Tire Carcass Rubber Compound With Anti-Reversion Vulcanization
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Solution Overview
Problem
Existing rubber compounds for tire carcasses face challenges in balancing handling, rolling resistance, viscosity, and reversion properties, as improving one property often worsens others, particularly due to increased carbon black content which affects processing and vulcanization.
Innovation Solution
A rubber compound with a polymer base comprising at least 50% natural rubber, carbon black as filler, and a vulcanization system consisting of a mixture of sulfenamides and anti-reversion agents, such as N-t-butylbenzothiazole-2-sulfenamide and hexamethylene bis(thiosulfate, to optimize vulcanization without increasing carbon black content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the content of carbon black in the compound is increased to improve handling stiffness, then handling performance is improved, but rolling resistance increases and processing conditions worsen
Solution Approach 1:
The patent changes the chemical composition parameters of the vulcanization system by introducing a specific mixture of sulfenamide accelerators and anti-reversion agents in defined ratios (25-80% accelerator, 75-20% anti-reversion agent). This chemical parameter change enables achieving the desired handling stiffness through optimized cross-linking rather than through increased carbon black content, thereby avoiding the penalty of increased rolling resistance
Solution Approach 2:
The patent creates a composite vulcanization system combining multiple components (sulfur, sulfenamide accelerators, anti-reversion agents) in specific proportions. This composite approach produces a synergistic effect where the combination of ingredients achieves superior handling properties and controlled reversion without requiring additional carbon black, thus maintaining lower rolling resistance
2Strength
If the content of carbon black in the compound is increased to improve handling stiffness, then handling performance is improved, but viscosity increases and processing conditions worsen
Solution Approach 1:
The patent modifies the vulcanization system composition parameters to include anti-reversion agents that control degradation during processing. This enables maintaining lower carbon black content while still achieving adequate handling stiffness, thereby keeping viscosity and processing conditions within acceptable ranges
3Strength
If the content of carbon black in the compound is increased, then handling stiffness is improved, but reversion phenomenon during vulcanization worsens
Solution Approach 1:
The patent introduces anti-reversion agents as intermediary substances that mediate between the cross-linking process and the rubber polymer. These agents (comprising 75-20% of the vulcanization system mixture) prevent the degradation and reversion phenomena that would otherwise occur during vulcanization, enabling reliable processing even with optimized carbon black content for handling stiffness
4Ease of operation
If natural rubber content is increased to achieve optimal balance of properties, then handling and rolling resistance balance is improved, but reversion susceptibility increases
Solution Approach 1:
The patent uses anti-reversion agents as intermediary substances that specifically protect natural rubber from reversion during vulcanization. These agents intervene in the chemical reactions to prevent polymer degradation, enabling the use of high natural rubber content (at least 50% of polymer base) to achieve optimal handling and rolling resistance balance without suffering from reversion problems
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 solution achieves a balanced improvement in handling, rolling resistance, viscosity, and reversion properties without worsening any of these factors, demonstrating effectiveness across various carbon black concentrations and ensuring optimal performance with the specified natural rubber quantity.
Implementation Method 1
a vulcanization system comprising sulphur; said compound being characterized in that said vulcanization system comprises a mixture of at least one accelerator and at least one anti-reversion agent
Implementation Method 2
a polymer base with a cross-linkable unsaturated chain comprising at least 50% by weight of the polymer base of natural rubber
Implementation Method 3
at least one accelerator belonging to the class of sulfenamides
Implementation Method 4
the reversion phenomenon, besides implying a given degree of rubber degradation, necessarily requires an accurate control of the vulcanization process
Data Source
AI summary
A rubber compound for tire carcass portions comprising at least a polymer base with a cross-linkable unsaturated chain comprising at least 50% by weight of the polymer base of natural rubber, a filler comprising carbon black and a vulcanization system comprising sulphur. The vulcanization system comprises a mixture of at least one accelerator and at least one anti-reversion agent, said mixture consisting of 25 to 80% by weight of the mixture of at least one accelerator belonging to the class of sulfenamides and 75 to 20% by weight of the mixture of at least one anti-reversion agent.