Thermoplastic Polyurethane Golf Ball Cover Cross-Linking
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Solution Overview
Problem
Conventional isocyanate treatment methods for thermoplastic polyurethane golf ball covers are costly and inefficient, requiring additional steps that compromise process efficiency and do not consistently produce golf balls with desirable physical and playing performance properties.
Innovation Solution
A method involving the application of a first polyurethane coating with unreacted isocyanate groups, followed by heat treatment, and a second polyurethane coating with a lower isocyanate index, applied using spray-coating techniques, enhances the durability and performance of the golf ball covers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional isocyanate treatment methods are used for thermoplastic polyurethane golf ball covers, then cross-linking is achieved, but the process becomes costly and inefficient with additional steps that compromise process efficiency
Solution Approach 1:
The patent combines the cross-linking treatment and coating application into a single integrated process step. The polyurethane coating contains embedded isocyanate groups that cross-link with the thermoplastic polyurethane cover during a single curing cycle, eliminating the need for separate isocyanate treatment steps and improving process efficiency while achieving the desired mechanical strength enhancement
Solution Approach 2:
The isocyanate groups are pre-incorporated into the polyurethane coating formulation before application. This preliminary incorporation of cross-linking agents into the coating allows the cross-linking reaction to occur simultaneously with coating curing, eliminating subsequent separate treatment steps and streamlining the manufacturing process
2Reliability
If conventional isocyanate treatment methods are used, then some cross-linking is achieved, but the method does not consistently produce golf balls with desirable physical and playing performance properties
Solution Approach 1:
The patent modifies the chemical parameters of the coating system by incorporating polyisocyanate groups into the polyurethane coating formulation. This parameter change enables consistent cross-linking density and improves the reliability of physical and playing performance properties. The dual-coat system with specific isocyanate indices provides controlled cross-linking that consistently achieves desirable performance characteristics
Solution Approach 2:
The patent uses a composite coating system consisting of a first polyurethane coat with high isocyanate index (≥115) for cross-linking and a second polyurethane coat with lower isocyanate index (<96) for surface properties. This composite material approach ensures consistent cross-linking throughout the coating while maintaining desirable surface characteristics, leading to reliable and repeatable golf ball performance
3Duration of action of stationary object
If a single polyurethane coating is applied, then the process is simple, but the cover lacks sufficient durability and scuff-resistance
Solution Approach 1:
The patent divides the coating into two distinct layers: a first polyurethane coat containing polyisocyanate groups for cross-linking and durability, and a second polyurethane coat with lower isocyanate index for surface quality and scuff-resistance. This segmentation of functions into separate layers achieves enhanced durability and scuff-resistance while maintaining a manageable two-step coating process
4Strength
If the first polyurethane coating has high isocyanate index (≥115), then cross-linking is enhanced for better strength, but the coating may be too reactive
Solution Approach 1:
The first polyurethane coating with high isocyanate index acts as an intermediary layer that provides cross-linking functionality without direct contact with the final playing surface. The second polyurethane coat with lower isocyanate index serves as a protective intermediary between the highly reactive first coat and the external environment, moderating the reactivity while allowing the underlying cross-linked structure to provide mechanical strength
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
This method improves the mechanical strength, impact durability, and scuff-resistance of golf ball covers, resulting in enhanced playing performance and cost-effectiveness by optimizing the cross-linking process.
Implementation Method 1
applying a first polyurethane coating comprising unreacted isocyanate groups and having an isocyanate index of at least about 115 to the outer cover layer; treating the golf ball with heat
Implementation Method 2
treating the golf ball with heat
Implementation Method 3
applying a first polyurethane coating... by spray-coating techniques
Data Source
AI summary
A coated golf ball includes a single or dual core and a cover layer formed from a thermoplastic polyurethane (TPU). The TPU cover preferably has a first polyurethane coating layer and a second polyurethane coating layer disposed about the first polyurethane coating layer. In a preferred embodiment, he first polyurethane coating layer includes unreacted isocyanate groups and has an isocyanate index of at least about 120. Preferably, the first polyurethane coating layer has an isocyanate index of at least about 150, more preferably, at least about 200, and most preferably at least about 250.