Aqueous Tennis Ball Adhesive Curing Dynamics
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Solution Overview
Problem
Existing aqueous adhesives for tennis ball cores lack sufficient adhesive strength and durability, with high curing rates reducing fluidity and leading to incomplete adhesion, while low curing rates fail to provide adequate adhesive strength.
Innovation Solution
An aqueous adhesive comprising natural or synthetic rubber latex, a sulfenamide-based vulcanization accelerator, and an inorganic filler, with specific torque time and ratio parameters to ensure appropriate curing and adhesion, is developed to enhance the adhesive strength and durability of tennis ball cores.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If an aqueous adhesive with high curing rate is used, then adhesive strength is improved, but fluidity is reduced early causing incomplete adhesion
Solution Approach 1:
The patent applies a two-stage curing process that dynamically adjusts the curing rate. First, heating at 50°C to 100°C for 1-30 minutes provides initial adhesion while maintaining fluidity. Then, heating at 100°C to 200°C for 1-60 minutes completes the curing to achieve maximum adhesive strength. This dynamic temperature staging resolves the contradiction between maintaining fluidity and achieving strong adhesion.
Solution Approach 2:
The patent performs preliminary adhesion at a lower temperature (50°C to 100°C) before final curing. This preliminary action allows the adhesive to maintain fluidity long enough to achieve complete contact between half-cores, ensuring proper wetting and initial bonding. Only after this preliminary adhesion is established does the patent proceed to higher temperature curing to develop full adhesive strength.
2Stability of the object's composition
If an aqueous adhesive with low curing rate is used, then fluidity is maintained, but adhesive strength is insufficient
Solution Approach 1:
The patent uses a two-stage heating process that dynamically controls the curing rate. The first stage (50°C to 100°C for 1-30 minutes) maintains fluidity for complete adhesion. The second stage (100°C to 200°C for 1-60 minutes) accelerates curing to achieve sufficient adhesive strength. This dynamic approach prevents the adhesive from curing too quickly while ensuring final strength requirements are met.
Solution Approach 2:
The patent maintains continuous heating throughout the adhesion and curing process, transitioning smoothly from low-temperature adhesion promotion to high-temperature strength development. This continuous useful action ensures that fluidity is maintained during the critical adhesion phase, then curing is continuously promoted to achieve adequate adhesive strength without interruption.
3Object-affected harmful factors
If aqueous adhesive is used instead of solvent-based adhesive, then environmental impact is reduced, but adhesive strength and durability are insufficient
Solution Approach 1:
The patent changes the curing parameters (temperature and time) to optimize aqueous adhesive performance. By implementing a two-stage heating process (50°C to 100°C for 1-30 minutes, then 100°C to 200°C for 1-60 minutes), the patent achieves adequate adhesive strength and durability from the environmentally friendly aqueous adhesive, matching or exceeding the performance of solvent-based adhesives without the harmful environmental impact.
Solution Approach 2:
The patent uses a composite adhesive system combining aqueous adhesive with a two-stage thermal curing process. This composite approach (aqueous adhesive + controlled heating stages) compensates for the inherently lower strength of aqueous adhesives by optimizing the curing conditions, achieving sufficient adhesive strength while maintaining environmental benefits.
4Speed
If curing progresses before moisture evaporation, then adhesion speed is improved, but adhesive strength is reduced due to moisture retention
Solution Approach 1:
The patent dynamically controls the curing process through two heating stages. The first stage (50°C to 100°C for 1-30 minutes) allows moisture to evaporate while promoting initial adhesion. The second stage (100°C to 200°C for 1-60 minutes) completes curing at higher temperature to ensure moisture removal and achieve maximum adhesive strength. This dynamic staging prevents premature curing that would trap moisture.
Solution Approach 2:
The patent performs preliminary moisture removal at the lower temperature stage (50°C to 100°C) before final curing. This preliminary action ensures that volatile components are driven off during the adhesion phase, preventing moisture retention that would weaken the bond. Only after moisture removal does the patent proceed to high-temperature curing to achieve full strength.
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 adhesive achieves improved close adhesion and high adhesive strength by maintaining fluidity during the adhesion process and ensuring complete removal of volatile components, preventing reduction in adhesive strength due to moisture retention.
Implementation Method 1
a sulfenamide-based vulcanization accelerator... the rubber component in the adhesive is crosslinked
Implementation Method 2
an inorganic filler... ensuring complete removal of volatile components, preventing reduction in adhesive strength due to moisture retention
Data Source
Figure 1
Figure 2A~2B
AI summary
An aqueous adhesive for a tennis ball includes rubber latex and a sulfenamide-based vulcanization accelerator. When a solid content in the aqueous adhesive is measured at a temperature of 150°C by a curelastometer, a 10% torque time t10 is preferably not shorter than 3 minutes and preferably not longer than 15 minutes, and a ratio (tl0/t90) of the 10% torque time t10 to a 90% torque time t90 is preferably not less than 0.60 and preferably not greater than 0.95. A tennis ball includes a hollow core obtained by two semi-spherical half cores being adhered by using the aqueous adhesive.