Tyre Tread Zinc Reduction for Vulcanization Kinetics
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Solution Overview
Problem
Current tire tread compositions for heavy-load, high-speed vehicles face challenges with long vulcanization delay phases and slower reaction speeds when using natural rubber and inorganic fillers like silica, which can harm other tire components and require high cooking times, while also having environmental concerns due to high zinc levels.
Innovation Solution
Reducing the zinc content in rubber formulations based on natural rubber and reinforced with silica, from 0.7 to 2 phr, without replacing it with another metal, to overcome the delay phase issue while maintaining the benefits of silica reinforcement, and incorporating a sulfur crosslinking system, a coupling agent, and a plasticizer with a content less than or equal to 10 phr.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If inorganic fillers such as silica are used to reduce rolling resistance and improve wear resistance, then the reinforcing effect and reduced hysteresis are achieved, but the vulcanization reaction rate decreases and the delay phase increases
Solution Approach 1:
The patent changes the chemical composition parameters of the vulcanization system by reducing zinc content to 0.7-2 phr and adjusting accelerator ratios. This parameter optimization resolves the contradiction by enabling faster vulcanization kinetics while preserving the low hysteresis benefits of silica reinforcement, as demonstrated by reduced cure times in the patent data.
2Productivity
If zinc content is increased to improve vulcanization kinetics, then the vulcanization reaction rate increases, but the environmental impact increases
Solution Approach 1:
The patent optimizes the zinc content parameter to a specific range (0.7-2 phr) and adjusts the accelerator package composition to achieve effective vulcanization kinetics with minimized zinc usage. This resolves the contradiction by demonstrating that lower zinc levels combined with optimized accelerators can maintain productivity while reducing environmental harm from zinc compounds.
3Loss of time
If high zinc content is used to accelerate vulcanization, then the curing time is reduced, but the harmful effects on water and aquatic organisms increase
Solution Approach 1:
The patent implements precise parameter control by limiting zinc content to 0.7-2 phr and optimizing the accelerator-to-zinc ratio. This resolves the contradiction by achieving adequate curing speed through accelerated chemistry rather than excessive zinc, thereby reducing the environmental footprint while maintaining acceptable production timelines.
4Loss of energy
If predominantly inorganic fillers are used in combination with natural rubber, then the rolling resistance is reduced, but the vulcanization kinetics are retarded
Solution Approach 1:
The patent optimizes the chemical parameters of the vulcanization system including zinc content (0.7-2 phr), accelerator types and ratios, and curing temperature profiles. These parameter adjustments compensate for the retarding effect of inorganic fillers on vulcanization kinetics, enabling the composition to achieve both low rolling resistance and acceptable cure times.
Solution Approach 2:
The patent employs organic accelerators as intermediary substances that facilitate the vulcanization reaction between natural rubber and silica-filled compounds. These accelerators mediate the interaction between the polymer and filler, enabling effective crosslinking despite the presence of inorganic fillers that would otherwise retard the reaction.
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
This approach allows for improved vulcanization kinetics, reduced rolling resistance, and enhanced wear resistance of tire treads, while minimizing environmental impact by reducing zinc levels and maintaining the benefits of silica reinforcement.
Implementation Method 1
the use of certain specific inorganic fillers described as 'reinforcing ', such as silica, exhibiting high dispersibility
Implementation Method 2
the vulcanization of diene elastomers with sulfur is widely used in the rubber industry
Implementation Method 3
a relatively complex vulcanization system is used, comprising, in addition to sulfur, various vulcanization accelerators as well as one or more vulcanization activators, particularly zinc derivatives such as zinc oxide (ZnO)
Data Source
AI summary
The invention relates to a tyre tread having a rubber composition based on at least one natural or synthetic polyisoprene, in a proportion of between 50 pce and 100 pce, a reinforcing filler comprising predominantly in terms of weight of the inorganic filler, a coupling agent, a plasticiser in a proportion lower than or equal to 10 pce and a sulphur cross-linking system, characterised in that the composition contains between 0.7 and 2 pce of zinc.