Thermoset Polyurethane Golf Ball Cover Microhardness Gradient
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Solution Overview
Problem
Existing golf balls with thermoset polyurethane cover layers require fatty acid and/or fatty acid salts to achieve hardness gradients, which can make the cover surface unduly brittle and increase manufacturing costs.
Innovation Solution
A golf ball design featuring a core with a positive hardness gradient and an outer cover layer formed from thermoset polyurethane, where the cover layer has a treated region with a thermoset polyurethane microhardness-increasing solution containing an isocyanate portion and a non-aqueous solvent, creating a microhardness gradient without the need for fatty acids or salts, maintaining mechanical strength and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If fatty acid and/or fatty acid salts are used to create hardness gradient in thermoset polyurethane cover layer, then hardness gradient is achieved, but cover surface becomes unduly brittle and manufacturing costs increase
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition parameters of the thermoset polyurethane system. Specifically, it adjusts the isocyanate index (NCO/OH ratio) and incorporates hydroxyl-functionalized ingredients to create a microhardness gradient without relying on fatty acid additives. This changes the crosslinking density and chemical structure parameters to achieve the desired hardness variation while maintaining mechanical integrity.
Solution Approach 2:
The patent implements local quality by creating a spatial variation in microhardness within the cover layer. The microhardness gradient is established through controlled diffusion of isocyanate components from the interior toward the exterior surface, resulting in different crosslinking densities at different locations. This produces a hardness profile that varies locally from the core-interface region to the outer surface, optimizing both durability and feel characteristics.
2Manufacturing precision
If fatty acid and/or fatty acid salts are used to achieve hardness gradient, then hardness gradient is achieved, but manufacturing costs increase
Solution Approach 1:
The patent eliminates the need for fatty acid additives by changing the formulation parameters of the thermoset polyurethane system. It uses hydroxyl-functionalized ingredients and controls the isocyanate index to achieve hardness gradient through the inherent chemistry of the polyurethane system rather than through additive-based modification, thereby reducing material costs and simplifying the manufacturing process.
Solution Approach 2:
The patent extracts and eliminates the dependency on fatty acid and fatty acid salt additives from the formulation. By removing these optional additives and relying instead on the controlled chemistry of hydroxyl-functionalized polyurethane components, the invention simplifies the material system and reduces manufacturing complexity and cost.
3Strength
If thermoset polyurethane material is used for outer cover layer, then mechanical strength and durability are improved, but adhesion issues between layers occur
Solution Approach 1:
The patent addresses adhesion issues by modifying the chemical parameters of the thermoset polyurethane system. It incorporates hydroxyl-functionalized ingredients that provide reactive hydroxyl groups capable of forming strong chemical bonds with the underlying core layer. The isocyanate index and functional group ratios are optimized to ensure adequate crosslinking while maintaining adhesion to the core.
Solution Approach 2:
The patent creates a composite material system where the thermoset polyurethane cover layer is chemically integrated with the core layer. The hydroxyl-functionalized polyurethane components form a chemically bonded interface with the core, creating a reliable composite structure that combines the high strength of thermoset polyurethane with strong adhesion to the underlying layer.
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 allows for cost-effective production of golf balls with enhanced mechanical strength, impact durability, and cut resistance, while avoiding brittleness and adhesion issues between layers, by creating a microhardness gradient within a single thermoset polyurethane layer.
Implementation Method 1
The treated region comprises the isocyanate portion and has a microhardness M1 that is greater than a microhardness M2 of the untreated region
Implementation Method 2
a thermoset polyurethane microhardness-increasing solution consisting of an isocyanate portion and at least one non-aqueous solvent
Data Source
AI summary
Golf ball comprising a positive hardness gradient core and an outer cover layer having a microhardness gradient and being formed from a thermoset polyurethane material throughout, and having: i) a treated region that is contacted with a thermoset polyurethane microhardness-increasing solution consisting of an isocyanate portion and at least one non-aqueous solvent; and ii) an untreated region that is not contacted with the thermoset polyurethane microhardness-increasing solution. The treated region comprises the isocyanate portion, whereas the untreated region does not comprise the isocyanate portion. Treated region has a microhardness M1 that is greater than microhardness M2 of untreated region to define the outer cover layer positive microhardness gradient ΔM=M1−M2. The treated region may have a depth Dtr that extends inward from the cover outer surface and in some embodiments is less than a thickness of the untreated region. Treated region may alternatively extend from the inner surface toward outer surface.