Tri-component Carbon Black Rubber Compound for Air Impermeability
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Solution Overview
Problem
The pneumatic tyre industry faces challenges in achieving high impermeability in the innerliner and body ply skim layers to reduce air diffusion and oxidative degradation, while also seeking to minimize tyre weight and rolling resistance.
Innovation Solution
A rubber compound comprising a cross-linkable unsaturated chain polymer base, a filler system with a mixture of three types of carbon black having significantly different surface areas (25-40 m^2/g, 70-90 m^2/g, and 800-1200 m^2/g) is used, which when vulcanized, enhances air impermeability without increasing filler content, allowing for a potential reduction or elimination of the innerliner layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the impermeability of the innerliner layer is increased by traditional means (increasing thickness or filler content), then air diffusion is reduced, but the weight of the pneumatic tyre increases
Solution Approach 1:
The invention uses a composite filler system combining three types of carbon black with different surface areas (25-40 m²/g, 70-90 m²/g, and 800-1200 m²/g) to achieve high impermeability. This composite approach creates a synergistic effect where the combination of fillers provides superior air barrier properties compared to individual fillers, allowing reduced innerliner thickness and weight while maintaining high impermeability standards.
2Weight of moving object
If the thickness of the innerliner layer is reduced to decrease weight, then the weight of the pneumatic tyre decreases, but the impermeability to air is compromised
Solution Approach 1:
The invention changes the parameters of the filler system by introducing a specific tri-component carbon black mixture with defined surface area ranges and weight ratios. This parameter optimization allows the innerliner to achieve enhanced impermeability per unit thickness, enabling weight reduction through thinner layers while compensating for the reduced thickness through superior material properties.
3Reliability
If the filler content is increased to improve impermeability, then air diffusion is reduced, but the mechanical characteristics of the rubber compound deteriorate
Solution Approach 1:
The invention applies local quality by assigning different functional roles to each carbon black type based on its surface area characteristics. The first carbon black (25-40 m²/g) provides structural foundation, the second (70-90 m²/g) enhances impermeability, and the third (800-1200 m²/g) creates tortuous pathways for air molecules. This functional differentiation allows each filler to contribute optimally to specific properties, achieving high impermeability without compromising overall mechanical strength.
4Ease of manufacture
If a single type of carbon black is used in the filler system, then the compound formulation is simple, but the impermeability to air is insufficient
Solution Approach 1:
The invention employs a composite filler system with three distinct carbon black types, each selected for specific surface area properties that contribute to different aspects of impermeability. The synergistic interaction between these fillers creates a network structure that significantly enhances air barrier properties beyond what any single carbon black could achieve alone, justifying the slightly more complex formulation through superior 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 solution significantly improves air impermeability with a synergistic effect among the fillers, maintaining mechanical characteristics and enabling a reduction in tyre weight and oxidative degradation, thus extending tyre service life and reducing energy consumption.
Implementation Method 1
the use of a mixture of fillers having a wide distribution of surface areas... is able to ensure significant improvements in terms of the impermeability to air of the resulting rubber portion
Implementation Method 2
The inventors have demonstrated that amongst fillers with significantly different surface areas a synergistic effect, in terms of impermeability to air, is made
Data Source
AI summary
An innerliner and/or body ply skim rubber compound comprising at least: - a cross-linkable unsaturated chain polymer base, - a filler system, and - a vulcanization system; The filler system comprises, for at least 50% by weight, a mixture of at least three different types of carbon black comprising a first carbon black with a surface area of between 25 and 40 m2/g, a second carbon black with a surface area of between 70 and 90 m2/g and a third carbon black with a surface area of between 800 and 1200 m2/g.