonding layer made of a polycarbonate and/or polyether-type aqueous polyurethane dispersion composition which includes a specific aqueous polycarbodiimide.