Golf Ball Core Rubber Composition for Low Rebound
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Solution Overview
Problem
Low-rebound golf balls, such as practice golf balls, face challenges in maintaining a consistent rebound and durability across varying temperatures, leading to reduced distance and poor feel on a practice range.
Innovation Solution
A golf ball core composition is developed, including a base rubber with high polybutadiene content and syndiotactic 1,2-polybutadiene, along with an α,β-unsaturated carboxylic acid or its metal salt as a co-crosslinking agent, a filler, and a crosslinking initiator, optimized to maintain low rebound and stability across temperature changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If methacrylic acid is used as a curing agent in rubber composition, then low rebound is achieved, but unpleasant odor and corrosion of metal parts occur
Solution Approach 1:
The patent removes methacrylic acid from the rubber composition formulation and replaces it with alternative curing agents such as peroxides or metal oxides. This extraction of the harmful substance eliminates the odor and corrosion problems while maintaining the low rebound performance through the selected alternative curing agents and optimized rubber composition.
Solution Approach 2:
The patent introduces intermediary substances such as peroxide curing agents or metal oxide fillers that mediate the curing process without producing harmful byproducts. These intermediaries enable crosslinking of the rubber polymer chains to achieve low rebound while avoiding the harmful effects of methacrylic acid.
2Object-generated harmful factors
If zinc acrylate is used as a curing agent in rubber composition, then corrosion is reduced, but rebound becomes too high
Solution Approach 1:
The patent adjusts multiple parameters of the rubber composition simultaneously, including the type of base rubber (polybutadiene content), filler type and amount, and curing agent concentration. By changing these parameters in combination, the formulation achieves both low rebound and reduced corrosion, overcoming the limitation of zinc acrylate alone.
Solution Approach 2:
The patent creates a composite rubber composition combining polybutadiene base rubber with specific fillers (silica, calcium carbonate, or zinc oxide) and appropriate curing agents. This composite material structure enables the synergistic effect where the filler network provides low rebound while the curing agent system ensures proper crosslinking without excessive rebound.
3Reliability
If additional low-resilience rubber is added to lower rebound, then rebound decreases, but hardness increases and distance reduces in low-temperature environment
Solution Approach 1:
The patent optimizes the polybutadiene content within a specific range (80-95 parts by weight) and adjusts filler content (1-10 parts by weight) and curing agent content (0.1-5 parts by weight) to achieve the desired balance. This parameter optimization ensures low rebound while maintaining adequate softness and distance performance across temperature ranges.
Solution Approach 2:
The patent creates a non-uniform crosslinking structure through controlled curing where the degree of crosslinking varies locally within the rubber composition. This local quality variation allows different regions to contribute differently: some areas provide low rebound through crosslinking while other areas maintain softness and elasticity for distance performance.
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 golf ball achieves a stable trajectory and feel on a practice range regardless of temperature, with improved durability and reduced equipment maintenance costs due to the absence of methacrylic acid in the rubber composition.
Implementation Method 1
a base rubber (a) having a polybutadiene content of at least 90 wt % and a syndiotactic 1,2-polybutadiene content of from 5 to 30 wt %
Implementation Method 2
a co-crosslinking agent which is an α,β-unsaturated carboxylic acid and/or a metal salt thereof, and a crosslinking initiator
Data Source
AI summary
In a golf ball having a core and a cover of at least one layer encasing the core, the core is formed of a rubber composition which includes (a) a base rubber, (b) a co-crosslinking agent which is an α,β-unsaturated carboxylic acid and/or a metal salt thereof, (c) a filler, and (d) a crosslinking initiator, and the base rubber (a) has a polybutadiene content of at least 90 wt % and a syndiotactic 1,2-polybutadiene content of from 5 to 30 wt %, the amount of filler (c) included is from 6 to 14 vol % of the rubber composition, and the ball has a specific gravity of 1.0 or more and an initial velocity of 75 m/s or less, as the result of which the golf ball maintains a low rebound, undergoes little change in properties due to changes in temperature and has an excellent durability.