Crosslinked Polyurethane Golf Ball Cover Injection Molding
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Solution Overview
Problem
Existing golf ball cover technologies using thermoplastic polyurethane suffer from inadequate scuff resistance, light resistance, and yellowing issues due to the use of aromatic isocyanates, which affect the physical properties and longevity of the golf ball when exposed to light.
Innovation Solution
A golf ball design incorporating a crosslinked polyurethane outer cover formed by reacting thermoplastic polyurethane with a specific isocyanate crosslinking agent, which includes a compound represented by Chemical Formula 1, to enhance scuff and light resistance, and is produced through injection molding to avoid the limitations of casting methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If thermoplastic polyurethane is used for the golf ball cover, then injection molding is possible with high productivity, but scuff resistance and light resistance are insufficient
Solution Approach 1:
The patent uses a dual-component system combining thermoplastic polyurethane (TPU) with a crosslinking agent. The TPU provides injection moldability and basic mechanical properties, while the crosslinking agent (containing isocyanate groups) creates additional crosslinked structures within the TPU matrix. This composite approach maintains the processing advantages of thermoplastics while introducing the enhanced scuff resistance and light resistance characteristic of crosslinked networks, directly resolving the contradiction between productivity and reliability.
Solution Approach 2:
The patent modifies the chemical structure of TPU by introducing crosslinking through reaction with isocyanate-containing compounds. This changes the molecular architecture from linear/branched (thermoplastic) to partially crosslinked, altering key parameters such as gel fraction, crosslink density, and network topology. These parameter changes enable the material to maintain injection moldability while achieving superior scuff resistance and light resistance that pure TPU cannot provide.
2Reliability
If aromatic isocyanate is used to crosslink thermoplastic polyurethane, then scuff resistance is improved, but light resistance deteriorates due to yellowing
Solution Approach 1:
The patent applies local quality by using a heterogeneous crosslinking system where aromatic and aliphatic isocyanates are combined in specific ratios. The aromatic isocyanate components (providing scuff resistance through rigid structures) are distributed within a matrix containing aliphatic isocyanates (providing UV stability). This local distribution of different isocyanate types with complementary properties allows the cover to achieve both high scuff resistance and excellent light resistance simultaneously.
Solution Approach 2:
The crosslinking agent itself is a composite material combining aromatic isocyanate (for scuff resistance) and aliphatic isocyanate (for light resistance). This composite crosslinking agent creates a dual-function crosslinked network within the TPU, where aromatic segments provide mechanical durability and aliphatic segments provide UV stability, eliminating the yellowing problem while maintaining scuff resistance.
3Object-affected harmful factors
If casting molding method is used for thermosetting polyurethane, then light resistance is improved, but productivity decreases due to long curing time
Solution Approach 1:
The patent replaces the chemical curing mechanism of thermosetting polyurethane with a physical injection molding process. Instead of relying on slow chemical reactions between prepolymer and curing agent (casting method), the invention uses the thermoplasticity of TPU to enable rapid injection molding. The crosslinking then occurs in-situ during or after molding through reaction with the crosslinking agent, achieving both high productivity (from injection molding) and excellent light resistance (from the crosslinked structure).
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 crosslinked polyurethane cover provides improved scuff resistance, light resistance, and maintains color stability with minimal color change after exposure to light, while also enhancing mechanical properties such as tensile strength and tear resistance, and can be produced with reduced facility investment costs.
Implementation Method 1
a crosslinking agent comprising an isocyanate crosslinking agent and a compound represented by Chemical Formula 1
Implementation Method 2
the outer cover having a crosslinked structure formed by adding a crosslinking agent to thermoplastic polyurethane (TPU) and then performing extrusion reaction
Data Source
AI summary
A golf ball according to an embodiment of the present disclosure is covered with an injection-molded crosslinked polyurethane. The golf ball may have excellent scuff resistance and light resistance of a cover as well as excellent driving distance and spin by using a cover composition containing crosslinked polyurethane obtained by adding a crosslinking agent to thermoplastic polyurethane (TPU). A polyurethane cover composition according to an embodiment can make it possible to prepare a crosslinked polyurethane cover by injection molding without the burden of facility investment cost.