Dual-Cured Polyurethane-Polyurea Golf Ball Covers
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Solution Overview
Problem
Golf ball materials face challenges in achieving a balance between hardness, durability, and control, with conventional polyurethane and polyurea compositions being too soft and prone to durability issues, while ionomer resins provide durability but at the cost of lower spin rates and control due to their hardness.
Innovation Solution
The development of crosslinked polyurethane and polyurea compositions that include both hard and soft segment crosslinking, using a conjugated diene with terminal amino or hydroxy groups reacted with an isocyanate-containing component and a curative blend to form a prepolymer with urea and urethane linkages, resulting in a material with a hardness of 60 Shore D or greater.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional polyurethane and polyurea compositions are used for golf ball covers, then the material provides a soft feel and greater control through increased spin, but the material exhibits relative softness that introduces durability issues
Solution Approach 1:
The patent employs composite materials by combining polyurethane and polyurea components in a single castable composition. This creates a hybrid material system where the polyurethane segments provide softness and control characteristics, while the polyurea segments contribute durability and hardness. The composite nature of the material allows simultaneous achievement of both control (through soft polyurethane phases) and durability (through hard polyurea phases) that cannot be obtained with either material alone.
Solution Approach 2:
The patent utilizes parameter changes by controlling the isocyanate index (NCO content) and the ratio of polyurethane to polyurea components in the composition. By adjusting these parameters, the final cured material achieves optimal balance between hardness/durability and softness/control. The dual-curing process also introduces parameter changes through sequential chemical reactions that transform the material properties during manufacturing.
2Reliability
If ionomer resins are used for golf ball cover materials, then the material provides durability, rebound, and scuff resistance characteristics, but the hardness of the material results in a hard feel and generally lower spin rate and control
Solution Approach 1:
The patent creates a composite material system that replaces ionomer resins with a polyurethane-polyurea hybrid. This composite approach allows the material to achieve durability through crosslinked polyurea segments while maintaining softness and control through polyurethane segments. The composite structure eliminates the need for ionomers' hard thermoplastic matrix, instead using a flexible elastomeric system with embedded hard phases for durability.
3Ease of operation
If blends of hard ionomer resins with softer polymeric materials are used to compensate for hard feel and durability issues, then the material attempts to balance hardness and softness, but the incompatibility of components results in processing difficulties and inferior golf ball properties such as poor durability and cut resistance
Solution Approach 1:
The patent resolves processing incompatibility issues by changing the fundamental parameter of material chemistry from physical blends to chemical reactions. The isocyanate-reactive components chemically react to form a unified crosslinked network, eliminating the phase separation and incompatibility problems inherent in physical blends of ionomers and polyures. This chemical parameter change ensures homogeneous mixing and cure without processing difficulties.
Solution Approach 2:
The patent uses composite materials chemistry where isocyanate groups react with both hydroxyl and amine groups to form an integrated polyurethane-polyurea network. This chemically bonded composite structure eliminates the component incompatibility that plagues physical blends, creating a homogeneous material system with uniform properties throughout that cures reliably without processing issues.
4Ease of operation
If conventional polyurethane cover materials are formed of aromatic components, then the material produces soft covers with greater control, but ultraviolet degradation of the material leads to yellowing
Solution Approach 1:
The patent addresses UV degradation by changing the chemical composition parameters from aromatic to aliphatic hydrocarbon backbones. This parameter change in the molecular structure eliminates the chromophores responsible for UV absorption and yellowing, while maintaining the elastomeric properties needed for soft covers and control. The aliphatic polyurea-polyurethane composition provides both UV stability and desired mechanical properties.
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, durability, and control by achieving higher hardness and flexural modulus values, while maintaining hydrophobicity, thus addressing the limitations of existing materials.
Implementation Method 1
reacting the prepolymer and curative blend to form a composition including urea linkages, urethane linkages, or a combination thereof
Implementation Method 2
crosslinks between the hydrocarbons
Implementation Method 3
forming a curative blend including an amine-terminated curing agent, a hydroxy-terminated curing agent, or a combination thereof and an organic peroxide
Implementation Method 4
maintaining hydrophobicity
Data Source
AI summary
Compositions for golf balls that include polyurethane and/or polyurea linkages and that are crosslinked in the soft segments of the polymer backbone. In particular, the compositions of the invention, which are based on a polyurethane and/or polyurea, have improved crosslink density and hardness from the crosslinking between the soft, unsaturated segments of the polymer backbone. The curative blend includes at least one isocyanate-reactive component and a free radical initiator.