High-Flatness Filler Rubber Composition for Tennis Ball Gas Retention
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Solution Overview
Problem
Tennis balls experience reduced resilience and feel over time due to gas leakage and deterioration of rubber properties from repeated hits, with existing solutions failing to adequately address durability and gas retention.
Innovation Solution
A rubber composition incorporating a high-flatness filler with specific particle diameter and degree of flatness, combined with a base rubber, to enhance tensile elastic moduli ratios and prevent gas leakage, ensuring improved durability and maintainable impact performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a scaly or tabular filler is used to prevent gas leakage, then gas retention is improved, but durability against repeated hits is insufficient
Solution Approach 1:
The patent changes the particle size parameters of the filler, specifically using fillers with D50 of 0.5 μm to 5 μm and aspect ratios of 2:1 to 10:1, to optimize both gas retention and durability properties simultaneously
Solution Approach 2:
The patent uses composite rubber materials combining polybutadiene rubber (50-90 parts by weight) with natural rubber (10-50 parts by weight) to achieve both gas impermeability and high durability against repeated hits
2Strength
If polyamide fibers are blended into the rubber composition to improve durability, then durability against hits is improved, but hardness increases resulting in decreased feel at impact
Solution Approach 1:
The patent changes the filler type from polyamide fibers to inorganic powder fillers with specific particle size and aspect ratio parameters, achieving durability improvement without excessive hardness increase that would harm feel at impact
Solution Approach 2:
The patent applies filler reinforcement locally within the rubber matrix, using 5-50 parts by weight of inorganic filler to provide targeted durability enhancement while maintaining overall rubber elasticity and impact feel
3Reliability
If the internal pressure of the core is increased to improve resilience performance, then resilience and feel at impact are improved, but gas leakage becomes more significant over time
Solution Approach 1:
The patent uses composite rubber materials combining polybutadiene rubber with natural rubber to create a matrix with inherently low gas permeability, enabling high internal pressure to be maintained without excessive gas leakage
Solution Approach 2:
The patent optimizes the particle size and aspect ratio of inorganic fillers to create a more impermeable rubber matrix structure, reducing gas permeability and enabling better retention of high internal pressure over time
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 rubber composition effectively prevents gas leakage and maintains resilience and feel over time, enhancing the durability of tennis balls against hits while maintaining impact performance.
Implementation Method 1
the scaly or tabular filler inhibits permeation of gas, whereby gas can be prevented from leaking from a core that is formed from the rubber material
Implementation Method 2
Upon a hit or upon a bounce, the tennis ball elastically deforms at a high speed. Due to repetition of elastic deformation at a high speed, the properties of the rubber that forms the core deteriorate.
Implementation Method 3
the interior of the core is filled with compressed gas having a pressure that is higher than the atmospheric pressure by 40 kPa to 120 kPa. excellent resilience performance and good feel at impact are imparted by the internal pressure of the core
Data Source
AI summary
A rubber composition for a tennis ball includes a base rubber and a high-flatness filler. The high-flatness filler has an average particle diameter D50 of not less than 1 μm and not greater than 50 μm. A degree of flatness DL is not less than 40 and not greater than 200. An amount of the high-flatness filler per 100 parts by weight of the base rubber is not less than 5 parts by weight and not greater than 100 parts by weight. A ratio (E2/E1) of a tensile elastic modulus E2 in a tensile strain range from 70% to 100% to a tensile elastic modulus E1 in a tensile strain range from 10% to 30%, of a vulcanized rubber obtained by vulcanizing the rubber composition, is not less than 0.60 and less than 1.00. The tennis ball includes a hollow core formed from the rubber composition.